(BQ) Part 2 book “Principles and practice of mechanical ventilation” has contents: Physiologic effect of mechanical ventilation, artificial airways and management, complications in ventilator-supported patients, management of ventilatorsupported patients,… and other contents.
IX PHYSIOLOGIC EFFECT OF MECHANICAL VENTILATION This page intentionally left blank EFFECTS OF MECHANICAL VENTILATION ON CONTROL OF BREATHING 35 Dimitris Georgopoulos PHYSIOLOGY EFFECTS OF MECHANICAL VENTILATION ON FEEDBACK SYSTEMS Chemical Feedback Response of Respiratory Motor Output to Chemical Stimuli Operation of Chemical Feedback Neuromechanical Feedback Neuromechanical Inhibition Behavioral Feedback The main reasons for instituting mechanical ventilation are to decrease the work of breathing, support gas exchange, and buy time for other interventions to reverse the cause of respiratory failure.1 Mechanical ventilation can be applied in patients who are making or not making respiratory efforts, whereby assisted or controlled modes of support are used, respectively.1 In patients without respiratory efforts, the respiratory system represents a passive structure, and thus the ventilator is the only system that controls breathing During assisted modes of ventilator support, the patient’s system of control of breathing is under the influence of the ventilator pump.2–4 In the latter instance, ventilatory output is the final expression of the interaction between the ventilator and the patient’s system of control of breathing Thus, physicians who deal with ventilated patients should know the effects of mechanical ventilation on control of breathing, as well as their interaction Ignorance of these issues may prevent the ventilator from achieving its goals and also lead to significant patient harm PHYSIOLOGY The respiratory control system consists of a motor arm, which executes the act of breathing, a control center located in the medulla, and a number of mechanisms that convey information to the control center.5,6 Based on information, the control center activates spinal motor neurons that INTERACTIVE EFFECTS OF PATIENT-RELATED FACTORS AND VENTILATOR ON CONTROL OF BREATHING Mechanics of Respiratory System Characteristics of Muscle Pressure Waveform FUTURE CONCLUSION subserve the respiratory muscles (inspiratory and expiratory); the intensity and rate of activity vary substantially between breaths and between individuals The activity of spinal motor neurons is conveyed, via peripheral nerves, to respiratory muscles, which contract and generate pressure (Pmus) According to equation of motion, Pmus at time t during a breath is dissipated in overcoming the resistance (Rrs) and elastance (Ers) of the respiratory system (inertia is assumed to be negligible) as follows: ˙ + Ers × ΔV(t) Pmus(t) = Rrs × V(t) (1) where ΔV(t) is instantaneous volume relative to passive functional residual capacity and V˙ (t) is instantaneous flow Equation (1) determines the volume–time profile and, depending on the frequency of respiratory muscle activation, ventilation Volume–time profile affects Pmus via neuromechanical feedback; inputs generated from other sources (cortical inputs) may modify the function of control center Ventilation, gas-exchange properties of the lung, and cardiac function determine arterial blood gases, termed arterial oxygen tension (PaO 2) and arterial carbon dioxide tension (Pa CO2), which, in turn, affect the activity of control center via peripheral and central chemoreceptors (chemical feedback) This system can be influenced at any level by diseases or therapeutic interventions During mechanical ventilation, the pressure provided by the ventilator (Paw) is incorporated into the system.3 Thus, the total pressure applied to respiratory system at 805 806 Part IX Physiologic Effect of Mechanical Ventilation Ventilator factors Triggering Control Variables Cycling off Patient factors RS mechanics Pmus waveform Response of ventilator to Pmus Pmus(t) + Paw(t) = V (t) · Rrs + ΔV(t ) · Ers Volume–time profile Response of Pmus to ventilator-delivered breath Chemical – Neuromechanical – Behavioral Feedback FIGURE 35-1 Schematic of variables that determine the volume–time profile during mechanical ventilation Neuromechanical, chemical, and behavioral feedback systems are the main determinants of Pmus The functional operation of the ventilator mode (triggering, control, and cycling-off variables) and patient-related factors (namely, respiratory system mechanics and the Pmus waveform) determine the response of the ventilator to Pmus ΔV(t), instantaneous volume relative to passive functional residual capacity of respiratory system; Ers, elastance of the respiratory system; Paw(t), ˙ airway (ventilator) pressure; Pmus(t), instantaneous respiratory muscle pressure; Rrs, resistance of the respiratory system; RS, respiratory system; V (t), instantaneous flow time t [PTOT(t)] is the sum of Pmus(t) and Paw(t) As a result, the equation of motion is modified as follows: PTOT(t) = Pmus(t) + Paw(t) ˙ × Rrs + ΔV(t) × Ers = V(t) (2) The relationships of Equation (2) determine the volume– time profile during mechanical ventilation, which via neuromechanical, chemical, and behavioral feedback systems affects the Pmus waveform (Fig 35-1) The ventilator pressure, by changing flow and volume, may influence these feedback systems and thus alter either the patient’s control of breathing itself or its expression In addition, Pmus, depending on several factors, alters the Paw waveform (Fig 35-1) Thus, during assisted mechanical ventilation (i.e., Pmus ≠ 0), ventilatory output is not under the exclusive influence of patient’s control of breathing; instead, it represents the final expression of an interaction between ventilator-delivered pressure and patient respiratory effort EFFECTS OF MECHANICAL VENTILATION ON FEEDBACK SYSTEMS Chemical Feedback Chemical feedback refers to the response of Pmus to PaO 2, Pa CO2, and pH.5–7 In spontaneously breathing and mechanically ventilated patients, this system is an important determinant of respiratory motor output both during wakefulness and sleep.7–11 Mechanical ventilation can influence chemical feedback simply by altering the three variables PaO 2, Pa CO2, and pH Hypoxemia, hypercapnia, or acidemia may be corrected by mechanical ventilation and thus modify activity of the medullary respiratory controller via peripheral and central chemoreceptors.5,12 The effects of mechanical ventilation on gas-exchange properties of the lung are beyond the scope of this chapter and are discussed in Chapter 37 In this chapter, the fundamental elements of the response of respiratory motor output to chemical stimuli, their relationship to unstable breathing, and the operation of chemical feedback during mechanical ventilation are reviewed Response of Respiratory Motor Output to Chemical Stimuli CARBON DIOXIDE STIMULUS Carbon dioxide (CO2) is a powerful stimulus of breathing.5,12 This stimulus, expressed by Pa CO2, largely depends on the product of tidal volume (VT) and breathing frequency ( f ) (i.e., minute ventilation) according to Equation (3): ˙CO /[V × f(1 − V /V )] Pa CO2 = 0.863 V T D T (3) where VCO2 is CO2 production, and VD/VT is the deadspace-to-tidal-volume ratio Because minute ventilation is an adjustable variable in ventilated patients, understanding the relationship between respiratory motor output and CO2 stimuli is of fundamental importance Chapter 35 807 sleep; propensity increases as CO2 reserve decreases Similar to wakefulness, the response of respiratory motor output to CO2 is mediated mainly by the intensity of respiratory effort, whereas respiratory rate decreases abruptly to zero (apnea) when the CO2 apneic threshold is reached.19 350 300 % of baseline Effects of Mechanical Ventilation on Control of Breathing 250 200 150 100 OTHER CHEMICAL STIMULI 50 20 25 30 40 35 PETCO2 (mm Hg) 45 50 55 FIGURE 35-2 Schematic of the response of respiratory frequency (open squares) and pressure-time product of the inspiratory muscles per breath (an index of the intensity of patient effort, closed squares), both expressed as a percentage of values during spontaneous eupnea (baseline), to CO2 challenge in conscious healthy subjects ventilated with a high level of ventilator assistance PETCO2 is end-tidal PCO2, and the dotted vertical line is PETCO2 during spontaneous breathing (eupnea) Contrast the vigorous response of intensity of inspiratory effort to CO2, even in the hypocapnic range, with the response of respiratory frequency, which remains at eucapnic level over a broad range of CO2 stimuli The response is based on data from references and 13 to 16 Several studies have examined the respiratory motor output to CO2 in ventilated, conscious, healthy subjects.7,13–16 Major findings include Manipulation of Pa CO2 over a wide range has no appreciable effect on respiratory rate Despite hypocapnia, subjects continue to trigger the ventilator with a rate similar to that of eucapnia Respiratory rate increases slightly when Pa CO2 approaches values well above eucapnia (Fig 35-2) The intensity of respiratory effort (respiratory drive) increases progressively as a function of PCO2 This response is evident even in hypocapnic range The response slope increases progressively with increasing CO2 stimuli, reaching its maximum in the vicinity of eucapnic values (see Fig 35-2) There is no fundamental difference in the response to CO2 between various ventilator modes Above eupnea, the slope of the response does not differ significantly with that observed during spontaneous breathing, suggesting that mechanical ventilation per se does not considerably modify the sensitivity of respiratory system to CO2 During sleep (or sedation), the response of respiratory motor output to CO2 differs substantially from that during wakefulness, secondary to loss of the suprapontine neural input to the medullary respiratory controller.10,17 In ventilated sleeping subjects, a decrease in Pa CO2 by a few millimeters of mercury causes apnea.10 Respiratory rhythm is not restored until Pa CO2 has increased significantly above eupneic levels The difference between eupneic Pa CO2 and Pa CO2 at apneic threshold, referred to as CO2 reserve,18 depends on several factors (see Response of Respiratory Motor Output to Chemical Stimuli—Chemical stimuli and unstable breathing) This reserve determines the propensity of an individual to develop breathing instability during The effects of mechanical ventilation on the response of respiratory motor output to stimuli other than CO2 have not been studied adequately In a steady state during wakefulness, the effects of oxygen (O2) and pH on breathing pattern are similar qualitatively to that observed with CO2: Changes in O2 and pH mainly alter the intensity of patient effort, whereas respiratory rate is affected considerably less.5,12 There is no reason to expect a different response pattern during mechanical ventilation Indeed, this is the case regarding the hypoxic response in normal conscious subjects ventilated in assist-control mode during eucapnia.20 Indirect data also revealed that during eucapnia, the sensitivity of respiratory motor output to hypoxia was not modified by mechanical ventilation.20 During mild hypocapnia, however, the response was attenuated, whereas at moderate hypocapnia (end-tidal PCO2 approximately 31 mm Hg) the response was negligible The latter observations may be relevant clinically because ventilated patients not always keep Pa CO2 at eucapnic levels and can become hypocapnic.16 CHEMICAL STIMULI AND UNSTABLE BREATHING The response pattern of respiratory motor output to CO2 during sleep is relevant to the occurrence of periodic breathing in mechanically ventilated patients Studies indicate that this breathing pattern might increase the morbidity and mortality of critically ill patients because it can cause sleep fragmentation and patient–ventilator dyssynchrony.21–23 Sleep deprivation may cause serious cardiorespiratory,24,25 neurologic,26,27 immunologic, and metabolic consequences.28–31 The following is a brief review of the factors that can lead to unstable breathing In a closed system governed mainly by chemical control (such as occurs during sleep or sedation), a transient change in ventilation at a given metabolic rate (ΔV˙ initial) will result in a transient change in alveolar gas tensions This change is sensed by peripheral and central chemoreceptors, which, after a variable delay, exert a corrective ventilatory response (ΔV˙ corrective) that is in the opposite direction to the initial perturbation32,33 (Fig 35-3) The ratio of ΔV˙ corrective to ΔV˙ initial defines the loop gain of the system.32 Loop gain is a dimensionless index that is the mathematical product of three types of gains: plant gain (the relationship between the change in gas tensions in mixed pulmonary capillary blood and ΔV˙ initial), feedback gain (the relationship between gas tensions at the chemoreceptor level and those at the mixed pulmonary capillary level), and controller gain (the relationship between ΔV˙ corrective and the change in gas tensions at the chemoreceptor level) (Fig 35-3) Loop gain has both a magnitude and a dynamic component.32,33 In this 808 Part IX Physiologic Effect of Mechanical Ventilation Gplant TABLE 35-1: EFFECTS OF MECHANICAL VENTILATION ON GAIN FACTORS AND GAIN CHANGES FRC ↑ V/Q ↓ ↔ ↑ VD/VT ↓ ↔ ↑ PaCO2 ↓ ↔ ↑ CO ↓ ↔ ↑ Metabolic rate ↓ ↔ ↑ ΔVinitial ΔPCCO2, ΔPCO2 Gfeedback Mixing ↓ ↔ ↑ Circulatory delay ↓ ↔ ↑ Loop Gain (ΔVcorrective /ΔVinitial) ΔVcorrective Diffusion delay ↔ ΔPchCO2, ΔPchO2 Gcontroller Chemosensitivity ↔ Pmus ↓ ↔ ↑ Ers ↓ ↔ ↑ Rrs ↓ ↔ ↑ Paw ↑ FIGURE 35-3 Schematic of the variables that determine the propensity of an individual to develop periodic breathing in a closed system dominated by chemical feedback Loop gain is the product of three gains: ˙ (the plant, feedback, and controller Instability occurs when ΔV corrective ˙ (the transient final response) is 180 degrees out of phase with ΔV initial ˙ ˙ /ΔV is greater than Mechanical initial perturbation) and ΔV corrective initial ventilation, by affecting almost all variables of the system (↑, increase; ↔, no change; ↓, decrease), may change both the magnitude and the dynamic component of loop gain and thus the propensity of an individual to develop periodic breathing CO, cardiac output; ΔPCCO2 and ΔPCO2, the difference in partial pressures of CO2 and O2 in mixed pulmonary capillary blood, respectively; ΔPchCO2 and ΔPchO2, the difference in partial pressure of CO2 and O2 at chemoreceptors (peripheral and central), respectively; Ers and Rrs, elastance and resistance of respiratory system, respectively; FRC, functional residual capacity; LG, Gplant, Gfeedback, and Gcontroller, loop, plant, feedback, and controller gains, respectively; PaCO alveolar partial pressure of CO2; Paw, airway (ventilator) pressure; Pmus, pressure developed by respiratory muscles; V Q, ventilation–perfusion ratio; VD/VT, dead-space fraction system, instability occurs when the corrective response is 180 degrees out of phase with initial disturbance (dynamic component) and loop gain is greater than (magnitude component) This instability leads to fluctuation in chemical stimuli, namely, PCO2 If PCO2 reaches the apneic threshold, apnea occurs Positive-pressure breathing exerts multiple effects on loop gain by influencing almost all the factors that determine plant, feedback, and controller gains The effects are complex and at times opposing and variable (Table 35-1; see also Fig 35-3) Nevertheless, the effect of mechanical ventilation on controller gain exerts the most powerful influence on the propensity to develop breathing instability.8,19,21,23 The magnitude and direction of the change in controller gain depends on the ventilator mode, the level of assistance, the mechanics Gain Factors (Influence) Ventilator Effect* Lung volume (stabilizing) ↑ ↓Gplant Cardiac output (destabilizing) ↓ ↑Gplant, ↑Gfeedback Thoracic blood volume (destabilizing) Paw response to Pmus (destabilizing) Alveolar PCO2 (stabilizing) ↓ ↑Gfeedback ↑ ↑Gcontroller ↓ ↓Gplant Alveolar PO2 (stabilizing) ↑ ↓Gplant, ↓Gcontroller Respiratory elastance (destabilizing) ↓ ↑Gcontroller Gain Change Abbreviations: ↓, decrease; ↑, increase; Paw, airway pressure; Pmus, respiratory muscle pressure *Mechanical ventilation may also exert opposite effects on the various gain factors of the respiratory system, and the Pmus waveform (see the section Interactive Effects of Patient-Related Factors and Ventilator on Control of Breathing).8,16,19,21 Disease states as well as medications (e.g., sedatives) also may interfere with the effects of mechanical ventilation on loop gain For example, positive-pressure ventilation may increase or decrease cardiac output, causing corresponding changes in circulatory delay depending on cardiac function and intravascular volume (see Chapter 36).34–37 It has been shown that nocturnal mechanical ventilation in patients with congestive heart failure decreases the frequency of Cheyne-Stokes breathing, presumably by causing an increase in cardiac output secondary to afterload reduction.38–40 Sedatives at moderate doses, commonly used in ventilated patients, decrease considerably the loop gain, partly mitigating the effect of mechanical ventilation on controller gain and thus promote ventilatory stability.41 In addition to CO2, O2 and pH can play a key role in producing unstable breathing in ventilated patients during sleep (or sedation) It is well known that hypoxia, acting via peripheral chemoreceptor stimulation, decreases Pa CO2 The result reduces the plant gain (stabilizing influence); for a given change in alveolar ventilation, Pa CO2 will change less when baseline Pa CO2 is low than when it is high.18 Hypoxia, however, increases the controller gain to a much greater extent42 because the slope of ventilatory response to CO2 below eupnea increases,12 a highly destabilizing influence.32,33 Similar principles apply if pH is considered as a chemical stimulus; acidemia decreases the plant gain (lowers Pa CO2) and increases, to a much lesser extent, the controller gain.18,42 During mechanical ventilation, the propensity to unstable breathing in the face of changing O2 and pH stimuli depends on a complex interaction between the effects of these stimuli and mechanical ventilation on plant, feedback, and controller gains (Fig 35-4; see also Table 35-1) Chapter 35 Effects of Mechanical Ventilation on Control of Breathing 809 Metabolic acidosis VT (I) Pm 10 (cm H2O) Edi (a.u.) 40 CO2 reserve = –7.1 mm Hg PETCO2 (mm Hg) A Metabolic alkalosis VT (I) Pm (cm H2O) 10 ∫Edi (a.u.) CO2 reserve = –3.4 mm Hg 40 PETCO2 (mm Hg) B Hypoxia VT (I) Pm 10 (cm H2O) Edi (a.u.) 40 CO2 reserve = –3.4 mm Hg PETCO2 (mm Hg) C FIGURE 35-4 Tidal volume (VT), airway pressure (Pm), integrated diaphragmatic electrical activity (Edi, arbitrary units), and partial pressure of end-tidal CO2 (PETCO2) in a tracheostomized dog during non–rapid eye movement sleep without and with pressure-support ventilation at a pressure level that caused periodic breathing (A) At a background of hours of metabolic acidosis (pH 7.34, HCO3− 16 mEq/L, Pa CO2 30 mm Hg) (B) At a background of hour of metabolic alkalosis (pH 7.51, HCO3− 35 mEq/L, Pa CO2 44 mm Hg) (C) During hypoxia (PaO2 47 mm Hg, Pa CO2 31 mm Hg) At a background of metabolic acidosis, CO2 reserve was quite high; consequently, the pressure level that caused periodic breathing (20 cm H2O) was significantly higher than the corresponding values (approximately 10 cm H2O) during metabolic alkalosis or hypoxia Hyperventilation during spontaneous breathing was similar during metabolic acidosis and hypoxia (similar stabilization influence via a decrease in plant gain secondary to low Pa CO2), indicating that the destabilizing influence of hypoxia was caused by an increase in controller gain (hypoxic increase in the slope of CO2 below eupnoea) (Used, with permission, from Dempsey et al J Physiol 2004;560:1–11, based on data from Nakayama H, Smith CA, Rodman JR, et al Effect of ventilatory drive on carbon dioxide sensitivity below eupnea during sleep Am J Respir Crit Care Med 2002;165:1251–1260.) 810 Part IX Physiologic Effect of Mechanical Ventilation Operation of Chemical Feedback PET CO2 (mm Hg) 20 Flow –1 (L s ) 70 Paw (cm H2O) The ventilator mode is a major determinant of driving pressure for flow and thus arterial blood gases Before discussing the operation of chemical feedback, it is useful to review briefly the functional features of three main modes of assisted ventilation, namely, assist-control ventilation (ACV), pressure-support ventilation (PSV), and proportional-assist ventilation (PAV) (for detailed descriptions, see Chapters 6, 8, and 12) Figure 35-5 shows the response of the ventilator to respiratory effort in a representative subject ventilated with each mode in the presence and absence of CO2 challenge.16 With CO2 challenge, Paw decreases with ACV, it remains constant with PSV, and it increases with PAV Pressure-time product of inspiratory muscle pressure (PTP-PmusI) is an accurate index of the intensity of inspiratory effort.43 With ACV, the ratio of V T to PTP-PmusI per breath (neuroventilatory coupling) decreases with increasing Pmus; the ratio is largely independent of inspiratory effort with PAV With PSV, V T/ PTP-PmusI per breath may change in either direction with increasing Pmus, depending on factors such as the level of pressure assist and cycling-off criterion, change in Pmus, and mechanics of the respiratory system With PSV, in the absence of active termination of pressure delivery (with expiratory muscle contraction), the ventilator delivers a minimum V T , which may be quite high, depending on the pressure level, mechanics of the respiratory system, and cycling-off criterion.19 Assume that in a ventilated patient Pa CO2 drops because of an increase in the set level of assistance or decrease in metabolic rate and/or VD/VT ratio.44 During wakefulness, patients will react to this drop by decreasing the intensity of their inspiratory effort, whereas the breathing frequency will remain relatively constant (see “Response of Respiratory Motor Output to Chemical Stimuli,” above) The extent to which a patient is able to prevent respiratory alkalosis via operation of chemical feedback depends almost exclusively on the relationship between the intensity of patient inspiratory effort and the volume delivered by the ventilator (i.e., VT/PTP-PmusI) Similarly, if Pa CO2 increases (decrease in assistance level, increase in metabolic rate and/or VD/VT ratio), the patient will increase the intensity of inspiratory effort and, to much lesser extent, respiratory frequency Thus, VT/PTP-PmusI per breath is critical for the effectiveness of chemical feedback to compensate for changes in chemical stimuli (Pa CO2) For given respiratory system mechanics, VT/PTP-PmusI is heavily dependent on the mode of support Thus, the effectiveness of chemical feedback in compensating for changes in chemical stimuli should be mode-dependent Modes of support that permit the intensity of patient inspiratory effort to be expressed on ventilator-delivered volume improve the effectiveness of chemical feedback in regulating Pa CO2 and particularly in 35 10 Pes (cm H2O) Volume (L) –2 –2 10 –10 –20 A B 5s C D 5s E F 5s FIGURE 35-5 End-tidal carbon dioxide tension (PETCO2), airway pressure (Paw), flow (inspiration up), volume (inspiration up), and esophageal (Pes) pressure in a representative subject during proportional-assist ventilation (A, B), pressure-support ventilation (C, D), and volume-control ventilation (E, F) in the absence (A, C, E) and presence (B, D, F) of CO2 challenge With CO2 challenge, Paw decreases with assist-control ventilation (the ventilator antagonizes patient’s effort); it remains constant with pressure-support ventilation (no relationship between patient effort and level of assist); and it increases with proportional-assist ventilation (positive relationship between effort and pressure assist) (Used, with permission from Mitrouska J, Xirouchaki N, Patakas D, et al Effects of chemical feedback on respiratory motor and ventilatory output during different modes of assisted mechanical ventilation Eur Respir J 1999;13:873–882.) Chapter 35 0.8 VT/PTP-PmusI (L/cm H2O/s) + 0.6 + 0.4 * 0.2 * PAV PS AVC FIGURE 35-6 Ratio (mean ± SD) of tidal volume to pressure–time product of inspiratory muscles (VT/PTP-PmusI) in normal, conscious subjects ventilated with three modes of assisted ventilation in the absence and presence of CO2 challenge (inspired CO2 concentration increased in small steps until intolerance developed) Open and closed bars represent zero and final (highest) concentration of inspired CO2, respectively AVC, assist-volume control; PAV, proportional-assist ventilation; PS, pressure-support ventilation Asterisk indicates significant difference from the value without CO2 challenge Plus sign indicates significant difference from the corresponding value with PAV With each mode, subjects were ventilated at the highest comfortable level of assistance (corresponding to 80% reduction of patient resistance and elastance with PAV, 10 cm H2O of pressure support, and 1.2-L tidal volume with AVC) With CO2 challenge, VT/PTP-PmusI, decreased significantly when the subjects were ventilated with PS and AVC, but it remained relatively constant with PAV Without CO2 challenge, VT/PTP-PmusI was significantly higher with PS and AVC than with PAV This response pattern caused severe respiratory alkalosis with PS and AVC (PETCO2 decreased to approximately 22 mm Hg with both modes) but not with PAV (PETCO2 approximately 30 mm Hg) Unlike with PS and PAV, subjects ventilated with AVC could not tolerate high values of PETCO2 (final PETCO2 was approximately 7, 11, and 13 mm Hg higher than baseline eupnea, respectively, with AVC, PS, and PAV) (Based on data from Mitrouska et al.16) preventing respiratory alkalosis In normal conscious subjects receiving maximum assistance on the three main ventilator modes,16 the ability of the subject to regulate Pa CO2 depends on the operational principles of each mode, specifically in terms of VT/PTP-PmusI (Fig 35-6) At all levels of CO2 stimulation, preservation of neuroventilatory coupling increased progressively from ACV to PSV to PAV; the ability of subjects to regulate Pa CO2 followed the same pattern.16 Neurally adjusted ventilatory assist (NAVA) is a new mode of support that, similar to PAV, uses patient effort to drive the ventilator.45–47 The electrical activity of the diaphragm is obtained with a special designed esophageal catheter and serves as a signal to link inspiratory effort to ventilator pressure (see Chapter 13) Because neuroventilatory coupling is preserved, the principles described above also apply to NAVA.46,47 During sleep or sedation, the tendency to develop hypocapnia with ACV and PSV (see Chapter 57 for the effects of mechanical ventilation on sleep) may have serious consequences because a drop of a few millimeters of mercury in Pa CO2 leads to apnea and periodic breathing.8,19 Thus, excessive assistance with ACV and PSV promotes unstable breathing secondary to impaired neuroventilatory coupling; Effects of Mechanical Ventilation on Control of Breathing 811 controller gain remains high in the face of low inspiratory effort (Fig 35-7) Unstable breathing, however, during sleep secondary to mechanical ventilation may be prevented or attenuated with PAV and NAVA that does not guarantee a minimum VT 8,19,46,47 Modes that decrease the volume delivered by a ventilator in response to any reduction in the intensity of patient effort enhance breathing stability and may be associated with better sleep quality.48 Nevertheless, if the assist setting during PAV or NAVA is such that controller gain increases considerably, and the inherent loop gain of the patient is relatively high, the patient will be at risk of developing unstable breathing.23,33,41,49,50 These principles may be altered by disease states and therapeutic interventions Although little is known about the interaction between disease states and mechanical ventilation on control of breathing, two examples help in illustrating the point First, in conscious patients with sleep apnea syndrome, a drop in Pa CO2 because of brief (40 seconds) hypoxic hyperventilation resulted, contrary to healthy subjects, in significant hypoventilation and triggering of periodic breathing in some patients.51 This hypoventilation was interpreted as evidence of a defect (or reduced effectiveness) of short-term poststimulus potentiation, a brainstem mechanism that promotes ventilatory stability.51 In this situation, a level of assistance that causes a significant decrease in Pa CO2 may promote unstable breathing in awake patients with sleep apnea syndrome, a situation closely resembling that observed during sleep Second, studies in ventilated critically ill patients have shown that when awake patients are unable to increase VT appropriately as a result of the mode used (i.e., PSV), they increase respiratory rate in response to a chemical challenge.52 Behavioral feedback, however, may underlie this response pattern In sedated patients with acute respiratory distress syndrome (in whom behavioral feedback is not an issue) receiving PSV, considerable variation in Pa CO2 elicited a steady-state response limited to the intensity of breathing effort, a response pattern similar to that observed in normal subjects.9,16 Neuromechanical Feedback INTRINSIC PROPERTIES OF RESPIRATORY MUSCLES For a given neural output, Pmus decreases with increasing lung volume and flow, as dictated by the force-length and force-velocity relationships of inspiratory muscles, respectively.53 Therefore, for a given level of muscle activation, Pmus should be smaller during mechanical ventilation than during spontaneous breathing if pressure provided by the ventilator results in greater flow and volume It has been shown in healthy subjects ventilated with PSV that, compared with spontaneous breathing, the relationship between electrical activity (Edi) and pressure-time product of diaphragm (PTPdi) is shifted to the left; thus, at any given level of Edi, PTPdi is reduced.54 812 Part IX Physiologic Effect of Mechanical Ventilation Chin EMG C3/A2 C4/A1 EOG(R) EOG(L) Rib cage Abdomen Volume Flow PETCO2 Paw A B C Chin EMG C3/A2 C4/A1 EOG(R) EOG(L) Rib cage Abdomen Volume Flow PETCO2 Paw D 30 s FIGURE 35-7 Polygraph tracings in a healthy subject during non-rapid eye movement sleep with and without pressure-support ventilation (A) Spontaneous breathing with continuous positive airway pressure (CPAP) (B) to (D) Pressure support of 3, 6, and cm H2O, respectively Periodic breathing with central apneas developed with pressure support of cm H2O C3/A2 and C4/A1, electroencephalogram channels; EMG, electromyogram; EOG, electrooculogram (right [R] and left [L]); Paw, airway pressure; PETCO2, end-tidal PCO2 (Used, with permission, from Meza, et al Susceptibility to periodic breathing with assisted ventilation during sleep in normal subjects J Appl Physiol 2003;167:1193–1199.) The influence and consequences of mechanical feedback during mechanical ventilation have not been studied satisfactorily It is possible that this type of feedback is of clinical significance in patients with dynamic hyperinflation (high end-expiratory lung volume), high ventilatory requirements (requirements for high flow and volume), and/or impaired neuromuscular capacity REFLEX FEEDBACK The characteristics of each breath are influenced by various reflexes that are related to lung volume or flow and mediated, after a latency of a few milliseconds, by receptors located in the respiratory tract, lung, and chest wall.5,6 Mechanical ventilation may stimulate these receptors by changing flow and volume In addition, changes in 1548 Index Positive-predictive value, 1322 Positive-pressure chamber, Jourdanet, 31, 32f Positive-pressure mask, early, 30, 30f Positive-pressure valve, Bennett, 33, 33f Positive-pressure ventilation (PPV) See also specific types on fluid balance, 1460–1461 history of in operating room, 22–23 in physiology laboratory, 22, 26f, 27f initiation of, fluid resuscitation during, 843 noninvasive (See Noninvasive positivepressure ventilation (NIPPV)) vs spontaneous breathing, on heart–lung interactions with ventilation, 830–833 Post, 16 Postextubation distress, 1353–1364 causes of other, 1356 upper airway obstruction in, 1355–1356, 1355f classification of, 1354–1355 consequences of, 1357–1358, 1357t definition of, 1354 incidence of, 1353–1354, 1354t pathophysiology of, 1356–1357, 1357f predictors of, 1358–1364 cough, 1363 cuff-leak test, 1359–1362, 1360f, 1360t neurologic assessment, 1363–1364 secretions, 1362–1363, 1362f spontaneous ventilation, sustaining, 1358 weaning predictor tests, 1358–1359 Postextubation laryngeal edema, 905f, 911, 1355–1356, 1355f treatment of after translaryngeal intubation, 925 epinephrine in, 1364 glucocorticoids in, 1364–1365 Postextubation sore throat, 910 Postextubation stridor, 911 avoiding, 930–931 management of, 925 in neonates and children, 589–590, 590f Postextubation upper airway obstruction, 1355–1356, 1355f Postoperative hypoxemia, positive endexpiratory pressure for, 281–282 Postoperative patients noninvasive positive-pressure ventilation in, 459–460 pulmonary complications in, 604, 605t–606t from mechanical ventilation in asthma and COPD, 620 respiratory failure in, 115–118 after cardiac surgery, 117, 117f from atelectasis, 115–116, 116f, 117f definition of, 115 early extubation in, 118 etiology of, 115, 116t, 117f mechanical ventilation for, 124–125 preoperative assessment and risk factors for, 116–117 Posttest probability, 1157 vs pretest probability, 1323 for weaning-predictor test, 1324, 1324f on successful outcome, 1324 Posttraumatic stress disorder (PTSD) after critical illness, 1509 after mechanical ventilation, 1268 in ventilated, 1260, 1264 Postural changes, on gas exchange in acute lung injury and ARDS, 858 in pneumonia, 859 Posture, patient, fighting the ventilator from, 1248 Power source, for anesthesia ventilators, 604 Precision, 1141 Predetermined, 52–53 Prednisolone, as bronchodilator, 1421–1422 Prednisone, as bronchodilator, 1421–1422 Prehospital setting continuous positive airway pressure for cardiogenic pulmonary edema in, 457 mechanical ventilation in resuscitation in, 657–658, 658f positive end-expiratory pressure for, 284 Preoxygenation before intubation, noninvasive positivepressure ventilation for, 462 before surgery, 662 for tracheal intubation, 879 Pressor response, from endotracheal tube placement, 899 Pressure, 45–46 elastic recoil, 46 in operator interface as trigger variable, 75–76, 76t as target variable, 77–79, 78f–80f inspiratory pressure, 77–78, 78f, 79f Pmax, 78 rise time, 78–79, 80f Pressure adjustment, automatic feedback, artificial airway geometry in, 408–409, 408f Pressure- and flow-targeted breath, feedback control of, 404–406 dual control breath to breath in, 404–406, 405f tidal volume modes enhancing, 406 dual control within a breath in, 404 Pressure assist-control ventilation (PACV), in general anesthesia, 602t Pressure augmentation modes, 142–143 Pressure-controlled ventilation (PCV), 141–142, 228–243 for acute respiratory distress syndrome, 713 vs assist-control ventilation, 164 assisted, 228, 229f characteristics of, specific, 228–235 input parameters in, 230 mean airway and alveolar pressure in, 230–231, 231f modes in, 228–229 output variables in, 231–235 alveolar ventilation, 232–233 inspiratory flow, 233–235, 234f–236f intrinsic PEEP, 232, 232f minute ventilation, 232, 233f tidal volume, 231–232 physical principles in, 229–230 in children, 586 classification of, 228 control variables in, 46 definition of, 57 future of, 247 history of, 227 in neonates and infants, 583–584, 585 physiological effects of, 235–239 advantages of controlling airway pressure in, 229f, 235–237 assisted vs controlled ventilation in, 239 distribution of ventilation in, 234f, 235f, 237–238 positive end-expiratory pressure in, for speech with invasive positivepressure ventilation, 1285, 1286f time-cycled, 228 transpulmonary effective pressure in, vs flow-controlled ventilation, 228, 229f variants of airway pressure release ventilation in, 240–243 combined modes of, 242–243 exhalation valve opening in, 240 fundamentals of, 241–242 assisted pressure-controlled ventilation in, 239–240 Pressure-cycled ventilation, 228 Pressure cycling, in operator interface, 88 Pressure-preset mode, 141–142 Pressure-preset ventilation See Pressurecontrolled ventilation (PCV) Pressure-regulated volume control, 54, 54f, 143 Pressure-regulated volume-controlled ventilation (PRVCV), vs intermittent mandatory ventilation, 189–190 Pressure support, for weaning, 1338–1339 Pressure-support ventilation (PSV), 141–142, 199–219 bedside level pressure adjustment in, 217 breathing in, 50–51 in children, 586 closed-loop delivery in dual modes of, 217 knowledge-based systems for, 217–218 noisy pressure-support ventilation in, 218 predicting effect of, load estimation in, 218 definition of, 200, 200f epidemiology of, 200 in general anesthesia, 602t hemodynamic consequences of, 217 in neonates and infants, 585 for noninvasive ventilation, 219 vs other modes, 214–216 airway pressure release ventilation, 309 assist-control ventilation, 167–169, 214–215 intermittent mandatory ventilation, 186–188, 187f, 187t intermittent positive-pressure breathing, 214 neurally adjusted ventilatory assist, 216 proportional-assist ventilation, 215–216 synchronized intermittent mandatory ventilation, 215 patient–ventilator synchrony/asynchrony in, 208–214 asynchrony in, 208–209 at cycle initiation, 209–212 autotriggering in, 209f, 211 ineffective triggering in, 209–211, 209f inspiratory trigger delay in, 209 multiple cycles in, 210f, 211–212 Index inspiratory cycling-off or cycling to expiration in clinical detection of, 214 delayed expiration in, 211f–213f, 213 early cycling-off in, 209f–211f, 214 very prolonged inspiration in NIV in, 211f, 213–214, 213f synchrony in, 208 phases of, 200–201, 202t physiologic effects of, 204–207 breathing pattern in, 204–205, 205f distribution of ventilation and perfusion in, 206 endotracheal tube and demand valve in, 207 gas exchange in, 205–206 instrumental dead space in, 207 work of breathing and respiratory effort in, 206–207 on sleep, 207–208 trigger failure in, monitoring for, 1152, 1153f ventilators for, differences in, 201–204, 202t algorithms on efficacy of, 201–203, 203f–205f dedicated noninvasive ventilators in, 203–204 for weaning, 218–219 vs intermittent mandatory ventilation, 190, 191t with noninvasive ventilation, 219 Pressure-time product, 102, 102f Pressure-triggered synchronized intermittent mandatory ventilation, 177–179, 177f Pressure–volume change, in ventilator-induced lung injury, 1003–1004, 1005f Pressure–volume curve of moderately diseased lung, 496, 497f monitoring of, for lung protection, 1008f, 1011–1012 in tidal volume range, in proportional-assist ventilation, 339, 340f Pressure–volume swings, in ventilator-induced lung injury, 1004–1007, 1006f, 1007f Pressure–volume threshold, for edema and permeability alterations, 1003–1004, 1005f Pressurization, in pressure-support ventilation, 201 Pressurized metered-dose inhalers (pMDI) clinical use of, 1426 configuration of, 1427, 1428f with noninvasive ventilation, 1437–1439 techniques for, 1436, 1436t Pretest probability, 1157 vs posttest probability, 1323 Prevention See Protective strategies Priestley, 6–7, 9, 9f, 35 Probabilistic reasoning, 1157–1158 Probability conditional, 1323 posttest, 1157 on successful outcome, 1324 pretest, 1157 pretest vs posttest, 1323 for weaning-predictor test, 1324, 1324f Probability statement, 1323 Pro-brain natriuretic peptides (BNP), 1336 Procalcitonin, in ventilator-associated pneumonia, 1103 Productive work, 1272 Prone positioning for acute respiratory distress syndrome, 716–717, 716t, 717f, 721 for acute respiratory failure, on outcome arterial oxygenation in, 1174–1178, 1175f–1178f (See also Arterial oxygenation) mortality in, 1178–1179, 1179f, 1179t on gas exchange, 1169–1174 distribution of perfusion in acute respiratory failure, 1174 in normal lungs, 1173 distribution of ventilation in acute respiratory failure, 1173 in normal lungs, 1172 regional lung inflation, 1169–1172 in acute respiratory failure, 1170f, 1171, 1171f in normal lungs, 1170, 1170f ventilation–perfusion matching in, 1174 for lung protection, 1013–1014 Prophylactic positive end-expiratory pressure, 284–286, 285t Propofol, 1189, 1190t for asthma, severe, 734 for respiratory discomfort, 1276 for tracheal intubation, 889 Proportional-assist ventilation (PAV), 83, 85f, 143, 315–336, 411 basic principles and algorithms of, 315–317, 316f, 317f bedside adjustments in in intubated, 342–346 algorithm for, 342f fundamentals of, 342 immediate responses after transition to, 325f, 329f, 330f, 343–345, 343f, 344f initial ventilator settings in, 342–343 subsequent management and troubleshooting in, 335f, 337f, 342f, 345–346 in noninvasive applications, 341–342 commercial systems for, 333–334 definition of, 315, 316f equal vs unequal assist in, 346–347, 347f future of, 346 indications and contraindications for, 340–341 limitations of, 334–340 dynamic hyperinflation in, 324f, 325f, 329f, 335f, 337–339, 338f excessive alarming in, 339–340 leaks in, 330f, 336–337 pressure–volume relationship in tidal volume range in, 339, 340f respiratory mechanics values accuracy and stability in, 335–336 runaway phenomenon in, 324f, 334–335, 335f–337f ventilator response time in, 339 for neuromuscular disease, 768–769 vs other modes, 323–333 intermittent mandatory ventilation, 188–189 operational differences in, 316f, 323–324, 323f–325f 1549 operational differences in, physiological consequences of, 324–330 comfort in, 329 hemodynamic effects in, 329–330 levels of assist in, 318f, 324–326, 326f respiratory mechanics changes in, 328, 328f respiratory rate and, 325f, 328–329, 329f tidal volume and, 325f, 327f, 329 ventilatory demand changes in, 326–327, 327f physiologic differences in, clinical consequences of clinical outcomes in, 332–333, 333f patient management in, 316f, 322f, 325f, 330–332, 330f, 331f pressure-support ventilation, 215–216 physiologic principles of, 317–320 expected response in, 319 minute ventilation and pulmonary CO2 determinants in, without nonchemical drive sources, 318–319, 318f nonchemical drives on response to PAV in, 318f, 319–320 respiratory drive in, source of, 317–318 physiologic responses of, 320–323 respiratory muscle output in, 320 respiratory rate and breathing pattern in, 316f, 321–322, 322f responses during exercise in, 323 ventilation and partial pressure of CO2 in, 318f, 320–321 ventilatory instability in, 322–323 sedative use with, 341 for sleep improvement, 1302–1303, 1303f unknowns in, important, 346 on ventilatory instability, 322–323 Proportionality, 316 Prostacyclin (PGI2), in sodium balance, 1460 Prostaglandin E, in sodium balance, 1460 Proteasome 20S and 26S isoforms of, 1030, 1030f in ventilator-induced diaphragm atrophy, 1030, 1030f–1032f Protective strategies See also specific strategies; specific ventilation modalities for ventilator-induced diaphragm dysfunction intermittent diaphragmatic contractions in, 1036 pharmacologic, 1036–1037, 1037f ventilator, 1036, 1036f for ventilator-induced lung injury, 378, 1011–1017 hypercapnia in, 1017 lung mechanics improvement in, 1011–1014 noisy ventilation in, 1014 perfluorocarbons in, 1012–1013, 1013f pressure–volume curves in, 1008f, 1011–1012 prone position in, 1013–1014 surfactant in, 1012 pharmacologic interventions in, 1014–1017 for hormonal and metabolic pathways, 1016–1017 for inflammation, 1015–1016, 1015f for microvascular permeability, 1014–1015, 1014f strategies for, 495 1550 Index Proteoglycans, mechanical ventilation on, 603 Protocol vs usual care, in weaning, 1342–1344, 1344f Proton pump inhibitors, for ventilator-associated pneumonia prevention, 1111 Pseudobarotruma, 1043 Pseudomembranous tracheitis, from translaryngeal intubation, 907 Psychiatric morbidity, critical illness and, 1509 Psychological problems, in ventilated, 1259–1264 assessment of, 1259 delirium in, 1261–1263 depression in, 1263 diagnosis of, 1259 diagnostic and contextual challenges in, 1260–1261 epidemiology of, 1259 nonpharmacologic interventions for, 1264 posttraumatic stress disorder in, 1264 syndromes in, 1260 terminology for, 1260, 1260f Psychosis, ICU, 1301 Pulmonary afferents, dyspnea from, 1273 Pulmonary arterial hypertension (PAH), inhaled nitric oxide for, 1392t Pulmonary arterial pressure, overwedging in, 1147, 1148f Pulmonary artery catheter (PAC) for monitoring, 1154, 1155f for monitoring fluid therapy, 1467–1468 on survival, studies on, 1154, 1155f waveforms in, 1143 Pulmonary artery occlusion pressure (PAOP) monitoring of, in fluid therapy, 1467 transmural, in weaning failure, 1317 Pulmonary artery pressure, mean, in weaning failure, 1318, 1318f Pulmonary artery rupture, fighting the ventilator from, 1244–1245 Pulmonary aspiration, from endotracheal tube placement, 898 Pulmonary circulation, permissive hypercapnia on, 379 Pulmonary complications, postoperative, 604, 605t–606t, 620 Pulmonary edema in acute respiratory distress syndrome, 703, 704f cardiogenic hypoxemic and hypercapnic respiratory failure in, general ward noninvasive ventilation in, 795–796 noninvasive positive-pressure ventilation for, 455–457 positive end-expiratory pressure for, 283–284 fighting the ventilator from, 1244 high-altitude, inhaled nitric oxide for, 1392t negative pressure, postextubation, 912 noncardiogenic in acute respiratory distress syndrome, 701, 703, 704f definition of, 703 from upper airway obstruction, 120, 120f ventilation-induced microvascular permeability in, 998–1000, 999f–1000f pressure–volume threshold for, 1003–1004, 1005f Pulmonary embolism (PE), 985–987 diagnosis of, 985–986, 986f fighting the ventilator from, 1244 incidence and risk factors for, 985 prevention of, 987 risk stratification in, 986–987 Pulmonary function after acute respiratory distress syndrome, 1507–1508, 1508f mechanical ventilation on, 608, 610t Pulmonary hyperinflation, in severe asthma, 728–731, 729f, 730f, 731t Pulmonary hypertension inhaled nitric oxide for in cardiac surgery, 1393t in infants, 1394, 1396t–1397t perioperative, in infant congenital heart patients, 1394, 1396t–1397t permissive hypercapnia for, 386, 388 Pulmonary insufficiency, pathophysiology of, 684, 684f Pulmonary interstitial emphysema clinical manifestations of, 1043f, 1047f, 1049–1050, 1050f management of, 1055 Pulmonary resistance, volume-dependent changes on lung volume in, 824, 824f Pulmonary sepsis, permissive hypercapnia for, 386–387, 386f, 387f Pulmonary vascular resistance (PVR) after birth, 576 alveolar expansion on, 503 before birth, 576 determinants of, 576, 576t on lung volume in mechanical ventilation, 823–824, 824f Pulmonary vasoconstriction, hypoxic, 823 Pulmonary vasodilation, from oxygen breathing, 1066–1068, 1066f Pulse oximetry, in hypoxemia monitoring, 1153 Pulsus paradoxus, 824, 829, 830 Pumpless extracorporeal lung assist, 550–551 Q “Quad” coughing, 479 Quality-adjusted life-year (QALY), 1491 Quality of life health-related, after critical illness, 1502, 1503f–1505f noninvasive positive-pressure ventilation on, 465–466, 465f Quaternary ammonium-containing muscarinic antagonists, 1421 Quénu, 23 R Random error definition of, 1140, 1140f sources of human error in, 1146, 1147f noise in, 1144–1145, 1144f–1147f nonlinearity in, 1145–1146 Range errors, 1143, 1143f Ranitidine, for ventilator-associated pneumonia prevention, 1111 Rapid eye movement (REM) sleep, 1293, 1294f, 1293 Rapid sequence induction, of anesthesia, 879–880, 879f, 879t Rapid-sequence intubation, 659 Reactive oxygen species, in oxygen toxicity, 1075–1079, 1077f, 1078f Reasoning deterministic, 1158 physiologic (causal), 1158 probabilistic, 1157–1158 Rebound pulmonary vasospasms, after inhaled nitric oxide, 1399 Recoil pressure, 259 Recording, fidelity of, 1146–1147, 1147f, 1148f Recovery and repair mechanisms, permissive hypercapnia on epithelial wound repair in, 384 extracellular fluid clearance in, 383–384 Recruitment maneuvers for acute respiratory distress syndrome future directions and research on, 721 studies of, 715–716 in anesthesia and surgery, 607f, 612–613, 612f, 614t consolidating benefit after, 711 effectiveness of, 711–712, 711t, 712f high pressure in, sustaining, 711–712 physiology of, 710–711, 710f, 711f in ventilator-induced lung injury, 710–711, 710f, 710t, 711f Recurrent laryngeal nerve injury, during tracheotomy, 947 Reference standard, choice of, 1157 Reflex feedback, in control of breathing with ventilation, 812–815, 813f–815f Regional lung inflation See Lung inflation, regional Regnault, 7, 8f Regulator, vacuum adjustable, 1225 Rehabilitation during and after ICU, on outcomes, 1511–1513, 1512f noninvasive positive-pressure ventilation for in COPD, 471–472 Reintubation after unplanned extubation, 1368 definition of, 1354, 1354t incidence of, 1354, 1354t reduction of, interventions for, 1365–1366, 1366f in ventilator-associated pneumonia, 1096 Reiset, 7, 8f Relative humidity, 1200 Remifentanil, 1185, 1186t REM rebound, 1295, 1301 Renal blood flow, positive-pressure ventilation on, 979 Renal complications, 978–979, 979f Renal system, positive end-expiratory pressure on, 269–270 Renin–angiotensin system, in ventilatorinduced lung injury, 1016 Replacement fluids, 1463–1464, 1464t Reproducibility, 1141 of standard predictor of weaning outcome, 1314f, 1335–1336 Residents’ knowledge, of mechanical ventilation, 1148–1149, 1149t Index Resistance, 46, 53 airflow, in translaryngeal intubation, 909 alveolar, lung volume on, 824, 824f ohmic, 259 pulmonary vascular (See Pulmonary vascular resistance (PVR)) Resistance, airway assessment of, 259, 259f on flow profile, in pressure-controlled ventilation, 235, 235f high, common causes of, 1273, 1273t in humidification, 1205 increased expiratory, on respiratory mechanics in COPD, 742, 742f increased inspiratory, on respiratory mechanics in COPD, 741–742, 742f patient circuit, 70–71 pediatric, 575 positive end-expiratory pressure on, 260, 264–265 respiratory impedance in, correcting, 1273–1274, 1273t volume-dependent changes in, on lung volume, 824, 824f Resistance, lung, in weaning failure, 1310– 1311, 1310f Respiration, shallow, 106 Respirator modern, history of, 35 tank early, 20, 21f Emerson’s early, 21, 26f Respirator lung syndrome, early history of, 36 Respirator room, negative-pressure, early, 20–21, 24f Respiratory acidosis, in severe asthma, 733 Respiratory alkalosis from patient–ventilator interactions, 154 from ventilator-supported patient transport, 670 Respiratory alternans, 106, 107f Respiratory centers, 598 Respiratory control system, 805 Respiratory depression, from oxygen breathing, 1066–1068, 1066f Respiratory discomfort, in ventilated, 1267–1277 approach to, 1273–1277 in dyspnea with care activities, 1274 respiratory drive reduction in, 1273 respiratory impedance in, correcting increased with excessive resistance, 1273–1274, 1273t with fighting the ventilator, 1274 with low compliance, 1274 ventilator settings in, 1274–1276 in chronically ventilator-dependent patients, 1276 control mode on, 1274f, 1275 level of ventilator support in, 1274–1275, 1274f positive end-expiratory pressure level on, 1275 rate of inflation on, 1275 studies on, 1274 ventilator adjustments on, unwanted effects of, 1276 assessment of neurophysiologic surrogates in, 1269 other sensations in, 1269 patient questioning in, 1268, 1268t physical signs in, 1268–1269 dyspnea in, 1269–1273 (See also Dyspnea, in ventilated) epidemiology of, 1277 future of, 1277 occurrence and sequelae of, 1267–1268 unknowns in, important, 1277 Respiratory distress signs of, 102–108 accessory and expiratory muscle recruitment in, 105, 105f asynchrony, paradox, and respiratory alternans in, 106, 107f cardiovascular, 107–108 clinical manifestations in, 102–103 diaphoresis in, 104 energy expenditure in, 102 facial, 103–105, 104f, 105f inspiratory pressure-time product in, 102, 102f intercostal recessions in, 106 moaning and grunting in, 104 mouth in, 103, 104f nasal flaring in, 104 nonuniform presentation in, 108 physical examination in, 106–107 pressure-time product in, 102, 102f respiratory effort in, 102–103, 103f respiratory muscle work in, 102–103, 103f respiratory rate measurement in, 105–106, 106t shallow respiration in, 106 tachypnea in, 106 tracheal tug in, 106, 107f sudden, on ventilation, 1240t ventilation for reversal of, 121–122 Respiratory Distress Observation Scale (RDOS), 1268–1269 Respiratory distress syndrome (RDS), in neonates and infants, 578–579 high-frequency oscillatory ventilation for, 503, 503t, 586 permissive hypercapnia for, 392, 392f pulmonary therapies for, 503, 503t surfactant in, 1375 Respiratory drive respiratory discomfort from reduction in, 1273 sources of, 317–318 Respiratory effort, in pressure-support ventilation, 206–207 Respiratory failure See also Acute respiratory failure (ARF); Chronic respiratory failure (CRF) artificial organs for, 543–545 (See also Extracorporeal carbon dioxide removal (ECCO2R)) hypercapnic, 113–115, 145 clinical presentation of, 110f, 115 pathophysiology of, 113 physiologic effects of, 113–115, 114f hypoxemic, 108–113, 145 clinical presentation of, 112–113, 112f, 113t 1551 pathophysiology and etiology of, 108–110, 108t, 109f, 110f, 256 physiological effects of, 110–112, 110f, 111f positive end-expiratory pressure on, 256–257, 258t hypoxic, ventilator settings for, 145–151 (See also Hypoxic respiratory failure, ventilator settings for) impending, 108 negative-pressure ventilation for, 425–426, 426t postoperative, 115–118 after cardiac surgery, 117, 117f from atelectasis, 115–116, 116f, 117f definition of, 115 early extubation in, 118 etiology of, 115, 116t, 117f preoperative assessment and risk factors for, 116–117 ventilation for, 124–125 in preterm infants, inhaled nitric oxide for, 1394, 1396t therapeutic endpoints with, 144–145 Respiratory frequency in chronic obstructive pulmonary disorder, 744 in ventilator-induced lung injury, 708 Respiratory impedance, correcting increased with excessive resistance, 1273–1274, 1273t with fighting the ventilator, 1274 with low compliance, 1274 Respiratory mechanics, 45–46, 47f See also specific types assessment of, 259, 259f cardiovascular function and, 822 in chronic obstructive pulmonary disease dynamic hyperinflation and intrinsic PEEP in, 742–743, 743f, 744f expiratory airway resistance increase in, 742, 742f inspiratory airway resistance increase in, 741–742, 742f dissociation of, 545, 545f positive end-expiratory pressure on, 259–265 in acute respiratory distress syndrome, 260f, 261f, 263–265 in acute respiratory distress syndrome, on lung volume, 258t, 260–263, 261f in anesthetized subjects, 259–260, 260f assessment of, 259, 259f in chronic obstructive pulmonary disorder, 259f, 260f, 265 diaphragmatic activation in, 265 in proportional-assist ventilation, accuracy and stability of values of, 335–336 in weaning failure, 1310–1311, 1310f Respiratory motor output fighting the ventilator from with elevated output, 1247–1248 with inadequate output, 1247 proportional-assist ventilation on, 320 Respiratory motor output response, in breathing control with ventilation carbon dioxide stimulus in, 806–807, 807f chemical stimuli, and unstable breathing, 807–808, 808f, 808t.809f chemical stimuli in, other, 807 Respiratory muscle cells, 811–812 1552 Index Respiratory muscle fatigue in chronic obstructive pulmonary disease, 743–744 in weaning failure, 1312–1316, 1315f–1317f Respiratory muscle pressure (Pmus), 805 waveform characteristics in, 806f, 817, 817f Respiratory muscles assist-control ventilation on, 161–162 inspiratory muscle effort in, 160–161 in chronic obstructive pulmonary disease muscle fatigue in, 743–744 muscle weakness in, 743 contraction of, anesthesia and surgery on, 598–599 feedback of, in respiratory reflexes, 353, 354f negative-pressure ventilation on, 422, 423f in respiratory distress, 102–103, 103f resting of, 154 training of, for weaning, 1345–1346 weakness of, in COPD, 743 in weaning failure, 1313–1316, 1315f–1317f Respiratory pump, 684, 684f failure of, long-term treatment for, 684, 684f (See also Home mechanical ventilation (HMV)) in general anesthesia, 601, 602t–603t Respiratory rate See also specific types of ventilation for acute lung injury and hypoxic respiratory failure, 149–150 in asthma, severe, 729f, 730f, 731–732, 731f entrainment of, to ventilator rate, 815 in health and disease, 106, 106t measurement of, 105–106 proportional-assist ventilation on, 316f, 321–322, 322f Respiratory reflexes, 352–354, 354f chemoreceptors in, 353, 354f joint receptors in, 353, 354f lung feedback in, 352–353, 354f respiratory muscle feedback in, 353, 354f sedation and analgesia in, 354 upper airway feedback in, 353–354, 354f Respiratory sinus arrhythmia, 843 Respiratory stimulation, from oxygen breathing, 1066–1068, 1066f Respiratory syncytial virus pneumonia, pediatric, 580 Respiratory system equation of motion for, 46, 53 physiology and components of, 684, 684f as single flow resistance and elastic chamber, 45–46, 47f Respiratory system mechanics, on control of breathing, with ventilation, 816–817, 816f Respiratory tract, upper See Upper airway Respiratory trauma, mechanical ventilation for, 124–125 Response, to therapy, 1160 See also specific therapies Response time, 48, 1143 Restrictive thoracic diseases See also specific types negative-pressure ventilation for, 426–427 noninvasive positive-pressure ventilation for, 455, 463–464, 464t patient selection for, 467–468, 467t timing of, 468–469 Resuscitation, mechanical ventilation in, 655–664 adjuncts in, 662–664 airway control devices Combitube, 663–664 endotracheal tube, 663 laryngeal mask airway, 663 laryngeal tube, 664 oropharyngeal and nasopharyngeal airways, 663 tracheostomy and cricothyroidotomy, 664 videolaryngoscopy, 664 oxygen, 662 ventilation devices automatic transport ventilators, 663 bag-mask-valve, 662 airway protection vs assisted ventilation in, 656–657, 656t cricoid pressure and Sellick maneuver in, 657 in different settings, 657–662 burns, 661 cardiopulmonary resuscitation, 658–659 cervical spine injury, 660 chest wounds, open penetrating, 660–661 drowning, 661–662 tension pneumothorax, 660–661 trauma, 659–660 traumatic brain injury, 661 emergency care skills in, 655–656 Resuscitation and anesthesia, history of, 17–37 differential pressure in, 28–31, 28f–30f of drowned, 18, 18f–20f in intensive care, 35 modern respirators in, 35 negative-pressure ventilators in, 20–21, 21f–26f for nonoperative patient barbiturate poisoning, 35 COPD and emphysema, 34–35 general, 31, 32f other disorders, 35 paralytic polio, 32–34, 32f–34f post thoracic surgery, 35 positive-pressure ventilation in in operating room, 22–23 in physiology laboratory, 22, 26f, 27f tracheal anesthesia in, 27–28, 27f, 28f tracheal intubation in, 25–27 translaryngeal intubation in, 31 ventilation adequacy in, 35–36 ventilators in quality control of, 36 weaning from, 36–37 vivisection in, 17–18 Resuscitation box, Braun, 20, 22f Resuscitation fluids, 1464–1466 albumin, 1465 blood and blood products, 1464–1465 crystalloids vs colloids, 1464, 1464t, 1465–1466 dextrans, 1465 gelatins, 1465 hydroxyethyl starch, 1465 rationale for, 1464 Resuscitator, automatic, 674–675, 675f Retinopathy of prematurity, from oxygen breathing, 1073–1074 Retroglottic airway, 884, 885f Retroperitoneum, fascial planes of, 1048f, 1049 Rhabdomyolysis, in severe asthma, 735t, 737 Rib cage–abdominal motion, 1313 Ridge, 16 Right main-stem bronchus intubation, with endotracheal tube, 898, 898f prevention of, 928 recognition of, 886, 898f, 923 Right-ventricular afterload on lung volume, 823, 824 positive end-expiratory pressure on, 268 Right ventricular failure (RVF), inhaled nitric oxide for, 1392t, 1393t Rigid bronchoscopy, negative-pressure ventilation for, 427 Rise time, 230 in pressure-controlled ventilation, 230 as target variable, 78–79, 80f Rocking bed, 435–441 applications of, 437–439 case study on, 440–441, 441f historical development of, 435 indications for, 439–440, 439t mechanism of action of, 436–437, 436f Rocuronium, 1193, 1194t for tracheal intubation, 890–891 Rotating beds, for ventilator-associated pneumonia prophylaxis, 1109–1110 Rowbotham, 31 Royal Human Society, resuscitation techniques and devices of, 18, 19f–20f Runaway phenomenon mechanisms of, 324 in proportional-assist ventilation, 324f, 334–335, 335f–337f S “Safe zone,” 496, 497f Salmeterol, 1420, 1420t Sarcoidosis, surfactant in, 1384 Sauerbruch, differential-pressure cabinet of, 28, 28f Scadding, Guy, 126, 126f Scheele, 6–7 on ventilation adequacy, 35 Schwake, negative-pressure ventilator of, 21 Scoliosis, thoracic See Neuromuscular disease Screening tests, purpose of, 1320 Seal, airway, 884–885 Sechrist SAVI system, 77 Secreted mucins, 1213 Secretions, airway, 1213–1231 aspiration of, subglottic, for ventilator-associated pneumonia prophylaxis, 1110 excess, intubation for, 121 fighting the ventilator from, 1243 future of Mucus Shaver in, 1229, 1231f Mucus Slurper in, 1229, 1230f lung protection from, independent lung ventilation for, 639–640 manual ventilation for exhaled ventilation techniques in, 1227 ventilatory circuits for manual hyperinflation in, 1227–1228, 1228f measurement of, 1362 mucus dysfunctions in, 1222 Index mucus retention disorders in, 1222–1223 physiology of, 1213–1218 airway lining fluid in, 1213 airway secretory cells in, 1214–1216, 1214f–1215f mucus and mucins in, 1213–1214, 1214f, 1214t mucus clearance via two-phase gas–liquid transport in, 1216–1217, 1217f, 1218f mucus production and secretion in, regulation of, 1216, 1216t periciliary liquid layer and mucociliary clearance in, 1215f, 1216 as postextubation distress predictor, 1362–1363, 1362f predictors of presence of, 1362, 1362f quantitative assessment of mucus production in, 1218 mucus removal in, 1219–1222, 1219f, 1220t–1221t retained, from translaryngeal intubation, 908 retention of, from translaryngeal intubation, 908 suctioning for, 1110, 1223–1227 (See also Suctioning, airway) unknowns in, important, 1229 Secretory cells, airway, 1214–1216, 1214f–1215f Sedation adequacy of, assessing, 1187 agent selection in, 1187–1191 (See also specific agents) barbiturates, 1191 benzodiazepines, 1187–1188, 1188t butyrophenones (haloperidol), 1189–1190, 1190t dexmedetomidine, 1190, 1190t fospropofol, 1189, 1190t inhalational anesthetics, 1191 ketamine, 1190–1191 propofol, 1189, 1190t for asthma, severe, 733–734 in critically ill mechanically ventilated, delivery of, 1191–1192, 1192f future of, 1195 indications for, 1186–1187 rationale for, 1183 for respiratory discomfort in ventilation, 1276 on respiratory reflexes, 354 unknowns in, important, 1195 for weaning, 1346–1347 Sedative-hypnotics, for tracheal intubation See also specific agents benzodiazepines, 890 etomidate, 889 ketamine, 890 propofol, 889 short-acting barbiturates, 889 Sedatives See also specific agents on neurocognition in critical illness, 1511 with proportional-assist ventilation, 341 Selective airway protection, independent lung ventilation for, 635t, 637–640 for bronchial repair protection, 640 for lung protection from secretions, 639–640 for massive hemoptysis, 638–639, 639t for whole-lung lavage, 637–638, 637f Selective phosphodiesterase E4 inhibitors, 1424 Self-inflating bag circuits, 1228 Sellick maneuver, 657, 879, 879f Semirecumbent position, for ventilator-associated pneumonia prophylaxis, 1109 Sensitivity, 1320 × tables and, 1320–1322, 1321f variations in, 1322 ventilator, 48 Sensors, of patient effort, 411 Sepsis definition of, 1155 on neurocognition in critical illness, 1511 permissive hypercapnia for with pulmonary sepsis, 386–387, 386f, 387f with systemic sepsis, 387–388, 388f in sinusitis, 1124f, 1125–1126 Sequential diagnostic testing, in weaning outcome, 1324–1326, 1326f Servetus, Servo targeting, 53, 53f Set-point targeting, 52, 52f Settings, ventilator, 139–155 See also specific disorders and ventilators abbreviations for, 142t for acute lung injury and hypoxic respiratory failure, 145–151 end-expiratory lung volume manipulation in, 145–147, 145f–147f fractional inspired oxygen concentration in, 145 minute ventilation in, 151 pathophysiology in, 145 respiratory rate in, 149–150 tidal volume in, choosing appropriate, 147–149, 148f timing variables in I:E ratio, 150 inspiratory flow, 141f, 150 mean expiratory flow, 150–151 capabilities in, 139–143 dual-control and advanced closed-loop modes in, 142–143 inspired-gas composition choice in, 140 machine sensing of patient demand in, 140 mechanical output in, options for, 140 microprocessors in, 139 pressure-preset mode in, 141–142 synchronized intermittent mandatory ventilation in, 142 volume-preset mode in, 141, 141f for common potentially adverse patient– ventilator interactions patient effort–machine-delivered breath asynchrony in, 154–155, 155f respiratory alkalosis in, 154 mechanical determinants of patient– ventilator interactions in expiratory mechanics in, 144 inspiratory mechanics in, 143–144, 143f linear single-compartment model limitations in, 144 for obstructive lung diseases, 151–154 continuous positive airway pressure in, 152–153, 153f dynamic hyperinflation minimization in, 151–152, 152f pathophysiology in, 151 ventilatory pump failure and chronic CO2 retention in, 153–154 therapeutic endpoints in, 144–145 1553 Severe Respiratory Insufficiency Questionnaire, 693, 693f, 693t Severy, negative-pressure ventilator of, 21, 25f Sevoflurane, for severe asthma, 734–735 Shallow respiration, 106 Shape-signal, 77 Shearing forces, 707 Shock, 118–120 cardiogenic, inhaled nitric oxide for, 1392t clinical presentation of, 119–120, 119f definition of, 118 mechanical ventilation for, 125 physiologic effects of, 118–119 Sickle cell disease, inhaled nitric oxide for, 1392t Sickness, 1260 Sickness behavior, 1263 Siebe, 11, 12f Siebe, Gorman, and Company, 11, 13f Siggaard-Anderson, 10 Sighs, 708 Signal alignment, in systematic error, 1143, 1144f Signals definition of, 1146 monitor, 1146 Silicone nasal interface, in NIPPV for neuromuscular disease, 766–767, 768f Single-compartment models, linear, 144 Single-fiber action potential definition of, 354 mechanisms of, 355, 355f Single lung transplantation (SLT) independent lung ventilation for airflow obstruction in, 642–646 with acute native lung hyperinflation, 643–645, 643f complications of, 645t double-lumen tracheostomy tube in, 646, 646f double-lumen tube choice in, 645, 645t double-lumen tube complications in, 645t, 647–648 outcome of, 646 pathophysiology of, 642–643, 642t technique and goals of, 645–646 ventilator settings in, 645, 645t pathophysiology of, 642–643, 642t Sinus arrhythmia, respiratory, 843 Sinus effusions, from translaryngeal intubation, 900, 914 Sinuses, maxillary CT scans of, 1126–1127, 1127f–1130f ultrasound of, 1127–1128, 1131f Sinuses, paranasal, 1123 Sinus infections (sinusitis), 1123–1133 diagnosis of, 1126–1130 clinical, 1126 microbiologic for infectious maxillary sinusitis, 1128–1129 for ventilator-associated maxillary sinusitis, 1130, 1131f radiographic, 1126–1138 CT scan, 1126–1127, 1127f–1130f ultrasound of maxillary sinuses, 1127–1128, 1131f epidemiology and complications of incidence in, 1126 nosocomial sinusitis and ventilatorassociated pneumonia, 1126 1554 Index Sinus infections (sinusitis) (Cont’d.) future of, 1133 paranasal sinus physiology in classical hypotheses of, 1123 recent hypothesis on, nitric oxide, 1124, 1124f pathogenesis and predisposing factors in experimental models of, 1124–1125 foreign bodies in, nostril, 1125 macroscopic and microscopic aspects of, with ventilation, 1125 meatus inferior size and body position in, 1125 sepsis in, 1124f, 1125–1126 prevention of ventilator-associated sinusitis in, 1130–1132 from translaryngeal intubation, 900, 914 management of, 925 recognition of, 923–924 treatment of infectious maxillary sinusitis in antibiotic penetration into antral mucosa in, 1132 sinus drainage and antibiotic therapy in, 1132–1133 unknowns in, important antibiotics for ventilator-associated maxillary sinusitis in, 1133 frontal, ethmoid, and sphenoid sinus relevance in, 1133 ventilator-associated, 1097 Skeletal muscle, structure of, 355, 355f Sleep, in ventilator-supported, 1293–1303 assist-control ventilation on, 162–163 disruption of (See Sleep disruption (fragmentation)) future of, 1303 in ICU, 1294–1300 patient perception of, 1294 polysomnography of, 1294, 1295f–1297f improvement of ICU environment optimization in, 1302 medications in, 1302 mode of ventilation in, 1302–1303, 1303f treatment of underlying illness in, 1302 in noninvasive positive-pressure ventilation, monitoring of, 481 in pressure-support ventilation, 207–208 sleep stages and, 1293, 1294f unknowns in, important, 1303 Sleep, normal, 1293, 1294f Sleep apnea, sleep disruption from, in ICU, 1295 Sleep architecture, 1293 Sleep deprivation, in ICU, 778 Sleep disruption (fragmentation), 1299–1300, 1300f in acute respiratory distress syndrome survivors, 1301 causes of, 1295–1300 circadian rhythm in, 1297–1298 ICU environment in, 1298–1299, 1299f, 1300t mechanical ventilation in, 1299–1300, 1300f medical disorders in, 1295 medications in, 1295–1297, 1298t consequences of chronic insomnia, 1301 host defenses, 1301 ICU psychosis, 1301 REM rebound, 1301 weaning delay, 1301 definition of, 1293 in ICU, 1294–1301 (See also Sleep, in ventilator-supported) causes of, 1295–1300 consequences of, 1300–1301 patient perception of, 1294 polysomnography on, 1294–1295, 1295f–1297f ventilator and settings on, 1254–1255 Sleep–wake transition, fighting the ventilator from, 1242f, 1254–1256, 1255f Small airway collapse, from anesthesia and surgery, 599 SmartCare/PS ventilator, 55, 55f Smart Pulmonary View, 92, 94f Sniff esophageal pressure (Pes-sniff ), 763, 764f Sniff nasal inspiratory force, in neuromuscular disease, 763–764, 765f SnNout, 1320 Snoring, 121 Sodium 2-mercaptoethane sulphonate (MESNA), 1228–1229 Sodium balance, 1460 Sodium bicarbonate, for hypercapnic acidosis, 393 Soluble triggering receptor expression on myeloid cells-1 (sTREM-1), 1103 Sore throat, postextubation, 910 Spallanzani, Speaking tubes, pneumatic, 954, 959 Specificity, 1320 × tables and, 1320–1322, 1321f definition of, 1328 variations in, 1322 Spectrum, 1326 Spectrum bias, 1326–1327 Speech breathing in, 1282 with diaphragmatic pacing, 1406 mechanisms of, 366 with tracheostomy, one-way valve for, 1285 Speech, after tracheotomy, 954–959 electrolarynx for, 958t, 959 fenestrated tracheotomy tube for, 959 phonation valves for, 958t, 959, 959f pneumatic speaking tubes for, 954, 959 techniques and methods for, 954, 956t–958t Speech, ventilator-supported, 1281–1289 alternatives to, 1289, 1289f breathing in, 1282 candidates for interventions for, 1288 cautions with, important, 1288–1289 fundamentals of, 1282 future of, 1289 health care professional role in, 1289 importance of, 1281–1282 with invasive positive-pressure ventilation, 1282–1287 behavior interventions for, 1287 clinical scenario of, 1283, 1287 tracheostomy tube cuff deflation in, 1282–1283, 1284f ventilator adjustments for, 1283–1287 with volume-controlled ventilation, 1283, 1284f with noninvasive positive-pressure ventilation, 1288 overview of, 1287t with phrenic nerve pacer ventilation, 1287t, 1288 unknowns in, 1289 Speech, with invasive positive-pressure ventilation, ventilator adjustments for, 1283–1287 inspiratory time, PEEP, and tidal volume in, 1285, 1286f one-way valve replacement with PEEP in, 1285, 1287f pressure-controlled ventilation and PEEP in, 1285, 1286f principles and purpose of, 1283–1285 risks and benefits of, 1285–1287 Spinal cord injury See also Neuromuscular disease cervical, from translaryngeal intubation, 899 Spine injury, cervical, ventilation during resuscitation in, 660 Spirophore, 21, 22f Spleen permissive hypercapnia for, 390–391 positive end-expiratory pressure on circulation and oxygenation in, 270–271 Spofford-Christopher Oxygen Optimizing Program, 556 Spontaneous breathing See Breathing, spontaneous Spontaneous breathing trials, for weaning, 1340 Spontaneous ventilation continuous, 51 as exercise, 833 in independent lung ventilation, 635 SpPin, 1320 Stadie, 35 Starch, hydroxyethyl, 1465 Starling equation, 1461, 1462f Static hyperinflation, 619 Status asthmaticus See Asthma, severe (status asthmaticus) Stebbing, 35 Sternomastoids, in respiratory distress, 105, 105f Steroid myopathy, from ventilator assistance in COPD, 752 Stomach inflation, in rescue ventilation, 657 Stomal scars, after tracheotomy, 951 Stoma maintenance device, 960, 960f Stoma stent, 960, 960f Stoma wound infection, after tracheotomy, 948 Stow, 10 Strain, mechanical (tissue) etiology of, 706 lung deformation as, 148–149 positive end-expiratory pressure on, 709–710, 709f on tidal volume and functional residual capacity, 706–707, 707f, 708f Strength training, respiratory muscle, for weaning, 1345–1346 Stress, mechanical (tissue) etiology of, 706 positive end-expiratory pressure on, 709–710, 709f on tidal volume, 706–707, 707f, 708f in ventilator-induced lung injury, 704–706, 705f, 706f Index Stress amplification, in acute respiratory distress syndrome, 702–703, 703f Stress cardiomyopathy, in severe asthma, 735t, 736–737, 736f Stress-related mucosal disease, 974–976, 975f epidemiology of, 974–975 pathophysiology of, 975–976, 975f treatment of, 976 Stress-ulcer prophylaxis, for ventilatorassociated pneumonia, 1095–1096, 1111 Stridor, 121 postextubation, 911 avoiding, 930–931 management of, 925 in neonates and children, 589–590, 590f from upper airway obstruction, 1356 Structure disorders, 127 Structured prevention policy, for ventilatorassociated pneumonia prophylaxis, 1111–1112 Sturmius, 11 Subcutaneous emphysema after tracheotomy, 948 clinical manifestations of, 1051–1052, 1051f, 1052f management of, 1055–1056 Subglottic secretion aspiration, for ventilator-associated pneumonia prophylaxis, 1110 Submarines, early history of, 14 Submucosal gland, 1214–1216, 1215f Succinylcholine properties and use of, 1193, 1194t for tracheal intubation, 890 Sucralfate, for ventilator-associated pneumonia, 1095–1096, 1111 Suctioning, airway, 1223–1227 catheter characteristics in, 1225, 1226f complications of, 1226–1227, 1362 endotracheal procedure in, 1223, 1224f future of Mucus Shaver in, 1229, 1231f Mucus Slurper in, 1229, 1230f gloves in, sterile, 1225–1226 indications for, 1223, 1224f, 1225f pharmacologic agents in mucoactive, 1228–1229 role of, 1228 skilled techniques for, 928t, 929–930 sterile gloves in, 1225–1226 suction method in, open vs closed, 1223–1225 swivel connector in, 1226 unknowns in, important, 1229 vacuum adjustable regulator in, 1225 water in, sterile, 1226 Suction systems, closed, neonatal and pediatric, 578 Superoxide dismutase (SOD), 1078f, 1079 for oxygen toxicity, 1081 in ventilator-induced diaphragm dysfunction, 1032 Supine positioning on gas exchange distribution of perfusion in in acute respiratory failure, 1173–1174 in normal lungs, 1173 distribution of ventilation in in acute respiratory failure, 1171f, 1172 in normal lungs, 1172 regional lung inflation in in acute respiratory failure, 1171, 1171f in normal lungs, 1170, 1170f ventilation–perfusion matching in, 1174 on ostial patency, 1125 on ventilator-associated pneumonia risk, 1096 SUPPORT study, 1475, 1477, 1478 Supraglottic airway, 884–885, 884f Surfactant, 1375–1384 in acute respiratory distress syndrome, 701 anesthesia and surgery on, 600 composition of, 1375–1376 endogenous, 1083 function of, 1375 inhaled nitric oxide therapy on, 1399–1400 metabolism of extracellular, 1376–1377, 1377f intracellular, 1376, 1376f in neonatal respiratory distress syndrome, 1375 physiology of in injured lung in acute lung injury and ARDS, 1378 mechanisms of alterations in, 1378–1380, 1379f in normal lung biophysical function in, 1377 host-defense function in, 1377–1378 Surfactant-associated proteins, 1375–1376 Surfactant therapy factors in response to, 1382, 1383f future research on combination therapies in, 1383 role in other diseases in, 1383–1384 in injured lung efficacy of delivery and dosing in, 1381–1382 mechanical ventilation on, 1382 nature of injury in, 1382–1383, 1383f preparation in, 1381, 1381t phase II and II clinical trials on, 1380–1381, 1380t ischemia–reperfusion injury from lung transplantation, 1384 for lung protection, 1012 for oxygen toxicity, 1083 for pneumonia, 1383–1384 for respiratory distress syndrome, neonatal, 579 Surgery See also specific procedures heart–lung interactions in, ventilation on, 835f, 841–842 mechanical ventilation in (See Anesthesia and surgery, with ventilation) respiratory effects of, 597–604 on ventilator-associated pneumonia risk, 1094–1095 Survivors of catastrophic illness, 789 See also Chronic ventilator facilities (CVFs) Swallowing after ICU discharge, 778, 778f after tracheotomy, 954, 955f, 955t in noninvasive neurally adjusted ventilatory assistance, 365 Swivel connector, for airway suctioning, 1226 1555 Synapse Biomedical system, 1409, 1409f, 1410f Synchronized airway pressure release ventilation, 310 See also Airway pressure release ventilation (APRV) Synchronized independent lung ventilation (SILV), 632–634 Synchronized intermittent, 51 Synchronized intermittent mandatory ventilation (SIMV), 142 See also Intermittent mandatory ventilation (IMV) in anesthesia, 602t in neonates and infants, 585, 585f vs pressure-support ventilation, 215 for weaning, vs intermittent mandatory ventilation, 191–192, 191t Syndrome, 127 Systematic error definition of, 1140, 1140f, 1141f sources of, 1143–1144, 1143f, 1144f calibration vs data collection conditions in, 1143–1144 frequency response, 1143, 1143f range errors, 1143, 1143f response time, 1143 signal alignment, 1143, 1144f zero offset error, 1143 Systemic air embolism clinical manifestations of, 1052–1053 management of, 1056 Systemic inflammatory response syndrome, on neurocognition in critical illness, 1511 Systemic pressure, mean, 826, 826f Systemic sepsis, permissive hypercapnia for, 387–388, 388f Systemic venous return, in heart–lung interactions in mechanical ventilation, 826–829, 826f–828f System One error, 1308 T Tachycardia, from ventilator-supported patient transport, 670 Tachycardic-hypertensive response, to translaryngeal intubation, prevention of, 927 Tachypnea, 106 Tacit knowledge, 1159–1160 Talking tracheostomy tube, 1289, 1289f Talking tubes, 954, 959 Tank respirator early, 20, 21f Emerson’s early, 21, 26f Tank ventilators, negative-pressure, 417–418, 419f Target, 52 Targeting schemes, 51–56, 57 adaptive, 54, 54f automatic, 52 classification of, 50t closed-loop control, 51–52, 51f definition of, 51 dual, 52–53 future of, 93–95, 95f intelligent, 55–56, 55f, 56f on operator inputs/outputs, 57, 60t optimal, 54, 54f servo, 53, 53f set-point, 52, 52f 1556 Index Target variables, 48, 49f, 77–85 automatic tube compensation, 85, 86f definition and role of, 77 inspiratory flow, 70f, 82–83, 84f minute ventilation, 81–82, 82t neurally adjusted ventilatory support level, 83–85, 86f percent support, 83, 85f pressure, 77–79, 78f–80f tidal volume, 79–81 Tension pneumothorax, ventilation during resuscitation in, 660–661 Tension–time index definition and use of, 1314 for respiratory muscles in weaning failure, 1314–1315, 1315f Terminology, disease diagnostic process, treatment, and value judgment in, 127–128 disease characteristics in, 128 disease definition in, 127 essentialist and nominalist definitions in, 127–128 factual implications of, 128 nosology in, 126 Tertiary ammonium-containing muscarinic antagonists, 1421 Test-referral bias, 1327–1328, 1327f Tetraplegia, ventilator-dependent, diaphragmatic pacing for, 1410–1411, 1411f Theophylline for bronchodilation, 1423 fighting the ventilator from, 1248 Therapeutic endpoints, ventilator settings and, 144–145 Therapeutic hypercapnia, 378, 396 Therapy, conflation of, 1160 Thick-filament myopathy, 1507 Thinking, two independent systems of, 1308 Thiopental poisoning with early ventilation and resuscitation for, 35 translaryngeal intubation for, discovery of, 35 for sedation, 1191 Thoracic lymph drainage, positive endexpiratory pressure on, 272 Thoracic pressure See Intrathoracic pressure Thoracic scoliosis See Neuromuscular disease Thoracic surgery, independent lung ventilation in, 635t, 636–637 Threshold oxygen tension, for oxygen toxicity, 1069–1070, 1069f, 1070f Threshold value, 1329–1330 Thrombocytopenia, 981, 981t Thromboembolism, inhaled nitric oxide for, 1392t Thyromental distance, 876, 877f Tidal volume (VT) for acute lung injury and hypoxic respiratory failure, 147–149, 148f for acute respiratory distress syndrome, optima, 715–716 in anesthesia and surgery, 608, 611 in asthma, severe, 729f, 730f, 731–732, 731f on barotrauma, 1045, 1045t breath-to-breath variation in, 1147–1148, 1148f in chronic obstructive pulmonary disorder, 744 in high-frequency oscillatory ventilation, 502–503, 502t permissive hypercapnia on, 393 in pressure-controlled ventilation, 231–232 for speech with invasive positive-pressure ventilation, inspiratory time and PEEP with, 1285, 1286f as target variable, 79–81 tissue stress on, 706–707, 707f in ventilator-induced lung injury, vs plateau pressure, 708, 709f Tightness, in bronchoconstriction, 1273 Time for acute lung injury and hypoxic respiratory failure I:E ratio, 150 inspiratory flow, 141f, 150 mean expiratory flow, 150–151 as trigger variable, 75 Time-cycled, pressure-limited (TCPL) ventilation, in neonates and infants, 583, 584f Time-cycled mode, 228 Time-cycled ventilation, 1253 Time-triggered ventilation, vs assisted ventilation, 239 Tiotropium, 1421 T-low, 89–90, 90f Tonic Edi, 359 Tooth aspiration, from endotracheal tube placement, 897, 897f Tossach, 18 Total body water, 1459 Trachea infection, from translaryngeal intubation, 907 Tracheal abrasion, minimizing, 930 Tracheal anesthesia, history of, 27–28, 27f, 28f Tracheal cannulation techniques, surgical, 945–947 cricothyroidotomy, 946–947 minitracheotomy, 947 open surgical tracheotomy, 945 Tracheal cartilage destruction, from translaryngeal intubation, 906 Tracheal cuff-site injury, 915f, 919–921, 919f, 920f Tracheal dilation, 906, 913 Tracheal edema and inflammation, 905 Tracheal epithelium, translaryngeal intubation on, 907 Tracheal gas insufflation, with permissive hypercapnia, 394 Tracheal granuloma, 905, 913 management of, 926 postextubation, 911 Tracheal injury from endotracheal tube, 898 from translaryngeal intubation pathogenesis of, 915, 915f, 916f recognition of, 924 Tracheal intubation, 874–881 See also specific types airway evaluation in, 876–878 head and neck mobility and extension in, 877 history in, 876 Mallampati classification in, 876, 876f mandible size in, 876, 877f other factors in, 877–878 upper-lip bite test in, 877, 877f equipment and setup in, 878, 878t history of, 25–27 indications for, 874–876 physiologic responses in, 888–889 techniques in, standard, 878–881 direct laryngoscopy in, 880–881, 880f oral vs nasal intubation in, 878 rapid sequence induction of anesthesia in, 879–880, 879f, 879t Tracheal necrosis, from translaryngeal intubation, 906 Tracheal pseudomembranes, postextubation, 911–912 Tracheal ring fracture and herniation, after tracheotomy, 951 Tracheal rupture and laceration, from translaryngeal intubation, 906 Tracheal stenosis, 913, 914f after tracheotomy, 949–950 from translaryngeal intubation diagnosis of, 924–925 management of, 926 recognition of, 924–925 Tracheal submucosal hemorrhage, from translaryngeal intubation, 905, 905t Tracheal tug, 106, 107f Tracheal ulceration, from translaryngeal intubation, 902f, 905, 905t Tracheitis, pseudomembranous, from translaryngeal intubation, 907 Tracheoarterial fistula after tracheotomy, 950–951, 951f from translaryngeal intubation, 907 Tracheobronchitis from oxygen breathing, 1069 from translaryngeal intubation, 907, 921 Tracheobronchomalacia, pediatric, 574, 575f Tracheocutaneous fistula, after tracheotomy, 951 Tracheoesophageal fistula after tracheotomy, 950, 950f fighting the ventilator from, 1242 during tracheotomy, 947–948 from translaryngeal intubation, 906–907, 909 Tracheomalacia after tracheotomy, 950 from translaryngeal intubation, 906 Tracheostomy aspiration in, 778 early history of, 25 for mechanical ventilation in resuscitation, 664 mouth with, 103, 104f for neuromuscular disease, 766, 767f one-way valve with, for speech, 1285 Tracheostomy tube cuffed, Trendelenburg, 27, 27f double-lumen, 646, 646f Tracheotomy, 941–961 comfort implications of, 1277 complications of, 947–951 early postoperative hemorrhage, 948 inadvertent decannulation, 948 pneumonia, 948–949 stoma wound infection, 948 subcutaneous emphysema, 948 tube obstruction, 949 Index intraoperative cardiorespiratory arrest, 947 hemorrhage, 947 pneumothorax and pneumomediastinum, 947 recurrent laryngeal nerve injury, 947 tracheoesophageal fistula, 947–948 late poor airway alignment, 949 tracheal and laryngotracheal stenosis, 949–950 tracheal ring fracture and herniation, 951 tracheoarterial fistula, 950–951, 951f tracheocutaneous fistula and stomal scars, 951 tracheoesophageal fistula, 950, 950f tracheomalacia, 950 decannulation of, mortality from, 779 history of, 941 indications for, 941 in neonates and children, 578 prognosis and quality improvement in, 960–961 vs prolonged translaryngeal intubation, 951–952, 951t, 952t special considerations in nutrition, 954 swallowing, 954, 955f, 955t tube cuff pressure management, 953–954 voice, speech, and language, 954–959, 956t–958t, 959f electrolarynx in, 958t, 959 fenestrated tracheotomy tube in, 959 phonation valves in, 958t, 959, 959f pneumatic speaking tubes for, 954, 959 techniques and methods for, 954, 956t–958t weaning and decannulation in, 959–960, 960f surgical techniques for airway access in, 942–945 cricothyroidotomy, 944 minitracheotomy, 945 percutaneous tracheotomy, 942–944, 942f standard surgical tracheotomy, 942, 942f surgical techniques for tracheal cannulation in, 945–947 cricothyroidotomy, 946–947 minitracheotomy, 947 open surgical tracheotomy, 945 percutaneous dilational tracheotomy, 945–946 timing of, during ventilation, 951–953 in ventilator-associated pneumonia, 1096 Tracheotomy phonation valves, 958t, 959, 959f Tracheotomy tube, fenestrated, 959, 959f Train-of-four stimulation, monitoring in, 1154, 1154f Transalveolar pressure, upper limit for, 235 Transcellular fluid volume, 1459 Transdiaphragmatic pressure (Pdi) phrenic nerve function assessment via, 1412 twitch in chronic obstructive pulmonary disease, 743, 744f in neuromuscular disease, 763, 764f, 765f Transfer See also Transport, ventilatorsupported patient to home mechanical ventilation, 688, 689t from ICU to community with neuromuscular disease, 773 from ICU to lower-intensity sites of care, 1498 Transient neuromuscular blockade, 983t Translaryngeal intubation (TLI) in emergency ventilation, 655–656 history of, 31, 895 prolonged, 952, 952t terminology for, 895 vs tracheotomy, 951–952, 951t, 952t Translaryngeal intubation (TLI) complications, 895–931 cardiac arrest and mortality rate in, 899–900 classification of, 896t with endotracheal tube in place, 900–909 bronchial, 907 esophageal, 909 gastric, 909 laryngeal, 901–905 glottic, 903–904, 904f schematic and lesions of, 901, 902f subglottic, 905 supraglottic, 902t, 903 malnutrition, 909 mechanical, 908–909, 908t musculoskeletal, 909 nasal, 900, 900f neurologic, 909 oral, 900–901, 901f pain and discomfort, 908 paranasal, 900 pharyngeal, 901 physiologic, 909 pulmonary, 907–908 tracheal, 902f, 905–907, 905t unplanned extubation, 908 in endotracheal tube placement, 896–900 bacteremia, 898 bronchial, 898, 898f cardiovascular, 899 esophageal, 899 gastric, 899 laryngeal, 897–898 musculoskeletal, 899 nasal and paranasal, 896–897 neurologic, 899 oral, 897, 897f pain, from inadequate premedication, 898 pharyngeal, 897, 897f pulmonary, 898 tracheal, 898 extubation during, 909–910, 910t after, 910–913 early, 910–912, 910t, 911t late, 911t, 912–913, 912t frequency of, 896, 896t future of, 931 history of, 895 management of, 925–926 pathogenesis of, 913–921, 921t with endotracheal tube in place, 914–921 anatomic and physiologic influences in, 914–916, 915f, 916f 1557 endotracheal tube influences in, 916–917 granuloma formation, 918–919 laryngeal injury, 917–918 pulmonary complications, 921 tracheal cuff-site injury, 915f, 919–921, 919f, 920f during endotracheal tube placement, 913–914 in extubation, during and after, 921 prevention of, 926–931 with endotracheal tube in place, 928–930, 928t, 929f during endotracheal tube placement, 926–928, 926t extubation, during and after, 930–931 overview of, 926 from prolonged intubation, 952, 952t recognition of esophageal intubation, 886, 923 laryngeal injury, 924 nasal and oral injury, 924 right main-stem bronchus intubation, 886, 898f, 923 sinusitis and otitis, 923–924 tracheal injury, 924 tracheal stenosis, 924–925 studies of, prospective, 921–923, 922t unknowns in, important, 931 Transpiratory pressure, 46 Transport, ventilator-supported patient, 669–680 aeromedical, 673 ancillary equipment in humidification, 679 oxygen supply, 679 contraindications to, 673 equipment and monitoring during, 673–674, 673t equipment malfunction or mishaps in, 674 interhospital, 670 intrahospital, 669–670 on ventilator-associated pneumonia risk, 1097 manual ventilation in, 674 physiologic effects and complications of cardiovascular, 670–671 hypothermia, 671 intracranial pressure increase, 671 overview of, 670, 671t respiratory, 671 portable ventilator for, 674 preparation and planning for, 670 risks and benefits of, 670 studies on, 672t transport ventilators for, 674–679 attributes of, 677–678 automatic resuscitator, 674–675, 675f definition of, 674 performance issues in, 678–679, 679f simple, 675, 675f, 676f sophisticated, 675–677, 676f, 677f Transpulmonary pressure, 844 in airway pressure release ventilation, 307 in ventilator-induced lung injury, 708 Transpulmonary thermodilution, 1467 Transthoracic electrical impedance, as trigger variable, 77 1558 Index Transtracheal gas insufflation (TGI) for acute lung injury and ARDS, 557–559, 558f–561f bedside adjustments in, 562–563, 564f for chronic respiratory failure, 557, 558f emergency transtracheal ventilation in, 557 endotracheal tube in, 562 future of, 565 for liberation from ventilation, 559–561 mechanism of action of, 553–554 modes of operation of, 554, 554f, 555f monitoring of, 563–565, 565f operational characteristics of catheter flow rate in, 561, 562f catheter position in, 561 catheter shape in, 561–562 endotracheal tube design in, 562 humidification in, 562 physiologic effects of, 554–556 transtracheal oxygen therapy in, 556–557, 556f unknowns in, 565 Transtracheal oxygen therapy (TTO) complications of, 556–557 mechanisms of, 556, 556f technique in, 556 ventilation in, 556 Transtracheal ventilation, emergency, 557 Trauma See also specific types noninvasive positive-pressure ventilation for, 459 ventilation during resuscitation in, 659–660 Traumatic brain injury (TBI), ventilation during resuscitation in, 661 Treatment See also specific disorders and types value judgments and, 128 Trendelenburg position on anesthesia, 27 cuffed tracheostomy tube of, 27, 27f Trends, on displays, 91, 92f Treweek, 31 Triamcinolone, as bronchodilator, 1421 Trigger, 11–13, 57 Trigger delay inspiratory, in pressure-support ventilation, 209 in mechanical ventilation, 816, 816f in ventilator-treated chronic obstructive pulmonary disorder, 749, 750f Trigger failure, monitoring for, 1152, 1153f Triggering, 140 definition of, 57 fighting the ventilator from, 1250, 1250f flow, 48 ineffective fighting the ventilator from, 1246f, 1250–1251 in mechanical ventilation, 816–817, 816f in pressure-support ventilation, 209–211, 209f in ventilator-treated COPD, 749, 750f, 751f in neurally adjusted ventilatory assist, 353f, 362, 363f ventilator, 140 Trigger variables, 47–48 in assist-control ventilation, 159 in operator interface, 74–77 definition and role of, 74–75, 75f diaphragmatic signal, 77 flow, 76 other signals, 77 pressure, 75–76, 76t time, 75 volume, 76–77 Trimethoprim-sulfamethoxazole, for chronic obstructive pulmonary disease, 754 Trolox, for ventilator-induced diaphragm dysfunction prevention, 1036–1037, 1037f Tromethamine, for hypercapnic acidosis, 394, 394f Trousseau, 25 T-tube trial, 1308–1309 for postextubation distress, 1358–1359 for weaning, 1339–1340, 1339f Tube compensation, automatic, 85, 86f Tube cuff pressure management, after tracheotomy, 953–954 Tube obstruction, after tracheotomy, 949 Tuberculosis, home mechanical ventilation for sequelae of, 692 Tuffier, 27 Tunnicliffe, 35 Turbinates, nasal, 871, 872f Turbine design, of anesthesia ventilators, 608 Twitch potentiation, 1314 Twitch transdiaphragmatic pressure (Pdi) in chronic obstructive pulmonary disease, 743, 744f in neuromuscular disease, 763, 764f, 765f × tables, 1320, 1321f Two-handed jaw-thrust mask-hold technique, 874, 876f Two-phase gas–liquid transport, in mucus clearance, 1216–1217, 1217f–1219f Two-point calibration, 1142, 1142f U Ubiquitin–proteasome pathway, 1030, 1031f Ultrasonic nebulizers, 1425 configuration of, 1427–1428 for inhaled antibiotics, 1449 Ultrasound, for monitoring fluid therapy, 1467 Unassisted breath, 51 Underhumidification, on upper airway, 1201 Unilateral airflow obstruction See also specific types independent lung ventilation for, 642–647, 642t patient selection for, 646–647 in single lung transplantation, 642–646 for acute native lung hyperinflation, 643–645, 643f complications of, 645t double-lumen tracheostomy tube in, 646, 646f double-lumen tube choice in, 645, 645t outcome of, 646 pathophysiology of, 642–643, 642t technique and goals of, 645–646 ventilator settings in, 645, 645t with unilateral bronchospasm, 646 pathophysiology of, 642 Unilateral atelectasis, independent lung ventilation for, 642 Unilateral bronchospasm, independent lung ventilation for, 646 Unilateral parenchymal injury, independent lung ventilation for, 641 Uni-Vent 706, 675, 676f Uni-Vent 731, 677, 677f Uni-Vent 754, 677 Univent tube, for lung separation in independent lung ventilation, 631–632, 633f Unplanned extubation, 1367–1368, 1369f endotracheal tube position in, 1368, 1369f risk factors in, 1368 Unrecognized difficult airway, 883–884 Upper airway anatomy and physiology of, 1199–1200 feedback from, on respiratory reflexes, 353–354, 354f negative-pressure ventilation on, 422–423 Upper airway obstruction, 120–121, 120f See also specific types heart–lung interactions in, ventilation on, 826f, 836–837 intubation vs ventilation for, 120–121, 120f noninvasive positive-pressure ventilation for, 454 postextubation, 1355–1356, 1355f sequelae of, 1356 Upper-esophageal sphincter, in noninvasive neurally adjusted ventilatory assistance, 365–366 Upper inflection endpoint (UIP), 259, 264 Upper-lip bite test, 877, 877f Upper respiratory tract See Upper airway Utility, 1491 V Vacuum adjustable regulator, 1225 Vacuum pump, 5, 6f Vagus nerve, 843 Vallecula, 871, 873f Valsalva maneuver, 120–121 Value judgments, in treatment decisions, 128 Valve Bennett, positive-pressure, 33, 33f demand, in pressure-support ventilation, 207 flow-control, 68, 68f, 69f one-way PEEP replacement of, for speech with invasive positive-pressure ventilation, 1285, 1287f with tracheostomy, 1285 phonation, after tracheotomy, 958t, 959, 959f Vapor, 1200 Vaporization, 1200 Vapor pressure, 1200 Variable costs, 1490 Variable flow systems, continuous positive airway pressure, in neonates, 583 Variable pressure support, 143 Variables See also specific variables baseline, 49 control, 46–47, 50, 50t algorithm for, 50, 50t, 57, 58f definition of, 46 phase, 47, 48f Index Vascular pressure, in ventilator-induced lung injury, 707–708 Vasoconstriction hypoxic pulmonary, 823 from normobaric hyperoxia, 1074, 1074t Vasodilation after inhaled nitric oxide therapy, 1399 cerebral, from hypercapnic acidosis, 380 from nitric oxide, 1391, 1391f pulmonary from normobaric hyperoxia, 1066–1068, 1066f from oxygen breathing, 1066–1068, 1066f Vasodilators See also specific agents fighting the ventilator from, 1248 Vasopressin, 1459–1460, 1460t Vasopressor titration, monitoring for, 1153–1154 Vecuronium, 1193, 1194t Venoarterial cannulation, in extracorporeal life support, 521–526 central cannulation in, 523 circuit design and components in, 521–522, 521f–523f femoral cannulation in, 523–526, 524f–526f hybrid, 525–526, 526f hybrid venoarterial, 525–526, 526f venoarterial, 523–525, 523f–525f Venous return airway pressure release ventilation on, 308 in heart–lung interactions in ventilation, 826–829, 826f–828f positive end-expiratory pressure on, 267–268 Venous thromboembolism (VTE), 985–987 diagnosis of, 985–986, 986f incidence and risk factors for, 985 prevention of, 987 risk stratification in, 986–987 Venovenous circuit, in extracorporeal life support, 529, 534f Venovenous double-lumen cannulation, in extracorporeal life support, 529, 533f Venovenous extracorporeal CO2 removal, 548–550 for acute respiratory distress syndrome, 549–550, 550t anticoagulation in, 548 bypass technique in, 548, 549f clinical management in, 548 complications of, 548–549 Ventilation See also specific types adequacy of, history of, 35–36 economics of, 1489–1498 (See also Economics, of ventilation) permissive hypercapnia on, 380 in spontaneous breathing vs controlled mechanical ventilation, 306, 306f withholding and withdrawing, ethics of, 1473–1482 (See also Ethics, of withholding and withdrawing ventilation) Ventilation, distribution of See Distribution of ventilation (DV) Ventilation, mechanical See also specific topics complications of, 973–987 (See also Complications, of ventilation; specific ventilation techniques) delivery of, invasive vs noninvasive, 125 goals of, 49, 50t home (See Home mechanical ventilation) indications for (See Indications, for ventilation) objectives of, 49, 50t Ventilation-induced pulmonary edema, microvascular permeability in, 998–1000, 999f–1000f Ventilation–perfusion inequality, in weaning failure, 1319 Ventilation–perfusion matching, prone and supine positioning on, 1174 Ventilation without overinflation, on previously injured lungs, 1009–1010 Ventilator anesthesia, 604–608 available models of, 609t circle system in, 604, 607f cycling mechanism in, 604 design of bellows, 607–608, 607f piston, 608, 608f turbine, 608 driving mechanism in, 604 history and use of, 604 power source for, 604 artificial-intelligence–operated, for weaning, 1308f, 1344–1345 automatic transport, for resuscitation, 663 computerized, for weaning, 1308f, 1344–1345 critical care selection of for acute care, 476–477 for chronic care, 477 fighting (See Fighting the ventilator) high-frequency, neonatal and pediatric, 587–588 humidifying cascades in, in ventilatorassociated pneumonia, 1096–1097 negative-pressure cuirass, 418 jacket ventilators, 418 tank ventilators, 417–418, 419f neonatal and pediatric, 587–588 portable, 674 for transport, 674 removing dying patients from, 1473–1482 (See also Ethics, of withholding and withdrawing ventilation) sleep disruption from, 1299–1300, 1300f Ventilator, mechanical See also specific types and topics automated, challenge of, 62, 63f components of, 45 computer control of, total, 62, 63f computerized, for weaning, 1308f, 1344–1345 definition of, 65 energy for, 45 future of, 62, 63f hand, origins and early use of, 33–34, 34f Janeway, 30, 30f modes of, comparing, 57, 60t negative-pressure early, 21, 25f history of, 20–21, 21f–26f outline of, 46t quality control of, history of, 36 volume-cycled, Bowditch, 22, 27f 1559 Ventilator, transport, 674–679 attributes of, 677–678 automatic resuscitator, 674–675, 675f definition of, 674 performance issues in, 678–679, 679f simple, 675, 675f, 676f sophisticated, 675–677, 676f, 677f Ventilator-associated lung injury See Ventilator-induced lung injury (VILI) Ventilator-associated pneumonia (VAP), 1091–1112 after tracheotomy, 948–949 in chronic obstructive pulmonary disorder, from ventilator assistance, 752 definition of, 1091–1092 diagnosis of, 1097–1104 distal specimens in, quantitative cultures of bronchoscopy-obtained, 1100–1102, 1100f, 1101f not bronchoscopy-obtained, 1102 endotracheal aspirates in qualitative cultures of, 1098–1099, 1098f quantitative cultures of, 1099 in patients on antimicrobials, 1102 procalcitonin and other biologic markers in, 1103 radiography in, 1098 “Singh” strategy in, 1099, 1099f steps in, 1098 summary of evidence in, 1100f, 1103 systemic signs in, 1097–1098 epidemiology of, 1091–1094, 1447 etiologic agents in, 1092–1094, 1093t incidence in, 1092 mortality, morbidity, and cost in, 1092 in neonates and children, 590–591 nosocomial sinusitis and, 1126 pathogenesis of, 1094 prevention of, 1108–1112 conventional infection control in, 1108–1109 rationale for, 1108 specific prophylaxis in, 1109–1112 antiseptic oral decontamination in, 1110 endotracheal tubes in, specialized, 1110 enteral feeding methods in, 1111 oscillating and rotating beds in, 1109–1110 semirecumbent positioning in, 1109 stress-ulcer prophylaxis in, 1111 structured prevention policy in, 1111–1112 subglottic secretion aspiration in, 1110 ventilator circuit management in, 1110–1111 risk factors in, 1094–1097 antimicrobial agents, 1095 endotracheal tube, reintubation, and tracheotomy, 1096 intrahospital patient transport, 1097 nasogastric tube, enteral feeding, and patient position, 1096 respiratory equipment, 1096–1097 sinusitis, 1097 stress-ulcer prophylaxis, 1095 surgery, 1094–1095 1560 Index Ventilator-associated pneumonia (VAP) (Cont’d.) from translaryngeal intubation, 907–908 treatment of, 1104–1108 aerosolized therapy in, 1107–1108 focusing therapy with infectious agent identification in, 1105–1106 initial therapy in, 1104–1105, 1104t optimizing antimicrobial therapy in, 1106 shortening therapy duration in, 1107 stages in, 1104 stopping therapy with unlikely diagnosis in, 1105 switching to monotherapy at days 3-5 in, 1106–1107 Ventilator-associated sinusitis, 1097 See also Sinus infections (sinusitis) maxillary antibiotic treatment of, 1133 diagnosis of, 1130, 1131f prevention of, 1130 treatment of, 1133 Ventilator-dependent patient, 780 Ventilator-dependent tetraplegia, diaphragmatic pacing for, 1410–1411, 1411f Ventilator design principles, 65–95 alarms in, 90–91, 91f future of, 92–95 operator interfaces in, 92 patient interfaces in, 93 targeting systems in, 93–95, 95f operator interface in, 72–91 (See also Operator interface) outputs (displays) in, 91–92, 92f–94f advanced graphics, 91–92, 93f, 94f numeric values, 91, 92f trends, 91, 92f waveforms and loops, 91, 93f positive end-expiratory pressure in, 89–90, 90f ventilator as “black box” in, 65–72 appearance of, 66f automation in, 65 basic design in, 65 complexity and examples of, 65, 66f conversion and control of, 68 control systems in, 69, 69f flow-control valves in, 68, 68f, 69f inputs of, 68 outputs of, 69–72 idealized pressure, volume, and flow waveforms in, 69–70, 70f patient circuit on, 70–72 targeting schemes on, 57, 60t pneumatic schematic of, 65, 67f Ventilator-induced atrophy, 1025–1030, 1026f Ventilator-induced diaphragm dysfunction (VIDD), 161, 1025–1038 clinical context in, 1035–1036 definition of, 1025 epidemiology of, 1025 evidence for, 1025 future of, 1037 pathophysiology of atrophy in, 1025–1030, 1026f autophagy–lysosome pathway in, 1028–1030, 1029f calpains in, 1027, 1027f caspases in, 1027–1028, 1028f evidence for, 1025–1027, 1026f proteasome in, 1030, 1030f–1032f diaphragmatic force and endurance in in humans, 1033, 1035f in intact animals, 1035, 1035f in vitro, 1035 drugs in, 1035 oxidative stress in, 1030–1033, 1033f structural injury in, 1033, 1034f prevention of intermittent diaphragmatic contractions in, 1036 pharmacologic, 1036–1037, 1037f ventilator strategy in, 1036, 1036f recovery from, 1037 unknowns in, important, 1037 Ventilator-induced hyperinflation, from ventilator assistance in chronic obstructive pulmonary disorder, 752 Ventilator-induced lung injury (VILI), 377, 547, 995–1019 in acute respiratory distress syndrome multisystem organ dysfunction and, 721 pathogenesis and detection of, 720–721 clinical relevance of, 1017–1019 definition of, 1042 future directions and research on, 720–721 history of, 995–996 inflammation activation in, 1002–1003, 1003f mechanisms of, 704, 704f, 996–1001 filtration increase in, 996–997, 997f permeability alterations in, 997–1001 alveolo-capillary permeability in lung overinflation in, 1000–1001, 1001f epithelial permeability in, high airway pressure on, 997–998, 997f, 998f microvascular permeability in, in ventilation-induced pulmonary edema, 998–1000, 999f–1000f multisystem organ dysfunction and, 721 in normal lung regions, 1010–1011, 1011f, 1012f pathophysiology and prevention of, 704–712 mechanostress and mechanosignaling in, 704–706, 705f, 706f pathogenetic cofactors in, 707–708, 708f, 708t, 709f positive end-expiratory pressure in, 708–710, 709f recruiting maneuvers in, 710–712, 710f–712f, 710t (See also Recruitment maneuvers) spontaneous ventilator efforts in, 712 tidal volume and tissue stress in, 706–707, 707f, 708f pathophysiology of, 265–266, 266f permissive hypercapnia for, 385–386, 385f physiologic determinants of, 1003–1007 increased airway pressure and lung volume in, 1003, 1005f pressure–volume change magnitude and duration of challenge in, 1003–1004, 1005f sustained inflation (PEEP) and large pressure–volume swings in, 1004–1007, 1006f, 1007f positive end-expiratory pressure on, 266–267, 266f protection from, 1011–1017 hypercapnia in, 1017 lung mechanics improvement in, 1011–1014 noisy ventilation in, 1014 perfluorocarbons in, 1012–1013, 1013f pressure–volume curves in, 1008f, 1011–1012 prone position in, 1013–1014 surfactant in, 1012 pharmacologic interventions in, 1014–1017 for hormonal and metabolic pathways, 1016–1017 for inflammation, 1015–1016, 1015f for microvascular permeability, 1014–1015, 1014f strategies for, 495 reflex feedback on, 813–814, 814f in remote organs, 1010–1011 in surgery and general anesthesia, 601–603 tidal volumes in, high, 1276 ultrastructural findings in, 1001–1002, 1002f–1004f ventilation ffects on previously injured lungs in, 1007–1010 high-volume–high-pressure ventilation and previous injury in, 1007–1009, 1007f–1009f ventilation without overinflation in, 1009–1010 Ventilator malfunction, fighting the ventilator from, 1249–1256 of external ventilator circuit, 1249 inspiration–expiration switching in, 1253–1254, 1254f inspiratory unloading in, mode-specific effects of, 1253, 1253f patient–ventilator dyssynchrony in, 1249–1253 double triggering in, 1251–1252, 1251f, 1252f ineffective triggering in, 1246f, 1250–1251 inspiratory flow setting in, 1252–1253, 1252f, 1253f mechanisms of, 1249–1250 sleep–wake state in, 1242f, 1254–1256, 1255f ventilator triggering in, 1250, 1250f Ventilator mode in barotrauma, 1045–1046, 1045t, 1046t on lung deposition of inhaled antibiotics, 1449 Ventilator pumps, negative-pressure, 418–419, 420f Ventilator rate, entrainment of respiratory rate to, 815 Ventilator response time, in proportional-assist ventilation, 339 Ventilator settings See also specific ventilators and ventilation types in barotrauma, 1045–1046, 1045t, 1046t for dyspnea, 1274–1276 in chronically ventilator-dependent patients, 1276 control mode on, 1274f, 1275 level of ventilator support in, 1274–1275, 1274f Index positive end-expiratory pressure level on, 1275 rate of inflation on, 1275 studies on, 1274 unwanted effects of ventilator adjustments in, 1276 on lung deposition of inhaled antibiotics, 1449 monitoring for optimization of, 1151–1152, 1152f Ventilator triggering See Triggering Ventilatory drive, 1270 Ventilatory failure See also specific disorders acute, 793 acute-on-chronic, 793 definition of, 520 time course of, on blood-gas differences, 687, 687t Ventilatory insufficiency, 684, 684f See also specific disorders Ventilatory patterns, 57 See also specific patterns Ventilatory pump failure, in obstructive lung diseases, ventilator settings for, 153–154 Ventricular diastolic interdependence, 824–825, 825f Ventricular interdependence on lung volume in mechanical ventilation, 824–825, 825f positive end-expiratory pressure on, 268 Vent status lung panel, 92 Venturi mask, 36 Verbal dialogue, for psychological diagnosis, 1261 Vertical inflation gradient mechanism in acute respiratory failure, 1171 in normal lungs, 1170, 1170f Vesalius on heart and lung physiology, on positive-pressure ventilation, 22 on ventilation during vivisection, 18 Vibrating mesh nebulizers, 1425–1426 Vibrating plate nebulizers, for inhaled antibiotics, 1449 Video laryngoscopy, 883, 883t for mechanical ventilation in resuscitation, 664 Virus-induced hypoxemic failure, pediatric, 580 Vital capacity, in weaning outcome, 1334–1335 Vitamin C for oxygen toxicity, 1082 prophylactic, on ventilation duration, 1037 Vitamin E as antioxidant, 1079 for oxygen toxicity, 1081–1082 prophylactic, on ventilation duration, 1037 Vivisection, history of ventilation in, 17–18 Vocal control mechanisms, 366 Vocal cord granuloma, 903f, 904–905, 906f Vocal cord hematoma from endotracheal tube, 897 postextubation, 911 Vocal cord paresis and paralysis postextubation, 911 from translaryngeal intubation, 904 Voice, after tracheotomy, 954–959 electrolarynx for, 958t, 959 fenestrated tracheotomy tube for, 959 phonation valves for, 958t, 959, 959f pneumatic speaking tubes for, 954, 959 techniques and methods for, 954, 956t–958t Voice tracheostomy tube, 1289 Volatile halogenated anesthetics, on breathing control, 598 Volume, as trigger variable, 76–77 Volume, lung, 45–46 Volume assist-control ventilation (VACV), in general anesthesia, 602t Volume-assisted pressure support, 142–143 Volume control, 52, 143 Volume-controlled ventilation (VCV) with AutoFlow, in general anesthesia, 602t classification of, 228 control variables in, 46–47 definition of, 57 in general anesthesia, 602t neonates and infants, 584 vs pressure-controlled ventilation, 234f, 235f, 237–238 speech with, 1283, 1284f Volume cycle, 48–49 Volume-cycled ventilation, 228 Volume-cycled ventilator, Bowditch, 22, 27f Volume cycling, in operator interface, 88 Volume-dependent pulmonary resistance changes, on lung volume, 824, 824f Volume overload prevention, during weaning, 843 Volume preset controlled mechanical ventilation, 140 Volume-preset mode, 141, 141f Volume-preset ventilation, 141, 141f Volume support, 143 Volume-support ventilation (VSV), vs intermittent mandatory ventilation, 190 Volume-targeted ventilation (VTV), in neonates and infants, 577–578, 584–585 Volume–time profile, variables in, 805–806, 806f Volutrauma, 500, 603 Vomiting, 366 von Guericke, Von Hauke, 20 Von Helmont, von Humboldt, 14 von Schrotter, 15–16 Vortran, 674–675, 675f W Ward general, 793 noninvasive ventilation on, 793–800 (See also General ward, noninvasive ventilation on) Wasted work, 1272 Water See also Humidification excess, 1201 sterile, airway suctioning, 1226 Water balance, 1459–1460, 1460t Waveforms See also specific types display, 91, 93f 1561 Weakness intensive care unit–acquired, 1505, 1506f, 1506t muscle after critical illness, 1505, 1506f, 1506t in chronic obstructive pulmonary disease, 743 Weaning, 1307–1347 See also specific disorders and types of ventilation after tracheotomy, 959–960, 960f in chronic obstructive pulmonary disease exacerbations, on gas exchange, 861–862, 862f chronic ventilator facilities for, outcomes and effectiveness of, 785–788, 786t, 787t definition of, 1307 history of, 36–37 in ICU, 778 intermittent mandatory ventilation for, 190–193 vs adaptive-support ventilation, 192–193 with intermittent T piece, 190–192, 191t vs mandatory minute ventilation, 192 vs pressure-support ventilation, 190, 191t vs synchronized IMT, 191–192, 191t in neonates and children, 581–582, 581t in neurally adjusted ventilatory assist, 363, 368 noninvasive positive-pressure ventilation for, 460 noninvasive ventilation for, 1366–1367 off extracorporeal life support, 535 outcomes in, predicting, 1319–1330 Bayesian analysis of f/VT reported performance in, 1325t, 1328–1329, 1328f, 1329f Bayes’ theorem on, 1323–1324 decision analysis principles in, 1319–1322, 1321f Evidence-Based Medicine Task Force on weaning in, 1322–1323 pretest probability of success in, 1324, 1324f, 1325t sequential diagnostic testing in, 1324–1326, 1326f spectrum bias and test-referral bias in, 1326–1328, 1327f tailoring predictor to patient needs in, 1329–1330 pressure-support ventilation for, 218–219 with noninvasive ventilation, 219 with proportional-assist ventilation, 333 seven stages of, 1307–1309, 1308f sleep deprivation on, ICU, 1301 System One errors in, 1308 techniques of, 1337–1347 computerized approaches to, 1308f, 1344–1345 head-to-head comparisons of, 1340–1342 intermittent mandatory ventilation in, 1338 PEEP replacement of physiologic PEEP in, 1340 physical and occupational therapy in, 1346 pressure support in, 1338–1339 protocol vs usual care in, 1342–1344, 1344f respiratory muscle training in, 1345–1346 sedation in, 1346–1347 spontaneous breathing trials in, 1340 T-tube trials in, 1339–1340, 1339f two-step strategy in, 1337–1338 1562 Index Weaning (Cont’d.) transtracheal gas insufflation for, 559–561 usual methods of, 218 from ventilation in chronic obstructive pulmonary disorder with invasive ventilation, 753 with noninvasive positive-pressure ventilation, 753 volume overload prevention in, 843 weaning outcomes in, predicting, 1330–1337 airway occlusion pressure in, 1335, 1335t arterial blood-gas values in, 1333 B-type natriuretic peptides in, 1336–1337 frequency-to-tidal-volume ratio in, 1330–1333 comparison of, with other diagnostic tests, 1332, 1333t randomized, controlled trial of, 1332–1333 technical details of, 1308f, 1330–1332, 1330f–1333f gastric tonometry in, 1336 maximum inspiratory pressure in, 1334, 1334t minute ventilation in, 1333–1334, 1334t standard predictor reproducibility in, 1314f, 1335–1336 vital capacity in, 1334–1335 Weaning failure on heart–lung interactions, 833 pathophysiology of, 1309–1319 cardiovascular performance in, 1316–1319, 1318f control of breathing in, 1309–1310, 1310f gas exchange in, 1319 history of, 1309 patient effort in, 1311–1312, 1312f–1314f respiratory mechanics in, 1310–1311, 1310f respiratory muscles in, 1313–1316, 1315f–1317f Weaning-predictor tests development of, 1322 evaluation of reliability of, 1328 ideal, characteristics of, 1320–1322 for postextubation distress, 1358–1359 purpose of, 1322 Well-being, 1260 “Wet” lung See Acute respiratory failure (ARF) Wheezing, 121 Whole-lung lavage, independent lung ventilation for, 637–638, 637f Williams, 31 Withholding and withdrawing ventilation ethics of, 1473–1482 (See also Ethics, of withholding and withdrawing ventilation) to terminally ill, for cost control, 1497 Within-breath targets, 77 Woillez, 20, 22f Work of breathing See Breathing, work of Wound infection, stoma, after tracheotomy, 948 Wound repair, epithelial, permissive hypercapnia on, 384 Written communication, 956t X X15 aircraft, 17 XC-35 aircraft, 16, 17f Xerxes, 11 Z Zero end-expiratory pressure (ZEEP), 260 Zero offset error, 1143 Zileuton, 1424 ... CO2 and O2 in mixed pulmonary capillary blood, respectively; ΔPchCO2 and ΔPchO2, the difference in partial pressure of CO2 and O2 at chemoreceptors (peripheral and central), respectively; Ers and. .. titration of tidal volume based on individual lung mechanics may be a better Chapter 35 Effects of Mechanical Ventilation on Control of Breathing 815 40 35 PPLATpav (cm H2O) 30 25 20 15 10 – 12 12 24... Mechanics of Respiratory System 0.8 25 20 15 10 20 15 10 –5 Flow (L/s) Pes (cm H2O) Paw (cm H2O) 0.8 0.6 0.4 0 .2 –0 .2 –0.4 –0.6 –0.8 Pes (cm H2O) Flow (L/s) The mechanical properties of the respiratory