(BQ) Part 2 book Critical care of the stroke patient has contents: Respiratory care of the ICH patient, nutrition in the ICH patient, intraventricular hemorrhage, interventions for cerebellar hemorrhage, craniotomy for treatment of aneurysms,... and other contents.
Cambridge Books Online http://ebooks.cambridge.org/ Critical Care of the Stroke Patient Edited by Stefan Schwab, Daniel Hanley, A David Mendelow Book DOI: http://dx.doi.org/10.1017/CBO9780511659096 Online ISBN: 9780511659096 Hardback ISBN: 9780521762564 Chapter 21b - Respiratory care of the ICH patient pp 286-296 Chapter DOI: http://dx.doi.org/10.1017/CBO9780511659096.027 Cambridge University Press 21b Respiratory care of the ICH patient Omar Ayoub and Jeanne Teitelbaum Introduction Indications for intubation and ventilation The overall incidence of intracerebral hemorrhage (ICH) is estimated to be 12–15 cases per 100000 population [1] ICH represents around 15–30% of the overall stroke admissions to the hospital and results in significant disability, morbidity, and 30–50% mortality [2] The most common cause of death in patients admitted with ICH was found to be withdrawal of lifesustaining interventions, and this accounted for 68% of the overall mortality Indeed, the frequency of use of ‘do not resuscitate’ orders is highly associated with the odds of dying in hospital from ICH [3] When aggressive management is instituted, patients who are treated in the neurologic intensive care unit have a lower mortality rate than those hospitalized in a general ICU [4] The effect on morbidity, however, is related to the cause of respiratory failure When the problem is that of incomplete airway protection due to structural weakness or dysfunction, the intubation and ventilation will improve both morbidity and mortality; when intubation and ventilation are instituted because of a low GCS, the aggressive approach to ventilation will not change overall outcome [5] This chapter will address airway assessment and management in the critically ill patient with ICH, focusing on methods of assessment, indications for intubation, ventilation and tracheostomy, methods of ventilation, and the indications and implementation of successful weaning from the ventilator Among patients admitted to ICUs, 20% will have an acute neurological disorder as the principal indication for instituting mechanical ventilation (MV), with half of these patients receiving MV for neuromuscular disease and the other half for coma or central nervous system dysfunction [6] Ventilatory support is needed to maintain proper oxygenation to tissues, particularly the injured brain cells, in order to prevent further neurologic and systemic injury resulting from hypoxia or hypercapnea The decision to intubate and mechanically ventilate the patient depends on the clinical picture, even before imaging The general indications for intubation in this particular subset of patients includes decreased level of consciousness with a GCS of or less, raised ICP, inability to protect the airway, anticipation of decline, co-existing pulmonary indications and as a temporizing measure prior to surgical intervention In the next sections, we will go over the different indications and physiological rationale for intubation and MV in patients with ICH Decreased respiratory drive The major causes for decreased respiratory drive after ICH are a decreased level of consciousness (LOC) and damage to the brainstem with or without abnormal Critical Care of the Stroke Patient, ed Stefan Schwab, Daniel Hanley, and A David Mendelow Published by Cambridge University Press © Cambridge University Press 2014 286 Downloaded from Cambridge Books Online by IP 216.195.11.197 on Thu Nov 05 23:26:57 GMT 2015 http://dx.doi.org/10.1017/CBO9780511659096.027 Cambridge Books Online © Cambridge University Press, 2015 Chapter 21b: Respiratory care of the ICH patient LOC Regardless of the cause of encephalopathy, there is an association between reduced level of consciousness and depression of the respiratory drive, hypoventilation and lack of airway protection [7] Although the main reason for coma would be through intracranial hypertension (ICHT) and subsequent herniation, this could occur with normal or only slightly increased ICP as well The causes of coma without ICHT include brainstem hemorrhage, cerebellar hemorrhage, relatively small mesial temporal hemorrhage with uncal herniation but without massive change in global ICP, and concomitant toxic or metabolic encephalopathy For the obtunded or comatose patient with decreased respiratory drive, intubation is not only to maintain airway but also to provide ventilation If there is increased ICP, ventilation assures not only normocapnea but is used as a method to lower ICP through hyperventilation High ICP Mechanical ventilation is used routinely in the management of high ICP to correct hypoxemia, hypercarbia, and acidosis that usually occur in conjunction with intracranial hypertension Almost invariably, these patients require MV because of the accompanying decrease in their level of consciousness The high ICP seen in hemorrhagic stroke is due to the mass effect of the hematoma as well as the surrounding edema MV in this scenario is used not only to protect the airway and assure oxygenation but also to stabilize and reduce ICP Hyperventilation If there is clinical or objective evidence of herniation, therapeutic hyperventilation is indicated and proven effective in ICH while completing the investigation and beginning other methods of ICP reduction CO2 is a potent modulator of CBF and hence of ICP Hypocapnea results in vasoconstriction of the cerebral vessels, and as a result CBF and CBV will decrease leading to a decrease in ICP The range in which PaCO2 has the greatest impact on cerebral vessel caliber is 20–60 mmHg Within this range, CBF changes 3% for every mmHg change in PaCO2 [8] A decrease in CO2 tension by 10 mmHg can produce sufficient reduction in CBV to effect a profound decrease in ICP Experimental studies have shown that the change in caliber of blood vessels is a direct effect of extracellular pH rather than an effect of CO2 or bicarbonate [9] This explains the lack of efficacy of prolonged hyperventilation in the treatment of high ICP, as the extracellular pH of the brain tends to normalize within hours (10–20 hours) of therapy, with rebound vasodilatation when hyperventilation is discontinued [10] Current guidelines recommend against prophylactic hyperventilation, and therapeutic hyperventilation should be used only for short periods of time, targeting a modest reduction in PCO2 to approximately 30 to 35 mmHg [11] Lower levels of CO2 may result in brain hypoxia, but results are very contradictory, and during the hyper-acute phase of herniation, there is likely no danger in temporarily decreasing PCO2 as low as 25 mmHg [12,13] The present guidelines not address exact length of use, exact mechanical parameters, or the duration of hyperventilation Eminence-based recommendations are as follows: Use in the presence of severe ICHT, as a first measure while instituting osmotic agents and assessing the use of other measures (decompression, EVD) The PCO2 should be lowered by at least 10 mmHg to reach a level of 30 mmHg Go to 25 mmHg of PCO2 if there is still uncontrolled ICHT Set the ventilator to give tidal volumes of 12–15 cc/kg at a rate of 12–14 breaths per minute while monitoring blood gases and end-tidal CO2 If the goal is not attained, increase the rate as necessary to 16 and up to 20 per minute Work quickly, as the effect is almost immediate and the dangers of herniation may be imminent Hyperventilation is a temporizing measure, to be used for impending herniation and removed as soon as other measures of ICP control have been instituted If used for less than hour, it can be stopped without worry of rebound If in place for more than hours, weaning must be progressive to avoid rebound Prolonged hyperventilation, and levels below 25 mmHg for days, are deleterious, especially in trauma Downloaded from Cambridge Books Online by IP 216.195.11.197 on Thu Nov 05 23:26:57 GMT 2015 http://dx.doi.org/10.1017/CBO9780511659096.027 Cambridge Books Online © Cambridge University Press, 2015 287 288 Chapter 21b: Respiratory care of the ICH patient Poor airway protection This is often seen in conjunction with abnormal drive in the comatose patient, but can be seen in isolation as well In the comatose patient, the oropharyngeal muscle tone is significantly decreased, leading to posterior displacement of the tongue and airway obstruction [14] As well, airway patency may be compromised by foreign objects, secretions, orofacial fractures, or soft tissue edema that are associated with cervical injuries, on top of traumatic ICH In addition to damage due to ICH, patients may have associated systemic disorders that can compromise ventilation and oxygenation, such as drug or alcohol overdose, aspiration pneumonia, pulmonary contusions, fat emboli, pneumothorax, flail chest, and pulmonary edema Even without intracranial hypertension or lowered level of consciousness there can be an impaired ability to protect the airway and to assure ventilation This can occur with brainstem or hemispheric damage Extensive hemispheric damage can lead to dysphagia with aspiration and eventual respiratory insufficiency If continuous aspiration is occurring despite nasogastric feeding and suction, the airway will need to be protected by intubation and possibly tracheostomy if the situation does not improve Ventilation is only necessary if pneumonia is severe and impedes spontaneous efficient breathing Brainstem hemorrhage affecting the dorsomedial and ventrolateral medulla will affect the centers for automatic respiratory drive and rhythmic breathing, leading to hypoventilation A lesion in the pontine pneumotaxic centers on the other hand can impair the ability to modulate respiratory frequency, and fine control of the respiratory function [14] Aerodynamic studies of patients with brainstem stroke show abnormal inspiration phase volume, peak inspiratory flow, duration of glottic closure, and delayed onset to peak of the expulsive phase, all of which can contribute to ineffective cough and an increased risk for aspiration pneumonia [15] Also, through damage to the cranial nerves and their nuclei, patients with brainstem dysfunction have marked abnormalities of their cough reflex, swallowing, and phonation, all of which can affect respiration indirectly or lead to complications that mandate prolonged respiratory support Anticipation of decline On occasion, it may be necessary to intubate and ventilate a patient prior to the onset of respiratory distress, to avoid aspiration, hypoxia, and worsening intracranial hypertension in a patient that is actively deteriorating or very likely to so Although intubation does have associated risks (hypotension, esophageal intubation, aspiration) and it is known to be associated with longer ICU stay, these complications are even more frequent if the intubation is done in a hurried fashion in a decompensated patient A patient who presents early after an ICH and is already showing a change in level of consciousness, or in whom there is already some degree of shift and hydrocephalus on CT is likely to require this type of early intubation Pulmonary indications Patients who have acute neurologic disorders are at increased risk for major pulmonary complications [16] These include: risk of pneumonia, pulmonary embolism, hypoxemic respiratory failure, neurogenic pulmonary edema, and acute respiratory distress syndrome (ARDS) Also, early intubation may be required in the subset of patients who have pre-existing pulmonary disease, who may get cardiopulmonary decompensation as a result of overlying acute brain process [17] Types of intubation and ventilation available The standard method of establishing a patent airway is by orotracheal intubation, but other techniques can be used These include: Bag-valve mask ventilation BIPAP Nasotracheal intubation Laryngeal mask Surgical cricothyrotomy Oro-tracheal intubation Downloaded from Cambridge Books Online by IP 216.195.11.197 on Thu Nov 05 23:26:57 GMT 2015 http://dx.doi.org/10.1017/CBO9780511659096.027 Cambridge Books Online © Cambridge University Press, 2015 Chapter 21b: Respiratory care of the ICH patient It is crucial to have a good assessment of the airway looking for signs of difficulties ‘Difficult airway’ is defined by the American Society of Anesthesiology as the existence of clinical factors that complicate either ventilation using face-mask or intubation performed by an experienced clinician In most cases, oro-tracheal intubation will be accomplished using rapid sequence intubation technique (RSI) The purpose of RSI is to quickly and effectively induce unconsciousness and paralysis using a specific sequence of drug therapy When compared to intubation without paralysis, it reduces the incidence of complications such as aspiration and traumatic injury to the airways [18] The sequence or RSI can be summarized in the ‘seven Ps’: Preparation for the procedure, Preoxygenation, Premedication, Paralysis, Protection by Sellick maneuver, Placement of the tube, and Postintubation management Preparation: includes rapid assessment of the patient, collecting the necessary drugs and equipment needed for the procedure Pre-oxygenation or alveolar de-nitrogenation is implemented to create a reservoir of oxygen in the lungs that prevents desaturation during attempts of intubation Give 100% oxygen by non-rebreathing mask if awake, or by bag-valve mask ventilation if not Premedications: these are used to reduce the adverse physiological response of laryngoscopy LOAD (lidocaine, opioids, atropine, and a defasciculating dose of paralytic agent) is the mnemonic to summarize the agents used for this purpose i Lidocaine of 1.5 mg/kg is used to attenuate the cardiovascular response to intubation, suppress the cough reflex, and mitigate the ICP response to intubation [19,20] ii Opioids, specifically fentanyl, reduce the sympathetic response to intubation on top of its analgesic and sedative effect [21] iii Atropine is usually used in children to blunt the vagal response and bradycardia that occur as a result of laryngoscopy iv For paralysis, a small defasciculating dose of non-depolarizing paralytic agent (e.g rocuronium) can be used prior to the administration of succinylcholine to reduce fasciculations and the associated increase in ICP that results from it It is not clear that this increase in ICP actually affects outcome [22] Induction: After giving the LOAD, sedation is accomplished by the administration of an induction agent, followed by either depolarizing or non-depolarizing paralytic agent There are many induction agents that can be used with different side effect profiles and pharmacological properties Clinicians should have detailed knowledge of their properties as the choice of the right agent will depend on the clinical scenario i Propofol: rapid acting, lipid soluble induction agent that induces hypnosis on top of its anticonvulsive and antiemetic properties It is known to depress the pharyngeal and laryngeal muscle tone and reflexes more than any other agent and may be used with opioids alone when neuromuscular paralysis is contraindicated [23] It has the ability to reduce the ICP by decreasing intracranial blood volume and cerebral metabolism [24] These mechanisms may underlie the improved outcome with its use in patients with high ICP in the setting of traumatic brain injury [25] Propofol has no analgesic properties, and the major side effect is drug-induced hypotension by its action on systemic vascular resistance Hypersensitivity reaction can occur in patients with egg/soy allergy ii Etomidate: this is a non-barbiturate hypnotic agent that has a rapid onset of action, short duration, minimal histamine release after administration, and little or no effect on the systemic BP [26] Disadvantages include the inability to blunt the sympathetic response, lowering seizure threshold, high incidence of myoclonus, occurrence of nausea and vomiting, and suppression of the adrenal glands It is widely used as an induction agent in patients with polytrauma given the lack of effect on systemic BP (It is used less often in patients with high ICP because of the availability of other agents that blunt the sympathetic response in intubation, but in general it is safe to use) Downloaded from Cambridge Books Online by IP 216.195.11.197 on Thu Nov 05 23:26:57 GMT 2015 http://dx.doi.org/10.1017/CBO9780511659096.027 Cambridge Books Online © Cambridge University Press, 2015 289 290 Chapter 21b: Respiratory care of the ICH patient iii Ketamine is a phencyclidine derivative that has a rapid onset of action with amnestic, analgesic, and sympathomimetic properties It does not abate airway-protective reflexes or spontaneous ventilation and it causes bronchodilation [27] A recent review of the literature shows that ketamine can be used safely in patients with high ICP as long as patients are sedated and properly ventilated [28] iv Sodium thiopental is a good choice for patients with status epilepticus or increased ICP because of its cerebroprotective effects It causes cerebral vasoconstriction, reduces cerebral blood volume, and decreases ICP [29] The major drawback of its use is the systemic hypotension that occurs with it v Midazolam can be used as an induction agent and has anticonvulsant properties It could cause hypotension with high doses Paralysis: after the injection of the induction agent of choice, a paralytic drug should be given and should be tailored to the clinical situation We present some of the data about paralytic agents and the advantages versus disadvantages of each of them i Depolarizing drugs: these agents act on the acetylcholine receptors as agonists, causing prolonged depolarization and resulting in muscle relaxation after a brief period of fasciculation Succinylcholine is the prototypical drug of this class that has a rapid onset of action (30–60 seconds) and short duration of action (5–15 minutes) Spontaneous respiration may return 9–10 minutes after its use It is usually degraded by plasma and hepatic pseudocholinesterases Succinylcholine is given in a dose of 1.5 mg/kg because lower doses could cause relaxation of the laryngeal muscles before skeletal muscles, which could complicate intubation and put the patient at risk of aspiration The side effect profile includes hyperkalemia, malignant hyperthermia and increased ICP [30,31] It should be avoided in diseases that have upregulation of the acetylcholine receptors as it may cause an exaggerated release of potassium These disorders include stroke, multiple sclerosis, muscular dystrophies, GBS, and others Based on the side-effect profile and the extensive risks imposed, some intensivists discourage its use with critically ill patients in the ICU [32] ii Non-depolarizing agents such as rocuronium: these agents act by blocking acetylcholine receptors at the neuromuscular junction It has a short onset of action (1–2 minutes), longer duration of activity (45–70 minutes), and the usual dose is mg/kg They not have the side-effect profile of depolarizing agents and have been used as a substitute when the other class is contraindicated In a systematic review, the use of succinylcholine was compared to rocuronium in intubation procedures The reviewers found that the use of succinylcholine resulted in a superior intubation condition compared to rocuronium when rigorous standards were used to define excellent conditions When these standards were less rigorously used to define adequate conditions, and when propofol was added as an induction agent, the two drugs had similar efficacy The success rate of intubation was the same for both groups under all circumstances [33] Sellick maneuver: is performed by applying pressure on the cricoid to prevent passive aspiration and gastric insufflation Placement of the endotracheal tube (ETT): this should be done under direct visualization of the vocal cords By applying pressure at the thyroid cartilage the field of visualization can be improved As mentioned before, preparation is the best way to intubate patients who are critically ill, especially when it comes to passing the ETT Different devices are of help in passing the ETT into proper position that should be kept around the intubating field especially in the neuroICU setting A lighted stylet, gum elastic bougie, laryngeal mask airway, or fiberoptic machine should be ready whenever needed, especially if there is an anticipation of difficult airway These devices decrease the incidence of failed intubations and could be used when direct laryngoscopy is contraindicated or difficult [34] Downloaded from Cambridge Books Online by IP 216.195.11.197 on Thu Nov 05 23:26:57 GMT 2015 http://dx.doi.org/10.1017/CBO9780511659096.027 Cambridge Books Online © Cambridge University Press, 2015 Chapter 21b: Respiratory care of the ICH patient Modes of mechanical ventilation Basically, there are modes of ventilation that breathe for the patient and others that assist the patient and allow the initiated breath to be large enough to assure adequate ventilation Controlled modes of ventilation: these will dictate the frequency of the ventilation as well as either the volume of the breath (volume control), or the pressure at which the air is sent (pressure control) The patient’s own respiratory rate does not affect the frequency of the delivered breaths, and the volume or pressure remain constant, not taking into account lung compliance In a conscious or semi-conscious patient with some residual muscle strength, this can result in the patient fighting the ventilator If the lungs are very stiff, fixed volume might lead to unacceptably high lung pressures and pneumothorax Fixed ventilation is used in patients who have no respiratory drive or who are paralyzed Fixed pressures are used in patients with such stiff lungs that must not receive air pushed in above a specific threshold of pressure, even if this leads to hypercarbia Assisted modes of ventilation: in this case the patient initiates the breath and the machine assists and maximizes tidal volume by supplying a set volume or a set inspiratory pressure i SIMV stands for synchronized intermittent mandatory ventilation The machine will deliver a set number of breaths but will synchronize them with the patient’s efforts and supply breaths when the spontaneous rate is below the set rate For spontaneous breaths, the work of breathing is decreased by providing a pressure support So, when on SIMV mode, the patient receives three different types of breath: – the controlled mandatory breath; – the assisted breath; and – the spontaneous breath that can be pressure supported ii PS or pressure support can be used as a partial or full support mode The patient controls all parts of the breath except the pressure limit The patient triggers the ventilator – the ventilator delivers a flow up to a preset pressure limit (for example 10 cmH2O) depending on the desired minute volume, the patient continues the breath for as long as they wish, and flow cycles off when a certain percentage of peak inspiratory flow (usually 25%) has been reached Tidal volumes may vary, just as they in normal breathing The level of pressure support is set at the pressure that assures an adequate tidal volume In patients with neurological rather than pulmonary disease and preservation of respiratory drive, PS is the best choice for ventilation If respiratory drive is compromised, SIMV works well Many other considerations are involved when the main issue is pulmonary Parameters of ventilation The literature on respiratory care and mechanical ventilation in patients with ICH is scarce Few trials have addressed this issue, and until now we not have guidelines for the exact parameters that should be implemented for the management of this population Most of the current practice recommendations are based on evidence from brain trauma trials and on expert opinion The recommendation by The Brain Trauma Foundation for oxygenation and ventilation in brain injury patients is to prevent hypoxia by maintaining PaO2 >60 mmHg and arterial oxygen saturation of >90% All effort should be made to prevent hypoxia, hypercapnea, and respiratory acidosis as they have deleterious effects in patients with brain disease The use of positive end expiratory pressure (PEEP) Positive pressure ventilation in general increases functional residual capacity, prevents alveolar de-recruitment, and improves oxygenation It is very useful in cases where pulmonary abnormalities contribute to the respiratory insufficiency However, PEEP may increase ICP in selected clinical circumstances First, the positive pressure could be transmitted directly through the neck to Downloaded from Cambridge Books Online by IP 216.195.11.197 on Thu Nov 05 23:26:57 GMT 2015 http://dx.doi.org/10.1017/CBO9780511659096.027 Cambridge Books Online © Cambridge University Press, 2015 291 292 Chapter 21b: Respiratory care of the ICH patient the cranial cavity Second the rise in the intrathoracic pressure causes decreased venous return to the heart and, as a result, the jugular venous pressure rises, leading to higher cerebral blood volume (CBV) and an increase in ICP Third, the reduction in venous return causes decreased cardiac output and blood pressure with net effect of reduction of cerebral perfusion pressure The brain reacts to this low CPP by vasodilation which will increase the overall CBV and potentially exacerbate the increase in ICP When these theoretical risks were translated to clinical trials, the danger of PEEP to ICP was much less obvious The effect is not seen in lungs with poor compliance [35], it is clinically insignificant in patients with intact or partially intact autoregulation [36,37] and, in general, the preponderance of available studies suggest that a deleterious effect on ICP or CPP is quantitatively modest or non-existent, with levels of PEEP up to 15 cmH2O) [38–41] The use of protective mechanical ventilation Brain directed ventilation strategies implemented the use of large tidal volumes, high-inspired oxygen, low PEEP, intravascular fluid loading, and use of vasopressors to maintain adequate CPP All of these measures were used to ensure protection of the airways with proper oxygenation, maintenance of adequate levels of CO2, and prevention of deleterious effects of positive pressure ventilation on ICP On the other hand, in the presence of severe lung disease, lung protective MV would mean the use of low tidal volume and plateau pressure to prevent alveolar overdistension, the use of PEEP to prevent atelectasis, and restricted fluid use to aid in oxygenation and to prevent ventilation-induced lung injury (VILI), which is histologically similar to the alveolar damage associated with ARDS/ALI syndromes (adult respiratory distress syndrome and acute lung injury) Not only can VILI contribute to the development of ARDS/ALI in highrisk patients, it also affects the overall morbidity and mortality in those individuals [42] We not know yet what are the implications and importance of VILI in patients with neurological diseases Theoretically, the use of low tidal volume may lead to reduction in minute ventilation and hypercapnea, and this may lead to an increase in ICP We have some preliminary data indicating that low tidal volume use is safe in patients with neurological injury and should be used if the patient’s medical condition warrants it [43] Use of other specialized methods of ventilation Most patients with a hemorrhagic stroke will have normal or only moderately abnormal lungs, and therefore conventional modes of ventilation will be more than adequate In the patient with severely damaged lungs, with ARDS or pulmonary fibrosis, conventional methods of ventilation may be ineffective The use of high-frequency oscillating ventilation (HFOV), prone position, and nitric oxide may help oxygenation, but their effect on ICP and CBF are not well studied They would not be used unless the respiratory condition demands it When to wean from mechanical ventilation It is very clear that prolonged mechanical ventilation leads to an increase in mortality, morbidity, and ICU length of stay [44] In order to expedite the weaning process, a number of variables were studied in order to determine which could predict successful weaning from the ventilator Ideally, there should be several parameters that could predict, accurately and with a high success rate, which patient could be weaned successfully The American College of Chest Physicians and the American Association for Respiratory Care advocate the use of eight different parameters to enhance accuracy of successful weaning [45] Even with rigorous application of those parameters, 13% of patients with parameters indicating success will still fail extubation The parameters recommended by the American College of Chest Physicians were elaborated using patients intubated for respiratory distress due to pulmonary abnormalities Downloaded from Cambridge Books Online by IP 216.195.11.197 on Thu Nov 05 23:26:57 GMT 2015 http://dx.doi.org/10.1017/CBO9780511659096.027 Cambridge Books Online © Cambridge University Press, 2015 Chapter 21b: Respiratory care of the ICH patient Patients intubated for reasons related to abnormalities of the central nervous system are not represented, and so these parameters will be even less accurate in the patient with ICH In neurologically impaired patients such as stroke, fewer parameters need to be considered The GCS is likely the best predictor of successful extubation In a randomized study, Namen and colleagues found that successful extubation rose by 39% for each 1-point increment in the GCS and that a GCS of or more is associated with the best success [46] Coplin and collaborators [47], however, found that GCS is not a major factor in predicting extubation Their study showed that 80% of patients with GCS of could be extubated, and patients with GCS of had an even higher rate of extubation success (90%) It makes sense that level of consciousness (LOC) should be an important factor in successful extubation, but clearly more studies are needed Besides LOC, it is also important to be sure that pharyngeal muscles are strong enough to protect the airway Clinical evaluation of facial, pharyngeal muscles and neck flexion are an excellent gauge of airway protection If respiratory muscle weakness is the reason for intubation, the predictors used by pneumologists can be of some value although the studies did not include patients with neuromuscular disease (44) Parameters predicting successful extubation in the studies mentioned include: SaO2 of >90% on FiO2 140), stable blood pressure (systolic BP of 90–160 mmHg), no overt tachypnea, and no hypoxia Parameters of extubation mentioned above have been met Application of spontaneous breathing trial (SBT): three options exist to perform the SBT: 1) T-tube trial 2) low-level pressure support ventilation (PSV), and 3) use of Automatic Tube Compensation (ATC) In pulmonary patients, there is no difference in the percentage of patients who pass the SBT or in those who will be extubated if either method was used [48] In our patient population, the traditional spontaneous breathing trial is not reliable If the problem was one of LOC, an awake patient who triggers the ventilator on a regular basis, coughs well, and defends his airway can be extubated without further ado If the problem is weakness of the cranial nerves innervating the pharynx, the patient will breathe easily without the ventilator, but extubation cannot occur as long as the weakness persists For the patient with neuromuscular weakness, fatigue can occur several hours after the ventilator’s assistance has been removed The patient will well on a SBT of hours, seem fine and then go into respiratory failure during the night For these patients, pressure support must be gradually brought to hours, and then they need to successfully remain at this level for 24 hours Only then are they ready for extubation, again presuming that the bulbar muscles are strong Trial of extubation Many studies demonstrated that 13% of those who pass the SBT and got extubated will fail and be intubated again This number increases up to 40% if SBT is not done prior to extubation attempt Physicians should always look for possible reversible causes of failure and correct them in order to succeed with the next trial After Downloaded from Cambridge Books Online by IP 216.195.11.197 on Thu Nov 05 23:26:57 GMT 2015 http://dx.doi.org/10.1017/CBO9780511659096.027 Cambridge Books Online © Cambridge University Press, 2015 293 294 Chapter 21b: Respiratory care of the ICH patient Table 21b.1 Preparation −10 Rapid assessment of the patient Collect drugs and equipment needed Be ready for possible complications of the procedure (e.g hypotension) Pre-oxygenation −5 Induction/ Premedication −2 paralysis time zero Oxygenate 100% with nonbreather/bag valve mask Think of the LOAD: Lidocaine Opiate Atropine Defasciculating dose of non-depolarizing paralytic agent stabilization of the patient, another trial of SBT can be attempted by applying the same principles and parameters each time Tracheostomy: indications and timing Long-term outcome in intensive care unit survivors after mechanical ventilation for intracerebral hemorrhage is better than that for ischemic stroke In a retrospective study of 120 ventilated patients, survival was 57% at years, and 42% of these had slight or no disability Factors correlating with unfavorable outcome were age > 65 years and a GCS below 15 at discharge [49] In a similar retrospective study, early tracheostomy correlated with shorter ICU and hospital stays (p