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(BQ) Part 1 book Clinical application of mechanical ventilation presents the following contents: Principles of mechanical ventilation, effects of positive pressure ventilation, classification of mechanical ventilators, operating modes of mechanical ventilation, special airways for ventilation,...
Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it David W Chang Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it This is an electronic version of the print textbook Due to electronic rights restrictions, some third party content may be suppressed Editorial review has deemed that any suppressed content does not materially affect the overall learning experience The publisher reserves the right to remove content from this title at any time if subsequent rights restrictions require it For valuable information on pricing, previous editions, changes to current editions, and alternate formats, please visit www.cengage.com/highered to search by ISBN#, author, title, or keyword for materials in your areas of interest Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it David W Chang, Ed.D., RRT–NPS Professor Department of Cardiorespiratory Care University of South Alabama Mobile, Alabama Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Clinical Application of Mechanical Ventilation, Fourth Edition David W Chang Vice President, Careers & Computing: Dave Garza Publisher, Health Care: Stephen Helba Associate Acquisitions Editor: Christina Gifford Director, Development–Careers & Computing: Marah Bellegarde Product Development Manager, Careers: Juliet Steiner Associate Product Manager: Meghan E Orvis Editorial Assistant: Cassie Cloutier © 2014, 2006, 2001, 1997 Delmar, Cengage Learning ALL RIGHTS RESERVED No part of this work covered by the copyright herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical, including but not limited to photocopying, recording, scanning, digitizing, taping, Web distribution, information networks, or information storage and retrieval systems, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without the prior written permission of the publisher For product information and technology assistance, contact us at Cengage Learning Customer & Sales Support, 1-800-354-9706 For permission to use material from this text or product, submit all requests online at www.cengage.com/permissions Further permissions questions can be e-mailed to permissionrequest@cengage.com Executive Brand Manager: Wendy Mapstone Market Development Manager: Jonathan Sheehan Senior Production Director: Wendy Troeger Production Manager: Andrew Crouth Senior Content Project Manager: Kara A DiCaterino Senior Art Director: David Arsenault Cover Image: © Icons Jewelry/www.shutterstock.com © Sebastian Kaulitzki/www.shutterstock.com Library of Congress Control Number: 2012953799 ISBN-13: 978-1-1115-3958-0 ISBN-10: 1-1115-3958-8 Delmar Maxwell Drive Clifton Park, NY 12065-2919 USA Cengage Learning is a leading provider of customized learning solutions with office locations around the globe, including Singapore, the United Kingdom, Australia, Mexico, Brazil, and Japan Locate your local office at: international.cengage.com/region Cengage Learning products are represented in Canada by Nelson Education, Ltd To learn more about Delmar, visit www.cengage.com/delmar Purchase any of our products at your local college store or at our preferred online store www.cengagebrain.com Notice to the Reader Publisher does not warrant or guarantee any of the products 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part, from the readers’ use of, or reliance upon, this material Printed in the United States of America 17 16 15 14 13 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Dedicated with love to my wife, Bonnie and our children, Michelle, Jennifer, and Michael for their support in my professional endeavors and personal leisure activities Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Contents Preface Acknowledgments xxvi xxx Chapter 1: Principles of Mechanical Ventilation Introduction Airway Resistance Factors Affecting Airway Resistance Airway Resistance and the Work of Breathing (∆P) Effects on Ventilation and Oxygenation Airflow Resistance Lung Compliance Compliance Measurement Static and Dynamic Compliance Compliance and the Work of Breathing Effects on Ventilation and Oxygenation Deadspace Ventilation Anatomic Deadspace Alveolar Deadspace Physiologic Deadspace Ventilatory Failure Hypoventilation Ventilation/Perfusion (V/Q) Mismatch Intrapulmonary Shunting Diffusion Defect Oxygenation Failure Hypoxemia and Hypoxia Clinical Conditions Leading to Mechancial Ventilation Depressed Respiratory Drive Excessive Ventilatory Workload Failure of Ventilatory Pump 3 5 6 10 10 10 11 11 11 12 12 13 14 15 16 17 18 18 18 19 VII Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it VIII Contents Summary Self-Assessment Questions Answers to Self-Assessment Questions References Additional Resources 21 21 24 24 25 Chapter 2: Effects of Positive Pressure Ventilation Introduction Pulmonary Considerations Spontaneous Breathing Positive Pressure Ventilation Airway Pressures Compliance Cardiovascular Considerations Mean Airway Pressure and Cardiac Output Decrease in Cardiac Output and O2 Delivery Blood Pressure Changes Pulmonary Blood Flow and Thoracic Pump Mechanism Hemodynamic Considerations Positive Pressure Ventilation Positive End-Expiratory Pressure Renal Considerations Renal Perfusion Indicators of Renal Failure Effects of Renal Failure on Drug Clearance Hepatic Considerations PEEP and Hepatic Perfusion Indicators of Liver Dysfunction Effects of Decreased Hepatic Perfusion on Drug Clearance Abdominal Considerations Effects of PEEP and Increased Intra-Abdominal Pressure Gastrointestinal Considerations Nutritional Considerations Muscle Fatigue Diaphragmatic Dysfunction Nutritional Support Nutrition and the Work of Breathing Neurologic Considerations Hyperventilation Ventilatory and Oxygenation Failure Indicators of Neurologic Impairment Summary Self-Assessment Questions Answers to Self-Assessment Questions References 27 28 28 28 29 30 30 30 31 31 32 34 34 34 35 35 36 36 38 38 38 38 39 39 40 40 41 41 41 42 43 43 44 44 45 45 48 48 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 358 Chapter 11 Circuit Leaks (Figure 11-36) Arrow b shows that the air leak (less volume) lowers the PIP—the pressure required for volume delivery P (cm H2O) V (L/m) V (L) (Figure 11-37) When a circuit leak occurs in the presence of PEEP, the circuit pressure may drop to or below the preset sensitivity level (dashed lines) This causes autotriggering and rapid mechanical breaths Volume waveforms are primarily used to ensure accurate V T delivery They can also be used to check for air leak (Figure 11-36) In the second volume waveform, letter a (arrow) demonstrates that a leak has developed, since the volume never returns to the zero baseline The ventilator still delivers the same flow pattern, but the pressure waveform (b) shows that the PIP for ventilation has been reduced, since less volume is being delivered to the patient’s lungs Also note that the expiratory flow waves have decreased volumes expired after the leak develops The third pressure-time waveform (c) is used to emphasize that the negative pressure to trigger the sensitivity threshold may appear the same (although sometimes the descent to the sensitivity threshold may be prolonged), but because negative pressure in the circuit is dependent on gas decompression, it will be more difficult for the patient to reduce pressure to the sensitivity threshold if gas can be drawn from the atmosphere Figure 11-37 demonstrates the same leak problem as presented in Figure 11-36 However, in this example, approximately 10 cm H2O PEEP has been added to the circuit and patient’s lungs Again, volume does not return to zero The PIPs and expiratory flow patterns have also been reduced for the waveforms depicted after the leak appeared The arrow indicates that once the leak begins, pressure in the circuit starts dropping to the sensitivity setting below the PEEP level set (dashed lines) 0.8 a 10 12 10 12 60 40 b c Time (sec) 10 12 © Cengage Learning 2014 (Figure 11-36) Arrow a shows air leak since the expiratory volume is less than the inspired tidal volume Figure 11-36 Changes to the volume-, flow-, and pressure-time waveforms demonstrate the development of an air leak Note that the expiratory volume starting from the second breath (a) does not return to baseline The peak inspiratory pressure starting from the second breath (b) is reduced from the previous level Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 359 0.8 10 12 10 12 Time (sec) 10 12 60 40 © Cengage Learning 2014 P (cm H2O) V (L/m) V (L) Ventilator Waveform Analysis Figure 11-37 Changes to the volume-, flow-, and pressure-time waveforms demonstrate the effect of an air leak when PEEP is used A reduced circuit pressure (due to air leak) is sufficient to drop the sensitivity level below the PEEP level, causing autotriggering and fast mechanical frequency This may lead to autotriggering and go unnoticed unless respiratory frequencies reach extremely high levels (.25 to 30/min) PRESSURE-VOLUME LOOP (PVL) AND FLOW-VOLUME LOOP (FVL) Pressure-Volume Loop (PVL) (Figure 11-38) The double-headed arrow shows the flow-resistive pressure or transairway pressure (PTA) PTA PAO PALV throughout the pressure-volume loop [Note: end-inspiratory PAO PIP, end-inspiratory PALV peak PALV or plateau pressure Refer to Figure 11-4 for review.] Another option offered by graphics software is the pressure-volume loop (PVL) presented in Figure 11-38 for an assist breath during constant flow ventilation The PAO can be read from the x-axis and volume from the y-axis The doubleheaded arrow indicates that the flow-resistive pressure (P TA) is the difference between PAO and PALV (dashed line) P TA remains the same throughout inspiration, as it does for the step ascending ramp pressure waveform once the initial peak flow is reached and maintained during constant flow ventilation The PIP of 30 cm H 2O (dashed line) and peak PALV of 25 cm H 2O are labeled It is assumed that the CLT is unchanged in this example since PALV rises linearly with increase in volume Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 360 Chapter 11 800 PIP Peak PALV Volume (mL) 600 400 PAO PTA 10 20 25 30 40 Pressure (cm H2O) Assist Breath 50 60 © Cengage Learning 2014 200 Figure 11-38 Characteristics of a pressure-volume loop The dotted line within the loop is the peak alveolar pressure (PALV or plateau pressure) The transairway pressure (PTA or flow resistive pressure) is the difference between the PAO and PALV (Figure 11-38) This pressure-volume loop shows that the lung-thorax compliance (CLT) remains unchanged because the PALV rises linearly with increases in volume Effects of Lung-Thorax Compliance on PVL Figure 11-39 shows a control breath; there is no negative pressure to trigger the mechanical breath This PVL illustrates how a reduction in CLT causes the loop to move down and to the right (i.e., toward the pressure axis) The increase in (2 ) 2) P PI AL V( P (1 ) PI P P AL V( 1) 800 Volume (mL) 600 PTA 400 PTA 10 20 30 40 Pressure (cm H2O) 50 60 © Cengage Learning 2014 200 Figure 11-39 The effects of lung-thorax compliance (CLT ) on the pressure-volume loop during volume-controlled, constant flow ventilation A decreased CLT shifts the curve toward the pressure axis Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 361 Ventilator Waveform Analysis (Figure 11-39) A decrease in CLT causes the pressurevolume loop to shift toward the pressure axis (Figure 11-39) A decrease in CLT will not affect the PTA because the PIP- PALV gradient (PTA) remains unchanged (Figure 11-40) In situations where the airflow resistance is increased, the PALV remains unchanged while PTA, PIP, and PAO are increased (Figure 11-41) The pressure-volume (compliance) loop shows that the initial point of inflection (Ipi) is the compliance point in which the alveoli are recruited (opened) during mechanical ventilation PIP (from 30 to 40 cm H2O) is proportionate to the increase in PALV (from 25 to 35 cm H2O) that is caused by the reduction in CLT The PTA gradient throughout inspiration (and between PIP and peak PALV ) is held constant PTA is affected by changes in resistance, not by the changes in CLT It is essential to note that on some ventilators (e.g., Servo 300), pressure and volume may be assigned to the y- and x-axis, respectively A reduction in CLT would shift the PVL up and to the left (i.e., toward the pressure axis). Effect of Airflow Resistance on PVL Figure 11-40 shows how the PVL is affected by an increase in resistance (double-headed arrows and dashed lines) PALV remains unchanged in this example, while inspiratory and expiratory flow-resistive pressure (PTA), PIP, and PAO have all increased. Lower Inflection Point on PVL and Titration of PEEP Figure 11-41 shows the effects on the PVL if CLT changes during tidal volume delivery and is presented here only as a point of reference The dashed line indicates that the slope of the PALV during V T delivery has changed Historically, 800 PALV PIP(1) PIP(2) PA0 400 PTA(2) 200 PTA(1) 10 20 30 Pressure (cm H2O) 40 50 © Cengage Learning 2014 Volume (mL) 600 Figure 11-40 The effects of airflow resistance on the pressure-volume loop during volumecontrolled, constant flow ventilation An increased airflow resistance causes increase in PIP, inspiratory and expiratory PTA, and PAO Note that the PALV is unchanged Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 362 Chapter 11 800 400 200 Initial Point of Inflection PEEP 10 30 40 50 60 Pressure (cm H2O) Figure 11-41 The initial point of inflection (Ipi) shows the change in the slope from low to improved compliance A level of PEEP slightly higher (e.g., cm H2O) than the Ipi may be used to prevent alveolar closure during expiration (Figure 11-41) In the presence of Ipi on the pressure-volume loop, PEEP may be added at or slightly above the Ipi to prevent alveoli collapse during expiration 20 © Cengage Learning 2014 Volume (mL) 600 it was thought that a line could be drawn through the initial slope caused by low CLT, and compared to the line for the slope caused by an improvement in CLT For lungs with homogenous characteristics (non-ARDS), the change in slope from low to improved compliance is known as the initial point of inflection (Ipi) (Beydon et al., 1991) The Ipi was thought to occur when alveoli were recruited (opened) by volume pressure during inspiration In this example, PALV could have been measured by adding progressively larger volumes of gas (beginning at approximately 35 mL) to the patient’s lung via a large-volume syringe until the V T was reached, and then plotting the pause pressures acquired In the presence of Ipi, some studies suggested that PEEP could be added slightly above (2 cm H 2O) the inflection point to prevent the alveoli from closing during expiration However, other studies suggest setting PEEP above the closing PALV pressure on the expiratory side of the curve, to prevent alveolar collapse during mechanical ventilation Further research has disputed the presence and/ or clarity of inflection points being used to set PEEP and usefulness of this strategy in ventilator-patient management Studies suggest that the repeated opening and closing of alveoli during mechanical ventilation causes shearing of lung parenchyma (barotraumas), which may promote development of ALI, ARDS, and multiple organ failure The Ipi does not apply to lungs with nonhomogenous characteristics (i.e., ALI and ARDS) In ARDS, different lung units have different compliance and opening pressure requirements For a related discussion, review the sections on ALI, ARDS and recruitment maneuver in Chapter 15 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 363 Ventilator Waveform Analysis 800 Volume (mL) 600 Point of Upper Inflection 400 PALV 10 20 30 40 50 Pressure (cm H2O) 60 © Cengage Learning 2014 200 Figure 11-42 The point of upper inflection (Ipu) shows a reducing lung-thorax compliance due to hyperdistention of the alveoli The tidal volume may be reduced until the Ipu (or duckbill) disappears Upper Inflection Point on PVL and Adjustment of VT (Figure 11-42) In the presence of Ipu on the pressure-volume loop, the tidal volume should be reduced until the Ipu (duckbill) disappears (Figure 11-43) On a flowvolume loop, the inspiratory flow is above the horizontal axis, whereas the expiratory flow is below (Figure 11-43) Positive response to bronchodilator therapy improves the expiratory flow as airflow resistance is reduced Inspiratory flow is unchanged because it is determined by the settings on the ventilator Figure 11-42 presents a PVL where an upper inflection point (Ipu) existed according to early research on this subject In this example, the PALV has been plotted as described for Figure 11-37 CLT changed later during V T delivery because of hyperdistention of the alveoli The reduction in CLT late in the inspiratory cycle was called the Ipu (Dambrosio et al., 1997) In this example, slope for PALV (dashed line) is normal, and slope (dashed line) shows a decrease in CLT and the point of upper inflection The appearance of the upper shape of the PAO curve indicating the presence of an Ipu was known as the duckbill PVL When a duckbill occurred, the V T could be reduced until the duckbill vanished (Roupe et al., 1995) Presently, like the Ipi, research is not supporting clear or accurate indications of the Ipu, and it, too, is presented only as a historical reference to issues related to ventilator-patient management of ARDS patients that are in contention and need further study Effects of Airway Status on Flow-Volume Loop (FVL) Figure 11-43 shows another waveform option, the flow-volume loop (FVL) FVLs show flow measurements on the y-axis, and volume measurement on the x-axis Inspiratory flow is above the x-axis and expiratory flow is below This example shows two superimposed waveforms during constant flow ventilation at 40 L/min and results of pre- and postbronchodilator therapy Following bronchodilator therapy, airflow resistance is typically reduced (Garner, 2002) Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 364 Chapter 11 60 40 · V (L/min) 20 100 200 300 400 Volume (mL) 500 600 700 240 260 Resistance Reduced © Cengage Learning 2014 220 Figure 11-43 The effect of airflow resistance on the flow-volume loop A reduction in airflow resistance increases the peak expiratory flow rate SUMMARY In summary, if graphics of flow-, volume- and pressure-time waveforms, pressurevolume loop, and flow-volume loop could be saved when patients were first placed on a ventilator, ventilator management of patient’s progress could be studied and greatly enhanced Follow-up graphics could be saved and superimposed over the initial copies for comparison, similar to what has been done with the figures throughout this chapter This can now be done on a minimal level on some ventilator graphics packages Disk files or printed copies of therapeutic interventions (i.e., bronchodilators, changes in mode of ventilation, chest physical therapy, etc.) and improvements could be documented Graphic analysis could be used to facilitate discussion and be shared with colleagues and physicians Outcome assessments of the performance of therapists and respiratory care departments in the area of ventilator management could be documented A higher quality of ventilator-patient assessment and care is being carried out by practitioners with sufficient expertise in graphics analysis on a day-to-day basis The sophisticated level of software needed for documentation of these improvements in practice, however, is not readily available There have been some improvements, but many more are needed to collect and analyze patient clinical status via ventilator waveforms The technology is available, and it will be exciting to see the eventual changes as the professionals demand further improvements from the ventilator manufacturers Expertise in waveform analysis at a high level is not required Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Ventilator Waveform Analysis 365 for professionals in respiratory care as yet, and the level of expertise is unknown Those with knowledge and experience know that waveform analysis improves patient care and that it is a very useful tool in ventilator management However, these improvements need to be studied and supported through research There is still much to learn Hopefully the knowledge you gain through study of this work will help serve that purpose Self-Assessment Questions The ascending ramp and sine flow waveforms are not used for positive pressure ventilation because the initial flow rate is _ for most patients These two waveforms may be appropriate for _ ventilation A too high, control C not sufficient, control B too high, intermittent mandatory D not sufficient, intermittent mandatory In volume, pressure and flow waveforms, time in seconds is displayed along the _ axis A x- or horizontal B x- or vertical C y- or horizontal D y- or vertical Tidal volume can be calculated or determined by measuring the _ under a _ waveform A slope, flow/time B slope, pressure/time C area, flow/time D area, pressure/time The area enclosed under the expiratory flow waveform should _ the area under the inspiratory flow waveform If the expiratory volume is less than the inspiratory volume, _ may be present A be greater than, airflow obstruction B be equal to, airflow obstruction C be greater than, circuit leak or gas trapping D be equal to, circuit leak or gas trapping In assist/control mode, the I:E ratio is variable because the _ time of a breath is dependent on the beginning of the _ breath A inspiratory, preceding B inspiratory, following C expiratory, preceding D expiratory, following On a pressure waveform, PEEP is present when the end-expiratory pressure rests: A at cm H2O B below cm H2O C above cm H2O D above cm H2O Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 366 Chapter 11 On the pressure waveform, assist effort is present when the trigger pressure reaches the _ setting A tidal volume B sensitivity C pressure limit D peak flow In CPAP mode, there are no _ breaths and the airway pressure is above _ cm H2O A mechanical, B mechanical, C spontaneous, D spontaneous, An increase in inspiratory flow or airflow resistance would show an unchanged _ but increased _ (See Figure 11-11.) A PALV, PIP and PTA B PALV and PIP, PTA C PTA and PALV, PIP D PALV, PTA 10 A decrease in total compliance (CLT) would show an unchanged _ but increased _ (See Figure 11-12.) A PALV, PIP and PTA B PTA, PIP and PALV C PIP, PALV and PIP D PALV, PTA 11 When the flow waveform selection is changed from constant flow to true descending ramp while holding inspiratory time constant, the same volume can only be maintained if the peak flow of the descending pattern is: A increased B decreased C halved D doubled 12 When the flow waveform selection is changed from constant flow to true descending ramp during VCV, the same volume can only be maintained if the inspiratory time of the descending pattern is: A increased B decreased C halved D doubled 13 With time-limited ventilation, the higher initial peak flow for the descending ramp flow wave creates a _ initial flow resistive pressure (PTA) than the PTA created by the constant flow (See Figure 11-14.) A higher B lower C similar D constant 14 With flow-limited ventilation, the initial flow-resistive pressure (PTA) is the same for the _ flow waves The initial peak flow level stays the same for _ flow during flow-limited ventilation (See Figure 11-14.) A constant, constant B constant, descending ramp C descending ramp, descending ramp D constant and descending ramp, constant and descending ramp Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Ventilator Waveform Analysis 367 15 In constant flow and descending ramp flow ventilation, the rise in alveolar pressure (PALV) is directly related to _ and inversely related to _ A compliance, volume delivery B compliance, airflow resistance C volume delivery, compliance D volume delivery, airflow resistance 16 At constant TI, a decreased flow leads to (See Figure 11-15): A higher VT and PALV B higher VT, PTA, and PALV C lower PTA and PALV D lower VT, PTA, and PALV 17 During descending ramp flow ventilation, a higher end-flow leads to a _ VT and PTA and it _ affect the PALV (See Figure 11-16.) A larger, does B larger, does not C smaller, does D smaller, does not 18 When peak flow is constant (square), _ are _ related A VT and PALV; directly B VT, TI and PALV; directly C VT and PALV; inversely D VT, TI and PALV; inversely 19 In pressure-controlled ventilation, _ are typically set by the operator A rate and I:E ratio B pressure level and I:E ratio C pressure level and rate D pressure level, rate, and I:E ratio 20 In pressure-controlled ventilation, the flow level and VT delivered are primarily dependent on the: A tidal volume B tidal volume and lung characteristics C pressure level set and patient effort D pressure level set and lung characteristics 21 During inverse ratio pressure-controlled ventilation, the patients are usually sedated and paralyzed in order to prevent: A barotrauma C hyperventilation B dyssynchrony with the ventilator D hypoxia 22 In pressure support ventilation, only the _ level is set and under normal condition, _ are primarily under the patient’s control A pressure support; flow, volume, and inspiratory time B tidal volume; flow, volume, and inspiratory time C PEEP; flow and volume D plateau pressure; inspiratory time and volume Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 368 Chapter 11 23 During pressure-controlled ventilation, a(n) _ airflow resistance or _ compliance would reduce the delivered flow and tidal volume A increased, increased B increased, decreased C decreased, increased D decreased, decreased 24 Tachypnea, agitation, accessory muscle use, active expiration, muscle fatigue, and respiratory failure are signs of: A patient-ventilator dyssynchrony B hyperventilation C anxiety D decreased metabolic rate 25 On a flow waveform, failure of the expiratory flow to return to baseline is indicative of _ and this condition may lead to _ and possibly auto-PEEP A incomplete inspiration, gas trapping B incomplete inspiration, hypoventilation C incomplete expiration, gas trapping D incomplete expiration, hypoventilation 26 In the presence of excessive airway resistance, the expiratory flow is _ and the expiratory time is _ A increased, prolonged B increased, shortened C decreased, prolonged D decreased, shortened 27 A decreased CLT leads to a higher expiratory peak flow, a _ PIP, and a _ expiratory time A higher, longer B higher, shorter C lower, longer D lower, shorter 28 A delay of positive pressure waveform (i.e., lack of ventilator response) in spite of a normal negative pressure waveform (i.e., good patient effort) is indicative of: A inadequate line pressure B ventilator malfunction C dysfunction of the inspiratory valve or sensitivity setting D electrical malfunction 29 Failure of the expiratory flow to return to the zero baseline is indicative of: A gas leak or air trapping B airflow obstruction C power failure D high lung compliance 30 When a circuit leak occurs in the presence of PEEP, pressure in the circuit drops to the sensitivity setting below the PEEP level and _ develops and leads to extremely _ mechanical breaths A auto-PEEP, slow B auto-PEEP, fast C autotriggering, slow D autotriggering, fast Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Ventilator Waveform Analysis 369 31 The difference between PAO and PALV is: (See Figure 11-38.) A PIP B PTA C PEEP D CLT 32 On a volume-pressure curve, the _ is assumed to be stable and unchanged if PALV rises linearly with increases in volume (See Figure 11-38.) A CLT B PIP C PTA D PEEP 33 On a pressure-volume loop, a reduction in CLT causes the loop to move toward the (See Figure 11-39): A y axis B volume axis C pressure axis D A and B only 34 On a pressure-volume loop, a reduction in CLT will not change the PTA because the gradient between _ remains the same (See Figure 11-39.) A PTA and PAO B PAO and PALV C PIP and PAO D PIP and PALV 35 On a pressure-volume loop, an increase in resistance would not affect the _ while the _ are increased (See Figure 11-40.) A PALV; PTA and PIP B PALV; PTA, PIP, and PAO C PTA; PIP and PAO D PTA; PAO, PIP, and PALV 36 The initial point of inflection (Ipi) occurs when alveoli are recruited during _ In the presence of Ipi, _ can be added slightly above the pressure at the inflection point to prevent the alveoli from closing during expiration (See Figure 11-41.) A inspiration, PEEP B expiration, PEEP C inspiration, tidal volume D expiration, tidal volume 37 Overinflation of the alveoli causes a(n) _ in CLT leading to the appearance of an upper inflection point (Ipu) The Ipu can be minimized by reducing the _ (See Figure 11-42.) A increase, PEEP B increase, tidal volume C decrease, PEEP D decrease, tidal volume 38 On a flow-volume loop, the expiratory flow is _ the horizontal (volume) axis and it is usually _ following a successful bronchodilator therapy (See Figure 11-43.) A above, increased B above, decreased C below, increased D below, decreased Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 370 Chapter 11 Answers to Self-Assessment Questions C 11 D 21 B 31 B A 12 D 22 A 32 A C 13 A 23 B 33 C D 14 D 24 A 34 D D 15 C 25 C 35 B C 16 D 26 C 36 A B 17 B 27 B 37 D A 18 B 28 C 38 C A 19 D 29 A 10 B 20 D 30 D References Acute Respiratory Distress Syndrome Clinical Network (ARDSNet) (2000) Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome New England Journal of Medicine, 342, 1301–1308 Beydon, L., Lemaire, F., & Jonson, B (1991) Lung mechanics in ARDS: Compliance and pressure-volume curves In Aapol, W M., & Lemaire, F (eds.) Adult respiratory distress syndrome (pp 139–161) New York, NY: Marcel Dekker Chatburn, R L (2001) A new system for understanding modes of mechanical ventilators Respiratory Care, 46(6), 604–621 Chatburn, R L (2007) Classification of ventilator modes: Update and proposal for implementation, Respiratory Care, 52(3), 301– 323 Dambrosio, M., Roupie, E., Mollet, J J., Anglade, M C., Vasile, N., Lemarie, F., & Brochard, L (1997) Effects of positive end-expiratory pressure and different tidal volumes on alveolar recruitment and hyperinflation Anesthesiology, 87(3), 495–503 Dennison, F H., Taft, A A., Mishoe, S C., Hooker, L L., Eatherly, S B., & Beckham, R W (1989) Analysis of resistance to gas flow in nine adult ventilator circuits CHEST Journal, 96, 1374–1379 Dick, C R., & Sassoon, C S H., (1996) Patient-ventilator interactions Clinics in Chest Medicine, 17(3), 423–438 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it Ventilator Waveform Analysis 371 Garner, S S., Wiest, D B., Bradley, J W., & Habib, D M (2002) Two administration methods for inhaled salbutamol in intubated patients Archives of Disease in Childhood, 87, 49–53. MacIntyre, N R., & Branson, R D (2008) Mechanical ventilation 2nd ed Philadelphia, PA: W B Saunders Co Marini, J J., Capps, J S., & Culver, B H (1985) The inspiratory work of breathing during assisted mechanical ventilation CHEST Journal, 87(5), 612–618 Marini, J J., Rodriguez, R M., & Lamb, V (1986) Bedside estimation of the inspiratory work of breathing during mechanical ventilation CHEST Journal, 89(1), 56–63 Messinger, G., Banner, M J., Blanch, P B & Layon, A J (1995) Using tracheal pressure to trigger the ventilator and control airway pressure during continuous positive airway pressure decreases work of breathing CHEST Journal, 108, 509–514 Nilsestuen, J O., & Hargett, K (1996) Managing the patient-ventilator system using graphic analysis: An overview and introduction to graphics corner Respiratory Care, 41(12), 1105–1120 Roupe, E., Dambrosio, M., Servillo, G., Mentec, H., el Atrous, S., Beydon, L., … Brochard, L (1995) Titration of tidal volume and induced hypercapnia in acute respiratory distress syndrome American Journal of Respiratory Critical Care, 152, 121–128 Tobin, M J (1994) Principles and practice of mechanical ventilation New York, NY: McGraw-Hill Tobin, M J., Perez, W., Guenther, S M., Semmes, B J., Mador, M J., Allen, S J., … Dantzker, D R (1986) The pattern of breathing during successful and unsuccessful trials of weaning from mechanical ventilation American Review of Respiratory Disease, 134, 1111–1118 Additional Resources Modes of ventilation Mireles-Cabodevila, E., Diaz-Guzman, E., Heresi, G A., & Chatburn, R L (2009) Alternative modes of mechanical ventilation: A review for the hospitalist Cleveland Clinic Journal of Medicine, 76(7), 417–430 Volume-controlled and pressure-controlled ventilation Burke, W C., Crooke, P S., III, Marcy, T W., Adams, A B., & Marini, J J (1993) Comparison of mathematical and mechanical models of pressure-controlled ventilation Journal of Applied Physiolology, 74(2), 922–933 Cinnella, G., Conti, G., Lofaso, F., Lorino, H., Harf, A., Lemaire, F., & Brochard, L (1996) Effects of assisted ventilation on the work of breathing: Volume-controlled versus pressure-controlled ventilation American Journal of Respiratory Critical Care Medicine, 153(3), 1025–1033 MacIntyre, N R., Gropper, C., & Westfall, T (1994) Combining pressure-limiting and volume-cycling features in a patient-interactive mechanical breath Critical Care Medicine, 22(2), 353–357 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it 372 Chapter 11 Morris, A H., Wallace, C J., Menlove, R L., Clemmer, T P., Orme, J F Jr., Weaver, L K., Dean, N C., … Rasmusson, B (1994) Randomized clinical trial of pressure-controlled inverse ratio ventilation and extracorporeal CO2 removal for adult respiratory distress syndrome American Journal of Respiratory Critical Care Medicine, 149(2), 295–305 Munoz, J., Guerrero, J E., Escalante, J L., Palomino, R., & De La, C B (1993) Pressure-controlled ventilation versus controlled mechanical ventilation with decelerating inspiratory flow Critical Care Medicine, 21(8), 1143–1148 Copyright 2013 Cengage Learning All Rights Reserved May not be copied, scanned, or duplicated, in whole or in part Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s) Editorial review has deemed that any suppressed content does not materially affect the overall learning experience Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it ... Resources XI 10 5 10 6 10 7 10 8 10 8 10 8 10 9 10 9 10 9 11 1 11 2 11 2 11 3 11 3 11 4 11 4 11 5 11 5 11 5 11 6 11 6 11 9 11 9 12 3 Chapter 5: Special Airways For Ventilation Introduction Oropharyngeal Airway Types of Oropharyngeal... Contraindications Safety Requirements 15 1 15 2 15 3 15 4 15 4 15 5 15 5 15 6 15 6 15 7 16 1 16 2 16 2 16 3 16 3 16 3 16 5 16 7 16 8 16 8 16 8 17 1 17 1 17 1 17 2 17 3 17 5 17 7 17 7 17 7 Copyright 2 013 Cengage Learning All Rights... Hypoxia Clinical Conditions Leading to Mechancial Ventilation Depressed Respiratory Drive Excessive Ventilatory Workload Failure of Ventilatory Pump 3 5 6 10 10 10 11 11 11 12 12 13 14 15 16 17 18 18