Eating on Noninvasive Ventilation Hameeda Shaikh, MD Pulmonary and Critical Care Section Edward Hines, Jr. Veterans Affairs Hospital Hines, IL
bolus, shorter swallowing time per bolus, and fewer breaths taken during the period of swallowing. Eurthermore, while on NIV, fewer swallows were followed by inspiration, a condition which may promote prandial aspiration (6, 7). The first eight patients in the study frequently experienced Franco Laghi, MD patient-ventilator uncoupling in the form of swallow-induced Division of Pulmonary and Critical Care Medicine ventilator triggering followed by autotriggering. To limit such Edward Hines, Jr. Veterans Affairs Hospital uncoupling, the remaining seven patients were studied with a Hines, IL; and modified NIV machine that was provided with a patient-conDivision of Pulmonary and Critical Care trolled off-switch pushbutton. As long as the patient pressed Department of Medicine the off-switch pushbutton, the ventilator would stop deliverLoyola University ing assisted breaths—^but not for more than 18 seconds. When Maywood, IL patients used the pushbutton, autotriggering was completely eliminated. Concurrently, 89% of these patients demonstrated a restoration of the normal breathing-swallowing pattern of eeding patients while receiving noninvasive ventilation "exhalation-swallow-exhalation" (6). In contrast, less than 80% (NIV) is a challenge (1). Using the nasogastric tube can of patients displayed this breathing pattern when ventilated with disrupt the patient-mask interface and cause an air leaks the conventional NIV machine and less than 40% of patients (2). Removal of the mask to allow for oral intake may not be when breathing unassisted. The latter percentage is about half of tolerated in patients with respiratory distress. To these conthat previously reported in clinically sable patients with COPD cerns, we must add our limited understanding of the interacinstructed to swallow semisolid food (6). Irrespective of the offtion between breathing and swallowing in critically ill patients switch modification, all patients found swallowing more comand the ever-present concern of inducing aspiration. Accordfortable while on NIV than during unassisted respiration. ingly, many intensivists are reluctant to begin oral nutrition in By what mechanism did swallowing improve on NIV? One patients requiring NIV (3). Withholding nutrition, however, is potential mechanism could be an NIV-induced increase in not without consequence. Malnutrition develops rapidly and is associated with poor outcomes (4). Eurthermore, depriving operating lung volumes (8). Increases in operating lung volumes have been associated with reduced swallow duration and patients of the enjoyment of food detracts from their quality of life. As use of NIV for acute respiratory failure has increased a probable increase in subglottic pressure (8). And greater sub( 1 ), determining how best to provide nutrition to these patients glottic pressures can, in turn, reduce the risk of aspiration (9). Unfortunately, the French investigators (5) did not measure has become a topic of great clinical relevance. In this issue of Critical Care Medicine, Terzi et al (5) lung volumes during the swallowing maneuvers. Nevertheless, it is likely that lung volumes were larger during NIV than durexplore the interaction between nasally delivered NIV and the ing unassisted breathing (10). breathing-swallowing mechanism in 15 patients with chronic A second potential explanation for improved swallowing obstructive pulmonary disease (COPD) when the patients with NIV could be the NIV-induced unloading of the respiwere able to breathe without ventilatory support for at least 2 ratory muscles and the concomitant decrease in carbon dioxhours. All of them were cared for in one ICU during an acute ide tension (10). In healthy subjects, experimentally-induced exacerbation of COPD. The investigators triggered swallowing hypercapnia and elastic loading increase respiratory frequency placing water boluses in the mouth of patients. These boluses and disrupt the normal breathing-swallowing coordinawere given during each of two conditions: unassisted respiration (11, 12). This pattern is similar to what was observed by tion and while on NIV. Compared with unassisted respiration, Terzi et al (5). When their patients were off NIV, there was an all patients demonstrated improved swallowing efficiency increase in arterial carbon dioxide tension and a likely increase while on NIV, with fewer swallows needed to clear the fluid in the mechanical load on the respiratory muscles (10). Similarly to what has been described in healthy subjects (11, 12), the increase in carbon dioxide tension and the likely increase 'See also p. 565. in mechanical load on the respiratory muscles were accompaKey Words: chronic obstructive pulmonary disease; noninvasive ventilation; nutrition; respirafory failure; sv^atlowing nied by a rise in respiratory frequency and a disruption in the Supported, in part, by Veterans Administration Research Service. normal breathing-swallowing coordination. These variables Dr. Shaikh is employed by the Veterans Administration. Dr. Laghi is emimproved during NIV. Could it be the respiratory rate alone is ployed by fhe Veterans Administration/Loyola University. His institution redriving the uncoordinated breathing-swallowing interactions? ceived grant support from fhe Veferans Administration Research Service. This is unlikely for two reasons. Eirst, breathing-swallowing Copyrighf © 2013 by fhe Society of Critical Care Medicine and Lippincoft interactions are preserved during exercise-induced tachypnea Williams & Wilkins (13). Second, even in patients with COPD who are clinically DOI: 10.1097/CCM.0000000000000002
F
Critical Care Medicine
www.ccmjournal.org
737
Editorials
stable, the prevalence of uncoordinated breathing-swallowing interactions is greater than that in healthy subjects (6). The finding of swallow-induced patient-ventilator uncoupling during NIV has been previously described by the French group (14) and is corroborated in the current study (5). Here, the investigators extend theirfindingsby testing an NIV machine connected to a novel patient-controlled off-switch pushbutton. The use of the pushbutton eliminated swallow-induced patientventilator uncoupling. On one hand, this is a predictable result considering that the ventuator would provide no mechanical breaths when the switch was in the off position. On the other hand, the restoration of the normal breathing-swallowing sequence of exhalation-swallow-exhalation is unexpected. This result could be of clinical relevance considering that the postswallow exhalation, which occurs in the vast majority of healthy subjects (8, 11, 12), is thought to prevent aspiration of residual material left in the pharynx after an initial deglutition (6). When the patients studied by Terzi et al (5) were disconnected from NIV, most swallows were followed by inspiration. This postswallow inhalation is similar to what Kijima et al ( 11 ) reported while healthy subjects sustained inspiratory elastic loads. In the latter study (11), postswallow inhalation was associated with coughing, which strongly implies that aspiration occurred as a result of swallowing (11). Despite the high prevalence of postswallow inhalation during unassisted breathing in the French study (5), no patient coughed. Whether this lack of cough resulted from the small volume of the fluid bolus used by the investigators or whether it reflected a low risk for aspiration or the presence of undetected microaspirations remains to be determined. The innovative study by Terzi et al (5) is provocative as it challenges preconceived ideas about the risk of aspiration in patients in respiratory failure. The investigators have set the stage for the study of breathing-swallowing dynamics in patients with acute exacerbations of COPD receiving NIV. The question now is to demonstrate whether oral feeding on NIV— with or without an off-switch pushbutton—is safe and can provide sufficient alimentation in selected patients in respiratory failure. A more fundamental challenge, however, is to demonstrate whether early oral feeding can improve the outcome of these patients—a formidable undertaking considering
738
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the recent report that early initiation of "parenteral" nutrition in critically ill patients is associated with slower recovery and more complications, as compared with late initiation (15). Although these challenges are daunting, it is time to embrace them.
REFERENCES 1. Hill NS: Noninvasive positive-pressure ventilation. In: Principles and Practice of Mechanical Ventilation. Tobin MJ (Ed). New York, McGraw Hill, 2013, pp 447-494 2. Noguchi T, Shiga Y, Koga K, et al; A method to improve a gas leak on mask ventilation in the patient with a nasogastric tube. Anesthesiology 2001 ; 94:545 3. Macht M, Wimbish T, Bodine C, et al; ICU-acquired swallowing disorders. Crit Care Med 2013; 41:2396-2405 4. Artinian V, Krayem H, DiGiovine B: Effects of early enterai feeding on the outcome of critically ill mechanically ventilated medical patients. Chest 2006; 129:960-967 5. Terzi N, Normand H, Dumanowski E, et al: Noninvasive Ventilation and Breathing-Swallowing Interplay in Chronic Obstructive Pulmonary Disease. Crit Care Med 2014; 42:565-573 6. Gross RD, Atwood CW Jr, Ross SB, et al: The coordination of breathing and swallowing in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2009; 179;559-565 7. Nishino T, Hiraga K: Coordination of swallowing and respiration in unconscious subjects. J AppI Rhysiol 1991 ; 70:988-993 8. Gross RD, Atwood CW Jr, Grayhack JP, et al: Lung volume effects on pharyngeal swallowing physiology. J AppI Physiol 2003; 95:2211-2217 9. Logemann JA, Pauloski BR, Colangelo L: Light digital occlusion of the tracheostomy tube: A pilot study of effects on aspiration and biomeohanics of the swallow. Head Neck 1998; 20:52-57 10. Hussain C, Collins EG, Adiguzel N, et al; Contrasting pressure-support ventilation and helium-oxygen during exercise in severe COPD. Respir Med 2011 ; 105:494-505 11. Kijima M, Isono S, Nishino T: Modulation of swallowing reflex by lung volume changes. Am J Respir Crit Care Med 2000; 162:1855-1858 12. Hârdemark Cedborg Al, Sundman E, Boden K, et al: Co-ordination of spontaneous swallowing with respiratory airflow and diaphragmatic and abdominal muscle activity in healthy adult humans. Exp Physiol 2009; 94:459-468 13. Shaker R, Li O, Ren J, et al: Coordination of deglutition and phases of respiration; Effect of aging, tachypnea, bolus volume, and chronic obstructive pulmonary disease. Am J Rhysiol 1992; 263:G750-G755 14. Prigent H, Lejaille M, Terzi N, et al; Effect of a tracheostomy speaking valve on breathing-swallowing interaction. Intensive Care Med 201 2; 38:85-90 15. Casaer MP, Mesotten D, Hermans G, et al: Early versus late parenteral nutrition in critically ill adults. N EngI J Med 2011 ; 365:506-517
March 2014 • Volume 42 • Number 3
Copyright of Critical Care Medicine is the property of Lippincott Williams & Wilkins and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
bolus, shorter swallowing time per bolus, and fewer breaths taken during the period of swallowing. Eurthermore, while on NIV, fewer swallows were followed by inspiration, a condition which may promote prandial aspiration (6, 7). The first eight patients in the study frequently experienced Franco Laghi, MD patient-ventilator uncoupling in the form of swallow-induced Division of Pulmonary and Critical Care Medicine ventilator triggering followed by autotriggering. To limit such Edward Hines, Jr. Veterans Affairs Hospital uncoupling, the remaining seven patients were studied with a Hines, IL; and modified NIV machine that was provided with a patient-conDivision of Pulmonary and Critical Care trolled off-switch pushbutton. As long as the patient pressed Department of Medicine the off-switch pushbutton, the ventilator would stop deliverLoyola University ing assisted breaths—^but not for more than 18 seconds. When Maywood, IL patients used the pushbutton, autotriggering was completely eliminated. Concurrently, 89% of these patients demonstrated a restoration of the normal breathing-swallowing pattern of eeding patients while receiving noninvasive ventilation "exhalation-swallow-exhalation" (6). In contrast, less than 80% (NIV) is a challenge (1). Using the nasogastric tube can of patients displayed this breathing pattern when ventilated with disrupt the patient-mask interface and cause an air leaks the conventional NIV machine and less than 40% of patients (2). Removal of the mask to allow for oral intake may not be when breathing unassisted. The latter percentage is about half of tolerated in patients with respiratory distress. To these conthat previously reported in clinically sable patients with COPD cerns, we must add our limited understanding of the interacinstructed to swallow semisolid food (6). Irrespective of the offtion between breathing and swallowing in critically ill patients switch modification, all patients found swallowing more comand the ever-present concern of inducing aspiration. Accordfortable while on NIV than during unassisted respiration. ingly, many intensivists are reluctant to begin oral nutrition in By what mechanism did swallowing improve on NIV? One patients requiring NIV (3). Withholding nutrition, however, is potential mechanism could be an NIV-induced increase in not without consequence. Malnutrition develops rapidly and is associated with poor outcomes (4). Eurthermore, depriving operating lung volumes (8). Increases in operating lung volumes have been associated with reduced swallow duration and patients of the enjoyment of food detracts from their quality of life. As use of NIV for acute respiratory failure has increased a probable increase in subglottic pressure (8). And greater sub( 1 ), determining how best to provide nutrition to these patients glottic pressures can, in turn, reduce the risk of aspiration (9). Unfortunately, the French investigators (5) did not measure has become a topic of great clinical relevance. In this issue of Critical Care Medicine, Terzi et al (5) lung volumes during the swallowing maneuvers. Nevertheless, it is likely that lung volumes were larger during NIV than durexplore the interaction between nasally delivered NIV and the ing unassisted breathing (10). breathing-swallowing mechanism in 15 patients with chronic A second potential explanation for improved swallowing obstructive pulmonary disease (COPD) when the patients with NIV could be the NIV-induced unloading of the respiwere able to breathe without ventilatory support for at least 2 ratory muscles and the concomitant decrease in carbon dioxhours. All of them were cared for in one ICU during an acute ide tension (10). In healthy subjects, experimentally-induced exacerbation of COPD. The investigators triggered swallowing hypercapnia and elastic loading increase respiratory frequency placing water boluses in the mouth of patients. These boluses and disrupt the normal breathing-swallowing coordinawere given during each of two conditions: unassisted respiration (11, 12). This pattern is similar to what was observed by tion and while on NIV. Compared with unassisted respiration, Terzi et al (5). When their patients were off NIV, there was an all patients demonstrated improved swallowing efficiency increase in arterial carbon dioxide tension and a likely increase while on NIV, with fewer swallows needed to clear the fluid in the mechanical load on the respiratory muscles (10). Similarly to what has been described in healthy subjects (11, 12), the increase in carbon dioxide tension and the likely increase 'See also p. 565. in mechanical load on the respiratory muscles were accompaKey Words: chronic obstructive pulmonary disease; noninvasive ventilation; nutrition; respirafory failure; sv^atlowing nied by a rise in respiratory frequency and a disruption in the Supported, in part, by Veterans Administration Research Service. normal breathing-swallowing coordination. These variables Dr. Shaikh is employed by the Veterans Administration. Dr. Laghi is emimproved during NIV. Could it be the respiratory rate alone is ployed by fhe Veterans Administration/Loyola University. His institution redriving the uncoordinated breathing-swallowing interactions? ceived grant support from fhe Veferans Administration Research Service. This is unlikely for two reasons. Eirst, breathing-swallowing Copyrighf © 2013 by fhe Society of Critical Care Medicine and Lippincoft interactions are preserved during exercise-induced tachypnea Williams & Wilkins (13). Second, even in patients with COPD who are clinically DOI: 10.1097/CCM.0000000000000002
F
Critical Care Medicine
www.ccmjournal.org
737
Editorials
stable, the prevalence of uncoordinated breathing-swallowing interactions is greater than that in healthy subjects (6). The finding of swallow-induced patient-ventilator uncoupling during NIV has been previously described by the French group (14) and is corroborated in the current study (5). Here, the investigators extend theirfindingsby testing an NIV machine connected to a novel patient-controlled off-switch pushbutton. The use of the pushbutton eliminated swallow-induced patientventilator uncoupling. On one hand, this is a predictable result considering that the ventuator would provide no mechanical breaths when the switch was in the off position. On the other hand, the restoration of the normal breathing-swallowing sequence of exhalation-swallow-exhalation is unexpected. This result could be of clinical relevance considering that the postswallow exhalation, which occurs in the vast majority of healthy subjects (8, 11, 12), is thought to prevent aspiration of residual material left in the pharynx after an initial deglutition (6). When the patients studied by Terzi et al (5) were disconnected from NIV, most swallows were followed by inspiration. This postswallow inhalation is similar to what Kijima et al ( 11 ) reported while healthy subjects sustained inspiratory elastic loads. In the latter study (11), postswallow inhalation was associated with coughing, which strongly implies that aspiration occurred as a result of swallowing (11). Despite the high prevalence of postswallow inhalation during unassisted breathing in the French study (5), no patient coughed. Whether this lack of cough resulted from the small volume of the fluid bolus used by the investigators or whether it reflected a low risk for aspiration or the presence of undetected microaspirations remains to be determined. The innovative study by Terzi et al (5) is provocative as it challenges preconceived ideas about the risk of aspiration in patients in respiratory failure. The investigators have set the stage for the study of breathing-swallowing dynamics in patients with acute exacerbations of COPD receiving NIV. The question now is to demonstrate whether oral feeding on NIV— with or without an off-switch pushbutton—is safe and can provide sufficient alimentation in selected patients in respiratory failure. A more fundamental challenge, however, is to demonstrate whether early oral feeding can improve the outcome of these patients—a formidable undertaking considering
738
wvvw.ccmjournal.org
the recent report that early initiation of "parenteral" nutrition in critically ill patients is associated with slower recovery and more complications, as compared with late initiation (15). Although these challenges are daunting, it is time to embrace them.
REFERENCES 1. Hill NS: Noninvasive positive-pressure ventilation. In: Principles and Practice of Mechanical Ventilation. Tobin MJ (Ed). New York, McGraw Hill, 2013, pp 447-494 2. Noguchi T, Shiga Y, Koga K, et al; A method to improve a gas leak on mask ventilation in the patient with a nasogastric tube. Anesthesiology 2001 ; 94:545 3. Macht M, Wimbish T, Bodine C, et al; ICU-acquired swallowing disorders. Crit Care Med 2013; 41:2396-2405 4. Artinian V, Krayem H, DiGiovine B: Effects of early enterai feeding on the outcome of critically ill mechanically ventilated medical patients. Chest 2006; 129:960-967 5. Terzi N, Normand H, Dumanowski E, et al: Noninvasive Ventilation and Breathing-Swallowing Interplay in Chronic Obstructive Pulmonary Disease. Crit Care Med 2014; 42:565-573 6. Gross RD, Atwood CW Jr, Ross SB, et al: The coordination of breathing and swallowing in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2009; 179;559-565 7. Nishino T, Hiraga K: Coordination of swallowing and respiration in unconscious subjects. J AppI Rhysiol 1991 ; 70:988-993 8. Gross RD, Atwood CW Jr, Grayhack JP, et al: Lung volume effects on pharyngeal swallowing physiology. J AppI Physiol 2003; 95:2211-2217 9. Logemann JA, Pauloski BR, Colangelo L: Light digital occlusion of the tracheostomy tube: A pilot study of effects on aspiration and biomeohanics of the swallow. Head Neck 1998; 20:52-57 10. Hussain C, Collins EG, Adiguzel N, et al; Contrasting pressure-support ventilation and helium-oxygen during exercise in severe COPD. Respir Med 2011 ; 105:494-505 11. Kijima M, Isono S, Nishino T: Modulation of swallowing reflex by lung volume changes. Am J Respir Crit Care Med 2000; 162:1855-1858 12. Hârdemark Cedborg Al, Sundman E, Boden K, et al: Co-ordination of spontaneous swallowing with respiratory airflow and diaphragmatic and abdominal muscle activity in healthy adult humans. Exp Physiol 2009; 94:459-468 13. Shaker R, Li O, Ren J, et al: Coordination of deglutition and phases of respiration; Effect of aging, tachypnea, bolus volume, and chronic obstructive pulmonary disease. Am J Rhysiol 1992; 263:G750-G755 14. Prigent H, Lejaille M, Terzi N, et al; Effect of a tracheostomy speaking valve on breathing-swallowing interaction. Intensive Care Med 201 2; 38:85-90 15. Casaer MP, Mesotten D, Hermans G, et al: Early versus late parenteral nutrition in critically ill adults. N EngI J Med 2011 ; 365:506-517
March 2014 • Volume 42 • Number 3
Copyright of Critical Care Medicine is the property of Lippincott Williams & Wilkins and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
