EDITORIAL
Rapid sequence intubation: What does it mean? Does it really matter? Chemical pneumonitis caused by aspiration during anesthesia is commonly referred to as Mendelson’s syndrome. Almost 70 years ago, a New York obstetrician, Dr. Curtis Mendelson was the first to connect the association of aspiration of stomach contents during obstetrical anesthesia and respiratory failure.[1] As stated by Dr. Mendelson in his original manuscript: “The aspirated material may include gastric juice, blood, bile, water or an association of them.” The original series included 44,016 deliveries over a 13 year period from 1932 to 1945. General anesthesia was provided by nitrous oxide and ether administered by face mask. Anesthetic care was complicated by aspiration in 66 women for incidence of 0.15%. There were two deaths that resulted from airway obstruction by solid food. In the remaining patients who aspirated liquid, dyspnea, cyanosis and tachycardia were noted. Despite the respiratory symptoms, there were no deaths and recovery was generally noted within 24-36 h even without the availability of endotracheal intubation and mechanical ventilation. Dr. Mendelson subsequently demonstrated that the acid was responsible for the asthma-like symptoms occurring following aspiration. He instilled into the respiratory tracts of rabbits a variety of substances including 0.1 Normal hydrochloric acid and vomitus (both untreated and neutralized). He not only demonstrated the pathogenesis of the syndrome, but was the first to recognize that specific conditions, in this case labor, could cause alterations in gastric emptying thereby predisposing patients to aspiration. His pioneering work in this area led to the use of the term “Mendelson’s syndrome” to describe respiratory failure secondary to pneumonitis from acid aspiration during anesthesia. Despite the reassuring outcome of the majority of the patients in the initial report of Dr. Mendelson, severe Access this article online Quick Response Code:
Website:
respiratory failure, prolongation of hospitalization, the need for invasive procedures such as high frequency oscillatory ventilation or extracorporeal membrane oxygenation or even death may result from perioperative acid aspiration.[2-4] Given the potential impact of acid aspiration on perioperative outcome, preventative measures were sought to prevent its occurrence. Following the animal data suggesting that the severity of injury is related to both the volume aspirated and its pH with cut-off values of 25 mL and pH less than 2.5 respectively, the use of agents to increase the pH and decrease the volume of the gastric contents has been suggested.[5] Despite limited evidence-based medicine, the pharmacologic control of gastric pH and volume is frequently used perioperatively. In 1961, Dr. Brian Sellick was the first to suggest the use of cricoid pressure to control the passive regurgitation of gastric contents during the induction of anesthesia. This maneuver is now commonly referred to as “Sellick’s maneuver.”[6-8] Additional advantages of cricoid pressure may include an improvement of the glottic view during difficult endotracheal intubation especially in neonates and infants.[7] Cricoid pressure is frequently combined with rapid sequence intubation (RSI) in an effort to prevent gastric aspiration. RSI involves the rapid and sequential administration of medications to induce general anesthesia and neuromuscular blockade. By definition, these medications are given in rapid succession without demonstration of effective bag-valve-mask ventilation in scenarios where it is believed that the risk-benefit ratio favors RSI over the small risk of cannot intubate – cannot ventilate scenario. In most clinical scenarios, anesthesia is induced with an intravenous anesthetic agent (thiopental, propofol, ketamine, etomidate) depending on the patient’s hemodynamic status and a rapidly acting neuromuscular blocking agent (originally succinylcholine).[9] As with many of the techniques outlined above, there is limited evidence based medicine to demonstrate the efficacy of either RSI or cricoid pressure.[10-12] However, given the potential consequences of acid aspiration, RSI has made its way into our airway management armamentarium.
www.saudija.org
DOI: 10.4103/1658-354X.130672
Saudi Journal of Anesthesia
As we discuss RSI, it becomes evident that there are differences among practitioners in their applications of these techniques. As with many techniques in our practice of airway management, there are practitioner-dependent Vol. 8, Issue 2, April-June 2014
Page | 153
Tobias: Rapid sequence intubation Page | 154
modifications such that additional terms have entered our vocabulary including classical RSI, modified RSI and even controlled RSI.[13] The survey in this issue of the Saudi Journal of Anesthesia clearly demonstrates that the use of these new terms lends further confusion to the discussion of the already controversial topic of RSI. In the survey, only 65% of respondents defined modified RSI as identical to RSI, but with mask ventilation. The majority of the respondents noted that they used a modified RSI if they were concerned about apnea time tolerance with traditional RSI. Appropriately so, the technique of modified RSI is commonplace in the pediatric population where a lower functional residual capacity after the induction of general anesthesia and neuromuscular blockade coupled with the higher oxygen consumption frequently leads to oxygen desaturation prior to endotracheal intubation. Other factors identified in the survey that would favor the use of a modified RSI included muscle pathology, which precludes the use of succinylcholine or any neuromuscular blocking agent. The authors are to be congratulated for taking the time to complete this survey. I personally found it extremely informative and well-conducted. It demonstrates a classic problem in any field including anesthesiology: Effective communication. It seems that any effort to clearly delineate the efficacy of any of these techniques needs to start with the development of agreeable definitions. Furthermore, the wide variation in practice demonstrated by this survey included many factors including the choice of neuromuscular blocking agent, the oxygen saturation level, at which bag-valve-mask ventilation would be initiated and the application of cricoid pressure. This variability is not unexpected given the lack of evidence-based trials to answer these questions. It appears that the only thing we can agree upon is one definitive take home message: “the majority of the responders agreed that modified RSI offers a lower incidence of complications than regular intravenous induction in pediatric patients at risk for aspiration.” So obviously, the next steps are to define the definitions and embark on the research to outline the most effective ways of accomplishing the goal, which remains the prevention of acid aspiration.
Vol. 8, Issue 2, April-June 2014
Joseph D. Tobias Department of Anesthesiology & Pain Medicine, Nationwide Children’s Hospital, The Ohio State University, Columbus, Ohio, USA Address for correspondence: Dr. Joseph D. Tobias, Department of Anesthesiology & Pain Medicine, Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, Ohio 43205, USA. E-mail: [email protected]
REFERENCES 1. 2. 3. 4. 5.
6. 7. 8. 9. 10.
11. 12. 13.
Mendelson CL. The aspiration of stomach contents into the lungs during obstetric anesthesia. Am J Obstet Gynecol 1946;52:191-205. Abdulla S. Pulmonary aspiration in perioperative medicine. Acta Anaesthesiol Belg 2013;64:1-13. Warner MA, Warner ME, Warner DO, Warner LO, Warner EJ. Perioperative pulmonary aspiration in infants and children. Anesthesiology 1999;90:66-71. Warner MA, Warner ME, Weber JG. Clinical significance of pulmonary aspiration during the perioperative period. Anesthesiology 1993;78:56-62. American Society of Anesthesiologists Committee. Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: Application to healthy patients undergoing elective procedures: An updated report by the American Society of Anesthesiologists Committee on Standards and Practice Parameters. Anesthesiology 2011;114:495-511. Sellick BA. Cricoid pressure to control regurgitation of stomach contents during induction of Anesthesia. Lancet 1961;2:404-6. Salem MR, Wong AY, Mani M, Sellick BA. Efficacy of cricoid pressure in preventing gastric inflation during bag-mask ventilation in pediatric patients. Anesthesiology 1974;40:96-8. Salem MR, Sellick BA, Elam JO. The historical background of cricoid pressure in anesthesia and resuscitation. Anesth Analg 1974;53:230-2. Tobias JD. Airway management in the pediatric trauma patient. J Intensive Care Med 1998;13:1-14. Butler J, Sen A. Towards evidence-based emergency medicine: Best BETs from the Manchester Royal Infirmary. BET 1: Cricoid pressure in emergency rapid sequence induction. Emerg Med J 2013;30:163-5. Loganathan N, Liu EH. Cricoid pressure: Ritual or effective measure? Singapore Med J 2012;53:620-2. Chewter M. Cricoid pressure; are we doing it right? J Perioper Pract 2011;21:342-5. Neuhaus D, Schmitz A, Gerber A, Weiss M. Controlled rapid sequence induction and intubation — An analysis of 1001 children. Paediatr Anaesth 2013;23:734-40.
How to cite this article: Tobias JD. Rapid sequence intubation: What does it mean? Does it really matter?. Saudi J Anaesth 2014;8:153-4.
Saudi Journal of Anesthesia
Copyright of Saudi Journal of Anaesthesia is the property of Medknow Publications & Media Pvt. Ltd. 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.
Rapid sequence intubation: What does it mean? Does it really matter? Chemical pneumonitis caused by aspiration during anesthesia is commonly referred to as Mendelson’s syndrome. Almost 70 years ago, a New York obstetrician, Dr. Curtis Mendelson was the first to connect the association of aspiration of stomach contents during obstetrical anesthesia and respiratory failure.[1] As stated by Dr. Mendelson in his original manuscript: “The aspirated material may include gastric juice, blood, bile, water or an association of them.” The original series included 44,016 deliveries over a 13 year period from 1932 to 1945. General anesthesia was provided by nitrous oxide and ether administered by face mask. Anesthetic care was complicated by aspiration in 66 women for incidence of 0.15%. There were two deaths that resulted from airway obstruction by solid food. In the remaining patients who aspirated liquid, dyspnea, cyanosis and tachycardia were noted. Despite the respiratory symptoms, there were no deaths and recovery was generally noted within 24-36 h even without the availability of endotracheal intubation and mechanical ventilation. Dr. Mendelson subsequently demonstrated that the acid was responsible for the asthma-like symptoms occurring following aspiration. He instilled into the respiratory tracts of rabbits a variety of substances including 0.1 Normal hydrochloric acid and vomitus (both untreated and neutralized). He not only demonstrated the pathogenesis of the syndrome, but was the first to recognize that specific conditions, in this case labor, could cause alterations in gastric emptying thereby predisposing patients to aspiration. His pioneering work in this area led to the use of the term “Mendelson’s syndrome” to describe respiratory failure secondary to pneumonitis from acid aspiration during anesthesia. Despite the reassuring outcome of the majority of the patients in the initial report of Dr. Mendelson, severe Access this article online Quick Response Code:
Website:
respiratory failure, prolongation of hospitalization, the need for invasive procedures such as high frequency oscillatory ventilation or extracorporeal membrane oxygenation or even death may result from perioperative acid aspiration.[2-4] Given the potential impact of acid aspiration on perioperative outcome, preventative measures were sought to prevent its occurrence. Following the animal data suggesting that the severity of injury is related to both the volume aspirated and its pH with cut-off values of 25 mL and pH less than 2.5 respectively, the use of agents to increase the pH and decrease the volume of the gastric contents has been suggested.[5] Despite limited evidence-based medicine, the pharmacologic control of gastric pH and volume is frequently used perioperatively. In 1961, Dr. Brian Sellick was the first to suggest the use of cricoid pressure to control the passive regurgitation of gastric contents during the induction of anesthesia. This maneuver is now commonly referred to as “Sellick’s maneuver.”[6-8] Additional advantages of cricoid pressure may include an improvement of the glottic view during difficult endotracheal intubation especially in neonates and infants.[7] Cricoid pressure is frequently combined with rapid sequence intubation (RSI) in an effort to prevent gastric aspiration. RSI involves the rapid and sequential administration of medications to induce general anesthesia and neuromuscular blockade. By definition, these medications are given in rapid succession without demonstration of effective bag-valve-mask ventilation in scenarios where it is believed that the risk-benefit ratio favors RSI over the small risk of cannot intubate – cannot ventilate scenario. In most clinical scenarios, anesthesia is induced with an intravenous anesthetic agent (thiopental, propofol, ketamine, etomidate) depending on the patient’s hemodynamic status and a rapidly acting neuromuscular blocking agent (originally succinylcholine).[9] As with many of the techniques outlined above, there is limited evidence based medicine to demonstrate the efficacy of either RSI or cricoid pressure.[10-12] However, given the potential consequences of acid aspiration, RSI has made its way into our airway management armamentarium.
www.saudija.org
DOI: 10.4103/1658-354X.130672
Saudi Journal of Anesthesia
As we discuss RSI, it becomes evident that there are differences among practitioners in their applications of these techniques. As with many techniques in our practice of airway management, there are practitioner-dependent Vol. 8, Issue 2, April-June 2014
Page | 153
Tobias: Rapid sequence intubation Page | 154
modifications such that additional terms have entered our vocabulary including classical RSI, modified RSI and even controlled RSI.[13] The survey in this issue of the Saudi Journal of Anesthesia clearly demonstrates that the use of these new terms lends further confusion to the discussion of the already controversial topic of RSI. In the survey, only 65% of respondents defined modified RSI as identical to RSI, but with mask ventilation. The majority of the respondents noted that they used a modified RSI if they were concerned about apnea time tolerance with traditional RSI. Appropriately so, the technique of modified RSI is commonplace in the pediatric population where a lower functional residual capacity after the induction of general anesthesia and neuromuscular blockade coupled with the higher oxygen consumption frequently leads to oxygen desaturation prior to endotracheal intubation. Other factors identified in the survey that would favor the use of a modified RSI included muscle pathology, which precludes the use of succinylcholine or any neuromuscular blocking agent. The authors are to be congratulated for taking the time to complete this survey. I personally found it extremely informative and well-conducted. It demonstrates a classic problem in any field including anesthesiology: Effective communication. It seems that any effort to clearly delineate the efficacy of any of these techniques needs to start with the development of agreeable definitions. Furthermore, the wide variation in practice demonstrated by this survey included many factors including the choice of neuromuscular blocking agent, the oxygen saturation level, at which bag-valve-mask ventilation would be initiated and the application of cricoid pressure. This variability is not unexpected given the lack of evidence-based trials to answer these questions. It appears that the only thing we can agree upon is one definitive take home message: “the majority of the responders agreed that modified RSI offers a lower incidence of complications than regular intravenous induction in pediatric patients at risk for aspiration.” So obviously, the next steps are to define the definitions and embark on the research to outline the most effective ways of accomplishing the goal, which remains the prevention of acid aspiration.
Vol. 8, Issue 2, April-June 2014
Joseph D. Tobias Department of Anesthesiology & Pain Medicine, Nationwide Children’s Hospital, The Ohio State University, Columbus, Ohio, USA Address for correspondence: Dr. Joseph D. Tobias, Department of Anesthesiology & Pain Medicine, Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, Ohio 43205, USA. E-mail: [email protected]
REFERENCES 1. 2. 3. 4. 5.
6. 7. 8. 9. 10.
11. 12. 13.
Mendelson CL. The aspiration of stomach contents into the lungs during obstetric anesthesia. Am J Obstet Gynecol 1946;52:191-205. Abdulla S. Pulmonary aspiration in perioperative medicine. Acta Anaesthesiol Belg 2013;64:1-13. Warner MA, Warner ME, Warner DO, Warner LO, Warner EJ. Perioperative pulmonary aspiration in infants and children. Anesthesiology 1999;90:66-71. Warner MA, Warner ME, Weber JG. Clinical significance of pulmonary aspiration during the perioperative period. Anesthesiology 1993;78:56-62. American Society of Anesthesiologists Committee. Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: Application to healthy patients undergoing elective procedures: An updated report by the American Society of Anesthesiologists Committee on Standards and Practice Parameters. Anesthesiology 2011;114:495-511. Sellick BA. Cricoid pressure to control regurgitation of stomach contents during induction of Anesthesia. Lancet 1961;2:404-6. Salem MR, Wong AY, Mani M, Sellick BA. Efficacy of cricoid pressure in preventing gastric inflation during bag-mask ventilation in pediatric patients. Anesthesiology 1974;40:96-8. Salem MR, Sellick BA, Elam JO. The historical background of cricoid pressure in anesthesia and resuscitation. Anesth Analg 1974;53:230-2. Tobias JD. Airway management in the pediatric trauma patient. J Intensive Care Med 1998;13:1-14. Butler J, Sen A. Towards evidence-based emergency medicine: Best BETs from the Manchester Royal Infirmary. BET 1: Cricoid pressure in emergency rapid sequence induction. Emerg Med J 2013;30:163-5. Loganathan N, Liu EH. Cricoid pressure: Ritual or effective measure? Singapore Med J 2012;53:620-2. Chewter M. Cricoid pressure; are we doing it right? J Perioper Pract 2011;21:342-5. Neuhaus D, Schmitz A, Gerber A, Weiss M. Controlled rapid sequence induction and intubation — An analysis of 1001 children. Paediatr Anaesth 2013;23:734-40.
How to cite this article: Tobias JD. Rapid sequence intubation: What does it mean? Does it really matter?. Saudi J Anaesth 2014;8:153-4.
Saudi Journal of Anesthesia
Copyright of Saudi Journal of Anaesthesia is the property of Medknow Publications & Media Pvt. Ltd. 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.
