Dr. Braude is an assistant professor of emergency medicine at the University of New Mexico School of Medicine, the medical director of PHI Air Medical of New Mexico, both in Albuquerque, a co-director of the Emergency Airway Training Program at the University of New Mexico, and a co-director of the National Procedural Sedation Course.
An attending emergency physician, an emergency medicine resident, and the entire trauma team are caring for a critical patient. In the typical chaos of a teaching hospital trauma room, there is a miscommunication between the physicians and nurses. The doctors think they ordered etomidate and succinylcholine; the nurses only heard the order to give the etomidate, and are awaiting direction to give succinylcholine. The doctors unknowingly proceed with laryngoscopy. The patient vomits and aspirates.
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Rapid sequence intubation (RSI) has become a trademark procedure in our specialty, and is now the most common method for airway control in teaching hospital emergency departments, according to the National Emergency Airway Registry database. (Ann Emerg Med 2000;36:S51.) Use of a neuromuscular blocker is a fundamental step in RSI, allowing oral intubation in a non-flaccid patient, preventing vomiting, and improving the view obtained at laryngoscopy. Whether by accident or intent, oral intubation with the use of an induction agent alone is not RSI but rather sedation-facilitated intubation (SFI).
Sedation-facilitated intubation works well in fasted patients, but performs poorly in the ED and the field
SFI is intuitively appealing because it eliminates the risks of paralysis, especially when the provider anticipates a difficult intubation, but it is problematic for several reasons. When given to fragile patients rather than healthy patients requiring procedural sedation, sedative agents such as midazolam or etomidate may produce apnea and blunt the patient's ability to protect his airway without blocking the gag reflex or ability to vomit. This is a set-up for aspiration. The sedative alone does not overcome muscle tone like a paralytic does, thus failing to optimize laryngoscopy. An inadequately sedated and paralyzed patient is probably more likely to develop increased intracranial pressure during laryngoscopy, which is significant because many patients undergo emergency intubation because of intracranial injuries or spontaneous bleeds.
While SFI may be safe and successful in elective intubations of fasted patients not predicted to have difficult airways in the operating room or semi-elective intubations of fasted patients in the ICU, it performs poorly in the emergency department and prehospital settings. Several recent papers demonstrate that this approach is associated with a lower success rate than RSI although the available literature is mostly from the prehospital setting and often retrospective and small in size with little data on complications.
In the teaching hospital emergency department, Walls et al report a first course success rate of 98.7 percent with RSI, compared with 90.2 percent for SFI. (Ann Emerg Med 2000;36:S51.) Complications are not reported by technique. This may seem to be a small difference, but it can have important implications in this critical patient population, especially when associated with the potential for serious complications. In a recent prospective trial in air medical patients, Bozeman and colleagues compared etomidate-only intubations with RSI. (Prehosp Emerg Care 2006;10:8.) The laryngoscopic view was graded as good or acceptable in 79 percent of RSI patients but in only 13 percent of etomidate-only patients. The final success rate was 92 percent with RSI and only 25 percent with etomidate. There were no serious complications reported. In another air medical study, Kociszewski et al report a success rate of 87 percent with etomidate alone compared with 98 percent for RSI, with the etomidate-only group twice as likely to require multiple attempts. (Am J Emerg Med 2000;18:757.) They did not report on complications.
Intubating in the Field
Wang and colleagues report a success rate of only 62.5 percent with the use of midazolam for SFI by paramedics on the ground. They did not have a comparison RSI group. (Prehosp Emerg Care 2000;4:14.) An article currently at press for Annals of Emergency Medicine by Jacoby and colleagues from Bethlehem, PA compared the prehospital use of etomidate or midazolam without a paralytic for SFI. The overall intubation success rate was 76 percent, according to their abstract. They do not report on complications.
Many EMS systems have adopted SFI to avoid the risks and politics associated with prehospital RSI. This may occur by intent in treatment guidelines and protocols or surreptitiously. A couple of times a year, I answer a radio or phone call from a paramedic in a non-RSI service caring for a patient he believes would benefit from intubation. The patient is usually combative or has trismus following severe head trauma. The paramedics have often attempted nasal intubation before calling, and request orders for Valium to “knock the patient down” and allow intubation, i.e., sedation-facilitated intubation. As you can imagine, my answer is always “no,” lest we repeat our trauma room experience in the field. In this setting, the most appropriate course of action is basic airway management with rapid transport. In long transport times, consider rendezvous with a ground or air service that can perform RSI if available.
In the case of a predicted difficult airway, the very situation in which many providers are drawn to SFI, embarking on a procedure with a proven lower success rate and a high potential for complications is probably not the wisest course of action. Appropriate options in this circumstance include calling for help, preparing adjuncts such as a bougie and back-up airways (e.g., LMA, Combitube, King LT), blind nasotracheal intubation, awake oral intubation, or double set-up for surgical airway.
I have been doing this long enough to “never say never,” but it seems that SFI should be discouraged in patients who haven't fasted, especially when RSI is available. The weight of evidence would make complications from this practice difficult to defend. In the emergency department, RSI with appropriate training and quality assurance should be the standard of care for airway management.
© 2006 Lippincott Williams & Wilkins, Inc.