Emergency Tracheal Intubation: Techniques and Outcomes Maggie W Mechlin MD and William E Hurford MD Location Prehospital Emergency Department ICUs Personnel Prehospital Providers Respiratory Therapists Pulmonologists Attending Presence in Teaching Hospitals Techniques Direct Laryngoscopy Video Laryngoscopy Blind Nasal Intubation Supraglottic Devices Medications Sedatives and Anesthetics Neuromuscular Blocking Agents Multiple Attempts at Intubation Conclusions Performing emergency endotracheal intubation necessarily means doing so under less than ideal conditions. Rates of first-time success will be lower than endotracheal intubation performed under controlled conditions in the operating room. Some factors associated with improved success are predictable and can be modified to improve outcome. Factors to be discussed include the initial decision to perform endotracheal intubation in out-of-hospital settings, qualifications and training of providers performing intubation, the technique selected for advanced airway management, and the use of sedatives and neuromuscular blocking agents. Key words: emergency treatment; equipment and supplies; laryngoscopes; respiration, artificial; respiratory therapy; resuscitation. [Respir Care 2014;59(6):881–894. © 2014 Daedalus Enterprises] Introduction gencies will occur. Even in the hospital, despite advances in monitoring and management, the need for urgent or Emergency endotracheal intubation will always be nec- emergent endotracheal intubation occurs with regular fre- essary because we cannot predict when accidents or emer- quency. The procedure is made difficult because usually there is no time for a detailed history and physical exam- The authors are affiliated with the Department of Anesthesiology, Uni- versity of Cincinnati, Cincinnati, Ohio. This study was supported by funds from the Department of Anesthesi- ology, University of Cincinnati. The authors have disclosed no conflicts Drs Mechlin and Hurford are co-first authors. of interest. RESPIRATORY CARE • JUNE 2014 VOL 59 NO 6 881 EMERGENCY TRACHEAL INTUBATION Table 1. Common Problems Associated With Emergency intubation that was a failure, with no further attempts made.9 Endotracheal Intubation Unfortunately, the study did not examine how responders made decisions regarding whether to attempt intubation. Limited ability to examine the airway The causes of failed attempts, whether it be inadequate Limited equipment and positioning Limited back-up exposure, inability to use medications to facilitate intuba- Difficult, often inadequate pre-oxygenation tion, or other reasons, were also not examined. Presence of co-existing life-threatening conditions There is no benchmark for success of prehospital intu- bation that would help interpret these numbers. Certainly, it would be inappropriate to judge success rates against intubation of relatively healthy patients in the operating ination or discussion and planning among the health care room. A more reasonable comparison might be intubations team (Table 1). Some factors, however, are predictable performed in the emergency department (ED), although and can be modified to improve the likelihood of success this setting still provides more favorable conditions for and a favorable outcome. successful intubation than a prehospital setting. In a group of 314 trauma subjects, the success of endotracheal intu- Location bation in the field and in the ER was similar: 83% were intubated in the field on the first attempt, and 86% in the Prehospital ED. Only 2% of the field intubations and 1% of the ED intubations required as many as 4 attempts.8 Reasonable controversy exists as to what, if any, pre- hospital advanced airway management should occur in Return of Spontaneous Circulation. The occurrence and patients requiring respiratory support. The best advanced time elapsed before ROSC are important outcomes of the airway to use is also a matter of debate. Clearly, some of management of patients with OHCA. One of the more this decision making depends upon the personnel avail- robust studies examined 649,359 OHCA subjects in Japan; able, their level of experience, and their familiarity with 57% of the subjects were managed with bag-mask venti- emergency airway management. lation (BMV), and 43% had an advanced airway placed Most of the studies on prehospital airway management (6% of total enrolled subjects had an endotracheal tube are with patients suffering out-of-hospital cardiac arrest (ETT) placed; 37% received a supraglottic airway). The (OHCA). The outcomes that have been examined include subjects who had an advanced airway placed had lower return of spontaneous circulation (ROSC), neurologic se- rates of ROSC compared with those transported with BMV quel survival to hospital admission, survival to hospital alone (7.0 vs 5.8%, P Ͻ .001).2 In the report by Studnek discharge, and ease and success of airway placement.1-11 et al,9 using BMV and not attempting intubation were associated with an adjusted odds ratio (OR) of 2.33 in Success With Endotracheal Intubation. Studnek et al9 achieving ROSC (adjusted for first rhythm) compared with retrospectively studied 1,142 OHCA subjects to determine subjects who were intubated on the first attempt. Perhaps whether the type of airway management chosen influenced since ROSC is dependent upon the patient receiving high- the rate of ROSC. They also evaluated the success and quality and consistent chest compressions, interruption of frequency of different types of airway management. Fifty compressions during intubation and distraction of health percent of subjects were successfully intubated on the first care providers during the procedure may be responsible attempt; 26% had more than one attempt at intubation for the poorer outcomes. (12% of the total population was successfully intubated Not all studies, however, are in agreement with this with multiple attempts; 14% were unable to be intubated point. Nagao et al7 examined 355 OHCA subjects and despite multiple attempts); 18% did not have any attempt reported higher rates of ROSC in subjects with advanced at intubation; and the remaining 6% had one attempt at airways placed compared with BMV management (18.6 vs 10.3%, P ϭ .035). Likewise, studying 2,586 OHCA sub- jects, Takei et al,10 reported increased rates of ROSC in those subjects managed with an ETT compared with ad- Dr Hurford presented a version of this paper at the 52nd Respiratory Care Journal Conference on Adult Artificial Airways and Airway Adjuncts, vanced airways other than an ETT and those managed held June 14–15, 2013, in St. Petersburg, Florida. with BMV alone (30.0, 20.2, and 21.3%, respectively, P ϭ .003). Correspondence: William E Hurford MD, Department of Anesthesiol- ogy, PO Box 670531, 231 Albert Sabin Way, Cincinnati, OH 45267- 2 0531. E-mail: [email protected]. Neurologic Outcome. Hasegawa et al reported that 1-month neurologic outcomes for OHCA subjects were DOI: 10.4187/respcare.02851 more favorable in patients managed with BMV alone (2.9% 882 RESPIRATORY CARE • JUNE 2014 VOL 59 NO 6 EMERGENCY TRACHEAL INTUBATION of total OHCA subjects) compared with advanced airways tive-pressure ventilation may impede venous return and (1.1%), although both are abysmally low rates. They con- worsen the low-flow state. cluded that the use of both ETT and supraglottic devices The American Heart Association updated the guidelines was an independent predictor of untoward neurologic out- for advanced cardiac life support in 2010. Their statement come. regarding advanced airway management points out that “there is no evidence that advanced airway measures im- Survival and Hospital Discharge. Several studies have prove survival rates in the setting of out-of-hospital car- examined the influence of prehospital airway management diac arrest.”18 More recent evidence continues to support on survival following various time periods. In the study by this conclusion.2 In the absence of specific indications to Hasegawa et al2 of OHCA subjects in Japan, those man- secure an advanced airway, the evidence favors mask ven- aged with BMV had a 1-month survival of 5.3% compared tilation alone in this setting. with 3.9% for those managed with an advanced airway. Studnek et al9 reported an increased rate of survival to hospital discharge in OHCA subjects managed with BMV Emergency Department only compared with those who were intubated on the first attempt. The literature remains divided, however, on this Walls et al19 set out to better determine the character- point, with some researchers reporting no difference with istics of intubations in the ED in terms of indications, airway management between survival at 1 month and at 1 techniques, rates of success, and unplanned events in a year10 and others reporting a nonstatistically significant multi-center study that included 31 EDs and 8,937 subjects trend toward improved survival to hospital discharge in over a period of 5 y. Most of the subjects presented with 7 patients receiving advanced airway management. medical rather than traumatic problems, and most were In a subgroup of patients suffering from severe trau- intubated using rapid-sequence intubation (RSI; 69% of all matic brain injury, defined as having a Glasgow coma subjects and 84% of subjects who received medications to Ͻ scale score of 8, there are unclear data regarding how facilitate intubation). The first-attempt success rate was 12 the choice of whether to intubate impacts survival. There 95%, and 99% of subjects eventually received a successful is,