We read with interest the prospective trial by Schmidt et al .1and the accompanying editorial,2which suggest that faculty supervision during emergency endotracheal intubations decreases the rate of airway complications. However, as with any observational study, confounders must be considered.

First, several variables suggest that the set of intubations supervised by faculty anesthesiologists may have been slightly less emergent than those accomplished without faculty supervision. The reasons for intubation in the supervised group were more commonly airway protection and “other.” The supervised group was more likely to use neuromuscular blockade to accomplish tracheal intubation. The supervised group performed a higher proportion of intubations in the intensive care unit, a setting in which decompensating patients are more likely to be recognized before complete physiologic deterioration. Moreover, unlike some floor settings, intensive care unit beds are uniformly equipped with functioning suction, oxygen, and devices to deliver positive pressure mask ventilation and staffed by support personnel who are more experienced in identifying, mobilizing and participating in emergent clinical scenarios. Regardless of location, urgent and semiemergent intubations are more likely to allow time to assemble a full complement of personnel and equipment, to optimize patient position, and to consider aspiration prophylaxis, all of which should minimize risk of various complications.

Second, as the authors suggest, the presence of a second anesthesia provider, irrespective of the level of training or experience, may facilitate safer tracheal intubation. Based on a multivariate logistic regression analysis of data collected in a prospective multicenter study,3tracheal intubation managed by an anesthesia team (including a junior and a senior provider) as opposed to a single senior provider, was shown to protect against airway complications. Our institution's experience and data support the conclusion that a second anesthesia provider, as opposed to a faculty anesthesiologist, is the process characteristic responsible for improved outcomes. The emergency intubation team at our institution includes a junior (CA-1 or CA-2) and senior anesthesiology resident (CA-3 with at least 24 months of laryngoscopic experience). Typically, a faculty member is present when difficult intubation is anticipated. Preliminary analysis of the electronic medical records for 2,460 emergent intubations over a 4-yr period revealed a 2.3% composite complication rate, with no differences based on faculty presence. Operator-reported complications included aspiration (n = 37), dental injury (n = 4), and esophageal intubation (n = 15). Of note, 8.4% of tracheal intubations were accomplished with the aid of a bougie introducer. The availability of this adjunct or providers' experience in its use was not presented by Schmidt et al . This may be responsible for the rate of frequent esophageal intubation in their studied population.

Finally, time of day has been shown to affect survival to discharge after cardiopulmonary arrest.4The data collection sheet used by Schmidt et al ., which was presented in previous work,5includes the date and time of intubation. An analysis to evaluate the effect of nighttime or weekend intubations would be helpful. If nighttime intubations, or weekend intubations, or both, result in more complications, the explanation may be decreased faculty presence, but may also be a result of decreased nursing vigilance delaying the recognition of a need for emergency intubation, increased time from code activation to presence of the anesthesiology team, or circadian biologic factors in both patients and staff attempting the intubation.

Faculty presence is the standard of care for intubations in the operating room. Extending this standard to emergency intubations would be desirable if it were to improve patient safety. However, undesirable effects on perioperative patient safety and healthcare costs must also be considered. During nights, weekends, and other periods of limited staffing, emergency intubations may pull on-call faculty away from the operating room or intensive care unit. Dedicated faculty to cover emergent intubations will entail increased on-call commitments and economic costs in many centers. These concerns justify a prospective study in either the intensive care unit or the floor with systematic or even randomized allocation of faculty presence to clarify the contribution of faculty anesthesiologists, urgency, location, time of day, and other confounders on significant patient airway outcomes.

*University of Michigan Health System, Ann Arbor, Michigan. jmmhyre@umich.edu

Schmidt UH, Kumwilaisak K, Bittner E, George E, Hess D: Effects of supervision by attending anesthesiologists on complications of emergency tracheal intubation. Anesthesiology 2008; 109:973–7
Boylan JF, Kavanagh BP: Emergency airway management: Competence versus  expertise? Anesthesiology 2008; 109:945–7
Jaber S, Amraoui J, Lefrant JY, Arich C, Cohendy R, Landreau L, Calvet Y, Capdevila X, Mahamat A, Eledjam JJ: Clinical practice and risk factors for immediate complications of endotracheal intubation in the intensive care unit: A prospective, multiple-center study. Critical Care Med 2006; 34:2355–61
Peberdy MA, Ornato JP, Larkin GL, Braithwaite RS, Kashner TM, Carey SM, Meaney PA, Cen L, Nadkarni VM, Praestgaard AH, Berg RA: Survival from in-hospital cardiac arrest during nights and weekends. JAMA 2008; 299:785–925
Benedetto WJ, Hess DR, Gettings E, Bigatello L, Toon H, Hurford WE, Schmidt U: Urgent tracheal intubation in general hospital units: An observational study. J Clin Anesthesia 2007; 19:20–4