Emergency Medicine

Medications can aid endotracheal intubation of critically ill or injured patients who are not in cardiac arrest

Paramedics often have to insert a breathing tube into the trachea (endotracheal intubation, ETI) of critically ill or injured patients to enable them to breathe. However, compared with patients in cardiac arrest, ETI of patients who are not in cardiac arrest can be more difficult because of protective airway reflexes like the gag reflex or clenched jaw, which resist tube insertion. Use of medications such as sedatives and/or neuromuscular blocking agents to depress or ablate protective airway reflexes can aid ETI, according to a preliminary study. Henry E. Wang, M.D., M.P.H., of the University of Pittsburgh School of Medicine, and colleagues analyzed clinical ETI data reported on standard forms by rescuers from 42 emergency medical services systems. They defined successful ETI as intratracheal placement of the endotracheal tube on the last ETI attempt.

Rescuers reported the presence and ablation of six protective airway reflexes: gag reflex, clenched jaw, inadequate relaxation, combativeness, laryngospasm, and seizure/myoclonus (sudden jerking movements). Of 1,953 ETIs, nearly 11 percent used drug-assisted intubation (DAI). DAI was nearly 13 times more likely to be successful with ablation of the gag reflex and was also much more likely to be successful with ablation of clenched jaw, inadequate relaxation, and combativeness.

Ablation of selected and all protective airway reflexes was associated with DAI success. On the other hand, ablation of individual reflexes did not necessarily lead to DAI success.

Patient anatomic factors and operator skill still play key roles in ETI efforts. Thus, protective reflexes, anatomic features, and operator skills must all be considered when attempting to characterize DAI performance or the effectiveness of specific drug facilitation regimens, suggest the researchers. Their study was supported in part by the Agency for Healthcare Research and Quality (HS13628).

See "Drug-assisted effects on protective airway reflexes during out-of-hospital endotracheal intubation (preliminary report)," by Christopher D. Cole, M.D., Dr. Wang, Benjamin N. Abo, B.S., N.R.E.M.T.-P., and Donald M. Yealy, M.D., in the October 2006 Prehospital Emergency Care 10(4), pp. 472-475.

Editor's Note: A related study (HS13628) by the same researchers concludes that basic emergency medical technicians can be trained to perform more advanced cardiac resuscitation interventions such as administration of resuscitative medications and invasive airway support. This could expand their role beyond use of cardiac defibrillators and chest compressions. For more details, see Guyette, F.X., Rittenberger, J.C., and Platt, T. (2006, October-December). "Feasibility of basic emergency medical technicians to perform selected advanced life support interventions." Prehospital Emergency Care 10(4), pp. 518-521.

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