In Response

Abstract

We thank Dr. Sherlock for sharing her experience as part of the Tasmanian ambulance service.1 Learning and excelling at ventilation skills is, in our opinion, just as important (if not more) as obtaining proficiency at intubation. To address her specific question, our study group came from different municipalities, and there were different ways of measuring end-tidal carbon dioxide concentration; yet most of the time, it was measured using a capnometer. Our patients were extremely ill with high Injury Severity Scores and low Glasgow Coma Scale, and the conditions in which these intubations were performed were extremely difficult. We believe that the reported incidence of misplaced endotracheal tubes (ETT) stems from a variety of reasons, an important one being the relatively low frequency that the procedure is performed; it is also important to recognize that detection of end-tidal carbon dioxide concentration in patients in shock is not always possible under all circumstances, adding to the confounding factors that make it difficult to ascertain where the tip of an ETT is positioned. Dr. Shatz expressed concern that our article misrepresented the airway skills of Miami-Dade paramedics.2 The definition of “endotracheal intubation” is simply the passage of an ETT through the vocal cords and that was the definition used in our study. When an airway is not secured by means of an ETT, oxygenation and ventilation must be achieved by other (rescue) methods. These interventions include the use of supraglottic devices (such as a laryngeal mask airway [LMA] or Combitube®) or performing a cricothyroidotomy. Dr. Shatz takes issue with the placement of an LMA by the anesthesiologists in the operating room as an adequate airway. There is, however, a big difference between the use of an LMA in a completely elective and controlled setting, where not only the risks of aspiration are minimal but also the positioning, hemodynamics, and spontaneous ventilation are carefully considered. As anesthesiologists with many combined years in the field of Trauma Anesthesia, we can say that having to resort to an LMA in the chaotic setting of a Trauma Bay, after not being able to secure the airway with an ETT, is a life-saving maneuver but far from ideal, especially in critically ill patients considered at risk for aspiration of gastric contents. Placing a supraglottic airway in such circumstances is only a temporary measure until a definitive airway can be obtained. This is the exact scenario that paramedics face frequently but under even less ideal conditions. Having clarified the above, we found no mortality difference when comparing the groups, which points to the fact that we may be asking the wrong question by only looking at intubation rates instead of assessing transport time or adequacy of oxygenation and ventilation, which may be more important. Of special concern is the statement raised by Dr. Shatz regarding the raw data used in the article. The intent of the study was never to compare the success rates of air versus ground crews. Having found a significant difference, we offered a possible explanation in the context of the area studied and international data, yet we explicitly stated “this study did not correlate intubation skills of individual paramedics.”3 We believe that repeated exposure to airway management in the field should improve intubation skills and that it would be worthwhile to undertake a study comparing the success rates of intubation according to the number of procedures performed. Regarding the insightful comments of Dr. Pouliot,4 limiting the number of paramedics and targeting their response as a way to prevent skill dilution is certainly an interesting concept that worth further study. Finally, we reemphasize that performing tracheal intubation in the field is an extremely difficult task and the paramedics of Miami-Dade should be commended for their extraordinary commitment and dedication. Miguel Cobas, MD Keith Candiotti, MD Albert J. Varon, MD Department of Anesthesiology and Perioperative Medicine Miller School of Medicine University of Miami Miami, Florida [email protected]