Prehospital Advanced Life Support for Major Trauma: Critical Need for Clinical Trials

CONCEPTS

Prehospital Advanced Life Support for Major Trauma: Critical Need for Clinical Trials From the Arizona Emergency Medicine Research Center, Health Services Research Program, Section of Emergency Medicine, Department of Surgery, University of Arizona, Tucson, AZ. Received for publication October 6, 1997. Revision received April 8, 1998. Accepted for publication April 28, 1998.

Daniel W Spaite, MD Elizabeth A Criss, RN, MAEd Terence D Valenzuela, MD Harvey W Meislin, MD

personnel. We compared and contrasted the literature that currently exists on this topic. We examined methodologies, results, and conclusions for each article. We also stress the need for critical clinical evaluations in this arena. [Spaite DW, Criss EA, Valenzuela TD, Meislin HW: Prehospital Advanced Life Support for major trauma: Critical need for clinical trials. Ann Emerg Med October 1998;32:480-489.]

Copyright © 1998 by the American College of Emergency Physicians.

INTRODUCTION 0196-0644/98/$5.00 + 0 47/1/93131

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Since the inception of prehospital care there has been an ongoing debate over the use of Advanced Life Support (ALS) measures in the out-of-hospital management of trauma victims. The debate centers around the assumption that the benefit of the various procedures available to the ALS provider (ie, intravenous access and intubation) must be weighed against the delay to definitive care that would result from a prolonged on-scene interval (OSI). There is no doubt that trauma system development has profoundly affected the likelihood of survival from severe injury.1-6 Some authors attribute the increased survival to the ability of prehospital providers to establish an airway and treat shock.1-9 Many others, however, conclude that the increased survival rate is primarily a result of decreased time to surgical intervention.10-14 To date, the literature surrounding prehospital trauma care has been simplistic in its approach to evaluating the effect of ALS on patient outcome. The literature reports discussed in the following sections represent the bulk of the body of knowledge in the continuing debate over outof-hospital patient management. As this review points out, these studies frequently used a flawed base on which to build their research, and often report a cause-and-effect relationship between ALS and patient outcome without complete information. Prehospital trauma care is an important aspect in the development of a trauma system; therefore it is important that care be taken to develop methodologically sound research that will provide definitive answers to this ongoing debate.

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ALS FOR MAJOR TRAUMA Spaite et al

THE ARGUMENT AGAINST ON-SCENE ALS IN TRAUMA CARE

Most authors who oppose the use of ALS for trauma care at the scene use the rationale that it wastes precious time that could be used in rapidly moving the patient to “definitive care.” A review of these publications reveals many of them are little more than editorials based on indirect data, theoretical arguments, and literature reviews from other editorials (Table 1). When the studies with actual data are carefully evaluated for methodology and limitations, it becomes clear that the conclusions generally do not logically follow from the data presented. In a retrospective study of penetrating cardiac wounds, Gervin and Fischer10 analyzed the “impact” of prehospital time intervals on mortality rates. Group 1 patients had transport intervals less than or equal to 9 minutes from “ambulance” arrival at the scene to “definitive care” in the emergency department. The mean transport interval in group 2 was 25 minutes. In group 2, the authors attributed the delay to “prolonged attempts at stabilization in the field.” Eighty-three percent (5/6) of group 1 patients survived, whereas there were no survivors in group 2 (0/7). The conclusion of this study was that prompt transport to a hospital, without attempts at field resuscitation, provides a better chance for survival among patients with penetrating heart wounds. This is a classic “apples and oranges” study. The groups were unmatched in many respects. In group 1, 50% of the patients had gunshot wounds compared with 71% of those in group 2, giving group 1 patients an inherent survival advantage. Not all patients arrived at the hospital by ambulance. Two patients in group 1 were actually transported by private vehicle. Group 1 intervals were described as “short,” but no data were given to support this claim. Group 1 may have had greater survival simply because they were injured closer to the hospital. Also, some of the patients in group 2 were in cardiac arrest before arrival at the hospital. None of the group 1 patients had cardiac arrest in the out-of-hospital environment. Therefore group 2 included patients that were, in essence, dead on arrival, whereas group 1 had none. Other major problems were that the sample size was very small and the study was retrospective. Actual times to definitive surgical care were not known. The difference in mortality between the groups could be attributable to a delay in surgical care after arrival in the ED, so the use of arrival at the ED as synonymous with“definitive care” was erroneous. In addition, there was no trauma system in place at the time of this study. Thus one of the most highly touted “studies” supporting the “scoop and run” approach to prehospital

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trauma care was retrospective, extremely small, and filled with unsupported conclusions. In 1984 Cayten et al11 evaluated 102 trauma patients transported in New York City by either ALS or Basic Life Support (BLS) units.11 A total of 65 patients were transported by BLS and 37 by ALS providers. The study reported a significantly longer OSI for ALS providers (25 minutes for ALS versus 17 minutes for BLS, P