Prehospital Physiologic Data and Lifesaving Interventions in Trauma Patients

Military Medicine, Jan 2005 by Holcomb, John B, Niles, Sarah E, Miller, Charles C, Hinds, Denise, Et al

Background: The ability to accurately triage trauma patients can be difficult in the prehospital environment. Prehospital trauma scoring systems have been developed with a goal of determining which patients should be transported immediately to a trauma center, thus benefiting from critical personnel and resource-intensive lifesaving interventions (LSIs). A resource-based endpoint, LSIs, therefore might be the optimal endpoint of prehospital triage scoring and could be used to determine where patients are transported. We hypothesized that simple physiologic data available immediately upon scene arrival would prove predictive of the need for a LSI. Methods: Trauma patients transported from the injury scene by helicopter were eligible for entry into the study. Prehospital physiologic data and interventions were timed and recorded by flight medical personnel, whereas hospital vital signs, injuries, and interventions were prospectively recorded from the inpatient records. The motor component of the Glasgow Coma Scale was used as an indicator of neurologic function. LSIs were procedures deemed lifesaving by a multidisciplinary panel of trauma experts. Results: Physiologic data were collected from August 2001 to February 2002. Data were collected for 216 random patients transported by the Life Flight helicopter service. There were no differences between LSI and non-LSI patients in age, gender, or transport time, and 80 patients underwent 197 LSIs. The mean age was 33 � 17 years, 73% of patients were male, 90% suffered blunt injury, the injury severity score was 14 � 9, hypotension (systolic blood pressure of

Introduction

The ability to accurately triage trauma patients can be problematic in prehospital environments. Many prehospital triage scores have been developed to facilitate this process, perhaps demonstrating that a good deal of uncertainty remains in these methods.1-18 The primary reason to perform prehospital scoring is to determine whether patients should be transported immediately to a trauma center (TC) and thus benefit from the TC's ability to rapidly provide lifesaving interventions (LSIs), resulting in the survival of patients who would otherwise have died.19-26

The potential benefit of TCs is related to the concentration of experienced personnel and technology at one location that specializes in the care of seriously injured patients. Organized TCs have been shown to decrease rates of preventable death in the intermediate group of patients who arrive seriously ill. Mortality rates in current mature TCs are approximately 3% of admissions, and death usually occurs among patients who have devastating injuries and a very low probability of survival, despite very aggressive diagnostic and interventional maneuvers.27 Using death as the primary endpoint of a prehospital triage tool identifies only the small numbers of patients who received LSIs and died at the TC, rather than those who received LSIs and benefited from the interventions. Others have recommended using an injury severity score (ISS) of > 15 as an indicator of appropriate triage; however, these data are not available until hospital discharge. This highlights the fact that, although ISS is often appropriately used to retrospectively compare outcomes between groups of patients, the data that are used to compile the ISS are not available until discharge from the hospital. Therefore, the ISS is not a tool that can be used for prehospital or even emergency department triage. More importantly, up to 25% of patients with low ISSs (scores of 1-9) required the resources available at TCs.27

A more useful prehospital triage tool would identify patients who actually required a LSI.28 This resource-based triage end-point would focus on patients who were transported to a TC and received and benefited from LSIs.9 Those who were transported to a TC, did not receive LSIs, and survived would represent the group that perhaps could have been transported to a non-TC and fared just as well. Many studies have demonstrated that trauma systems have not developed a sensitive and specific prehospital triage tool capable of identifying patients who would or would not benefit from evaluation at the TC.29,30 In an initial attempt to develop a prehospital triage tool based only on prehospital data whose endpoint is resource based, we hypothesized that physiologic data immediately available upon scene arrival would prove predictive of the need for a LSI.

Methods

A random convenience sample of trauma patients transported from the scene, by a Life Flight system helicopter, to Memorial Hermann Hospital, an urban, level I TC in Houston, Texas, between August 1, 2001 and March 7, 2002 (7 months), were eligible for the study. This study was approved by the Committee for the Protection of Human Subjects of the University of Texas Health Science Center at Houston. The Life Flight helicopter service consists of three Eurocopter BK 117B helicopters. An experienced pilot, flight medic, and nurse constitute the helicopter flight crew. Trauma patients discharged home from the emergency department (25%) were not included in this data set. Patient inclusion criteria were as follows: (1) transport directly from the incident scene and (2) an injury necessitating admission to the hospital. All data were collected on a standardized data collection form and entered into a research database specifically designed for this study. A single research nurse performed all data entry. Patients were routinely monitored from the scene, during transport, and into the emergency center with a Propaq 206 monitor (Welch Allyn, Beaverton, Oregon). The physiologic data used in this study were manually recorded on the run sheet from the screen of the portable monitor. Vital signs, Glasgow Coma Scale score, capillary refill, age, gender, mechanism of injury, and interventions were recorded on the flight charts (see Table II). The most abnormal physiologic data recorded during the flight were used for data analysis. Patients with injuries requiring LSIs were compared with those who did not require LSIs. Prehospital LSIs (P-LSIs) were based on procedures outlined in the Life Flight protocols (Table II). Hospitalbased LSIs (H-LSIs) were determined based on review of all International Classification of Diseases, 9th Revision, Clinical Modification procedure codes entered into the trauma registry for a 12-month sample of admitted trauma patients. Those 306 procedures were then classified as LSIs (153 procedures in 13 major groups) or non-LSIs by a multidisciplinary panel of trauma experts (see Table III).