The Prehospital Use of External Counterpressure

Abstract

Military antishock trousers (MAST) have achieved widespread civilian usage because of reported effectiveness in treating hypovolemic shock. The literature, however, consists of either case reports or series in which no controls were evaluated. No published reports exist which compare similar groups of patients treated with and without MAST in the pre-hospital setting. The paramedic and emergency department records of 226 patients sustaining moderate to severe trauma who were transported to San Francisco General Hospital by paramedics over a 15 mo. period were reviewed. MAST usage during this period was approximately random as a result of logistical and training constraints. For analysis, patients were divided into 2 groups: those in whom MAST was applied and inflated during transport and those in whom it was not used. Paramedic interventions other than MAST were similar in both groups. Trauma Scores (TS), and blood pressure index (> 90 = 4, 70-89 = 3, 50-69 = 2, 0-49 = 1, no pulse = 0), were calculated for initial field observations and initial emergency room evaluation after hospital arrival. Patients with isolated head injury were excluded. The average change in TS and BP index (E.R.-field value) was calculated for MAST and non-MAST groups of patients. Mortality and total field times were also evaluated. Average TS and BP index increased slightly in both groups. Use of MAST produced no significant inprovement in trauma score, BP index, or mortality over non-MAST patients. There was no demonstrable field benefit of MAST in fully arrested patients. The field application of MAST did not delay transport as similar field times were observed in MAST and non-MAST groups. While the observed increases in TS and BP index in MAST patients are consistent with previous reports, there appears to be no advantage to using MAST in addition to conventional in-field treatment. The expense and extra training required for MAST utilization may not be justified in an urban setting with short transport times. Prospective randomized studies are clearly needed to establish its proper role or non-role in trauma management.