Clinical trials of the pneumatic antishock garment in the urban prehospital setting

As a result of experimental data and favorable clinical impressions, the pneumatic antishock garment (PASG) has gained widespread acceptance as a reasonable standard of care in emergency medical services (EMS) systems. It is currently legislated as required equipment for medical rescue vehicles in two-thirds of the United States. But despite a decade of widespread use, prospective, randomized, controlled trials that demonstrate the efficacy of the PASG have not been published. Furthermore, certain complications have been reported and concerns have been raised about the use of the PASG under certain circumstances, such as penetrating thoracic injury. In the fall of 1983, the City of Houston EMS system embarked on a long-term prospective evaluation of PASG use in hypotensive victims of injury in the urban prehospital setting. All victims of injury whose systolic blood pressure was 90 mm Hg or less when they initially presented to paramedics in the field were entered into the study. All patients received the identical treatment protocol, with the sole exception of PASG application and inflation to full pressure prior to intravenous catheterization on an alternate day basis. Prospectively collected demographic data have demonstrated that the two resulting groups of PASG and no-PASG patients are well matched in terms of age, sex, injury type, anatomic location of the injury, initial field trauma score, injury, severity score and probabilities of survival, as well as the amounts of IV fluids infused in the prehospital setting and the response, scene, and transport times. The groups remain well matched even when specific subgroups have been examined, such as those with penetrating abdominal injuries or those with systemic blood pressures less than 70 mm Hg. Overall the PASG has offered no advantage in terms of survival, morbidity, or hospital costs. In the subset of patients with primary truncal injury (and no concurrent head injury) whose initial blood pressure was 70 mm Hg on field encounter (n = 74), there were no significant differences in survival in the PASG (26 of 37) and control (27 of 37) groups. Similarly there were no significant differences in survival in 175 patients with penetrating abdominal wounds and 152 patients with penetrating thoracic wounds. Compartment syndromes were observed in three patients who had no underlying extremity injury. It has been concluded that use of the PASG in hypotensive penetrating trauma victims offers no specific advantage in an urban paramedic-regional trauma center system that is closely scrutinized in the prehospital setting by full-time physician supervision and that emphasizes rapid response and evacuation along with aggressive prehospital airway management and immediate in-hospital surgical intervention. Further studies evaluating the PASG in other settings and for other types of injuries are strongly recommended. Medical devices should be subject to close scientific scrutiny prior to widespread marketing and unrestricted use in patients.