The impact of aggressive out-of-hospital management on disposition for 1286 patients with closed head injuries in ground advanced life support (ALS) and helicopter services was evaluated over 60 months in San Diego County. The case group included 196 air medical patients with a scene Glascow coma scale (GCS) < 9 who were treated according to a standard head injury protocol. The frequency matched control group included 1090 ground ALS patients receiving airway management with hyperventilation but neither induction agents nor mannitol. The trauma registry provided admission and discharge dates, neurosurgical interventions, and disposition. Patient age, scene GCS, head and neck abbreviated injury scale (HNAIS), and injury severity score (ISS) served to stratify study groups. Case-control distribution of mortality was compared with the two-tailed Mantel-Haenszel weighted odds ratio (OR) and chisquared test; significance at P < or = 0.05. The case group displayed an 11% decreased mortality (P < 0.01), remaining significant after adjusting for age (P = 0.05) and scene GCS (P = 0.06). The case group displayed 10% (P < 0.01) greater survivor discharges to rehabilitation and 6% (P < 0.05) fewer discharges to extended care facilities. This study's data indicate a strong possibility for improved patient morbidity and mortality in severe closed head injuries treated with an aggressive treatment protocol and rapid air medical transport.