Hospital-based helicopter services from German and American university-affiliated trauma centers were reviewed. All multitrauma patients transported via helicopter from the scene of the accident to the trauma center during a 1-year period were included. The patients were comparable regarding mechanism of injury, age, flight times, mean ISS, ISS distribution, and number of severe injuries per body region (patients with AIS > 3 for head, thorax and abdomen). Overall mortality for the German system was 21/221 (9.5%) and 21/186 (11.3%) for the American system (not significant). Survivor-based TRISS analysis yielded Z-statistics of +2.459 for the German, and +1.049 for the American system. There were 9 unexpected survivors (Ps < 0.5) in the German, 6 in the American system. There was a significant higher (P < 0.01) number of early deaths (< 6 h) in the American population (12, ISS 56) than in the German (4, ISS 64). Analysis of the prehospital data demonstrated significant differences in the mean volume of IV fluids infused: 1800 cc German, 825 cc American (P < 0.05); rate of intubation: 82/221 (37.1%) German, 24/186 (13.4%) American (P < 0.001); and thoracic decompressions: 20/221 (9.1%) German, 1/186 (0.5%) American (P < 0.001). Pre-hospital care in the German system is directed on-scene by a trauma surgeon member of the flight crew, compared to a nurse/paramedic team with remote medical control in the American system. Compared to an American trauma system, the German system demonstrates improved overall outcome as measured by survivor-based TRISS Z-statistics. More favorable German Z-statistics are in part related to fewer early deaths.(ABSTRACT TRUNCATED AT 250 WORDS)