The effect of urban trauma system hospital bypass on prehospital transport times and Level 1 trauma patient survival.

We studied the influence of hospital bypass on prehospital times and Level 1 trauma patient survival. During the nine-month study period, 251 Level 1 trauma patients were transported to the Cook County Hospital trauma unit by Chicago Fire Department (CFD) paramedics. The prehospital times and survival rates in the 203 (81%) patients who arrived with vital signs were analyzed. In this group, 64 (32%) had a hospital Trauma Score (TS) of 12 or less, 74 (39%) had at least one Abbreviated Injury Score (AIS) of 4 or more, and 58 (30%) had an Injury Severity Score (ISS) of more than 20. There were 66 (32%) directly transported patients and 137 (68%) patients who required hospital bypass. The time from CFD contact (by 911) to trauma center arrival (total run time) was on the average three minutes longer in the bypass group than in the direct group (36 +/- 11 vs 33 +/- 10 minutes, P less than .05). The travel time from the scene to the hospital (transport time) also was three minutes longer in the bypass group (7 +/- 3 vs 4 +/- 2 minutes, P less than .005). The need for bypass did not significantly influence survival. Survival was 86% in the bypass group and 85% in the direct group. The elapsed time between the injury and CFD contact (delay time) averaged 27 +/- 26 minutes and contributed 43% to the 63-minute mean overall time from the injury event to arrival at the trauma center. Total run time in directly transported patients accounted for 52% of the mean overall prehospital time.(ABSTRACT TRUNCATED AT 250 WORDS)