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 < .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 < .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. The additional three minutes required to divert bypass patients to the trauma center (bypass time) added only 5% to the overall prehospital time. We conclude that the urban use of hospital bypass does not decrease trauma patient survival in those who arrive at the trauma center with vital signs. We also conclude that attempts should be made to shorten delay in CFD contact to reduce overall prehospital time and maximize patient survival. Further study in both urban and rural settings should determine whether bypass allows death to occur during transport and whether longer bypass times influence overall prehospital time and mortality.