Lights and Siren Transport and the Need for Hospital Intervention in Trauma Patients

Emergent ambulance transportation is associated with increased risk of collision, injury, and death for EMS professionals, patients, and the general public. Time saved using lights and siren (L&S) is typically small, and often provides minimal clinical benefit. Our objective was to investigate the frequency of L&S transports, describe the precision of the decision to employ L&S to predict the need for a time critical hospital intervention (TCHI) within 15 minutes of hospital arrival, identify clinical predictors of a TCHI, and compare clinical outcomes in patients transported by Emergency Medical Services (EMS) with and without L&S in a trauma-specific population. EMS patient care reports and trauma registry data were retrospectively reviewed for trauma patients consecutively transported from the field by three EMS agencies to three trauma centers within urban and suburban settings over a two-year period. TCHIs were collaboratively developed by the study team. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were utilized to report the precision of the decision to employ L&S to predict the need of a TCHI. Univariate and multivariate analyses determined predictors of a TCHI and compared clinical outcomes. 2,091 patients were included in the study. Of the 19.8% of patients transported with L&S, 22.9% received a TCHI. The most common TCHI was airway or respiratory procedures (87.2% of all TCHI's). The sensitivity and specificity of L&S to predict the need for a TCHI was 87.2% (95% CI 79.4-92.8) and 84.0% (95% CI 82.2-85.5), respectively. PPV was 23.0% (95% CI 23.53-38.01); NPV was 99.2% (95% CI 98.6-99.6). L&S was predictive for the need for a TCHI (p < 0.001), as was abnormal Glasgow Coma Score (p < 0.001), abnormal systolic blood pressure and age (p < 0.05 for all). Among patients that received a TCHI, over a third that were transported with L&S (36.8%) expired, compared with two of 14 patients (14.3%) not transported L&S. EMS professionals in this study demonstrated a high ability to discern which trauma patients did not require L&S. Nevertheless, L&S transport resulted in a TCHI less than one quarter of the time, suggesting an opportunity for further reduction of L&S transports in trauma patients.