Background: Analgesics, sedatives, and neuromuscular blockers are commonly used medications for mechanically ventilated air medical transport patients. Prior research in the emergency department (ED) and intensive care unit (ICU) has demonstrated that depth of sedation is associated with increased mechanical ventilation duration, delirium, increased hospital length-of-stay (LOS), and decreased survival. The objectives of this study were to evaluate current sedation practices in the prehospital setting and to determine the impact on clinical outcomes. Methods: A retrospective cohort study of mechanically ventilated patients transferred by air ambulance to a single 812-bed Midwestern academic medical center from July 2013 to May 2018 was conducted. Prehospital sedation medications and depth of sedation [Richmond Agitation-Sedation Scale score (RASS)] were measured. Primary outcome was hospital LOS. Secondary outcomes were delirium, length of mechanical ventilation, in-hospital mortality, and need for neurosurgical procedures. Univariate analyses were used to measure the association between sedatives, sedation depth, and clinical outcomes. Multivariable models adjusted for potentially confounding covariates to measure the impact of predictors on clinical outcomes. Results: Three hundred twenty-seven patients were included. Among those patients, 79.2% of patients received sedatives, with 41% of these patients achieving deep sedation (RASS = -4). Among patients receiving sedation, 58.3% received at least one dose of benzodiazepines. Moderate and deep sedation was associated with an increase in LOS of 59% (aRR: 1.59; 95% CI: 1.40-1.81) and 24% (aRR: 1.24; 95% CI: 1.10-1.40), respectively. Benzodiazepines were associated with a mean increase of 2.9 days in the hospital (95% CI, 0.7-5.1). No association existed between either specific medications or depth of sedation and the development of delirium. Conclusions: Prehospital moderate and deep sedation, as well as benzodiazepine administration, is associated with increased hospital LOS. Our findings point toward sedation being a modifiable risk factor and suggest an important need for further research of sedation practices in the prehospital setting.
Keywords: Emergency Medical Services (EMS); air ambulances; deep sedation; delirium; intubation.