The AIR-SED Study: A Multicenter Cohort Study of SEDation Practices, Deep Sedation, and Coma Among Mechanically Ventilated AIR Transport Patients

Objectives: To characterize prehospital air medical transport sedation practices and test the hypothesis that modifiable variables related to the monitoring and delivery of analgesia and sedation are associated with prehospital deep sedation.

Design: Multicenter, retrospective cohort study.

Setting: A nationwide, multicenter (approximately 130 bases) air medical transport provider.

Patients: Consecutive, adult mechanically ventilated air medical transport patients treated in the prehospital environment (January 2015 to December 2020).

Interventions: None.

Measurements and main results: All data involving sedation (medications, monitoring) were recorded. Deep sedation was defined as: 1) Richmond Agitation-Sedation Scale of -3 to -5; 2) Ramsay Sedation Scale of 5 or 6; or 3) Glasgow Coma Scale of less than or equal to 9. Coma was defined as being unresponsive and based on median sedation depth: 1) Richmond Agitation-Sedation Scale of -5; 2) Ramsay of 6; or 3) Glasgow Coma Scale of 3. A total of 72,148 patients were studied. Prehospital deep sedation was observed in 63,478 patients (88.0%), and coma occurred in 42,483 patients (58.9%). Deeply sedated patients received neuromuscular blockers more frequently and were less likely to have sedation depth documented with a validated sedation depth scale (i.e., Ramsay or Richmond Agitation-Sedation Scale). After adjusting for covariates, a multivariable logistic regression model demonstrated that the use of longer-acting neuromuscular blockers (i.e., rocuronium and vecuronium) was an independent predictor of deep sedation (adjusted odds ratio, 1.28; 95% CI, 1.22-1.35; p < 0.001), while use of a validated sedation scale was associated with a lower odds of deep sedation (adjusted odds ratio, 0.29; 95% CI, 0.27-0.30; p < 0.001).

Conclusions: Deep sedation (and coma) is very common in mechanically ventilated air transport patients and associated with modifiable variables related to the monitoring and delivery of analgesia and sedation. Sedation practices in the prehospital arena and associated clinical outcomes are in need of further investigation.