Bolus Dose Epinephrine Improves Blood Pressure but is Associated with Increased Mortality in Critical Care Transport.

Hypotension in the prehospital environment is common and linked to dose-dependent mortality. Bolus dose epinephrine (BDE) may reverse hypotension. We tested if BDE use to treat profound hypotension is associated with 24-hour survival. We performed a retrospective case-cohort study of critical care transport patients with systolic blood pressure (SBP) <70 mmHg from January 2011 to January 2017. To account for baseline differences between treated and untreated patients, we used nearest neighbor matching to estimate the average treatment effect of BDE on 24-hour survival. Included covariates were age, gender, shock type (cardiogenic, distributive, obstructive or hypovolemic), weight, type of service, vitals (heart rate, SBP and diastolic blood pressure, respiratory rate, oxygen saturation, end-tidal carbon dioxide, and Glasgow Coma Scale score) at the time of the first hypotensive episode, as well as pretreatment characteristics including cardiopulmonary resuscitation, defibrillation, transcutaneous pacing, needle thoracostomy, vasopressors, intubation, or arrhythmias. After statistical analysis, we assessed for residual bias by selecting random matched patient records and asking 2 blinded physicians to rate overall illness severity on a Likert scale. We compared perceived illness severity between cases and matched controls using a rank-sum test. There were 6,992 patients transported with SBP <70 mmHg at least once and 4,374 meet inclusion criteria. Of the 1,620 patients transported after protocol implementation, 574 (35%) received BDE. Overall 24-hour survival, survival to discharge and 30-day survival were 80, 57, and 54%, respectively. Survival at 24 hours differed between the BDE group (66%) and controls (82%). These differences persisted at both discharge and 30 days. Administration of BDE was associated with increased post-treatment SBP. BDE treated patients were also more likely to receive cardiopulmonary resuscitation and vasopressors after treatment than untreated hypotensive patients, but there was no association with tachydysrhythmias requiring defibrillation. Bolus dose epinephrine increases blood pressure in the prehospital setting. Despite robust efforts to control for confounding, BDE remained associated with increased mortality in this observational cohort. This association may be due to unmeasured confounding and a randomized controlled trial is necessary to establish a causal relationship between bolus dose vasopressors and mortality.