ABSTRACTS
Optimal Weight-based Epinephrine Dosing for Patients with Low Likelihood of Survival Following Out-of-Hospital Cardiac ArrestAuthor: Michael W. Hubble, PhD, MBA, NRP | | Associate Authors: Ginny K. Renkiewicz, PhD, Melisa D. Martin, EdD, MHS
Introduction Patients presenting with nonshockable rhythms during out-of-hospital cardiac arrest (OHCA) have a low probability of survival, and epinephrine is one of the few resuscitative options. The recommended adult dose of epinephrine is 1 mg every 3–5 minutes. This dosing recommendation is extrapolated from early animal studies, is largely based on expert opinion, and lacks adjustment for differences in patient weight. Although some prior studies have investigated “low-dose” and “high-dose” epinephrine, none have identified a clear benefit to either dosing strategy. Subsequently, the optimal dose of epinephrine remains elusive. Objective To identify an optimal weight-based epinephrine dose for attaining return of spontaneous circulation (ROSC) among patients most likely to benefit from epinephrine during OHCA. Methods This retrospective study included adult patients from a national EMS electronic health record vendor who experienced witnessed, nontraumatic OHCA prior to EMS arrival from January 2020 through December 2020. To focus on patients for whom epinephrine offers the greatest potential benefit, we excluded patients with shockable presenting rhythms and bystander CPR. The area under the receiver operator characteristic curve (AUROC) was used to assess the predictive value of epinephrine dose (mg/kg) for ROSC following a single bolus. From the ROC curve values, the optimal threshold dosage for ROSC was determined based on the concordance probability method. Results A total of 2,463 patients met inclusion criteria and had complete data for analysis. Males accounted for 61.3% of the sample, and 29.5% were minorities. The mean age of participants was 66.7 (±15.9 SD) years with a mean weight of 91.2 kg (±31.5 SD). Arrest etiologies included cardiac (80.6%), respiratory/asphyxia (13.2%), overdose (2.7%), and other (3.5%). A total of 190 patients (7.7%) attained ROSC after the first epinephrine administration. The mean dose (mg/kg) was higher in the group attaining ROSC (0.0136 vs. 0.0121, p < 0.001). The dosage AUROC for ROSC was 0.61 (p < 0.01). As calculated by the concordance probability method, the optimal threshold first epinephrine dosage was 0.013 mg/kg. Conclusions Among patients in our dataset with a low likelihood of survival, the optimal dose of epinephrine for attaining ROSC was 0.013 mg/kg. These findings should inspire further investigation into optimal dosing strategies for epinephrine.
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