Early administration of epinephrine (adrenaline) in patients with cardiac arrest with initial shockable rhythm in hospital: propensity score matched analysis

Abstract

Objectives: To evaluate whether patients who experience cardiac arrest in hospital receive epinephrine (adrenaline) within the two minutes after the first defibrillation (contrary to American Heart Association guidelines) and to evaluate the association between early administration of epinephrine and outcomes in this population.

Design: Prospective observational cohort study.

Setting: Analysis of data from the Get With The Guidelines-Resuscitation registry, which includes data from more than 300 hospitals in the United States.

Participants: Adults in hospital who experienced cardiac arrest with an initial shockable rhythm, including patients who had a first defibrillation within two minutes of the cardiac arrest and who remained in a shockable rhythm after defibrillation.

Intervention: Epinephrine given within two minutes after the first defibrillation.

Main outcome measures: Survival to hospital discharge. Secondary outcomes included return of spontaneous circulation and survival to hospital discharge with a good functional outcome. A propensity score was calculated for the receipt of epinephrine within two minutes after the first defibrillation, based on multiple characteristics of patients, events, and hospitals. Patients who received epinephrine at either zero, one, or two minutes after the first defibrillation were then matched on the propensity score with patients who were "at risk" of receiving epinephrine within the same minute but who did not receive it.

Results: 2978 patients were matched on the propensity score, and the groups were well balanced. 1510 (51%) patients received epinephrine within two minutes after the first defibrillation, which is contrary to current American Heart Association guidelines. Epinephrine given within the first two minutes after the first defibrillation was associated with decreased odds of survival in the propensity score matched analysis (odds ratio 0.70, 95% confidence interval 0.59 to 0.82; P<0.001). Early epinephrine administration was also associated with a decreased odds of return of spontaneous circulation (0.71, 0.60 to 0.83; P<0.001) and good functional outcome (0.69, 0.58 to 0.83; P<0.001).

Conclusion: Half of patients with a persistent shockable rhythm received epinephrine within two minutes after the first defibrillation, contrary to current American Heart Association guidelines. The receipt of epinephrine within two minutes after the first defibrillation was associated with decreased odds of survival to hospital discharge as well as decreased odds of return of spontaneous circulation and survival to hospital discharge with a good functional outcome.

Fig 1 Inclusion and exclusion of patients in study of timing of administration of epinephrine for inpatients with cardiac arrest. Out of 3777 patients who met all inclusion criteria, 2974 were included in main cohort

Fig 2 Distribution of timing of epinephrine in relation to first defibrillation. 692 (23%) patients did not receive epinephrine at any time during resuscitation and 1510 (51%) received epinephrine within two minutes after first defibrillation

Fig 3 Proportion of patients with early administration (within two minutes after defibrillation) of epinephrine per year, showing significant increase over time in both bivariable and multivariable analysis (both P=0.001 for linear trends)

Fig 4 Graphical representation of odds ratios in propensity matched cohort for outcomes survival, return of spontaneous circulation (ROSC), and good functional outcome epinephrine administration compared with no epinephrine administration ≤2 min after first defibrillation. Error bars represent 95% confidence intervals