Background
Extracorporeal cardiopulmonary resuscitation (ECPR) is increasingly used in patients with out‐of‐hospital or in‐hospital cardiac arrest in whom conventional cardiopulmonary resuscitation remains unsuccessful. The aim of this study was to analyze the impact of initial cardiac rhythm—detected on‐site of the cardiac arrest—on mortality.
Methods
We performed a retrospective cohort study of patients who received ECPR in our tertiary care cardiac arrest center. Patients were divided into three groups depending on their cardiac rhythm: shockable rhythm, pulseless electrical activity, and asystole. The primary endpoint was mortality within the first 7 days after ECPR deployment. Secondary endpoints were mortality within 28 days and the impact of pre‐ECPR potassium, serum lactate, pH, and pCO2 on mortality. The association of the initial cardiac rhythm and the location of arrhythmia detection (patient monitored in hospital [category: monitored], not monitored but hospitalized [in‐hospital], not monitored, not hospitalized [out‐of hospital]) with the primary and secondary outcome was examined by means of univariable and multivariable logistic regression.
Results
Sixty‐five patients could be included in the final analysis. Thirty‐two patients (49.2%, 95%CI 36.6%–61.9%) died within the first 7 days. In terms of 7‐day‐mortality patients differed in the initial cardiac rhythm (p = 0.040) and with respect to the location of arrhythmia detection (p = 0.002). Shockable cardiac rhythm (crude OR 0.21; 95%CI 0.03–0.98) and pulseless electrical activity (0.13; 0.02–0.61) as the initial rhythm on‐site showed better odds for survival compared to asystole. However, this association did neither persist in adjusted analysis nor pairwise comparison.
Discussion
The study could not demonstrate a better outcome with shockable rhythm after ECPR. More homogeneous and adequately powered cohorts are needed to better understand the impact of cardiac rhythm on patient outcomes after ECPR.