Optimal Duration and Timing of Basic-life-support-Only Intervention for Patients with Out-of-Hospital Cardiac Arrest: A Nationwide Observational Study in Japan

Abstract

Abstract Aim: The study aimed to elucidate the relationship between the interval from cardiopulmonary resuscitation (CPR) initiation to return of spontaneous circulation (ROSC) and neurologically favourable 1-month survival in order to determine the appropriate duration of basic life support (BLS) without advanced interventions. Methods: This retrospective, population-based cohort study included patients aged ≥ 18 years with 9,132 out-of-hospital cardiac arrest (OHCA) of presumed cardiac origin who were bystander-witnessed and had achieved ROSC between 2018 and 2020 in Japan. Patients were classified into two groups based on the resuscitation methods as the “BLS-only group” and the “BLS with administered adrenaline (BLS-AA) group”. Results: Receiver operating characteristic (ROC) curve analysis indicated that administering BLS for 9 min yielded the best neurologically outcome for patients with a shockable initial rhythm [sensitivity, 0.42; specificity, 0.27; area under the ROC curve (AUC), 0.60] in the BLS-only group. Contrastingly, for patients with a non-shockable initial rhythm, performing BLS for 6 min yielded the best neurologically outcome (sensitivity, 0.65; specificity, 0.43; AUC, 0.63). Among patients who received adrenaline, administering BLS for 15 min yielded the best neurologically outcome for patients with shockable (sensitivity, 0.52; specificity, 0.30; AUC, 0.64) and non-shockable (sensitivity, 0.61; specificity, 0.31; AUC, 0.68) rhythms. Based on the ROC curve analysis results, we defined early ROSC achievement as within 9 min and 6 min for patients with shockable and non-shockable rhythms, respectively. Multivariate analysis indicated that BLS-only resuscitation had the most significant impact on early ROSC achievement in patients with shockable [odds ratio; 95% confidence interval): 9.98 (8.25–12.07) and non-shockable [28.97 (23.10–36.34)] rhythms. After propensity score matching, multivariate analysis revealed that neurologically favourable 1-month survival was associated with BLS-only resuscitation [5.00 (4.08–6.13)], night-time events [1.29 (1.03–1.62)], patient age [0.95 (0.94–0.96)], male sex [1.45 (1.16–1.81)], bystander CPR [1.55 (1.28–1.87)], initial shockable rhythms [3.21 (2.64–3.91)], transportation to level-3 hospitals [1.65 (1.37–1.98)], CPR-to-ROSC interval [0.96 (0.95–0.98)], and on-scene time [0.97 (0.95–0.99)]. Conclusion: Our findings suggest that paramedics should provide concentrated and high-quality chest compressions within the first few minutes of scene arrival prior to administering advanced interventions.