Timing of termination of non-traumatic cardiopulmonary resuscitation in out-of-of hospital setting based on myocardial movements on cardiac ultrasound - analysis from a real-world case report database

Abstract

The European Resuscitation Council Guidelines 2025 for Adult Advanced Life Support (ALS) warn against the use of point-of-care ultrasound (PoCUS) for assessing contractility of the myocardium as a sole indicator for terminating cardiopulmonary resuscitation (CPR). Clinical research in this regard is hampered by significant indication bias. This study aimed to analyse the real-life use of PoCUS during out-of-hospital non-traumatic CPR cases and examine the relationship between the myocardial contractility and the timing of termination of the unsuccessful resuscitation. 1,812 non-traumatic CPR cases were analysed from the structured database of the HEMS digital case reports between 2019 and 2024, excluding 42 patients transferred with continuous CPR. Intra-arrest cardiac ultrasound was performed based on the HEMS-Doctor’s decision, based on experience and potential reversible causes of CPR. Baseline demographic and clinical information was collected, as well as data on intra-arrest myocardial movements. The duration of the ALS was given in minutes from the (estimated) time of the cardiac arrest, until the permanent return of spontaneous circulation (RoSC), or the decision to terminate the unsuccessful resuscitation. The continuous variables were compared between groups using Kaplan-Meier analysis. Jamovi ver. 2.6. and R version 4.4. were used for graphical interpretation and statistical analysis. From the 1,770 cases, 334 (18.9%) survived to hospital admission. Notably, 236 patients achieved RoSC before cardiac ultrasound was performed, with an ALS duration of median 12 minutes (IQR 6-25). For pseudo-PEA cases (n=139), the median of ALS duration was 35 minutes (95% CI 32-39). Log-rank test comparisons indicated no significant duration differences between the cardiac standstill (n=877) and no-ultrasound (n=692) groups [23 minutes (95% CI 22-24) vs. 21 minutes (95% CI 20-23), p=0.988], but both groups differed significantly from the pseudo-PEA group (p<0.001). Focusing solely on the duration of unsuccessful resuscitations to analyse decision-making, the ALS duration median for pseudo-PEA cases (n=89) was 31 minutes (95% CI 30-35), for cardiac standstill cases (n=828) was 23 minutes (95% CI 22-24), and for no ultrasound cases (n=456) was 18 minutes (95% CI 18-20), Log-rank tests indicated significant differences in all pairwise comparisons (p<0.001). During prolonged resuscitation, visible myocardial movements (pseudo-PEA) may lead to further continuation of resuscitation efforts. However, the duration of unsuccessful CPR attempts in cardiac standstill patients may not be shorter than in those without intra-arrest ultrasound. Thus, recognizing cardiac standstill may not lead to earlier CPR termination compared to traditional clinical decision-making. Further studies are essential to assess how intra-arrest ultrasound can improve patient outcomes and clinical decision-making.Kaplan-Meier curves