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Background Out-of-hospital cardiac arrest (OHCA) data debriefing and clinical research often require the retrospective analysis of large datasets containing defibrillator files from different vendors and clinical annotations by the emergency medical services. Aim To introduce and evaluate a methodology to automatically extract cardiopulmonary resuscitation (CPR) quality data in a uniform and systematic way from OHCA datasets from multiple heterogeneous sources. Methods A dataset of 2236 OHCA cases from multiple defibrillator models and manufacturers was analyzed. Chest compressions were automatically identified using the thoracic impedance and compression depth signals. Device event time-stamps and clinical annotations were used to set the start and end of the analysis interval, and to identify periods with spontaneous circulation. A manual audit of the automatic annotations was conducted and used as gold standard. Chest compression fraction (CCF), rate (CCR) and interruption ratio were computed as CPR quality variables. The unsigned error between the automated procedure and the gold standard was calculated. Results Full-episode median errors below 2% in CCF, 1 min−1 in CCR, and 1.5% in interruption ratio, were measured for all signals and devices. The proportion of cases with large errors ( > 10% in CCF and interruption ratio, and > 10 min−1 in CCR) was below 10%. Errors were lower for shorter sub-intervals of interest, like the airway insertion interval. Conclusions An automated methodology was validated to accurately compute CPR metrics in large and heterogeneous OHCA datasets. Automated processing of defibrillator files and the associated clinical annotations enables the aggregation and analysis of CPR data from multiple sources.

Chest compression (CC) quality is associated with improved out-of-hospital cardiopulmonary arrest (OHCA) outcomes. Airway management efforts may adversely influence CC quality. We sought to compare the effects of initial laryngeal tube (LT) and initial endotracheal intubation (ETI) airway management strategies upon chest compression fraction (CCF), rate and interruptions in the Pragmatic Airway Resuscitation Trial (PART).We analyzed CPR process files collected from adult OHCA enrolled in PART. We used automated signal processing techniques and a graphical user interface to calculate CC quality measures and defined interruptions as pauses in chest compressions longer than 3 s. We determined CC fraction, rate and interruptions (number and total duration) for the entire resuscitation and compared differences between LT and ETI using t-tests. We repeated the analysis stratified by time before, during and after airway insertion as well as by successive 3-min time segments. We also compared CC quality between single vs. multiple airway insertion attempts, as well as between bag-valve-mask (BVM-only) vs. ETI or LT.Of 3004 patients enrolled in PART, CPR process data were available for 1996 (1001 LT, 995 ETI). Mean CPR analysis duration were: LT 22.6 ± 10.8 min vs. ETI 25.3 ± 11.3 min (p 0.001). Mean CC fraction (LT 88% vs. ETI 87%, p = 0.05) and rate (LT 114 vs. ETI 114 compressions per minute (cpm), p = 0.59) were similar between LT and ETI. Median number of CC interruptions were: LT 11 vs. ETI 12 (p = 0.001). Total CC interruption duration was lower for LT than ETI (LT 160 vs. ETI 181 s, p = 0.002); this difference was larger before airway insertion (LT 56 vs. ETI 78 s, p 0.001). There were no differences in CC quality when stratified by 3-min time epochs.In the PART trial, compared with ETI, LT was associated with shorter total CC interruption duration but not other CC quality measures. CC quality may be associated with OHCA airway management.

Introduction: The multicenter Pragmatic Airway Resuscitation Trial (PART) demonstrated better adult out-of-hospital cardiac arrest (OHCA) outcomes with initial laryngeal tube (LT) insertion than endotracheal intubation (ETI) airway management. While emphasized in clinical practice, the effect of advanced airway insertion first-pass success (FPS) upon outcomes after OHCA is unknown. We sought to determine the direct and indirect mediating effects of LT and ETI FPS upon adult OHCA in a secondary analysis of PART. HYPOTHESES: 1) FPS associated with adult OHCA outcomes. 2) FPS mediates (explains) the association between airway type (LT vs. ETI) and adult OHCA outcomes. Methods: We defined FPS as successful LT insertion or ETI on the first attempt as reported by EMS personnel. We examined the outcomes return of spontaneous circulation (ROSC), 72-hour survival, hospital survival, and hospital survival with favorable neurologic function (MRS ≤3). Using multivariable GEE, we determined the association between FPS and outcomes after OHCA, adjusting for age, sex, witnessed arrest status, bystander CPR, initial rhythm, and trial randomization. Using the method of Baron and Kenny, we used mediation analysis to explain the contribution of FPS towards differences in OHCA outcomes between LT and ETI. Results: Of 3,004 patients enrolled in the trial, 1,423 received LT, 1,227 received ETI, 354 received bag-valve-mask ventilation only. FPS was: LT 90.3% and ETI 51.5%. FPS was associated with increased ROSC (adjusted OR 1.36, 95% CI 1.04-1.78) and 72h survival (1.45; 1.20-1.74) but not hospital survival (0.94; 0.67-1.31) or hospital survival with favorable neurologic function (0.70; 0.40-1.23). FPS had a strong mediating effect on the OHCA outcome differences between LT and ETI; 72h survival (74% mediated); ROSC (53% mediated); hospital survival (52% mediated); hospital survival with favorable neurologic status (35% mediated). Conclusion: In adult with OHCA, airway insertion FPS is associated with increased ROSC and 72h survival. Differences in OHCA outcomes between LT and ETI are largely explained by differences in FPS. EMS personnel should emphasize FPS in the advanced airway management of OHCA.