Electrifying Insights: Study Unraveling the Impact of Defibrillator Types on Resuscitation Success

In recently published study, the association between manual defibrillator and automated external defibrillator (AED) usage was analyzed during in-hospital cardiac arrests (IHCA), focusing on rhythm analysis accuracy, chest compression pause durations, and return of organized rhythms. Data was obtained from a multicenter historical cohort study involving one university hospital and four regional hospitals in Denmark from April 2019 to March 2024, covering approximately 1.3 million people.

Rhythm Analysis Accuracy

Return of organized rhythms was defined as having an organized rhythm post-defibrillation, with exclusion criteria for certain inappropriate shocks. The primary outcome measured was the accuracy of rhythm analyses, categorized by rhythm types (ventricular fibrillation (VF), ventricular tachycardia (VT), pulseless electrical activity (PEA), and asystole). The study found accurately classified rhythm analyses in 95.1% of cases, where AEDs showed slightly superior accuracy (100% sensitivity, 96.5% specificity) compared to manual defibrillators (sensitivity 78.4%, specificity 96.2%). Overall, the adjusted odds ratio for accurate rhythm analysis using manual defibrillators was significantly lower at 0.5 compared to AEDs. Secondary outcomes emphasized pause durations. Manual defibrillators demonstrated shorter median pause durations during rhythm analyses (3.2 seconds shorter) and shorter peri-shock pauses (7.9 seconds shorter). These shorter pauses correlate with improved survival outcomes, aligning with previous studies displaying the critical impact of minimizing pause durations during resuscitation attempts. Despite demonstrating increased pause efficiency, manual defibrillators were associated with a lower proportion of return of organized rhythms (67.8%) compared to AEDs (42.5%). After adjusting for confounding factors, the odds ratio for return of organized rhythms with manual defibrillators was 0.6. This suggests manual defibrillators, although more efficient regarding pause durations, may not facilitate the transition to organized rhythms as effectively as AEDs, potentially due to varying usage contexts and patient characteristics.

Study Limitations

Limitations of the study included the observational design, which introduces potential selection bias and uncontrolled confounding. The study's reliance on available defibrillator data and the inability to record specific reasons for interruptions during rhythm analyses further complicates the findings.

Conclusions and Implications

The study underscores that while manual defibrillators provide logistical advantages in terms of pause durations, AEDs can have superior outcomes in establishing organized rhythms, suggesting that AEDs should remain integral in initial IHCA responses, alongside further optimization of manual defibrillator use. Additionally, the enhancements and updates made after acceptance, including formatting adjustments, do not influence the study's findings but ensure readability, adhering to legal disclaimers and pending a definitive version during production.

Key Points

- -Study Design and Sample-: The analysis was conducted as a multicenter historical cohort study across one university hospital and four regional hospitals in Denmark, encompassing data from April 2019 to March 2024, covering a population of approximately 1.3 million individuals experiencing in-hospital cardiac arrests (IHCA).

- -Rhythm Analysis Accuracy-: Returned organized rhythms were evaluated post-defibrillation, with accurate rhythm classifications achieved in 95.1% of cases. Automated external defibrillators (AEDs) demonstrated superior rhythm analysis accuracy compared to manual defibrillators, achieving 100% sensitivity and 96.5% specificity versus 78.4% sensitivity and 96.2% specificity for manual devices. An adjusted odds ratio of 0.5 indicated significantly lower odds of accurate rhythm analysis with manual defibrillators.

- -Chest Compression Pause Durations-: Manual defibrillators exhibited shorter median pause durations both during rhythm analyses (3.2 seconds shorter) and peri-shock pauses (7.9 seconds shorter). These findings align with the established understanding that minimized pause durations are critical for improved survival rates during resuscitation.

- -Return of Organized Rhythms-: Despite the efficiency in pause durations, manual defibrillators were linked to a lower rate of return of organized rhythms (67.8%) when compared to AEDs (42.5%). An adjusted odds ratio of 0.6 suggests that while manual devices may shorten intervention pauses, they do not facilitate a similar transition to organized rhythms in relevant patient populations.

- -Limitations of the Study-: Several limitations were identified, including the observational study design which raises concerns regarding potential selection bias and uncontrolled confounding factors. Additionally, the analysis relied on available data from defibrillators without capturing the specific causes for interruptions during rhythm assessments.

- -Clinical Implications-: Although manual defibrillators enhance logistical aspects of pause durations, the findings advocate for the continued use of AEDs as a primary response in IHCA situations due to their superior ability to achieve organized rhythms. Recommendations include further refinement of manual defibrillator usage while acknowledging the need to integrate AEDs effectively in resuscitation protocols.

Reference –

Moritz Nettinger et al. (2025). Associations Of Manual Defibrillator Compared To Automated External Defibrillator Usage With Defibrillation And Resuscitation Quality During In-Hospital Cardiac Arrest.. *Resuscitation*, 110619 . https://doi.org/10.1016/j.resuscitation.2025.110619.