Hands-off-Zeiten durch AED-Sprachanweisungen

[Effects of automated external defibrillators on hands-off intervals in lay rescuers]

Background

Survival chances after out-of-hospital cardiac arrests caused by hyperdynamic electric cardiac rhythms can be significantly improved by early defibrillation with automated external defibrillators (AEDs). As postulated in international guidelines, the resulting hands-off intervals should not exceed 10 s.

Objectives

We investigated delay in onset of chest compressions and the length of hands-off intervals during defibrillation associated with the application of AEDs.

Materials and methods

In a prospective, randomized, single-blinded observational study, the resuscitation efforts by first year medical students were analyzed in different emergency scenarios on manikins. Delay in onset of chest compressions and the length of hands-off intervals between voice prompts from four conventional devices were compared during shockable and nonshockable rhythms. Satisfaction with the device, difficulties with the application, and suggested improvements were assessed by questionnaire.

Results

In a total of 70 applications, the start with thoracic compressions was delayed by a mean of 115 s. On average, the first shock was administered after 125 s in shockable heart rhythms. Perishock pauses of less than 10 s were achieved with none of the tested devices. Hands-off intervals during defibrillation differed significantly between the devices (p < 0.001). Improvements were suggested regarding marking, voice prompts, and electrodes.

Conclusions

Perishock pause of less than 10 s was not achieved with any of the tested devices. Shortened and more precise voice prompts as well as more clearly arranged labeling and layout of pads are needed to simplify application, reduce delayed onset of chest compressions and shorten hands-off intervals.

Applying Principles From Aviation Safety Investigations to Root Cause Analysis of a Critical Incident During a Simulated Emergency

STATEMENT

Safety investigations in aviation aim to identify potential root causes. They use structured techniques to analyze information from flight data and cockpit voice recorders. Full-scale medical simulations using audiovisual recordings provide similar possibilities. During a simulated cardiac arrest, an incident related to use of the defibrillator (automated external defibrillator) occurred with emergency medical services (EMS) providers. Treatment interventions and dialogs during the incident were extracted from audiovisual recordings and transferred into a transcript of events.Knowing indicated treatment measures, the team adhered to automated external defibrillator voice prompts rather than follow their own assessment. Cardiopulmonary resuscitation was on hold for 72% of the time. Time to first defibrillation was delayed by 2:17 minutes. Transcript allowed us to identify faulty decision-making, loss of leadership, and automation bias as possible root causes. Use of RCA methodology during medical simulation improves understanding of critical incidents and can contribute to training of EMS personnel and education of instructors.