Smartphone apps to support laypersons in bystander CPR are of ambivalent benefit: a controlled trial using medical simulation.

Background: Bystander-initiated resuscitation is essential for surviving out-of-hospital cardiac arrest. Smartphone apps can provide real-time guidance for medical laypersons in these situations. Are these apps a beneficial addition to traditional resuscitation training?

Methods: In this controlled trial, we assessed the impact of app use on the quality of resuscitation (hands-off time, assessment of the patient's condition, quality of chest compression, body and arm positioning). Pupils who have previously undergone a standardised resuscitation training, encountered a simulated cardiac arrest either (i) without an app (control group); (ii) with facultative app usage; or (iii) with mandatory app usage. Measurements were compared using generalised linear regression.

Results: 200 pupils attended this study with 74 pupils in control group, 65 in facultative group and 61 in mandatory group. Participants who had to use the app significantly delayed the check for breathing, call for help, and first compression, leading to longer total hands-off time. Hands-off time during chest compression did not differ significantly. The percentage of correct compression rate and correct compression depth was significantly higher when app use was mandatory. Assessment of the patient's condition, and body and arm positioning did not differ.

Conclusions: Smartphone apps offering real-time guidance in resuscitation can improve the quality of chest compression but may also delay the start of resuscitation. Provided that the app gives easy-to-implement, guideline-compliant instructions and that the user is familiar with its operation, we recommend smartphone-guidance as an additional tool to hands-on CPR-training to increase the prevalence and quality of bystander-initiated CPR.