When Bystanders Skip CPR: Insights from a Retrospective Study

Background and Objectives: Out-of-hospital cardiac arrest (OHCA) is one of the most clinically significant conditions and can lead to rapid death if cardiopulmonary resuscitation (CPR) or defibrillator use is not performed. Despite this, in approximately half of cases of witnessed OHCA, bystanders do not initiate resuscitation maneuvers. The factors underlying this phenomenon are varied but not yet fully understood. The aim of our analysis is to identify predictors that may indicate a higher likelihood of not performing resuscitation maneuvers. Materials and Methods: Data from cardiac arrests managed by the emergency medical system of the Lombardy region between 1 July 2024 and 30 June 2025 were analyzed. All missions involving cardiac arrests assisted only by lay bystanders were included in the analysis. Results: A total of 12,066 events were analyzed, of which only 4233 were assisted by laypeople. According to the logistic regression model, cardiac arrests occurring in urban settings (OR 0.60; 95% CI: 0.51-0.71), non-medical events (OR 0.44; 95% CI: 0.37-0.51), female patients (OR 0.80; 95% CI: 0.70-0.91), patients over 80 years old (OR 0.40; 95% CI: 0.35-0.45), and events occurring at home (OR 0.33; 95% CI: 0.28-0.39) were associated with a lower likelihood of performing chest compressions. Conversely, when the emergency service arrived within 15 min (OR 1.31; 95% CI: 1.14-1.51), the probability of receiving chest compressions increased. Conclusions: The presence of such a significant gap related to age and sex is noteworthy, prompting greater attention to the educational material presented during BLS-D courses. Moreover, these factors should be considered by the dispatch center when providing pre-arrival instructions to laypeople for initiating chest compressions. Specific communication training should be developed, and communication in these critical phases should be the subject of further study.