In 2019, a clinical study realized on 560 patients showed that lung inflation occurred in only 25% of the time when ventilated with a BVM.
The research team from Texas medical Center wondered “Why did so few patients in our study receive ventilation during CPR?”. The study suggests that the rescuers attempted ventilation for each patient, but these attempts frequently did not result in lung inflation.
Ventilation with a BVM device in cardiac arrest patients is a difficult skill to perform properly and bad airway management or poor mask seal might be very hard to recognize.
In this study, patients who had lung inflation in more than 50% of the time had associated improved prehospital ROSC (19.8% vs. 8.7%, p = 0.0009), and survival to hospital discharge (10.3% vs. 4.0%, p = 0.008).
Link to read the clinical study: Association of Ventilation with Outcomes from Out-of-Hospital Cardiac Arrest – PMC (nih.gov)