Chest compressions have been suggested to provide passive ventilation during cardiopulmonary resuscitation. Measurements of this passive ventilatory mechanism have only been performed upon arrival of out-of-hospital cardiac arrest patients in the emergency department. Lung and thoracic characteristics rapidly change following cardiac arrest, possibly limiting the effectiveness of this mechanism after prolonged resuscitation efforts. Goal of this study was to quantify passive inspiratory tidal volumes generated by manual chest compression during prehospital cardiopulmonary resuscitation.

A flowsensor was used during adult out-of-hospital cardiac arrest cases attended by a prehospital medical team. Adult, endotracheally intubated, non-traumatic cardiac arrest patients were eligible for inclusion. Immediately following intubation, the sensor was connected to the endotracheal tube. The passive inspiratory tidal volumes generated by the first thirty manual chest compressions performed following intubation (without simultaneous manual ventilation) were calculated.

10 patients (5 female) were included, median age was 64 years (IQR 56, 77 years). The median compression frequency was 111 compression per minute (IQR 107, 116 compressions per minute). The median compression depth was 5.6 cm (IQR 5.4 cm, 6.1 cm). The median inspiratory tidal volume generated by manual chest compressions was 20 mL (IQR 13, 28 mL).

Using a flowsensor, passive inspiratory tidal volumes generated by manual chest compressions during prehospital cardiopulmonary resuscitation, were quantified. Chest compressions alone appear unable to provide adequate alveolar ventilation during prehospital treatment of cardiac arrest.