When a patient suffers an out-of-hospital cardiac arrest, ventilation and chest compressions are often given simultaneously during cardiopulmonary resuscitation. These simultaneous chest compressions may cause a fragmentation of the airflow, which may lead to an ineffective ventilation. This study focusses on the occurrence and quantification of this fragmentation and its effect on ventilation.

This study is a single-center observational study, held at Ghent University Hospital. A custom-built bidirectional flow sensor was used to quantify the volumes of ventilation. Adult cardiac arrest patients who were prehospitally intubated and resuscitated by the medical emergency team were eligible for inclusion. Data of the patients who were ventilated and received simultaneous chest compressions, was used to calculate the volumes of ventilation and the amount and volumes of fragmentation. All data in this study is reported as mean (standard deviation; range).

Data of 10 patients (7 male) with a mean age of 71 years (14;51–87) was used in this study. The mean ventilation frequency was 12/min (2;9–16), the mean minute volume and tidal volume were respectively 6.21 L (1.51;3.79–8.15) and 514 mL (99;422–682). Fragmentation of the airflow was observed in all patients, with an average of 3 (1;2–5) fragments per inspiration and a mean volume of 214 mL (65;112–341) per fragment.

Chest compressions during ventilation caused fragmentation of the airflow in all patients. There was wide variation in the number and volume of the fragments between patients. The importance of quantification of airflow volumes and the effect fragmentation of the airflow on the efficacy of ventilation can be essential in improving cardiopulmonary resuscitation techniques and therefore needs further investigation.