Quality of Ventilations Performed During Out-of-Hospital Cardiac Arrest

Ian R Drennan, Brian Grunau, JP Heroux, Ian Hutt, Ben Johnson, Andrew Lee, Jonathan Peppler, Annabel Poitras, Richard Verbeek, Sheldon Cheskes

Introduction: Ventilations are an important, yet understudied component of cardiopulmonary resuscitation (CPR). The American Heart Association (AHA) recommends that ventilations are delivered with a tidal volume of 500-600ml and a rate of 10 to 12 per minute with an advanced airway (30:2 without). However, adherence to these recommendations during cardiac resuscitation is not known. 

Objective: To determine the quality of ventilations performed by prehospital providers during cardiac arrest management.

Methods: We included adult (>18 years) out-of-hospital cardiac arrest (OHCA) patients from four paramedic services in southern Ontario. Local OHCA protocols were in accordance with AHA guidelines. Ventilation quality was recorded using the ZOLL Accuvent® monitor. Prehospital providers were blinded to use of the real-time monitoring, however, data was collected with respect to ventilation rate and volume during the resuscitation as well as patient demographics and CPR quality. We excluded cases with less than five minutes of ventilation data. Our primary outcome was the average volume per ventilation, and secondary outcomes were the average ventilation rate per minute, and the proportion of ventilations (volume and rate) meeting AHA guideline recommendations.

Results. Of 97 OHCA, 20 had <5 minutes of data and were excluded. The remaining 77 cases had a mean age of 64 years (+/- 19) with 48 (62%) male; 31 (40%) were witnessed arrests, 21 (27%) had bystander CPR, 11 (15%) had initial shockable rhythms, and 49 (64%) had an advanced airway (tracheal intubation or supraglottic) inserted. The median volume per ventilation administered was 402ml (IQR 291ml to 461ml) with an average 18% of ventilations meeting AHA recommendations for tidal volume. The median ventilation rate was 14/min (IQR 11/min to 19/min) with an average of 27% of ventilations meeting AHA recommendations for ventilation rate. Overall, only 4% of the time were ventilations performed according to AHA recommendations (rate and volume combined).

Conclusion. Despite the recognized importance of proper ventilations, prehospital providers often do not meet guideline recommendations during cardiac resuscitation. The use of real-time feedback may help to improve ventilation quality.