Purpose of the study 
The purpose of our study is to investigate whether endotracheal intubation is associated with increased chest compression fraction during out of hospital cardiac arrest management. 
Material and methods
The study was conducted by the prehospital medical team from CHU Saint Pierre in Brussels while participating to the CAAM study, a randomized controlled trial randomizing patients to endotracheal tube (ET) versus bag valve mask (BVM) ventilation during arrest. We conducted a post-hoc analysis of high resolution data collected during the first 40 minutes of OHCA through Corpulse. ECG recordings, audio recordings and when available, accelerometer recordings were analyzed to determine CPR quality. 
Results
We observed no difference in terms of chest compression fraction when comparing ET CCF to BVM CCF during the whole duration of the arrest (0.9 vs 0.886; p=0.19). When analyzing the intervention by 10 minutes intervals we observed that CCF was significantly higher in the ET group from the 11th minute until the 20th minute (0.903 vs 0.821; p<0.001). When analyzing the intervention cycle by cycle we observed a significant lower CCF in patients randomized to ET versus patients randomized to (BVM) during the first cycle (0.743 vs 0.810 p=0.02). Finally we observed that patients randomized to ET had significant higher durations of chest compressions pauses associated to LUCAS placement (23.6 vs 33.7 p=0.02) and rhythm analysis (81.1 vs 67.7; p=0.02). 
Conclusions
Our study does not support the hypothesis of higher rates of CCF associated with ET placement during OHCA. Our study shows significant increases in pauses associated with LUCAS placement and rhythm analysis in patients randomized to ET.

7 - Endotracheal intubation is not associated with increased chest compression fraction during out of hospital cardiac arrest. A Post-hoc analysis of a single center high resolution arrest management data from the CAAM study.