The effect of different ventilation modes on the ventilation rate and prognosis in patients with cardiac arrest after advanced airway placement

Objective To investigate the effect of different ventilation modes on the ventilation rate and prognosis in patients with cardiac arrest after advanced airway placement. Methods Based on the national database of emergency cardiac arrest treatment, patients treated with advanced airway placement during cardiopulmonary resuscitation (CPR) were enrolled in PUMCH Emergency Department from December 2013 to June 2018. The physiological parameters, such as electrocardiograph waveform, pulse oximetry plethysmographic waveform and capnography, were recorded at least 18 minutes. The demographic data and resuscitation parameters were collected. Waveform capnography was used for calculating ventilation rate (VR) and the VR between 8 to 12 breaths/min was defined as the qualified ventilation rate (QVR). According to the ventilation modes, patients were divided into the bag-mask group (BMG) and mechanical ventilation group (MVG). According to the VR, patients in the mechanical ventilation group were divided into two subgroups, the high-frequency ventilation subgroup (HFV subgroup) with the VR more than 20 breaths/min and the low-frequency VR subgroup (LFV subgroup) with the VR less than 20 breaths/min. VR, the qualified ventilation rate ratio (QVRR), the return of spontaneous circulation (ROSC), and 24-h and 7-day survival were compared between the two groups and subgroups. Result A total of 90 patients were enrolled in the analysis with 22 patients in the bag-mask group and 68 patients in the mechanical ventilation group. The total rate of ROSC was 35.6%, 24-h survival was 1.1% and 7-day survival was 0. The first 18 minutes ventilation data were collected and added up to 1 620 min. The median VR was 16.5 (12.0, 26.0) breaths/min and the QVRR was 30%. Compared with the mechanical ventilation group, the VR in the bag-mask group were lower (10 breaths/min vs 21 breaths/min) and the QVRR was higher (88.9% vs 11.5%). The ROSC, 24-h survival and 7-day survival had no statistical differences between the two groups. In the mechanical ventilation group, the ratio of VR more than 20 breaths/min was 52.6%. Between the two subgroups, there was no statistical difference in ROSC, 24-h survival and 7-day survival. Conclusions Compared with the mechanical ventilation during CPR, the VR is lower with bag-mask ventilation, and the QVRR is higher. But there was no statistical difference on the outcomes. There was no difference on the outcomes between the two mechanical ventilation subgroups. Key words: Cardiac arrest; Cardiopulmonary resuscitation; Mechanical ventilation; Ventilation rate; Bag-mask ventilation