Chest compression synchronized ventilation during prolonged experimental cardiopulmonary resuscitation improves oxygenation but may cause pneumothoraces

Abstract

Chest compression synchronized ventilation (CCSV) has been proposed to provide superior ventilation and haemodynamics during cardiac arrest (CA) compared to conventional asynchronous ventilation and compressions. We compared arterial gas exchange, pH, lactate levels and haemodynamics between CCSV and manual asynchronous ventilation during prolonged experimental CA. We randomized 30 pigs (weight ca. 55 kg) to receive CCSV with a MEDUMAT Standard 2 ventilator or a manual bag valve targeting 10–12 ventilations per minute. Chest compressions were provided with a Lucas® 2 device. Arterial samples were drawn every 5 min and monitoring was recorded continuously. The animals underwent chest CT scans after death. The median intra-arrest arterial blood gas results for CCSV were PaO 2 = 490 (86–570) mmHg, PaCO 2 = 20 (10–35) mmHg and pH = 7.39 (7.19–7.53). In the manual ventilation group, the results were PaO 2 = 304 (109–379), PaCO 2 = 36 (28–47) and pH = 7.24 (7.12–7.34). The oxygen levels were significantly higher in the CCSV group compared to a linear mixed model ( p = 0.046). The differences in CO 2 and pH levels were not statistically significant. The minute volumes and positive end-expiratory pressures were higher in the CCSV (18.0 [15.3–19.8] l/min; 32.6 [29.2–35.6] cmH 2 O) group compared to the control group (5.7 [4.9–7.0] l/min; 2.8 [1.8–4.1] cmH 2 O). The CCSV group had 12 pneumothoraces compared to 3 in the control group ( p = 0.008). The CCSV protocol resulted in higher arterial oxygenation but more pneumothoraces. The study was approved by the Finnish National Animal Experiment Board (ESAVI-26974-2023).