Effect of continuous oxygen insufflation on induced-gastric air volume during cardiopulmonary resuscitation in a cadaveric model

BackgroundThe main objective of this study was to compare the volume of gas insufflated in the stomach with continuous external chest compressions plus continuous oxygen insufflation (C-CPR) versus standard-CPR (S-CPR) which alternates external chest compressions and synchronized positive insufflations through a bag-valve-mask with a 30/2 ratio. The secondary objective was to compare upper airway pressures (intratracheal and intramask) generated during continuous oxygen insufflation.Material and methodsOpen, prospective, randomized, cross over, comparative, non-inferiority study. CPR was performed for six minutes periods, on seven fresh human corpses, with C-CPR or S-CPR in a random order. Before each CPR period, the stomach was completely emptied through the gastrostomy tube, and then 200 mL of air was injected in the stomach to be sure it was not collapsed. The gastric volume was measured at the end of each intervention. Intratracheal and intramask pressures were recorded continuously during C-CPR. Results were provided as mean ± standard deviation. Statistical analyses were done with a paired student t test.ResultsInduced-gastric inflation was lower with C-CPR (221 ± 130 mL) than with S-CPR (5401 ± 2208 mL, p = 0.001). Throughout C-CPR, no difference was found between the intratracheal and intramask pressures (4.4 ± 1.2; 4.0 ± 0.8 cmH2O, respectively, p = 0.45).ConclusionThis human cadaver study demonstrates that continuous oxygen insufflation induced less gastric inflation than intermittent insufflation during CPR.