Cardiopulmonary resuscitation without intermittent positive pressure ventilation

The purpose of this study was to examine whether tracheal insufflation of oxygen (TRIO) could be used as a substitute for intermittent positive pressure ventilation (IPPV) during cardiopulmonary resuscitation (CPR) in dogs with orotracheal intubation. Twenty-seven anesthetized, paralyzed and intubated dogs were used. The tip of the insufflation catheter was placed 1 cm distal to the top of the endotracheal tube. The effects of TRIO at a flow rate of 10 l/min with or without a continuous positive airway pressure (CPAP) of 5 cmH2O during external cardiac compressions were compared with those managed under the standard CPR. During CPR, TRIO without CPAP maintained adequate gas exchange. Peak airway pressures in the TRIO groups were significantly lower than that in the standard CPR group. No significant differences were observed in arterial, pulmonary artery and diastolic right atrial pressures during CPR among the three groups. However, the coronary perfusion pressures in the TRIO group with CPAP always tended to be low during CPR. The present study suggests that TRIO without CPAP should be a promising substitute for IPPV during CPR when IPPV is not feasible.