Effects of tracheal insufflation of oxygen (TRIO) on blood gases during external cardiac compressions in dogs under ventricular fibrillation.

Tracheal insufflation of oxygen (TRIO) is a form of constant-flow ventilation. We studied the effect of TRIO at a flow rate of 2 L/kg/min on arterial blood gases during external cardiac compressions in dogs with ventricular fibrillation. During the combined application of TRIO and external cardiac compressions, all animals were adequately oxygenated and hyperventilated except in cases where lung edema developed in the course of cardiopulmonary resuscitation (CPR). No pulmonary barotrauma was observed. The findings suggest that TRIO might be used as a temporary measure for emergency ventilation when CPR is performed in certain situations such as upper airway abnormalities or cardiac arrest outside the hospital setting, where intermittent positive pressure ventilation is not feasible.