Effect of nitrogen on carbon dioxide elimination during continuous flow apneic ventilation in dogs

Continuous endobronchial insufflation of air in paralyzed animals (continuous flow apneic ventilation - CFAV) has been shown to maintain adequate oxygenation and carbon dioxide removal. CFAV in patients using oxygen resulted in adequate oxygenation but a mean rise in PaCO2 of 0.6 mmHg/min (0.08 kPa/min). This experiment compared carbon dioxide removal in dogs with air and oxygen. Ten dogs were anesthetized and paralyzed, and CFAV was used for 1 h with either air or oxygen in a randomized fashion. Adequate oxygenation was obtained with air and oxygen. Normal PaCO2 levels were obtained with air; however, in the animals where oxygen was used, PaCO2 levels rose to a mean of 6.45 +/- s.e. mean 0.4 kPa (48.5 +/- s.e.mean 3.2 mmHg).