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

Continuous endobronchial insumation 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 Pacos 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).