TRACHEAL GAS INSUFFLATION REDUCES REQUIREMENTS FOR MECHANICAL VENTILATION IN A RABBIT MODEL OF RESPIRATORY-DISTRESS SYNDROME

Tracheal gas insufflation is known to lower PaCO2 in larger animal mod els of respiratory distress syndrome, but its ability to reduce the ve ntilator pressures and tidal volume needed to achieve an acceptable Pa CO2 has not been examined in small animals using modes of ventilation employed in neonatal intensive care. In this study, the effect of insu fflating humidified gas into the lower trachea was examined in a salin e lung lavage model of respiratory distress syndrome in rabbits, while the peak airway pressure during conventional pressure-limited ventila tion was adjusted to keep the PaCO2 approximately constant. Tracheal g as insufflation significantly reduced the peak airway pressure require d and reduced the delivered tidal volume but did not affect the AaDO(2 ). The effects were more marked at a ventilator rate of 30 breaths per minute than at 60 bpm and more during continuous insufflation than wh en gas was insufflated only during expiration. These results suggest t hat tracheal gas insufflation may reduce the risk of ventilation-induc ed lung disease in the newborn.