Tracheal gas insufflation is known to lower PaCO2 in larger animal models of respiratory distress syndrome, but its ability to reduce the ventilator pressures and tidal volume needed to achieve an acceptable PaCO2 has not been examined in small animals using modes of ventilation employed in neonatal intensive care. In this study, the effect of insufflating humidified gas into the lower trachea was examined in a saline lung lavage model of respiratory distress syndrome in rabbits, while the peak airway pressure during conventional pressure-limited ventilation was adjusted to keep the PaCO2 approximately constant. Tracheal gas insufflation significantly reduced the peak airway pressure required and reduced the delivered tidal volume but did not affect the AaDO2. The effects were more marked at a ventilator rate of 30 breaths per minute than at 60 bpm and more during continuous insufflation than when gas was insufflated only during expiration. These results suggest that tracheal gas insufflation may reduce the risk of ventilation-induced lung disease in the newborn.