Ultrastructure of the lung after ventilation.

We looked at the ultrastructure of the lung of rabbits ventilated with air moistened with nebulized water ("nebulized group"), and humidified air ("humidified group") compared to a group of controls. Both groups of ventilated rabbits had plasmalemmal vesicles that were larger than in controls. They were fewer in number (P less than 0.001) and less well defined. Early degenerative changes were noted in 6 of 9 rabbits in the nebulized group and 6 of 9 rabbits in the humidified group, while none of the rabbits in the control group were similarly affected. Interstitial oedema of varying severity was seen in 6/9 rabbits from each of the ventilated groups.