Acute lobar collapse in canine lungs.

A series of experiments was carried out on 28 dogs in which the following aspects were investigated: in 9 dogs, the special configuration of acute lobar atelectasis; in 10 dogs, the pressure-volume characteristics of collapsed and non-collapsed diaphragmatic lobes; in 12 dogs, the wet-weight/dry-weight ratios of atelectatic contralateral lobes; in 6 dogs, the amount of blood sequestered in atelectatic diaphragmatic lobes was estimated. The relationships of an atelectic lobe closely resemble those described in man. Loss of apposition between visceral and parietal pleural surfaces was never observed. The W/D weight ratio of the collapsed lobe invariably was higher than that of the non-collapsed contralateral lobe indicating a slight increase in the volume of fluid in the atelectatic lobe. No pressure-volume differences were found between atelectatic and non-collapsed lobes.