Elastic recoil pressure arising from surface tension in hamster lungs treated with intratracheal bleomycin

Lung elastic recoil pressure arising from surface tension (Ps) was evaluated in normal and bleomycin-treated lungs. Twenty two male golden hamsters were separated into a control group (group A, n = 10) and a bleomycin group (group B, n = 12). Group B was given a single intratracheal instillation of bleomycin and group A was given normal saline as a control. Thirty days after instillation, three cycles of static air -and saline-filled pressure-volume curves (P-V curve) were measured. Ps was graphically derived from air- and saline-filled P-V curves. The Ps of groups A and B were compared at the same lung volumes. Mean body weight and nose-to-tail length of the two groups did not differ significantly. Total lung capacity, defined as lung air volume at a transpulmonary pressure of 25 cmH2O, was significantly smaller in group B (mean +/- S.E. was 4.08 +/- 0.20 ml) than in group A (mean +/- S.E. was 5.23 +/- 0.12 ml) (p less than 0.01). The Ps of group B was significantly larger than that of group A at all lung volumes studied (p less than 0.01-0.05). These results indicate that the lung elastic recoil pressure component due to the surface tension was increased by intratracheal instillation of bleomycin in hamsters.