Forced oscillatory resistance and compliance parameters following pneumonectomy in beagle dogs.

Forced oscillatory resistance (RFO) and compliance (CFO) were measured in 3 groups of adult beagle dogs. Group I (n = 12) had undergone a left pneumonectomy at 6-10 weeks of age; group II (n = 11) underwent a similar procedure at 1 year of age; and group III (n = 8) served as unoperated controls. The mean value of RFO for group II was significantly higher than corresponding values for groups I and III. Similarly, the mean value of CFO was significantly lower for group II. Mean values for RFO and CFO between groups I and III were not statistically different. When RFO and CFO were normalized by functional residual capacity, mean values for all three groups were similar. However, when RFO and CFO were normalized by body weight, mean values for groups I and II were significantly different from those of group III. These findings cannot be explained directly by postoperative hyperinflation of the remaining lung. They suggest that there is an adaptive change in the mechanical characteristics of the remaining lung following pneumonectomy and that the degree of adaptation varies with the age of the animal undergoing resection.