Repeated pulmonary function evaluation following bleomycin treatment.

A computerized, nonsurgical, pulmonary function measurement method was tested for sensitivity and utility in detecting the development of fibrosis. Bleomycin, a fibrogenic agent, was intratracheally instilled into male Fisher 344 rats. Respiratory function was monitored in restrained, awake animals before treatment and for the subsequent 4 wk. In the first week, among responders, a significant (p less than 0.05) drop in body weight, tidal volume, and compliance was accompanied by a significant increase in respiratory frequency. Minute volume increased in the second week. Although body weight, tidal volume, and compliance returned to baseline values in the following weeks, respiratory frequency and minute volume remained significantly elevated. With the methods used here, respiratory rate change was the parameter most sensitive to the effects of bleomycin in vivo.