PROGNOSTIC VALUE OF PULMONARY FUNCTION TESTS IN EMPHYSEMA - WITH SPECIAL REFERENCE TO ARTERIAL BLOOD STUDIES

Abstract

Prognostic criteria were studied in 83 patients with diffuse obstructive emphysema, with particular reference to certain clinical features and to spirographic and arterial blood gas studies during a follow-up period of 2 to 6 years. Forty-eight patients died during this period, 33 are still living, and 2 were lost to follow-up. Cumulative death rates per patient years were calculated by a modified life-table method, and the significance of differences between the observed and expected number of deaths was determined by the chi-square test. Emphysema patients were Classified into 3 clinical types: "primary" emphysema (dyspnea was the first symptom), "bronchitis" emphysema (bronchitis preceded dyspnea), and "cachectic" emphysema (simultaneous onset of dyspnea and weight loss). Death rates calculated from the onset of dyspnea were highest in the "cachectic" group and lowest in the "primary" group. No significant difference was found between the death rates per dyspnea-years for males vs. females in the series. The onset of cardiac failure and/or weight loss was associated with poor prognosis. Cardiac failure was the chief cause of death among the 48 who died during the follow-up period. The severity of dyspnea per se was not a useful means of predicting those who would die during the period of follow-up. Four parameters of pulmonary function, MW [maximum voluntary ventilation] FVC [forced vital capacity] SaO2 [arterial O2 saturation] and PaCO2 [arterial CO2 tension] were found to be significantly related to prognosis, whereas the ratio FEV3.0 q/FVC and hematocrit values were not. Since severe impairment in one measurement of pulmonary function is not necessarily associated with comparable impairment in others, multiple tests are necessary for an adequate estimate of prognosis in obstructive emphysema.