[Surface-active properties of expirates in patients with acute pneumonia]

Surface activity of expirates, expired vapours was studied in 143 male patients, aged 18 to 20 years with acute pneumonia (AP). A colorimetric procedure based on estimation of the intensity of sudan solubilization by lipids contained in expirate condensates was used. The control group included 30 patients with acute bronchitis and 50 healthy persons of the same age and sex. The level of the expirate surface activity lowering depended on the volume of the lung tissue affection: in the patients with croupous and polysegmental focal pneumonia the changes were the most marked. In the patients with pneumococcal and staphylococcal AP the expirate surface activity (ESA) was significantly lower than in the patients with AP caused by streptococci and microbial associations. Analysis of relationships between the ESA and a complex of indices of external respiration revealed that in the majority of the cases the relationships were not linear except reverse correlation of the ESA to the expiration volumetric rate during the first second and the expiration maximum volumetric rate at the level of 50 per cent vital capacity of the lungs. In the patients with lingering AP the ESA at the disease peak was significantly lower than in the patients with the usual AP process. Complete normalization of the ESA was observed only in 24 per cent of the reconvalescents.