Meniscus formation in airways of excised rat lungs.
Frazer-DG; Stengel-PW; Weber-KC
Respir Physiol 1979 Feb; 36(2):121-129
The conditions required for menisci formation in the airways of excised lungs were investigated. Lungs were excised from Long-Evans- Hooded-rats and ventilated in a plethysmograph for two sequences of six cycles each. The cycles consisted of inflating and deflating the lung between various combinations of a minimum pressure of negative 6 centimeters (cm) of water and a maximum pressure of positive 30cm. The second sequence was in reverse order of the first. Transpulmonary pressure and lung volume were determined. In sequence 1, the volume of trapped gas in the lung increased as the minimum pressure decreased. In sequence 2, air was trapped at higher pressures. The amount of air trapped in the lungs was assumed to be directly proportional to the number of airways in which menisci had formed during deflation. In both sequences, about 68 percent of the airways had at least one meniscus formed between 1.4 and 3.0cm of water during deflation. The authors conclude that the minimum pressure affects the amount of air trapped in the lung, which in turn is indicative of the amount of menisci in the airways.
NIOSH-Author; Laboratory-animals; Pulmonary-system; Pulmonary-function; Respiratory-gas-transport; Respiratory-gas-analysis; Respiratory-gases; Physiology;
Author Keywords: Airway closure; Excised rat lungs; Foam formation in lungs; Lung pressure volume curves
Appalachian Laboratory for Occupational Safety and Health, National Institute for Occupational Safety and Health, Center for Disease Control, U.S. Public Health Service, Morgantown, WV 26506, U.S.A.