Alveolar surface area-to-lung volume ratio in oleic acid-induced pulmonary edema.
It is unknown how the in vivo alveolar surface area-to-volume ratio (S/V) changes in low-pressure pulmonary edema. Here, the S/V is the area of the air-tissue interface per unit total volume (air plus tissue). We hypothesized that in oleic acid (OA)-induced edema inactivation of the pulmonary surfactant may increase surface tension and decrease the S/V at any given lung volume. OA (0.04 mg/kg) was intravenously injected into dogs. We measured the in vivo S/V (equivalent to the inverse of optical mean free path by light-scattering stereology and the pressure-volume (PV) curve 60-90 min after OA administration. OA administration decreased the lung volume at each transpulmonary pressure and increased the wet-to-dry weight ratio. The S/V decreased after OA administration (optical mean free path increased). The air-filled PV curves shifted downward after OA, but the saline-filled PV curves after OA administration did not differ significantly from control saline-filled curves. The difference in transpulmonary pressure between air- and saline-filled PV curves (an index of the magnitude of surface tension) was increased in OA-induced pulmonary edema. This study suggests that in OA-induced pulmonary edema the alveolar surface tension increases and the S/V decreases, presumably due to inactivation of surfactant by serum leakage to alveoli.
Suzuki
S
S
First Department of Internal Medicine, Yokohama City University School of Medicine, Japan.
Akahori
T
T
Miyazawa
N
N
Numata
M
M
Okubo
T
T
Butler
J P
JP
D000818:Animals; D004285:Dogs; D007700:Kinetics; D008168:Lung / Q000503:physiopathology*; D009829:Oleic Acids / Q000494:pharmacology*; D011654:Pulmonary Edema / Q000139:chemically induced*; D013500:Surface Tension
D009829:Oleic Acids