Atrial natriuretic peptide improves pulmonary gas exchange by reducing extravascular lung water in canine model with oleic acid-induced pulmonary edema

Objective: The purpose of this study was to examine and compare the effects of atrial natriuretic peptide and furosemide on pulmonary gas exchange, hemodynamics, extravascular lung water, and renal function in a dog model of oleic acid-induced pulmonary edema. Design: Prospective, comparable, experimental study. Setting. Laboratory at a university hospital. Subjects. Eighteen male beagle dogs were studied under mechanical ventilation with pentobarbital anesthesia. Interventions. Oleic acid (0.08 mL/kg) was injected and allowed for I hr to achieve pulmonary edema with hypoxemia at Fio(2) of 0.3. After lung injury, dogs were divided into three groups; control group (n = 6) receiving saline (2.5 mL/hr for 5 hrs), atrial natriuretic peptide group (n = 6) receiving atrial natriuretic peptide (1 mug.kg(-1).min(-1) for 5 hrs), and furosemide group (n = 6) receiving furosemide (I mg.kg(-1).hr(-1) for 5 hrs). Measurements and Main Results. Hemodynamics, arterial blood gases, extravascular lung water, and renal function were measured hourly for 7 hrs after injury. Oleic acid increased extravascular lung water and induced hypoxemia. In the atrial natriuretic peptide group, extravascular lung water was significantly (p < .05) lower and Pao(2) was significantly (p < .05) higher than in the control and furosemide groups, respectively. Pulmonary hypertension induced by oleic acid was attenuated by atrial natriuretic peptide infusion but not by saline or furosemide. Increased natriuresis/diuresis did not significantly differ between the atrial natriuretic peptide and the furosemide group, whereas creatinine clearance in the atrial natriuretic peptide group was significantly higher than that in the furosemide group. Conclusions. These findings suggest that atrial natriuretic peptide improves pulmonary gas exchange by reducing extravascular lung water and pulmonary arterial pressure, possibly independently from natriuresis/diuresis in oleic acid-induced pulmonary edema.