Effect of acute lung injury and coexisting disorders on plasma concentrations of atrial natriuretic peptide

Abstract

Objective: To clarify how plasma atrial natriuretic peptide concentrations vary with the severity of acute lung injury. The influence of coexisting diseases which trigger acute lung injury was also examined. Design: Prospective study. Setting: Intensive care unit of a university hospital. Patients: Fifty patients who had standard risk factors for acute lung injury including sepsis syndrome, major surgery, prolonged hypotension, aspiration of gastric contents, and burns. Twenty-five of these patients had acute lung injury (group 3) caused by these disorders; the remaining 25 patients had risk factors only (group 2). Ten age-matched normal volunteers were selected as controls (group 1). Intervention: None. Measurements and Main Results: Plasma atrial natriuretic peptide concentration was measured in these patients and compared with the severity of acute lung injury. In group 3, a significant increase in the mean plasma atrial natriuretic peptide concentration was observed (188 ± 78 pg/mL,p< .01) compared with group 2 (54 ± 28 pg/mL) and the age-matched control group (30 ± 8 pg/mL). This increase was related to the onset of acute lung injury and returned to control concentrations after recovery. Plasma atrial natriuretic peptide concentrations in group 3 correlated highly with a lung injury score representing the severity of acute lung injury (r2 = .45,p< .01), but did not correlate with other cardiopulmonary variables. Conclusion: The results suggest that severity of lung injury, but not other predisposing disorders, may be the key factor leading to the increase in plasma atrial natriuretic peptide concentrations observed in these patients. (Crit Care Med 1994; 22:1762–1768)