Positive end-expiratory pressure and renal function influence B-type natriuretic peptide in patients with severe sepsis and septic shock.

BACKGROUND Myocardial dysfunction is a complication associated with a poor prognosis in septic patients. A biomarker of cardiac function providing prognostic information is of paramount interest. OBJECTIVE We sought to determine the value of B-type natriuretic peptide in patients with severe sepsis/septic shock. METHODS We performed a prospective study in patients with severe sepsis/septic shock in a medical intensive care unit. B-type natriuretic peptide level was determined within 24 hours after the diagnosis of severe sepsis/septic shock. We also analyzed mortality, and presence of association between B-type natriuretic peptide and clinical, hemodynamic and respiratory variables. RESULTS 23 (9 women; 14 men) patients with ages ranging from 20-79 (mean 51.3+/-18.6) years old and APACHE score of 22.6+/-11.8 were included; 15 (65.2%) patients received pulmonary artery catheters, and 20 (87%) were mechanically ventilated. Multivariate analysis disclosed inverse association between B-type natriuretic peptide values with positive end-expiratory pressure values, and direct association with creatinine (beta 0.548 and 0.377, p 0.02 and 0.002, respectively), but not with mortality, clinical and hemodynamic parameters. CONCLUSION This is the first report on an inverse association between positive end-expiratory pressure and BNP levels in patients with severe sepsis and septic shock. BNP and creatinine levels should be taken into consideration when analyzing B-type natriuretic peptide levels in this setting.