The study of pro-B-type natriuretic peptide in the evaluation of the cardiac function in patients with severe sepsis

Abstract

To evaluate plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels as a marker of cardiac function during severe sepsis and septic shock. A prospective study was conducted, and 44 patients without history of heart diseases but suffering from severe sepsis and septic shock underwent the transesophageal echocardiography (TEE) to obtain data about left and right ventricular function on 1, 3, 7 days in intensive care unit (ICU). At the same time, blood samples were collected to measure the levels of plasma NT-proBNP, quality of creatine kinase isoenzyme (CK-MBmass), troponin T (cTnT) and lactate. The factors affecting plasma NT-proBNP levels in patients with severe sepsis and septic shock were analyzed, and correlation between NT-proBNP and cardiac function indexes were evaluated. Of 44 patient with severe sepsis and septic shock, 21 cases died in 28 days, with the mortality rate of 47.73%. The plasma NT-proBNP values on 1, 3, 7 days in ICU of 21 non-survivors were obviously higher than those of 23 survivors [10 112 (855-35 000) ng/L vs. 4 116 (185-28 437)ng/L, Z=-2.622, P=0.009; 13 811 (1 127-35 000) ng/L vs. 899 (116-35 000)ng/L, Z=-3.459, P=0.000; 6 786 (398-35 000) ng/L vs. 623 (98-4 118)ng/L, Z=-3.001, P=0.003]. Non-conditional logistic regression analysis and linear regression analysis, plasma lactate (t=2.420, P=0.020) and acute physiology and chronic health evaluation system II (APACHEII) score (t=3.482, P=0.001) on day 1, and left ventricular ejection fraction (LVEF, t=-2.326, P=0.029) on day 7 showed that they were independent affecting factors for plasma NT-proBNP levels. Patients were subdivided into two groups based on LVEF. It was found that the plasma NT-proBNP values in abnormal group (LVEF<0.50, n=8) were significantly higher than those in normal group (LVEF≥0.50, n=17) on day 7 [1 231 (398-5 000) ng/L vs. 513 (98-10 047) ng/L, Z=-1.831, P=0.047]. Plasma NT-proBNP levels on day 7 in ICU could reflect the left ventricular systolic dysfunction in patients with severe sepsis and septic shock.