Prognostic Value Of N-terminal Pro-B-type Natriuretic Peptide In Critically Ill Patients

Objective:To investigate whether plasma N-terminal pro brain natriuretic peptide (NT-pro-BNP) measured at admission to intensive care unit(ICU) is an independent predictor of mortality in critically ill patients.Methods : A prospective observational study of ICU patients in ICU was conducted.One hundred and twenty Patients aged>18 years were included during a 6-month period. Among them 88 patients were enrolled for study. Plasma NT-pro-BNP samples were obtained at admission to ICU. The acute physiology and chronic health evaluation II (APACHE II) score was calculated within 24 hours after admission based on the worst values up to that point. The final evaluation was 28-day mortality.Results :Thirty-five patients died within 28 days of ICU admission, the mortality was 39.8%. In 88 patients, the mean plasma NT-pro-BNP levels(ng/l)were 1221.7(78.7-5500).and that in survivor group had significantly lower than non-survivors group (781.8[ 78.7-5066.6] vs.2774.5 [166.8-5500], survivors vs. nonsurvivors, respectively, P<0.01). The mean NT-pro-BNP levels (ng/l)in male patients was higher than that in females[1585.5(103.7-5100)vs.794.5 (78.7-5500), P<0.05]. There was correlation between gender and NT-pro-BNP levels (r=-0.224,p<0.05). Patients admitted to the ICU because of a severe infection had higher levels of NT-pro-BNP (ng/l) compared with the rest of the cohort (3416.1[103.7-5100ng/l] vs. 883.4[78. 7-5500], P<0.01). There was correlation between severe infection at admission to ICU and NT-pro-BNP levels(r=0.285,P<0.01) . Areas under the receiver operating characteristic curves (ROC curves) of NT-pro-BNP and APACHEII Score were respectively 0.734[95% confidence interval (95%CI) 0.628-0.84] and 0.747 ( 95%CI 0.637-0.858 ) ,respectively.Logistic regression analysis show that the NT-pro-BNP level more than the threshold of 1418 ng/l and the APACHE II score were independently associated with 28-day mortality [odds ratio(OR)5.235,95%CI 1.819-15.071] vs. OR1.105,95%CI 1.819-15.071], With 1415ng/l Of NT-pro-BNP as the cutoff value ,survival rate was significantly lower in the patients with higher NT-pro-BNP level as compared with those with lower values at admission (X2=16.9,P<0.01).Conclusion :The ICU admission NT-pro-BNP level higher than 1418ng/l and APACHE II score at admission are independent markers of early mortality. NT-pro-BNP might serve as a potent early diagnostic and distinguishable marker in critically ill patients.