Prognostic value of B-type natriuretic peptide in critically ill patients with new onset of fever: preliminary study

Introduction

The purpose of the study is the evaluation of B-type natriuretic peptide (BNP) as a predictor of septic complications and ICU mortality in patients with a new onset of fever during the first 3 days of hospitalization in the ICU.

Methods

Thirty-one ICU patients (21 males and 10 females) with new onset of fever and leukocytosis within the first 3 days of ICU admission were prospectively included in the study. Exclusion criteria were heart or renal failure, chronic obstructive pulmonary disease and head trauma. Serial plasma samples were taken on days 1, 2 and 4 after the onset of fever for BNP level measurement. BNP values were correlated with severity scores (Acute Physiology and Chronic Health Evaluation (APACHE II) and Sequential Organ Failure Assessment (SOFA)), the progression to septic shock and the final outcome.

Results

According to the clinical and laboratory findings within the first 3 days of hospitalization, the patients included in the study were divided into three groups: Group A = systemic inflammatory response syndrome (SIRS) (seven patients), Group B = sepsis (14 patients) and Group C = septic shock (10 patients). The BNP value on days 1 and 2 was significantly associated with the SOFA Max value (P < 0.001). The BNP value on day 4 was significantly associated with ICU mortality (P = 0.006). The optimal cutoff BNP value for differentiating between nonsurvivors and survivors was estimated to be 203.55 pg/ml (sensitivity = 100%, specificity = 61.1%). In Group B patients, BNP value on day 2 was significantly higher in patients who finally progressed to septic shock (P = 0.001). The optimal cutoff BNP value for identifying these patients was estimated to be 212.45 pg/ml (sensitivity = 85.7%, specificity = 64.3%).

Conclusions

In ICU patients with new onset of fever during the first 3 days of ICU hospitalization, the BNP value on day 4 seems to be a good predictor of ICU mortality. In patients with sepsis, a cut-off BNP value of 212.45 pg/ml on day 2 could be a predictor of progression to septic shock. Due to the small number of patients included in our study, further studies are needed to confirm these findings.