Prognostic value of B-type natriuretic peptide (BNP) and its potential role in guiding fluid therapy in critically ill septic patients

Abstract

Background and objectivesThe prognostic role of B-type natriuretic peptide (BNP) in septic patients is controversial. The study aimed to investigate the prognostic value of BNP in critically ill septic patients. Furthermore, because BNP is primarily released from ventricles in response to myocardial stretch, the second aim of the study was to test whether the change in BNP was correlated to the amount of fluid balance.MethodsThis was a prospective observational study conducted in a tertiary 18-bed ICU. Patients fulfilled criteria of sepsis were enrolled. Exclusion criteria included renal dysfunction on ICU entry, age < 18 or >80 years old. BNP was measured on entry (BNP0) and day 3 (BNP1) and daily fluid balance over the three days were recorded. Diagnostic performances of BNP0 and ΔBNP (BNP1-BNP0) were analyzed. The correlation between fluid balance and ΔBNP were tested using Spearman’s correlation test.ResultsA total of 67 subjects were eligible for the study during study period. BNP0 was significantly higher in non-survivors than in survivors (738 vs 550 pg/ml, p < 0.01). The area under curves (AUCs) of BNP0 in predicting mortality, duration of mechanical ventilation (MV) > 7 d, length of stay in ICU (LOSICU) > 7 d and hospital (LOShospital) > 12 d were 0.71, 0.79, 0.66 and 0.71, respectively. The AUCs of ΔBNP in predicting duration of MV > 7 d, LOSICU > 7 d and LOShospital > 12 d were 0.80, 0.84 and 0.85, respectively. The amount of fluid balance was correlated to ΔBNP (Spearman’s rho = 0.63, p < 0.01), and the correlation remained statistically significant in multivariate model.ConclusionsBNP measured on ICU entry is associated with mortality, duration of MV, LOSICU and LOShospital. ΔBNP is able to predict the LOSICU and LOShospital with satisfactory sensitivity and specificity. ΔBNP is closely correlated to the amount of fluid balance during resuscitation period. However, this could only be considered as a hypothesis-generating pilot study due to its small sample size and the observational nature.

Early Management of Severe Sepsis

“…In this study, the 24-h fl uid balance was 37.5 mL/kg (about 2.5 L) in the survivors compared with 55.3 mL/kg (3.9 L) in those who died. Zhang and colleagues 47 demonstrated a strong correlation among the net fl uid balance, the increase in brain natriuretic peptide, and death in patients with sepsis. The most compelling data that fl uid loading in sepsis is harmful come from the Fluid Expansion as Supportive Therapy (FEAST) study performed in 3,141 sub-Saharan children with severe sepsis.…”

AME evidence series 001—The Society for Translational Medicine: clinical practice guidelines for diagnosis and early identification of sepsis in the hospital

“…False positive (e.g., patients testing positive for sepsis but actually not septic) will result in unnecessary resuscitation procedures, more antibiotic exposure, and higher cost. Extensive evidence shows that a persisting positive fluid balance is associated with adverse outcomes (51)(52)(53)(54)(55)(56). Therefore, inappropriate fluid management based on false positive results may create an unwarranted positive fluid balance with a corresponding higher mortality risk.…”

Fluid Therapy and Management

“…Yaşlılarda ANP artışı daha dramatiktir [11] . Natriüretik peptidler membrana bağlı proteoglikan ve glikoproteinlerin (özel-likle de sindekan-1 ve hyaluronik asit) çatlamasına ve endotelyal glikokaliksin bozulmasına yol açarlar [12,13] .…”