Natriuretic peptide type B in burn intensive care

Abstract

BACKGROUND: The plasma concentration of natriuretic peptide type B (BNP) or NT-proBNP (P-BNP or P-NT-proBNP) reflects cardiac load. In intensive care unit settings and in chronic inflammation, it is also affected by non-heart-related mechanisms. It has been suggested to be a marker of hydration after severe burns and to predict outcome in critically ill patients, but results are contradictory. We therefore measured P-NT-proBNP after severe burns and related it to injury related variables and to organ dysfunction. METHODS: Fifty consecutive patients with a burn size greater than 10% were studied for the first 2 weeks. P-NT-proBNP changes were analyzed in relation to burn size, age, changes in body weight, C-reactive protein in plasma, and organ function assessed as Sequential Organ Failure Assessment (SOFA) scores RESULTS: P-NT-proBNP showed large day-to-day and between patient variations. Daily change in body weight correlated with P-NT-proBNP only on Day 2, when maximum mobilization of edema occurred. Thereafter, P-NT-proBNP correlated with C-reactive protein in plasma as well as with SOFA scores. Burn size correlated with maximal weight change, which in turn correlated with both time for and value of maximum P-NT-proBNP. Maximal P-NT-proBNP was related to mortality and correlated better with SOFA score on Day 14 compared with age and burn size. In linear regressions, together with age at injury and total body surface area, P-NT-proBNP assessed on Days 3 to 8 was an independent predictor for every subsequent SOFA score measured one or more days later up to Day 14. CONCLUSION: P-NT-proBNP exhibited considerable interindividual and day-to-day variations. Values were related to mortality, burn size, water accumulation, posttraumatic response, and organ function. Maximum P-NT-proBNP correlated stronger with length of stay and with organ function on Day 14, compared with age and burn size. High values in Days 3 through 8 were also independent predictors of subsequent organ function up to 2 weeks after injury. LEVEL OF EVIDENCE: Epidemiologic/prognostic study, level III.