Does B-type natriuretic peptide measurement correlate with hemodynamics and predict mortality in critically ill intensive care unit patients with shock?
In ICU patients with shock, BNP levels do not correlate with pulmonary artery catheter hemodynamics but serve as a strong independent predictor of mortality.
OBJECTIVES: Among patients with congestive heart failure, B-type natriuretic peptide measurement is useful to estimate filling pressures and to prognosticate adverse outcome. However, among critically ill intensive care unit patients with shock, the utility of B-type natriuretic peptide to assess cardiac hemodynamics or prognosis has not been explored. DESIGN: Clinical investigation. SETTING: Hospital. PATIENTS: Forty-nine patients with shock and indication for pulmonary artery catheterization. INTERVENTIONS: Analysis for B-type natriuretic peptide was performed on blood obtained at the time of catheter placement. MEASUREMENTS AND MAIN RESULTS: Correlations between B-type natriuretic peptide and pulmonary artery occlusion pressure as well as cardiac index were calculated using Spearman analysis. Mortality at the time of study completion was correlated with B-type natriuretic peptide values and Acute Physiology and Chronic Health Evaluation II scores, and logistic regression identified independent predictors of mortality. A wide range of B-type natriuretic peptide concentrations was seen in intensive care unit patients (5000 pg/mL); only eight patients (16%) had normal B-type natriuretic peptide concentrations. Log-transformed B-type natriuretic peptide concentrations did not correlate with interpatient cardiac index or pulmonary artery occlusion pressure (all p = not significant); however, a B-type natriuretic peptide <350 pg/mL had a negative predictive value of 95% for the diagnosis of cardiogenic shock. Median B-type natriuretic peptide concentrations were higher in those who died than those who survived (943 pg/mL vs. 378 pg/mL, p <.001). In multivariable analysis, a B-type natriuretic peptide concentration in the highest log-quartile was the strongest predictor of mortality (odds ratio = 4.50, 95% confidence interval = 1.87-99.0, p <.001). CONCLUSION: B-type natriuretic peptide concentrations are frequently elevated among critically ill patients in the intensive care unit and cannot be used as a surrogate for pulmonary artery catheterization. B-type natriuretic peptide concentrations in intensive care unit shock may provide powerful information for use in mortality prediction.
Tung et al. (Sun,) studied this question.