The applications of B-type natriuretic peptide measurement in the intensive care unit

Plasma B-type natriuretic peptide levels are used to screen for cardiac dysfunction in the emergency department and outpatient population. However, in the critically ill patient elevated plasma B-type natriuretic peptide levels do not necessarily reflect just ventricular dysfunction, as there are important confounding factors to consider. This review summarizes the recent advances in the application of B-type natriuretic peptide measurement in the intensive care unit.

B-Type natriuretic peptide levels are very useful in identifying cardiac dysfunction but not the specific pathology, whether it is right or left ventricular failure, diastolic or systolic dysfunction. Elevated serum B-type natriuretic peptide levels also occur in severe sepsis or septic shock. It also predicts cardiac dysfunction in sepsis. The lack of correlation of B-type natriuretic peptide concentrations with filling pressures in the intensive care unit precludes its use for monitoring cardiac therapy. Some studies involving patients with sepsis or septic shock demonstrate a positive correlation with mortality, while others failed to establish such a relation. The prognostic value of B-type natriuretic peptide in predicting mortality and morbidity remains controversial, partly due to different study designs.

B-Type natriuretic peptide is potentially a very useful diagnostic tool in the intensive care unit. To date there have been few studies and the results are often contradictory, mainly due to the special setting of the intensive care unit, which is constantly exposed to hemodynamically unstable patients, different case mixes as well as vigorous treatments. All of these are potential confounders to B-type natriuretic peptide levels and make interpretations of B-type natriuretic peptide difficult. We need more research on these confounding factors to accentuate the positive value of B-type natriuretic peptide in the intensive care unit.