BNP is correlated with which measurement because it is released in response to increased intravascular volume?

B-type natriuretic peptide (BNP) is a hormone released by the ventricles of the heart in response to increased stretch due to elevated intravascular volume, which commonly occurs in states such as heart failure. The measurement that closely correlates with BNP levels is pulmonary artery occlusion pressure (PAOP), also known as wedge pressure.

PAOP reflects the left atrial pressure and thus gives an indication of the filling pressures and volume status of the left side of the heart. When intravascular volume increases, it leads to increased pressure in the heart chambers, particularly the left atrium, resulting in the release of BNP as a compensatory mechanism. Therefore, measuring BNP can help estimate changes in PAOP, which in turn assists in the assessment of heart failure severity and fluid overload states. This correlation is particularly valuable in the critical care setting, where understanding volume status is essential for patient management. The other options do not directly measure intravascular volume changes in the same way.