Pitfalls in Pulmonary Artery Catheter Data Interpretation

Abstract

Estimation of left-sided vascular pressures via catheterization of the right heart requires a static uninterrupted column of blood to be present from the tip of the PA catheter (PAC) to the aortic valve. At the end of diastole, there is no net flow in this common chamber, and if the pulmonary vascular bed distal to the PAC tip is patent, no pressure gradients should exist and the pulmonary wedge pressure (WP) should approximate the mean pulmonary venous (PVP), left atrial (LAP) and left ventricular end diastolic pressures (LVEDP) (Figure 1). Alterations in intrathoracic pressure may markedly affect measurement of the pulmonary wedge pressure.