What is wedge pressure?

Choice A rationale A measurement that reflects the pressure in the superior vena cava is the central venous pressure (CVP). CVP is a direct measurement of the pressure in the vena cava, which reflects the pressure in the right atrium, not the left ventricular end-diastolic pressure. Choice B rationale A measurement that reflects the pressure in the right atrium is the central venous pressure (CVP), also known as right atrial pressure. This pressure primarily indicates the right-sided cardiac function and the patient's fluid status, not the left ventricular function. Choice C rationale The wedge pressure is a measurement that reflects the pressure on the left side of the heart. The pressures in the atria, both right and left, are not directly measured by wedge pressure; instead, it is an indirect reflection of the left ventricular end-diastolic pressure (LVEDP), which is an indicator of left ventricular function. Choice D rationale Wedge pressure, specifically the pulmonary artery wedge pressure (PAWP), is measured by inflating a balloon on the tip of a pulmonary artery catheter, which allows it to "wedge" into a small pulmonary artery. This temporarily obstructs blood flow from the right side and provides a pressure reading that approximates the left atrial pressure, which in turn, reflects the left ventricular end-diastolic pressure (LVEDP), or preload.