What does pulmonary capillary wedge pressure (PCWP) estimate, and why is it important?

What does pulmonary capillary wedge pressure (PCWP) estimate, and why is it important?

• A. It estimates right atrial pressure.
• B. It estimates systemic vascular resistance.
• C. It estimates left atrial pressure and LV preload.
• D. It estimates right ventricular end-diastolic pressure.

Answer: (C)

Pulmonary capillary wedge pressure measures left-sided filling pressures. The balloon-tipped catheter is threaded into a distal branch of the pulmonary artery and inflated to wedge there. The pressure that can be read beyond the balloon reflects the pressure in the pulmonary capillaries, which communicates with the left atrium, so the wedge pressure closely mirrors left atrial pressure and, under normal conditions, left ventricular end-diastolic pressure (LV preload). This makes it a key indicator of left-sided preload and volume status, helping to assess causes of dyspnea and to guide fluid management and treatment of heart failure. Right atrial pressure is assessed by central venous pressure, not wedge pressure. Systemic vascular resistance is calculated from mean arterial pressure, central venous pressure, and cardiac output. Right ventricular end-diastolic pressure is measured in the right ventricle, not via the wedge technique.

Pulmonary capillary wedge pressure measures left-sided filling pressures. The balloon-tipped catheter is threaded into a distal branch of the pulmonary artery and inflated to wedge there. The pressure that can be read beyond the balloon reflects the pressure in the pulmonary capillaries, which communicates with the left atrium, so the wedge pressure closely mirrors left atrial pressure and, under normal conditions, left ventricular end-diastolic pressure (LV preload). This makes it a key indicator of left-sided preload and volume status, helping to assess causes of dyspnea and to guide fluid management and treatment of heart failure.

Right atrial pressure is assessed by central venous pressure, not wedge pressure. Systemic vascular resistance is calculated from mean arterial pressure, central venous pressure, and cardiac output. Right ventricular end-diastolic pressure is measured in the right ventricle, not via the wedge technique.