The neonatal-pediatric specialist is unable to obtain a pulmonary capillary wedge pressure. Which of the following could be substituted for the wedge pressure?

• A. Pulmonary artery diastolic pressure
• B. Pulmonary artery systolic pressure
• C. Pulmonary vascular resistance
• D. Central venous pressure

Answer: (A)

Pulmonary capillary wedge pressure is used to estimate left atrial and left-sided filling pressures. If you can’t obtain the wedge, the best substitute is the pulmonary artery diastolic pressure because, in the absence of significant mitral valve disease or pulmonary vascular pathology, the diastolic pressure in the pulmonary artery tracks left atrial pressure more closely than the systolic pressure. The other options don’t reflect left-sided filling pressures: pulmonary artery systolic pressure reflects right ventricular ejection and overall pulmonary arterial pressure; central venous pressure reflects right atrial pressure; and pulmonary vascular resistance is a derived measure that requires a wedge value to compute.