Saturday May 05, 2007
Revisiting Pulmonary Artery Diastolic-Pulmonary Wedge Pressure Gradient

Floatation of pulmonary artery catheter (PAC) in ICUs is towards downward trend. Lets revisit one important but forgotten value obtained via PAC.

PADP - PAOP
(Pulmonary Artery Diastolic-Pulmonary Wedge Pressure) Gradient.

Most of the literature in regards to this value is 15-30 years old but proven to be very easy to calculate but very vital to follow 1, 3. Once this gradient starts to exceeds by 6 mm Hg or more, the patient has shown to have a much poorer prognosis particularly in septic patients. Probable explanation is pulmonary venous vasoconstriction induced by endotoxemia in sepsis or postcapillary lekocyte aggregation in development of ARDS 2, 4.

One study suggests that although an initial PAD-PWP gradient in patients with sepsis is associated with a high mortality, a much more sensitive indicator is to follow the trend. There was a 91% mortality in patients with persisting or increasing gradients 2.


References: click to get abstract/artice

1. Pulmonary hypertension in sepsis: Measurement by the pulmonary arterial Diastolic-pulmonary wedge pressure gradient and the influence of passive and active factors. Chest 1978; 73:583-91

2. Significance of the pulmonary artery diastolic-pulmonary wedge pressure gradient in sepsis. Crit Care Med 1982; 10:658-61

3. Pulmonary artery diastolic and wedge pressure relationships in critically and injured patients. Arch Surg 1988; 123:933-6

4. Increased Pulmonary Venous Resistance Contributes to Increased Pulmonary Artery Diastolic-Pulmonary Wedge Pressure Gradient in Acute Respiratory Distress Syndrome - Anesthesiology: Volume 102(3) March 2005 pp 574-580