Central venous pressure and pulmonary wedge pressure. A comparative study in anesthetized surgical patients.

To determine the reliability of central venous pressure (CVP) as a guide to fluid therapy during an operation, repeated and simultaneous CVP and pulmonary wedge pressure (PWP) measurements were made with a Swan-Ganz catheter in 13 relatively elderly patients without obvious cardiac or respiratory disease- Overall correlation between CVP and PWP was highly significant (P less than .001); there was, however, an important variation of the correlation for each patient. For values of CVP greater than or equal to 8 mm Hg, the correlation was not significant. The disparity between right and left ventricular filling pressures was confirmed by the relationship between serial changes in CVP and PWP. These data strongly suggest that in relatively elderly patients undergoing surgery without evidence of cardiac or respiratory disease, CVP may be misleading index for appreciating PWP.