The relationship between central venous pressure and pulmonary capillary wedge pressure during aortic surgery

Publisher Website
Google Scholar
Abstract
Twenty-three ASA physical status II-III patients scheduled for elective abdominal aortic surgery were studied preoperatively with multiple unit gated acquisition angiography (MUGA) scan to determine the resting left ventricular and right ventricular ejection fractions (LVEF and RVEF respectively). lntraoperatively pulmonary capillary wedge pressure (PCWP) and central venous pressure (CVP) were measured in each patient at five different time periods in the horizontal, 24° head up, and 24° head down table tilt positions. The correlation between absolute values and changes in PCWP and CVP, and the degree to which preoperative knowledge of LVEF and RVEF predicted these correlations were examined. Resting LVEF ranged from 0.1 to 0.84. Thirteen of the 23 patients failed to show significant correlation (p < 0.05) between the absolute values of PCWP and CVP either before and/or after aortic crossclamp. When the correlation coefficients from this analysis were ranked against LVEF, there was a weak but significant correlation before aortic crossclamp (r = 0.41), but not after. The correlation between a change in PCWP and a change in CVP was significant for the 23 patients at all lime intervals, before and after aortic crossclamp. However, the prediction of a change of PCWP value from a known change of CVP value ranged in accuracy from ± 3 mmHg to ± 12.5 mmHg. The study suggests that if the filling pressures of both ventricles need to be assessed during aortic surgery, then the PCWP and CVP must be independently measured. Preoperative knowledge of LVEF and RVEF as determined by MUGA scan did not identify a subgroup of patients in whom PCWP and CVP correlated consistently throughout aortic surgery.