INFLUENCE OF ELEVATED PULMONARY VASCULAR-RESISTANCE ON RELATIONSHIP BETWEEN CENTRAL VENOUS-PRESSURE AND PULMONARY-ARTERY OCCLUDED PRESSURE FOLLOWING CARDIOPULMONARY BYPASS

This study has demonstrated that CVP measurement is an unreliable index of left ventricular filling pressure in unselected patients undergoing A-C bypass procedures. The influence of altered PVR on the disparity between right and left ventricular filling pressures is not of prime importance. The inconsistent relationship between CVP and PAois primarily a result of ventricular dysfunction and not altered PVR. This suggests that following A-C bypass surgery patients cannot be grouped with respect to altered PVR as the variable which determines whether CVP will be a reliable guide to changes in left atrial pressure. Routine use of Swan-Ganz catheters would improve the precision of monitoring and fluid administration in all patients following CPB. However, it would also increase the cost and complexity of routine care and add a very low incidence of complications to all patients having cardiac surgery. At present, we monitor high risk patients from the time of surgery and advocate early insertion of Swan-Ganz catheters in low risk patients if they are not responding to appropriate management. © 1978 Canadian Anesthesiologists.