Weight Gain and Cardiopulmonary Bypass

Seventy-two consecutive patients undergoing coronary revascularization were divided initially into three groups consisting of those with perfusion time less than or equal to 90 minutes (Group I), those with perfusion time between 90 and 150 minutes (Group II), and those with perfusion time 150 minutes or longer (Group III). The patients having the longest perfusion displayed, as anticipated, the highest weight gain of 4.4 ± 0.6 Kg following cardiopulmonary bypass in contrast to 2.6 ± 0.3 Kg in Group II and 2.1 ± 0.3 Kg in Group I (p < 0.05). This corresponds to a linear progression with increasing weight gain proportional to increasing perfusion time (0.02-0.03 Kg/min of bypass). These same 72 patients were then divided into two groups: Group A having weight gain less than 2.0 Kg and Group B with weight gain of 2.0 or more Kg. Group B showed a significant reduction of 39% in the serum protein level and 28% in serum albumin as compared to the control level. This is significantly different from the 28% reduction in total serum protein and 17% reduction in serum albumin as was noted in Group A, having the shorter bypass interval (p < 0.05). Thus, while the duration of perfusion is primarily responsible for fluid accumulation and weight gain, the low serum protein may serve to accentuate edema formation. Hemodilution and nonpulsatile flow are factors promoting tissue edema during cardiopulmonary bypass