Influence of prolonged cardiopulmonary bypass times on splanchnic perfusion and markers of splanchnic organ function

Background Cardiopulmonary bypass (CPB) is known to have considerable negative impact on perfusion and organ function. The effects of the duration of CPB on markers of splanchnic organ function was studied. Methods Consecutive patients undergoing elective aorto-coronary bypass grafting with CPB times (CPBT) of either less than 70 minutes (n = 15) or more than 80 minutes (n = 15) were prospectively studied. Splanchnic perfusion was assessed by measuring arterial and gastric mucosal P 2and calculating P 2gap. Hepatic function was evaluated by monoethylglycinexylidide (MEGX) test and by measuring α-glutathione S-transferase (α-GST). Concentration of pancreatitis-associated protein was measured to assess pancreatic integrity. Measurements were performed after induction of anesthesia, at the end of surgery, 4 hours after arrival in the intensive care unit, and on postoperative day 1. Results The mean (± standard deviation) CPBT were 54 ± 12 minutes and 99 ± 16 minutes, respectively. P 2gap increased significantly more in the group with CPBT of more than 80 minutes than in that with CPBT of less than 70 minutes, at +15 ± 4 mm Hg versus +8 ± 3 mm Hg, respectively, indicating reduction in splanchnic perfusion by longer CPBTs. Postoperative MEGX concentrations were significantly lower and postoperative α-GST concentrations were significantly higher in the group with CPBT of more than 80 minutes than in that with CPBT of less than 70 minutes. Plasma levels of pancreatitis-associated protein remained similar in both groups throughout the study period. Conclusions In our patients with CPBT of more than 80 minutes, splanchnic perfusion and hepatocelluar integrity were moderately affected, whereas pancreatic function remained almost unchanged. Studies including a larger patient population are necessary to assess whether protective approaches would be helpful in patients undergoing complex cardiac surgery with very long CPBT.