Postoperative Serum Amylase Levels and the Mean Arterial Pressure During Cardiopulmonary Bypass: An Observational Study

Background: Postoperative gastrointestinal complications are important in that they lead to increased lengths of hospitalization in the intensive care unit (ICU) and mortality among patients undergoing surgery on cardiopulmonary bypass (CPB). It appears that such gastrointestinal complications may be correlated with the postoperative serum level of amylase among patients. We aimed to determine the relationship between the mean arterial pressure (MAP) during CPB and changes in the postoperative serum level of amylase. Methods: In this observational study, 164 adult patients who underwent cardiac operations and were transferred into the ICU of Rajaie Cardiovascular Medical Research Center (Tehran, Iran) were enrolled via convenience sampling. The patients’ demographic and clinical data, as well as hemodynamic parameters including MAP, were measured during and after CPB in the ICU. Serum amylase levels were assessed after anesthesia induction, after CPB, 12 and 24 hours after CPB. Results: The mean serum level of amylase significantly increased after CPB and continued 24 hours after ICU admission. There was no statistically significant relationship between MAP during CPB and the serum amylase level immediately after CPB and at 12 and 24 hours after ICU admission. A significant relationship was found between gender and age and a serum level of amylase of greater than 125 IU/L at 12 and 24 hours after CPB. Conclusions: The serum level of amylase increased after CPB up to 24 hours following ICU admission. There was no significant relationship between MAP during CPB and the serum amylase level after cardiac surgery.