Risk Factors for Pancreatic Cellular Injury after Cardiopulmonary Bypass

Abstract

Pancreatitis is a known complication of cardiac surgery with cardiopulmonary bypass. Although ischemia is believed to be a factor, the cause of pancreatitis after cardiopulmonary bypass remains unknown. We prospectively studied 300 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass. Serum amylase, pancreatic isoamylase, and serum lipase were measured on postoperative days 1,2,3,7, and 10. Pancreatic cellular injury was defined as the presence of hyperamylasemia (greater than 123 U per liter) with an increase in either the serum level of lipase (greater than 24 U per liter) or the peak level of pancreatic isoamylase. Trypsinogen-activation peptides, which indicate intrapancreatic enzyme activation, were measured in the urine of the last 101 patients studied. Evidence of pancreatic cellular injury was detected in 80 patients (27 percent), of whom 23 had associated abdominal signs or symptoms and 3 had severe pancreatitis (2 with pancreatic abscess and 1 with necrotizing hemorrhagic pancreatitis). Two of 19 postoperative deaths were secondary to pancreatitis. In multivariate analyses, the development of pancreatic cellular injury was significantly associated with preoperative renal insufficiency, valve surgery, postoperative hypotension, and perioperative administration of calcium chloride. The administration of more than 800 mg of calcium chloride per square meter of body-surface area was an independent predictor of pancreatic cellular injury, and the increase in risk was dose-related. No differences were found in the level of trypsinogen-activation peptides between patients who had pancreatic cellular injury and those who did not. Pancreatic cellular injury, as indicated by hyperamylasemia of pancreatic origin, is common after cardiac surgery. The administration of large doses of calcium chloride is an independent predictor of pancreatic cellular injury and may be a cause of it.