bilirubin, and is associated with a high mortality. Important contributing factors are the preoperative total bilirubin concentration, preoperative severity of right atrial pressure, numbers of valve replacement procedures, and the amount of blood transfusion requirement during and shortly after surgery. We suggest that postoperative hyperbilirubinemia is a multifactorial process, which is caused by both the impaired liver function of bilirubin transport and the increased production of bilirubin from haemolysis.
INTRODUCTIONIt has long been recognized that early hyperbilirubinemia or transient jaundice could occur after extracorporeal circulation surg er y. According to earlier studies, overall incidence of postoperative hyperbilirubinemia ranges from about 8.6% to even as high as 40% [1][2][3] . Despite improvements in perioperative management, as well as in surgical and anaesthetic techniques, early hyperbilirubinemia after modern extracorporeal circulation surgery is still seen quite often. The high frequency of hyperbilirubinemia after cardiac surgery in our department prompted us to start a prospective study recently. It is aimed to clarify the incidence and nature of postoperative hyperbilir ubinemia in patients following moder n extracorporeal circulation, to analyze possible perioperative risk factors, and to elucidate the clinical significance of postoperative hyperbilirubinemia associated mortality and morbidity. Abstract AIM: To clarify the incidence and nature of postoperative hyperbilirubinemia in patients after modern e x t r a c o r p o r e a l c i r c u l a t i o n , t o a n a l y z e p o s s i b l e perioperative risk factors, and to elucidate the clinical significance of postoperative hyperbilirubinemia associated mortality and morbidity.
MATERIALS AND METHODS
Patients' backgrounds
METHODS: Between March 2005 and May 2006, three hundred and eighty six consecutive patients undergoing extracorporeal circulation surgery due to a variety of cardiac lesions were investigated prospectively. The incidence of postoperative hyperbilirubinemia was defined as a serum total bilirubin concentration of more than 51 μmol/L. Several perioperative parameters w e r e c o m p a r e d b y l o g i s t i c r e g r e s s i o n b e t w e e n hyperbilirubinemia and non-hyperbilirubinemia patients to determine possible risk factors contributing to postoperative hyperbilirubinemia and mortality.
R E S U LT S :O v e r a l l i n c i d e n c e o f p o s t o p e r a t i v e hyperbilirubinemia was 25.3% (98/386). In patients w i t h p o s t o p e r a t i v e h y p e r b i l i r u b i n e m i a , 5 6 . 2 % reached peak total bilirubin concentration on the first postoperative day, 33.5% on the second day, and 10.3% on the seventh day. Eighty percent of the increase of total bilirubin resulted from an increase of both conjugated and unconjugated bilirubin. Development of postoperative hyperbilirubinemia was associated with a higher mortality (P < 0.01), longer duration of mechanical ventilation (P < 0.05) and longer ICU stay ti...