Hypoalbuminemia following Abdominal Surgery Leads to High Serum Unbound Bilirubin Concentrations in Newborns Soon after Birth

Abstract

BACKGROUND: The serum concentration of unbound bilirubin (UB), which is bilirubin not bound to albumin (Alb), is a better index than total bilirubin concentration (TB) for identifying infants at risk for developing bilirubin neurotoxicity. The degree to which the hypoalbuminemia following abdominal surgery in jaundiced newborns affects bilirubin binding is unknown. OBJECTIVE: To determine whether lower Alb occurring in newborns undergoing abdominal surgery shortly after birth results in significantly higher UB in serum versus nonsurgical patients at comparable serum TB. METHODS: A matched case-control study was conducted with term and late-preterm newborns. The surgery group included 15 newborns who underwent abdominal operation within 3 days after birth. Clinical and laboratory data (serum UB, TB, and Alb concentrations, UB/TB ratio, and binding constant) in the surgery group were collected and compared with those of 30 control newborns who did not undergo abdominal surgery (control group). RESULTS: Serum UB and the UB/TB ratio in the surgery group were significantly higher than those in the control group (p < 0.02, p < 0.001, respectively), whereas there were no significant differences in serum TB and binding constant between the groups. Serum Alb concentrations in the surgery group were significantly lower than those in the control group (p < 0.001). When pre- and postoperative serum Alb concentrations were compared, there was a significant decrease from 3.4 to 2.7 g/dl (p < 0.001). CONCLUSIONS: Our study suggests that hypoalbuminemia following abdominal surgery causes a higher serum UB at comparable serum TB in newborns.