THYROID-FUNCTION IN INFANTS FOLLOWING CARDIAC-SURGERY - COMPARATIVE EFFECTS OF IODINATED AND NONIODINATED TOPICAL ANTISEPTICS

Objectives: Cardiopulmonary bypass has profound effects on thyroid hor mone metabolism. These effects may be exacerbated in infants because t hey are able to absorb large quantities of iodine transcutaneously. Th e purpose of this study was to test the hypothesis that preoperative p ovidone iodine contributes to postoperative thyroid depression in infa nts who undergo cardiac surgery. Design: Prospective, randomized, cont rolled trial. Setting: Children's Hospital and Medical Center, Seattle , WA. Patients: Thirty-seven infants undergoing repair of congenital c ardiac defects. Interventions: Infants requiring cardiopulmonary bypas s were divided into two groups: Group 1 received povidone-iodine; grou p 2 received chlorhexidine as a topical preoperative antiseptic. Group 3 did not require cardiopulmonary bypass for repair of cardiac defect s and received povidone-iodine as a preoperative antiseptic. Measureme nts and Main Results: Thyrotropin (TSH), total triiodothyronine (T-3), and thyroxine (T-4) were measured at four intervals: a) before prepar ation for surgery; b) immediately after surgery; c) at 2 days after su rgery; and d) at 5 to 8 days after surgery. There was a significant de crease in TSH concentrations immediately after surgery in the two bypa ss groups. This change was significantly greater than in the change in TSH concentration in the thoracotomy group. Total T-3 and T-4 concent rations decreased by postoperative day 2 in both groups 1 and 2, and t he changes were significant compared with group 3. Total T-3 and T-4 c oncentrations increased significantly in all groups after postoperativ e day 2, with no significant difference between the three groups. Conc lusion: Cardiopulmonary bypass has a more significant effect on thyroi d hormone metabolism than does the preoperative antiseptic.