OR11-4 Effect of Tight Glycemic Control on Thyroid Function after Pediatric Cardiac Surgery

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: OR11-Pediatric Endocrinology
Clinical
Saturday, June 15, 2013: 11:30 AM-1:00 PM
Presentation Start Time: 12:15 PM
Room 104 (Moscone Center)
Carmen L Soto-Rivera*1, Lisa A Scoppettuolo1, Jamin Alexander1, Alexandra Oldershaw1, David Wypij2, Michael G Gaies3 and Michael S D Agus1
1Boston Children's Hospital, Boston, MA, 2Harvard School of Public Health, Boston, MA, 3University of Michigan's C.S. Mott Children's Hospital, MI
Background: There are expected alterations in thyroid function after pediatric cardiopulmonary bypass (CPB) that are associated with prolongation of recovery. Thyroid changes in the setting of tight glycemic control (TGC) after pediatric cardiac surgery have not been described in the setting of a trial with a low hypoglycemia rate. We tested the hypothesis that TGC would be associated with earlier normalization of thyroid function compared with standard care (STD), or permissive hyperglycemia, in children undergoing cardiac surgery.

Methods: In this two-center, prospective, randomized trial, we studied 980 children, birth to 36 months of age, undergoing cardiac surgery with CPB. Patients were randomly assigned to either TGC or STD in the cardiac intensive care unit. Thyroid stimulating hormone (TSH), total thyroxine (T4), total triiodothyronine (T3) and thyroid hormone binding ratio (THBR) were obtained on post-operative days (POD) 2, 7 and 14 for subjects in both groups. All hormones were assayed by electrochemiluminescent immunoassay. Subjects having at least one pair of POD 2-7 or POD 2-14 values were studied.

Results: 260 patients were still on study on POD 7, of which 191 patients (99 TGC, 92 STD) had thyroid function data through POD 7 and 67 (30 TGC, 37 STD) through POD 14. The great majority of patients had POD 2 values that were lower than age-specific normal ranges for T4 (98%), T3 (98%), and TSH (85%), while 76% patients were within normal range for THBR. Values on POD 2 were similar for both groups (all p>0.20). By POD 7, the TGC group had higher T4 [median 6.4 (interquartile range 4.4-9.0) vs 5.3 (4.1-7.1) mcg/dL, p=0.02] and a greater change from POD 2 [2.4 (0.2-4.3) vs 1.3 (−0.2-2.8) mcg/dL, p=0.02] compared with the STD group. By POD 14, the TGC group had higher T3 [104.5 (79-137) vs 74 (60-112) ng/dL, p=0.02] and a greater change from POD 2 [26 (9-68) vs 5 (−10-42) ng/dL, p=0.02] compared with the STD group. There was no difference in TSH or THBR between groups at POD 7 or POD 14.

Conclusion: TGC resulted in earlier normalization of thyroid hormone concentrations in children who are post-operative from cardiac surgery with CPB. This finding differs from previous reports of TGC increasing peripheral inactivation of thyroid hormone mimicking a fasting response, which could be related to the very low rates of hypoglycemia in our cohort. Our findings are specific for pediatric cardiac surgery patients and the impact of TGC on other critically ill children warrants further investigation.

Disclosure: MSDA: Consultant, Roche Diagnostics, Consultant, Medtronic Minimed. Nothing to Disclose: CLS, LAS, JA, AO, DW, MGG

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm