Anesthesia and Surgical Factors Linked to Postoperative Low Thyroid Hormone in Children

This retrospective cohort study at Shanghai Children's Medical Center included 233 pediatric patients (ages 0–18) undergoing surgery and anesthesia. The primary outcome was postoperative low thyroid hormone (LTH), defined by free T3 and/or free thyroxine levels below the lower reference limit. The study examined associations between LTH and anesthesia duration, surgical duration, ASA physical status, cardiac surgery, and cardiopulmonary bypass (CPB) use.

Postoperative LTH occurred in 78 of 233 patients (33.5%). Longer anesthesia duration, longer surgical duration, higher ASA physical status (III–V), cardiac surgery, and CPB use were associated with LTH. The study did not report effect sizes, confidence intervals, or p-values for these associations.

Secondary analyses explored links between anesthetic factors and perioperative thyroid hormone changes and between postoperative TH reduction and clinical outcomes in cardiac surgery patients. However, clinical outcomes were analyzed only in the cardiac surgery sub-cohort, and no specific outcome data were reported.

Key limitations include the retrospective design and restriction of clinical outcome analysis to a cardiac surgery sub-cohort. The study explicitly notes that it describes associations; causality is not claimed. Safety and tolerability data were not reported.

In practice, these results suggest that children undergoing longer procedures, higher ASA status, cardiac surgery, or CPB may be more likely to experience postoperative LTH. Clinicians should interpret these findings cautiously and await prospective validation before changing monitoring or treatment strategies.