Comparison of Intraoperative versus Postoperative Parathyroid Hormone Levels to Predict Hypocalcemia Earlier after Total Thyroidectomy

Objective To determine differences in the mean parathyroid hormone (PTH) levels for normocalcemic and hypocalcemic total thyroidectomy patients who were tested for PTH during the intraoperative or early postoperative period. Data Sources MEDLINE, the Cochrane Database, and other databases from 1960 to 2014 in the English language and specific to humans for relevant articles. Review Methods Studies were included if PTH was obtained within 24 hours of thyroidectomy. Studies were excluded (1) if only a hemithyroidectomy was performed, (2) if means of studied PTH values were not reported in the article, or (3) if the time of the PTH draw fell outside of defined intraoperative or early postoperative windows. PTH values were divided into 3 groups: preoperative (control group), intraoperative (ie, discharge decisions were based on PTH values drawn in the operating room), and early postoperative (ie, PTH values at 1 to 4 hours after surgery were used as a guide). Results The reported means of perioperative PTH levels and percentage of patients who developed hypocalcemia were collected from 14 studies. PTH evaluated at both the intraoperative and early postoperative periods was significantly lower in patients who became hypocalcemic versus patients who remained normocalcemic. There was no significant difference when PTH was measured intraoperatively or early postoperatively. Conclusion Intraoperative PTH has no significant disadvantage versus early postoperative PTH when used as a clinical guide for discharge after thyroidectomy.