Intraoperative parathormone measurement from the internal jugular vein predicts post-thyroidectomy hypocalcaemia

The most common significant complication of total thyroidectomy is hypoparathyroidism. Intraoperative prediction of which patients are likely to be affected would allow both intraoperative and postoperative interventions to be utilised in these patients. Selection of these patients is essential if we are to be successful at discharging total thyroidectomy patients on the first postoperative day. We investigated the utility of intraoperative parathormone measurement from the internal jugular vein at predicting postoperative hypocalcaemia.

Prospective collection of data was done on 45 consecutive total thyroidectomy patients. Preoperative calcium, intraoperative parathormone and postoperative calcium and parathormone were collected. The accuracy of intraoperative parathormone in predicting those with postoperative hypocalcaemia was assessed.

Intraoperative parathormone of less than 2 pmol l(-1) had a sensitivity of 100% and a specificity of 95% in predicting those with postoperative hypocalcaemia. An intraoperative sample less than 2 pmol l(-1) was a highly significant predictor (p < 0.0001) of postoperative hypocalcaemia.

Intraoperative assessment of parathormone is an accurate predictor of those patients who will become hypoparathyroid in the postoperative period. Intraoperative prediction allows for targeted autotransplantation of glands in those at risk and selected early institution of postoperative supplementation in these patients. Patients not identified as at risk can be safely discharged.