LAUSR

Abstract Introduction Hypocalcemia is the most frequent complication after thyroidectomy. The aim of this work is to identify biochemical risk factors of hypocalcemia using quick perioperative (pre and post-thyroidectomy) intact parathyroid hormone (PTHi) and postoperative calcemias. Methods In a consecutive series of 310 total thyroidectomies, samples of quick PTHi at the anaesthetic induction and 10 min after surgery, together with serum calcemias every 12 h were obtained. The sensitivity, specificity, positive and negative predictive value are analyzed and related to hypocalcemia. A control group of hemithyroidectomies is also analyzed to compare the effects of surgery on PTH secretion. Results Of the 310 patients, 202 (65.1%) remained normocalcemic and asymptomatic (group A), 108 (34.9%) presented hypocalcemia (Group B), requiring oral calcium (79 symptomatic). After analysis of several cut-off points, combining a PTHr drop gradient of 60% or calcemia inferior to 7.4 mg/dl at 24 h, a sensitivity of 100% is achieved without leaving false negatives. Compared to the control group, there is a significant difference with respect to the post-operative calcemias and PTHr, p  Conclusions Total thyroidectomy affects parathyroid function with evident decrease in rPTH and risk of hypocalcemia. The combination of PTHr decrease of 60% or less than 7.4 mg/dl calcemia at 24 h gives a 100% sensitivity for predicting patients at risk of hypocalcemia.