Lindblom Pia, Westerdahl Johan, Bergenfelz Anders
Department of Surgery, Lund University Hospital, Lund, Sweden.
Surgery. 2002 May;131(5):515-20. doi: 10.1067/msy.2002.123005.
Selecting patients with a low risk of hypocalcemia is mandatory if patients are to be discharged on the first day after bilateral thyroidectomy. This study investigated the predictive value of intraoperative parathyroid hormone (PTH).
Thirty-eight patients underwent total or near-total thyroidectomy. Patients with or without biochemical and symptomatic hypocalcemia were compared regarding intraoperative PTH levels and previously suggested risk factors. The accuracy of intraoperative PTH to predict patients at risk for postoperative hypocalcemia was compared with a calcium concentration of less than 2.00 mmol/L (8.0 mg/dL) on the first postoperative day.
PTH levels after resection of the second lobe, age, and number of parathyroid glands identified intraoperatively were independently associated with the reduction in serum calcium concentration measured at nadir on the first or second postoperative day. PTH levels after resection of the second lobe were lower among patients who developed biochemical (P <.001) and symptomatic hypocalcemia (P <.01) compared with those who did not. Low levels of intraoperative PTH identified the 3 patients who required intravenous calcium during the first 24 postoperative hours. An intraoperative PTH level below reference range and a calcium concentration of less than 2.00 mmol/L measured 1 day postoperatively both predicted biochemical hypocalcemia with a similar sensitivity (90% vs 90%) and specificity (75% vs 82%). Intraoperative PTH was slightly better than a serum calcium concentration of less than 2.00 mmol/L on postoperative day 1 to predict symptomatic hypocalcemia, with a sensitivity of 71% vs 52% and a specificity of 81% vs 76%, respectively.
Parathyroid gland insufficiency is the main determinant of transient hypocalcemia after bilateral thyroid surgery. Low intraoperative PTH levels during thyroid surgery are therefore a feasible predictor of postoperative hypocalcemia.
如果双侧甲状腺切除术后患者要在术后第一天出院，那么选择低钙血症风险低的患者是必不可少的。本研究调查了术中甲状旁腺激素（PTH）的预测价值。
38例患者接受了全甲状腺切除术或近全甲状腺切除术。比较有或无生化及症状性低钙血症患者的术中PTH水平及先前提出的危险因素。将术中PTH预测术后低钙血症风险患者的准确性与术后第一天钙浓度低于2.00 mmol/L（8.0 mg/dL）进行比较。
切除第二叶后的PTH水平、年龄和术中识别的甲状旁腺数量与术后第一天或第二天最低点时测得的血清钙浓度降低独立相关。与未发生生化性（P<.001）和症状性低钙血症（P<.01）的患者相比，发生生化性和症状性低钙血症的患者切除第二叶后的PTH水平较低。术中PTH水平低识别出了3例术后24小时内需要静脉补钙的患者。术中PTH水平低于参考范围和术后1天测得的钙浓度低于2.00 mmol/L均能以相似的敏感性（90%对90%）和特异性（75%对82%）预测生化性低钙血症。术中PTH在预测症状性低钙血症方面略优于术后第1天血清钙浓度低于2.00 mmol/L，敏感性分别为71%对52%，特异性分别为81%对76%。
甲状旁腺功能不全是双侧甲状腺手术后短暂性低钙血症的主要决定因素。因此，甲状腺手术中低术中PTH水平是术后低钙血症的可行预测指标。
