Prospective study of perioperative factors predicting hypocalcemia after thyroid and parathyroid surgery
ABSTRACT To identify whether perioperative 1,25-dihydroxyvitamin D or parathyroid hormone (PTH) levels will predict the development of hypocalcemia after thyroid and parathyroid surgery.
The study included 103 patients who underwent thyroid or parathyroid surgery between 2002 and 2004, with a comparison of the patients who underwent thyroid lobectomy (TL; n = 34), total thyroidectomy (TT; n = 27), parathyroid adenoma excision (PAE; n = 34), and subtotal parathyroidectomy for hyperplasia (SP; n = 8).
Preoperative 1,25-dihydroxyvitamin D levels, number of patients requiring calcium replacement, and postoperative PTH and calcium levels.
No patients in the TL or PAE group developed postoperative hypocalcemia that required calcium replacement. Six patients (22%) in the TT group and 3 patients (38%) in the SP group required calcium replacement for clinically significant hypocalcemia (P<.001). All patients who required calcium replacement had PTH levels of less than 15 pg/mL (1.6 pmol/L) 8 hours after surgery. Among the patients with postoperative PTH levels of less than 15 pg/mL (1.6 pmol/L) 8 hours after surgery, no patients in the PAE group required calcium replacement, compared with 75% of patients in the TT and SP groups (P<.001). The patients in the TT group had significantly lower postoperative calcium levels than those in the TL (P<.001) or the PAE (P<.005) group. The patients in the TL group reached stable calcium levels significantly earlier than those in the other groups (15.8 hours after surgery; P<.05). There was no relationship between preoperative 1,25-dihydroxyvitamin D levels and postoperative calcium levels.
Preoperative 1,25-dihydroxyvitamin D levels were not predictive of postoperative calcium levels. Patients who undergo PAE or TL are at extremely low risk for requiring calcium replacement. Patients who undergo TT or SP with 8-hour postoperative PTH levels greater than or equal to 15 pg/mL (1.6 pmol/L) are at low risk for developing postoperative hypocalcemia, whereas those with PTH levels less than 15 pg/mL (1.6 pmol/L) have a high risk of developing hypocalcemia.
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ABSTRACT: Intraoperative quick intact parathyroid hormone (iPTH) assay (IOPTH) has become a valuable adjunct in parathyroid surgery reliably predicting cure from hyperparathyroid state. Similarly to parathyroid surgery, the accuracy of the assay in predicting postoperative calcemia after thyroid surgery is related to blood sample timing and the criteria applied with no guidelines widely accepted, so far. This study compares different IOPTH criteria in predicting hypoparathyroidism-related hypocalcemia after thyroid surgery. The study included 200 consecutive patients undergoing total thyroidectomy. Three blood samples for IOPTH were taken in each patient: preoperatively--baseline (BL), at the end of surgery--skin closure (SC), and at 4 h postoperatively (4H). Serum calcium was routinely monitored at 4, 12, 24, 48, and 72 h postoperatively. The incidence and severity of hypocalcemia and related symptoms were matched to IOPTH results. The following criteria were tested: A, greater than 50% drop from BL at SC; B, greater than 70% drop from BL at SC; C, greater than 50% drop from BL at 4H; D, greater than 70% drop from BL at 4H; E, serum iPTH less than 15 pg/ml at SC; F, serum iPTH less than 10 pg/ml at SC; G, serum iPTH less than 15 pg/ml at 4H; H, serum iPTH less than 10 pg/ml at 4H. The accuracy of the tested criteria was calculated in predicting serum calcium level less than 2.0 mmol/l at any point after thyroidectomy. Tested criteria had the following value in predicting serum calcium level less than 2.0 mmol/l after thyroidectomy (sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy, respectively): A (60, 89, 38, 95, and 86%), B (80, 93, 57, 98, and 92%), C (70, 90, 44, 96, and 88%), D (85, 95, 65, 98, and 94%), E (80, 91, 50, 98, and 90%), F (90, 95, 69, 99, and 95%), G (90, 95, 70, 99, and 95%), H (95, 99, 90, 99, and 98%). The criterion of iPTH serum level less than 10 pg/ml at 4 h postoperatively has the highest accuracy in predicting serum calcium level below 2.0 mmol/l after total thyroidectomy when compared with the other criteria.Langenbeck s Archives of Surgery 12/2007; 392(6):693-8. DOI:10.1007/s00423-007-0165-6 · 2.16 Impact Factor
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ABSTRACT: Age, postoperative serum parathormone (PTH) level, and preoperative serum 25-hydroxyvitamin D(3) (25-OHD) level predict postoperative hypocalcemia after total thyroidectomy. Prospective clinical trial. Tertiary referral center. One hundred thirty patients with nontoxic multinodular goiter. Patients were divided into 2 groups according to the postoperative serum calcium level. Group 1 (n = 32) consisted of patients with a postoperative serum calcium level of 8 mg/dL or less, and group 2 (n = 98) consisted of patients with a postoperative serum calcium level higher than 8 mg/dL. The preoperative serum 25-OHD level and preoperative and postoperative serum calcium and PTH levels were determined. The number of patients developing hypocalcemia and prediction of postoperative hypocalcemia by the serum 25-OHD and PTH levels. Hypocalcemia developed in 32 patients (24.6%) (group 1). The preoperative serum 25-OHD level and postoperative serum calcium and PTH levels in group 1 were significantly lower than in group 2 (P = .001). With logistic regression analysis, factors that were predictive of postoperative hypocalcemia included a preoperative serum 25-OHD level less than 15 ng/mL (P < .001; odds ratio, 558.5), a postoperative serum PTH level less than 10 pg/mL (P = .01; odds ratio, 16.4), and being older than 50 years (P = .01; odds ratio, 4.6). Age, a low preoperative serum 25-OHD level, and a low postoperative serum PTH level are significantly associated with postoperative hypocalcemia. The low preoperative serum 25-OHD level was more significant than the low postoperative serum PTH level in the prediction of postoperative hypocalcemia.Archives of surgery (Chicago, Ill.: 1960) 12/2007; 142(12):1182-7. DOI:10.1001/archsurg.142.12.1182 · 4.30 Impact Factor
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ABSTRACT: A 1-hour post-thyroidectomy parathyroid hormone (PTH) level of < or =8 ng/L is predictive of patients who will develop hypocalcemia and guides early supplementation with calcium and vitamin D. However, most hypocalcemic patients fail to meet this criterion. The goal of this study was to determine whether PTH < or = 15 ng/L could be used as a better predictor of hypocalcemia. STUDY DESIGN, SUBJECTS, AND METHODS: This retrospective study involved 270 thyroidectomy patients (2004-2006). PTH and calcium levels, length of admission, supplementation, and rates of hypocalcemia were recorded. Forty-three percent (26/60) of patients developing hypocalcemia met the PTH < or = 8 ng/L cut-off. In contrast, 80% (48/60) of patients developing hypocalcemia had a PTH < or = 15 ng/L. Two point two percent of patients had a 1-hour PTH < or = 15 ng/L and failed to develop hypocalcemia, for a specificity of 97%. A 1-hour PTH cut-off of < or =15 ng/L for prophylactic supplementation should allow the prevention of the majority of cases of hypocalcemia, leading to significant cost savings by shortening hospital stays.Otolaryngology Head and Neck Surgery 02/2008; 138(2):204-8. DOI:10.1016/j.otohns.2007.11.021 · 1.72 Impact Factor