[Modifications in intact parathyroid hormone, total serum calcium, and ionized calcium levels in the surgery of primary hyperparathyroidism for single adenoma].

INTRODUCTION

We evaluated total serum calcium (TSC) and ionized calcium (IC) and their correlation with intraoperative intact parathyroid hormone (iPTH) in the surgery of primary hyperparathyroidism in patients with a single adenoma.

MATERIAL AND METHOD: We performed a prospective, blind trial with determination of iPHT, TSC and IC in a cohort of surgical patients (n = 279; 244 were valid for the study) who underwent surgery in the Department of Surgery, Hospital de Cruces, between October 1999 and April 2006. Total calcium, ionic calcium and iPTH were measured in the outpatient department, on admission and intraoperatively (at anesthesia induction and every 5 minutes after surgical excision).

RESULTS

Levels of calcium and iPTH were corrected in 234 (95.9%) patients. iPTH decreased from abnormal preoperative values of 294.43 +/- 286.38 pg/ml to 97.89 +/- 121.01 mg/dl (minute 5), 58.58 +/- 58.37 pg/ml (minute 10), 44.62 +/- 54.77 pg/ml (minute 15), and 38.42 +/- 51.72 pg/ml (minute 20). TSC decreased from preoperative values of 10.93 +/- 1.04 mg/dl to 10.2 +/- 0.97 mg/dl (minute 5), 10.17 +/- 1.00 mg/dl (minute 10), 10.12 +/- 0.98 mg/ml (minute 15), and 10.09 +/- 1.03 mg/ml (minute 20). The results for ionized calcium were as follows: 4.90 +/- 0.63 mg/dl at induction, 4.84 +/- 0.61 mg/dl (minute 5), 4.84 +/- 0.66 mg/dl (minute 10), 4.82 +/- 0.63 mg/dl (minute 15), and 4.82 +/- 0.63 mg/dl (minute 20). Frozen samples were conclusive for parathyroid tissue (19.56 +/- 15.3 after excision).

CONCLUSIONS

Intraoperative total calcium levels may help to predict adequate elimination of parathyroid tissue in primary hyperparathyroidism when intraoperative iPTH is not available. Ionized calcium levels did not show the same decrease.