Early postoperative plasma calcium concentration as a predictor of the need for calcium supplement after parathyroidectomy.

This study evaluated early postoperative serum calcium concentration as a predictor of hypocalcaemic symptoms and the need for calcium supplements. A total of 64 consecutive patients undergoing curative parathyroidectomy for primary hyperparathyroidism were studied. Twenty patients (31 per cent) developed hypocalcaemic symptoms requiring calcium supplements. Plasma calcium levels in the preoperative and early postoperative periods were similar in patients who required calcium supplements and those in whom they were not necessary. There was no significant difference in the percentage decrease in early calcium levels after operation between the two groups. In those undergoing reoperative surgery and subtotal parathyroidectomy the percentage decline was significantly higher in patients who required calcium supplements (12.8 versus 5.6 per cent, P < 0.005). A fall of 10 per cent or more was consistently followed by hypocalcaemic symptoms. Calcium determination in the early postoperative period is of little value in predicting the onset of hypocalcaemic symptoms.