Intraoperative parathyroid hormone measurement during parathyroidectomy for treatment of primary hyperparathyroidism: When should you end the operation?

INTRODUCTION: The study objective was to evaluate the intraoperative 50% decrease in PTH level ± PTH normalization for its accuracy and efficiency in predicting cure during parathyroidectomy (PTx) for the treatment of primary hyperparathyroidism (PHP). METHODS: A retrospective review of patients undergoing PTx was conducted. The timepoints at which the 50% PTH decrease was reached were recorded. The accuracy of intraoperative PTH for predicting cure, defined as normocalcemia at 6 months postoperatively, was evaluated. RESULTS: The study population was made up of 248 PHP patients, with 247 patients achieving normocalcemia at 6 months postoperatively. If a 50% PTH decrease was used to indicate operation conclusion, 1 patient would not be cured. Persistent PTH elevation above normal range at T10 had a PPV of 77%, NPV of 99.5%, sensitivity of 95.2% and specificity of 97.3% for predicting the presence of a contralateral pathological parathyroid gland. For the study cohort, 24.5 h of cumulative operating time would be saved if the 50% PTH decrease triggered operation conclusion. DISCUSSION: A decrease in the pre-excision PTH level to 50% of the baseline level, or a decrease in the higher of the baseline or pre-excision PTH levels by 50% at 5 or 10 min post pathological parathyroid gland removal, regardless of whether the PTH level normalizes, reliably predicts cure from PHP and should be used to guide the surgeon during parathyroidectomy.

Outcomes of post-cardiac surgery patients with persistent hyperlactatemia in the intensive care unit: a matched cohort study.

BACKGROUND: Higher morbidity and mortality rates are seen amongst patients presenting with hyperlactatemia in the postoperative period. The purpose of this study was to determine the relationship between persistent elevations in lactate and poor ICU outcome in post-cardiac surgery patients. METHODS: This was a retrospective matched cohort analysis of cardiac surgery patients undergoing bypass and/or valve surgery in a university hospital centre. Selection criteria were: cardiac bypass and/or valve surgery; admission to the ICU for > 24 h postoperatively; and peak lactate ≥ 3.0 mmol/L. Hyperlactatemic patients were matched to 2 normolactatemic patients. Multivariable conditional logistic regression was used to determine predictors of hyperlactatemia and mortality. RESULTS: Four hundred sixty-nine post-cardiac surgery patients were admitted to the ICU for > 24 h. 144 of these patients had an arterial blood lactate ≥ 3.0 mmol/L. Amongst the mortalities, 78.9 % presented with hyperlactatemia. Independent risk factors predictive of a lactate ≥ 3.0 mmol/L were preoperative IABP insertion (RR 2.8, CI 1.1-7.2) and postoperative acute kidney injury (RR 3.2, CI 2.1-5.4). Patients whose lactate concentrations continued to increase >30 h postoperatively were more likely to die (RR 8.44 CI 2.50-28.53). CONCLUSIONS: The persistence of hyperlactatemia is a more important determinant of postoperative outcome than the absolute value of the peak lactate concentration. A simple postoperative lactate washout does not sufficiently explain this lactate accumulation. Mortality is proposed to be secondary to a state of ongoing hypoperfusion.