Abstract

Background: The management of hypocalcemia after total thyroidectomy (TTx) is a challenge as TTx is transitioned into a same-day surgery. Measurement of parathyroid hormone (PTH) level following TTx may allow prediction of postoperative hypocalcemia, decrease the need for routine calcium (Ca) monitoring and lead to shorter hospital stays. Methods: Protocol based PTH measurement and routine oral Ca supplementation was instituted in 2010 and a prospective database was queried between 2010 and 2011 with 67 patients with TTx identified. Patient demographics; extent of surgery; post operative laboratory values and cost; complications; intravenous Ca; and length of stay were analyzed. Results: Of the 67 patients undergoing TTx, 6 were completion lobectomies. 27 patients (40.2%) carried a preoperative cancer, while Graves disease accounted for 20 (29.8%). Transient hypocalcemia (TH) and permanent hypocalcemia was reported in 8 patients and 1 patient, respectively (11.9%, 1.4%). While neither the diagnosis of cancer nor the extent of central neck dissection impacted the risk of TH (p=0.23 and p=0.67, respectively), the diagnosis of Graves was associated with TH (p=0.002). Post operative PTH was recorded in 49 patients (74.6%); 33 (68%) >10 and 16 (32%) <10. PTH<10 showed a correlation with symptomatic TH (p=0.0006). The relative risk of intravenous Ca with PTH<10 was 6.25 (n=4) (p=0.03). The average length of stay was 1.8 (+/- 2.78 days); PTH<10 group was 3.06 (+/-4.37) and PTH > 10 group was 1.6 (+/-2.45) (p=0.16). Medicare cost of PTH and Ca is $54.46 and $7.30, respectively. In 68% of patients, when PTH >10, an additional cost of $26.25 was incurred with measuring PTH, however this potentially avoids 3.8 lab draws per patient. Conclusions: PTH<10 serves as both a sensitive (100%) and specific (76.7%) predictor of post-operative hypocalcemia. A single PTH check avoids multiple venopunctures with an incurred lab cost, but may lead to additional cost savings if same-day discharge is implemented based upon risk stratification with PTH.