15 Years of Experience in Alkaline Phosphatase (ALP)-Based Calcium Replacement Protocol for Postparathyroidectomy Patients with ESKD

Background: Despite routine calcimimetic use, parathyroidectomy (PTx) remains useful. Our prior ALP-based post-PTx calcium replacement protocol preemptively started intravenous (IV) and oral calcium (Ca) in immediate post-PTx patients based on their ALP levels. Ca infusion were run over 12 hours. This reduced incidences of hypocalcemia from hungry bone syndrome (HBS), but patients frequently experienced hypercalcemia from over replacement. Hence, the protocol was amended and audited. Methods: After analyzing initial data from 195 patients (2008-2013), we halved the postoperative day IV Ca infusion time from 12 to 6 hours, maintaining the same Ca concentration. We then performed a clinical audit on patients who had PTx using anonymized patient data from the EMR (2020-2023). Results: Total of 68 cases were identified. Median ALP on day of surgery was 312U/L (163-585). Mean cCa level was 2.41mmol/L±0.21 pre-op and 2.17mmol/L±0.21 post op. Mean cCA level from POD1 to POD7 were 2.29mmol/L±0.33, 2.31mmol/L±0.23, 2.44mmol/L±0.30, 2.47mmol/L±0.35, 2.51mmol/L±0.47, 2.46mmol/L±0.60 and 2.48mmol/L±0.80 respectively. Patients received a mean of 86mls±80 IV 10% Ca gluconate given immediately post surgery. Mean IV Ca given from POD1 to POD7 were 110mls±103, 103mls±82, 91mls±85, 78mls±68, 75mls±66, 75mls±59 and 75mls±57 respectively. We found that patients received 16% less IV Ca with the amended protocol. Mean oral elemental Ca post op from day of surgery to POD 7 were: 1.04g±0.26, 3.10g±0.78, 3.72g±1.2, 3.89g±1.53, 3.93g±1.67, 3.92g±1.60, 4.16g±1.64 and 3.82g±1.85 respectively. (Fig 1) Conclusion: Post-amendment, total IV Ca received post-PTx and hypercalcemia risk were reduced, while not increasing rates of severe hypocalcemia from HBS. Regular clinical protocol audits are required to optimize patient care.Fig 1