Cortisol and ACTH Measurements at Extubation From Pituitary Surgery Predicts Hypothalamic-Pituitary-Adrenal Axis Function

Abstract

Context: Early prediction of hypothalamic-pituitary-adrenal (HPA) axis function following transsphenoidal surgery (TSS) can improve patient safety and reduce costs. Objective: Systematic measurement of ACTH and cortisol at extubation following anesthesia to predict remission from Cushing's disease (CD) and HPA axis preservation following non-CD surgery. Design: Retrospective analysis of clinical data between August 2015 and May 2022. Setting: Referral center. Patients: Consecutive patients (n = 129) undergoing TSS who had perioperative ACTH and cortisol measurements. Interventions: ACTH and cortisol measurement at extubation. Further serial 6-hourly measurements in CD patients. Main outcome measures: Prediction of future HPA axis status based on ACTH/cortisol at extubation. Results: ACTH and cortisol increased sharply in all patients at extubation. CD patients (n = 101) had lower ACTH values than non-CD patients (110.1 vs 293.1pg/mL; P < 0.01). In non-CD patients, lower plasma ACTH at extubation predicted the need for eventual corticosteroid replacement (105.8 vs 449.1pg/mL, P < 0.01). In CD patients, the peak post-extubation cortisol at 6hours was a robust predictor for nonremission (60.7 vs 219.2μg/dL, P = 0.03). However, normalized early postoperative value (NEPV; the post-extubation values minus the peak preoperative CRH or desmopressin test values) of cortisol reliably distinguished nonremission earlier, at the time of extubation (-6.1 vs 5.9, P = 0.01), and later. Conclusions: We found that at extubation following TSS, ACTH can predict the need for eventual steroid replacement in non-Cushing's patients. In patients with CD, we found a robust prediction of nonremission with NEPV cortisol at extubation and later.