Transphenoidal surgery without steroid replacement in patients with morning serum cortisol below 9 μg/dl (250 Nmol/l)

Adrenal insufficiency is a feared complication in patients undergoing transphenoidal surgery (TSS). Using the insulin tolerance test (ITT) for the preoperative assessment of hypothalamic-pituitary-adrenal (HPA) status is less than ideal, and the morning serum cortisol (MSC) is often used as a proxy for ITT. However, neither the ITT nor the MSC level has been validated to indicate HPA sufficiency compared to a physiological gold standard such as patients' ability to withstand transphenoidal surgery.

To evaluate the intraoperative and postoperative course of nine patients with non-ACTH-secreting pituitary adenomas who did not receive intraoperative cortisol replacement despite having a preoperative MSC below 9 μg/dl (250 nmol/l) and to compare this with a set of patients with a preoperative MSC greater than 14.5 μg/dl (400 nmol/l) and another set of patients with MSC below 9 μg/dl (250 nmol/l) who received intraoperative cortisol administration.

Preoperative and day 1 and day 2 postoperative MSC, intraoperative anesthetic record, vital signs, fluid balance, medications, and complications were recorded.

None of the patients experienced the full syndrome of adrenal insufficiency. One patient with a preoperative MSC <9 μg/dl (250 mol/l) had isolated postoperative fatigue and required cortisol replacement. No patient suffered any life-threatening complications. There were no differences among the three groups in their intraoperative or postoperative courses when compared for intraoperative hypotension, acute blood pressure drop, and administration of vasopressors.

This study suggests that TSS can be performed safely in patients with preoperative MSC less than 9 μg/dl (250 nmol/l) in closely monitored settings without intraoperative cortisol administration. Further studies are warranted.