Adrenal insufficiency in high-risk surgical ICU patients

To examine the incidence and response to treatment of adrenal insufficiency (AI) in high-risk postoperative patients.

Prospective observational case series.

Large urban tertiary-care surgical ICU (SICU).

Adults > 55 years of age who required vasopressor therapy after adequate volume resuscitation in the immediate postoperative period.

Each patient underwent a cosyntropin (ACTH) stimulation test; at the discretion of the clinical team, some patients were empirically given hydrocortisone (100 mg IV q8h for three doses) before serum cortisol values became available.

Adrenal dysfunction (AD), defined as serum cortisol < 20 microg/dL at all time points, with Delta cortisol (60 min post-ACTH minus baseline) of < or = 9 microg/dL; functional hypoadrenalism (FH), defined as serum cortisol < 30 microg/dL at all time points or Delta cortisol (60 min post-ACTH minus baseline) < or = 9 microg/dL; and AI, as the presence of either AD or FH.

One hundred four patients were enrolled with a mean age (SD) of 65.2 +/- 16.9 years. AI (AD plus FH) was found in 34 of 104 patients (32.7%): AD was found in 9 patients (8.7%), FH in 25 patients (24%), and normal adrenal function in 70 patients (67.3%). The absolute eosinophil count was significantly higher in the combined AD and FH groups compared with the group with normal adrenal function (p < 0.05). Forty-six of 104 patients (44.2%) received hydrocortisone; 29 (63%) could be weaned from treatment with vasopressors within 24 h. This beneficial effect of hydrocortisone reached statistical significance in the FH group when compared with untreated patients (p < 0.031); a similar trend was seen in the AD group (p = 0.083). Mortality was also lower in the hydrocortisone-treated AI patients (5 of 23 [21%] vs 5 of 11 [45%] in those not receiving hydrocortisone; p < 0.01).

There is a high incidence of AI among SICU patients > 55 years of age with postoperative hypotension requiring vasopressors. There is also a significant association between hydrocortisone replacement therapy, resolution of vasopressor requirements, and improved survival.