Adrenal insufficiency in high-risk surgical ICU patients

Study objectives: To examine the incidence and response to treatment of adr enal insufficiency (AI) in high-risk postoperative patients. Design: Prospective observational case series. Setting: Large urban tertiary-care surgical ICU (SICU). Participants: Adults > 55 years of age who required vasopressor therapy aft er adequate volume resuscitation in the immediate postoperative period. Int erventions: Each patient underwent a cosyntropin (ACTH) stimulation test; a t the discretion of the clinical team, some patients were empirically given hydrocortisone (100 mg IV q8h for three doses) before serum cortisol value s became available. Measurements: Adrenal dysfunction (AD), defined as serum cortisol < 20 <mu> g/dL at all time points, with Delta cortisol (60 min post-ACTH minus baseli ne) of less than or equal to 9 mug/dL; functional hypoadrenalism (FH), defi ned as serum cortisol < 30 <mu>g/dL at all time points or Delta cortisol (6 0 min post-ACTH minus baseline) less than or equal to 9 mug/dL; and AI, as the presence of either AD or FH. Results: 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 adr enal function in 70 patients (67.3%). The absolute eosinophil count was sig nificantly 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 vasop ressors within 24 h. This beneficial effect of hydrocortisone reached stati stical 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). Conclusion: There is a high incidence of AI among SICU patients <greater th an> 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.