Study objectives: To examine the incidence and response to treatment of adrenal 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 after adequate volume resuscitation in the immediate postoperative period.
Interventions: 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.
Measurements: 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.
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 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).
Conclusion: 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.