PURPOSE: Serum total cortisol level has been used for the diagnosis of adrenal insufficiency. However, more than 90% of circulating cortisol is protein-bound and this can affect the assessment of adrenal gland reserve in cardiac surgery patients, because the binding protein levels fall substantially during the postoperative acute phase response. To evaluate cortisol levels and their relationship to albumin levels in the context of severe stress and the acute phase response in patients undergoing cardiac surgery and to assess if the cortisol/albumin (C/A) ratio can be used to predict the need for vasopressors postoperatively.
METHODS: Fifty-seven consecutive patients (54% male) were included in this prospective study, from March to May 2006, average age 70 years (ranging from 44 to 89). Patients with history of adrenal insufficiency or on preoperative steroid therapy were excluded. Serum total cortisol, albumin and C/A ratio were obtained on the morning of surgery and 1 hour after surgery. Standard post-operative hemodynamic monitoring was utilized in all patients.
RESULTS: Twenty-eight patients (49%) required vasopressors for 22 hours (ranging from 2 to 48 hours) post cardiac surgery. The serum total cortisol level in this group increased from 16.8 to 32.7 mg/dl, and serum albumin dropped from 3.6 to 2.5 g/dl post operatively. Those 29 patients (51%) who did not receive any vasopressors in the postoperative period had preoperative cortisol and albumin levels of 13.6 mg/dl and 3.9 g/dl, respectively, with the post cardiac surgery levels being 27.3 mg/dl and 2.8 g/dl, respectively.The C/A ratio before surgery was higher in people requiring vasopressors versus patients not requiring pressor support (4.94 vs. 3.48, p< 0.05).
CONCLUSION: Pre cardiac surgery total serum cortisol and albumin levels did not predict the need for postoperative vasopressors, however patients with higher pre surgery cortisol/albumin ratio, required postoperative vasopressors more frequently.A better understanding of the physiology of the adrenal response in the setting of cardiac surgery is needed.
CLINICAL IMPLICATIONS: Patients with higher pre surgery CA ratio, most likely will require vasopressors in post surgical period.
DISCLOSURE: Alexey Amchentsev, No Financial Disclosure Information; No Product/Research Disclosure Information