Neuroendocrine and cardiovascular changes in septic shock and after cardiac surgery: effect of high-dose corticosteroid therapy.

Plasma levels of beta-endorphin-like immunoreactivity (BLI) were similarly elevated in patients with septic shock (group A) and in normotensive subjects recovering from cardiac surgery (group B) (1231 +/- 483 pg ml-1 and 1,240 +/- 355 pg ml-1, respectively). In neither group was cardiac output reduced, but total peripheral resistance index (TPRI) was low in group A and low or normal in group B. Intravenous methylprednisolone (MP) 30 mg kg-1 variably suppressed BLI by a mean of only 30% in group A, while in group B, BLI usually rose and then fell following MP. In group A percentage changes in BLI were positively correlated with percentage changes in cardiac index (CI) and mean arterial pressure (MAP) (r = .83, P less than .01, r = .59, P less than .05 respectively). No such correlations were found in group B. These findings suggest that increases in circulating beta-endorphin are unlikely to be responsible for myocardial depression or hypotension in septic shock. ACTH levels were in general normal in group A but were consistently elevated in group B, although plasma cortisol was similarly elevated in both groups. Furthermore there was a good correlation between percentage changes in ACTH and BLI following MP in group B (r = .87, P less than .01) but not in group A. Possible explanations for these findings are discussed.