Adrenocortical function during septic shock

To investigate, in patients with severe septic shock, the adrenocortical function assessed by daily plasma cortisol determinations during the first 72 h and by the short synthetic ACTH stimulation test performed within 24 h of the onset of shock. Prospective clinical investigation. Medical intensive care unit in a university teaching hospital. 40 consecutive patients with documented septic shock requiring at least hemodynamic resuscitation and respiratory support. There were no interventions. Basal cortisol concentrations were increased with a mean value of 36.8 micrograms/dl (range 7.9-113). Of the overall cortisol determinations 92% were above 15 micrograms/dl. No statistically significant differences in basal cortisol concentrations were found when survival, type of infection, and positive blood cultures were considered. Patients with hepatic disease had significantly higher cortisol (50.1 (+/- 6.2) micrograms/dl versus 35.9(+/- 3.3) micrograms/dl, p = 0.035) levels compared to other patients. No correlations were found between basal plasma cortisol concentrations and factors such as SAPS, OSF, hemodynamic measurements, duration of shock, and amount of vasopressor and/or inotropic agents. Cortisol concentrations had significant but weak correlation with ACTH levels in survivors (r = 0.4; p = 0.03; n = 28) but not in non-survivors (r = 0.03; p = 0.85; n = 52). Cortisol levels in non-survivors increased significantly from enrollment time to the 72nd hour of the survey (day 1: 38.9(+/- 3.8) micrograms/dl versus day 3: 66.7(+/- 17.1) micrograms/dl; p = 0.046) and were significantly higher than those recorded in survivors. Responses to the short ACTH stimulation test were not significantly different between survivors and non-survivors. According to the different criteria used to interpret the response to the ACTH stimulation test, incidence of adrenocortical insufficiency was highly variable ranging from 6.25-75% in patients with septic shock. Only one patient had absolute adrenocortical insufficiency (basal cortisol level below 10 micrograms/dl; response to the ACTH stimulation test below 18 micrograms/dl). Our data suggest that in a selected population of patients with severe septic shock single plasma cortisol determination has no predictive value. The short ACTH stimulation test performed within the first 24 h of onset shock can neither predict outcome nor estimate impairment in adrenocortical function in patients with high basal cortisol level. Adrenal