Cortisol levels are influenced by sedation in the acute phase after subarachnoid haemorrhage

BACKGROUND: Subarachnoid haemorrhage (SAH) is a life-threatening condition that may be aggravated by acute pituitary damage and cortisol insufficiency. Robust diagnostic criteria for critical illness-related corticosteroid insufficiency (CIRCI) are lacking. The aim of this study was to assess the frequency of CIRCI in the acute phase (0-240 h) after SAH and to evaluate associations between cortisol levels and clinical parameters (sedation, circulatory failure, gender, age, severity of disease, treatment). CIRCI was defined as a single morning serum cortisol (mSC) < 200 nmol/L. The lower limit for calculated free cortisol (cFC) was set at < 22 nmol/L, and for saliva cortisol at < 7.7 nmol/L. METHODS: Fifty patients were included. Serum/saliva cortisol and corticosteroid-binding globulin were obtained every second morning. A logistic regression model was used for multivariate analysis comparing cortisol levels with clinical parameters. RESULTS: Of the patients, 21/50 (42%) had an mSC < 200 nmol/L and 30/50 (60%) had a cFC < 22 nmol/L. In patients with continuous intravenous sedation, the odds ratio for a mSC to be < 200 nmol/L was 18 times higher (95% confidence interval 4.2-85.0, P < 0.001), and the odds ratio for a cFC to be < 22 nmol/L was 2.4 times higher (95% confidence interval 1.2-4.7, P < 0.05) compared with patients with no continuous intravenous sedation. CONCLUSIONS: Continuous intravenous sedation was significantly associated with cortisol values under defined limits (mSC < 200, cFC < 22 nmol/L). The possibility that sedating drugs per se may influence cortisol levels should be taken into consideration before CIRCI is diagnosed.