Aim: To measure interstitial cortisol obtained by adipose tissue microdialysis (MD) as well as serum total and free cortisol in 31 mechanically ventilated patients upon sepsis onset (days 1 and 2). MD tissue glucose, pyruvate, lactate, and glycerol were also measured (as markers of altered or disrupted local energy production).
Methods: The Acute Physiology and Chronic Health Evaluation (APACHE II) on day 1 and the sequential organ failure assessment (SOFA) scores were calculated for all the patients. MD cortisol was determined with enzyme immunoassay, serum total cortisol was measured with immunochemiluminescence and free serum cortisol was measured with liquid chromatographytandem mass spectrometry (only day 2). Statistics were done with Students t-test and Pearsons correlation coefficient (statistical significance was set at P<0.05).
Results: Serum total cortisol and cortisol measurements in the interstitial fluid obtained with MD remained fairly constant. On day 2 mean serum free cortisol was 2.052±1.769 μg/dl (n=16); serum free cortisol was higher than MD (free) cortisol on day 2 (P=0.010). Serum free cortisol on day 2 (for n=16) correlated well with serum total cortisol (r: +0.879, 95% CI: +0.721 to +0.950, P<0.0001) and MD cortisol (r: +0.863, 95% CI: +0.654 to +0.949, P<0.0001). There were also significant correlations between interstitial MD cortisol and APACHE II, SOFA and MD pyruvate levels.
Conclusions: Interstitial cortisol measurements represent an additional tool to investigate the adrenal axis in septic, critically ill patients. In these patients tissue cortisol availability, as reflected by cortisol levels obtained by adipose tissue MD, correlates well with total and free serum cortisol levels.
30 Apr - 04 May 2011
European Society of Endocrinology