Endocrine Abstracts (2011) 26 P15

Interstitial cortisol levels obtained by adipose tissue microdialysis in mechanically ventilated septic patients: correlations with total and free serum cortisol

I Ilias3, I Dimopoulou1, N Nikitas4, M Tzanela1, M Theodorakopoulou1, D A Vassiliadi1, P Kopteridis1, N Maniatis1, Argyris Diamantakis1, Stylianos Orfanos1, Ilias Perogamvros1, U Ungerstedt6, B G Keevil7 & Stylianos Tsagarakis2


1Attikon University Hospital, Athens, Greece; 2Evaggelismos Hospital, Athens, Greece; 3‘Helena Venizelou’ Hospital, Athens, Greece; 4‘Alexandra’ Hospital, Athens, Greece; 5Manchester Academic Health Science Centre, Manchester, UK; 6Karolinska Institute, Stockholm, Sweden; 7University Hospital of South Manchester, Manchester, UK.


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 chromatography–tandem mass spectrometry (only day 2). Statistics were done with Student’s t-test and Pearson’s 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.