1. Cooper MS, Stewart PM. Corticosteroid insufficiency in acutely ill patients. N Engl J Med. 2003. 348:727–734.

2. Marik PE, Pastores SM, Annane D, Meduri GU, Sprung CL, Arlt W, Keh D, Briegel J, Beishuizen A, Dimopoulou I, Tsagarakis S, Singer M, Chrousos GP, Zaloga G, Bokhari F, Vogeser M. Recommendations for the diagnosis and management of corticosteroid insufficiency in critically ill adult patients: consensus statements from an international task force by the American College of Critical Care Medicine. Crit Care Med. 2008. 36:1937–1949.

3. Arafah BM. Hypothalamic pituitary adrenal function during critical illness: limitations of current assessment methods. J Clin Endocrinol Metab. 2006. 91:3725–3745.

4. Kim KW, Kim SW, Kim HJ, Shin CS, Park SJ, Suh GJ, Kim SY. No significance of the free cortisol index compared to total cortisol in critically ill patients. Endocrinol Metab. 2011. 26:120–125.

5. Sweeney DA, Natanson C, Banks SM, Solomon SB, Behrend EN. Defining normal adrenal function testing in the intensive care unit setting: a canine study. Crit Care Med. 2010. 38:553–561.

6. Ho JT, Al-Musalhi H, Chapman MJ, Quach T, Thomas PD, Bagley CJ, Lewis JG, Torpy DJ. Septic shock and sepsis: a comparison of total and free plasma cortisol levels. J Clin Endocrinol Metab. 2006. 91:105–114.

7. Bendel S, Karlsson S, Pettila V, Loisa P, Varpula M, Ruokonen E. Free cortisol in sepsis and septic shock. Anesth Analg. 2008. 106:1813–1819.

8. Arlt W, Hammer F, Sanning P, Butcher SK, Lord JM, Allolio B, Annane D, Stewart PM. Dissociation of serum dehydroepiandrosterone and dehydroepiandrosterone sulfate in septic shock. J Clin Endocrinol Metab. 2006. 91:2548–2554.