"In the study, researchers tested five aspects of cortisol metabolism in 158 critically ill patients as well as 64 controls. The aspects measured were the participants' levels of urinary cortisol metabolites, daily levels of corticotropin and cortisol, plasma clearance of 100 mg of hydrocortisone, levels of messenger RNA and protein in liver and adipose tissue, and plasma cortisol clearance, metabolism, and production.
As expected, critically ill participants had an 83% higher production of cortisol and lower corticotropin levels when compared to the control group. After looking at the plasma clearance of hydrocortisone and the plasma cortisol clearance, it became evident that participants in the intensive care unit do have reduced cortisol metabolisms. In fact, these participants had 50% less cortisol clearance than the healthy controls."