A CHARACTERIZATION OF HYPOTHALAMIC-PITUITARY-ADRENAL AXIS FUNCTION DURING AND AFTER HUMAN CARDIAC-ARREST

Objective: This study characterizes hypothalamic-pituitary-adrenal axi s function during cardiopulmonary arrest and after return of spontaneo us circulation. Design: Prospective case series. Setting. A large urba n emergency department and intensive care unit over an 8-month period. Patients: Two hundred five adult patients presenting in cardiopulmona ry arrest to an urban emergency department. Three patients known to be taking corticosteroids were excluded from the study. Measurements and Main Results: Cortisol concentrations were measured before and after advanced cardiac life support and for five consecutive hours after ret urn of spontaneous circulation. Adrenocorticotropic hormone (ACTH) con centrations were measured before advanced cardiac life support and whe n the cosyntropin stimulation tests were performed 6 and 24 hrs after the return of spontaneous circulation. The mean initial serum cortisol concentration was 32.0 +/- 33.1 mug/dL (882.9 +/- 913.2 nmol/L). Fift y-three percent of patients had cortisol concentrations of <20 mug/dL (<552 nmol/L) at the end of cardiac arrest. Among 44 patients who achi eved return of spontaneous circulation, 98% had initial cortisol conce ntrations of >10 mug/dL (>276 nmol/L) and 73% of patients had initial cortisol concentrations of >20 mug/dL (>552 nmol/L). Mean serum cortis ol concentrations increased significantly (p = .0001) from 1 to 6 hrs after return of spontaneous circulation and decreased significantly (p = .03) from 6 to 24 hrs. A serum cortisol concentration of <30 mug/dl (<828 nmol/L) was associated with a 96% and 100% mortality rate at 6 and 24 hrs, respectively. Mean ACTH concentrations were increased with out a significant difference between the initial and 6-hr concentratio ns. Mean ACTH concentrations decreased between 6 and 24 hrs (p = .06). There were no significant responses to the cosyntropin stimulation at 6 and 24 hrs. Conclusions: Cortisol concentrations after out-of-hospi tal cardiac arrest are lower than those concentrations reported in oth er stress states. There is an association between cortisol concentrati ons and short-term survival after cardiac arrest. Survivors have a sig nificantly greater increase in serum cortisol concentrations than nons urvivors during the first 24 hrs. Lower than expected cortisol concent rations for the extreme stress of cardiac arrest may have pathologic s ignificance in the hemodynamic instability seen after return of sponta neous circulation. The etiology of the low cortisol concentrations may be primary adrenal dysfunction.