The pituitary-adrenal axis is activated more in non-survivors than in survivors of cardiac arrest, irrespective of therapeutic hypothermia.
OBJECTIVE
To investigate the effect of therapeutic hypothermia in the prognostic value of the pituitary-adrenal axis in comatose patients after cardiac arrest.


METHODS
Prospective observational study in intensive care units (ICU) of a university and an affiliated regional hospital.


METHODS
Twenty-nine consecutive patients, in coma after cardiac arrest, admitted to the ICU and treated by hypothermia.


METHODS
On ICU-admission (T=1), at reaching the target of 32-33 degrees C during therapeutic hypothermia (T=2), at the end of hypothermia (T=3) and 48h later (T=4), plasma adrenocorticotrophic hormone (ACTH), serum cortisol, albumin and corticosteroid-binding globulin (CBG) were measured. A short 250 microg ACTH test was performed at each time-point, except at T=1. The free cortisol index (FCI) and free cortisol calculated by Coolens method were also evaluated.


RESULTS
The ICU mortality was 59%, including withdrawal of life-sustaining treatment in 45% because of negative somatosensory evoked potentials. ACTH and (free) cortisol levels (mean 13.1 pmol/L vs. 6.0 pmol/L and 1250 nmol/L vs. 596 nmol/L, respectively) were higher in non-survivors than in survivors. Levels decreased in time, but the relative difference between outcome groups was maintained until T=4. The cortisol response to ACTH was lower in non-survivors at T=3 (P=0.047) only.


CONCLUSIONS
In comatose patients resuscitated from cardiac arrest, the pituitary-adrenal axis is activated particularly in those dying in the ICU, irrespective of therapeutic hypothermia. Hence, activation of the axis may be a marker of fatal cerebral damage. There is no firm evidence for relative adrenal insufficiency associated with death and a transiently blunted cortisol response to ACTH in non-survivors may be attributed to higher baseline values.
Department of Intensive Care and Institute for Cardiovascular Research, Vrije Universiteit Medical Centre, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
Margriet F C
MF
de Jong
Albertus
A
Beishuizen
Martin J
MJ
de Jong
Armand R J
AR
Girbes
A B Johan
AB
Groeneveld
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000368:Aged; D003128:Coma / Q000097:blood / Q000209:etiology / Q000628:therapy; D003422:Critical Care; D005260:Female; D006323:Heart Arrest / Q000097:blood / Q000401:mortality* / Q000628:therapy*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D010912:Pituitary-Adrenal Function Tests; D010913:Pituitary-Adrenal System / Q000503:physiopathology*; D011237:Predictive Value of Tests; D015996:Survival Rate; D016896:Treatment Outcome
D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone