Serum free cortisol index, free cortisol, and total cortisol in critically ill children.
BACKGROUND
In critical illness, serum total cortisol (TC) may not adequately reflect adrenal function because of reduced cortisol-binding globulin (CBG).


OBJECTIVE
To evaluate adrenal function of critically ill children, using free cortisol index (FCI), calculated free cortisol (cFC), and TC levels.


METHODS
Thirty-two critically ill and 36 healthy children were included. All children underwent the 1 microg cosyntropin test. TC and CBG levels were measured. Basal and peak TC, FCI, and cFC were determined.


RESULTS
Basal and peak TC, FCI, and cFC of critically ill children were significantly higher than those of the controls. Compared with TC, both basal and peak FCI and cFC of the patients were higher than those of controls to a greater degree. Use of FCI or cFC to diagnose adrenal insufficiency (AI) reduced the frequency of diagnosis of AI by 50%.


CONCLUSIONS
FCI and cFC better reflect the dynamic changes of adrenal function of critically ill children.
Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Rama 6 Road, Bangkok, 10400, Thailand. rapptv@mahidol.ac.th
Preamrudee
P
Poomthavorn
Rojjanee
R
Lertbunrian
Aroonwan
A
Preutthipan
Arporn
A
Sriphrapradang
Patcharin
P
Khlairit
Pat
P
Mahachoklertwattana
D000293:Adolescent; D002352:Carrier Proteins / Q000097:blood; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003366:Cosyntropin / Q000494:pharmacology; D016638:Critical Illness; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007223:Infant; D015278:Intensive Care Units, Pediatric; D008297:Male; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D011446:Prospective Studies; D013785:Thailand
D002352:Carrier Proteins; C027091:cortisol binding globulin; D003366:Cosyntropin; D006854:Hydrocortisone