High endogenous melatonin levels in critically ill children: a pilot study.
OBJECTIVE
To evaluate the serum melatonin levels in critically ill pediatric patients and to test the effect of light on the melatonin's circadian rhythm. Data on melatonin secretion in critically ill pediatric subjects are lacking.


METHODS
We investigated the serum melatonin levels of 16 sedated and mechanically ventilated patients in a pediatric intensive care unit. Children (mean age, 5.1 ± 3.1 years) were randomly assigned to a dark-exposed or to a light-exposed group to evaluate the effects of light on serum melatonin concentrations. Blood samples for serum melatonin analysis were collected at 10 p.m., 1 a.m., 3 a.m., 5 a.m., 8 a.m., and 12 p.m.


RESULTS
The melatonin circadian rhythm was severely disrupted in critically ill children; light exposure lowered serum melatonin even in a context of highly altered circadian cycle; melatonin peaks were greater for healthy age-matched children.


CONCLUSIONS
The high melatonin levels in the critically ill children may be a response to counteract the elevated oxidative stress associated with serious diseases. Whether these elevated melatonin levels confer any beneficial effects in pediatric critically ill patients remains unknown.
Neonatal Intensive Care Unit, Department of Pediatrics, University of Messina, Messina, Italy.
Lucia
L
Marseglia
Salvatore
S
Aversa
Ignazio
I
Barberi
Carmelo D
CD
Salpietro
Erika
E
Cusumano
Antonio
A
Speciale
Antonella
A
Saija
Carmelo
C
Romeo
Giuseppe
G
Trimarchi
Russel J
RJ
Reiter
Eloisa
E
Gitto
D002675:Child, Preschool; D002940:Circadian Rhythm / Q000528:radiation effects*; D016638:Critical Illness; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008550:Melatonin / Q000097:blood*; D010865:Pilot Projects; D011446:Prospective Studies; D013997:Time Factors
D008550:Melatonin