Melatonin status in pediatric intensive care patients with sepsis.

OBJECTIVE: Considering the potential immunomodulatory role of melatonin and its direct antioxidant activity, disturbances of the melatonin secretion pattern in the septic conditions could be particularly unfavorable. The aim of this study was to evaluate the nocturnal melatonin concentration and total 24-hr excretion of 6-sulfatoxymelatoninsulfate, melatonin's major urinary metabolite, in children with sepsis in the pediatric intensive care unit.

DESIGN: Prospective observational pilot study.

SETTING: A pediatric intensive care unit.

PATIENTS: Twenty septic and 20 nonseptic children admitted between February 2008 and January 2010.

INTERVENTIONS: None.

MEASUREMENT AND MAIN RESULTS: Blood and urine samples were obtained from each patient on days 1, 2, 3, 5, and 10. There were no significant differences between the groups concerning age and gender. The median nocturnal melatonin concentrations were not significantly different between septic and nonseptic patients during the study period (p > .05). A subgroup analysis in septic patients showed that the nocturnal melatonin concentrations in nonsurvivors were significantly higher than in survivors, whereas total 6-sulfatoxymelatoninsulfate excretions in nonsurvivors were significantly lower than in survivors (p = .001 and p = .015, respectively). Furthermore, nocturnal melatonin concentrations of septic patients in septic shock state were statistically significantly higher than those of septic patients without septic shock state (p = .002). The 24-hr 6-sulfatoxymelatoninsulfate excretions in septic patients with liver dysfunction were found significantly lower than those in septic patients without liver dysfunction (p = .015). The presence of sedation and mechanical ventilation had no effect on the nocturnal melatonin concentrations in septic patients (p = .953 and p = .922, respectively).

CONCLUSION: The present study shows that, in contradiction to results in adult patients, the nocturnal melatonin concentrations are not decreased in septic pediatric intensive care unit patients despite severe disease. Further investigations are needed to identify whether treatment with melatonin may have beneficial effects in pediatric intensive care unit patients with sepsis/septic shock.