Transepidermal water loss during sleep in infants at risk for sudden death.

To search for excessive sweating during sleep in infants considered at risk for sudden infant death syndrome (SIDS), we studied 258 infants during one night. There were 134 normal infants (controls), 85 siblings of SIDS victims (siblings), and 39 infants who survived an apparent life-threatening event (ALTE) with no cause found for the incident. Mean postnatal ages were between 10 and 16 weeks. Transepidermal water evaporation rate was measured from the forehead using an evaporimeter during one night's polygraphic sleep recording. Measurements were made before feedings, during the first part of the night, and evaporation rate values were expressed as grams per square meter of body surface area per hour. In the three groups of patients evaporation rates were significantly lower during rapid eye movement (REM) sleep, compared with values measured during quiet wakefulness or nonrapid eye movement (NREM) sleep. Infants with an ALTE had significantly higher evaporation rate values during NREM sleep than the two other groups (20.1 +/- 1.93, 11.3 +/- 0.68, and 11.5 +/- 0.98 for the ALTE, control, and sibling infants, respectively). The differences were not related to age, sex, weight, or rectal temperature. During NREM sleep, evaporation rate values greater than 25 mg/m2/h were seen in 10/190 (5.3%) of the asymptomatic infants and in 11/36 (30.6%) of the infants with an ALTE. The results are in agreement with reports in the literature of repeated night sweating in infants who eventually died of SIDS. Although we are unable to conclude why evaporation rate values are higher in the ALTE group than in the two other groups, we cannot exclude that it reflects differences in autonomous system activity.(ABSTRACT TRUNCATED AT 250 WORDS)