Related Experiment Videos
The effect of sleep state on active thermoregulation in the premature infant
Insights
Premature infants maintain active thermoregulation during Rapid Eye Movement (REM) sleep, unlike adults. This study shows their oxygen consumption increases during mild cold stress, even in REM sleep, indicating intact thermal control.
Area of Science:
- Neonatal physiology
- Sleep science
- Thermoregulation
Background:
- Sleep state alterations can affect thermoregulatory mechanisms in premature infants, impacting homeostasis.
- Adults may suspend homeothermic regulation during REM sleep, a phenomenon not yet fully understood in neonates.
Purpose of the Study:
- To investigate thermoregulatory responses in premature infants during REM sleep.
- To determine if premature infants exhibit intact thermoregulatory mechanisms during REM sleep under mild thermal stress.
Main Methods:
- Measured oxygen consumption (VO2), carbon dioxide production (VCO2), heart rate, and transcutaneous oxygen pressure (TcPO2) in six premature infants (33-35 wk gestation).
- Infants were studied under radiant warmers with controlled mild thermal stress (skin temperature allowed to fall).
- Sleep state was objectively scored using electroencephalogram (EEG), electrooculogram (EOG), electromyogram (EMG), and behavioral criteria.
Main Results:
- Oxygen consumption (VO2) significantly increased during cool periods across all sleep states, including REM sleep.
- Mean VO2 increases during cooling were 21.5% (Awake), 23.3% (Indeterminate), 11.1% (REM), and 5.3% (NREM).
- No significant difference in VO2 was observed between REM and NREM sleep at thermoneutrality.
Conclusions:
- Premature infants demonstrate active thermoregulation during REM sleep, contrasting with adult responses.
- Thermoregulatory responses in premature infants remain functional even during REM sleep under mild thermal challenges.
Abstract:
Alterations in thermoregulatory mechanisms related to sleep state may play an important role in the problems of homeostasis experienced by the premature infant. In the adult, homeothermic regulation of body temperature may be suspended during REM. We measured oxygen consumption (VO2) in six premature infants 33-35 wk gestation both at thermoneutrality and during a mild thermal stress to determine whether thermoregulatory responses were intact during REM sleep. All infants were studied under radiant warmers. Skin temperature was allowed to fall 7-8 times during a 6-8 h study period while VO2, VCO2, heart rate and TcPO2 were continuously recorded. Sleep state was scored using EEG, EOG, EMG and behavioral criteria. A total of 1,162 one-min epochs were scored. In all states including REM, VO2 was significantly higher during the cool periods. The mean increases: 21.5%, 23.3%, 11.1% and 5.3% for Awake, Indeterminate, REM and NREM respectively. When REM and NREM were compared at thermoneutrality, there was no difference in the VO2 (8.80 +/- 0.11 and 8.93 +/- 0.15 cc/kg/min, mean +/- S.E., for REM and NREM, respectively). We conclude that in contrast to the adult, active thermoregulation occurs in the premature infant during REM sleep.