Frequency analysis of air and skin temperature in neonates in servo-controlled incubators.

Objective: To test a new system designed for digital recording of skin and air temperature, thereby allowing analysis of cyclic changes in temperature in neonates in servo-controlled incubators.

Methods: Analysis of cyclic changes of serial skin and air temperature in asymptomatic infants in servo-controlled incubators adjusting heat output to the patient's temperature.

Results: In nine asymptomatic neonates ranging from 25 to 40 weeks of gestational age, analysis showed peaks of coherence (squared correlation) between skin and air temperature measurements at periods ranging between 1.5 and 3 h.

Conclusion: We have established a new system to study cyclic changes in skin and air temperature in neonates in servo-controlled incubators. The analysis of this pilot study suggests that the most important changes in skin and air temperature in asymptomatic neonates occur at a periodicity of 1.5 to 3 h, which is similar to that previously described for neonatal temperature. Additional data are required to determine whether this new system may be useful in neonatal care.