Servocontrolled Radiant Warmers and the Role of Thermistor Probe Reflective Shields in Neonates

Servocontrolled radiant warmers are widely used for infants' temperature maintenance. Covering the attached skin temperature (or thermistor) probe with a reflective shield may prevent inadvertent warming of the probe by the radiant heat source. However the shield itself might cause falsely elevated or lowered measured skin temperatures, and the use of such shields, while widespread, is not universal nor standard of care. This study aims to document the effects of a reflective shield on the measured skin temperatures of neonates nursed under radiant warmers.

Stable newborn infants in the Maimonides NICU who are being nursed under a radiant warmer will be studied. As part of routine care, the thermistor probe will be applied and the desired servocontrolled skin temperature set. Once stabilized, a trimmed reflective shield to cover only the probe itself will be placed over the thermistor probe. Changes in measured skin temperature and warmer power output will be recorded non-invasively, as well as the time taken to reestablish baseline status. A full-sized reflective shield will then be placed over the thermistor probe and the same observations recorded, then repeated 15 minutes later. At the time of a subsequent routine change in thermistor position, the same procedure will be followed, but omitting the intermediate step of using the smaller trimmed shield. Continuous core temperatures will be monitored via a short rectal probe during the study periods.

The effect of the use of the different size temperature probes will be examined by analyzing the effect on measured skin temperature.