[Axillary versus rectal temperature measurement in premature and newborn infants]

We performed a prospective study to see whether axillary temperature accurately reflects rectal temperature in premature and sick mature newborns nursed in incubators and whether axillary temperature measurement is better tolerated than rectal measurement. 561 pairs of rectal and axillary temperatures were obtained in 20 infants. Mean axillary temperatures were 0.16 degree C (SD 0.33 degree C) lower than rectal temperatures. In infants < 1000 g axillary temperatures were only 0.06 degree C (SD 0.30 degree C) lower than rectal temperatures whereas in infants > 2500 g axillary temperatures were 0.37 degree C (SD 0.38 degree C) lower than rectal temperatures. Our results show that axillary and rectal temperatures are interchangeable in extremely premature infants. In newborn infants however 0.4 degree C should be added to axillary temperatures to make them comparable to rectal temperatures. Assessment of infant behaviour during temperature measurement by the nursing staff showed that infants tolerated rectal better than axillary temperature measurements. The decision which kind of measurement will be performed can be taken individually for every infant.