Axillary temperature measurement is not better tolerated than rectal in premature infants. Influence of axillary and rectal temperature measurement on heart rate, oxygen saturation and cerebral haemodynamics and oxygenation

Background: Aim of this study was to assess, by use of monitoring parameter s and near infrared spectroscopy (NIRS), whether premature infants tolerate axillary temperature measurement better than rectal. Methods: Twenty-one infants were studied. Birth weight was 540-1680 g (medi an 840 g), weight at the time of investigation 470-1500 g (Median 920 g), g estational age 24-31 weeks (median 29 weeks), age at time of investigation 4-25 days (median 11 days). Four pairs of axillary/rectal temperatures were taken in every infant. Heart rate and oxygen saturation were monitored. Us ing NIRS cerebral oxygenated and deoxygenated hemoglobin were measured and total cerebral hemoglobin and the cerebral oxygenation index were calculate d. Results: Mean heart rate increased slightly but significantly from baseline during axillary and rectal temperature measurement (axillary: +6/min (+/-7 ): p < 0.0001; rectal: +4/min (+/-6); p < 0.0001). Peak increase in heart r ate was significantly higher during axillary than during rectal temperature measurement (axillary: + 18/min (+/-10); rectal: +14/min (+/-8); axillary versus rectal: p = 0.02). There was no difference in the number of measurem ents during which oxygen saturation dropped intermittently below 88% (recta l: 27 % of measurements; axillary: 20% of measurements). NIRS parameters we re not significantly different between axillary and rectal measurements: ce rebral oxygenated hemoglobin and the oxygenation index showed a decrease in cerebral oxygenation during both, axillary and rectal measurement. Conclusions: Axillary temperature measurement is not better tolerated than rectal in premature infants.