Comparing Axillary and Rectal Temperature Measurements in Very Preterm Infants: A Prospective Observational Study

Abstract

<b><i>Purpose:</i></b> The agreement between axillary temperature (AT) and rectal temperature (RT) measurements has not been well established in preterm infants. Therefore, our study aimed to evaluate the agreement between AT and RT measurements in very preterm infants. <b><i>Methods:</i></b> Preterm infants <32 weeks of gestational age were prospectively included. The infants’ body temperature (BT) was measured twice a day from day 1 to day 6. A paired <i>t</i>-test and the Bland-Altman method were used to analyze the difference between the AT and RT. A linear regression model was used to explore the effects of environmental factors on the differences of BT between the axillary and rectal measurements and to calibrate the RT according to the AT. <b><i>Results:</i></b> Eighty infants each underwent 6 paired axillary and rectal measurements. The gestational age varied from 22 to 31 weeks (mean 28 weeks). The birth weight varied from 302 to 1,770 g (mean 1,025 g). The AT was significantly lower than the RT. The difference between the RT and AT significantly increased with increasing RT. The AT and RT demonstrated poor agreement overall; however, the RT can be estimated using the AT with the following equation: RT = −4.033 + 1.116 × AT. Environmental factors, including the incubator temperature, incubator humidity, phototherapy, and application of invasive mechanical ventilation did not affect the differences between the AT and RT measurements. <b><i>Conclusion:</i></b> AT measurements cannot be interchangeably used with RT measurements in very preterm infants.

Association of Moderate Hypothermia at Admission with Short-Term and Long-Term Outcomes in Extremely Low Birth Weight Infants

“…Lastly, axillary temperature measured at ad mission may be lower than rectal temperature, and thus may not fully represent core body temperature 23) . The main strength of this study is that it is the first in Korea to assess long-term neurodevelopmental outcomes associated with admission temperature.…”

Video-Based Elevated Skin Temperature Detection

“…Infrared sensors detect the amount of light energy radiated by an object and determine the temperature of the object using thermodynamic and signal processing techniques [45]- [48]. The approaches advanced by Cho et al and Kocoglu et al measure the temperature of the tympanic membrane (inner ear) that can be utilized as a surrogate for the core body temperature [49], [50]. The developed approaches require frequent sensor adjustment to fit the shape of the ear canal.…”

“…where W obj is the energy emitted by the body, W ref l is the energy emitted by the surroundings, reflected by the object and W atm is the energy emitted by the atmosphere. Using the [45] 1997 ✓ ✓ Valle et al [9] 1999 ✓ ✓ ✓ Craig et al [8] 2000 ✓ ✓ Craig et al [10] 2002 ✓ ✓ ✓ Kocoglu et al [50] 2002 ✓ ✓ Pusnik et al [47] 2004 ✓ Ng et al [51] 2005 ✓ ✓ Sanchez-Marin et al [19] 2009 ✓ ✓ Sagaidachnyi et al [17] 2012 ✓ ✓ Apa et al [74] 2013 ✓ ✓ ✓ Sagaidachnyi et al [18] 2014 ✓ ✓ Jeong et al [43] 2014 ✓ ✓ Tay et al [75] 2015 ✓ ✓ Sharma and Yadav [53] 2017 ✓ ✓ Arieli et al [66] 2017 ✓ ✓ Chaglla et al [52] 2018 ✓ ✓ Rodriguez-Lozano et al [12] 2019 ✓ ✓ Hsiao et al [76] 2020 ✓ ✓ Khan et al [44] 2021 ✓ ✓ ✓ Shajkofci et al [48] 2021 ✓ ✓ Cho et al [49] 2021 ✓ ✓ ✓ Chin et al [55] 2021 ✓ ✓ ✓ Dell'Isola et al [11] 2021 ✓ Khaksari et al [77] 2021 Stefan Boltzmann law, W obj can be written as…”