Comparison of infrared thermography-derived body surface temperature in awake and inhalation-anesthetized Wistar albino rats: A paired study

Abstract

Infrared thermography (IRT) is increasingly used in laboratory animal research because it enables contact-free assessment of body surface temperature. However, inhalation anesthesia may alter thermoregulation, peripheral perfusion and measurement stability, potentially complicating the interpretation of thermographic endpoints. This paired study evaluated the association between inhalation anesthesia and IRT-derived body surface temperature in Wistar albino rats. Twenty rats (10 females and 10 males) were evaluated under awake and inhalation-anesthetized conditions. The mean line-ROI thermographic surface temperature was 29.33 ± 1.09 °C in the awake condition and 31.24 ± 1.49 °C during inhalation anesthesia. The mean paired difference was 1.91 °C (95% CI: 0.94 to 2.89 °C; paired t = 4.12, p < 0.001; Cohen's dz = 0.92). A Wilcoxon signed-rank sensitivity analysis also demonstrated a statistically significant difference between conditions (p < 0.001), confirming the consistency of the finding across parametric and non-parametric analyses. Inhalation anesthesia resulted in a significant increase in IRT-derived thermographic surface temperature compared with the awake condition. Therefore, anesthesia status, ROI definition, camera settings and technical replicate handling should be reported and standardized when IRT is used as an outcome measure in laboratory animal studies.