Objective: To record, with a thermal camera, peripheral temperature changes during different sedation protocols and to relate the results to changes in the rectal temperature.
Study design: Randomized crossover part-blinded experimental study.
Animals: Eight healthy purpose-bred neutered Beagles (two females and six males) weight 14.5 ± 1.6 kg (mean ± SD) and aged 3-4 years.
Methods: Each dog was sedated four times. Treatments were medetomidine 20 μg kg(-1) and butorphanol 0.1 mg kg(-1) (MB) with or without MK-467 500 μg kg(-1) (MK). Both drug combinations were administered IV and IM as separate treatments. A thermal camera (T425, FLIR) with a resolution of 320 by 240 was used for imaging. The dogs were placed in lateral recumbency on an insulated mattress. Digital (DFT) and metatarsal footpad temperatures (MFT) were measured with thermography. Thermograms and rectal temperature (RT) were taken before and at 3, 10, 20, 30, 45 and 60 minutes after treatment.
Results: At 60 minutes after drug administration, MFT was higher (p < 0.001) after MB+MK (34.5 ± 1.1 IV, 34.8 ± 0.5 IM) than MB (31.1 ± 2.9 IV, 30.5 ± 3.6 IM), DFT was higher (p < 0.001) after MB+MK (33.6 ± 1.4 IV, 34.0 ± 0.6 IM) than MB (26.7 ± 1.4 IV, 26.7 ± 2.5 IM), and RT was lower (p < 0.001) after MB+MK (36.7 ± 0.8 IV, 36.9 ± 0.3 IM) than MB (37.5 ± 0.3 IV, 37.4 ± 0.4 IM), with both routes. The change from baseline was greater with MB+MK than MB in all variables.
Conclusions: Superficial temperature changes can be seen and detected with thermography. MK-467 used with MB resulted in increased superficial temperatures and a decline in rectal temperature compared to MB alone.
Clinical relevance: The sedation protocol may influence core temperature loss, and may also have an effect on thermographic images.
© 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.