Effect of an Insulation Device in Preventing Hypothermia during Magnetic Resonance Imaging Examinations for Dogs and Cats under General Anesthesia

Abstract

Dogs and cats under general anesthesia may develop hypothermia. When performing a magnetic resonance imaging (MRI) examination, it is not possible to place a magnetic material in the MRI room, and MRI equipment requires a low room temperature. This study investigated the effectiveness of a heat insulating device that prevented hypothermia during MRI examinations in dogs and cats. The animals that underwent MRI examinations under general anesthesia were divided into control groups (no covering) and heat insulating groups (wearing bubble wrap and down cloth blankets), and their body temperatures were measured before and after the MRI examinations. The changes in body temperatures were as follows: control dogs (n = 17), median of −1.0 (from −2.5 to 0.3) °C; heat insulated dogs (n = 7), −0.3 (from −0.8 to 0.2) °C; control cats (n = 14), −1.85 (from −2.7 to −0.6) °C; and heat insulated cats (n = 12), −0.8 (from −1.5 to −0.1) °C. These results revealed that the bubble wrap and down cloth blanket significantly prevented hypothermia and heat loss from the body surface during MRI examinations of dogs and cats.

Variation of rectal temperature in dogs undergoing 3T-MRI in general anesthesia

“…In our study sample animals with medium to long fur experienced less heat loss, a finding that might be considered analogous to the use of insulation materials, as proposed by Özer et al ( 21 ). This observation may seem intuitive, yet it can become a critical factor when performing MRI scans on large dogs with medium or long fur.…”

“…Additionally, the explicit selection of dogs with a body mass below 10 kg in this study may contribute to different outcomes. However, another study ( 21 ) that examined a population of larger dogs found sporadic cases where dogs either maintained their body temperature or exhibited a slightly higher temperature (+0.3°C) after the MRI. The use of heat insulation led to a higher mean body temperature after the MRI but did not alter the number of dogs with a positive temperature difference.…”

“…Continuous monitoring of body temperature within the MRI scanner is challenging and expensive since most temperature monitoring systems are unsuitable for use within the magnetic field ( 2 ). Therefore, measuring temperature before and after the MRI scan is an accepted surrogate method to assess temperature changes during the procedure ( 2 , 7 , 12 , 13 , 20 , 21 ). Implementing MRI-compatible temperature monitoring devices would only be justified if significant temperature variations occur regularly.…”

Effects of peripheral active warming and passive insulation on core body temperature during feline ovariohysterectomy: a multi-arm randomized clinical trial

“…A better insulating material might enhance the active warming device’s performance, such as a study that used bubble wrap and a down cloth blanket to insulate patients warmed by a hot water bottle. 26 The heating element is visible in the active group’s thermal image (see Figure 1 ), indicating poor insulation. While better materials might improve the performance of passive insulation, superior warming has consistently been observed with a well-insulated heat source as compared with high-quality insulation alone.…”

“…While better materials might improve the performance of passive insulation, superior warming has consistently been observed with a well-insulated heat source as compared with high-quality insulation alone. 24 , 26 Third, drugs used in anesthetic protocols have different effects on vasoconstriction and may be associated with different responses to heat loss prevention, particularly during phase 1 hypothermia. Specifically, acepromazine, thiopentone sodium and halothane promoted vasodilation in dogs treated with warm water mattresses applied to their extremities, potentially increasing heat transfer to the extremities.…”