N1033787
• Severe hypothermia( 33 – 35.5 ° C)
• and Critical(< 33 ° C)( Oncken, Kirby and Rudloff, 2001)
1.2 MRI Imaging
Magnetic resonance imaging( MRI) is necessary in many neurological patients to investigate diseases and gain a diagnosis. It is known that maintaining normothermia in anaesthetised animals undergoing MRI investigations is difficult due to the nature of the scanner. In dogs anaesthetised for thoracolumbar hemilaminectomy surgery, Bruniges and Rioja( 2019) found that if an MRI was performed in the same GA, the patient had double the risk of developing hypothermia to those that did not. There were several limitations and variable factors to this study however, including different anaesthetists and anaesthetic protocols used, which could have all influenced the results and the occurrence of hypothermia.
The MRI suite must remain at a low temperature to keep the magnet cool and any electrical devices in the room must be nonmagnetic and electrically nonconductive( Khenissi et al, 2017). Suitable warming techniques are therefore limited, as active warming techniques such as forced air blankets or electrical heat pads are unable to be used and would be limited to the use of microwaveable heat pads or hot water bottles. Active surface warming( applying heat to the surface of the animal) has been shown to be beneficial for patients with moderate to critical hypothermia, however, must be used with care to avoid burns, as patients are unable to move away from the heat source and vasoconstricted skin cannot appropriately diffuse direct heat( Brodeur et al, 2017). Passive devices such as wrapping the animal in bubble wrap and down cloth blanket have been shown to minimize a decrease in body temperature, however there were several limitations to this study by Onozawa et al( 2021). The study consisted of a relatively small sample size( 24 dogs and 26 cats) and included mostly small-breed dogs, and so further investigations into the effects of body size in more detail was recommended by the authors. The study also mentions that a hot water bottle was used in both the control, and heat insulation groups, so it is unknown whether the use of bubble wrap and down cloth blanket was beneficial on their own. It could also be difficult to replicate the insulation devices the study uses.
ANIM32126 – EBVN Project 10