RTA cat and hypothermia
We were presented with an RTA cat this evening, the cat was found lying in a alley and the person who brought the cat in didn't know how long it had been there for.
Symptoms as follows:-
Unconscious, hypovolemic, white mm's, tachycardia, dyspnoea, haemorrhaging from both ears, horizontal nystagmus to the left eye and fixed dilated pupil to the right eye, mandibular symphyseal separation with # ramus and severe hypothermia (no reading on the thermometer). No peripheral or femoral pulses detected. Paddling of the right forelimb and no sensation or deep pain response to the hind limbs/ tail.
Initial tx was 02, warm Gelofusin, solu-medrone IV, antib's, frusemide was administered (no Mannitol in stock) to try to reduce any fluid accumulation within the cranium.
Rads showed no evidence of pneumothorax, diaphragmatic rupture. Chest clear and bladder intact. No obvious # apart from the mandibular ramus.
Over the space of 1 hour and a half the cat showed signs of regaining consciousness and the nystagmus slowed. Weak pulses and sensation returned to the hind limbs. The problem we had was correcting the hypothermia. External warm sources were applied (hotties and hot hands) but the thermometer reading still showed naff all. The cat was wrapped in blankets and bubble wrap and warm fluids were still being administered.
My question is should we have done more to bring the temperature up? Warm water bath or enema? I was concerned about causing vasodilation and creating more of a disturbance to the core temperature. What would everyone else have done? Is it possible for the hypothalamus to have been damaged that badly to result in non- regulation of the temperature? If so would it manifest in hypothermia?
The cat was later transferred to our OOH covering practice and so the outcome is not yet known.
All answers welcome
Thanks Kerry
Hi interesting case i hate these as never know how aggressivley to warm them but few thoughts i had were did you monitor blood pressure from the outset and if you did when the cat showed clinical improvement was the BP normal ? Temperature can be affected by so many things but hypo-perfusion is one of the main times we see a low core body temperature , if a patients MAP is low with a head trauma think this can cause problems as Cerebral perfusion pressures are dictated by MAP and Intra-cranial pressure
also how did you warm the fluids administered was it given through a fluid warmer or warm baggies around the fluid bag ?
we are lucky in that we have 2 paediatric incubators we can use for these cases and increase the environmental temp as well as providing hot baggies and hot hands , although i am not convinced how successful hot hands would be at increasing core temperature and may just be causing peripheral vasodilation
there is also the possibility that the cat dropped the temperature as a neouroprotective measure , it is well documented and carried out in humans tha often with head traumas doctors may induce a clinically controlled hypothermia and i guess we have to wonder if a cat may do the same as a protective mechanism ?
not very helpful but sure you did all you could
Hi Kath, thanks for replying,
Unfortunately we don't have any means of measuring BP (very small and under-equipped practice!) The fluids were warmed prior to IV administration and also the giving set was placed in a bowl of warm water to keep the temperature elevated. The cat's temperature didn't budge. We used hot hands and a hottie bottle to warm the core temperature along with bubble wrap and blankets, also had a hair dryer on him at one point as he was soaking wet form lying in the rain for goodness knows how long. I'm sure that would have caused some degree of vasodilation but I think the evaporation of body heat needed to be stopped. I just arrived home that evening wondering if I could have done anything else to help? Sadly he crashed upon arrival to the emergency OOH clinic. :'(
Just a couple of things to add really as it sounds like you were doing most of the things you could be doing.
I agree with Kath that bp monitoring is the one thing that would be really helpful in this sort of case. Without bp measurement then careful monitoring of the heart rate for evidence of reflex hypertension causing bradycardia (Cushing reflex) is essential.
If you were not doing so already then elevating the cats head at an angle of 15-30 degrees whilst taking care not to compress the jugulars (by kinking the neck) is recommended. X-ray positioning wedges can be helpful here. For similar reasons avoiding anything that might cause swelling of the neck or jugular distension - aggressive jugular venupuncture for example - is beneficial.
Did you coma score this cat? Again it's another easy to use tool that you could implement in future cases that will help to monitor for changes and assess the effectiveness of your therapy.
Did you monitor blood glucose? In humans persistent hyperglycaemia has been shown to be a poor prognostic indicator in head trauma cases. Evidence is lacking in cats, but I believe that there have been a couple of small studies suggesting that persistent hyperglycaemia is a an indicator of more severe brain injury (which might suggest reduced survival). Similarly hypoglycaemia is bad, and if the glucose is falling below 3.0mmol/l I would be considering supplementation.
One final comment - Corticosteroids are now considered contraindicated in cases of traumatic brain injury as they have been shown to significantly decrease survival rate.
Thanks for that Sam, the article is very interesting and I'll pass it on to the other staff to have a look at.
We found out today that sadly the cat didn't survive :(
I think I'd have felt the same and been cautious in regards to administering a warm water enema incase it caused other issues. From the sounds of it to me you did everything possible to try to increase body heat.
I have just found this article in Compendium Vol 23 No6 June 2001 (http://cp.vetlearn.com/Media/PublicationsArticle/PV_23_06_506.pdf ) regarding hypothermia that I found quite interesting.
I'd be interested to hear how this case developed.
Sam