Feline Shock

Re: Feline Shock

jd2008 — Thu, 18 Mar 2010 10:44:53 GMT

ooops. Just re-read my last post and realised it sounded and bit high-handed and "lecture -y"

Didn't mean that at all - just tend to get a bit over-passionate about certain subjects so I hope I haven't caused any offence

Also realised my last comment may have seemed particularly insulting. I certainly didn't mean that you, Rob, didn't know what you were talking about! I was actually thinking about myself - there's a very good chance I'm talking out of my backside.....

Re: Feline Shock

jd2008 — Thu, 18 Mar 2010 09:44:38 GMT

Hi Rob,

Should clarify that I'm not talking about cardiogenic shock or head trauma - more the hypovolaemic/ Very Ill Cat type shock. I always do my best to rule out cardiac disease, head trauma and heamorrhage before deciding my resuscitation approach and I do agree that the approach will always differ subtly depending on the patient.

Yes - we always use infusion pumps and monitor cat intensively until endpoint of resuscitation is acheived . We also always give oxygen. But the unique nature of the shock response in cat (especially the bradycardia and the fact that the bradycardia, hypothermia and hypotension each contribute to a worsening of the other) means they cannot handle large or even moderate amounts of crystalloids as well as dogs/humans. Their cardiac output is so dreadful that you have to be extremely careful with any fluid (colloids included - hence the small boluses and constant monitoring).

The profound hypothermia in these cases will also cause peripheral vasoconstriction to eventually become peripheral vasodilation. This, along with the bradycardia results in more hypotension. Giving large amounts of crystalloids will cause pulmonary oedema - and I do consider 40-50ml/kg/hr a large amount, even if you're constantly monitoring you're taking a risk, I think.

Yes - have seen boluses of colloids cause further bradycardia. I always give it over about 15minutes.

Unless there's a primary cardiac problem I'm not sure dobutamine is of much value.

I'm not an expert by any means and I'm wary of making sweeping generalisations or saying any colleague (especially those at the RVC) is wrong. I know that there isn't any one single "recipe" and there is still some ongoing controversy. I'm just confused and a little concerned that the message isn't getting across to new grads that the "shock" response in cats is very different to that in dogs and the thing that they are taking home (40-50ml/kg/hr) is just too simplistic.

This is where we need somone who actually knows what they're talking about to step in

Jane

Re: Feline Shock

Rob Loxley — Thu, 18 Mar 2010 08:39:04 GMT

[quote user="Jane Dunnett"]Have seen other vets use the 40-50ml/kg/hr crystalloids and watched as the cat developed profound pulmonary oedema.[/quote]

But you're not setting the infusion pump and coming back an hour later? Surely you're constantly monitoring parameters and reassessing as you go

Fluid choice depends on severity of shock, cause/type of shock (e.g. maybe blood or oxyglobin if low PCV following bleed, colloid if low TP in peritonitis/pyothorax, hypertonic saline in head trauma to reduce cerebral oedema, care with speed of admin if ongoing hamorrhage); size of animal (hypertonic saline for a 60kg dog with a GDV is a whole lot less volume to physically get in); concurrent disease (esp cardiac/renal when thinking about fluid overload; pre-exisiting coagulopathy or haemorrhage would make me cautious about colloids) - but isotonic crystalloids would be my usual 1st choice.

How much of the low rectal temperature is due to poor perfusion in shock (rather than true hypothermia) and therefore responds to the fluid therapy? Not suggest warming isn't appropriate.

How about oxygen supplementation too?

Has anyone seen hypotension after bolus colloid tx in cats - heard it can happen?

Anyone using dobutamine?

Re: Feline Shock

Michael Woodhouse — Wed, 17 Mar 2010 22:37:16 GMT

[quote user="Jane Dunnett"]

Have seen other vets use the 40-50ml/kg/hr crystalloids and watched as the cat developed profound pulmonary oedema. I'm assuming they don't get that problem at the RVC?

[/quote]

Never happened when I was in the ICU there!

IF the cat is in profound shock it should be able to handle the fluids. Unless you have fancy drip pumps then I think it is actually quite easy to fluid overload a cat. 4kg cat 50ml/kg/hour in a 20 minute bolus = 66ml = 1 drop per second in a standard giving set..

I'm going to be quiet now because I'm getting out of my depth

Re: Feline Shock

jd2008 — Wed, 17 Mar 2010 22:28:11 GMT

I should also say I've tasked the EMS student with pulling off some of Rebecca Kirby's stuff on feline shock from VIN and waving it under the nose of the ECC guys at the RVC to see if she can get a bit more out of them as to why they favour their particular approach.

I'm really not assuming I'm necessarily right - I'm just a bit baffled now.

Re: Feline Shock

jd2008 — Wed, 17 Mar 2010 22:23:41 GMT

[quote user="Michael Woodhouse"]

If I was going to do bloods I would have done so before fluids.

[/quote]

Quite right. I actually drew the bloods just after I started resuscitating (didn't make that clear in my post)

Have seen other vets use the 40-50ml/kg/hr crystalloids and watched as the cat developed profound pulmonary oedema. I'm assuming they don't get that problem at the RVC?

Re: Feline Shock

Michael Woodhouse — Wed, 17 Mar 2010 22:15:01 GMT

2006 RVC grad here! Was also taught 40-50ml/kg/hour crystalloids. I asked about colloids during the rotation and was told that extrapolating from human medicine patients treated with crystalloid had better survival than those treated with colloids.I'm not interested enough in cats to actually search the literature for myself!

If I was going to do bloods I would have done so before fluids.

I'm really a cow vet (who dabbles with small animals to my annoyance) so I wouldn't dream of commenting further on your treatment!