Basic colloid question!

Re: Basic colloid question!

Glen McIntosh — Wed, 08 Sep 2010 00:27:14 GMT

With HGE you would expect to see haemoconcentration in the form of a very high PCV and, at least in my experience, TP will usually be within normal limits, (perhaps high normal in some cases) at least initially. The main thing I am trying to acheive with treatment, at least initially, is heamodilution so as to improve perfusion as these cases tend to present with poor perfusion which manifests itself as high heart rate and poor peripheral pulses. I tend to treat these guys with crystalloids, usually hartmans, in the first instance, using one or more boluses of 20 ml/kg over 30 mins or so until I reach the desired end point of normalised heart rate and improved peripheral pulses, then twice maintenance rates until the dog is recovered and eating.

I would probably avoid colloids as the primary resuscitation fluid in these cases, since, as previous posters have mentioned, there may be a degree of dehydration associated with HGE that will not be resolved with colloids alone.

I will perform repeat PCV/TP measurements around 2 and 6 hours after start of treatment to satisfy myself that the PCV is normalising, but also to monitor TP, which will often become subnormal in these cases. When TP is approaching or becomes subnormal then I will often add a colloid bolus, followed, perhaps, by a cri in some cases, as a way of providing oncotic support to these patients. Usually the TP or albumin levels do not reach critically low levels such that peripheral oedema occurs, however it does seem prudent in some of these cases to make sure that doesn't happen, by providing IV colloids.

However, other than when TP becomes or approaches sub normal, crystalloids will be my fluid of choice for HGE treatment.

In your case, which has concurrent heart disease, I would be even more cautious about using colloids given that they are more likely to result in an unintended hypervolaemia that might push the animal into exhibiting symptoms of CHF (and I would also be less aggressive with my initial crystalloid resuscitation). But I would still consider using them cautiously in this type of case if TP became subnormal after cystalloid resuscitation.

I don't know if for sure you can supplement K in a colloid, since I will always have a crystalloids running in as well and would supplement them. But I can see no reason why not if you had to, since colloids are compatible with crystalloid solutions like normal saline and hartmans, and KCl is simply another type of crystalloid solution.

Re: Basic colloid question!

emma o'connor — Tue, 07 Sep 2010 19:33:28 GMT

I would agree with Mark as well. As far as my understanding goes, Colloids are good at maintaining volume and supporting pressure but do little to help correct any underlying dehydration, which i would expect is the case in a dog with HGE. We would tend to give crystalloids concurrently via a second iv line, but be careful with the infusion rate and monitor heart rate and respiratory rates and adjust accordingly.

There was a good free online cpd course not too long ago by Dechra (i think it was them) on fluid therapy in small animals which i found to be very useful, it may still be available.

Good luck

Re: Basic colloid question!

Martin Jones — Tue, 07 Sep 2010 17:21:08 GMT

With Mark on that one (clearly, there's a group of us 'idiots'), with the observation that as the patient's likely to be both acidotic and dehydrated, its true potassium deficit may be more pronounced still. You mightn't be able to push all the potassium you want intravenously, so some good old-fashioned enteral support might be in order.

Re: Basic colloid question!

Mark Holmes — Tue, 07 Sep 2010 14:51:38 GMT

As far as I am aware you are supposed to supplement colloids with crystaloids anyway. Colloids are a good volume replacer for the vascualr system, and support blood pressure but do little for the interstitial space as they are held intravascularly. Therefore a cystalloid is required as well. However I would be very careful about over doing fluids if heart dz is a problem.

Sorry if I am teaching you to suck eggs. (Equally sorry if I am wrong)

Mark