Anaesthetic monitoring

Re: Anaesthetic monitoring

Kate Richardson — Wed, 14 Jul 2010 09:55:45 GMT

[quote user="Kate Richardson"]

Little tip for sc fluids in a conscious cat (sorry if you know this already) but attach a giving set to bag of fluids with a needle on the end, insert said needle under skin (I usually use a 20gauge 1 inch or a 21g 5/8 needle) and let the fluids run in as fast as the set will allow. Cats tolerate this really well, compared to trying to inject fluid. Some cats will sit happily in cage whilst fluid runs in. If you want to give a set amount, burettes are great.

[/quote]

Michael, next time you have a cat needing sc fluids, whether at home or in the clinic, try it this way. Unless the cat is really flat, most object to the fluid being injected as it goes in under a lot more pressure plus the needle moves around more, plus a 50ml syringe is quite unwieldy to handle (esp if you have little hands like me!) and you can give more fluid; ideally at home based on daily maintenance rates. You will be pleasantly surprised

My boss in Australia once hooked up a cat to a 500ml bag of fluid and ran it in via a giving set and then proceeded to forget about the cat! 500mls later and one very jelly feeling cat later, but no illeffects whatsoever! Am not condoning this but it does give show how safe sc fluids can be. And yes, the whole bag went in in one spot!

Some good papers on peri-operative anaesthetic risks in small animals if you find Dave Brodbelt on the RVC website and look on his research http://www.rvc.ac.uk/Staff/dbrodbelt.cfm some links to PubMed there. In cats, 60% of peri-op deaths occurred in the first 3 hours after the ga, highlighting the importance of monitoring during recovery, hypothermia being a big issue.

Re: Anaesthetic monitoring

Martin Atkinson — Wed, 14 Jul 2010 09:45:03 GMT

I heard about skin button a couple of years ago from Kit Sturgess so I'm surprised more people haven't. I think I'll start a new thread on this as it may be of interest to more forum users who have given up following this one as its got a bit out of control.

Re: Anaesthetic monitoring

Laurence Webb — Wed, 14 Jul 2010 09:18:05 GMT

The reseon for using it in my own cat was that he just wouldn't keep still to give fluids, either by syringe or with a needle on a giving set. He'd sit on a lap quite happily but would continually move around and roll on his back. If you tried to keep him stationary he'd get annoyed and try to run off. With the indwelling catheter you could attach the giving set and let it run in whilst he rolled around purring.

The downside was having a catheter tip hanging out of his back. If you could do the same with a button that is flush with the skin that would be a step forward I think.

I'd still go for the simplest route possible though - needle on a giving set would be by first choice.

Re: Anaesthetic monitoring

Michael Woodhouse — Wed, 14 Jul 2010 00:17:08 GMT

Interesting Laurence. I trained a couple of owners to give s/c fluids at home to end stage cats, sometimes makes a real difference, even just 50ml/day.

I dispense 500ml bags of Hartmans, a 50ml syringe (to re-use) and a new 21G 5/8" needle per day. I would only do it for cats that tolerate the injections when I give them, but not sure what extra advantage is given by the button? It's the pressure of large volumes of fluid I find the cats resent, not the piercing of the skin with the needle.

Re: Anaesthetic monitoring

Rob Loxley — Wed, 14 Jul 2010 00:12:32 GMT

[quote user="Laurence Webb"]I've not heard of skin buttons. Where do you get them from?[/quote]

http://milainternational.com/us/products/small-animals/skin-button-sub-q-hydration.html

Direct Medical Supplies are the UK distributor

Personally have found fluids from a bag and giving set by gravity using a 21g needle is well tolerated by cats at home. Most patients at the point of needing regular SC fluids aren't cases I'd be rushing to sedate/GA.

Re: Anaesthetic monitoring

Vikki Halliday LLB — Tue, 13 Jul 2010 23:42:42 GMT

[quote user="Anthony Todd"]Probably because its computer has worked out your reaction time........ [that's a JOKE][/quote]

It's getting sad whe you have to point that out.

I like the tip about S/C fluids, will def try that on next financially constrained cat dental. ( prefer I/V because in my book if you can't have a catheter in, the anaesthetic is possibly more risky).

Re: Anaesthetic monitoring

Laurence Webb — Tue, 13 Jul 2010 21:52:05 GMT

I put an in-dwelling s/c catheter in to my own cat when he had CRF a few years ago and it simplified the fluid administration a lot but I've not heard of skin buttons. Where do you get them from?

Re: Anaesthetic monitoring

Evelyn Barbour-Hill — Tue, 13 Jul 2010 20:52:41 GMT

[quote user="Martin Atkinson"]S/C fluids are not going to restore circulating fluid volume very rapidly so are pretty useless as a means of maintaining perfusion under anaesthetic, but do have a role to play in more chronic situations with mild dehydration. Is anyone else out there using skin buttons? (For the uninitiated these are little ports, that are literally implanted and 'heal' into the skin, which then facilitates the injection of large volumes of fluid subcutaneously with no need for a hypodermic needle in hospital or at home). I see a great potential for these for treating CKD cases that despite being PD are often under-hydrated which accelerates further renal failure but although I've seen dramatic benefits with them they are not greeted with universal enthusiasm by owners as a minor surgical procedure is required to implant them. Unfortunately the cases I've used them in have been in terminal renal failure and although they helped I feel the more appropriate cases are those with less advanced disease. This may mean they are implanted and in use for many months, I wondered if anyone has long term experience. Is this worth starting a separate thread?[/quote]

Sounds interesting, tell us more.

Re: Anaesthetic monitoring

Glen McIntosh — Tue, 13 Jul 2010 11:30:07 GMT

[quote user="Hannah Wynne Richards"]If a cat is on IV it's an intensive care situation, and either my nurse or I will be checking them very often-10/15 minute gaps at most[/quote]

I use IV fluids in cats routinely and, these days, subcut fluids rarely, most often in cases where cost issues preclude iv fluids, or on an outpatient basis.

The use of iv infusion pumps pretty much removes the risk of fluid overload in cats, provided you are using sensible rates. I would not give a cat iv fluids without an infusion pump if I could possibly avoid it. They make life so much easier in a lot of ways.

Re: Anaesthetic monitoring

Martin Atkinson — Tue, 13 Jul 2010 10:04:13 GMT

[quote user="Bob Russell"]

When I saw practice (a long time ago!) a vet in Edinburgh used to recommend intracat fluids! S/C I/P and occ I/V. They did well then and this has worked well for me for a lot of years.

My nurses are keen for i/v and it irritates them that they do not have much to monitor if I give fluids s/c.

For a dehydrated cat 'intracat' works well. No overload problems unless i/v.

[/quote]

S/C fluids are not going to restore circulating fluid volume very rapidly so are pretty useless as a means of maintaining perfusion under anaesthetic, but do have a role to play in more chronic situations with mild dehydration. Is anyone else out there using skin buttons? (For the uninitiated these are little ports, that are literally implanted and 'heal' into the skin, which then facilitates the injection of large volumes of fluid subcutaneously with no need for a hypodermic needle in hospital or at home). I see a great potential for these for treating CKD cases that despite being PD are often under-hydrated which accelerates further renal failure but although I've seen dramatic benefits with them they are not greeted with universal enthusiasm by owners as a minor surgical procedure is required to implant them. Unfortunately the cases I've used them in have been in terminal renal failure and although they helped I feel the more appropriate cases are those with less advanced disease. This may mean they are implanted and in use for many months, I wondered if anyone has long term experience. Is this worth starting a separate thread?

Re: Anaesthetic monitoring

Hannah Wynne Richards — Tue, 13 Jul 2010 09:53:43 GMT

I often use s/c fluids in cats-because it's difficult to drown them !!!!!!!!!!!!!!!!!!!!!!!!!!!!!

If a cat is on IV it's an intensive care situation, and either my nurse or I will be checking them very often-10/15 minute gaps at most

Wynne

Re: Anaesthetic monitoring

Anthony Todd — Tue, 13 Jul 2010 08:32:00 GMT

[quote user="robloxley"]Well in-circuit vaporisers are in this (2004) graduate's lecture notes - Stephens and Komesaroff machines being mentioned.[/quote]

Yeah, but in a good, bad, neutral, or derogatory context?

Re: Anaesthetic monitoring

Anthony Todd — Tue, 13 Jul 2010 08:28:55 GMT

[quote user="james hunt"]Find the syringe driver a little annoying in that it starts telling you it's empty when there's still about 5ml left of a 20ml syringe but usually performs ok. Usually start around 5-6ml/kg/h during anaesthesia in cats.[/quote]

Probably because its computer has worked out your reaction time........ [that's a JOKE]

Re: Anaesthetic monitoring

Rob Loxley — Mon, 12 Jul 2010 23:13:53 GMT

[quote user="Anthony Todd"]Absolutely right but this is not taught to VNs and is not accepted by most newer graduates who blow the cuff up with "up to 3mls of air" in a cat!![/quote]

Again as a recent-ish graduate, inflating the cuff just until no leak was audible was what we were taught. As for the what VNs are taught, when was that ever the yardstick? And nobody did take me up on the discussion of eye position.

Re: Anaesthetic monitoring

Anthony Todd — Mon, 12 Jul 2010 22:49:25 GMT

[quote user="Kate Richardson"][quote user="Martin Atkinson"] Blow up the cuff and listen as the rebreathing bag is expressed until there is just no air escaping.[/quote][/quote]

Absolutely right but this is not taught to VNs and is not accepted by most newer graduates who blow the cuff up with "up to 3mls of air" in a cat!!

The method in the dog produces a rather rude noise, satisfying and technically correct when it just stops........

Re: Anaesthetic monitoring

Rob Loxley — Mon, 12 Jul 2010 22:46:22 GMT

[quote user="Evelyn Barbour-Hill"]I might be wrong but my impression is that in-circle vaporiser systems are never mentioned in vet school, or if they are it is in derogatory terms. I know there are some students on this forum: come on , tell us if I am right.[/quote]

Well in-circuit vaporisers are in this (2004) graduate's lecture notes - Stephens and Komesaroff machines being mentioned.

Re: Anaesthetic monitoring

Evelyn Barbour-Hill — Mon, 12 Jul 2010 20:10:23 GMT

[quote user="Anthony Todd"]I can't see the disadvantage of a cuff, correctly inflated, ie to give a seal at normal respiratory pressures, and, for sure, if you need to bag it you won't get leakage and you know where the gas is going.[/quote]

I agree. On the other hand, if you don't have a cuff you can use a larger tube with a larger lumen. I use both (not at the same time of course)

Tthe cuff is not there to prevent fluids going down however.. You should have a throat pack for that.

[quote user="Anthony Todd"] do wonder why the Stephens is now regarded as prehistoric and/or unsafe. Notice how all the old duffers like myself seem to like them...... but have been too scared to admit until now![/quote]

I might be wrong but my impression is that in-circle vaporiser systems are never mentioned in vet school, or if they are it is in derogatory terms. I know there are some students on this forum: come on , tell us if I am right.

Re: Anaesthetic monitoring

Kate Richardson — Mon, 12 Jul 2010 20:07:22 GMT

[quote user="Martin Atkinson"] Blow up the cuff and listen as the rebreathing bag is expressed until there is just no air escaping.[/quote]

Thats exactly what they said at the cpd I went to recently and use a 2ml syringe so minimise danger of over inflating. Cuffs not necessarily a problem unless over inflated, movement is a bigger problem, so agree totally- disconnect animal when turning patient.

Re: Anaesthetic monitoring

Kate Richardson — Mon, 12 Jul 2010 19:42:21 GMT

Unless you have someone capable of monitoring iv fluids correctly I would agree that sc is safer, or small boluses iv intermittently.

IV rates I use 5mls/kg/hour when under ga (for cats) and rarely go above this.

Someone commented on nurses getting irritated when fluids are given sc rather than giving it iv- sorry to offend any nurses, but tough sh1t! If you are more comfortable with sc fluids then it is your decision, maybe point out to them the peri-op stats related to iv fluids. I usually use iv fluids in older cats as a routine and would rather spend the owners money on this than pre-op bloods in a cat that appears clinically well if money is tight, and definitely use fluids if they have renal insufficiency.

Re: Anaesthetic monitoring

Martin Atkinson — Mon, 12 Jul 2010 19:32:16 GMT

Never had a problem with overperfusing cats or with cuff induced tracheal necrosis and I use standard giving sets and cuff all my tubes! Effective monitoring and working out correct fluid requirement and rates is all that's required and a rough measurement of CVP by bag height above patient (arghh..I here the pedants say)! Blow up the cuff and listen as the rebreathing bag is expressed until there is just no air escaping. I wouldn't perform any anaesthetic without a cuffed tube, IMO there's far more likleyhood of inhaling vomit (or fluids during a dental prophylaxis) than there is from tracheal damage due to the cuff. Once had a tracheal rupture from the tip of the tube due to a nurse constantly turning a cat during a dental - lesson learned: always disconnect when turning.

Re: Anaesthetic monitoring

james hunt — Mon, 12 Jul 2010 18:50:51 GMT

Yes i tend to use 4.5-5mm uncuffed ET tubes.

Find the syringe driver a little annoying in that it starts telling you it's empty when there's still about 5ml left of a 20ml syringe but usually performs ok. Usually start around 5-6ml/kg/h during anaesthesia in cats. Increase if blood pressure low. Back off if blood pressure normal.

Re: Anaesthetic monitoring

Michael Woodhouse — Mon, 12 Jul 2010 18:39:44 GMT

[quote user="Bob Russell"]

When I saw practice (a long time ago!) a vet in Edinburgh used to recommend intracat fluids! S/C I/P and occ I/V. They did well then and this has worked well for me for a lot of years.

My nurses are keen for i/v and it irritates them that they do not have much to monitor if I give fluids s/c.

For a dehydrated cat 'intracat' works well. No overload problems unless i/v.

[/quote]

I almost never put a cat on a drip, unless really really flat. I use mainly sub cut and have never had a problem. Warmed fluid s/c seems to disappear quickly even in very clinically dehydrated cats. We don't have drip pumps and the buggers twist the sets up and remove them.

Re: Anaesthetic monitoring

Anthony Todd — Mon, 12 Jul 2010 18:37:42 GMT

[quote user="james hunt"]I wouldn't use a cuffed tube in a cat[/quote]

I can't see the disadvantage of a cuff, correctly inflated, ie to give a seal at normal respiratory pressures, and, for sure, if you need to bag it you won't get leakage and you know where the gas is going.

Humans are paranoid about cuff pressure and have a sort of meter which is standard I think, fitted to the cuff tube..

[There is a major operation described where part of the gut is used to replace the necrotic trachea from tracheal necrosis in prolonged neonatal surgery....]

Often vets use cuffs two or more sizes too small, eg a 3 or 3.5 in a big cat and a cuff will be needed in these cases I reckon.

[quote user="james hunt"]Newer out of circuit calibrated vapourisers seem to have pretty accurate output down to about 500ml/min.[/quote]

I do wonder why the Stephens is now regarded as prehistoric and/or unsafe. Notice how all the old duffers like myself seem to like them...... but have been too scared to admit until now!

[quote user="james hunt"]or use syringe driver now.[/quote]

How do you find their use in practice ie blocks and blowoffs etc and what is you rule of thumb for infusion rates??

Re: Anaesthetic monitoring

Bob Russell — Mon, 12 Jul 2010 16:09:12 GMT

When I saw practice (a long time ago!) a vet in Edinburgh used to recommend intracat fluids! S/C I/P and occ I/V. They did well then and this has worked well for me for a lot of years.

My nurses are keen for i/v and it irritates them that they do not have much to monitor if I give fluids s/c.

For a dehydrated cat 'intracat' works well. No overload problems unless i/v.

Re: Anaesthetic monitoring

james hunt — Mon, 12 Jul 2010 15:54:42 GMT

[quote user="Clive Ansell"]As there is a real risk of over purfusion with iv fluids in cats, is there any reason that supportive fluids cannot be given subcut[/quote]

I suppose administering sc isn't going to support blood pressure acutely in the vasodilated circulation under GA, but may well do less harm than overperfusing...