Calling thiodinovets and ket users

Re: Calling thiodinovets and ket users

mariette asselbergs — Tue, 11 Nov 2014 06:04:37 GMT

My tuppence:

When I just qualified we used thiopental iv in dogs and intraperitoneal in cats (for spays).

Then 10 years later in Dutch SA practice they used a lovely combination of palfium and ACP for bitch spays. Worked a treat and very safe, but I never saw palfium in vet practice again when everybody started to use the inhalation anaesthesia. I used it on my own dog for a caesarean and a later spay. As I remember different breeds had a bit of a different reaction to it, requiring more or less palfium for a good deep sleep.

In Mozambique we used the widely available ketamine/xylazine combination im for ops (spays, casrtrations, enucleations, amputations, stitch ups). It was quite safe but a bit rough on the dogs/cats for waking up. Probably because the ketamine part of the combi was high and they were quite hallucinatory for a while afterwards.

Mariette

Re: Calling thiodinovets and ket users

Chris Barker — Fri, 07 Nov 2014 18:23:16 GMT

Grey haired brigade here.... Thiopentone came in 2.5g or 5g bottles 100ml sterile water -> 2.5% or 5% solution 2.5 % rarely gave perivascular sloughs but basically if I slipped outside the vein I always used to dilute the spillage by injecting 2-5ml saline around the vein and usually had no problem Dose 10mg/kg, reduced to 5mg/kg by ACP premedication (this was before the days of accompanying opiate!) Calculate the dose you think you need - put 150% in the syringe - give half of that as a bolus and top up to effect. Take as deep as you would with propofol/alfaxan Top up is possible but will prolong recovery progressively as the tissue/fat it gets distributed into to terminate anaesthesia become full. I was sad to lose Thio as an induction agent - before alfaxan appeared it was my choice for induction of animals with any cardiac insufficiency as it did not drop the blood pressure as other agents can do.

A very poor analgesic - indeed said to accentuate pain sensation. The worst recoveries for bitch speys I have ever witnessed were for a vet who was a excellent, speedy surgeon and who could perform a bitch spey in 20 minutes. However her anaesthetic of choice was incremental IV Thio, topped up as required. And even for 'short' procedures such as that it will require top-up. But the bitches climbed the walls in the kennels afterwards. When Phenyzene (our first injectable said - phenylbutazone) became available we finally had something to offer relief in the immediate post-op period

Never had an issue with greyhounds and Thio providing it was only being used for induction and they went onto gas. Brietal /methohexital was touted as being shorter acting and more suitable but was a far more 'vicious' drug, hard to balance and too swift of awakening. Sagatal / Nembutal was far too long lasting for routine anaesthetic use (one vet I knew used it IP for cat speys - they went home still asleep at the end of the day with instructions to turn them every hour until they woke up , which could be another 6-8hrs) but it was very useful for arresting status epilepticus when the animals (as always) refused to stop fitting even in the face of IV valium. I could tell you what a useful drug IV Sagatal could be for performing single handed caesareans when allied with small animal immobilon used a s a premed , but that it too historic to be of any relevance.....

So Thio holds few fears, but if there is no alternative to incremental top-ups some recoveries will be prolonged and a little violent (tremors/paddling etc)

Thio kept for weeks in the bottle when made up - if it recrystallised like others have said we threw it out.

Re: Calling thiodinovets and ket users

bob lehner — Thu, 06 Nov 2014 10:02:34 GMT

From memory on a WVS trip a while back we used xylazine/diazepam/alpha2/ketamine in various combinations. There was a good guide to field anaesthesia on the WVS website last time I looked.

Re: Calling thiodinovets and ket users

Bob Russell — Thu, 06 Nov 2014 10:01:25 GMT

Apologies. It was Brietal not Sagittal. Neither are available now!

Age is clearly getting to me! Time to retire?

Re: Calling thiodinovets and ket users

Anthony Todd — Thu, 06 Nov 2014 08:59:40 GMT

[quote user="Michael Woodhouse"]We used 2.5% and I never had a slough[/quote]

Yes, 2.5 seems to be sloughless but, with a big dog, you can need over 20mls so may have to change syringes also it takes a bit longer to get the dose in so you may have too much wriggling.

With cats and 2.5% you may need up to 5ml which makes handling the syringe and taping more difficult. [think 5ml syringes were centre nozzle as well, real pain to get them into cats' veins.]

From memory that was why we used 5%.

Still think you'll get more cost, hassle and extravasation with cannulas, and I can't see the point if you're just strapping one needle and syringe to the leg.

Extravasation occurred on multiple or misplaced vein penetration; once the needle was in it stayed in, trick was to penetrate low down on the leg so that if the leg was flexed the needle didn't penetrate the vein again.

Re: Calling thiodinovets and ket users

ruths — Thu, 06 Nov 2014 07:22:21 GMT

Be careful with alpha2s - drop the induction thio dose In the same way that you would with propofol. And I'm glad there's analgesia -)) I bet you can do a pretty quick spay anyway. Have you considered ovariectomy vs ovariohysterectomy?

Re: Calling thiodinovets and ket users

Linda Filshie — Thu, 06 Nov 2014 00:35:27 GMT

I used a lot of tramadol for bitch pre-meds when I did an overseas charity stint. It seemed to do a decent job of analgesia/reducing induction requirements though I know its efficacy is generally deemed questionable. It had the added benefit of being available from local pharmacies OTC.

It had a spectacular effect on one large pot hound whose heavy tick burden obviously felt the effects of the premed too and came flowing off the poor dog in a veritable ticky tide. Fun times

Re: Calling thiodinovets and ket users

David Mills — Thu, 06 Nov 2014 00:05:12 GMT

[quote user="John Flynn"]Do you know what with?[/quote]

I'm led to believe it tends to depend on what's available, but some alpha 2s are possible, and usually some sort of opioid (but not necessarily the two available together at the same time).

[quote user="John Flynn"]An interesting approach may be to mix-and-match? Depending on the set-up, I'd personally struggle to reliably spay each bitch in the 20-30min window that might be all afforded by either option on its own - in the scenario of being faced with needing "top-ups" of either ket/val or thio it might lead to less prolonged recoveries to switch drug at that point?[/quote]

Hmmm, yes I like this idea.

Re: Calling thiodinovets and ket users

Laurence Webb — Wed, 05 Nov 2014 23:57:12 GMT

[quote user="Malcolm Ness"]There was an ultra short acting barbiturate that the anaesthetists suggested for greyhounds the name of which escapes me for the minute (??methohexitone) but I am sure it wasn't Sagatal which I think is pentabarbitone - that would keep anything asleep for a comfortably long time!![/quote]

Not Sagatal then! Wikipedia suggests it may have been Brevital but that doesn't sound right.

[quote user="Malcolm Ness"]the thing to do is to calculate what you need then inject it in all at once - bang it all in![/quote] I stand corrected. I seem to remember giving about half to 3/4 rapidly then topping up if required. In thin dogs topping up was more cautious as they were sleepy for much longer. I also remember that rapid administration was useful as, if given slowly excitation and pain on injection (quite alkaline) were problems.

Re: Calling thiodinovets and ket users

John Flynn — Wed, 05 Nov 2014 22:57:50 GMT

[quote user="David Mills"]Yes there will be analgesia and dogs premedded.[/quote]

Do you know what with?

If xylazine and an opioid, then I would probably have gone with the ketamine option in this sort of setting? I generally dislike ketamine GA's in dogs, but with decent sedatives on board can work well - I'd be wary without an alpha-2 on board.

Choice of premed would significantly affect my dosing of the thio if going that route.

An interesting approach may be to mix-and-match? Depending on the set-up, I'd personally struggle to reliably spay each bitch in the 20-30min window that might be all afforded by either option on its own - in the scenario of being faced with needing "top-ups" of either ket/val or thio it might lead to less prolonged recoveries to switch drug at that point?

Re: Calling thiodinovets and ket users

Michael Woodhouse — Wed, 05 Nov 2014 22:23:12 GMT

I have lodged in my head 10mg/kg for thio. We had it when I graduated (2006) but it disappeared in the first year. I quite liked it.

We kept bottles open until they were used. We used 2.5% and I never had a slough and did get some outside the vein at times. Prefer propofol.

Re: Calling thiodinovets and ket users

David Mills — Wed, 05 Nov 2014 20:40:12 GMT

Thanks Ruth.

Yes there will be analgesia and dogs premedded.

Re: Calling thiodinovets and ket users

ruths — Wed, 05 Nov 2014 20:24:33 GMT

Obvs you need to know the concentration of the thio to work out the volume you need to give

Re: Calling thiodinovets and ket users

ruths — Wed, 05 Nov 2014 20:19:14 GMT

I agree with all the stuff above If you google lumb and jones anaesthesia book you can look at the thio page The dose here is around 10mg/kg but you give about half to two thirds as a quick bolus. It's really not like the slow trickle you do with propofol. In fact, when we changed over to propofol we used to see lots of apnoea at induction because we were so used to bolus injections. The Valium and ket isnt much fun as there's not much muscle relaxation and recoveries are quite unpredictable and the sofa are quite spacey. I agree re the eyes and the breathing- the latter can be quite weird. But - no analgesia with the thio?

Re: Calling thiodinovets and ket users

David Mills — Wed, 05 Nov 2014 20:04:15 GMT

[quote user="Malcolm Ness"]I have used thio as sole anaesthetic agent for speying bitches in Africa - this was charity clinic work and the bitches were all extremely thin and I would not advise it for that - there is little if any analgesia so they have to be kept relatively deep and the surgeon needs to be v quick and even then you get a slow recovery and a hung-over dog.[/quote]

This is what I'll be doing. Dogs will be tubed but no gas (ambi bag in case of problems). So in this situation I assume you would give a bolus of thio (calculated dose) and then top up as required?

What volumes do people use? e.g. the propofol rule of 4ml per 10kg for pre-medded animal

Re: Calling thiodinovets and ket users

Anthony Todd — Wed, 05 Nov 2014 18:31:14 GMT

Yes Sagatal was pentobarbitone [May and Baker] much missed by me and others for the control of epilepsy too.

Re: Calling thiodinovets and ket users

Anthony Todd — Wed, 05 Nov 2014 18:22:06 GMT

[quote user="David Mills"]Cannulae are used as mandatory in the set-up.[/quote]

I don't think we got many sloughs in dogs using sharp needles so cannulae seem like an unnecessary expense and are harder to enter a vein in one hit, IMHO, so I'd go for a simple needle.

[quote user="David Mills"]How long, technically, does thio keep for when reconstituted?[/quote]

Er, until the bottle is finished, just be careful to make up with distilled water or you get flocculation....

Re: Calling thiodinovets and ket users

Gillian Mostyn — Wed, 05 Nov 2014 18:09:07 GMT

In reply to the OP, I liked Thio and was quite reluctant to stop using it entirely. Like Malcolm said, it is given as a bolus NOT titrated so was nice to admin quickly to a wriggly dog. Experience told you how much you were likely to need. Recoveries were usually slower but that's not always a bad thing. I wouldn't go back to it now but liked it back then!

Re: Calling thiodinovets and ket users

Gillian Mostyn — Wed, 05 Nov 2014 18:01:48 GMT

The 'other thio' that has been referred to was not sagatal- it was (as Malcolm thought) methohexital/one, sold as 'brietal'. I used it as a student (practice did a lot of racing greyhounds) and it also had to be given quickly as a bolus. I had to give it off the needle and if you didn't get the whole dose in the dog had seizure-type movements and getting another IV was awful.

Re: Calling thiodinovets and ket users

Yantha Smyth — Wed, 05 Nov 2014 17:50:42 GMT

In my first job after graduation our routine induction for dogs was valium/thio, and for cats was ketamine/valium.

We did use ket/val in some dogs, when thio contraindicated too.

There was a lot of salivation when ket/val was used alone, however in those days our premed was including atropine (acp/morphine/atropine)

We would draw up 0.1ml per kg each of ket and val combined in one syringe. Usually give 50% of this as initial IV bolus, then wait a good 20s for full effect before considering giving any more. Rest could be used as top-up, though we tended to then intubate and have on gas.

Both cats and dogs but possibly more so for cats- inspiratory apneustic pattern often seen with ket.val- holding their breath, but breathe out instantly with a brisk single tap on the nose

Eyes tend to stay open more with the ketamine, so ensure plenty ocular lubrication.

ketamine handy also as will work by ANY route- so if particularly fractious can squirt into a hissing or snarling mouth and get some degree of control to enable IV access

thats all i can think of, hope it helps!

yantha

Re: Calling thiodinovets and ket users

Malcolm Ness — Wed, 05 Nov 2014 17:44:29 GMT

[quote user="Laurence Webb"]For that reason you would want to use minimum amounts to effect in thin dogs rather than just banging in a calculated dose (not that you would do that anyway). [/quote]

Therein lies the problem, I think.

As Evelyn has pointed out, ACP markedly reduces the necessary dose so when using thio for induction, the thing to do is to calculate what you need then inject it in all at once - bang it all in! You get a brief period of anaesthesia enough to allow intubation and induce anaesthesia with the gaseous agent (it was usually halothane). Slow injection and titration of the type that has become the norm with propofol resulted in the use of a (very) much larger dose of thio. The drug is initially relocated into body fat, hence the greyhound story which, as Lawrence points out is related to low body fat and not breed. The propensity of thin dogs to sleep for an extended time is exaggerated - on occasions a neophyte vet missed the opportunity to get a tube down and had to repeat the induction with a full second dose - the dog was groggy for longer but not unduly so. With racing greyhounds, the dogs typically made a nice smooth recovery from thio induced GA and would be up and able to walk to the owner's van (greyhound people always have vans rather than cars) the same evening.

I have used thio as sole anaesthetic agent for speying bitches in Africa - this was charity clinic work and the bitches were all extremely thin and I would not advise it for that - there is little if any analgesia so they have to be kept relatively deep and the surgeon needs to be v quick and even then you get a slow recovery and a hung-over dog.

[quote user="Laurence Webb"]I did move over to Sagatal for greyhounds[/quote]

There was an ultra short acting barbiturate that the anaesthetists suggested for greyhounds the name of which escapes me for the minute (??methohexitone) but I am sure it wasn't Sagatal which I think is pentabarbitone - that would keep anything asleep for a comfortably long time!!

Re: Calling thiodinovets and ket users

Hannah Wynne Richards — Wed, 05 Nov 2014 16:54:40 GMT

It will keep a few days in the fridge - but I don't know if fridges are going to be available, or the environmental temp of the area! All inductions, including at uni were thio when I qualified. They slept for far longer than with either propofol or alfaxan even if thio only used for induction. You'll have to be a seriously speedy surgeon to complete a spay without topping up! I certainly couldn't

Wynne

Re: Calling thiodinovets and ket users

Evelyn Barbour-Hill — Wed, 05 Nov 2014 16:29:03 GMT

[quote user="David Mills"]Unsure of the concentration of thio.[/quote]

That should surely not be a problem for you, if there's water for injection available you can use what you want. Some people went to 1.25%.

[quote user="David Mills"]How long, technically, does thio keep for when reconstituted?[/quote]

Ah.

We never worried, we just used the bottle till it was gone, which admittedly did not take long. If it looked murky or there seemed to be any crystallising out, we threw it away, but I don't remember needing to do that.

It also sometimes came in glass vials (with a little saw in the box to saw the glass before you broke it, remember that?) but we weren't so skanky as to try and keep those half-used.

Re: Calling thiodinovets and ket users

Laurence Webb — Wed, 05 Nov 2014 16:26:59 GMT

From memory, thio recovery is primarily by redistribution into fat. Having such a low fat index is what makes Greyhounds sleep so long, not necessarily their breed. The metabolism of thio is fairly slow so you get longer hangovers with it. For that reason you would want to use minimum amounts to effect in thin dogs rather than just banging in a calculated dose (not that you would do that anyway). I used to give about half the calculated dose as a bolus then the rest to effect. You would not need to top up a thin dog as much as it won't redistribute into fat as much. Long procedures needing multiple top-ups will probably have a fairly long recovery.

I used to use it in greyhounds and they were generally OK but would be sleepy for a day or two (most were well enough to go home the same day but some needed to be kept in overnight). I did move over to Sagatal for greyhounds but as the price of propofol dropped it became less important.

I can't remember how long a made-up bottle should be kept but it was normal practice for a bottle to be used until empty. Blowing the dust off a bottle that had been made up then hidden at the back of a cupboard may have occurred on occasion

Re: Calling thiodinovets and ket users

Evelyn Barbour-Hill — Wed, 05 Nov 2014 16:18:53 GMT

[quote user="Anthony Todd"]Back then we used Themalon[/quote]

Ah, happy days.........

We usually used acepromazine as a premedicant for dogs (straight, not with an opiate), the rule of thumb as I recall being that it halved the dose of thiopentone. Some people pre-medded cats, but I did not.

Greyhounds and other minimally-fat dogs did sleep for considerably longer than others, but only overnight.

I'm sure that the patient had a considerable hangover after thiopentone; didn't fully realise this until I'd tried propofol.

It's a good deal easier to kill a patient with thiopentone than with propofol but any experienced veterinary surgeon can manage the doses. Just be careful to be sure whether you have 2.5% or 5% in the syringe!

[quote user="Anthony Todd"]

Of course if the OP wants to go one better and use iso or halothane Stevens machines can probably be had for nothing, as they are out of favour, but ideal for use in the bush provided you can get O2 and they use very very little iso or halothane compared with "modern" machines.

[/quote]

This is true but the user will need some training in its use, if accustomed to an out-of-circuit vaporiser, and the machine does need a certain amount of maintenance, and soda lime will be needed as well as oxygen.