Rabbit anaesthetics - searching for the best options

RE: Rabbit anaesthetics - searching for the best options

Richard Saunders — Thu, 04 Feb 2021 14:34:40 GMT

i think thats a REALLY important point. The premed is crucial in terms of the effects of the Alfaxan, and i think that the lighter premeds and higher alfaxan doses are more likely to give one a degree of conscious breath-holding, as well as all the other benefits of balanced anaesthesia/analgesia

RE: Rabbit anaesthetics - searching for the best options

Edward Jones — Thu, 04 Feb 2021 14:28:17 GMT

I use medetomidine 0.15mg/kg + buprenorphine 0.03mg/kg as premed i/m, followed by i/v alfaxan 0.5-1mg/kg to induce and 0.5% isoflurane initially.

I never get any apnoea, it's a quarter of the licensed dose of alfaxan - I find a medetomidine premed particularly dose-sparing for alfaxan in all species.

RE: Rabbit anaesthetics - searching for the best options

Catherine Spence — Wed, 03 Feb 2021 13:35:12 GMT

Yes, thanks, very helpful.

RE: Rabbit anaesthetics - searching for the best options

charlievelyn — Wed, 03 Feb 2021 09:45:35 GMT

Thanks Richard Saunders for replying, great to have your input!

RE: Rabbit anaesthetics - searching for the best options

Richard Saunders — Wed, 03 Feb 2021 08:52:18 GMT

I use the same as Charlotte, above ( triple, 0.1ml/kg medetomidine 0.03ml/kg each of butorphanol and ketamine given i/v), with the modifications of giving it via iv cannula, and substituting buprenorphine at 0.05mg/kg IM (0.03mg/kg in giant breeds) 30 mins earlier for the butorphanol, if I think the analgesia from the 1mg/kg meloxicam and local is likely to be insufficient, or with methadone at 0.5mg/kg in place of the butorphanol at the same time as the med/ket, if i think i need that level of opioid pain relief. Whilst it gives good sedation and excellent analgesia, methadone, IMO, demands better pain scoring to decide when further analgesia is required.

I'm also not discounting the analgesic effects of the alpha 2 and the ketamine used in lot of triple combos, and if using alfaxan, thats got to be replaced with some effective, multimodel, pre-emptive analgesia

I can certainly see the logic of a considered approach to when to place an ET tube, when to use a v-gel, and when to use a tight fitting mask, depending on the procedure, ASA score, and personal experience with each method. i would argue though, that you only become practiced doing something through, well, practice, and an apnoeic rabbit with no iv access is not the best one with which to start learning how to intubate.

For other cases, Id modify those doses, or use hypnorm (where available; opioid/alpha2/benzo if not)/alfaxan.

Increasingly I'm using tramadol and gabapentin (more chronically), paracetamol, and maropitant. Good nursing is worth a pint of morphine.

I'd slightly disagree that most practices dont use opioids in rabbits. In every anecdotal survey i carry out, approx 2/3rds to 3/4s use a triple, containing an opioid, and over the past 10 years or so, Ive seen buprenorphine start to gain or butorphanol in those triples. I think that many practices are still cautious about opioids and GI motility, but that at appropriate doses and durations, they are safe, and nothing stops gut motility more than pain, especially abdominal pain.

Rich

RE: Rabbit anaesthetics - searching for the best options

Clive Ansell — Tue, 02 Feb 2021 18:45:33 GMT

Richard, what's you preferred anaesthetic drug(s) for an outwardly healthy rabbit under going a straightforward procedure such as neutering?

[quote userid="11719" url="~/001/veterinary-clinical/exotics/f/discussions/29634/rabbit-anaesthetics---searching-for-the-best-options/228292#228292"]why dont you routinely use opioids? Both effective in terms of analgesia, and sedation![/quote]

Many practices seem not to use opioids in rabbits, whereas they routinely do in cats and dogs. I've never understood the reasoning for it.

RE: Rabbit anaesthetics - searching for the best options

Richard Saunders — Tue, 02 Feb 2021 16:56:53 GMT

why dont you routinely use opioids? Both effective in terms of analgesia, and sedation!

I think if a patient feels the surgery, there is something wrong! local on the spermatic bundle takes seconds, if you want to avoid further systemic drugs

20 years ago, people didnt bother tubing cats. Time moves on...

A well maintained stable anaesthesia is safer than a short, unstable one with rocky induction and recovery and noxious stimuli throughout. I totally accept that speed is a factor, but this is a matter of minutes difference, and the most dangerous bits of a GA are the beginning and the end, extending the middle part by a few minutes is well worth it for a stable anaesthetic, a good recovery, and a rabbit that is well analgesed afterwards.

RE: Rabbit anaesthetics - searching for the best options

Sarah Keir — Mon, 01 Feb 2021 20:25:30 GMT

I feel the safest GA in a rabbit (apart from not doing one) is to have stress/handling to a minimum and have a secured airway.

I'm very glad Saffan disappeared from use, though I can remember using thio for the first couple of years of vetting.

RE: Rabbit anaesthetics - searching for the best options

Julian Earl — Sun, 31 Jan 2021 23:13:57 GMT

[quote userid="9515" url="~/001/veterinary-clinical/exotics/f/discussions/29634/rabbit-anaesthetics---searching-for-the-best-options/228154#228154"]nduced apnoea, no matter the premed or how little I gave. Would be interested to see if anyone else seen this effect.[/quote]

Hello Sarah, Yes we used to see it often [ every time?] that we used Saffan on rabbits via the ear vein. I always regarded rabbits as very high risk patients for GA with Saffan in particular. We switched to masking them down with halothane initially but later changed to isofluorane instead which seemed much better and safer.

RE: Rabbit anaesthetics - searching for the best options

Charlotte Marshall — Sun, 31 Jan 2021 22:52:16 GMT

I use triple, 0.1ml/kg medetomidine 0.03ml/kg each of butorphanol and ketamine given i/v just through a needle. I use a reduced dose for older bunnies for dental etc. We do usually tube them may need abit of iso especially the spays (I don't tube the dentals)

RE: Rabbit anaesthetics - searching for the best options

Sarah Wheadon — Fri, 29 Jan 2021 10:10:55 GMT

Another vote for triple, my doses slightly lower - medetomidine 0.1ml/kg, ketamine and butorphanol 0.05ml/kg after meloxicam/metoclopramide premed. Then intubate and iso/02. Has worked very well for me for >20 years, so although it may seem old fashioned, I'm happy to continue.

RE: Rabbit anaesthetics - searching for the best options

Clive Ansell — Fri, 29 Jan 2021 10:03:41 GMT

[quote userid="3169" url="~/001/veterinary-clinical/exotics/f/discussions/29634/rabbit-anaesthetics---searching-for-the-best-options/228185#228185"]don't own V gels, don't mess about with tubing. Get it asleep, done ASAP and awake. My feeling is that bunny surgery success = speed.[/quote]

Agree.

It seems to be becoming the way of doing things in many practices now; as much faffing as possible. I recently witnessed a cat spey taking 1 and 1/2 hours - unable to get pre op bloods - homeopathic doses of acp/buph premed - unable to place iv cannula - EMLA cream and bandage and wait 20 minutes - still unable to do - both cephalics buggered - cat now stressed +++ . Finished up triple combo, which is what I would have done in first place.

RE: Rabbit anaesthetics - searching for the best options

Clive Ansell — Fri, 29 Jan 2021 09:55:00 GMT

[quote userid="12930" url="~/001/veterinary-clinical/exotics/f/discussions/29634/rabbit-anaesthetics---searching-for-the-best-options/228162#228162"]

What doses of triple do you use that you find safe and effective for rabbit neutering?

Is this IM or SC?

Are these doses sufficient for a castrate +/- spay proceudure with only oxygen supplementation in the average rabbit, or is iso generally necessary also?

[/quote]

There seems a massive variation in doses used. I tend to use lower doses than most, usually 0.1 ml per Kg each Medetomadine and Ketamine, plus Buph at 0.1ml per 1.5 Kg. I find smaller rabbits need more, so wonder if it is weight dependant ?

Prefer IM dosing, but s/c seems to work just as well in Rabbits

Very rarely intubate or place iv cannulas, although might for long ops, but always mask oxygenation +/- iso/sevo as needed. Can usually castrate with just o2. Routinely use an opiate, either Buph or Metadone, and Metacam at Rabbit dose given pre op. Keep them well monitored, and warm during recovery. usually give s/c fluids.

Almost always reverse Medetomadine, and don't routinely give Baytril or Metoclopramide. Most recover quickly and uneventfully and are eating well before they go home. Works well.

RE: Rabbit anaesthetics - searching for the best options

Michael Woodhouse — Thu, 28 Jan 2021 22:22:04 GMT

Beats yes we use similar doses, but medetomidine and ketamine and give meloxicam. Don't routinely use opioids in bunnies.

They kick when you ligate spermatic cord, but shouldn't need iso.

I find my self looking at a 3kg bunny, holding a syringe that would incapacitate a great Dane and wonder if I've cocked up with my dose somewhere.

(don't own V gels, don't mess about with tubing. Get it asleep, done ASAP and awake. My feeling is that bunny surgery success = speed.

RE: Rabbit anaesthetics - searching for the best options

Beats — Thu, 28 Jan 2021 21:11:13 GMT

[quote userid="11308" url="~/001/veterinary-clinical/exotics/f/discussions/29634/rabbit-anaesthetics---searching-for-the-best-options/228173#228173"]We use triple combinat[/quote]

Doses?

There is a HUGE variation in doses of "triple" that are recommended / used so far as I can see.

I'll start the ball rolling with "young healthy rabbit castrate dose, high with view to not masking with iso or intubating":

0.25mg/kg medetomidine [0.25ml/kg]

15mg/kg ketamine [0.15ml/kg]

0.4mg/kg butorphanol [0.04ml/kg]

IM in 2 x sites either side of lumbar spine.

usually enough for a rabbit castrate with just oxygen given (in my very limited experience), wasn't today.

Source = Self-assessment color guide to rabbit medicine and surgery (edited Anna Meredith?), 1st edition i think.

This is about the highest doses of "triple" that I've come across being recommended in modern times; most sources recommend substantially lower doses, which I assume to be aimed more at "induction" prior to giving iso/sevo.

RE: Rabbit anaesthetics - searching for the best options

Anthony Dennison — Thu, 28 Jan 2021 13:55:55 GMT

We use triple combination given SC, then once asleep place a V-gel if possible. Definitely enough to do a castrate, normally our spays get a little bit of iso (very low, normally 0.5%.max).

There is a 'healthy' rabbit dose and an 'old/sick' rabbit dose that we use, but not sure where we got it from.

RE: Rabbit anaesthetics - searching for the best options

charlievelyn — Thu, 28 Jan 2021 11:27:41 GMT

I had a couple of apnoeic rabbits on Alfaxan which has put me off using it. I've been having good success recently in healthy rabbits with SC buprenorphine at least 1 hours before catheterisation followed by IV medetomidine and ketamine (diluted) to effect, then intubation and maintenance on Sevo. Haven't tried midazolam but would like to try, though I do like knowing I can reverse the medetomidine!

RE: Rabbit anaesthetics - searching for the best options

Beats — Wed, 27 Jan 2021 20:43:28 GMT

Clive Ansell

What doses of triple do you use that you find safe and effective for rabbit neutering?

Is this IM or SC?

Are these doses sufficient for a castrate +/- spay proceudure with only oxygen supplementation in the average rabbit, or is iso generally necessary also?

RE: Rabbit anaesthetics - searching for the best options

Clive Ansell — Wed, 27 Jan 2021 20:02:11 GMT

Been using triple combo for year; medetomadine, Buph or methadone, Ketamine with o2 +/- isoflurane/sevo for years with no issues at all. Metacam at rabbit doses for routine surgeries.

I've worked in practices that use Propofol or Alfaxan, but they do seem to have problems with apnoea with both.

A rabbity (in more ways than one) nurse recently told me that triple combo was old school and outdated - yet it is safe and reliable, and what her practices uses seems more problematic and takes far longer, with far greater faff factor.

RE: Rabbit anaesthetics - searching for the best options

Sarah Keir — Wed, 27 Jan 2021 18:09:27 GMT

I don't have a great amount of experience of using Alfaxan in rabbits but I found that it invariably induced apnoea, no matter the premed or how little I gave. Would be interested to see if anyone else seen this effect.