Sevoflurane

RE: Sevoflurane

PSA-David — Fri, 27 Jan 2017 13:16:01 GMT

[quote user="Susanna Taylor"] Regarding changing the vaporiser setting during painful episodes, please only do this as short term to prevent the patient jumping off the table.. it's not analgesic and it is not truely helping the patient. Ask your vet to let it have more analgesia. Nitrous, ketamine, medetomidone or fentnayl boluses will all work much better! Sorry for long post, but hope it helps.[/quote]

this i understand totally, and if the situation myself or anyone would request further analgesic. however this was the instructions form Abbott when the product was first introduced.

RE: Sevoflurane

Susanna Taylor — Fri, 27 Jan 2017 09:40:58 GMT

Hi Regarding renal toxicity and sevo- in dry soda lime sevo degrades in to a substance called Compound A, which has been shown to be renal toxic in rats. I don't think it has been shown either way in cats, but the assumption seems to be that it would also be toxic. This is the route of the statement in the data sheet In clinical terms, if you used closed circle technique in cats, the sodalime would likely remain quite dry as cats TV is so small (there will be little water produced in the sodalime). That, plus the recircling of gas could cause compound A to accumulate. The BSAVA manual states it should not be a problem if suitable flow,rates are used. It does into detail about this in chp5. In general, I personally would not use less then 0.5-1L depending on the size of the circle. Regarding MAC, as mentioned, it is calculated using no other drugs. Therefore, we should expect to be using less with adequate analgesic protocols. Also, MAC is the %breathed out, (i.e. Alveolar) This is NOT the same as the vaporiser setting. If you measure inspired and expired levels, there will be about 0.5% difference initially and over time they will slowly equilibriate. (Which is why we turn down slowly when settled) On the practical side, when using sevo, I have found I have generally been working about 1-1.5% higher of sevo then I would do with iso- so for instance, if I felt I would start a case on 2%iso (after checking its post induction depth) I would start it on 3%sevo. I know this is a bit untechnical, but it works! MAC provides us with ball park figures really, - the only way you know you have it right is by monitoring your patient and adjusting as necessary Although sevo does have a lower blood:gas coefficent, it is not massively clinically noticeable, but makes a strong case for using it in peads, brachys, rabbits, and gasing anything down if really required. Regarding changing the vaporiser setting during painful episodes, please only do this as short term to prevent the patient jumping off the table.. it's not analgesic and it is not truely helping the patient. Ask your vet to let it have more analgesia. Nitrous, ketamine, medetomidone or fentnayl boluses will all work much better! Sorry for long post, but hope it helps.

RE: Sevoflurane

PSA-David — Thu, 26 Jan 2017 13:47:55 GMT

hi I know this is an old thread, but can i just double check something. people are not placing the animal on Sevoand leaving it as a straight level during anaesthesia. As Sevo is a gas that works within seconds, so its used to dose to the level of pain stimuli's, for instance, the tug on the ligament during a spay, increase slightly before and then reduce after the "pain" is over".

not like I have seen some nurses do with this product and others, wait till the animal show pain and the increase... as in my mind you should be pre adjusting for anything you know will impose a pain feeling to the animal,

your anaesthetic Sevo chart will be up and down like sound wave. but then this is reflected by a consistent heart rate and resp rate

RE: Sevoflurane

Courtney Scales — Mon, 23 Jan 2017 19:45:26 GMT

Hi Nickyvn - they have seen renal toxicity in rats, but it shouldn't really be a problem when correct FGFs are used in a circle system.

Only 3% is biotransformed in the liver (the rest is taken in and exhaled in each breath) so the kidneys don't actually have much to do with the metabolism.

One reason they may suggest renal damage is due to the hypotension inhalants can cause, and then we pop an NSAID into the mix too where potentially the kidneys have not been perfused very well under GA. I don't think it is directly related to the Sevo itself.

RE: Sevoflurane

Nicola Smith — Mon, 23 Jan 2017 19:15:05 GMT

We have recently reread the sevo small print and it states kidney damage can occur in prolonged ga especially with low flow rates. Does anyone know is this specific to sevo or is this for all gas. Also we use circles routinely therefore low flow rates - how does this affect risk of kidney damage and any way of avoiding this??

RE: Sevoflurane

James Colver Cert. Ed, RVN — Mon, 23 Jan 2017 18:25:31 GMT

Seconded - can't believe what I'm reading. People are still gassing down cats?!

RE: Sevoflurane

Courtney Scales — Mon, 23 Jan 2017 17:49:51 GMT

Although an old thread - this might help some new Sevo users!

Are you familiar with MAC? (Minimum alveolar concentration). Understanding the concept of MAC, and then knowing what the MAC of isoflurane and sevoflurane will help you to wrap your head around handing the different % (between sevo and iso) when working in your new place.

MAC: this "number" tells us potency of inhalants, and is especially useful when comparing different agents (Sevo vs Iso). The definition is that MAC (the % setting on your vaporiser) will keep 50% of patients anaesthetised when a painful stimuli is inflicted. For the other 50%, they will respond. However, this is in the absence of any premedications and doesn't take into account the patients own biological stats (age, disease processes).

For comparison;
MAC of Isoflurane is 1.7 in cats and 1.3 in dogs. (1.7% and 1.3%)
MAC of Sevoflurane is 3.0 in cats and 2.3 in dogs. (3% and 2.3%)

Remembering that this will only keep 50% of patients anaesthetised to the point of being non-responsive to painful stimuli, we have to add a factor of x1.3 to the MAC to make sure 95% of patients will not be responsive. This means your vaporiser may have to be a little higher:

1.3 x MAC of Isoflurane is 2.2 in cats and 1.7 in dogs.
1.3 x MAC of Sevoflurane is 3.9 in cats and 3 in dogs.

So now you have a guide between 1x MAC and 1.3x MAC to work from. MAC can actually decrease due to a number of factors:

sedatives (premeds)
opioids (in premeds)
old age
hypothermia
etc..

Therefore, I will hardly ever have a cat on 3.9%+

It really is a great inhalant.

Good luck :)

RE: Sevoflurane

F1chick — Fri, 13 Jan 2017 21:10:58 GMT

I know this is a really old thread, but is there any online CPD on Sevo??

I am swapping to sevo from using Iso all my life (except from Halothane) But I'm fining he transition hard

Re: Sevoflurane

Stella Skelton RVN — Sun, 17 Oct 2010 12:51:34 GMT

We use Dom-Ket to knock out cats then Sevo to maintain...usually works well...better than Alfaxan and Iso in my last practice...i hate Alfaxan...patients go nuts on recovery...to the point where one dig bit his tongue getting blood everywhere...cats wake up quite well on Dom-Ket and sevo...a little jittery...but probably because of the ketamine...although we do wait before giving them anti...i also didn't know sevo wasn't licensed for cats!!

Re: Sevoflurane

Stuart Ford-Fennah — Mon, 23 Aug 2010 16:58:25 GMT

Hi Elizabeth

I regards to your question what seeting are 'the same' well MAC of iso is about 1.5% in dogs and cats +/- about 0.05 depeding on what study you read, and the MAC of Sevo is 2.5% (again +/- a bit) and dependant on what book/paper you read, varies abit with species but not much, essentially, it provides less cardivascular and respiratory depression, therefore - if you run them a bit high, you dont get the same depression as you would with iso (or halothane if youve ever had the joy).

Hope that helps a little,

Stu

Re: Sevoflurane

Claire Cameron — Mon, 23 Aug 2010 15:57:40 GMT

[quote user="Sandra Taylor RVN, MBVNA"]Sevo is not licensed in cats as far as I am aware[/quote]

Yup, you're right Sandra,

"Target species

Dogs."

[quote user="Sandra Taylor RVN, MBVNA"]you cant use in in pregnant bitches either.. as it's not licensed for that either.[/quote]

"Contraindications

Do not use in pregnant and lactating bitches (see Use during pregnancy or lactation)."

http://www.noahcompendium.co.uk/Abbott_Laboratories_Ltd/SevoFlo/-40328.html

Re: Sevoflurane

Kim Buckley — Sun, 22 Aug 2010 21:13:14 GMT

In one of my previous practices we would gas down cats if we were unable to get a vein. We never used triple combo as it wasn't practice policy.

Sevo was definately a lot quicker for this and didn't freak them out as much as iso. I'm not saying I agree with it at all but that's the way it was.

Re: Sevoflurane

Honeybadger — Sat, 21 Aug 2010 22:12:46 GMT

I have worked with Vets that has gassed down cats. Usually they have had a very small amount of propofol IV and then the vein has blown so they use iso, o2 and a mask to get them deep enough to allow ET intubation. They are usually a bit sleepy already so dont react badly to it.

Re: Sevoflurane

Vicky RVN — Sat, 21 Aug 2010 22:08:48 GMT

We tend to use i/m triple in a crush cage if we can't get near cats for an i/v. Did used to gas box but not done it in aaaaaages thankfully.

Re: Sevoflurane

Mrs Dot Dot — Sat, 21 Aug 2010 22:06:23 GMT

[quote user="ursula bradshaw"]

The great thing about it is you can whack it up to 8 for a couple of minutes to get the animal asleep without having to worry too much.

With this in mind it's great for gasing down fractious or old cats, also young animals (coz it is the inhalation anaesthetic for children in hospitals as well).

[/quote]

How often do you gas down cats?? Occassionally use to do it years ago but surely there is no need to do it these days with all the options available?? From a H&S point of view for the nurses/vets... long term low dose use/ exposure to any drug is not good and we are top of the list for things like this and also from a stress point of view for the cat... from what I remember it was always a scary thing to do because they use to panic / major stress etc and I would never want to be involved with doing it now. There are other safer, less stressful, healthier ways of g/a'ing a cat sucessfully.

I am genuinely shocked at this... I have to say I have never used sevo so cannot comment on its use/ effects etc but even saying 'you can whack it up to 8' sounds very scary to me and again not quite the right thing to do??

Do many other practices gas down cats?

Re: Sevoflurane

Sandra Taylor RVN, MBVNA — Sat, 21 Aug 2010 21:49:20 GMT

Sevo is not licensed in cats as far as I am aware... and you cant use in in pregnant bitches either.. as it's not licensed for that either.

You need higher % with sevo and you need to keep dropping it down and challenging it, ever so slightly, but watch they waken quickly so if they are too deep dont knock it down too much.. or they will waken.

I actually quite liked it to be fair and the recovery I noticed there was not that howling /whingeing that you get with iso

Re: Sevoflurane

rachel w — Sat, 21 Aug 2010 20:11:19 GMT

lol,

Re: Sevoflurane

Caro Laithwaite VN — Sat, 21 Aug 2010 19:13:20 GMT

Easy... Give Rottie whalloping big dose of Dom first

Re: Sevoflurane

rachel w — Sat, 21 Aug 2010 18:42:10 GMT

We tend to maintain on 2%, with o2 and nitrous, we only have sevo in the practice i changed from an iso only practice to a sevo only practice a few yrs ago, took a while to get used to the quicker change in the patient when changing the %, but now i find the thought of going to iso just as bad, we only tend to gas down our patients if everything else fails i always remember a rep coming to my old practice and one of there selling points was that u could gas a rottie down with 8 big breaths now i have never seen this happen but would love to know how they managed that!!

Re: Sevoflurane

Laura James — Sat, 21 Aug 2010 16:39:46 GMT

Personally I wouldn't gas down cats - most dont appreciate the smell of the Sevo when masking them down and dont have a smooth recovery. I tend to maintain on 2-3% depending on the animal and how much induction agent they have had. When using with nitrous i have had patients on 1% maintainance

Re: Sevoflurane

Emma Gerrard Dip AVN (SA) DipHe CVN BSc (Hons) CVN RVN KSQP RAM — Sat, 21 Aug 2010 15:34:02 GMT

I have been in my new practice for three weeks and we use sevo. We tend to use it at 3% for maintainence. I would always use iso at 2% per maint. I definatley find that a higher percentage is needed to maintain anesthesia. Having said that the vapuoriser needs to be topped up much less than with iso.

Re: Sevoflurane

Rachel Jayne — Sat, 21 Aug 2010 14:55:45 GMT

You think it's good for gassing down cats....?

In my experience, cats go absolutely up the walls on recovery after wrestling to mask them down with Sevo....

Re: Sevoflurane

ursula bradshaw — Sat, 21 Aug 2010 11:49:13 GMT

We have one sevo unit in our practice. I don't use it a lot, and I don't think it's as great as people say it is. It is slightly different to iso though, and I wouldn't say you could make similarities with them with % etc. The great thing about it is you can whack it up to 8 for a couple of minutes to get the animal asleep without having to worry too much.

Whereas with iso it could take a few minutes to see a change if you turn them up or down, sevo is far more sensitive so be careful with this. As with iso you want to have them on the lowest possible for surgery, I find that I usually start with them on 4 (2 litres o2) and, depending on the surgery, can have them down to 2. The rep reckoned you could have them on 1.5.....not had this happen yet, they usually tend to be waking up at that point!!

They wake up a lot quicker from sevo as well which is lovely. It doesn't smell as badly, I think I can smell it, although a lot of people cannot! With this in mind it's great for gasing down fractious or old cats, also young animals (coz it is the inhalation anaesthetic for children in hospitals as well).

Think that's all I can say, I hope that helps a little?!