Mask isoflurane - what is the consensus these days?

RE: Mask isoflurane - what is the consensus these days?

Gillian Mostyn — Wed, 02 Aug 2023 12:04:15 GMT

[quote userid="8663" url="~/f/clinical-questions/30729/mask-isoflurane---what-is-the-consensus-these-days/241991#241991"]However, one issue with the approach of considering only a risk to pregnant staff is, how can you be certain who is or is not pregnant? The answer isn’t obvious: greatest risk is often before pregnancy is confirmed [/quote]

Absolutely. All women of child bearing age have to be assumed to be pregnant - as by the time you know, its too late to start putting in precautions!

[quote userid="3169" url="~/f/clinical-questions/30729/mask-isoflurane---what-is-the-consensus-these-days/241997#241997"]
One of the biggest risks is actually post intubation as the dog breaths out the iso, in all ops.[/quote]

I was told many years ago that the area with the highest levels of exhaled anaesthetic gases is the kennels? I had this discussion once with a pregnant nurse who asked to stay out of the op room, but was spending a significant amount of time in the kennels instead. I was concerned she was putting herself at even more 'risk'. Whether this is now less of an issue with iso than it was with halothane I don't know.

RE: Mask isoflurane - what is the consensus these days?

Clive Ansell — Fri, 28 Jul 2023 20:50:37 GMT

Agree with the posts so far.

There should rarely be a need to do it, we know it is potentially toxic so it's easy to use careful as far as possible. The issue of pregnancy should not even enter the equation, it is know to be potentially harmful so EVERYONE should be protected as far as is possible.

I tend to prefer planned anaesthesia over sedation anyway; patients intubated, oxygenated, and fully monitored. I tend to use triple or quad combo in cats, intubate and iso as/if needed, but rarely is for most routine ops. The only exception being cat castrations because they are so quick.

I once worked in a practice that dealt with a lot of Shar Pei's. Many were aggressive. Most vets would use dom/torb premed and gas down as so difficult finding veins. I found dom/opiate/ketamine worked better and was more reliable.

RE: Mask isoflurane - what is the consensus these days?

Nicola Cole — Thu, 27 Jul 2023 20:08:36 GMT

Having been pregnant whilst working in 2 (very) different practices, it was actually quite interesting to see the differences. The amount of iso exposure in the first practice was significant, and there were a number of other things that had to be moderated/avoided during my pregnancy. During my second pregnancy the only thing I had to avoid was gassing down an injured but very feisty squirrel, and a couple of specific medicines by injection.

I personally believe that iso exposure is actually very easy to limit if appropriate precautions are taken. So why should we be risking it? We should be presuming that any woman of child bearing age could be pregnant (the greatest risk of X-rays for example is during embryo implantation I believe, so well before a woman would know).

What is the risk to non-pregnant individuals? I’m not sure there’s been any widescale studies done (I certainly did a paper search when I was pregnant and don’t remember finding anything much but stand to be corrected)-but it’s so easy to avoid that why should we be taking the risk? I know iso exposure used to give me headaches-so even if only short term side effects-why should we risk them if avoidable?

And yes, post intubation is the main risk as far as I’m aware if all other health and safety things are properly in place (although I’ve never knowingly smelt iso during this period, whereas during mask anesthesia in the first practice, I certainly have!).

So, for me-avoid the avoidable, as who knows what longer term risks there are! n=1

RE: Mask isoflurane - what is the consensus these days?

Michael Woodhouse — Thu, 27 Jul 2023 16:09:03 GMT

Its just not the kind of medicine I want to be practising. The only time I'd consider it was for something small and difficult (exotics in a chamber).

I know of a practice where lots of animals are pre-medded and then gassed down by the nurses, as they are allowed to do that.

I remember one dog a few years ago where we couldn't get IV access and did gas down, but it will be one dog/cat in the last 10 years for me, so not a regular occurrence.

Sometimes do give cats under triple a bit of O2 and iso if getting light, and then we turn on fans and make sure the mask is well fitting. I don't expect to smell iso.

One of the biggest risks is actually post intubation as the dog breaths out the iso, in all ops.

RE: Mask isoflurane - what is the consensus these days?

Alasdair Hotston Moore — Thu, 27 Jul 2023 01:51:09 GMT

I don’t think an absolute ban is required. However, one issue with the approach of considering only a risk to pregnant staff is, how can you be certain who is or is not pregnant? The answer isn’t obvious: greatest risk is often before pregnancy is confirmed