Low flow anaesthesia. Is it worth it?

RE: Low flow anaesthesia. Is it worth it?

Michael Woodhouse — Mon, 16 Feb 2026 23:27:52 GMT

[quote userid="12930" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248384#248384"]Doesn't seem to answer the question on whether an Aldasorber is considered a good thing or not? I still haven't found anything on this.[/quote]

We havn't used them for years, but we used to seal in a bag and send with crem waste and be charged a similar amount for disposal as we paid to buy them. Some google sources suggest the anaesthetic gasses can be somehow removed from the device, some devices (think US) suggest you can just throw them in your normal bin!

https://www.vetamac.com/activated-charcoal-canisters-you-asked-we-listened/?srsltid=AfmBOoo0_bXOVgiAvzC153u0uK0BpDb5C1SYyuMzExuusobMxEdAiern

RE: Low flow anaesthesia. Is it worth it?

Beats — Mon, 16 Feb 2026 21:18:43 GMT

Thanks for link, Rob.

Doesn't seem to answer the question on whether an Aldasorber is considered a good thing or not? I still haven't found anything on this.

Purely from an environmental stand-point, it would seem to be a reasonable question on whether the incineration of a cannister and destruction of isoflurane in it has a higher or lower impact on overall greenhouse gas effect than the isoflurane it contains. (I get that the transportation and production of the cannister would come into the lifecycle impact also, but even just the cannister itself incinerated versus the isoflurane released to the outside air - there must be a figure on this somewhere surely?

Perhaps the answer is considered obvious, but it is not obvious one way or other to me.

RE: Low flow anaesthesia. Is it worth it?

Rob Loxley — Mon, 16 Feb 2026 17:21:00 GMT

[quote userid="10320" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248382#248382"]My understanding was that it's not the carbon in the isoflurane molecule, but that it's a potent greenhouse gas[/quote]

https://www.asahq.org/about-asa/governance-and-committees/asa-committees/environmental-sustainability/greening-the-operating-room/inhaled-anesthetics

RE: Low flow anaesthesia. Is it worth it?

Lucy Fleming — Mon, 16 Feb 2026 14:51:13 GMT

[quote userid="3169" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248368#248368"]I don't have figure in terms of CO2 (an isoflurane molecule has 3 carbon atoms in it, are we counting them?)[/quote]

My understanding was that it's not the carbon in the isoflurane molecule, but that it's a potent greenhouse gas (in the same way that methane is more potent than CO2). I don't know where it stacks up in terms of persistence in the atmosphere etc. As some others have mentioned, in terms of climate change I suspect it's very much tinkering on the very tiniest edge of all the edges compared to everything else...

[quote userid="2100" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248362#248362"]Chat gpt says there are around 2300 coal fired power stations in the world,[/quote]

Ironically, couldn't you have found the same information from a search engine (not google, admittedly, as it will just give you an AI answer anyway, but something like DuckDuckGo or Ecosia) using significantly less energy?

RE: Low flow anaesthesia. Is it worth it?

Evelyn Barbour-Hill — Thu, 12 Feb 2026 19:15:26 GMT

[quote userid="12930" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248373#248373"]Genuinely interestin in user feedback in my quest to unearth the best ga monitor![/quote]

The monitor is of course the nurse. The machines and devices are merely monitoring aids, and pointless unless they show something that the nurse cannot observe with five senses. Also pointless unless they reveal something that you can do something about.

[quote userid="3169" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248374#248374"] I hate pulse oximetry - it lies, tongue dries and we tolerate numbers not compatible with life, or the nurse spends more time messing with it than checking the patient. [/quote]

After using, struggling with, paying too much for and generally experiencing pulse oximeters, I concluded that they were of little use and not worth bothering with.

The single most important monitoring aid, the one that goes on absolutely every GA – for me – is the oesophageal stethoscope connected to an amplifier. Not very exciting: no numbers, no flashing lights, no bleeps, cheap.

RE: Low flow anaesthesia. Is it worth it?

Michael Woodhouse — Wed, 11 Feb 2026 22:46:38 GMT

[quote userid="12930" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248373#248373"]Genuinely interestin in user feedback in my quest to unearth the best ga monitor![/quote]

I feel most of the vet stuff is rebadged Chinese junk. If I bought a new one, I'd get one for £600 off ebay and replace when needed. My preference is 2nd hand human kit from ebay. Have a couple of these capnographs and they are tough, small and reliable

https://avantehs.com/p/bci-capnocheck-ii-hand-held-capnography-monitor/395

Only ever use the multiparameter on "big sick" - was a 2nd hand unit originally supplied by Vet Direct. A stand alone ex human continuous 3 lead ECG gives a much better trace. I hate pulse oximetry - it lies, tongue dries and we tolerate numbers not compatible with life, or the nurse spends more time messing with it than checking the patient.

RE: Low flow anaesthesia. Is it worth it?

Beats — Wed, 11 Feb 2026 21:31:46 GMT

I think a decent ga multiparameter monitor is a worthwhile investment for any clinic, even if only doing short ops.

My biggest problem is concluding what ga multiparameter monitor...

is that a mindray umec12 vet in the picture?

Does it beep incessantly, have an irritating touch screen, and require the alarm settings to be adjusted from unhelpful defaults every time it is turned on? Can it cope with HR below 60 without beeping?

Genuinely interestin in user feedback in my quest to unearth the best ga monitor!

RE: Low flow anaesthesia. Is it worth it?

Clive Ansell — Wed, 11 Feb 2026 11:56:40 GMT

[quote userid="2116" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248370#248370"]I'd be interested to see if the anaesthetic charges increase with the new equipment! [/quote]

I'll give you 3 guesses, but you'll likely only need one!

RE: Low flow anaesthesia. Is it worth it?

Clive Ansell — Wed, 11 Feb 2026 10:47:49 GMT

[quote userid="3169" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248368#248368"]By the time you've run a circle open for 10mins, shut everything down, you are opening it back up to wake up the bitch spay. Maybe of value with very long ops, but of minimal interest to me, and just adds complication. I feel similar about nitrous - in some ways I miss it, but it makes everything more complicated. [/quote]

Good point. Most routine procedures, and the bulk of our work, in first opinion practice are fairly short so have to wonder how much benefit and saving there would actually be? May well be very different in a referral practice where procedures are longer and more complicated?

Most of my cat procedures are very low or zero flow. Often use triple or quad combination injectable anaesthesia where no inhalation agent is required at all, just very low flow oxygen supplementation as and if needed.

Maybe a study needs to be done on affect of the choice of pre med and anaesthetic drugs on the environment? maybe choosing injectable rather than inhalation anaesthesia where possible could have a similar benefit??

I miss nitrous oxide too, but not seen it in practice for years now.

RE: Low flow anaesthesia. Is it worth it?

David Scarff — Wed, 11 Feb 2026 10:15:56 GMT

I'd be interested to see if the anaesthetic charges increase with the new equipment!

RE: Low flow anaesthesia. Is it worth it?

Michael Woodhouse — Tue, 10 Feb 2026 22:49:55 GMT

I'm calling cow poo on this one.

I don't have figure in terms of CO2 (an isoflurane molecule has 3 carbon atoms in it, are we counting them?), but we moved from cylinders transported around the countryside to oxygen concentrators, 12ish years ago. They produce a standard amount of oxygen when turned on/watt of electricity (may not be true of all but is of ours). Therefore there is no saving in electricity cost if we use less oxygen.

Isoflurane is cheap ~£25 for a 250ml bottle. We use capnography on all anaesthetics for safety, but I like to keep O2 flow as low as we safely can to reduce iso wastage.

We only use non-rebreating circuits, circles are more expensive, no messing about with soda lime (I worry about the dust), no need to close valves and run at very low concentrations (remember that 02 is consumed so really need anaesthetic gas monitoring for absolute safety). By the time you've run a circle open for 10mins, shut everything down, you are opening it back up to wake up the bitch spay. Maybe of value with very long ops, but of minimal interest to me, and just adds complication. I feel similar about nitrous - in some ways I miss it, but it makes everything more complicated.

I've had no dealings with the black magic Humphry etc circuits, the initial outlay puts me off. I costed them and a couple of circles with ongoing soda changes etc and for our level of operating, and usual duration, it made no sense - 10 years ago. My only reservation is that the student nurses we train have never experienced rebreathing or vaporiser in circuit circuits, but then I am training them for me, not everyone else.

If I was paying sevo money and using sevo vaporiser settings, I'll order some circles tomorrow.

RE: Low flow anaesthesia. Is it worth it?

Clive Ansell — Tue, 10 Feb 2026 18:43:36 GMT

[quote userid="2131" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248363#248363"]No, but it looks good in the publicity.[/quote]

Maybe you've hit the nail on the head!

They could now use use words and slogans like green, environmentally friendly, sustainability, protecting the planet etc. All totally meaningless and without foundation, but thats the way of it I guess

RE: Low flow anaesthesia. Is it worth it?

Clive Ansell — Tue, 10 Feb 2026 18:37:25 GMT

[quote userid="2100" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248362#248362"]What I am really trying to get at is whether you think 'low flow' has sufficient patient benefits. My understanding is that anaesthesia is pretty safe as it is, and there isnt any evidence that it improves survival.[/quote]

No, I don't think so. I have worked with most types of anaesthesia including so called low flow amd more efficient systems. I don't think any one system s better or safer than another, and I have not noticed improved recovery times or safety at all. As you rightly say, anaesthesia is very safe anyway.

[quote userid="2100" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248362#248362"]So if it costs to install all the new gear, is it really worth it?[/quote]

Difficult to see how, but would need to ask a practice owner really, the one actually paying the bills.

RE: Low flow anaesthesia. Is it worth it?

Evelyn Barbour-Hill — Tue, 10 Feb 2026 18:32:19 GMT

[quote userid="5012" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248361#248361"]If less oxygen and inhalation agents are used, it doesn't need a convention of rocket scientists to work out that it will reduce costs. has to be better for the environment too I would have though, by how much and how significant it is hard to say[/quote]

Having been genuinely low-flow for 42 years (fresh oxygen flow min 5ml/kg/minute, max 10ml/kg/minute; in-circle vaporiser,) I can confirm that there is a great saving in oxygen and in inhalation agent, and that the system is safe when correctly operated.

The exhaust goes through a charcoal absorber. No expensive special ehaust suction apparatus is needed. Whether this does "the environment" any good I have no idea.

I doubt whether super soaraway IVC have purchased a lot of in-circle vaporiser kit. I suspect that their "low flow" means "lower flow than we've been using before".

Not that I know of. But i'm not an anaesthesiologist. I do what I know is safe and effective. (Like most of us I suspect).

[quote userid="2100" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248362#248362"] 'improved patient care'.[/quote]

No, but it looks good in the publicity.

RE: Low flow anaesthesia. Is it worth it?

Arlo Guthrie — Tue, 10 Feb 2026 18:23:11 GMT

[quote userid="5012" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it/248361#248361"]has to be better for the environment too I would have though, by how much and how significant it is hard to say[/quote][quote userid="2100" url="~/f/clinical-questions/31308/low-flow-anaesthesia-is-it-worth-it"]I dug a little deeper and discovered that UK veterinary anaesthesia emissions are estimated at under 100,000 tonnes of CO₂ equivalent per year. A single medium-sized coal-fired power station emits several million tonnes annually. One plant. Millions.[/quote]

Chat gpt says there are around 2300 coal fired power stations in the world, roughly 800 of them medium-sized.

So the UK veterinary anaesthesia emissions are a fraction of a percent of power station emissions. As a percent of all emissions, gas power stations, cars, aircraft etc etc, its an incredibly small percentage.

So I think the idea that this is contributing to a reduction in emissions in any meaningful sense is probably wrong.

What I am really trying to get at is whether you think 'low flow' has sufficient patient benefits. My understanding is that anaesthesia is pretty safe as it is, and there isnt any evidence that it improves survival. So if it costs to install all the new gear, is it really worth it?

And this is not in any way to criticise IVC for having done so. I just think that with owners increasingly stretched, the value of everything needs to be questioned, rather than blindly going down the path of 'improved patient care'.

RE: Low flow anaesthesia. Is it worth it?

Clive Ansell — Tue, 10 Feb 2026 17:50:06 GMT

I cannot comment on costings, I don't own or manage a veterinary practice.

If less oxygen and inhalation agents are used, it doesn't need a convention of rocket scientists to work out that it will reduce costs. has to be better for the environment too I would have though, by how much and how significant it is hard to say

I am struggling to understand how it would deliver better and safer patient care, better recoveries and according to IVC "a higher standard of patient care"

As an aside, what difference is it likely to make to the environment when the US and its president, one of the largest and wealthiest countries in the world, denounces climate change as scam, and any measures to try and address it as a con. They want to continue burning fossil fuels at a phenomenal rate, so what difference will us pissing about with vet anaesthetics actually make in the scheme of things? square root of FA?? similar to all the BS with electric cars?

RE: Low flow anaesthesia. Is it worth it?

Rob Loxley — Tue, 10 Feb 2026 13:59:21 GMT

They've bought a pile of multiparameter monitors/ capnographs from what I can see. Maybe they've bought some mini-lacks and circle circuits where practices only had Bains or T-pieces? I think I'd agree with this being generally a wise spend, better monitoring for anaesthetics, maybe improves safety and patient outcomes I'm not sure the data is there?
The ability to easier run low oxygen flows (by monitoring CO2) is a biproduct and more PR/greenwashing, IMO.
There's probably a small saving in ongoing oxygen use and volatile agent use, as well as reduced emissions

RE: Low flow anaesthesia. Is it worth it?

Beats — Tue, 10 Feb 2026 11:44:10 GMT

My big issues are: 1) I have no idea what "low-flow" is supposed to mean. Do I do "low-flow"? I don't know. I would need some detail on precisely what is being proposed to know whether it is any different from what I have always done. 2) Could someone tell me if a charcoal adsorber is used whether this reduces isoflurane atmospheric concentration, and if so whether this is considered environmentally friendly or not these days? i.e. if we are "capturing" the isoflurane and then disposing of the cannisters (incineration??) presumably the isoflurane is not then released into the environment? I have never got a straight answer on this one, though I suspect an answer exists.