NSAIDS and General Anaesthesia

Re: NSAIDS and General Anaesthesia

David Mills — Mon, 16 Jul 2012 22:30:04 GMT

[quote user="Malcolm Ness"]

[quote user="David Mills"]This is convincing evidence to the contrary:[/quote]

No it isn't.

These are all either/or papers. As I pointed out previously, I am interested in anything that demonstrates a benefit to pre-op NSAID over post-op NSAID in cases that have been given pre-op opiates.

[/quote]

Not available in the veterinary literature. Plenty in the human stuff though showing that pre-op NSAIDs along with opiates show significant reduction in post op opiate requirements cf post-op nsaids.

As previously mentioned, the human stuff on this I regard as more sensitive indicators of analgesia due to inherent problems with any scheme for identifying, and quantifying pain, in animals (especially cats, but also dogs). Others might not but if we are to be EBM compliant then in the absence of anything to the contrary, I'll take a randomised double blinded prospective human trial over opinion, or anecdote.

Re: NSAIDS and General Anaesthesia

Malcolm Ness — Mon, 16 Jul 2012 21:50:43 GMT

[quote user="David Mills"]This is convincing evidence to the contrary:[/quote]

No it isn't.

These are all either/or papers. As I pointed out previously, I am interested in anything that demonstrates a benefit to pre-op NSAID over post-op NSAID in cases that have been given pre-op opiates.

Re: NSAIDS and General Anaesthesia

David Mills — Mon, 16 Jul 2012 13:40:19 GMT

[quote user="Malcolm Ness"]

Can you point me to the literature that supports this?

[/quote]

Largely due to experience in our clinic with early neuters.

There is some work in animals, e.g:

http://www.ncbi.nlm.nih.gov/pubmed/9845221

Although most of it is in humans, and is widespread:

http://www.ncbi.nlm.nih.gov/pubmed/12215691

http://www.ncbi.nlm.nih.gov/pubmed/11772800

http://www.ncbi.nlm.nih.gov/pubmed/8665876

etc.

It is arguable that because humans can articulate pain and pain pathways are very similar across dogs, cats and people, then this may be an area in which veterinary medicine is better to rely on human studies due to the inherent difficulties with defining pain in animals given behavioural abnormalities displayed during kennelling/clinic stays. Regardless, the human studies are overwhelming and show vast superiority of preoperative NSAID analgesia.

[quote user="Malcolm Ness"]

I don't recall anything that showed benefit of using pre-op NSAIDs WITH opiates.

[/quote]

This is convincing evidence to the contrary:

http://www.ncbi.nlm.nih.gov/pubmed/19305006

More so, NSAIDs have a slow onset until full effect (usu approx 2h)

http://www.ncbi.nlm.nih.gov/pubmed/8926722

which potentially leaves a window of pain if premed is a short-acting opiod and surgery is delayed.

And, as an aside, for those who regard NSAIDs with disdain cf opiods:

http://www.ncbi.nlm.nih.gov/pubmed/9762758

Re: NSAIDS and General Anaesthesia

Martin Atkinson — Mon, 16 Jul 2012 13:03:47 GMT

[quote user="Michael Woodhouse"]My bitch spays come trotting out wagging their tails, they are not in pain. Most people seem amazed how 'normal' their dogs are when going home.[/quote] My bitch spays also go home wagging their tails and they are given their NSAID as soon as I'm happy they have recovered from their surgery and there have been no complications. What has not been argued here is how much difference the surgeon makes. No disrespect to any here but If I can spay a cat in 5 minutes and a bitch in 15 and it takes a newly qualified assistant 4 times that long with a lot more tissue trauma, do their patients need more pain relief?

Re: NSAIDS and General Anaesthesia

Julian Earl — Sat, 14 Jul 2012 22:27:54 GMT

[quote user="Lorna McHardy"]

[quote user="Gillian Mostyn"]

[quote user="Julian Earl"]Anyway, I beg to differ on the effects of NSAIDs. I thinkwe observe noticeable visible improvements following their use. I can remember the days before they were routine when mammary strips, for example would come back post-operatively red and swollen, one would give them bute and two to three days later,hey presto, swelling and redness down, fever gone, comfort seen in the dog. [/quote]

And how do you know this wouldn't have settled with time anyway?

[/quote]

More than half of what we treat would settle with time anyway. I'd prefer it to settle faster, though, and with less accompanying pain or discomfort. Of course, I've no evidence for that, either....

[/quote]

What Lorna said. Also from knowledge about, and experience of, massively inflamed wounds with large amounts of exudative inflammation that are not swollen, not exuding, and the animal not pyrexic within forty eight hours of being started on NSAIDs. That is in comparison with those similar wounds that were treated with antibiotics ("the wound is obviouslyinfected") and which did not improve the same way. If only those wounds had received NSAIDs in advance.

Still I don't know that the sun will come up tomorrow...

Re: NSAIDS and General Anaesthesia

patrick murphy — Sat, 14 Jul 2012 15:58:59 GMT

any lectures that I have been on stressed the 'blocking' of inflamatory mediators released while we are playing with their tissues.

Re: NSAIDS and General Anaesthesia

Lorna McHardy — Sat, 14 Jul 2012 15:55:32 GMT

[quote user="Malcolm Ness"]

As always, I am not terribly interested in clinical anecdote other than as a starting point for clinical research. Its not that I am being disrespectful of the originator of the anecdote, merely mindful that for every strongly held opinion in one direction it is usually possible to find an equally strongly held conflicting opinion emanating from a clinician worthy of equal respect.

[/quote]

I know, and it's actually quite scary how many of the things we do, and are completely convinced are not only effective but safe, we have little or no real evidence for. For how many years, for instance, did the vast majority of us, fully convinced we were helping or at least not hindering, give large doses of corticosteroids to dogs with vestibular syndrome? Add to that the fact that when you do look at the research, it's not that uncommon to find it as contradictory as the opinions of clinicians. And of course, there's the vested interests to take into account when looking at drug company data... I still can't make up my mind about that new hyperT4 diet. They sound convincing. Eminent people endorse the stuff. But you don't have to look far for others who don't, for apparently excellent reasons.

But from my point of view - general practitioner trying to do my best but also with quite a few other things in my life - it's difficult. I simply haven't the time to read all the relevant papers and keep up to date with all the research unless I scrap the aforementioned other things; so I rely on a combination of CPD, general consensus, sites like this, specialists I speak to about cases, and other such sources to modify the things I've always done and believe to be effective because I've always found them so.

Maybe not ideal. But I think it's as it good as it gets for me on a practical day-to-day basis.

Re: NSAIDS and General Anaesthesia

Malcolm Ness — Sat, 14 Jul 2012 13:29:23 GMT

[quote user="Lorna McHardy"]More than half of what we treat would settle with time anyway. I'd prefer it to settle faster, though, and with less accompanying pain or discomfort. Of course, I've no evidence for that, either....[/quote]

Not disagreeing with that but it is not the points I was making re the dearth of evidence to show a measurable clinical benefit (not a perceived, believed or theorised advantage) to pre-op NSAIDs (as opposed to post op NSAIDs and not none at all). My recollection of Duncan Lascelles excellent work was that he demonstrated a benefit to pre op NSAID use similar to that seen with opiates. I don't recall anything that showed benefit of using pre-op NSAIDs WITH opiates.

Interesting to see mention of phentlybutazone above - still a useful drug but I wonder how much safer, how much more effective and how many exciting biochemical properties it would be found to have if it had a patent and a major pharmaceutical company to champion it!!

Re: NSAIDS and General Anaesthesia

Lorna McHardy — Sat, 14 Jul 2012 13:10:00 GMT

[quote user="Gillian Mostyn"]

And how do you know this wouldn't have settled with time anyway?

[/quote]

More than half of what we treat would settle with time anyway. I'd prefer it to settle faster, though, and with less accompanying pain or discomfort. Of course, I've no evidence for that, either....

Re: NSAIDS and General Anaesthesia

Gillian Mostyn — Sat, 14 Jul 2012 12:10:20 GMT

And how do you know this wouldn't have settled with time anyway?

Re: NSAIDS and General Anaesthesia

Julian Earl — Sat, 14 Jul 2012 09:50:59 GMT

[quote user="Malcolm Ness"]

Theoretical speculation is not evidence at all. Interesting that the NSAIDs have little, if any, measurable effect on the "obvious" signs of inflammation - heat, swelling, redness - but are reportedly matchless at dealing with the one we can't see - pain. Bear in mind that much of the information being bandied about in this debate was marshalled and presented to us by the drug companies - there's not many of us stay up to date with the source literature on pain.

Just playing devil's advocate.

[/quote]

I think there is independent research out there - Lascelles ahas published a few papers. However, although I'm not sure I think papers comparing carprofen and pethidene were probably company-related; likewise carprofen/meloxicam/opioids. It doesn't make the results completely useless.

Anyway, I beg to differ on the effects of NSAIDs. I thinkwe observe noticeable visible improvements following their use. I can remember the days before they were routine when mammary strips, for example would come back post-operatively red and swollen, one would give them bute and two to three days later,hey presto, swelling and redness down, fever gone, comfort seen in the dog. Ditto for a lot of injuries and procedures. Perhaps you are under-dosing?

Re: NSAIDS and General Anaesthesia

Malcolm Ness — Sat, 14 Jul 2012 08:50:54 GMT

[quote user="David Mills"]It is noticeable how less efficacious NSAIDs are post-surgery.[/quote]

Can you point me to the literature that supports this?

[quote user="David Mills"]It is the classic leap of faith from experimental (lowest grade evidence) to assumed clinical relevance.[/quote]

Just playing devil's advocate.

Re: NSAIDS and General Anaesthesia

David Mills — Fri, 13 Jul 2012 22:57:13 GMT

NSAIDs are vastly superior when given pre-emptively purely and simply because it is not possible to 'undo' the inflammatory mediators produced by COX-2(and COX-1/LOX). To think that opiods can prevent this is wrong - it merely prevents the animal from feeling it centrally, and does not prevent the cause. Therefore there is likely to be a 'gap' in the analgesia especially for routine surgery. It is noticeable how less efficacious NSAIDs are post-surgery.

I think the renal story about NSAIDs in a healthy animal is overplayed. There is fascinating evidence from old cats that does not show an increase in azotaemia when given meloxicam chronically, albeit at lower doses than 'full' doses. Unless the animal is too deep or the GA not well controlled then the reduction in renal perfusion that is significant as opposed to experimentally defined is minimal. It is the classic leap of faith from experimental (lowest grade evidence) to assumed clinical relevance.

As such, we give NSAIDs at admission.

Re: NSAIDS and General Anaesthesia

Michael Woodhouse — Fri, 13 Jul 2012 22:43:37 GMT

1. I think a lot of vets undervalue the pain killing properties of NSAIDS

2. I think the toxicity side is overplayed.

Young healthy animals I will give NSAID at pre-med or induction (usually just before knocking them out as have the dog sleepy). That way they have a little time to be absorbed before you start cutting. I use alpha 2 and butorphanol as a pre-med so the animal is actually getting three analgesics.

My bitch spays come trotting out wagging their tails, they are not in pain. Most people seem amazed how 'normal' their dogs are when going home.

Old and sickly things get fluids but not routine ops.

Re: NSAIDS and General Anaesthesia

Julian Earl — Fri, 13 Jul 2012 20:19:42 GMT

[quote user="Martin Atkinson"]

I agree with Malcolm on this also with the voice of experience. I give pre-op opiods with the pre-med and NSAIDs post op because you don't know how the surgery and recovery is going to go and NSAIDs in a potentially dehydrated animal with low blood pressure and consequent poor renal perfusion due to a prolonged recovery 'aint the best idea. The opiod is enough to prevent the pain cascade and the NSAID is to give longer term post-op relief. I say give pre/peri-op NSAIDs at your peril - you are playing on a sticky wicket. On another but not dissimilar note, I performed routine ocular surgery on a stable Addisonian patient today, it went on a saline drip but should we pre-emptively treat these with corticosteroids?

[/quote]

The pre-emptive pain relief applies to inflammatory pain as well so there should be benefit via that mechanism as well. The difficulty arises becaus eof inflammation being involved in the healing process and I am less concerned about dehydration/blood pressure than I am about effects of healing. The former can be dealt with via fluids etc., and then one has to take on board a certain amount that companies state as true, i.e. that the drug is okay to use at the time of a general anaesthetic. My second concern though, that of wound healing, is not something I have seen definitive work on. Personally, I suspect wounds heal more slowly but it may be only a marginal effect.

Re: NSAIDS and General Anaesthesia

Martin Atkinson — Fri, 13 Jul 2012 19:27:10 GMT

Re: NSAIDS and General Anaesthesia

Robin Grimmer — Wed, 11 Jul 2012 21:22:12 GMT

[quote user="Rajat"]

[quote user="Malcolm Ness"]I am familiar with the theoretical musings but when I last looked carefully, I couldn't find anything that convinced me that there was a benefit of giving pre-anaesthetic as opposed to immediate post anaesthetic NSAID in addition to a potent opiate.[/quote]

True, neither have I - however, while the musings may be theoretical, they do seem sound. NSAIDs seem to be equivalent in potency to control surgical pain compared to opioids (somewhat surprisingly) from the studies I can remember, but it'd be interesting to see if the combination is better than one alone -will have a look at the human pain book and report back if anything interesting crops up!

[/quote]

Isn't it better to give pre-emptive pain relief pre-surgery before all the pain receptors are stimulated?

Re: NSAIDS and General Anaesthesia

Rajat — Wed, 11 Jul 2012 19:33:56 GMT

Re: NSAIDS and General Anaesthesia

Malcolm Ness — Wed, 11 Jul 2012 19:27:15 GMT

[quote user="Rajat"]My understanding is utilising multi-modal analgesia and drugs with different mechanisms of action will have greater effects[/quote]

I am familiar with the theoretical musings but when I last looked carefully, I couldn't find anything that convinced me that there was a benefit of giving pre-anaesthetic as opposed to immediate post anaesthetic NSAID in addition to a potent opiate.

Re: NSAIDS and General Anaesthesia

Rajat — Wed, 11 Jul 2012 19:11:45 GMT

[quote user="Malcolm Ness"]This protocol comes form out review of the literature + experience that suggests that if potent opiate analgaesia is in place then there is no additional contemporaneous benefit to giving NSAID so we use NSAID to extend analgaesia beyond peri-operative opiate.[/quote]

My understanding is utilising multi-modal analgesia and drugs with different mechanisms of action will have greater effects - allowing lower doses of the individual drugs to be used. The more mechanisms of action of 'hypo'algesics (as pointed out these drugs are rather than a true 'an'algesic in this month's JSAP) that can be utilised, the better pain relief our patient's experience( is the current belief in the analgesia circles). IMHO, there are probably significant shortcomings in our assessment of patient pain, especially cats confounding the interpretation of benefit of one analgesic over the other.

Re: NSAIDS and General Anaesthesia

Malcolm Ness — Wed, 11 Jul 2012 18:29:06 GMT

We use methadone as a routine in (almost) every GA procedure. NSAIDs we give (again almost routinely) at time of tube removal. This protocol comes form out review of the literature + experience that suggests that if potent opiate analgaesia is in place then there is no additional contemporaneous benefit to giving NSAID so we use NSAID to extend analgaesia beyond peri-operative opiate. Reluctance to use pre-op NSAID relates partly o above and partly to a memory that goes far enough back to recall when pre-op Finadyne was "best practice" because it was "known" to be safe. Passage of time and accumulated experience indicates that we are probably being over-cautious but what we are doing seems to work and we are reluctant to change without demonstrable benefit.

Re: NSAIDS and General Anaesthesia

Rajat — Wed, 11 Jul 2012 18:01:20 GMT

[quote user="Mark Frost"] intra operative IVFT and BP measuring, the NSAID was given post op.. begging the question what were they afraid of? [/quote]

Agreed - if all is going well in a healthy animal why not give the NSAID?

Re: NSAIDS and General Anaesthesia

Mark Frost — Wed, 11 Jul 2012 17:57:50 GMT

Same as most, pre op with pre med in young healthy, then either 3 or 4 or none at all in an older/ill patient depending on the animal.

I worked as a locum in Australia last year and none of the practices I worked for gave NSAIDs pre op routinely, if any were given they were given post op.

(In one practice in a 6 month old cat spay that had pre op bloods, intra operative IVFT and BP measuring, the NSAID was given post op.. begging the question what were they afraid of? I asked, & the answer was, this was just what was done. Other questions were asked too.. although this is not the thread to discuss them!)

Re: NSAIDS and General Anaesthesia

Rajat — Wed, 11 Jul 2012 17:32:05 GMT

I only use NSAIDS preop in young healthy neuters/minor ops

For anything ASA III and higher or any geriatric or any 'ill' animal I reserve them for use (if at all) to the post op period if deemed appropriate.

IMHO, Local anaesthetic goes a long way to help reduce the need for NSAIDS in such cases. And ketamine CRIs!

Re: NSAIDS and General Anaesthesia

Robin Grimmer — Wed, 11 Jul 2012 16:58:24 GMT

pre-op with premed. If having pre-op bloods then wait until the results come through.

I'm a locum too and all the practices I work at generally follow the same protocol.

What about fluids though? This seems to vary quite widely between practices. I generally recommend fluids for all geriatric animals. One practice I worked at gave iv fluids for all bitch spays and even dog castrates.

I thought this was a bit OTT for a young, healthy dog castrate.