Pre-anaesthetic bloods - What are the statistics?

RE: Pre-anaesthetic bloods - What are the statistics?

Anthony Dennison — Thu, 16 Jan 2020 14:04:15 GMT

Dog was otherwise healthy and no clinical issues except cough and dry eye. I wouldn't have insisted on it, but if the client asked or expressed concerns over the GA I would offer it.

RE: Pre-anaesthetic bloods - What are the statistics?

KathW — Tue, 14 Jan 2020 17:25:02 GMT

Anthony, if this 13 year old dog hadn’t had pre op blood tests done, or if the pre op bloods has all been within normal limits, would you not have given Iv fluids? I advocate them routinely for older patients, partly to help maintain BP and renal perfusion.

I’m partly playing devils advocate to see if the pre op bloods actually changed anything in your GA protocol in this case as I think I would have suggested delaying the GA and investigating the raised SDMA first. Not saying there’s a right or wrong way, just adding to the debate.

RE: Pre-anaesthetic bloods - What are the statistics?

Anthony Dennison — Tue, 14 Jan 2020 15:20:52 GMT

Another one today - 13 year old Cocker in for bronchoscopy to investigate a chronic cough. SDMA of 21, ALKP 472, Urea 19. Urea likely due to fasting again, has been on maxitrol drops for dry eye long term. Raised SDMA didn't stop me going ahead (though I did use peri-operative fluids) but I have sent the dog back to the referring practice with a urine pot to further investigate it.

RE: Pre-anaesthetic bloods - What are the statistics?

Neil Wheadon — Wed, 08 Jan 2020 10:34:31 GMT

[quote userid="6297" url="~/001/veterinary-clinical/small-animal/anaesthesia/f/discussions/28772/pre-anaesthetic-bloods---what-are-the-statistics/218645"]What were the abnormalities you picked up on pre-op bloods?[/quote]

Hi George

I agree with this.

The standard ones I've seen are BUN, Creat, ALT, ALKP and Glucose

There is a larger CHEM 10 that's used but it's this 5 test that's the commenest by far

In my honest opinion, if these are normal it doesn't rule out a shunt

Neil

RE: Pre-anaesthetic bloods - What are the statistics?

Bob Russell — Wed, 08 Jan 2020 10:19:32 GMT

It is unlikely that the profile we run would have picked up much to suggest a shunt in what appeared to be a healthy dog.

That said a normal blood test would have been a minor comfort, normal or not!

RE: Pre-anaesthetic bloods - What are the statistics?

Thomas Johnson — Wed, 08 Jan 2020 09:26:31 GMT

[quote userid="2122" url="~/001/veterinary-clinical/small-animal/anaesthesia/f/discussions/28772/pre-anaesthetic-bloods---what-are-the-statistics/218640"]A good few years ago one of my excellent practice nurses and I toured the UK and hosted seminars to talk about the benefits of performing pre-op profiles, which we performed as a routine in the practice. When it came to doing her own puppy Border Terrier she was true to our message and had the bloods done for her pre-spey bitch - and had the devastating discovery that it had a liver shunt. Op cancelled, referral arranged to Langford, and they lived happily thereafter. We had other cases too where a clinical exam, and a decent history (including the referrals we got from west Wales) failed to highlight any problems - and the bloods did.[/quote]

What were the abnormalities you picked up on pre-op bloods? Most of the liver shunts I have seen have only had mild abnormalities apart from very elevated bile acids, which I have never seen included in a pre-op blood profile.

RE: Pre-anaesthetic bloods - What are the statistics?

George Cooper — Tue, 07 Jan 2020 23:50:10 GMT

And for that poor Bichon owner - the statistics are 100%.

A good few years ago one of my excellent practice nurses and I toured the UK and hosted seminars to talk about the benefits of performing pre-op profiles, which we performed as a routine in the practice. When it came to doing her own puppy Border Terrier she was true to our message and had the bloods done for her pre-spey bitch - and had the devastating discovery that it had a liver shunt. Op cancelled, referral arranged to Langford, and they lived happily thereafter. We had other cases too where a clinical exam, and a decent history (including the referrals we got from west Wales) failed to highlight any problems - and the bloods did.

RE: Pre-anaesthetic bloods - What are the statistics?

Bob Russell — Tue, 07 Jan 2020 14:28:12 GMT

We never 'sell' blood tests as a way of reducing anaesthetic risk. I do not believe they are that useful and 90%+ of the time this is mis selling.

We did have a Bichon that was incredibly slow recovering from routine anaesthetic and started to have seizure activity. Developed inhalation pneumonia (probably 2ary to the seizures not the anaesthetic). A complete disaster.

Turned out to have a shunt.

Not sure the pre-anaesthetic bloods would have guided us to that conclusion but I do wish we had done bloods anyway.

I am happy to use surgery as an opportunity to get baseline figures for the patient. Totally honest about the overall value of this sort of testing.

RE: Pre-anaesthetic bloods - What are the statistics?

Chris Geddes — Tue, 07 Jan 2020 14:13:34 GMT

Does this reinforce the point that bloods not necessarily unless indicated by history/clinical exam? If owner reported watery diarrhoea on admission, could have re-booked without the hassle/expense of bleeding and potential spreading of bugs around the practice? Strange that owner would not mention it, even without being specifically asked? Dehydration maybe not helped by owner perception that they need to withhold water as well as food prior to anaesthesia.

RE: Pre-anaesthetic bloods - What are the statistics?

Anthony Dennison — Tue, 07 Jan 2020 12:52:42 GMT

Interestingly enough, after this discussion - had an 18m old GSD in for spaying yesterday. PABs showed moderate azotaemia (crea 170, urea 20), SDMA normal. Dog then had really watery diarrhoea. Likely pre-renal and related to dehydration from fasting, so op postponed until diarrhoea resolved.

RE: Pre-anaesthetic bloods - What are the statistics?

Iain Richards — Sat, 04 Jan 2020 11:14:16 GMT

One of the things that strikes me about pre-anaesthetic bloods is that they are usually a pre-packaged bundle and are not that useful. SO which tests should be used if th eaim is truly to make the anaesthetic "safer". My list

Total haemaglobin, as that's the oxygen carrier. Albumin - most anaesthetics being protein bound. BUN and Crea. ALT and ALKP, but they have to be really wacky for me to be concerned. Maybe electrolytes,

NOthing replaces a good clinical exmaination and history

RE: Pre-anaesthetic bloods - What are the statistics?

Michael Woodhouse — Fri, 03 Jan 2020 20:36:23 GMT

Not recommended in people for most procedures:

https://www.nice.org.uk/guidance/ng45/chapter/Recommendations#table-1-minor-surgery

I will only ever advise them where there is something in the clinical history that gives me cause for concern. I very strongly believe it is unethical to push people into this kind of testing to 'make an anaesthetic safer'. Look at some of the work done - these cannot be easily justified when practising EBVM.

RE: Pre-anaesthetic bloods - What are the statistics?

Beats — Fri, 03 Jan 2020 19:10:06 GMT

[quote userid="8958" url="~/001/veterinary-clinical/small-animal/anaesthesia/f/discussions/28772/pre-anaesthetic-bloods---what-are-the-statistics/218526"]1) The risk is very very low[/quote]

It would be unreasonable to expect the effect on outcomes of anesthesia to be markedly altered by doing pre-anesthetic blood tests as any intervention aimed at increasing anesthetic safety is going to have very little impact given that anesthetic problems are incredibly rare to begin with [at least in dogs and cats].

[quote userid="8958" url="~/001/veterinary-clinical/small-animal/anaesthesia/f/discussions/28772/pre-anaesthetic-bloods---what-are-the-statistics/218526"]2) However if we are ever to get a baseline value, this is the time to do it as effectively killing two birds with one stone[/quote]

The same rationale can be applied to an echocardiogram, or abdominal ultrasound, or a Holter monitor, or a urine sample, or indeed a CT scan. It is a question of how many birds one wishes to kill. Then there is the issue of what "blood" tests one wishes? liver enzymes (which ones)? CRP? Bile acids? NT-proBNP? PT/APTT? Thromboelastography? The list is endless.

RE: Pre-anaesthetic bloods - What are the statistics?

Iain Richards — Fri, 03 Jan 2020 17:34:30 GMT

ALways remembering that outside a reference range is not necessarily abnormal or clinically significant.

RE: Pre-anaesthetic bloods - What are the statistics?

Neil Wheadon — Fri, 03 Jan 2020 17:23:57 GMT

Quite an impressive paper in my honest opinion

From Banfield

We reviewed data for a five-year period during which 992,892 anesthetic procedures were performed. Of these cases, 963,595 (97.1 percent) were screened (CBC, serum chemistry analysis, urinalysis), and 99.9 percent of those screened were found to be healthy and suitable for anesthesia. Most surgeries were performed on young Pets and overall screening compliance was virtually 100 percent, regardless of the size of the Pet at the time of surgery

My take home message for animals may well be twofold from this article

1) The risk is very very low

2) However if we are ever to get a baseline value, this is the time to do it as effectively killing two birds with one stone

Thanks for that, very interesting

Neil

RE: Pre-anaesthetic bloods - What are the statistics?

Anthony Dennison — Fri, 03 Jan 2020 15:22:19 GMT

We had a similar discussion at some point last year (or was it the year before?). I looked at one month of our ops, approx 200. Unexpected abnormalities were picked up in only about 5 or 6 of all these bloods. This was before we started running SDMA as standard however, there may be more now.

RE: Pre-anaesthetic bloods - What are the statistics?

Neil Wheadon — Fri, 03 Jan 2020 15:03:19 GMT

Can someone somewhere interrogate their PMS system?

Neil

RE: Pre-anaesthetic bloods - What are the statistics?

Beats — Fri, 03 Jan 2020 14:58:42 GMT

http://www.banfield.com/getmedia/1216c698-7da1-4899-81a3-24ab549b7a8c/2_1-Healthy-Pets-benefit-from-blood-work