Preanesthetic testing

RE: Preanesthetic testing

Chris Milligan — Fri, 21 Jul 2017 18:12:55 GMT

I had an anaesthetist (human) bring his dog in for surgery a while ago and we debated the pros and cons of preanaesthetic testing. I've always thought the value of bloodwork is highly debatable before most elective surgeries - obviously it's done as a matter of course for a lot of more emergency or higher risk surgeries but that's mainly for the post-op anyway.

He was of the same opinion and said that in the human field they don't really care about it as the things that kill patients undergoing anaesthesia are aspiration, airway collapse and vascular accidents, not the stuff they check for in routine bloodwork. He declined preanaesthetic bloodwork by the way :D

RE: Preanesthetic testing

Wren — Fri, 21 Jul 2017 13:43:10 GMT

[quote user="Martin Atkinson"]When I had surgery on my fractured clavicle last year no pre-surgical bloods or urine were taken despite me being 66 just a swab for MRSA, BP and an ECG. Didn't bother me as I am very fit and healthy but you never know.[/quote]

I just got asked if I'd ever had MRSA or C. diff...

I'd say I've probably got 4 or 5 months' opportunity now before the op to drink myself into liver failure, or develop diabetes or kill off my kidneys. But my bloods will show a snapshot of me as I was yesterday. Which is, frankly, pointless.

RE: Preanesthetic testing

Martin Atkinson — Fri, 21 Jul 2017 11:26:35 GMT

[quote user="Alastair Franklin"]While the documented event was inexcusable, negligent and unprofessional, [/quote]I wouldn't even say that, he just was not being a very good vet.

[quote user="Alastair Franklin"]...recommended further work up and treatment that was declined by the owner, [/quote]This should have been his saving grace he may have been unsure enough of the validity of his previous investigation to question it - lymphoma is the great pretender. A very strong case for a review unless he was a habitual offender.

[quote user="Braden Collins"]I wonder what would have happened had the vet not done a pre-anaesthetic blood test. Would they have still faced a complaint when the cat subsequently died[/quote]This just serves to illustrate that you're likely damned if you do and damned if you don't.

[quote user="Wren"]I am due to have an eye op, under sedation, not GA. Date as yet unknown, but expected to be several months hence. I was required to submit both blood and urine samples for pre-op testing, despite being relatively young, pretty healthy and having absolutely no intercurrent disease or history of any medical issues whatsoever.

What, exactly, is the point of pre-op bloods taken several months before the op?

[/quote]When I had surgery on my fractured clavicle last year no pre-surgical bloods or urine were taken despite me being 66 just a swab for MRSA, BP and an ECG. Didn't bother me as I am very fit and healthy but you never know.

RE: Preanesthetic testing

Wren — Fri, 21 Jul 2017 09:25:43 GMT

Well, going back to the NHS comparisons, I had a pre-op assessment yesterday.

I am due to have an eye op, under sedation, not GA. Date as yet unknown, but expected to be several months hence. I was required to submit both blood and urine samples for pre-op testing, despite being relatively young, pretty healthy and having absolutely no intercurrent disease or history of any medical issues whatsoever.

What, exactly, is the point of pre-op bloods taken several months before the op? Unless someone can provide me with a sensible explanation I am going to file this one under 'waste of NHS resources'.

RE: Preanesthetic testing

Iain Richards — Tue, 20 Jun 2017 21:49:35 GMT

I'm sure those with better knowledge will comment, but only those incidents that are tested at the DC hearing can be considered when DC makes its judgement. Previous offences will, if relevant, be presented.

RE: Preanesthetic testing

vetbl.locum — Tue, 20 Jun 2017 18:00:18 GMT

When you read or hear about these incidents , it is often said that others factors were involved hence the punishment.

However these factors are rarely disclosed

I for one would like to see the RCVS be more open about their reasons for the punishment given

Rgss

RE: Preanesthetic testing

Braden Collins — Tue, 20 Jun 2017 08:02:31 GMT

I agree it's a pretty severe punishment, but I guess there may have been other factors which were not included in the newsletter.

I wonder what would have happened had the vet not done a pre-anaesthetic blood test. Would they have still faced a complaint when the cat subsequently died (the owner may have blamed the anaesthetic/procedure), or would it have been a case that was never followed up. I wonder if they still push for pre-anaesthetic bloods.

RE: Preanesthetic testing

Alastair Franklin — Tue, 20 Jun 2017 03:58:05 GMT

[quote user="Braden Collins"]• sit the examinations for membership with the Australian

& New Zealand College of Veterinary Scientists (Small
Animal Medicine or Small Animal Surgery) within two years
of the order.[/quote]

Interesting that they state 'sit' the exam rather than 'pass'. I think they would be far better served by insisting on appropriate CPD.

While the documented event was inexcusable, negligent and unprofessional, the suspension is arguably quite a severe punishment given he evidently (after the initial event) recommended further work up and treatment that was declined by the owner, especially in comparison to other punishments doled out by vet boards (perhaps WA are trying not to be the toothless tiger)?

RE: Preanesthetic testing

Gillian Mostyn — Thu, 15 Jun 2017 14:22:36 GMT

Thanks - very useful.

RE: Preanesthetic testing

Braden Collins — Thu, 15 Jun 2017 14:19:25 GMT

A story from the most recent newsletter from our Registering body in Western Australia which I think is worth sharing:

Ms K presented her cat, Buffy to Dr P at ACME Veterinary Clinic
due to his inappetence. Dr P advised her that the cat had a
“rotten tooth as well as an abdominal blockage…” and he
“recommended removing the tooth as well as a 5-day course
of laxatives.”
Five days later, Buffy was admitted for surgery to remove the
rotten tooth. Ms K consented to, and signed off on, a preanaesthetic
screening blood test. The screening pre-anaesthetic
blood profile was taken which demonstrated a significant
elevation in total bilirubin of 97 umol/L (Normal range 0-15
umol/L). Dr P wrote in his clinical record that a:
“Pre-Anaesthetic blood profile was taken and run – please see
attached for blood results. Note all within normal limits, except
bilirubin which was elevated. Given liver and kidneys were
OK…we proceeded with an uneventful anaesthesia …”
The cat recovered uneventfully from the surgery.
Two days later, Ms K presented Buffy to Dr P as the cat
had deteriorated, was not eating and was lethargic. Dr
P recommended that the cat be hospitalised, placed on
intravenous fluids and that further tests be undertaken, which
Ms K declined.
Buffy was subsequently treated at two other practices. The
cat died five days later following a blood transfusion at an
emergency veterinary hospital where further tests indicated that
the cat was likely to have lymphoma.
The Board referred the matter to the State Administrative
Tribunal where it was agreed at mediation that Dr P had
behaved unprofessionally by recommending to Ms K that
a pre-anaesthetic blood profile be performed but failing to
have regard to the results and failing to discuss the results with
Ms K before anaesthetising Buffy. Further Dr P failed to consider
whether in light of Buffy’s history, the unknown cause of the
elevated bilirubin and the non life threatening nature of Buffy’s
dental condition whether it was appropriate or necessary to
administer anaesthesia to Buffy and perform the non-emergency
dental procedure.
It was ordered that Dr P:
• pay a fine of $1,000.00;
• pay the Board’s costs of $5,000.00;
• have his registration as a veterinary surgeon suspended for
four weeks; and
• sit the examinations for membership with the Australian
& New Zealand College of Veterinary Scientists (Small
Animal Medicine or Small Animal Surgery) within two years
of the order.
DISCUSSION
Veterinary surgeons recommending to clients that their animal
has a pre-anaesthetic blood screening profile appears to be an
increasing trend. Opinions in the veterinary profession vary as
to the value of performing routine blood screening tests prior to
giving an anaesthetic and it is unlikely that a unified profession
wide opinion on this can be agreed.
However, if a veterinary surgeon recommends and performs
pre-anaesthetic blood tests, then the results of that testing
MUST guide whether they proceed with the anaesthetic or not.

RE: Preanesthetic testing

Beats — Mon, 05 Jun 2017 20:03:46 GMT

[quote user="Iain Richards"].1% "abnormal" results. By abnormal they mean out of their reference ranges. [/quote]

By "abnormal" they mean beyond a pre-defined cut-off that *may* alter a decision to anesthetise a pet.

"Abnormal" in this context did not mean outside the reference interval defined as the values beween which 95% of healthy patients are expected to fall.

See figure 2 and e.g. the platelet counts or wbc counts as recognisable ones to UK eyes (and figure 2 footnote).

RE: Preanesthetic testing

Iain Richards — Mon, 05 Jun 2017 19:43:06 GMT

I was sent these links by a kind member of the forum:

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

About a million pets showing less than .1% "abnormal" results. By abnormal they mean out of their reference ranges.

http://skeptvet.com/Blog/2015/02/what-you-know-that-aint-necessarily-so-pre-anesthetic-bloodwork-in-dogs-cats/

A review similar to mine

RE: Preanesthetic testing

Beats — Mon, 05 Jun 2017 19:40:11 GMT

[quote user="Kate Richardson"]Renal enzymes[/quote]

I know what you mean, Kate, but I think this is an example of where it is less confusing to just state the tests I suspect you are referring to, e.g. creatinine/urea (neither of which is an enzyme I think?)

I think sometimes we talk about tests such as "urine test" or "blood test" or "physical exam" and we might all be thinking of slightly different things. "Full profile" came up earlier in the thread. The nursing sample paper had a multiple choice asking which of the following was NOT part of a pre-anesthetic blood test (or words to that effects) - I sighed.

RE: Preanesthetic testing

Kate Richardson — Sun, 04 Jun 2017 22:43:32 GMT

Maybe we should stop calling them pre-anaesthetic bloods and just call them a health screen or pre surgical screen or something else. And I think we should think more about what we are testing for, rather than a standard mini biochem and cbc. Haematocrit and protein levels are important. Electrolytes important. Think of those occasional Addisonian dogs that don't recover as expected. Renal enzymes- more post op complications than intra- op. Liver enzymes- if the animal is eating drinking peeing and pooing normally and isn't losing weight, how likely is it that they have hepatic dysfunction? Do I really need a dynamic bile acids to tell me that all is ok to proceed and does this make things safer for the animal? Blood clotting- now that's surely a very important factor with regards to surgical safety but how many of us are routinely checking coag times?

Have been thinking about this a lot while this thread has been going- there is almost more requirement in some ways to run a pre op health screen or pre surgical screen for a non urgent 'routine' procedure in an apparently healthy animal than there is for a necessary surgery. I don't advise them in a young healthy animal coming in for neutering, but in some ways I think maybe these are the cases where we should- we are performing an elective procedure- we don't expect any problems. However these are the ones that when things go wrong, we feel really bad about. Could we have prevented it? I suspect not, and I'm not convinced that running a pre-op blood test would change the end result, but what if it did in one? Probably not on the table so to speak, but what about the occasional young animal with sub clinical renal disease, blood pressure drops during surgery due to some haemorrhage or just because it does, iv fluids not routinely used during GA or BP not monitored, animal recovers fine, goes home, with NSAIDs for pain relief and presents in renal failure a few days later. Would I feel bad- yes I would. Could I have prevented it? Yes quite possibly. Would I have done things differently- yes - I would have insisted on iv fluids or cancelled the procedure or I might have gone ahead with the owner now knowing there might be an outcome other than all good and they accepted that risk for an elective procedure.

The story however is very different if we are talking about a non or less elective procedure (obviously all surgical procedures are elective to one degree or another) but say a mass removal or a dental procedure.

So for example, I do a lot of dental procedures in older animals, and I discuss bloods but more in a 'let's check general health, make sure there's not something more serious going on that means that an anaesthetic may not be the priority right now' kind of way. Particularly if there are other symptoms that explain the weight loss for example. But if I see an animal with dental pain, and I feel that that is the animal's biggest concern right now, then my priority is to fix that pain. So my line is that, this animal needs a dental treatment, we can run bloods to assess general health, but the bottom line is it needs this procedure, and I am happy to proceed to an anaesthetic without blood work if necessary (usually costs, sometimes animals temperament). Do I change my GA protocol- not really- I monitor BP and use IV fluids to effect in most cases as I assume a degree of renal disease, bloods don't change that. I use bloods more to rule out more serious disease, or to assess for concurrent problems than to make the anaesthetic safer. Or to pre treat the animal, ie start iv fluids the day before.

So ultimately, I think you have to think about each case and how it might affect your management of that particular case and have that discussion with the owner and advise appropriately, but not just advise bloods regardless or because you've been told to. At least that's how I work!

RE: Preanesthetic testing

Nicola Cole — Fri, 02 Jun 2017 21:32:31 GMT

[quote user="Anthony Todd"]

[Arlo, delete anything I post if you believe it is turbotic]

Aren't we all approaching this argument from the wrong end?

Of anaesthetic incidents or deaths in healthy animals, [or clinically normal, for the pedants], how many, if any, would, or could, have been predicted, by PABs?

In addition the fact of normal PAB would, in the mind of most owners, raise more questions as to cause?

[/quote]

I don't routinely offer pre-anaesthetic bloods on apparently healthy animals. There is a bit on the consent form which asks about them and I usually say-in an animal of this age with no apparent clinical problems (on exam or history) bloods are highly unlikely to give us any information (or words to that effect) that would alter an anaesthetic.

If I have identified a case where I think it would be a good idea ie. I'm concerned about their general health, then I will say that in that case I think bloods should be done and not really leave it up to the owner-as far as I'm concerned it's my decision to make and advise upon. Middle aged cats would be the main ones that come into that category-owners are often poor at picking up changes in drinking habits unless very obvious....

Anecdotal: the only anaesthetic death in an otherwise apparently healthy animal I've had over the past 12 years was a young cat castrate on recovery-pre op bloods would not have prevented it (touching wood now...).

RE: Preanesthetic testing

Arlo Guthrie — Fri, 02 Jun 2017 17:38:59 GMT

At the suggestion of a member, I've deleted some of the posts in this thread and edited others (where they referred to deleted posts). I think it's an important discussion, and hopefully you'll agree that the meat remains. Just removed a bit of gristle.

Glen McIntosh, David Mills will be unable to reply for a week.

RE: Preanesthetic testing

Anthony Todd — Thu, 01 Jun 2017 23:29:43 GMT

[Arlo, delete anything I post if you believe it is turbotic]

Aren't we all approaching this argument from the wrong end?

Of anaesthetic incidents or deaths in healthy animals, [or clinically normal, for the pedants], how many, if any, would, or could, have been predicted, by PABs?

In addition the fact of normal PAB would, in the mind of most owners, raise more questions as to cause?

RE: Preanesthetic testing

Gillian Mostyn — Thu, 01 Jun 2017 22:24:33 GMT

[quote user="Iain Richards"]However, in the real world that is worried owners who do not want their animal to be the 1 in 1,000 (because their pet is 1 in 1,000,000) there is little wrong in them paying for the tests - as long as the vet has explained that the test is unlikely to make any difference and will not make the anaesthesia safer.[/quote]

I wonder how many vets, offering PABs in young animals for small procedures, describe them this way. None in my experience. (I was encouraged to offer them in a previous job, primarily to increase revenue.)

RE: Preanesthetic testing

David Mills — Thu, 01 Jun 2017 21:44:57 GMT

[quote user="Glen McIntosh"]. If your entire argument regarding the ethicality of PABs rests on the claim that PABs in APPARENTLY healthy animals MAY create a very minor negative welfare experience that doesn't actually cause the animal to suffer, then it is pretty weak.[/quote]

It wasn't. Although an interesting point is that if vets are all running around doing PABs on healthy animals the total negative welfare effects will be high. As I said this isn't the worst thing we do to animals in the pursuit of veterinary medicine. But that is not to say it is "weak" - it's still unethical. And you conveniently strawmanned the argument to ignore the professional ethics side of things.

[quote user="Glen McIntosh"](although I suspect that even the most pompous and supercilious faculty members would be tut-tutting and somewhat embarrassed by your response to George's post)[/quote]

Sassy. Do you not see the irony of your ad hominem attack? Calm down dear.

[quote user="Glen McIntosh"]but I don't think it will hold a lot of water for most veterinary surgeons. [/quote]

Bandwagon fallacy / no true Scotsman fallacy. Have you asked them? Hoew do you explain away the support for my arguments on here?

[quote user="Glen McIntosh"]But some of it, especially in human medicine, relates to cost control for health insurance purposes (be it private health insurance companies or nationalised heath insurance schemes such as the NHS). This is also important, since it assists in allocating scarce resources to where they will do the most good for the most peopl[/quote]

This is oft-quoted but actually there is very little evidence for it. If it was true, the NHS wouldn't perform transplants, heart surgery or fracture repairs. This is opinion being pesented as fact and it is somewhat tiresome.

[quote user="Glen McIntosh"]But as others have said, it is a numbers game, and for the individual, rarely, running (or not running) PABs may have life changing consequences.[/quote]

This has been covered. /it is exploitation and such wild "life changing consequences" rhetoric is unhelpful.

[quote user="Glen McIntosh"]Despite this, most medical anaesthetists request pre-anaesthetic blood screening in patients, depending on their preference, as well as electrocardiography, thoracic radiography and even spirometry in young healthy adults (Silverstein & Boland 1994; Tarnow 1996; Thöns & Zenz 1997; Larsen 1999; Morgan et al. 2006[/quote]

So what? This is irrational, irrepsonsible, and unethical. And also an appeal to authority logical fallacy.

[quote user="Glen McIntosh"]George W Bush had a coronary artery stent placed a few years ago. This caused a lot of controversy in human[/quote]

/oh goody more anecdote. /it has no bearing on the argument.

[quote user="Glen McIntosh"]Interestingly many cardiologists said that they would have done exactly the same thing in GWB's situation themselves, despite the evidence and despite the fact that they cannot recommend or justify the same to their patients (esp insured patients).[/quote]

Getting repetitive. Just bcause someone in authority does something it doesn't make it justifiable, right, ethical, or best practice. See above. The mind boggles that you're using this as a defence. [quote user="Glen McIntosh"]This is also my experience for veterinary specialists (including veterinary anaesthesiologists), who really should be aware of the evidence, but none the less routinely order pre anaesthetic bloods prior to any anaesthetic procedure for any animal, even apparently otherwise healthy young animals.[/quote]

See above. It really doesn'tmatter what specialists do. It remains unethical even if lots of people do it.

[quote user="Glen McIntosh"]Personally I do OFFER PABs (a full haematology, biochemistry and electrolytes - [/quote]

Despite all the evidencewe have showing they're useless and possibly damaging?? I honestly give up. And "offer" is a get out.

I really did expect better from the profession. Ho hum.

RE: Preanesthetic testing

Neil Wheadon — Thu, 01 Jun 2017 17:53:29 GMT

From a friend who's a very experienced consultant Anaesthetist.

Interesting I've just been teaching preoperative assessment to some MSc students.

Reasons for any test:

1. baseline: because there's a chance you may start a medication or treatment that may impact on, say, renal or liver function. We quite often use drugs that require liver function test checks after a week of use so do LFTs routinely before cardiac surgery.

2. because the test will help understand risk and inform discussion with patients: in cardiac, renal function is a variable in the Euroscore (risk score), so needs to be known to allow informed consent

3. because there is a reasonable chance that you will find something abnormal, which would potentially impact on the outcome AND which you would seek to correct/ameliorate prior to surgery. e.g. low haemoglobin: if very low, it could signify GI pathology that might need treatment prior to heart surgery or mean that heart surgery became too risky (e.g. bleeding oesophageal varicies or Ca bowel with widespread mets); if mildly low, we check iron levels and if low treat with intravenous iron and erythropoetin.

4. serological testing if blood transfusion may be needed.

Generally, for day case surgery we don't do any testing. In fact the evidence for any testing is extremely small even for moderate to large procedures. If people have a reasonable cardiovascular function and no history of other diseases, one just goes ahead. In the 1970s in the US everyone listed for a GA had a chest x-ray. Dr Miller did a study which showed that it took over a million x-rays before an anaesthetic plan was changed. That was the end of routine x-rays and he went on to become Prof Miller.

RE: Preanesthetic testing

Iain Richards — Thu, 01 Jun 2017 11:22:34 GMT

So, after a morning on the search engines, I have a contribution. Caveat - this is not a complete review, so I'm happy for any corrections.

GA Mortality risk

CEPSAF (Brodbelt et al 2008) risk of mortality within 48hr 0.17% Dog (n = 98k) 0.24% Cat (n = 79k). Healthy - 0.05% Dog, 0.11% Cat. Sick 1.3% Dog 1.4% Cat (interesting similarity).

French Practice study n = 3546 1.35% mortality by recovery (sternal) >ASA 3 mortality 4.77%

Effect of pre-op biochemistry - 3 human studies (there are more, these were recent) all showing very little influence of routine testing on changes to management. 1 study of 500 folk aged 40 - 70 suggested blood glucose as routine and renal function in patients >70.

It's quite clear that in healthy animals (ASA score 1 or 2) pre-operative blood workup will make very little difference to your anaesthetic regime. If you are not going to change your regime (eg giving a smaller induction dose of propofol in a hypoalbuminaemic animal) anyway, then testing really is immaterial. If you've categorised the patient as ASA 3 or greater then the justification for testing is there. I also found another human paper looking at overall health screening with similar results for ECG, XR, ultrasound in healthy patients - no difference.

There are complicating factors for us. How reliable are in-house analysers (especially in healthy animals) what are their positive and negative predicitve values for each test? How many of our pateints get a full clinical examination prior to anestheisa? How many of our patients are monitored by adequately trained staff? Given we are using the same drugs as humans the differences in mortality (0.01 - 0.02%) could well relate to a better understanding of anaesthesia. I'd suggest the unexplained death mid-op is more likely to be related to operator error/no monitoring (like capnography) than a missed pre-existing condition. Fluids have been mentioned as a potential complicating factor (I didn't look at this, but overload is easy to do).

Where does this fit in the debate? I feel there is no substitute for a thorough clinical examination and history prior to an anaesthetic/sedation prodecure. Learning the ASA scores and applying them is vital. Any testing can then be based on these findings. In the score 1-2 group, testing is of minimal impact. However, in the real world that is worried owners who do not want their animal to be the 1 in 1,000 (because their pet is 1 in 1,000,000) there is little wrong in them paying for the tests - as long as the vet has explained that the test is unlikely to make any difference and will not make the anaesthesia safer.

Time for a brew....

RE: Preanesthetic testing

Anthony Todd — Wed, 31 May 2017 19:28:21 GMT

[quote user="Iain Richards"]POB are NOT able to make anaesthetics safer and should not be offered as such, all they can do is highlight a potential complicating factor in an individual.[/quote]

Everyone seems to be dodging the obvious question which is "so what?"

Almost all anaesthetics are needed for some serious reason.

If you had a nut case that needed a GA to have the nails cut, but had serious liver problems then of course not, but nearly all, if not all, animals have to have a GA to fix some serous or painful problem which cannot be left.

In my experience these animals sail through GAs, so, even though their bloods show disease, does it affect their anaesthetic resilience?

Surprisingly, not in my experience, but then this doesn't count anymore.......

RE: Preanesthetic testing

Iain Richards — Wed, 31 May 2017 09:43:46 GMT

As anaestheisa is a bit of a thing for me, I'll trawl the literature and report back. However, previous posters have it right - POB are NOT able to make anaesthetics safer and should not be offered as such, all they can do is highlight a potential complicating factor in an individual.

However, to many owners, that individual is their all and I agree with George's view.

RE: Preanesthetic testing

Glen McIntosh — Wed, 31 May 2017 04:26:13 GMT

[quote user="David Mills"]And, before anyone says it, the fact we do other things that are worse is not the point. We are talking specifically about pointless PABs in healthy animals.[/quote]

I'm going to say it anyway. If your entire argument regarding the ethicality of PABs rests on the claim that PABs in APPARENTLY healthy animals MAY create a very minor negative welfare experience that doesn't actually cause the animal to suffer, then it is pretty weak. Especially given that the PABs under discussion are, predominantly, being performed prior to procedures that aren't medically necessary for the immediate health of the animal, procedures that will cause the animal tangible (albeit minor and short term) suffering but are deemed (quite correctly in my opinion) to be an overall net positive for both individual and global animal welfare (i.e. neuter surgery).

Your argument might win a formal debate at a philosophy department in one of the ancient universities (although I suspect that even the most pompous and supercilious faculty members would be tut-tutting and somewhat embarrassed by your response to George's post) but I don't think it will hold a lot of water for most veterinary surgeons.

EBVM is a good thing. Human EBM is also a good thing. Especially when it helps to identify and correct dogma that, at best, does not improve outcomes, or at worst, causes actual harm. But some of it, especially in human medicine, relates to cost control for health insurance purposes (be it private health insurance companies or nationalised heath insurance schemes such as the NHS). This is also important, since it assists in allocating scarce resources to where they will do the most good for the most people. It is in this context that the studies (both human and veterinary) regarding PABs should be viewed. Clearly no vet or doctor should be saying that running PABs will definitely reduce or eliminate anaesthetic risk when viewed from a global perspective. But as others have said, it is a numbers game, and for the individual, rarely, running (or not running) PABs may have life changing consequences.

An interesting quote from the veterinary paper regarding PABs cited earlier in the thread:

Alef, M. Oechtering, G. (2008) Is routine pre-anaesthetic haematological and biochemical screening justified in dogs? Veterinary Anaesthesia and Analgesia. 35(2), pp.132-140

"Several studies of medical anaesthetic practice fail to support the case for routine pre-anaesthetic haematological and biochemical testing in the absence of abnormalities revealed in the medical history or physical examination...Despite this, most medical anaesthetists request pre-anaesthetic blood screening in patients, depending on their preference, as well as electrocardiography, thoracic radiography and even spirometry in young healthy adults (Silverstein & Boland 1994; Tarnow 1996; Thöns & Zenz 1997; Larsen 1999; Morgan et al. 2006)."

George W Bush had a coronary artery stent placed a few years ago. This caused a lot of controversy in human cardiologist circles at the time, because this broke all the EBM rules. He had not had a heart attack. Indeed he had no symptoms of heart disease whatsoever. He had taken a screening test that EBM studies had deemed to be causing overall harm rather than benefit because of potential risks associated with invasive tests that follow from positive findings on initial screening. He subsequently had those invasive tests and some lesions were found. He subsequently had stents placed despite best available EBM studies that showed that stenting of lesions with the same degree of severity as those occurring in Bush's coronary artery did not reduce overall risk of death from heart attack compared with doing nothing (or conservative treatment such as diet, exercise).

Interestingly many cardiologists said that they would have done exactly the same thing in GWB's situation themselves, despite the evidence and despite the fact that they cannot recommend or justify the same to their patients (esp insured patients).

This is also my experience for veterinary specialists (including veterinary anaesthesiologists), who really should be aware of the evidence, but none the less routinely order pre anaesthetic bloods prior to any anaesthetic procedure for any animal, even apparently otherwise healthy young animals.

In the veterinary medicine context, I would view the available evidence regarding PABs as a clear justification for charities not to perform PABs as a routine for otherwise healthy animals, and for insurance companies to refuse to pay for these in healthy young animals.

I don't view this evidence, however, as justification for labelling private veterinary practices or veterinarians that do OFFER PABs as an option for routine procedures in young apparently healthy animals as unethical, provided that fear mongering and false claims regarding their clinical usefulness are not made. Similarly I can't see any particular ethical issue for practices that package bloods as part of the whole surgical/anaesthetic cost as George has advocated. In my view decisions regarding PABs for routine procedures in young apparently healthy animals (that have had a full clinical exam and history collection with no evidence of disease) become a matter of consumer choice, and therefore a business decision for individual practices and the veterinarians working within them as to whether they are offered routinely.

Personally I do OFFER PABs (a full haematology, biochemistry and electrolytes - i don't see much point in the abbreviated "pre anaesthetic" packages) to owners of otherwise apparently heathy young animals having relatively minor procedures under GA (e.g. caesarians, superficial wound repairs etc) in almost all cases (this is in the context of emergency practice, I haven't worked in GP practice for over 10 years, but I would probably do the same in that context). But I advise the owner that I do not consider them essential and that I am happy to proceed without them. If they have further queries I advise them that if I thought they were clinically necessary then I would tell them that, and would have unequivocally ADVISED or RECOMMENDED them, but I don't, so i haven't, but equally there is no real downside to doing them except cost. If the owner has financial concerns then I advise the owner not to do them, and save the money for something else. Most people decline them, fine by me, but I will make a note in the clinical record that bloods were offered and declined..

I am not sure, though, that I would be comfortable working in a practice where I felt my performance was being assessed by PAB sales. I probably wouldn't do very well.

RE: Preanesthetic testing

Gillian Mostyn — Tue, 30 May 2017 22:20:20 GMT

George did admit that clients, on hearing that their pet needs an anaesthetic, immediately assume it will die. That, oddly, certainly seems to be true. He therefore uses pre-an bloods to reassure them, all the while knowing that they have almost zero chance of actually preventing anaesthetic morbidity or mortality (despite his and others anecdotal reports to the contrary. We should be using evidence, not stories.)

That makes me mad as hell too!!!!

p.s. I'm interested how many pre-an blood screens, commonly carried out in-house, would pick up a non-symptomatic hepatic shunt. I know ours (rarely used) doesn't include bile acids.