Pre-anaesthetic blood tests

Re: Pre-anaesthetic blood tests

Tim Newton — Mon, 09 Nov 2009 18:13:01 GMT

I entirely agree

Re: Pre-anaesthetic blood tests

beldather — Mon, 09 Nov 2009 16:44:47 GMT

[quote user="Tim Newton"]

In general I agree with you, when it comes to mapping out treatment that is an absolute requirement eg antibiotics with a cat bight abscess, frusemide with CHF, spay with pyo.

With fluids and bloods it is not so clear cut - it's risk vs benefit vs cost - and because the client bears the cost, they have to make the choice.

[/quote]

I think we all accept that for every case we usually have to compromise, I do think that everyone has a different opinion on what to compromise about. For instance while I refuse to knock out animals without an IV catheter, I probably would drop antibiotics from a cat bite abscess if cost was an issue (lance, flush and flush again).

Do I believe in PreA bloods, nope, although it is a pretty convenient time to get them done for those elderly guys. Give me a U/A and pcv/TP any day.
Will I refuse to knock out an animal if fluids arnt an option , Nope, but I will push pretty hard to have them included.

I do get really frustrated by practices I've worked in who push push push for PreA bloods, but would never consider using fluids. But I have to accept that we all have different ideas of what we as individual professionals feel the risk/benefit ratio is to our patients.

Regards

Blair

Re: Pre-anaesthetic blood tests

Evelyn Barbour-Hill — Mon, 09 Nov 2009 14:02:07 GMT

[quote user="Tim Newton"]

[quote user="Evelyn Barbour-Hill"]But, with respect, it seems to me that your approach is " doctor knows what is best for you, but you do what you like".[/quote]

Hi Eevelyn

No, I think you misread me. It is "this is the best option, this is what I recommend, but you choose".

[/quote]

Quite honestly, I can't see the difference.

But I don't want to get into a lengthy debate over it.

Re: Pre-anaesthetic blood tests

Tim Newton — Mon, 09 Nov 2009 10:01:46 GMT

[quote user="Evelyn Barbour-Hill"]But, with respect, it seems to me that your approach is " doctor knows what is best for you, but you do what you like".[/quote]

Hi Eevelyn

No, I think you misread me. It is "this is the best option, this is what I recommend, but you choose". In the same way we made our choice against medical advice when there was the MMR furrore, and our dear government made so much noise I thought it was an excercise in spin and was initially not going to have it done at all for our kids. We have anyway delayed the vaccination as we felt 4m is way too early. we waited until the age they start in mainland Europe. It was my choice and if one of my kids developed meningitis as a result of not being vaccinated, I would have to take responsibility.

Regards

Tim

Re: Pre-anaesthetic blood tests

Tim Newton — Mon, 09 Nov 2009 09:57:20 GMT

Hi Ian

In general I agree with you, when it comes to mapping out treatment that is an absolute requirement eg antibiotics with a cat bight abscess, frusemide with CHF, spay with pyo.

With fluids and bloods it is not so clear cut - it's risk vs benefit vs cost - and because the client bears the cost, they have to make the choice. I believe it is better to have an iv drip with anaesthesia and surgery, I believe pre GA bloods are advisable in old animals (and urine, BP in cats, etc, if poss), and I believe Hills/Iams/Royal Canin are better foods than a lot of the rubbish sold. But the client pays for it so the client chooses.

That is why in this situation we feel the preferred option is to inform clients and let them make their decision.

Regards

Tim

Re: Pre-anaesthetic blood tests

Hannah Wynne Richards — Mon, 09 Nov 2009 09:47:22 GMT

I'm with Ian on this one. Clients come to us for an expert professional opinion

Wynne

Re: Pre-anaesthetic blood tests

Ian Mostyn — Sun, 08 Nov 2009 23:04:57 GMT

Tim,

Your clients must be better educated than mine!! When I go to the garage for my car to be serviced I expect them to get it back to me working properly and safely. I don't expect them to ask me what oil I want or whether I want a new air filter, I leave that to their professional judgement because I trust them.... as long as the cost is reasonable and I can understand that oil is good for my car. My clients expect the same from me for their pets. They just want their pet back healthy and if that means i/v catheter's and fluids, they expect me to do what is needed (at a reasonable cost). Maybe this is just different parts of the country, different expectations after all I am a blunt Yorkshireman!!

Ian

Re: Pre-anaesthetic blood tests

Evelyn Barbour-Hill — Sun, 08 Nov 2009 22:11:45 GMT

[quote user="Tim Newton"]No, you see, I think that approach is in danger of being paternalistic The days of "doctor knows what is best for you, so do as I say" are gone,[/quote]

But, with respect, it seems to me that your approach is " doctor knows what is best for you, but you do what you like".

[quote user="Tim Newton"]We all have different approaches and beliefs.[/quote]

Yes. Something we should all remember now and then.

Re: Pre-anaesthetic blood tests

Lynne Faulconbridge — Sun, 08 Nov 2009 22:07:13 GMT

I have come across one animal that had a clinically inapparent juvenile nephropathy. She was a healthy active young Cocker spaniel who mwas not pupd and was fit and well on examination. PreGA bloods (CREA,BUN,GLU,ALP,ALT) showed markedly elevated CREA and BUN - she had small kidneys on ultrasonography and died of renal failure approximately 4 months later. The op she had come in for was a routine spay. The preGA meant that the animal was spared the surgery and given the best possible treatment for the rest of her sadly short life. It also meant that the renal failure was known not to have been triggered/exacerbated by the ga/surgery, which might have been a fair assumption if the preGA had not been carried out. So - I am a fan in of preGa and always give the owner the option, and keep the cost very reasonable. Perhaps we should be screening certain breeds, as has been suggested e.g. Dobies for VWD and spaniels (and other prone breeds) for renal disease?.

Re: Pre-anaesthetic blood tests

Evelyn Barbour-Hill — Sun, 08 Nov 2009 22:02:39 GMT

[quote user="Hanna Bennett"]The intraoperative fluids means that we have a bag in theatre opened each morning, and a drip line that is kept clean and capped between patients.[/quote]

I think we have been here before. We must agree to differ.

[quote user="Hanna Bennett"]but the bitches don't go that lovely grey colour as you tug on their ovaries, and are sat up and happy so quickly it's great.[/quote]

What grey colour? My bitches don't do anything like that. And of course it's great, but exactly how quickly are they sat up and happy?

Re: Pre-anaesthetic blood tests

Tim Newton — Sun, 08 Nov 2009 17:49:23 GMT

[quote user="Ian Mostyn"]If something is going to make a big difference to a patient then it should be pretty much compulsory / standard. How can an owner make a decision about whether fluids are going to be useful? Most can't, they just want what is best for their pet and should be able to judge your judgement. I like to think that my clients trust what I suggest and If I want bloods and fluids, fine, it is not an optional extra though like a car stereo upgrade.[/quote]

No, you see, I think that approach is in danger of being paternalistic The days of "doctor knows what is best for you, so do as I say" are gone, at least in my area, and a good thing, too. Our clients are educated and informed, and most of them are intelligent people. I do not allow my doctor to to dictate decisions to me about my health, and I do not do it to our clients, either.

Our job, as I see it, is to tell owners what the best options are, why we give them the advice we do, and let them decide. They make an informed decision, but the decision is theirs. You cannot force a client to let you do the lumpectomy, dental procedure, FNAB, cardiac ultrasound, you want to do, even though you think you know it is best for that patient. The same would apply to iv fluids, bloods, etc. Do you refuse to supply Felimazole if the client will not agree to a TT4, BUN, Creatinine every 3 months? We advise it, we tell them why it is important, if necessary we sometimes make a client sign a disclaimer, but if they refuse, they can still have the medication, as long as I see the patient every 6 months so I can stay on the right side of the regulations.

Yes, then sometimes that means I have to do a job in a way I think is not ideal eg a 15 year old dog having a dental with no iv line, or a cat on thyroid therapy where the owner will not do TT4 more than once a year. We even had one client who refused to allow us to monitor his diabetic cat once it was stable, and he was a GP!! But they know the dangers, the choice is the clients', and they have to accept the consequences.

We all have different approaches and beliefs. That is mine for what it is worth.

Regards to all, and I mean that.

Tim

Re: Pre-anaesthetic blood tests

Hanna Bennett — Sat, 07 Nov 2009 21:36:11 GMT

We have an option for 'intraoperative fluids' which is different from say an older cat with pre existing renal disease for a dental, which i would admit the night before and ensure good hydration prior to anaesthetic by having it on intravenous fluids overnight (likely just at maintenance rates before someone jumps down my throat for overhydrating cats!!!). That option is entirely based on my clinical judgement, and in that situation i would advise the client as i see fit. The other is one we offer as 'add on' to routine procedures. I guess we could just put every bitch spey on fluids but then we would have to put the prices up and some of our clients could not afford this so we would end up with more pyos which is not a good thing! We all know there are different standards of care/protocols applied by practices across the country - I've worked in practices where they did bitch speys under dom/ket/torb with no other analgesia, or with no premed at all, just thio induction and no analgesia at all - so yes, in an ideal world it would be gold standard across the board, but that is not how it works. We just figure that this way people can choose if they wish to spend the extra money or not, and my job is to advise them if i think it is a good idea - not had anyone request it for a castrate cat yet!

The intraoperative fluids means that we have a bag in theatre opened each morning, and a drip line that is kept clean and capped between patients. We put catheters in every patient that has an anaesthetic - which an awful lot of practices don't do either and that scares me! - so we just use a fresh T connector to hook each patient onto the fluids when they come through into theatre and run in fluids at anaesthetic rates using a drip pump (assuming no contraindications) during the ga,and they come off fluids when they come off the table. We have a nice piece of kit which you run the drip line through and warms the fluids pretty much at the point of entry, which we find helps massively to control peri-operative hypothermia. Maybe this is part of why they recover quickly rather than the fluids themselves, but the bitches don't go that lovely grey colour as you tug on their ovaries, and are sat up and happy so quickly it's great. Guess our analgesic protocol also comes into play, but have noticed a difference since using fluids this way.

Guess the other option is measure the bp and drip if it drops, but why wait til then?

Re: Pre-anaesthetic blood tests

Ian Mostyn — Sat, 07 Nov 2009 16:21:36 GMT

[quote user="Evelyn Barbour-Hill"]I don't understand this. If you think it's necessary shouldn't you just do it? If you don't think it's necessary why offer the option?[/quote]

I completely agree with you. If something is going to make a big difference to a patient then it should be pretty much compulsory / standard. How can an owner make a decision about whether fluids are going to be useful? Most can't, they just want what is best for their pet and should be able to judge your judgement. I like to think that my clients trust what I suggest and If I want bloods and fluids, fine, it is not an optional extra though like a car stereo upgrade.

Ian.

Re: Pre-anaesthetic blood tests

salome2001 — Fri, 06 Nov 2009 23:43:38 GMT

this goes back about 14 years so I'm sorry i don't remember more details. No recollection of anything amiss with the GA though. I seem to recall increased liver enzymes but I couldn't say. Probably did SBA to diagnose.

Re: Pre-anaesthetic blood tests

Evelyn Barbour-Hill — Fri, 06 Nov 2009 23:26:48 GMT

[quote user="Hanna Bennett"]we do not push fluids for every patient, but we include the option on our consent form.[/quote]

I don't understand this. If you think it's necessary shouldn't you just do it? If you don't think it's necessary why offer the option?

[quote user="Hanna Bennett"]bitch speys recover quicker when they've been on intravenous fluids during the op.[/quote]

What are the typical recovery times for with and without? I'm very happy with the rapid recovery of my bitch spays.

[quote user="Hanna Bennett"]All our ops are admitted and examined by a vet who goes through the consent form with the owner, which is the first practice i've worked in where they are not just handed over to the nurse by the client, and i think that is probably the singlemost important pre anaesthetic check![/quote]

I quite agree.

Re: Pre-anaesthetic blood tests

Hanna Bennett — Fri, 06 Nov 2009 21:24:20 GMT

just to clear up, we do not push fluids for every patient, but we include the option on our consent form. each case is discussed with the owners on its merits but boy do bitch speys recover quicker when they've been on intravenous fluids during the op. we also use drip pumps for every patient in order to prevent overhydration and our qualified VNs are more than capable of adjusting fluid rates as they or the vet sees fit dependant on any underlying diseases. All our ops are admitted and examined by a vet who goes through the consent form with the owner, which is the first practice i've worked in where they are not just handed over to the nurse by the client, and i think that is probably the singlemost important pre anaesthetic check!

Re: Pre-anaesthetic blood tests

Rob Loxley — Thu, 05 Nov 2009 17:05:49 GMT

Picking up on a previous link to the Association of Anaesthetists of Great Britain and Ireland, they state "Blanket routine pre-operative investigations are inefficient, expensive and unnecessary". They wouldn't get a job in some corporate practices; and what if the 2yo cat with an abscess to sedate and lance is insured, their boss would be fuming??!!

For hard and fast data on anaesthetic problems, David Broadbelt's thesis is very well worth reading (http://www.vetschools.co.uk/EpiVetNet/epidivision/brodbelt/Dave%20Brodbelt%20thesis.pdf), or the published papers based on it which are obviously more concise.
It did make some conclusions on animal outcomes based on ASA Status, which preop examination and lab work (and other investigations) may help determine, along with other risk factors. The increased risk associated with IV fluid therapy in cats is interesting, particularly if the suggested answer is just to put all animals on fluids, and selling that to the client as reducing risk...

I believe the best practice policy is not to have a practice policy: other than to do a full exam. Offer tests (be it blds, with/without T4, vWF testing, ECG, xray/echo etc.) as you feel appropriate, advise the owners on the pros and cons (what it might and might not show) and the costs, and let them make an informed decision. It's their animal and their money.

For your young, healthy animal, the likelihood of picking something up goes down, just on probabilities, but I guess if you test a large enough population you will find the odd, odd thing of significance. As for PSS, sometimes nothing shows on 'routine' bloods, you find out when they take hours to recover...
Consider vWF in appropriate breeds; again give the clients the info to make an informed choice.

However on another tack, why is it a bad thing to be proactive in our approach to medicine, particularly in older animals; why is it always referred to as 'defensive medicine' or 'avoiding getting sued'. We all know how common renal disease is in older animals and how a general anaesthetic can potentially worsen things, and that the owner may not report that the cat is PUPD or it may not have lost weight etc.

Why shouldn't we be looking for hyperthyroid cats before they present thin-as-rakes or with cardiac disease, and again we know the effects of hyperthyroidism on the cardiovascular system.

As for ECGs, my guess is that if you ran one on every healthy animal, you'd overall throw up many more questions than you answered.

Re: Pre-anaesthetic blood tests

Hanna Bennett — Wed, 04 Nov 2009 19:40:47 GMT

Again, the one in however many is the one that catches you out - 6 mo boxer bitch, lively, happy, poss a little thin but so many Boxers are at that age, in for spay. only one ovary/kidney at op, went into renal failure and was euthanased three weeks later.

Again i guess usg would have helped, but how do you get urine off a wappy boxer - bloods would have been the easier option in this case. Our pre ga bloods routinely include electrolytes and pcv too.

Having said that i don't routinely recommend bloods in young healthy animals, we encourage intra-operative fluids instead - all our anaesthetics have an iv catheter placed so this takes little extra effort. Recoveries are better for sure.

Re: Pre-anaesthetic blood tests

Tim Newton — Wed, 04 Nov 2009 08:17:12 GMT

I don't have papares, but two vet students doing work experience with me, one fomr RVC one form Canridge, and a part ime vet oding a PhD at RVC have all told me they are told in lectures that pre GA bloods, esp in young animals, have no effect on the complication rate.

We do as most of you seem to do - I mention the bloods option to owners, tell them they can have it if they want it, but advise them it is a waste of money IMHO. We encourage blood screening in older animals, then doing QBC, 12 strip biochem, and electrolytes, and also find significant oddities oftne enough to feel it worth while. we strongly encourage iv fluids across the board, have done for ten years, and are entirely convinced of the benefits to patients

Tim Newton

Re: Pre-anaesthetic blood tests

james hunt — Tue, 03 Nov 2009 23:29:07 GMT

Interesting anecdote salome2001, as you said could/would pre anaesthetic bloods have identified the PSS? - how was the shunt identified eventually? were there abnormalities evident on routine biochem following the anaesthetic episode?

Do you think other factors during the anaesthetic period (hypoxia/hypotension) played a role in the development of blindness in this case?

Re: Pre-anaesthetic blood tests

David Rudman — Tue, 03 Nov 2009 23:19:52 GMT

I wonder, why are you asking the question?
I don't think you can say pre-anaesthetic testing is a good or bad idea purely on the statistical likelihood of detecting abnormaliities that are clinically significant.

However I am afraid I don't know of any veterinary references that answer your question. I suspect the numbers involved in any studies would be quite small. I attended a session at BSAVA congres some years ago about the value of pre-anaesthetic blood testing and there was some human data presented that suggested that it was unlikely that pre-anaesthetic testing of healthy patients would detect anything that would alter a planned anaesthetic. I tried looking for you but couldn't find the reference unfortunately. But it is easy to find papers with references to pre-anaesthetic testing in human anaesthesia, where the numbers are greater e.g. http://www.aagbi.org/publications/guidelines/docs/preoperativeass01.pdf http://bja.oxfordjournals.org/cgi/content/abstract/74/3/250

It may be that pre-anaesthetic testing isn't statistically that useful, but I think prior to anaesthesia is a time when many people will focus on their animal's health, and screening a large number of animals will undoubtedly bring up some cases that will benefit from the results obtained e.g. young clinically normal animals with renal dysplasias that can have early treatment of renal failure as a consequence. If yours was the animal picked up then I'm sure you would feel grateful.

David

Re: Pre-anaesthetic blood tests

Alet Engelbrecht — Tue, 03 Nov 2009 21:08:05 GMT

I recently researched the issue myself, having been a locum in different practices and exposed to differing practice policies. I also don't value 'defensive medicine' and 'routine pre-anaesthetic bloods' much. I could not find much info with regard to veterinary medicine, but there are interesting documents in the human field.

Pre-anaesthetic blood tests are not and should never be considered as an alternative to good anaesthetic protocols - which include careful pre-anaesthetic assessment with identification of risk factors and careful patient monitoring during and after the procedure.

Risk factors for a 12yo cat would include renal insufficiency, hyperthyroidism and diabetes mellitus. We do not run Total T4 in house and this hypothetical example might be one that have renal parameters in the normal ranges because it is an early hyperthyroid. An animal with severe dental disease can have biochemistry values all over the place that must be interpreted with caution.

If we start practicing 'defensive medicine' we will never be able to run all the tests 'necessary' and actually do the procedure. Idexx is offering a non-interpreted 'senior wellness screen' for cats and dogs - it includes more than I would have in a basic vettest pre-ga screen, including Total T4 and a urinalysis - all for £15. The turnaround time is a couple of days (when there is not a postal strike!). When I see an older cat that needs a dental, I would often take the blood sample and cystocentesis during the consultation and book it in for about a week later - by which time I would know all the results. Most of the patients where we have found pre-existing problems, we already had a high index of suspicion for the problem.

As students in a 3rd world country, we were always told to narrow our tests down to what we suspected clinically. This is obviously has problems and I really enjoy being able to run a full biochemistry profile at an affordable price, but it has taught me a few valuable lessons - mainly that a test is not a substitute for a good clinical examination and minimum database.

Another thought: many practices have no policy on the use of IV catheters during an anaesthetic - I personally think that is a cheap and important safeguard. Should anything occurs in the peri-operative period, one has immediate iv access, valuable if the blood pressure is artificially lowered by the anaesthetic agents in a crisis situation.

Re: Pre-anaesthetic blood tests

salome2001 — Tue, 03 Nov 2009 20:26:35 GMT

one story from 17 years in clinical practice

Worked for an animal charity in Australia that rehomed a kitten and then got it back for its free spay at 6 months old. Clinically nothing apparent on exam: good bodyweight, heart and lungs all fine, abdo ok etc etc

Spay went fine.

On recovery cat was blind.

Turned out to have a PSS. Fixed at local university vet hospital but never regained vision.

Would pre-Ga's have identified it? Possibly. It was the one in a hundred that caught us out. Just a bummer if its your cat and you never got offered the blood test that might have saved its sight.

Re: Pre-anaesthetic blood tests

Jill Macdonald — Mon, 19 Oct 2009 14:43:35 GMT

Thanks!

Re: Pre-anaesthetic blood tests

james hunt — Fri, 16 Oct 2009 10:07:28 GMT

http://www.ava.eu.com/public/small-animal-public

some information and further references