Blood pressure monitor?

Re: Blood pressure monitor?

Rajat — Tue, 22 May 2012 12:23:50 GMT

Not to flog a dead horse but found a paper I wanted to quote yesterday...haberman et all 2004...link here...lots of good info, conclusions are interesting and sway in favour of the doppler for cats. Full text available.

http://www.jarvm.com/articles/Vol2Iss4/BrownIJARVMVol2No4.pdf

Best

Raj

Re: Blood pressure monitor?

Rajat — Mon, 21 May 2012 12:29:37 GMT

I agree - dont take it at face value- read the papers, talk to specialists (anaesthetists, cardiologists, nephrologists) see costs and then decide. I probably should have said, in awake animals (esp cats), Oscillometric readings are often unreliable compared to doppler. Bearing in mind the caseload one has in Sa practice, cats and dogs+/- rabbits, awake and under GA, if there was one choice for a monitor, I know mine would be a good doppler, preferably with a smaller probe than the thames medical one e.g. huntleigh or parks. I find doppler to be quicker, more repeatable, gives more information and easier than an oscillometric unit. It is also more versatile (info on flow iunder GA) and more mobile in many cases (depending on your oscillometric machine).

As David alluded, it is important to remember the biases which may occur during hypo or hypertension with the device you have chosen. It is also interesting that none of the devices available on the market for veterinary use meet the criteria set for humans for Non invasive devices (see link for ACVIM consensus statement - http://onlinelibrary.wiley.com/doi/10.1111/j.1939-1676.2007.tb03005.x/pdf)

I enclose some papers here, and I have also done some informal inhouse trials where one measures BP with doppler and oscillometric (2 diff machines). While they are relatively consistent in animals under Ga I have had wild variations in conscious animal, and fitting with the general theme seen in resaearch papers, the variation is much greater in hypo or hypertension.Obviously the Doppler readings are also suscepotible to variation but I would always choose Doppler over oscillometric as you can hear the sound, and are not relying on the machine in these cases to come up with a number.

Agreement between directly measured blood pressure and pressures obtained with three veterinary-specific oscillometric units in cats.

J Am Vet Med Assoc. August 2010;237(4):402-6.

Comparison of high definition oscillometric and Doppler ultrasonic devices for measuring blood pressure in anaesthetised cats.

J Feline Med Surg. October 2010;12(10):731-7.

Comparison of ultrasonic Doppler flow monitor, oscillometric, and direct arterial blood pressure measurements in ill dogs.

J Vet Emerg Crit Care. April 2010;20(2):207-15.

Comparison of arterial blood pressure measurements and hypertension scores obtained by use of three indirect measurement devices in hospitalized dogs.

J Am Vet Med Assoc. April 2012;240(8):962-8.

Comparison of High Definition Oscillometric Blood Pressure Measuring Technique with Doppler Ultrasonic Device in Anaesthetised Cats

19th ECVIM-CA Congress, 2009

Indirect measurement of systemic blood pressure in conscious dogs in a clinical setting.

J Vet Med Sci. May 2008;70(5):449-53.

Best wishes

Raj

Re: Blood pressure monitor?

David Mills — Tue, 15 May 2012 23:16:24 GMT

[quote user="Rajat"]

Oscillometric readings are often non reliable,

[/quote]

I wouldn't take this at face value. Oscillometric actually performed better than Doppler in a prospective trial in terms of sensitivity and specificity trade off in awake dogs (when compared with arterial BP), with the point of greatest accuracy at around 150mmHg. Doppler is around 160mmHg.

The main influence is likely the operator with the Doppler being more fool proof but more fiddly especially in fractious animals. Also depends what you want it for - diagnosis or GA monitoring or both; in which case bear in mind the 'ideal pressures' above - receiver operator curve graphs in the paper mentioned show how the sensitivity/specificity trade off varies with pressure being measured.

http://www.ncbi.nlm.nih.gov/pubmed/12564729

In general, hopping between machines is inadvisable but each machine used correctly gives good repeatability for Doppler or Osc. One/other is not 'more accurate' inherently. Bear in mind that dogs' blood pressure varies between 10 and 20% each day anyway...

Re: Blood pressure monitor?

peewit — Tue, 15 May 2012 18:54:56 GMT

Parks every time.... so reliable and 'idiot' proof!

Re: Blood pressure monitor?

Rajat — Tue, 15 May 2012 18:08:09 GMT

hi Julian

As an all rounder you cannot beat a doppler unit. Oscillometric readings are often non reliable, better in the machines costing many thousands eg Cardell but still not as reliable and repeatable as a doppler. In addition, Doppler gives you soem info on blood flow (and an audible qualitative sound which is great under GA) which oscillometric cannot.

Cost wise Doppler is the most economical too, you could look at the Parks doppler or eickenmeyer do an almost identical unit which we bought to work alongside the Parks unit which are both in the £800 region. They pay for themselves very quickly and much easier to use more sensitive and much sturdier than the thames unit.

Cheers

Raj

Re: Blood pressure monitor?

Rob Loxley — Tue, 15 May 2012 18:04:57 GMT

[quote user="Julian Earl"]Our old BP monitor has gone kaput and I was looking for recommendations for a new one[/quote]

Why not see how much Thames want to repair your existing?

[quote user="Alet Engelbrecht"]the old brick shaped doppler (can't remember the name)[/quote]

Parks? They are the ones with replaceable probes on phono plugs.Somewhat more expensive though.

Other doppler options are the Vet Instrumentation one or the Huntleigh Vettex (similar to the Thames but much smaller probe, like the Parks)

Re: Blood pressure monitor?

Alet Engelbrecht — Tue, 15 May 2012 17:22:34 GMT

I looked into it a while ago for our practice - even trialed one of the fancy new oscillometric ones. In the end, we managed to repair our Thames medical one, although the old brick shaped doppler (can't remember the name), may be a bit cheaper to buy outright and very sturdy. We have a lot of older cats with kidney disease and various endocrine problems and got very erratic readings with the oscillometric that we needed to redo with doppler anyway. I actually asked a friend that was doing her anaesthesia residency and she also said they cannot go without doppler even in a sleeping animal.

So, in conclusion, I think doppler is still the way to go for the routine monitoring and I am only aware of those 2 on the market.