Blood Pressure Monitoring
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Collaboration Post #2
Blood Pressure Monitoring
By
Tammy Chamness
Tarleton State University
Companion Animal Diseases and Health Management
Blood Pressure Monitoring
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Monitoring blood pressure is a useful tool to ensure an animal under anesthesia is maintaining
proper cardiovascular functions or to help diagnosis possible cardiovascular issues. In order for
this monitoring to be useful, one must know the normal ranges for the species they are working
with.
Normal Arterial Blood Pressures
- Dogs: Systolic 140, Mean 100, Diastolic 75 mm Hg
- Cats: Systolic 180, Mean 135, Diastolic 100 mm Hg
- Horses: Systolic 110, Mean 90, Diastolic 70 mm Hg
(Dogs are subject to breed specific variations in blood pressure reference ranges)
There are two types of monitoring techniques, non-invasive method and invasive method, both
have their advantages and disadvantages.
Doppler flow detection in a non-invasive method which utilizes the metacarpal, metatarsal artery
or the base of the tail. Once a pulse is detected the doppler probe is positioned over the pulse and
secured in place. The proper sized cuff, ideally 40% circumference of the limb choose, is chosen
and placed proximal to the doppler probe and attached to a manometer. To ensure that the cuff is
neither too tight nor too loose, a small finger should be able to slide between the cuff and limb.
The cuff will then be inflated until the pulse is no longer audible on the doppler. It is then gently
released and a reading is taken when the pulse becomes audible again.
Blood Pressure Monitoring
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Advantages of this method is that it is cheap and available in most clinics. It is also useful in
hypotensive patients. The disadvantages include that it all measures systolic pressure and that it
is not useful in horses.
Oscillometric method is another noninvasive method requires a specialized oscillometric cuff to
be placed on a distal limb or tail. This cuff automatically inflates and as it deflates, oscillation in
the cuff is detected electronically. This method measures systolic, mean and diastolic pressures
Advantages to the oscillometer method are that it is automatic and works well in dogs.
Disadvantages are the expense and that it is less reliable in cats and hypotensive patients.
Arterial catheterization is an invasive method that requires the placement of a catheter into a
peripheral artery that is then attached to either an anaeroid manometer, which measures mean
arterial blood pressure, or an electronic transducer, which measures systolic, mean and diastolic
arterial blood pressure.
Advantages include continuous measurements and access for additional sampling for blood gas
analysis. Disadvantages are it being invasive and requiring correct equipment that can be
expensive.
Central venous pressure (CVP) is used to measure blood return to the heart, it indicates adequacy
of fluid therapy, heart performance and volume loading of the heart. This requires the placement
of a central line, usually placed in the jugular vein which is then attached to either an
anaeroid manometer or electronic transducer, just like in the arterial cauterizations method.
- Low or falling CVP suggest hypovolemia
Blood Pressure Monitoring
- High or rising CVP suggest volume overload or a failing heart
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Blood Pressure Monitoring
Reference:
WikiVet, 15 October 2013, https://en.wikivet.net/Blood_Pressure_Measurements
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