Blood Pressure Measurement

dr. Annasia Mayasari

Once upon a time…..

Hales first measured blood pressure in 1733 by inserting tubes directly into the arteries of animals.

• Non-invasive techniques for the measurement of blood pressure have been in existence since the early 1800s, although Riva Rocci, an Italian physician, is credited with developing the first conventional sphygmomanometer in 1896.

• In 1905, Nicolai Korotkoff described various sounds while auscultating over the brachial artery during deflation of a Riva Rocci cuff.

BLOOD PRESSURE def • Blood Pressure is a measurement of the force against the walls of

the arteries as the heart pumps blood throughout the body

• Blood pressure is measured in mmHg (millimeters of mercury)

BP Variability

• The observer should be aware of the considerable variability that may occur in blood pressure from moment to moment with respiration, emotion, exercise, meals, tobacco, alcohol, temperature, bladder distension and pain, and that blood pressure is also influenced by age, race and diurnal variation, usually being lowest during sleep [16–19].

• Blood pressure measurement is the basis for the diagnosis, management, treatment, epidemiology and research of hypertension, and the decisions affecting these aspects of hypertension will be influenced for better or worse by the accuracy of the measurement.

• An accurate blood pressure reading is a prerequisite, therefore, regardless of which technique is used, yet all too often the accuracy of measurement is taken forgranted or ignored.

Blood Presure Measurement Method

Invasive Non- Invasive

non-invasive systems require three key components: • an inflatable cuff for occluding the arterial

supply to the distal limb; • a method for determining the point of systolic

and diastolic blood pressures • a method for measuring pressure • Others ( patient and observer)

Which machine??

• Every practice/ward should be using a validated manometer

• All manometers should be recalibrated and serviced annually

• Aneroid machines (not recommended) should be serviced more often as they deteriorate rapidly

Mismatching of bladder and arm

Bladder too small (undercuffing) Overestimation of BP • Range of error 3.2/2.4–12/8 mmHg (as much

as 30 mmHg in obesity) • More common than overcuffing Bladder too large (overcuffing) Underestimation of BP • Range of error 10–30 mmHg

Stethoscope • Good quality • Short tubing • Well fitting ear pieces (cleaned regularly) • Place gently over the brachial artery • Avoid touching the cuff and tubing. • The American Heart Association recommends using the

bell of the stethoscope over the brachial artery, rather than placing the diaphragm over the antecubital fossa, on the basis that the bell is most suited to the auscultation of low-pitched sounds, such as the Korotkoff sounds.

Which arm??

• 6% of hypertensives can have as much as a 10 mmHg difference between arms

• If BP higher in one arm than the other, this arm must be used from then on

• Document this in records so that everyone uses the same arm.

Body and Arm Position affect the result??

• Both systolic BP (SBP; by 9.5 +/- 9.0 (standard deviation, s.d.); right arm) and diastolic BP (DBP; by 4.8 +/- 6.0 mmHg; right arm) were significantly higher in the supine than in the sitting position.

• The forearm must also be at the level of the heart as denoted by the mid-sternal level.

Patient’s Body Position

• Routine - seated • Standing in patients with symptoms or

diabetic (diabetic nephropathy) and the elderly

• Supine position unnecessary, inconvenient and cuff position often below the heart.

Observer must do this…. (1) The observer should take care about positioning the manometer: • The manometer should be no further than 1 m away, so that the scale can be read easily. • The mercury column should be vertical (some models are designed with a tilt) and at eye level. This is achieved most effectively with standmounted models, which can be easily adjusted to suit the height of the observer. • The mercury manometer has a vertical scale and errors will occur unless the eye is kept close to the level of the meniscus. The aneroid scale is a composite of vertical and horizontal divisions and numbers, and must be viewed straight-on, with the eye on a line perpendicular to the centre of the face of the gauge.

Observer must do this…. (2)

• Give a warm greeting • Introduce your self • Educate and explain to pts about the

procedure • Observer should be in comfortable and

relaxed position • Do Not Rush and Crush

Graphical representation of cuff deflation, intensity of sounds on auscultation.

Matthew Ward, and Jeremy A Langton Contin Educ Anaesth Crit Care Pain 2007;7:122-126

© The Board of Management and Trustees of the British Journal of Anaesthesia [2007]. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org

If……

• We wish to re-measure BP deflate the cuff first