1. Blood Pressure measurement
“The measurement of blood pressure is the clinical procedure of greatest importance that is performed in the sloppiest manner.”
Kaplan N. M. Amer J Hypertension 1998: 11: 134-6
Blood pressure is the single most important test that we do, if left untreated it causes strokes, heart attcaks and peripheral vascular disease.

2. The ‘silent killer’ Causes death from: Strokes Heart Attacks
Peripheral Vascular Disease
If untreated, leads to:
Renal failure, heart failure

3. Blood Pressure classification
Category Systolic BP Diastolic BP
Optimal < <80
High normal BP < <85
High normal BP
Grade 1 (mild)
Grade 2 (moderate)
Grade 3 (severe) ≥ ≥110
ISH (Grade 1) <90
ISH (Grade 2) ≥ <90
ISH = Isolated Systolic Hypertension

4. Thresholds for intervention
BP ≥ 220/120 mmHg: treat immediately
BP > /110/119 mmHg: confirm over 1-2 weeks, then treat
BP / mmHg: with CVD complications: confirm over 3-4 weeks, then treat
BP /90-99 mmHg: with CVD risk confirm over 12 weeks, then treat.

5. Blood pressure measurement sources of error
Errors due to manometer
Errors due to cuff
Errors due to the observer
Errors due to the patient.

6. 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
Useful website:-

7. Talk about different devices currently available.
Ref to BHS website for guidance re validated machines.

8. Manometers – electronic advantages
You can effortlessly take several readings
Meanwhile you can check pt records
Some ‘whitecoat’ effect can be detected
You can rely on the readings of other health care professionals.
(These advantages partly outweigh the disadvantage of the possible, slight inaccuracy of some devices).

9. Manometers – automatic disadvantages
Inadequate choice of cuff sizes
Large cuffs are long enough but too deep
Need for the equivalent of the ‘alternative adult cuff’ only available with the mercury manometer.

10. BP measurement Three or more readings, separated by 1 minute
Discard first reading and average last two
If large difference take further readings.

11. BP measurement -cuffs Cuff too small or too big
Normal cuff too small for 15% of patients
Cuff not level with the heart
Leaky rubber tubing or bladder*
Faulty inflation/deflation device*
* Applies to mercury manometers only.
Cuff too small BP over read. Cuff too big, BP over read. Last 2 bullet points apply to mercury manometers

12. Often too wide for ‘fat’ arms
Cuff sizes
Type
Size
Suitability
Adult
12cm by 23cm
for smaller arms
Alternative cuff
12cm by 36cm
will cover 95% arms
Large adult
15cm by 36cm
Often too wide for ‘fat’ arms
It is difficult to obtain an accurate BP in very overweight people as there are no appropriate cuffs available. To gain as accurate a BP as possible ensure that the centre of the bladder is over the brachial artery

13. 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.
All newly diagnosed hypertensives should have their BP measured in both arms, on one occasion only. !0% of patients will have a significant difference. The arm with the highest reading should be used from now on. This must be documented so that all health professionals use the same arm

14. Technique Patient seated and relaxed, not talking, legs uncrossed
Tight arm clothing removed
Correct cuff size
Arm supported with cuff horizontal with heart
Inform patient of discomfort and that several measurements will be taken
Mercury manometer on firm and level surface at eye level
Locate brachial or radial pulse.

15. Technique – cont’d Place stethoscope gently over brachial artery
Inflate mercury rapidly, 30 mmHg above occlusion of pulse
Deflate very slowly, 2 mmHg per second
Record first of regular sounds (systolic BP)
Record diastolic as disappearance of sound
Record measurements to the nearest 2 mmHg
Repeat twice more and average last two.
Place stethoscope gently over brachial pulse so as not to occlude sounds, especially in the elderly who often have quite prominent arteries

16. BP measurement - observer
Mercury column not level with the eyes
Failure to hear the Korotkoff sounds
Wrong diastolic endpoint (K4 or K5)
Subjective detection of Korotkoff sounds
Rapid cuff deflation
Single one off reading.
Subjective detection of sounds means that everyone hears sounds in a different way.

17. Gardiner – Hospital Doctor - 1993
Stethoscope
‘I have never managed to communicate to any patient, that there is really no point in trying to talk to me when I am using a stethoscope’.
Gardiner – Hospital Doctor

18. Stethoscope Good quality Short tubing
Well fitting ear pieces (cleaned regularly)
Place gently over the brachial artery
Avoid touching the cuff and tubing.
Short tubing gives a clearer sound as the sounds have less distance to travel it also gives a slight pull on ears which also gives a clearer sound

19. Posture 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.
Standing BP’s should be taken immediately on standing and 2 minutes after standing to evaluate spontaneous or drug induced postural falls in pressure. In most people, systolic blood pressure falls and diastolic pressure rises by a few mmHg on standing up. In older people significant drops of 20 mm Hg are more common. Diabetic nephropathy, a complication of diabetes, is when the kidney(s) become damaged and more protein than usual collects in the urine. As the disease progresses more of the kidney is destroyed. Over time the kidneys ability to function starts to decline which will lead to Chronic Renal Failure (CRF). Consequences are high protein levels in urine.

20. BP measurement - patient
Anxiety and unfamiliarity
Animated discussion about the latest news
Ambient temperature
Full bladder!
Postural hypotension
Difference between arms.

21. Patient Consent is taken as read when patient rolls up sleeve
Explain the procedure, that it may be a little uncomfortable and that several readings will be taken
Seated, relaxed, not speaking
Tight arm clothing removed
Arm supported (not hyper extended) with cuff level with the heart.
Even when the arm is hyper extended blood pressure readings will be higher

22. Explanation to the patient
Tell the patient their blood pressure reading
Write BP down – use co-operation cards
Give relevant leaflets/booklets on life style issues (not too many at a time)
Reassure patient that this is a risk factor not a disease (unless left untreated)
Do not lose to follow-up.

23. ‘White coat’ hypertension
Effective method of diagnosing a rise in blood pressure associated with having blood pressure measured
Maybe from anxiety
10-20% of subjects labelled ‘hypertensive’ may have ‘white coat’ effect.
Whitecoat hypertension is not innocent and pts tend to get lost to follow up. These pts may well become truly hypertensive over time. LVH present in ‘white-coaters’ but not to the same level as hypertensives. Any sign of LVH is a warning for urgent action

24. Ambulatory blood pressure measurement (ABPM)- indications
Borderline hypertension
White coat hypertension
Isolated systolic hypertension
Nocturnal blood pressure
Resistant hypertension
Hypotensive symptoms.

25. ABPM
Can be expensive
Should be comfortable for patient to wear (light and quiet)
Use of correct cuff size
Need to be familiar with equipment
Time to instruct patient, full explanation to patient of what is required
Requires patient co-operation in order to obtain as many readings as possible.

26. ABPM cont ….
Normal activity to be maintained, except when measurements are being made
Subject’s arm to be still during measurement
Subject’s usual activities to be carried out
Working days not compared to recreational days
For clinical use recordings are usually programmed for every 30 minutes during the day and hourly at night
Subject required to keep a diary of activities and symptoms.
Night time dippers = good prognosis, those that do not dip bad news. Black patients often do not dip.

27. Home monitoring Gives patients empowerment
May improve medication concordance
Device used must be validated
Multiple day time recordings, over 7 days (eliminating ‘white coat’ effect) with BP taken in the morning and evening
First 24 hour readings should be discarded
Home measurements usually lower than clinic readings.
Very little evidence, to date, that home monitoring predicts cardiovascular risk or outcomes more effectively than clinic readings. Wrist devices not recommended.