Blood pressure measurement

Introduction

Introduce yourself to the patient with your name and role, and confirm the patients name and date of birth. Wash your hands. Explain the procedure, check the patient’s understanding and obtain consent.

Ensure that the patient is comfortable, check that they are not in any pain and ask which arm they would prefer to use for the procedure. Request the patient to adequately expose their arm by rolling up their sleeves or removing garments if necessary.

Warn the patient that, although the procedure should not be painful, it is normal for the cuff to feel uncomfortable or tight and that some people experience pins and needles in their hand. Let them know they can ask you to stop at any point.

If a patient’s sleeve is made of a thin material, in practice it is perfectly acceptable to take the blood pressure measurement over it, rather than asking them to remove their garment altogether.

Make sure the patient is not in need of the toilet as this can increase their blood pressure. The more comfortable your patient is, the less of a chance their blood pressure may be artificially raised (this is known as white coat hypertension).

Equipment

You will need to collect:

History

It is best practice to allow a patient a few minutes to sit still and relax before taking a reading to ensure accuracy, so it makes sense to fill this time with some relevant questions. In order to put any readings you obtain in to context you will need to know some basic information about your patient.

This would also be a good time to identify any ideas, concerns or expectations that the patient may have.

Past medical history

Ask the patient if they have known hypertension, and if they do, ask if they have a record of their readings at home for comparison. Identify which arm they usually take their readings from to ensure consistency.

Enquire about any other known medical conditions. There are multiple secondary causes of hypertension.

If there is a known diagnosis that could affect blood pressure, gently enquire about medication adherence. If the patient is non-adherent, then further treatment for hypertension may be unnecessary.

Primary hypertension is responsible for 95% of cases of hypertension. It is defined as a sustained blood pressure above 140/90 with no clearly identifiable cause (it is also known as ‘essential’ hypertension).



Secondary hypertension is responsible for 5% of cases of hypertension. It differs from primary hypertension in that it has an identifiable underlying cause. There are many causes of secondary hypertension.

Endocrine:

Cardiac:

Renal:

Other:

Social history

Include questions about alcohol, smoking and dietary fat and salt intake in your history. This provides helpful background information on potential risk factors. Recent stresses or a lack of sleep can also affect a person’s blood pressure. Pregnancy is another thing to bear in mind; blood pressure reduces in the second trimester, so a greater than normal result is abnormal, and could suggest gestational hypertension, or even pre-eclampsia.

The risk factors for essential hypertension can be divided into modifiable and non-modifiable.

Modifiable:

Non-modifiable:

Recent history

Ask the patient about their day leading up to their appointment to check for things that may have recently affected their blood pressure. Caffeine consumption and exercise can temporarily raise blood pressure, and should ideally be avoided before readings are taken.

Use this as an opportunity to put your patient at ease: “How did you get to the clinic today? Have you had a coffee this morning?”

Procedure

Ensure the patient’s preferred arm is placed comfortably at around heart level. Check that you are using the correct size cuff.

There are numerous different cuff sizes which may be used. The cuff bladder (the part which inflates) width should ideally be about 40% of the arm’s circumference.

Palpation

Palpate for the brachial pulse, medial to the biceps tendon. Line up the arrow marked on the cuff with the brachial artery and fasten the cuff around the patient’s arm.

Ensure that the valve is closed on the hand pump. Inflate the cuff whist palpating the radial pulse. At the point where you can no longer feel the pulse, read the meter; this is a rough estimate of the patient’s systolic blood pressure.

A primary estimate of systolic pressure helps to prevent tightening the cuff beyond what is necessary, as this is uncomfortable for the patient.

Auscultation

Deflate the cuff and close the valve again. Place the diaphragm of your stethoscope over the brachial pulse, just under the cuff.

Area of palpation and auscultation of the brachial artery.

Place the diaphragm just under the cuff.

Inflate the cuff to 20mmHg above your estimated systolic pressure. Next, by minimally opening the valve, slowly deflate at around 2-3mmHg/s, whilst watching the pressure dial.

Listen carefully for loud beating sounds called ‘Korotkoff sounds.’ When you first hear the sounds, read the meter; this will be the systolic pressure. You will continue to hear the sounds for a brief amount of time. Once the sounds have completely died away, read the meter again; this will be the diastolic pressure. Readings are usually taken to the nearest 2mmHg.

Systolic pressure is the maximal pressure in the aorta generated by the heart in ventricular systole. This is normally <120mmHg. Following systole, the pressure in the aorta will reduce, although it will be maintained at a high level by the elastic recoil of the aorta. The lowest aortic pressure, termed the diastolic pressure, will be present just before the next occurrence of ventricular systole.

Confirmation

If the reading is abnormal or different than expected, repeat the procedure to be sure of your result. Take the lowest reading and record this in the notes.

Ask the patient to try to avoid talking and movement to maximise the accuracy of the reading.

Explanation

In practise, you will then need to explain the result to the patient. It is likely you will also need to do this in an OSCE scenario.

If you haven’t already, look for past readings to compare against and check for reasons why the patients blood pressure might be high.

As with all explanations, it is best to establish what the patient already knows. This allows you to tailor your explanation to the correct level for the patient.

Blood pressure classification

Hypertension is defined as a blood pressure >140/90 – the level above which treatment has been shown to decrease progression and risk of disease.

The risk of cardiovascular events doubles for every 20/10mmHg rise in blood pressure.

Table defining the boundaries of prehypertension and hypertension.

Table defining the boundaries of prehypertension and hypertension.

Malignant hypertension

Once blood pressure reaches levels over 180/120, there is a real risk of organ damage, resulting in what is known as malignant hypertension. Delicate organs such as the eyes and kidneys are particularly vulnerable to the high pressure.


Damage in the eyes causes visual disturbances, whereas kidney damage presents with urinary signs such as haematuria. The brain can also be affected, leading to encephalitis, causing confusion and fits. Eventually congestive cardiac failure will develop due to the excessive strain of pumping against such high systematic pressure.

One non-invasive diagnostic test is fundoscopy. There are four signs of malignant hypertension that are identifiable on fundoscopy, corresponding to the four stages of hypertensive retinopathy. These are:

  1. 1. Silver wiring
  2. 2. Arteriovenous nicking
  3. 3. Flame haemorrhages
  4. 4. Papilloedema

Prognosis

If uncontrolled, hypertension can lead to an increased risk of:

A clear explanation of the patient’s diagnosis and prognosis is vital, as this will to improve the likelihood of compliance with their management plan.

Management

Hypertension can be managed both conservatively and medically.

Conservative management

There are a number of steps that can be taken before pharmaceutical intervention is required:

Medical management

In addition to the above it is also worth investigating to identify prognosis and possible causes. These can include an ECG/echocardiography, fundoscopy, a urine dip test and routine blood tests.

If a cause of secondary hypertension is identified, then this will be treated appropriately. Otherwise, it is assumed that the patient has primary hypertension, and this can be managed with the treatment algorithm recommended by the British Hypertension Society and NICE:

Treatment algorithm recommended by the British Hypertension Society and NICE.

Treatment algorithm recommended by the British Hypertension Society and NICE.

The goal of management is to keep blood pressure <140/90.

Treatment of hypertension can be a fine balance, as these medications can cause blood pressures to drop too low. It is important to safety net for this and to warn people about potential fainting and dizziness, especially in elderly people for whom falls are a very real threat.

A common OSCE scenario is a patient who has a cough due to the use of ACE inhibitors.







Summary of the above

  1. 1. Classify the level of hypertension and relay this to the patient.
  2. 2. Explain meaning, prognosis and potential complications to the patient.
  3. 3. Investigate to identify any cause(s) or the possibility of any end organ damage.
  4. 4. Manage the problem based on the cause, first conservatively and then medically or surgically if required.

Completion

Ensure the patient is comfortable and ask if they have any further questions. Thank the patient and wash your hands. Document your findings and note your treatment plan going forward.

List form

Instructions
When assessing each other, please click on each list item as you go along. Doing so will turn the list item green. Make careful note of any steps missed at the end.
We recommend completing any examination or procedure in under 10 minutes, but you can adjust the timer to suit your needs.
:

  1. Introduction: “Hello, I’m SimpleOSCE and I am a medical student. I need to take your blood pressure today. Can I confirm your name and DOB? Thank you.”
  2. Explain procedure and obtain consent: "This will involve me placing this device around your arm. It may get a little tight for a brief moment. Would that be okay?"
  3. Wash your hands.
  4. History (4-9)

  5. Explore any presenting complaints.
  6. Ask about past medical and family history.
  7. Ask about medication history and drug adherence.
  8. Ask about social history, particularly risk factors for hypertension.
  9. Enquire about exercise, smoking, alcohol consumption and dietary salt intake.
  10. Identify any ideas, concerns and expectations.
  11. Procedure (10-16)

  12. Ask the patient if they are comfortable and not in pain, and if they have an arm preference.
  13. Position an appropriate sized cuff on the patient’s arm.
  14. Palpate the brachial or radial pulse and inflate the cuff to estimate systolic pressure.
  15. Deflate the cuff and place the stethoscope by the brachial artery.
  16. Inflate the cuff to 20mmHg above the estimated systolic pressure.
  17. Deflate slowly until sounds are heard (systolic pressure), and they disappear (diastolic pressure).
  18. Repeat if required, otherwise remove the cuff and record your findings.
  19. Explanation and management (17-21)

  20. Discuss the meaning of your reading with the patient in order to keep them fully informed.
  21. Discuss conservative management where appropriate (salt intake, weight loss, exercise, smoking, alcohol, sleep and stress).
  22. Consider any investigations (ECG/echocardiography, fundoscopy, a urine dip test and routine blood tests) and offer them to the examiner if appropriate.
  23. Discuss medical management, considering any elicited side effects.
  24. Thank the patient and wash your hands.
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