Postural hypotension and how to measure lying and standing blood pressure

A broader understanding of circulation and the circulatory system was developed in the early 1600’s by a doctor named William Harvey. He began teaching about circulation in 1615 and later published his work in 1628 entitled Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (On the Movement of the Heart and Blood in Animals). His work became a foundation for the study of the circulatory system, and is still highly regarded even to this day.

Interesting fact

In 1881, the first sphygmomanometer was invented by Austrian-Jewish physician Samuel Siegfried Karl Ritter von Basch. It consisted of a rubber bulb that was filled with water to restrict blood flow in the artery. The bulb was then connected to a mercury column, which would translate the pressure required to completely obscure the pulse into millimeters of mercury.

Interesting fact

Modern blood pressure measurement was not developed until 1905, when Dr. Nikolai Korotkoff, Russian vascular surgeon, discovered the difference between systolic and diastolic blood pressure. These pressures corresponded to the appearance and disappearance of sounds within the arteries as pressure was applied and then released. Known as Korotkoff sounds, the use of systolic and diastolic sounds is now standard in blood pressure measurement.

Interesting fact

Epidemiology

Definition of the Postural Hypotension

Orthostatic hypotension is more common in older people, and estimates of prevalence range from 5% to 30% of people aged over 65 years (in the general population), up to 60% of people with Parkinson's disease, and up to 70% of people living in care homes. It is estimated that about 0.2% of people aged over 75 years are admitted to hospital with problems relating to orthostatic hypotension.

The definition endorsed by the European Federation of Autonomic Societies is a sustained reduction of systolic blood pressure of at least 20 mmHg or diastolic blood pressure of 10 mmHg within 3 minutes of standing, or of tilting the body (with the head up) to at least a 60° angle on a tilt table.

Physiological causes:

Orthostatic hypotension

Chronic OH

• Baroreceptor receptor intensivity
• Diastolic dysfunction
• Hypertension

Autonomic failure

Pathological causes

Acute OH

Peripheral Nervous System

Central Nervous System

• Medication:
• alpha blockers
• antipsychotics
• antihypertensive and diuretics
• beta blockers
• bromocryptine
• levadopa

• Amyloidosis
• Alcohol
• Diabetes
• Pure autonomic failure
• Pernicious anemia
• Parancoplastic
• Tabes Dorsalis

• Brain stem lesions
• Lewy Body Dementia
• Multiple cerebral infarctions
• Multiple system atrophy
• Myelopathy
• Parkinsons Disease

• Sepsis
• Dehydration
• Diarrhea
• Vomiting
• Fever
• Heat
• Burns
• Adrenal Crisis
• Hemorrhage
• Myocardial Infarction
• Brady/tachy arrhythmia

Not all people with orthostatic hypotension experience symptoms. In addition, people who present with an injury or a fall may not be able to recall symptoms before the fall, meaning that the presence of orthostatic hypotension might be missed unless actively sought as part of a structured assessment. This is particularly the case in people aged over 65 years.

The symptoms of orthostatic hypotension include:

• dizziness
• light-headedness
• blurred vision
• fainting
• falling
• nausea
• fatigue

These symptoms usually go away as the body slowly adjusts to an upright position, or after sitting or lying down for several minutes.

Blood pressure monitoring: orthostatic hypotension will be diagnosed if there is a a drop of 20 millimeters of mercury (mm Hg) in systolic blood pressure or a drop of 10 mm Hg in diastolic blood pressure within two to five minutes of standing up, or if standing causes signs and symptoms.

Blood tests: these can provide information about overall health, including low blood sugar (hypoglycemia) or low red blood cell levels (anemia), both of which can cause low blood pressure.

Electrocardiogram (ECG or EKG): detects irregularities in the heart rhythm or heart structure, and problems with the supply of blood and oxygen to the heart muscle.

Stress test: performed while patient exercising, such as walking on a treadmill, or may be given medication to make heart work harder if patient is unable to exercise. When heart is working harder, it will be monitored with electrocardiography, echocardiography or other tests.

Tilt table test: evaluates how body reacts to changes in position. Patient will be placed on a flat table that tilts to raise the upper part of the body, which simulates the movement from a horizontal to standing position. Blood pressure measures will be taken frequently as the table is tilted.

Valsalva maneuver: checks the functioning of autonomic nervous system by analyzing heart rate and blood pressure after several cycles of a type of deep breathing as if patient were trying to blow up a stiff balloon.

The European Federation of Neurological Societies' guideline recommends individually tailored therapy for orthostatic hypertension and advises that goals of treatment are improving functional capacity and quality of life, and preventing injury, rather than achieving a target blood pressure.

Recommended management options are:

Patient education on orthostatic hypertension and advice on factors that influence blood pressure (for example, high environmental temperatures, sudden changes in posture, alcohol, and large, carbohydrate-rich meals).

Physical measures including raising the head of the bed, moving to upright gradually, leg crossing, bending or squatting, elastic stockings and abdominal compression bands.

Carefully controlled and individualised exercise training (swimming, aerobics, cycling and walking).

Blood pressure monitoring and management of raised blood pressure when lying down (supine hypertension), if needed.

Increased water and salt ingestion.

Pharmacological treatment, with fludrocortisone, midodrine. Other pharmacological options that may be considered include ephedrine, pyridostigmine and subcutaneous octreotide.

Instruct patients to:

• Be careful on awakening
• Elevate the head of the bed (reducing nocturia)
• Drink two cups of cold water 30 minutes before arising
• Shift from supine to an erect position in gradual stages.

Tell patients to take frequent, small meals and reduce alcohol intake.

• Hot drinks, hot foods, and meals rich in carbohydrates may be troublesome.
• Not take pressor medications after 6 PM
• Elevate the head of the bed to lower intracranial blood pressure
• Try a bedtime snack with a glass of warm fluid (to induce night time postprandial hypotension)
• Contract the muscles below waist for about half a minute at a time to raise blood pressure during prolonged standing or when feeling symptomatic.

Measurement of lying and standing blood pressure as part of a multi-factorial falls risk assessment.

1. Explain procedure to the patient.

2. The first BP should be taken after lying for at least five minutes.

3. The second BP should be taken after standing in the first minute

4. A third BP should be taken after standing for three minutes

5. This recording can be repeated if the BP is still falling

Identify if you are going to need assistance to stand the patient and simultaneously record a BP. Use a manual sphygmomanometer if possible and definitely if the automatic machine fails to record.

6. Symptoms of dizziness, light-headedness, pallor, visual disturbance, feelings of weakness and palpitations should be documented.

7. A positive result is:

a. A drop in systolic BP of 20mmHg or more (with or without symptoms)

b. A drop to below 90mmHg on standing even if the drop is less than 20mmHg (with or without symptoms)

c. A drop in diastolic BP of 10mmHg with symptoms (although clinically much less significant than a drop in systolic BP)

8. Advise patient of results and if the result is positive,

a. inform the medical and nursing team

b. take immediate actions to prevent falls and or unsteadiness.

9. In the instance of positive results, repeat regularly until resolved.

10. If symptoms change, repeat the test.

Note

Falls in older people: assessing risk and prevention says that the following groups of inpatients should be regarded as being at risk of falling in hospital and should receive an individualised, multifactorial assessment:

• all patients aged 65 and

• patients aged 50 to 64 years who are judged by a clinician to be at higher risk of falling because of an underlying condition.

Source: Royal College of Physicians

Measuring lying and standing blood pressure