Orthostatic Hypotension

Question 1

Define orthostatic hypotension

Answer 1

A drop of 20 mmhg systolic or 10 mmhg diastolic within 3 minutes of standing.

Check bp and hr at 1 and 3 mins of standing

IN HYPERTENSIVE PATIENTS A 30 mmhg limit is used

Question 2

What heart rate change should one anticipate if postural hypotension is due to rather than neurogenic

Answer 2

More than a 15 bpm increase

Question 3

Describe the normal physiological adaptation when standing?

Answer 3

700 ml of fluid shifts from thorax to lower limbs——decreased venous return and cardiac output—– activation of low and high pressure receptors—-central disinhibition of cns cv centres—— increased sympathetic and decreased parasympathetic tone—- partial restoration of stroke volume and increase hr and vascular resistance —- maintenance of mean blood pressure

Question 4

What physiological changes in the elderly make them more prone to oh?

Answer 4

1. Decreased baroreflex sensitivity
2. Diminishes heart rate response
3. Impaired alpha adrenergic vasoconstriction
4. Reduced parasympathetic tone leading to less cardio acceralation post vagal withdrawal
5. Aged kidney less ability to conserve salt
6. Reduced renin, ace and aldosterone activity with increased natriuresis reaponse
7. Non complaint diastolic impaired heart reduced stroke volume

Question 5

What are some of the non drug approaches to orthostatic hypotension?

Answer 5

Increase fluid and salt
Avoid getting up quickly
Use an abdominal binder or compressive waist high stockings
Raise head of bed 6-9 inches during night time
Avoid prolonged standing
Avoid exposure to hot environments
Cross legs while standing
Drink 450 ml of water as a bolus 
Maintain and exercise program