Postural hypotension

Definition of Postural hypotension
This is another simple but very confuse topic. Because different people has different definition. I try to look through most of the standard text book but it seems quite confusing too. Please place your comment here and let us discuss what is the most correct definition we should follow.

Systolic Blood pressure -SBP
Diastolic Blood pressure -DBP

Oxford handbook: drop of SBP or DBP > 15mmHg at 3 minutes of standing.

Kumar and clerk and Davidson: drop of SBP > 20mmHg or DBP > 10mmHg. -- (no duration mention).

Nicholas Talley: SBP > 15mmHg or DBP >10mmHg. -- (no duration mention)

Mc Cleoid: SBP >20mmHg. ( no duration or DBP mention)

Hutchinson: SBP >30mmHg. ( no duration or DBP mention)

Shastry : SBP >20mmHg or DBP >10 mmHg 2 minutues after standing.

Harrison : SBP >20mmHg or DBP >10mmHg within 3 minutes of standing.

Joint National Commitee (JNC 7)(US) :SBP > 10mmHg

What do you think?? should we check standing BP immediately after standing? at 2 minutes? at 3 minutes? or after 3 minutes? How about the SBP and DBP??

The most accepted definition of postural hypotension is "a systolic blood pressure decrease of at least 20 mm Hg or a diastolic blood pressure decrease of at least 10 mm Hg within three minutes of standing".*

Method of checking for postural hypotension:

1. Let the patient rest in supine position for about 5 to 10 minutes
2. Check the blood pressure in supine position
3. Request the patient to stand up, taking care so that s/he does not lose balance and fall down
4. Wait for 1 to 3 minutes, with the patient standing
5. Check blood pressure in standing position after the patient has stood for 1 to 3 minutes
6. Compare the two values.

If systolic falls by at least 20 mmHg and/or diastolic falls by at least 10 mmHg, a diagnosis of postural (orthostatic) hypotension can be made.

Generally, systolic blood pressure is considered to be more important in diagnosing this condition. In addition, in clinical practice, we do consider the possibility of postural hypotension when:

• a patient has symptoms of postural hypotension, even if the fall in systolic blood pressure is less than 20 mmHg (especially if the fall is more than 10 mmHg)
• there is an increase in heart rate when the patient stands up from supine position, especially with symptoms of postural hypotension

Clinical decisions should be based more on symptoms of decreased cerebral perfusion than absolute blood pressure or heart rate measurements.

* Reference
Consensus statement on the definition of orthostatic hypotension, pure autonomic failure, and multiple system atrophy. The Consensus Committee of the American Autonomic Society and the American Academy of Neurology. Neurology 1996;46:1470.

Several mechanisms counteract the gravitational forces on blood and maintain systemic arterial pressure and cerebral perfusion upon assumption of the upright posture. Failure of these mechanisms can lead to a postural decrease in blood pressure. Postural hypotension is defined as a reduction of at least 20 mm Hg in systolic blood pressure or at least a 10 mm Hg decrease in diastolic blood pressure. Acute postural hypotension is usually due to fluid or blood loss and responds well to fluid repletion. Chronic postural hypotension is due to drugs or endocrine or neurogenic disorders. A functional classification based on severity of symptoms is useful in monitoring the patient‘s condition and documenting improvement with treatment. Whenever possible, the reversible causes of chronic postural hypotension should be treated. For symptomatic treatment, a stepped approach starting with nonpharmacologic measures is recommended. Fludrocortisone, midodrine, indomethacin, and atrial tachypacing are recommended, in that order, for patients in whom nonpharmacologic measures prove insufficient. Other drugs can be added if necessary. The goal of treatment is to make the patient as ambulatory and symptom-free as possible without causing supine hypertension.