Page 63 - Clinical Pearls in Cardiology

Arterial Pulse and Blood Pressure 51

result in falsely high spurious hypertension, due to the
phenomenon of cuff hypertension.
33. What is orthostatic or postural hypotension?
In healthy individuals, there often is a transient decrease
in blood pressure on standing due to pooling of blood in
the lower part of the body. But baroreceptor mediated
reflexes are triggered by this sudden shift of blood and
they cause an increase in heart rate and peripheral
vascular resistance. Thus the blood pressure usually
returns back to normal level immediately. These reflexes
are impaired in elderly persons and in those with
autonomic neuropathy, resulting in what is called as
orthostatic or postural hypotension.

Common causes of postural hypotension
• Reduced blood volume
• Drug-induced hypotension
• Altered vascular responses associated with aging
• Prolonged bed rest (usually >2 weeks)
• Disorders of autonomic nervous system

The American Autonomic Society and the American
Academy of Neurology has defined orthostatic or
postural hypotension as a decrease in systolic blood
pressure of at least 20 mm Hg or a decrease in diastolic
blood pressure of at least 10 mm Hg within 1 to 3 minutes
of standing upright.
34. What do you know about the circadian rhythms in
blood pressure value?
Normal changes in blood pressure follow a characteristic
circadian pattern. Blood pressure tends to be highest
in the early morning, shortly after arising from sleep. It