Postural and Postprandial Hypotension: Approach to Management

Kannayiram Alagiakrishnan, MD, MPH, FRCPC, ABIM

Disclosures

Geriatrics and Aging. 2007;10(5):298-304. 

In This Article

Postural Hypotension

Orthostatic or postural hypotension is a condition in which subjects experience a systolic blood pressure drop of 20 mm Hg or more, or a diastolic blood pressure drop of 10 mm Hg or more, with or without an increase in heart or pulse rate, with or without symptoms, and within 3 minutes after standing (Figure 1).[2] The prevalence of PH is lowest among community-dwelling older adults (5-30%)[3,4,5] and is usually higher among hospitalized individuals (52-69%)[1,6] and those living in long-term care facilities (50%).[7]

Clinical Signs of Postural Hypotension

The normal blood pressure response that occurs when an individual moves from a supine to a standing position is a small reduction (<10 mm Hg) in systolic blood pressure and a small increase in diastolic blood pressure (approximately 2.5 mm Hg).[8] In the supine position, about 30% of the blood is in the thorax; when the individual stands, about 500-700 mL of blood pools in the lower extremities. This results in a decreased venous return and decreased cardiac output and hypotension, which, in turn, trigger the baroreceptors. Increased sympathetic activity and decreased vagal tone result, which cause an increase in heart rate, stroke volume, and peripheral resistance to resume normalization of blood pressure. During changes in posture, cardiovascular, autonomic, musculoskeletal, renal, and endocrine systems help to maintain blood pressure. With aging and hypertension, baroreflex sensitivity decreases[9,10] and an increase in vascular stiffness occurs.[11] Vascular stiffness has been associated with a reduction of the baroreflex sensitivity.[12,13] Reduced baroreflex sensitivity is the main mechanism that causes PH.

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