Postural Hypotension

Postural hypotension is defined as a reduction in systolic blood pressure of 20mmHg or more after standing for at least one minute (Miller, 1999). Also known as orthostatic hypotension, it is a common problem in older people, affecting 10-33% of them (Harris et al, 1991; Patel et al, 1993). VOL: 97, ISSUE: 03, PAGE NO: 39Phil Jevon, BSc, PGCE, RN, is a resuscitation officer, Walsall Hospitals NHS TrustThe prevalence of postural hypotension increases with age and it arises as a complication of a number of diseases, for example diabetes. It can present with clinical symptoms of dizziness, syncope and falls when the patient changes position. Although it may seem to be a relatively harmless phenomenon, patients safety and quality of life can be seriously affected. An understanding of the causes, together with appropriate nursing management, is essential. Maintaining blood pressure The body needs to maintain blood pressure to ensure adequate perfusion of organs, particularly when an organs functional demands increase. This relies on the integrity of the heart and blood vessels, maintenance of intravascular volume and various circulating and local vasoactive agents (Mathias and Kimber, 1999).

Blood pressure is regulated in part by baroreceptors, which are located in the aortic arch, carotid arteries and carotid sinus. By influencing the heart rate and peripheral vascular resistance via the autonomic nervous system, these help to compensate for transient changes in arterial pressure, maintaining it at a constant level. Age-related changes in the baroreflex mechanisms can precipitate postural hypotension. The baroreflex-mediated heart rate response to both hypotensive and hypertensive stimuli can become impaired. In addition, blood pressure regulation can be affected by age-related and disease-related cardiovascular changes, such as atherosclerosis. Arterioles are less able to constrict in response to rapid changes in position, for example when standing up, which makes older people more susceptible to postural hypotension (Andresen, 1998; Miller, 1999).

Categories