hypotension
hypotension A low arterial blood pressure. The range of blood pressure in health is quite wide, and the term hypotension is not applied simply to an individual whose blood pressure is habitually at the low end of the normal range (say, 110/60 mm Hg). Rather, it refers to some abnormal situation when the blood pressure falls, such as in fainting, after serious haemorrhage, in heart failure, or in shock. Postural hypotension refers to a fall in blood pressure on standing up. Significant hypotension is that which deprives the brain of an adequate blood supply. The brain ‘defends itself’ against this by widening its blood vessels, but a profound fall in blood pressure (below about 70/40 mm Hg) is beyond the limit of this compensation, and consciousness is lost.
See blood circulation; blood pressure.
Stuart Judge
See blood circulation; blood pressure.
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hypotension
