Читать книгу Understanding Anatomy and Physiology in Nursing - John Knight - Страница 139

Janet has experienced postural hypotension which has caused her fainting episode. On standing, blood pressure (BP) will fall as gravity pulls blood downwards. This drop is usually quickly detected by the baroreceptors and the heart rate is increased, and blood vessels undergo vasoconstriction to maintain BP. This baroreceptor response tends to become less efficient (blunted) with age. Janet takes a combined beta blocker and diuretic pill to treat her hypotension and this could significantly increase the risk of postural hypotension.

The beta blocker component slows Janet’s heart rate reducing her cardiac output while the diuretic will increase urine production, lowering Janet’s blood volume. Janet will require further assessment to determine if there are any other underlying causes for her postural hypotension. Based on this episode, Janet should be advised to rise slowly to allow her BP to normalise and she may have to be switched to a different type of antihypertensive medication.