hypertension

Hypertension

Hypertension , or high blood pressure , is defined as a systolic blood pressure greater that 140 mm Hg over a sustained period , based on the average of two or more blood pressure measurements taken in two or more contact with the healthcare provider after an initial screening (Smeltzer , 2004 ,

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To further understand hypertension , the concept of blood pressure shall be discussed . Arterial blood pressure is a measure of the pressure exerted by the blood as it flows through the arteries . There are two blood pressure measurements because the blood moves

in waves , the systolic pressure and the diastolic pressure . The systolic measure is the pressure of the height of the blood wave as a result of ventricle contraction . On the other hand , the diastolic pressure is the pressure when the ventricles are at rest hence it is the lower pressure (Kozier 2004 ,

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Blood pressure is written as a fraction with the systolic pressure over the diastolic pressure and is measured with a sphygmomanometer in millimeters of mercury or mm Hg . Average blood pressure of a normal adult is 120 /80 mm Hg and its range varies by age . For newborns , its normal value is 65 /41 mm Hg , for children 1 to 4 years old it ranges from 90-99 /60-65 mm Hg . Children from 5 years to 12 should have the normal blood pressure of 100-110 /56-60 mm Hg (Burckhardt , 2007

Blood pressure is determined by four factors . These are the heart 's pumping action , peripheral vascular resistance , blood volume , and blood viscosity . The blood pressure decreases when the heart 's pumping action is weak because less blood is pumped into the arteries resulting in lower cardiac output . On the other hand , when the heart pumps strongly there is an increase in the volume of the blood pumped into the blood circulation which results in a higher cardiac output , increasing blood pressure (Kozier , 2004 ,

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If there is resistance in the arterial system , blood pressure can increase . this is because a much higher pressure is needed to combat the resistance brought about by constricted blood vessels . Blood volume greatly determines circulation . So when the blood volume decreases , the blood pressure will also decrease due to the decrease in circulating blood volume . Also , when the blood volume increases , the blood pressure also increases . Circumstances when the blood volume will decrease will be because of severe bleeding or dehydration and blood volume will increase when there is rapid intravenous infusion or inability of the kidneys to excrete fluids (Kozier , 2004 ,

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Blood viscosity refers to the thickness of the blood in terms of the amount of particles or elements present in it . Blood pressure is increase when the blood is highly viscous , especially when the red blood cells are higher in proportion to the blood plasma . This is also known as the hematocrit , the proportion of the red blood cells in relation to the blood plasma (Kozier , 2004 ,

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Not only physiological factors like those...