Blood Pressure

1. Blood Pressure

2. Arterial blood pressure is a measure of the pressure exerted by the blood as it flows through the arteries. The systolic pressure is the pressure of the blood as a result of contraction of the ventricles.

3. Diastolic pressure: is the pressure when the ventricles are at rest. Diastolic pressure: is the lower pressure present at all times within the arteries. Pulse pressure: the differences between the two called the

4. Determinants of blood pressure • Pumping action of the heart: when it is weak, less blood is pumped into arteries "lower cardiac output", and the blood pressure decreases. • Peripheral vascular resistance: can increase blood pressure especially the diastolic pressure. Some factors that create resistance in the arterial system are the capacity of the arterioles and the capillaries, the compliance of the arteries, and the viscosity of the blood

5. Determinants of blood pressure • Blood volume; when the blood volume decreases as a result of hemorrhage, the blood pressure decreases because of the decreased fluid in the arteries. • Blood viscosity; blood pressure is higher when the blood is highly viscous "thick" that is, when the proportion of RBC to the blood plasma is high.

6. Factors affecting Blood Pressure • Age; the pressure rises with age, reaching a peak at the onset of puberty, and then tend to decline. • Exercise; physical activity increases the cardiac output and hence in blood pressure; thus 20-30 minutes of rest following exercise is indicated before the resting blood pressure can reliably assessed. • Stress; stimulation of the nervous system increases cardiac output and vasoconstriction of the arterioles, however severe pain can decrease blood pressure greatly by inhibiting the vasomotor center and provide vasodilatation

7. Factors affecting Blood Pressure • Race (African American males over 35 years have higher BP than European American males) • Gender; after puberty, female usually have lower blood pressure than males at the same age. After menopause the female has higher blood pressure than males • Medications • Obesity; predispose to high blood pressure

8. Factors affecting Blood Pressure • Diurnal variations; pressure is usually lowest early in the morning when metabolic rate is low. • Disease process; any condition affecting the cardiac output, blood volume, blood viscosity, and compliance of the arteries has a direct effect on the blood pressure.

9. Hypertension Hypertension; an abnormally high blood pressure, over 140mm Hg systolic and 90 mm Hg diastolic. Factors associated with hypertension • Thickening of the arterial walls, which reduces the size of the arterial lumen • Inelasticity of the arteries • Lifestyle such as cigarette smoking • Obesity • Lack of physical exercise • High blood cholesterol level • Continued exposure to stress

11. Hypotension Blood pressure below normal that is systolic reading between 85-110mm Hg. Orthostatic hypotension, is a blood pressure that falls when the client sits or stands. It is usually the result of peripheral vasodilatation in which blood leaves the central body organs especially the brain and moves to the periphery, often causing the person to feel faint.

12. Causes of hypotension Hypotension can be caused by: • Analgesics • Bleeding • Severe burn • Dehydration It is important to monitor hypotensive clients carefully to prevent falls.

13. Assessing for orthostatic hypotension: • Place the client in a supine position for 10 minutes • Record the client's pulse and blood pressure • Assist the client to slowly sit or stand. Support the client in case of faintness • Immediately recheck the pulse and blood pressure in the same sites as previously. • Repeat the pulse and blood pressure after 3 minutes. • Record the results, a rise in pulse of 15 to 30 beats per minute or a drop in blood pressure of 20mmHg systolic or 10 mmHg diastolic indicates orthostatic hypotension

14. Equipments used to assess pulse and blood pressure • Stethoscope; is used to auscultate and assess body sounds including the apical pulse and the blood pressure • Sphygmomanometer; is used to assess blood pressure consist of cuff, good selection of the cuff in order to obtain accurate blood pressure.

17. Blood pressure sites Assessing the blood pressure on a client’s thigh is indicated in these situations: • The blood pressure can not be measured on either arm due to burn or other trauma • The blood pressure in one thigh is to be compared with the blood pressure in the other thigh

18. Blood pressure is not measured on a particular clients’ limb in the following situations: 1)The shoulder, arm, or hand is injured or diseased. 2) The client has had surgical removal of axilla lymph nodes on that side, such as for cancer. 3) The client has intravenous infusion in that limb 4) The client has an arteriovenous fistula for dialysis in that limb

19. Oxygen Saturation • A pulse oximeter; is a non invasive device that measures a client's arterial blood oxygen saturation by means of a sensor attached to the client's finger, toe, nose, earlobe, or forehead. • The pulse oximeter can detect hypoxemia before clinical signs and symptoms such as dusky skin color and dusky nail bed color.

22. Factors affecting oxygen saturation reading • Hemoglobin; if the hemoglobin is fully saturated with oxygen, the saturation will appear normal even if the total hemoglobin level is low • Circulation • Activity; shivering or excessive movement of the sensor site may interfere with accurate reading. • Carbon monoxide poisoning.