Vital Signs/Blood pressure

Blood Pressure

• Arterial blood pressure is a measure of pressure exerted by the blood as flows through the arteries. (measured by mmHg.)

• 120/80 mmHg (adults)

BP normal limits

Two Types of pressure measures:• Systolic pressure: as result of ventricles

contraction.• Diastolic pressure: when the ventricles are

at rest.• Pulse Pressure: difference between the

diastolic and systolic pressures (normal is 40)

Determinants of BP

• Cardiac output• Peripheral vascular

resistance• Blood volume• Blood viscosity (Hct.

> 60-65%)

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Factors Affecting BP• Age (elasticity of the arteries)• Exercise (wait 20-30min)• Stress• Race : African American males over 35 years have

higher BP than European males at the same age.• Gender: after puberty, females have lower BP than

males due to hormonal variations. • Medications• Obesity: predispose to hypertension.• Diurnal variations: BP lowest early in the morning,

then rises during the day• Disease process

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Assessing BP• Indirect

Sphygmomanometer and stethoscope Electronic Sphygmomanometer Doppler ultrasound

• Direct• (Invasive Monitoring) Arterial lines

Sites:• Upper arm (brachial artery)• Radial ?????• Thigh (popliteal artery)

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Hypertension• Cannot be diagnosed unless an elevated blood

pressure is found when measured twice at different times.

Types:2. Primary: unknown cause 1. Secondary: known cause• Associated factors include: arteriosclerosis,

smoking, obesity, alcohol, lack of physical activity, high blood cholesterol and stress.

• Rx. : treatment of secondary causes, life style changes and monitoring.

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Hypotension

• Is a BP that is below normal, that is systolic between 85 and 110 mmHg in an adult whose normal pressure is higher than this.

• Orthostatic hypotension: is a BP that falls when the client sits or stands.

• Causes: drugs, bleeding, severe burn and dehydration

• Management : supine position 2-3min., V/s, prevent falls, Rx of the cause.

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Oxygen Saturation

• Pulse Oximeter: noninvasive device that estimates a client’s arterial blood oxygen saturation (SaO2).

• Detects hypoxemia before clinical signs and symptoms

• Normal SaO2 is 95%-100%• SaO2 below 70% is life threatening.

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