Blood Pressure Overview

Blood Pressure

• Arterial blood pressure: Measurement of the pressure exerted by blood as it flows through the arteries.
• Two blood pressure measurements:
  • Systolic pressure: During ventricular contraction.
  • Diastolic pressure: During ventricular relaxation, lower pressure that is always present.
• Pulse pressure: The difference between systolic and diastolic pressures.
• Blood pressure is measured in millimeters of mercury (mmHg) and written as a fraction, e.g. 120/80 (systolic/diastolic).

Determinants of Blood Pressure

• Factors influencing arterial blood pressure:
  • Pumping action of the heart: The forcefulness of the heart's contractions.
  • Peripheral vascular resistance: Resistance to blood flow in the arteries, influenced by factors like arteriosclerosis.
  • Blood volume: The amount of circulating blood.
  • Blood viscosity: The thickness of the blood, determined by hematocrit levels.

Factors Affecting Blood Pressure

• Age: Blood pressure tends to increase with age.
• Exercise: Physical activity can temporarily decrease blood pressure.
• Stress: Stress can cause a temporary increase in blood pressure.
• Race: Certain racial groups have higher rates of hypertension.
• Sex: Men generally have higher blood pressure than women before menopause.
• Medications: Some medications can impact blood pressure.
• Obesity: Excess weight can increase blood pressure.
• Diurnal variations: Blood pressure fluctuates throughout the day.
• Medical conditions: Certain health conditions can affect blood pressure.
• Body temperature: Fevers can increase blood pressure.

Classifying Blood Pressure

• Blood pressure classification helps determine if someone has hypertension or hypotension.

Hypertension

• Persistently elevated blood pressure above normal.
• Usually asymptomatic but can contribute to heart attacks.
• Two types:
  • Primary hypertension: Cause unknown.
  • Secondary hypertension: Result of an underlying medical condition.

Factors Associated with Hypertension

• Lifestyle factors that contribute to hypertension:
  • Cigarette smoking
  • Obesity
  • Excessive alcohol consumption
  • Lack of exercise
  • High cholesterol levels
  • Chronic stress

Hypotension

• Lower than normal blood pressure, usually a systolic reading below 85-110 mmHg.
• Types of hypotension :
  • Orthostatic hypotension (postural hypotension): Blood pressure drops when transitioning from a lying down to a sitting or standing position.
  • Caused by: Peripheral vasodilation, causing blood to pool in the extremities and away from the brain.

Causes of Hypotension

• Causes can include:
  • Certain analgesics like meperidine hydrochloride (Demerol)
  • Bleeding
  • Severe burns
  • Dehydration

Monitoring Hypotension

• Closely monitor hypotensive patients to prevent falls.

Blood Pressure Measurement

• Performed using a blood pressure cuff, sphygmomanometer, and stethoscope.
• Blood pressure cuff contains an inflatable bladder.

Sphygmomanometers

• Types include:
  • Aneroid (manual)
  • Digital
  • Doppler ultrasound

Cuff and Bladder Size

• Cuff width should be 40% of the limb's circumference or 20% wider than the limb's diameter.

Blood Pressure Measurement Sites

• Typically measured in the upper arm (brachial artery).
• May be measured on the forearm or wrist using electronic monitors.
• Thigh (popliteal artery) measurements are used in certain situations.

Blood Pressure Measurement Contraindications

• Avoid measuring blood pressure on limbs with:
  • Injuries or diseases
  • Casts or bandages
  • Prior breast or lymph node surgery on the same side
  • IV infusions or blood transfusions
  • Arteriovenous fistulas

Common Errors in Blood Pressure Measurement

• Factors that can lead to inaccurate readings:
  • Cuff too narrow or too wide
  • Arm unsupported
  • Arm above heart level
  • Insufficient rest prior to measurement
  • Cuff too loose or unevenly wrapped
  • Cuff deflated too quickly or too slowly
  • Failure to measure in the same arm
  • Assessment while eating, smoking, or in pain
  • Auscultatory gap not identified

This quiz covers the essentials of blood pressure, including systolic and diastolic measurements, and factors influencing arterial blood pressure. You will learn about the determinants of blood pressure such as heart function, vascular resistance, blood volume, and viscosity. Test your knowledge on these crucial concepts in cardiovascular health.