Blood Pressure PPT

Understanding Blood Pressure

  • Sphygmomanometer: Device used to measure blood pressure.

  • Blood Pressure (BP): Refers to the force of blood against artery walls.

Factors Affecting Blood Pressure

  • Key Influencing Factors:

    • Force of blood from the heart.

    • Volume of blood in circulation.

    • Size (diameter) of arteries.

    • Flexibility of arterial walls.

Components of Blood Pressure

1. Cardiac Output (CO)

  • Amount of blood the heart pumps per minute.

  • Influences BP alongside peripheral resistance.

2. Peripheral Resistance (PR)

  • Opposition faced by blood as it exits the heart.

BP Formula

  • BP = CO × PR.

Neural Factors Influencing Blood Pressure

  • Sympathetic Nervous System:

    • Promotes vasoconstriction (narrowing of blood vessels).

    • Increases blood pressure.

  • Parasympathetic Nervous System:

    • Minimal impact on blood pressure.

Renal Factors in Blood Pressure Regulation

  • Kidneys play a crucial role:

    • Regulate blood pressure by managing blood volume.

    • High blood pressure leads kidneys to excrete more water.

    • Low blood pressure triggers release of renin, forming angiotensin II (a vasoconstrictor) that adjourns sodium and water reabsorption.

Other Factors Influencing Blood Pressure

  • Temperature Effects:

    • Heat promotes vasodilation.

    • Cold enhances vasoconstriction.

  • Chemicals affecting BP levels:

    • Epinephrine increases heart rate and blood pressure.

  • Dietary Factors:

    • Low salt, saturated fats, and cholesterol intake help manage hypertension.

Summary of Blood Pressure Influencing Factors

  • Factors that increase blood pressure include:

    • Decreased blood volume.

    • Increased stroke volume.

    • Increased heart rate, viscosity, and cardiac output.

  • Vasoconstriction also raises BP.

Types of Blood Pressure

1. Systolic Blood Pressure

  • Pressure during ventricular contraction (higher number).

2. Diastolic Blood Pressure

  • Pressure during ventricular relaxation (lower number).

Blood Pressure Measurement Techniques

  • Auscultatory Method: Most commonly used to measure systemic arterial BP using a sphygmomanometer on the brachial artery.

  • Blood pressure expressed as systolic / diastolic in mm Hg (e.g., 120/80 mm Hg).

Korotkoff Sounds during Measurement

  1. Clear tapping = Systolic BP.

  2. Tapping followed by murmur.

  3. Loud, crisp tapping.

  4. Abrupt muffling.

  5. Sound disappears = Diastolic BP.

Blood Pressure Measurement Process

1. Prepare the Patient

  • Rest for 3-5 minutes; avoid caffeine, alcohol, tobacco, and exercise prior.

2. Setup

  • Cuff applied above elbow crease; locate brachial artery.

  • Inflate cuff until pulse is not detectable (around 180-200 mm Hg).

3. Measure

  • Slowly release air and listen for the first sound (systolic) and last sound (diastolic) to record BP.

Understanding BP Readings

  • BP readings may vary throughout the day; usually higher in the morning.

Blood Pressure Levels

Category

Systolic Pressure

Diastolic Pressure

Normal

Lower than 120

Lower than 80

Pre-Hypertension

120-139

80-89

Hypertension Stage 1

140-159

90-99

Hypertension Stage 2

160 or Higher

100 or Higher

Consequences of Hypertension

  • Can lead to:

    • Enlarged heart, heart failure.

    • Aneurysms.

    • Kidney failure (due to narrowed blood vessels).

    • Increased risk of heart attack, stroke, and blindness.

Open Ended Questions

  • Define blood pressure in your own words.

  • What is hypertension?

  • Why is hypertension dangerous?

  • Identify the role of Korotkoff sounds in determining blood pressure.