LL3b VITAL SIGNS BLOOD PRESSURE

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LL3b VITAL SIGNSBLOOD PRESSURE

• The force exerted by the blood against the vessel
  walls.
• Blood Pressure (BP) reflects the balance of
  cardiac output
• peripheral vascular resistance
• blood volume blood viscosity
• elasticity of arteries
• and is influenced by age, stress, race,
  medication and diurnal variation.

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MEASUREMENT

• The measurement indicates the height at which the
  BP can raise the column of mercury (or other
  measurement means) as per visual gauge.
• BP is measured by means of a standard unit of
  measurement - millimetres of mercury in a column
  (mmHg) or KiloPascals (S.I. unit)

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• BP reflects HAEMODYNAMIC
  FACTORS within the Circulatory System
• It is the product of Cardiac Output (CO)
  Peripheral resistance (PR) -
• BP CO X R

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• BP varies in different blood vessels.
• Clinically the term BP refers to Systemic
  arterial blood pressure.
• There is no such value as a "normal" BP because
  it varies from individual to individual AND from
  moment to moment -
• but a NORMAL BP RANGE can be taken as between 100
  / 60 --- 150 / 90 mmHg

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FACTORS AFFECTING BLOOD PRESSURE

• Age, gender, race/ethnic origin, emotion,
  exercise, sleep, time of day, state of digestion
  / ingestion of food
• The Autonomic Nervous System Renin- Angiotensin
  - Aldosterne System is responsible for
  controlling the BP and keeping it within the
  normal range.

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• SYSTOLIC PRESSURE -
• is determined by the amount of blood being
  forced into the aorta and arteries with each
  ventricular contraction
• DIASTOLIC PRESSURE -
• provides information about the degree of
  Peripheral Resistance and depends on the level of
  the systolic pressure.

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PRACTICAL CONSIDERATIONS WHEN RECORDING BP's

• Explanation, patients reaction, variability in
  BP posture of client
• Position of arm application of cuff position of
  manometer
• Estimation of systolic pressure number of
  measurements times of measurement

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• Ausculatory measurement of systolic diastolic
  pressure
• indications for measurement on both or only one
  arm
• measurement re children
• follow up measurement - how often and why?

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MEASUREMENT SOUNDS

• Korotkov Sounds ( based on O'Brien O'Malley
  1981)
• Phase Sound mmHg Pressure
• 1 Sharp, clear 120 Systolic
• 2 Blowing. swishing 110
• 3 Sharp, but softer than in 1 90 )
• 4 Muffled, fading 80 ) Diastolic
• 5 No sound lt80

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HYPERTENSION

• If a reduced arterial wall elasticity exits
  (eg arteriosclerosis) there is greater
  resistant to blood flow - BP rises. Systolic
  pressure is more elevated than the diastolic.
• DIAGNOSIS - is made when - 2 or more diastolic
  readings are 90 mmHg or higher OR Systolic
  reading is more than 140 mmHg

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HYPOTENSION

• A persistently low BP is relatively uncommon but
  conditions of temporary lowered BP are more
  common. eg haemorrhage or fainting
• Low BP can be associated with illness state and
  has the potential to be life threatening.

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PULSE

• A peripheral pulse - wave that travels through
  the arterial system following the ejection of the
  cardiac ventricle against the walls of the aorta.
• Pulse is palpated by lightly compressing the
  artery against underlying bone or muscles
• Assessing a pulse offers valuable data for
  determining the integrity of the cardio vascular
  system(CVS)

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• Pulse rate indirectly measures the hearts output.
  
• Slow OR Rapid OR Irregular pulse may indicate the
  hearts inability to deliver an adequate cardiac
  output.
• Pulse Strength indicates volume of blood being
  ejected.
• The Peripheral pulse indicates the status of
  blood perfusion to the area served by that
  arterial pathway - eg femoral pulse in the leg

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References

• Potter,A. Perry,A. (1997) Fundamentals of
  Nursing, Concepts, Process Practice St Louis
  Mosby Ch 32 p 594
• Taylor,C. Lillis,C. LeMonde,P. (1997)
  Fundamentals of Nursing - The Art Science of
  Nursing Care. Philadelphia Lippincott Ch25
  p432