2. OBJECTIVES
At the end of this class, you should able to recollect.
Definition of Blood Pressure Its variations.
Measurement - Korotkoff sound
Factors contributing to B.P
Peripheral resistance
Regulation of BP
Immediate regulation
Short term regulation
Long term regulation.
Applied - Hypertension - Hypotension
Physiology of treatment.
3. ARTERIAL BLOOD PRESSURE
Definition : Arterial blood pressure can be
defined as the lateral pressure exerted
by the moving column of blood on the
walls of the arteries.
5. SIGNIFICANCE
1. To ensure the blood flow
To various organs.
2. Plays an important role
in exchange of nutrients
and gases across the
capillaries.
3. Required to form urine.
4. Required for the formation
Of the lymph.
6. Normal Values
Normal Adult range
Can fluctuate within a
wide range and still
be normal
Systolic/diastolic
100/60 - 140/80
7. Systolic B.P (S.B.P)
Defined as the maximum
B.P in the arteries
Attainable during systole.
Normal 120 + 20 mm Hg.
This is mainly contributed by
1. Force of heart beat
2. Normal blood volume
3. Cardiac output.
Normal range
90-140 mm Hg.
8. 02/16/1602/16/16
DIASTOLIC B.P (D.B.P)
Def--- as the minimum
pressure that is obtained at the
end of the ventricular diastole.
Normal range 60 -90 mm Hg.
1. It represents a constant load
on the arterial walls with
little or no fluctuation at all.
2. It is an index to the
peripheral resistance and
decides the filling of the
Coronary system.
10. MEAN ARTERIAL PRESSURE
Mean arterial .BP = DBP +
1/3 Pulse Pressure
normal = 95 mm Hg.
•Not the arithmetical mean but geometrical
mean.
•It is because the period of the systole is only
0.3 sec when compared to 0.5 sec of the
diastole.
12. PHYSIOLOGICAL VARIATION IN BLOOD
PRESSURE
A) Age
B) Build
C) Climate
D) Diurnal Variation
E) Exercise
F) Fever
G) Gestation
H) high Altitude
I) Infusion/ Intake
J) Pain
K) Posture
L) Sleep
M) sex
16. 3
RECOMMENDED BLOOD PRESSURERECOMMENDED BLOOD PRESSURE
MEASUREMENT TECHNIQUEMEASUREMENT TECHNIQUE
2.
• The cuff must be level with heart.
• If arm circumference exceeds 33 cm,
a large cuff must be used.
• Place stethoscope diaphragm over
brachial artery.
2.2.
•• The cuff must be level with heart.The cuff must be level with heart.
•• If arm circumference exceeds 33 cm,If arm circumference exceeds 33 cm,
a large cuff must be used.a large cuff must be used.
•• Place stethoscope diaphragm overPlace stethoscope diaphragm over
brachial artery.brachial artery.
1.
• The patient should
be relaxed and the
arm must be
supported.
• Ensure no tight
clothing constricts
the arm.
1.1.
•• The patient shouldThe patient should
be relaxed and thebe relaxed and the
arm must bearm must be
supported.supported.
•• Ensure no tightEnsure no tight
clothing constrictsclothing constricts
the arm.the arm.
3.
• The column of
mercury must be
vertical.
• Inflate to occlude the
pulse. Deflate at 2 to
3 mm/s. Measure
systolic (first sound)
and diastolic
(disappearance) to
nearest 2 mm Hg.
3.3.
•• The column ofThe column of
mercury must bemercury must be
vertical.vertical.
•• Inflate to occlude theInflate to occlude the
pulse. Deflate at 2 topulse. Deflate at 2 to
3 mm/s. Measure3 mm/s. Measure
systolic (first sound)systolic (first sound)
and diastolicand diastolic
(disappearance) to(disappearance) to
nearest 2 mm Hg.nearest 2 mm Hg.
StethoscopeStethoscope
MercuryMercury
machinemachine
17. Tapping sound 1
SBP
110 mm Hg
Banging sound 3
Muffing sound 4
DBP-
95 mm Hg
85 mm Hg
Recording of
arterial BP by
auscultatory
method
Korotkov
sounds
120 mm Hg
Murmurish 2
80 mm Hg No sound 5
AUSCULTATORY METHOD
This method was introduced by a Russian physician
Korotkov
18. CTORS MAINTAINING
OOD PRESSURE
1. Cardiac output (CO= SV X PR)
2. Circulating blood volume
(This mainly affects systolic B.P)
3. Elasticity of the vessel wall
4. Viscosity of blood
19. Viscosity is affected by
1. Cell count
2. Plasma proteins
3. Chemical composition like
CO2, O2 content,PH.
4. Temperature
5. Drugs like general anaesthetics.
All these factors influence
peripheral resistance through viscosity
20. 02/16/1602/16/16
Peripheral Vascular Resistance
It is defined as the resistance
offered to the flow of blood
by the blood vessels.
It is contributed by:
The Smooth muscles of the
arterioles in particular.
21. FACTORS AFFECTING BLOOD PRESSURE
Disease
Age
Heredity
Blood Volume
Weight
Diet
Hormones
Salt
Caffeine
Environmental
factors
Psychological factors
Stress/Anxiety
Gravity
Drugs
Alcohol
Time of day
22. 02/16/1602/16/16
BP = Cardiac output X PR
Peripheral resistance(PR) in a normal healthy young
adult is 20mm Hg/lit/mt.
Peripheral vascular resistance: depends upon
A) Velocity of blood
B) Viscosity of blood
C) Elasticity of the
vessels wall
D) Lumen of the vessels
E) Length of the vessels
F) Extra vascular
compression
BLOOD PRESSURE
100 = 5X20
23. 02/16/1602/16/16
Peripheral Resistance
Obsolute units: Dyne/sec/cm2
Pressure dyne/cm2
PR =
Flow cc/sec
= dyne/sec/cm2
P.R.U unit: (Relative unit) When there is a
difference of 1 mm Hg and a flow of 1ml/sec
then it is called one PRU unit.
36. 02/16/1602/16/16
Delayed or Intermediate Mechanism
Capillary fluid shift phenomenonCapillary fluid shift phenomenon:
Whenever there is an increase in blood pressure
more fluid is filtered through the capillary wall into
the interstitial space.
Blood volume decreases
and so BP itself decreases.
Reverse changes take
place when BP falls.
37. 02/16/1602/16/16
Delayed or Intermediate Mechanism
Renin –Angiotensin System
Whenever there is a fall in B.P, there is a
decrease in the blood flow to the kidney.
This results is ischaemic kidney.
Renin is released from J.G. cells
Renin
Angiotensin Angiotensin I
ACE
Angiotensin I Angiotensin II
ACE - Angiotensin Converting Enzyme
( Present in the lungs)
38. 02/16/1602/16/16
ACTION OF ANGIOTENSIN - II
1. Vasoconstriction
2. Aldosterone secretion
3. Stimulation of the
thirst centre
4. Increased absorption
of Na+
from PCT by
direct effect. As a result
. B.V ↑, C.O ↑. BP ↑
42. 02/16/1602/16/16
Renal –body fluid system:
↑ECF or Blood volume
- ↑ BP
B.P is brought back to
the normal level
↓ECF or Blood volume
- ↓BP
B.P is slowly raised to
the normal level.
↑ GFR ↑ urine output ↓ GFR BP ↓ urine output
44. Hypertension
Defined as an elevation of systolic
blood pressure
Persistent hypertension very common
30% of people over 50 are
hypertensive
Never diagnosed on one reading
Indication of cardiovascular disease
Trauma
Side effect of medication
45. 02/16/1602/16/16
↑ BP is called Hypertension
(Above 140/90 mm of Hg )
Primary
(Essential 90%)
Secondary
(10%)
46. Diseases Attributable to
Hypertension
Hypertension
Heart failure
Stroke
Coronary heart disease
Myocardial infarction
Left ventricular
hypertrophy
Aortic aneurysm
Retinopathy
Peripheral vascular disease
Hypertensive
encephalopathy
Chronic kidney failure
Cerebral hemorrhage
Adapted from: Arch Intern Med 1996; 156:1926-1935.
All
Vascular
51. Prevention
Reduce the risk of developing High Blood
Pressure by making lifestyle changes…..
Eat a healthy , well balanced diet
Reduce salt and fat intake
Exercise regularly
Stop smoking
Reduce alcohol and caffeine consumption to
recommended levels
Reduce weight
52. Hypotension
Defined in adults as a
systolic pressure below
100mm Hg
Rarely treated in this
country
53. 02/16/1602/16/16
↓ BP is called Hypotension
(Below 90/60 mm of Hg)
1. Hemorrhage
2. Dehydration
3. Vomiting
4. Diarrhea
5. Excessive
sweating
6.Adissons disease
7.Hypothyroidism
56. 02/16/1602/16/16
RECAP
At the end of this class, you should able to
recall.
1. Definition of Blood Pressure
2. Its variations.
3. Measurement - Korotkov sound
4. Factors contributing to B.P
5. Peripheral resistance
6. Regulation of BP
7. Immediate regulation
8. Short term regulation
9. Long term regulation.
10. Applied - Hypertension - Hypotension
When blood pressure rises the blood travelling along the arteries roughens the lining of the arteries. To understand why this happens, picture what occurs when you turn a tap on. At normal pressure the water travels in a straight line, but when you turn the tap on full blast the water spurts out in all directions. Before it comes out it has been pushing in all directions against the sides of the pipes. This is what happens to the blood in the arteries if you have high blood pressure and puts an extra strain on the heart.
Slide 5
Studies show that a multitude of diseases are attributable to hypertension.
They include:
• Heart failure
• Coronary heart disease
• Myocardial infarction
• Left ventricular hypertrophy and failure
• Aortic aneurysm
• Peripheral vascular disease
• Retinopathy
• Hypertensive encephalopathy
• Chronic kidney failure
• Cerebral hemorrhage
• Stroke
With so many diseases linked to hypertension, prompt and effective treatments have the potential to reduce many complications.
Dustan HP, et al. Arch Intern Med 1996; 156:1926-1935.
Postural Hypertension: is a fall in blood pressure that occurs when changing position from lying to sitting or from sitting to standing
Postural=change in position
Hypotension=fall in blood pressure to a low level
A fall in blood pressure leads to a reduced blood supply to organs and muscles; this can cause a variety of symptoms:
E.G Feeling dizzy
Changes in vision such as blurring
Feeling vague or muddled
You may be asked to take a patients blood pressure lying down
Some diabetic patients may suffer the symptoms of postural hypotension
