Transcript Arterial and Venous Blood Press

Arterial and venous blood pressures
Arterial Blood Pressure (BP)
=
The lateral pressure force generated by the pumping action of
the heart on the wall of aorta & arterial blood vessels per unit
area.
OR =
Pressure inside big arteries (aorta & big vessels).
■ Measured in (mmHg), & sometimes in (cmH2O), where
1 mmHg = 1.36 cmH2O.
■ Of 2 components:


systolic … (= max press reached)
diastolic … (= min press reached)
Arterial Blood Pressure (continued)
In normal adult  120/80 mmHg.
■ Diastolic pressure is more important, because diastolic period
is longer than the systolic period in the cardiac
cycle.
■ Pulse pressure = Systolic BP – Diastolic BP.
■ Mean arterial pressure = Diastolic BP + 1/3 Pulse press.
Factors affecting ABP:
■ Sex … M > F …due to hormones/ equal at menopause.
■ Age … Elderly > children …due to atherosclerosis.
■ Emotions … due to secretion of adrenaline &
noradrenaline.
■ Exercise … due to  venous return.
■ Hormones … (e.g. Adrenaline, noradrenaline, thyroid
H).
■ Gravity …  Lower limbs > upper limbs.
■ Race … Orientals > Westerns … ? dietry factors, or
weather.
■ Sleep …  due to  venous return.
■ Pregnancy … due to  metabolism.
Factors determining ABP:
Blood Pressure = Cardiac Output X Peripheral Resistance
(CO)
Flow
(BP)
■ BP depends on:
(PR)
Diameter of
arterioles
1. Cardiac output  CO = SV X HR.
2. Peripheral resistance.
3. Blood volume.
Total peripheral resistance = TPR



-- combined resistance of all vessels
-- vasodilation  resistance decreases
-- vasoconstriction  resistance increases
Classification of Blood Pressure

JNC (Joint National Committee ) 7 Guidelines (2003)
Category
SBP
 Normal
< 120
 Prehypertension
120-139
 Stage 1
140-159
or

Stage 2
≥ 160
or
or
90-99
or
DBP
< 80
80-89
≥ 100
Definitions and Classification
of BP Levels (mmHg)
Category
Systolic
Diastolic
Optimal
<120
and
<80
Normal
120-129
and/or
80-84
High Normal
130-139
and/or
85-89
Grade 1
Hypertension
140-159
and/or
90-99
Grade 2
Hypertension
160-179
and/or
100-109
Grade 3
Hypertension
≥ 180
and/or
≥ 110
Isolated Systolic
Hypertension
≥ 140
and
< 90
Journal of Hypertension 2007;25:1105-1187 European Society of Hypertension, European Society of Cardiology

Hypertension with no known cause (primary,
formerly, essential hypertension) is most
common.

Hypertension with an identified cause (secondary
hypertension) is usually due to a renal disorder.

Usually, no symptoms develop unless
hypertension is severe or long-standing.
Measurement

Arterial pressure is most commonly measured via a
sphygmomanometer.

Invasive measurement
Noninvasive measurement

Invasive measurement

Arterial blood pressure (BP) is most accurately
measured invasively through an arterial line .

Invasive arterial pressure measurement with
intravascular cannulae involves direct measurement of
arterial pressure by placing a cannula needle in an artery
(usually radial ,femoral ,dorsalis pedis or brachial)
Noninvasive measurement


Palpation method
Auscultatory method





Is your patient ready?
If your patient has finished a cigarette or an alcoholic
beverage within the last 15 minutes the readings will be
altered.
If they haven’t sat quietly for at least 5 minutes or are
talking during the procedure, the readings will be altered.
Systolic and diastolic BP's in hypertensive and
normotensive patients increase with talking
And if you have placed the cuff over a shirt sleeve the
readings will not be reliable.
Brachial artery is the most common
measurement site
Close to heart
Convenient measurement
1. Use appropriate size BP cuff


Is the cuff you are using sized for the patient? A cuff too
large can cause reading to be lower than actual and a
cuff too small can cause reading to be higher than
actual.
Cuff sizes are:Small Adult 17-25cm/Standard Adult 2333cm/Large Adult 31-40cm/Thigh 38-50cm.

2. Position patient
Patient should be seated with back and arms
supported, feet on floor, and legs uncrossed
with upper arm at heart level
3.Measure baseline BP bilaterally




Cuff applied 1 inch above crease at elbow
Locate brachial artery
Palpate radial pulse
Inflate cuff until pulse disappears
Palpation method



The blood pressure can be measured in noisy
environment
Only the systolic pressure can be measured (not DP)
The technique does not give accurate results for infants
and hypotensive patients
Auscultatory method



Pulse waves that propagate through the brachial artery,
generate Korotkoff sounds.
There are 5 distinct phases in the Korotkoff sounds,
which define SP and DP
The Korotkoff sounds are ausculted with a stethoscope
Korotkoff sounds

First Phase


Second Phase


A clear tapping sound; onset of the sound for two
consecutive beats is considered systolic
The tapping sound followed by a murmur
Third Phase

A loud crisp tapping sound

Fourth Phase


Abrupt, distinct muffling of sound, gradually
decreasing in intensity
Fifth Phase

The disappearance of sound, is considered
diastolic blood pressure- two points below the last
sound heard
RECOMMENDED BLOOD PRESSURE
MEASUREMENT TECHNIQUE
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3
Venous Pressure
Venous Pressure
Venous Pressure generally refers to the
average pressure within venous
compartment of circulation
 Blood from all the systemic veins flows into
the right atrium of the heart, therefore the
pressure in the Rt atrium called Central
Venous pressure

How to measure the CVP ??
 Direct:
by catheter introduced into large
thoracic veins
 Indirect:
pressure
Is estimated from Jugular venous
Jugular Venous Pulse (JVP)
There is no valves between the Rt atrium and
the Internal Jugular Vein . So the degree of
distension of this vein is dictated by the Rt
atrium pressure.
 Pressure changes transmitted from right
atrium
 The right internal jugular is the best neck vein
to inspect
 Provides information about hemodynamic
changes in right atrium & ventricle

Anatomy Of IJV
Cont….
The internal
jugular vein is
lateral to
carotid artery &
deep to
sternomastoid
muscle.
 External jugular
is superficial to
sternomastoid

JVP waves
Cont….



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
A a positive wave due to atrial contraction.
C a positive deflection due closure of tricuspid
(carotid pulsation)
X a negative deflection due to atrial relaxation
V a positive deflection due to filling of the right
atrium against the closed tricuspid valve during
ventricular contraction (venous return)
Y a negative deflection due to emptying of the
right atrium upon ventricular relaxation
Abnormalities of wave
Prominent ‘a’ wave :
Right atrial and right ventricular hypertrophy
(due to P.HTN or P.stenosis)
Tricuspid stenosis.
 Cannon wave:
Large ‘a’ wave produce when Rt atrium
contract against closed tricuspid valve. This
seen in complete heart block

Cont…
Kussmaul sign:
A paradoxical rise of JVP on inspiration.
Causes:
Constrictive pericarditis
Cardiac tamponade
Sever Rt ventricular failure

Difference between arterial and venous
pulsation in neck
Change in posture ?
 Change in respiration ?
 Abdomino-jugular reflux ?
 Pulsation pattern ?
 Palpation ?
 Occlusion ?

How measure JVP ?
LOOK
 CONFIRM
MEASURE

Method
Position 45 degree
 Rest the pt head on pillow to ensure neck
muscle relax, and slightly tilted toward the left
side.
 look acorss the neck from the Rt side of the
pt.
 Identify the Jugular vein
 Confirm the pulse.

Cont..
Identify the upper limit of venous pulsation
 JVP is measured by two pencils method
 Place one pencil at sternal angle vertical to
ground & other pencil at upper limit of
venous pulsation horizontal to the ground
 Measure length of the verticbal pencil in
cm btw the sternal angle & where it is
crossed by the horizontal pencil.
 Normal JVP up to 3 cm

Causes of raised JVP
Right heart failure
Constrictive pericarditis
Superior vena cava obstruction
Pericardial effusion
Cardiac tamponade
Tricuspid valve disease
Cardiac tamponade

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
Cardiac tamponade: the accumulation of fluid in the
pericardium in an amount sufficient to cause serious
obstruction to the inflow of blood to ventricle results in
cardiac tamponade.
The three principal features of tamponade are:
1.elevation of intracardiac pressures
2.limitation of ventricular fillng
3.reduction of cardiac output
Beck triad:
1.increased
jugular venous
pressure
2.hypotension
3.diminished heart sounds
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