cvp 3rd year
TRANSCRIPT
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LEARNING OUTCOMES
By the end of this session the student
should be able to :
Explain the indications for a patientrequiring CVP monitoring
Identify the equipment required forcommencing CVP monitoring
Describe the nursing role, both in thecare and use of the central venousmonitoring line
Discuss the reasons for abnormalCVP readings.
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DEFINITION
Blood from the systemic veins flowsinto the right atrium.
The pressure in the right atrium is theCVP.
A catheter is passed via;
the subclavian vein or jugular vein into
the superior vena cava
to determine the venous return andintravascular volume of the rightatrium.
The normal value is 5-10cm H2O
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PURPOSE
To serve as a guide of fluid balancein critically ill patients
To estimate the circulating bloodvolume
To determine the function of the right
side of the heart
To assist in monitoring circulatoryfailure
None of these variables aremeasured directly; they must beinterpreted.
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Axillary veinCephalic vein
Median cubital vein
Basilic vein
ACCESS
External Jugular vein
Subclavian vein
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COMPLICATIONS
Carotid Artery Puncture
Pneumothorax
Air Embolism
Arrhythmia
Perforation of SVC orR. Atrium/Ventricle
Infection
Pleural Effusion
Extravasion of Infusate
Allergic reaction to catheter material
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EQUIPMENT
The equipment needed for measurement of
central venous pressure includes a sterile bag
of fluids (a) with attached fluid administration set (b),
an IV extension set (c), a manometer (d)
and a stopcock (e).
a.
b.
c.
d.
e.
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EQUIPMENT
IV extension
set to entry portof patientscentral line.
IV giving setto fluid bag.
Stopcock(Three way tap)
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DIRECTION OF FLOW
The white arrows indicate the direction of fluid flow.
Initially the white knob is turned straight up towards the manometer, allowing fluid to
flow from the fluid bag to the patient's catheter to assure the catheter is patent (a).
If fluid does not flow freely into the patient's catheter a valid CVP reading
will not be obtained.
Then the knob is turned toward the patient (b) and fluid will fill the manometer.
The manometer should not contain any air bubbles.
If air is present in the manometer or fluid line, let the fluids run, overfilling themanometer until all air is purged from the system.
Then turn the knob toward the fluids (c). The level of fluid in the manometer
will fall (the fluid is running into the patient's catheter) until the height of the
fluid column exerts a pressure equivalent to the patient's central venous pressure.
The top of the fluid column will slightly oscillate up and down as the animals'
heart beats and as the animal breathes.
a. c.b.
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POSITION OF PATIENT
3-way tap
manometer
FluidBag
Patient in supine position
CentralVenousAccess
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INTERPRETATION
An increase of above normal mayindicate weakening or failure of theright side of the heart, or excessive
intravascular volume
A pressure below 5cm H2O usuallyreflects an intravascular volume deficitor drug induced excessive vasodilation
CVP measurements must not beinterpreted on their own, but viewedalongside the patient's full clinicalpicture
(BP, Respiratory Pattern, Colour, Temperature)
Several measurements are requiredto identify a trend
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DETERMINANTS
Cardiac Competence(reduced ventricularfunction raises CVP)
Blood Volume(increased venousreturn raises CVP)
Intra Aortic &Intra Peritoneal
Pressure(raises CVP)
SystemicVascular Resistance
(raises CVP)
CVP