CVP MONITORING

1. CENTRAL VENOUS PRESSURE
LEARNING OUTCOMES
By the end of this session the student
should be able to :
• Explain the indications for a patient
requiring CVP monitoring
• Identify the equipment required for
commencing CVP monitoring
• Describe the nursing role, both in the
care and use of the central venous
monitoring line
• Discuss the reasons for abnormal
CVP readings.

2. CENTRAL VENOUS PRESSURE
DEFINITION
Blood from the systemic veins flows
into the right atrium.
The pressure in the right atrium is the
CVP.
A catheter is passed via;
the subclavian vein or jugular vein into
the superior vena cava
to determine the venous return and
intravascular volume of the right
atrium.
The normal value is 5-10cm H2O

3. CENTRAL VENOUS PRESSURE
PURPOSE
• To serve as a guide of fluid balance
in critically ill patients
• To estimate the circulating blood
volume
• To determine the function of the right
side of the heart
• To assist in monitoring circulatory
failure
• None of these variables are
measured directly; they must be
interpreted.

4. CENTRAL VENOUS PRESSURE
Axillary vein
Cephalic vein
Median cubital vein
Basilic vein
ACCESS
External Jugular vein
Subclavian vein

5. CENTRAL VENOUS PRESSURE
COMPLICATIONS
• Carotid Artery Puncture
• Pneumothorax
• Air Embolism
• Arrhythmia
• Perforation of SVC or
R. Atrium/Ventricle
• Infection
• Pleural Effusion
• Extravasion of Infusate
• Allergic reaction to catheter material

6. CENTRAL VENOUS PRESSURE
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.

7. CENTRAL VENOUS PRESSURE
EQUIPMENT
IV extension
set to entry port
of patients
central line.
IV giving set
to fluid bag.
Stopcock
(Three way tap)

8. CENTRAL VENOUS PRESSURE
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 the
manometer 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.

9. CENTRAL VENOUS PRESSURE
POSITION OF PATIENT
3-way tap
manometer
Fluid
Bag
Patient in supine position
Central
Venous
Access

10. CENTRAL VENOUS PRESSURE
INTERPRETATION
• An increase of above normal may
indicate weakening or failure of the
right side of the heart, or excessive
intravascular volume
• A pressure below 5cm H2O usually
reflects an intravascular volume deficit
or drug induced excessive vasodilation
• CVP measurements must not be
interpreted on their own, but viewed
alongside the patient's full clinical
picture
(BP, Respiratory Pattern, Colour, Temperature)
• Several measurements are required
to identify a trend

11. CENTRAL VENOUS PRESSURE
DETERMINANTS
Cardiac Competence
(reduced ventricular
function raises CVP)
Blood Volume
(increased venous
return raises CVP)
Intra Aortic &
Intra Peritoneal
Pressure
(raises CVP)
Systemic
Vascular Resistance
(raises CVP)
CVP

12. CENTRAL VENOUS PRESSURE
REFERENCES
Henderson N., (1997) Central Venous Lines
Nursing Standard 11:42, pp49-56
Mallett J., (2000) The Royal Marsden NHS Trust
Dougherty L., Manual of Clinical Nursing
Procedures, Fifth Edition
Oxford; Blackwell Science,
pp630-635.
Mc Dermott M., (1995) Central Venous Pressure
Nursing Standard 9:35, pp54
Nursing Standard., (1999) Quick Reference Guide 6.
Central Venous Lines
Nursing Standard 13:42.