CENTRAL VENOUS PRESSURE LEARNING OUTCOMES By the end of this session the student should be able to : Explain the indications for a patient requiring

CENTRAL VENOUS PRESSURE



LEARNING OUTCOMES

By the end of this session the studentshould 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.


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 6-12cm H2O


PURPOSE

• To serve as a guide of fluid balance in critically ill patients (To guide the administration of fluid or diuretics.)

• 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.


Axillary veinCephalic vein

Median cubital vein

Basilic vein

ACCESS

External Jugular vein

Subclavian vein


COMPLICATIONS

• Carotid Artery Puncture

• Pneumothorax

• Air Embolism

• Arrhythmia

• Perforation of SVC or R. Atrium/Ventricle

• Infection

• Pleural Effusion

• Extravasion

• Allergic reaction to catheter material


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.


EQUIPMENT

IV extension set to entry port of patients central line.

IV giving setto fluid bag.

Stopcock(Three way tap)


-Patient Preparation: *Place the patient in the supine position with the head of the bed flat.

*Locate and mark the phlebostatic axis with the skin marker.


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.

a. c.b.


-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.


-Take the CVP reading when the fluid level stabilizes at the end of expiration.

-Turn the stopcock off to the manometer and run the IV fluids through the central venous line as prescribed.

Post care: Patient: Return the patient to

correct position. Nurse: Handwash. Environment: Return equipment. Documentation: Document the

reading.


POSITION OF PATIENT

3-way tap

manometer

FluidBag

Patient in supine position

CentralVenousAccess

phlebostatic axis


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


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


REFERENCES

Henderson N., (1997) Central Venous Lines Nursing Standard 11:42, pp49-56

Mallett J., (2000) The Royal Marsden NHS TrustDougherty 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.


Documents

CENTRAL VENOUS PRESSURE LEARNING OUTCOMES By the end of this session the student should be able to : Explain the indications for a patient requiring