Central Venous Pressure and Central lines

1
Central Venous Pressure and Central lines

• Big Lines for Big Problems

2
Challenging Knowledge

• Before starting this module Answer the following
  questions
• What sites are used to site a CVL?
• What is the normal CVP?
• What are the basic treatments for a CVP of -1cm
  of H20
• What are the essential items required to measure
  a CVP?

3
Learning Outcomes

• By the end of this module you should
• Be aware of factors which affect the CVP
• Recognise normal and abnormal CVP values
• Be able to set up the manometer system to measure
  a patients CVP
• Be able to measure a CVP and interpret the value
• Be aware of the initial management for high and
  low values

4
Factors affecting the CVP

• The central venous pressure reflects the right
  atrial pressure (RAP) and is similar to measuring
  the JVP clinically
• The factors which affect the CVP are-
• Systemic vasodilatation and hypovolaemia, which
  leads to reduced venous return in the vena cava
  and reduced RAP
• Right ventricular failure
• Tricuspid and Pulmonary valve disease
• Pulmonary hypertension
• Right ventricular dysfunction and pulmonary
  hypertension leads to raised right atrial
  pressure, as does tricuspid and pulmonary
  stenosis.

5
Central venous line (CVL)

• Indications for CVL
• Severe hypovolaemia requiring rapid infusion
• (although initial resuscitation may be peripheral
  through wide bore cannulae)
• Infusion of drugs which may cause peripheral
  problems e.g. vasoconstriction, phlebitis
• Measurement of central venous pressure (CVP)
• Confirmation of diagnosis e.g. Right heart
  failure
• Insertion of a pacing wire.
• Sites for insertion Internal jugular,
  subclavian and femoral vein Long lines are
  also inserted in the brachial vein.

6
How to measure the CVP using a manometer system

• The CVP system
• A bag of saline or dextrose reservoir
• Three way tap - connected to manometer,
  reservoir and patients CVL by tubing System is
  primed with fluid before starting
• Patient is lying supine if possible
• Manometer has spirit level at zero Zero point
  is aligned with right atrium using the mid
  axillary line / 4th ICS
• Measurements should be taken with the patient in
  the same position each time using the spirit
  level the zero point on the skin surface is
  marked for consistency of measurement

Patient positionedsupine on the bed
Three way tap
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How to measure the CVP using a manometer system

• Turn the three way tap OFF to the patient.
• Fill the manometer to the top from the reservoir
• Turn the three way tap OFF to the reservoir
• This means the column of fluid is supported only
  by the RAP / CV pressure
• The column will fall according to CVP
• The column swings with respiration -
  conventionally the level is taken as the mean.

Three way tap OFF to the patient allowing the
manometer to be filled
Three way tap OFF to the reservoir allowing the
CVP to be measured
8
Normal CVP measurements

• The normal CVP is between 5 10 cm of H2O (it
  increases 3 5 cm H2O when patient is being
  ventilated)
• In high dependency areas an electronic transducer
  is connected instead of the manometer system.
  This gives a continuous readout of CVP along with
  a display of the waveform. This may be measured
  in mmHg.
• (Note10 cmH20 7.5mmHg 1kPa)

9
CVP Reading Other clinical features Diagnosis Treatment
Low Tachycardia Low normal or hypotension Urine output oligo or anuria Hypovolaemia Fluid challenge until CVP within normal limits and treat underlying cause
Low ( may be normal or high due to venoconstriction) Tachycardia Signs of infectionPyrexiaVasodilatation is most common but severe sepsis maybe associated with constriction Sepsis Fluid resuscitation (if low) Antibiotics May require inotrope support
Normal due to venoconstriction Tachycardia Urine outputfalling below 30ml /hr Poor capillary refill Hypovolaemia Fluid challenge and treat underlying cause
High Dyspnoea with pulmonary crepitations Tachycardia with third heart sound Tender hepatomegaly Ascites Peripheral Oedema Heart failure Diuretics, GTN infusion, may require inotropes
Very High Venous congestion and dilatation of face and neck associated signs SVC obstruction Cardiac tamponade Tension pneumothorax Treat underlying cause
10
Case (1) How low can you go?

• A 32 year old woman with known alcohol associated
  liver disease presents with melaena. Initially
  she is haemodynamically stable and well perfused.
  She suddenly decompensates with fresh blood and
  clots being passed PR. Initial resuscitation with
  several litres of crystalloid and some colloid
  fails to bring her systolic BP back above 100 mm
  Hg. A CVP line is inserted and shows her CVP to
  be 1 cmH2O.
• (a) What is the likely diagnosis?
• (b) List your further management including
  investigations and medications

11
Case (2) CVP Pat pending

• A 31 year old man presents to AE with a 3 month
  history of night sweats and weight loss. On
  examination he is unwell, pyrexial and has
  several large cervical lymph nodes. He is noted
  to have poorly palpable radial pulse, a positive
  Kussmauls sign and poorly heard heart sounds.
  The SHO decides to site a CVP which is measured
  at 28 cm of H2O.
• (a) What is the likely underlying diagnosis?
• (b) What is the initial treatment?
• (c) How will you prove the diagnosis?

12
Case (3)

• A 48 year old poorly controlled Type 2 diabetic
  man is admitted from the Diabetes clinic with a
  deep, infected foot ulcer. His observations are
  pulse 120bpm, BP 70/40, CVP 6 cm of H20 and he
  is noted to be sweaty and vasodilated. Despite
  initial resuscitation with 3 litres of
  crystalloid in 4 hours, his BP and pulse fail to
  respond. He is electively ventilated and admitted
  to ITU where he is started on inotropes.
• What is the descriptive term given to this
  clinical state?
• List your further management?

13
Learning Outcomes

• At the end of this module you should
• Be aware of the factors affecting the CVP.
• Be able to set up a CVP manometer system.
• Be able to measure a CVP from a patient.
• Be able to interpret the result.
• Be able to institute initial management based on
  the result.