Central venous access

Question 1

What are the clinical application of carotid pulse

Answer 1

measuring pulse rate

Question 2

List the indications for central venous cannulation

Answer 2

Infusion of drugs
Irritant/vasoactive drugs
Long term administration
Total parenteral nutrition 
Inability to obtain peripheral access
ECMO - Extracorporeal membrane oxygenation: provide cardiorespiratory support when patient’s heart and lungs are unable to provide an adequate amount of gas exchange or perfusion to sustain life.
Vascath
Filtration, Dialysis
Rapid administration of large volumes of fluid

Question 3

What is a vascath

Answer 3

A Vas Cath is a specialised central venous catheter used in dialysis.

Question 4

Describe the cardiovascular indications for central venous cannulation

Answer 4

Cardiovascular monitoring
Central Venous Pressure
Central venous oxygen saturation
Cardiac output monitoring
Right atrial pressure
Right ventricular pressure
Pulmonary artery pressure

Using a pressure transducer

Question 5

What are the contraindications for the use of central venous cannulation

Answer 5

Absolute
Patient refusal
Local infection
Relative
Inability to lie flat
Clotting abnormalities
Thrombus in vein
(NOT for rapid administration of large volumes of fluid)

Question 6

List the insertion sites for central venous cannulation

Answer 6

Internal jugular vein
Subclavian vein
(Femoral vein)

Question 7

Outline the steps taken to prepare the procedure

Answer 7

Decide cannulation site based on patient and familiarity of operator with technique
Obtain consent (verbal/written)
Position patient for IJV or SV: head down (Trendelenburg), turn head to contralateral side; (supine for FV)
Attach monitoring ECG, BP, Sats
Use aseptic technique: scrub hands, put on mask, gown and sterile gloves.
Check equipment, attach 3-way taps, flush line
Clean and drape patient’s skin

Question 8

Outline the steps in the procedure itself

Answer 8

Identify landmarks: ultrasound > surface anatomy
Infiltrate local anaesthetic to skin and SC tissues (10mls of 1% lignocaine)
Insert cannula using a Modified Seldinger Technique needle/cannula - guidewire, cut skin, dilate vessel, thread central venous catheter.
Watch ECG at all times (for IJV or SV)
Never let go of the guidewire
Aspirate blood from all ports, re-flush with saline, prior to suturing catheter.
The correct position for internal jugular lines is usually 13-15cm to the skin
Post insertion CXR - check for line position, absence of pneumo/haemothorax.
Document consent, procedure performed and CXR findings in notes.

Question 9

What are the complications of central venous cannulation

Answer 9

Catheter in the wrong place
Pneumothorax, haemothorax, chylothorax
Arterial puncture
Nerve injury (recurrent laryngeal, phrenic, brachial plexus)
Tracheal injury

Question 10

What is meant by a chylothorax

Answer 10

Chylothorax is a rare condition in which lymphatic fluid leaks into the space between the lung and chest wall.

Question 11

What are the problems associated with having a catheter in a central vein

Answer 11

Problems with having a catheter in a central vein
Haemorrhage
Arrhythmia
Emboli: Thrombotic, Air
Infection: Local, Systemic
Valve damage, atrial or ventricular puncture, pulmonary artery rupture

Question 12

Essentially, what is the difference between a catheter and a cannula

Answer 12

Cannula is a short flexible tube which is introduced into a blood vessel, while Catheter is defined as a tube which is substantially longer than Intra Vascular Cannula for peripheral access to body