Makindo Medical Notes.com

Ultrasound 2D guidance is recommended for central venous line insertion in elective and emergency situation to allow knowledge of the local vascular anatomy. It significantly decreases the failure rate, complication rate, and number of attempts required for successful access

Precautions

• Only competent staff (or training staff supervised by competent staff) should perform this procedure

Indication

• Central venous pressure measurement
• Measure Central venous gas measurements: a fluid resuscitation aid
• When peripheral venous access is not possible
• For drug administration e.g. inotropes, antiarrhythmics, chaemotherapy or Total parenteral nutrition
• Haemodialysis, plasmapheresis, temporary cardiac pacing

Contraindications

• Agitated, uncooperative patient
• Uncorrected bleeding diathesis or anticoagulated or post thrombolysis
• Skin infection or burn over the puncture site
• Pneumothorax or haemothorax on the opposite side or the presence of only one functioning lung.
• Some of these are relative and if clinically urgent then senior help should be requested

Choice of Vascular access sites

• Depends on the indications, risk of complications and expertise of the doctor. Central veins are often deep and have to be located without the aid of direct vision. This is associated with damage to nearby structures, especially in the hands of an inexperienced operator.
• Successful catheterization by either the internal jugular or the subclavian route, therefore, relies on a thorough understanding of the anatomy of the neck and the use of 2D ultrasound.
• Internal jugular vein is located at the apex of the triangle formed by the heads of the sternocleidomastoid muscle and the clavicle.
• Subclavian vein crosses under the clavicle just medial to the midclavicular point.

Internal Jugular Vein

Compressible vein if bleeding. US is useful. Arterial puncture is possible. Risk of pneumothorax or haemothorax. Need to place the patient in a head-down position which can exacerbate cardiac and respiratory failure.

Subclavian Vein

Not Compressible vein if bleeding. US can be useful. Arterial puncture is possible. Risk of pneumothorax or haemothorax. Need to place a patient in head-down position which can exacerbate cardiac and respiratory failure.

Femoral Vein

Very compressible vein if bleeding. US is less useful. Anatomy NAVY - the Nerve/Artery/Vein and Y fronts! so vein is most medial structure. Arterial puncture is possible. Risk of pneumothorax or haemothorax. Place person in head-up position which can help cardiac and respiratory failure. Higher infection risk.

Equipment

• Adult CV catheters for subclavian or internal jugular lines are commonly 20 cm in length although

Technique

• Explain and obtain informed consent. The patient is positioned in the Trendelenburg position (feet up, head down to increase vein size) for internal jugular vein or subclavian vein CVC insertion. For femoral vein, CVC the supine position is adopted.
• Use a full sterile technique (sterile gown and gloves, mask, cap with ultrasound probe in sterile sheath) must be used. The area should be cleaned in a sterile fashion using an appropriate disinfectant, followed by sterile draping.
• Use 1-2% Lidocaine/Lignocaine used to anaesthetise the venepuncture area as well as the suture area. The artery is usually medial to the vein, smaller and pulsatile and unlike the vein, is not compressible.
• Advanced the needle under Ultrasound while applying negative pressure to the syringe until a flash of blood is visualized.
• Use the Seldinger technique (guidewire through the needle which is then withdrawn to leave the guidewire only) is then used to insert the catheter after which a chest radiograph is required to confirm the position and exclude a pneumothorax. Never let go of the guidewire.

Complications

• Malposition of the catheter
• Air emboli
• Bleeding and Haematoma
• Catheter embolism
• Arterial puncture and Thrombosis
• Pneumothorax and Haemothorax
• Cardiac tamponade
• Sepsis
• Cardiac arrhythmias

Central Venous Pressure

• This is expressed in cm H₂O above a point level with the right atrium. The normal value is 0-8 cmH₂O and is measured with the patient lying flat.
• A volume challenge of 250 mls of colloid over 15 minutes: an increase in CVP of less than 5 cm H₂O (or 3 mmHg), or one that is not sustained for more than 10 minutes suggests hypovolaemia.
• Serial readings are much more useful than a single reading. The presence of anatomical variants such as tricuspid regurgitation which may alter the baseline CVP reading of the patient must be taken into account.