Central venous catheterisation

Central venous catheterisation

Central venous catheterisation refers to the introduction of PVC Teflon or other type of catheter into a central vein. This may be the superior vena cava or the inferior vena cava usually via the subclavian or the internal jugular vein.

Central venous pressure (CVP) is the pressure in the great (or central veins) close to the right atrium and is measured through a central venous catheter. It reflects the pressure under which blood is returned to the heart (preload) and the competence of the right atrium to accept and deliver blood.

The normal CVP is 1-5mmHg or 1-7cm H20 with the zero at mid -axillary line and the patient lying flat and breathing quietly. If the patient is ventilated the CVP is measured with the patient remaining on the ventilator.

Indications

· guide to fluid volume replacement

· administration of total parental nutrition or other hypertonic solutions, which are irritating to peripheral veins

· administration of inotropic agents

· long term antibiotic therapy

· emergency rescucitation

·

routinely post cardiac surgery

CVC line placement

Insertion

Equipment:Sterile dressing tray, sterile gloves and gown for medical officer, 1% Xylocaine, 10ml syringe and needles, heparinized saline, persist plus swabs, tegaderm dressing, suture 2/0 silk, blue incontinent sheet to protect bed, percutaneous sheath Introducer kit, CVP set multi-lumen (Arrow), single pressure transducer set or triples lumen pressure transducer set (if arterial line being inserted as well), N/Saline 500mls and heparin 500units for flush bag and Fenwell pressure bag.

· explain the procedure to the patient prior to insertion

· position the patient flat and head down, with pillows removed to increase venous pressure and prevent air embolism, place a blue sheet under patient's shoulders

· assist the medical officer in gowning and gloving

· MO cleans the site with Persist Plus, drapes and infiltrates with local anaesthetic

· MO inserts CVC using full aseptic approach and Seldinger technique

· the CVC is sutured in place

· haemodynamic monitoring line is attached

· the CVC is secured with a Tegaderm dressing

· do not commence infusions until position of the CVC is confirmed on CxR

· chest x-ray is performed to confirm position of catheter tip and to exclude pneumothorax

· document the insertion site and date on B4 flow chart.

Measuring CVP via transducer

· position patient flat, ensure bed is level and transducer is level with mid axillary point

· flush the line to ensure correct trace is visible

· zero the transducer by turning the three-way stopcock off to the patient, and open to air. Press CVP zero key on physiological monitor console. Hold for three seconds until 0 pressure seen on digital display. Replace the bung and open stopcock to patient.

A mean CVP will displayed on the monitor. The normal CVP is 5-10mmHg. Measure CVP hourly until stable then four hourly thereafter.

Administering medications via the CVC

· check compatibility prior to administration

· swab injection port with alcohol wipe, allow to dry prior to administration

· inotropes must be infused in a dedicated port to avoid inadvertent boluses (no three way taps to be placed on these infusions)

· all patients must have one lumen available for administration of emergency drugs.

· always flush lumen with 5-10 cc of normal saline post administration of ‘prn’ medications

· label infusions with appropriate stickers

Complications

· pneumothorax/haemothorax

· air embolism

· blocked lumens occur if lumens not used. Please flush TDS with heparinized saline and aspirate and flush lumens when discontinuing infusions for longer then 1 hour

· thrombosis of the subclavian vein (evidenced by peripheral oedema of arm on the side of cannulation)

· arrhythmias may occur if the catheter is too long and enters the right ventricle

· malposition of the catheter in other than central vein such as up the neck into internal jugular vein, the heart or pleural cavity

· infection ® contamination may result in septicemia

· catheter embolus or knotting

· microshock

Management

Avoid contamination of the system when changing infusions and administering medications.

· IV drip sets are changed every seven days and when necessary. The date is documented in B4 flow chart.

· IV propofol giving set must be changed 12 hourly

· if clinically indicated (signs of localized infection) CVC must be removed and tip sent for culture

· if the CVC is accidentally disconnected from the giving set, place patient head down, connect syringe to hub and call for assistance (in non-ventilated patients only).

· check system each shift, including re-zeroing transducer

· all lines should be correctly labelled

Removal

· explain the procedure to the patient

· wash hands thoroughly

· position the patient flat and head down, remove dressing and suture. Ask patient to take a deep breath and hold, remove catheter (in non-ventilated patients only).

· cover the site with sterile gauze and Tegaderm dressing for 24 hours

· the catheter tip should be sent to the lab if the site is inflamed, for culture and sensitivity