2.3 IJV

The right internal jugular vein is the first site of choice for short-term central venous cannulation, although the subclavian route is preferred by many for longer-term central access. The internal jugular vein is readily accessible and the technique has a relatively low complication rate. The ability to cannulate the vessel is a core skill.

• The internal jugular vein originates at the jugular foramen in the skull (the foramen drains the sigmoid sinus) and is a continuation of the jugular bulb. • It follows a relatively straight course in the neck to terminate behind the sternoclavicular joint, where it joins the subclavian vein. • Throughout its course it lies with the carotid artery and the vagus nerve within the carotid sheath, but it changes position in relation to the artery, lying first posteriorly before moving laterally and then anterolaterally. • The vein is superficial in the upper part of the neck and then descends deep to the sternocleidomastoid muscle.

The structures through which a cannulating needle passes are skin and subcutaneous tissue, the platysma muscle, sternocleidomastoid (in the lower neck) and the loose fascia of the carotid sheath.

Anterior to the vein at the top of its course lie the internal carotid artery and the vagus nerve. Posterior to the vein (from above downwards) are the lateral part of C1, the prevertebral fascia and vertebral muscles, the cervical transverse processes, the sympathetic chain and, at the root of the neck, the dome of the pleura. On the left side, the jugular vein lies anterior to the thoracic duct. Medial to the vein are the carotid arteries (internal and common) and four cranial nerves: the ninth (glossopharyngeal, IX), the tenth (vagus, X), the eleventh (accessory, XI) and the twelfth (hypoglossal, XII).

the central venous pressure (CVP) gives information both about a patient’s volaemic status and about the function of the right ventricle

The CVP is the hydrostatic pressure generated by the blood within the right atrium (RA) or the great veins of the thorax. It provides an indication of volaemic status because the capacitance system, which includes all the large veins of the thorax, abdomen and proximal extremities, forms a large compliant reservoir for two-thirds of the total blood volume.

CVP measurements also provide an indication of right ventricular (RV) function. Any impairment of RV function will be reflected by the higher filling pressures that are needed to maintain the same stroke volume (SV).

The normal range is 0–8 mmHg, measured at the level of the tricuspid valve. The tip of the catheter should lie just above the right atrium in the superior vena cava. CVP measurements are sometimes recorded as negative values. Sustained mean negative values can occur only if the transducer has been placed above the level of the right atrium. Transient negative values may be recorded in conditions such as severe acute asthma in which partial respiratory obstruction generates high negative intrathoracic pressures which are transmitted to the central veins

CVP catheters are used for the monitoring of CVP, for the insertion of pulmonary artery catheters (much less commonly in current practice) and to provide access for haemofiltration and transvenous cardiac pacing. They also allow the administration of drugs that cannot be given peripherally, such as inotropes and cytotoxic agents, and the infusion of total parenteral nutrition. In massive air embolism they can be used to aspirate air from the right side of the heart, although few anaesthetists have ever used them for this purpose.

An example would be the high approach. A fine ‘seeking’ needle (25G or similar) is inserted at the level of the superior border of the thyroid cartilage (at about C4) and on the medial border of sternocleidomastoid. The needle is directed caudally at an angle of 30’ in the direction of the ipsilateral nipple. . The vein is usually quite superficial, although this will depend on the body habitus of the patient. Once the vein is located, the Seldinger technique (catheter over guidewire) can be used to establish definitive central access

These alternatives are the subclavian, femoral and the median cubital and basilic veins of the antecubital fossa. A peripheral long line can be inserted via the latter. This technique has few complications, but the catheter tip may fail to pass beyond the acute curve at the clavipectoral fascia and the catheter length means that fluid cannot be infused rapidly. The femoral vein is commonly overlaid by the superficial femoral artery and the variable anatomy means that femoral access can sometimes be difficult. The route is used commonly in children but is more of a last resort in adults, in whom the subclavian veins are usually a better alternative.

the right and left subclavian veins are relatively short, extending from the outer border of the first rib to the medial border of the scalenus anterior muscle. Here they unite with the internal jugular veins to form the brachiocephalic veins. The important relations are anteriorly – the clavicle; posteriorly – the subclavian artery; inferiorly – the dome of the pleura. The insertion point of the cannula is usually 1 cm below the clavicle at its midpoint, directed towards the suprasternal notch.

Complications: many of these can be minimized by the use of an ultrasound-guided needle. The National Institute of Clinical Excellence (NICE) report of September 2002 recommended the routine use of ultrasound for locating the internal jugular vein. The vessel is not always present, is not always located in the textbook anatomical position and is not always patent. Experienced has widened to the point at which ultrasound-guided cannulation is now routine, if not mandatory

• Carotid artery puncture or cannulation: the risk is reduced if the artery is palpated continuously throughout cannulation, and as for the preceding example is minimized by the use of ultrasound. • Pneumothorax (and haemothorax): this is less likely if a high approach is used which avoids the dome of the pleura. • Thoracic duct injury (chylothorax): the thoracic duct cannot be damaged if the left side is not used. Otherwise the risk is again minimized by using a high approach. • Intrapleural placement: here too the risk is attenuated by using a high approach which avoids the pleura. A check X-ray (which is mandatory following central venous cannulation) will prevent inadvertent intrapleural infusion. • Air embolism: positioning the patient head down during insertion (and removal) decreases the risk. 6.Cardiac arrhythmias: these may occur should the guidewire or catheter reach the heart.

central line infection can be disastrous. Significant infection is said to occur in around 12% of insertions, although some degree of bacterial colonization, both intra- and extra-luminal, probably occurs in every placement. Both external and endoluminal surfaces of any intravascular catheter rapidly become coated with plasma proteins, which in turn become colonized by bacteria which migrate down from the skin. This process occurs within hours. Once a threshold number of organisms is reached, symptomatic bacteraemia will follow. This process usually takes 3 to 4 days, and the commonest organisms implicated are coagulase-negative staphylococci and staphylococcus aureus (together these account for around 60% of the total). Other species include enterococci and pseudomonas. Catheter-related sepsis has a mortality that has been reported as high as 25%. The risks are reduced by scrupulous aseptic technique as well as meticulous aftercare. The insertion site is also significant: subclavian CVCs have the lowest rates of infection.