2.3 IJV Flashcards
Commentary
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 anatomy of the internal jugular vein
- 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.
Structures when cannulating IJV
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.
relations
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).
Supplementary and Clinical Information
Principle:
the central venous pressure (CVP) gives information
both about a patient’s volaemic status and
about the function of the right ventricle
Intravascular volume
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.
Right ventricular function
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).
Normal values:
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
Indications:
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.
Technique(s) for Insertion of a Central Venous Catheter (CVC)
Anatomical
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
There are alternative sites, should internal jugular cannulation be impossible (for
example, in major head and neck surgery or in patients with neck and facial burns).
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.
Anatomy of the subclavian veins:
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 Associated with the Technique
Following is a compilation of the most common; the literature is full of others which
range from spinal accessory nerve injury to cardiac tamponade.
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
Complications
- 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.
Infection:
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.
