Finding the Vein

(Anatomy specimen photographs courtesy of the Department of Anatomy, University of Hong Kong, with grateful thanks)

Internal Jugular Vein (IJV)

The IJV emerges from the base of the skull through the jugular foramen and runs through the neck, parallel to the carotid artery, to join the subclavian vein (SV) behind the sternal end of the clavicle. The junction of the IJV and SV forms the brachiocephalic vein (aka. innominate vein), which flows into the superior vena cava (SVC), and from there into the right atrium (RA).

The IJV initially runs posterior to the carotid artery, then laterally, and then anterolaterally. It is a superficial structure, particularly in the upper neck, and in the majority of patients can be palpated directly.

A number of techniques have been described to locate the needle insertion point for IJV cannulation. These include the so-called 'high' and 'low' approaches depending on the relative distance of the needle insertion point from the clavicle - techniques in which the needle is inserted well above the clavicle constitute a 'high' approach. High approaches to IJV cannulation are often preferred as they are associated with a lower rate of pneumothorax. Three commonly used techniques for finding the IJV are described below. This list is by no means exhaustive - many variations of these techniques have been described.

1. Midpoint between sternal notch and mastoid process ('high' approach)

        

The patient should be positioned without a pillow, arms by the sides and the head turned to the opposite side than that being cannulated, with the head of the bed tilted down 15°-20°. A large area around the insertion site should be cleaned with the skin preparation used in your hospital (this area should include the landmarks to be used i.e. the mastoid process and the sternal notch) and the surrounding area is then covered with sterile drapes.

Following draping of the area find the mid point between the sternal notch and mastoid process using your fingers as protractors as shown in the following picture. Please note that in this picture the drapes have been removed and are not shown so that the position of the fingers can be easily seen. For right IJV cannulation, the little finger of the left hand is placed in the sternal notch, the little finger of the right hand is placed on the (right) mastoid process and the two index fingers indicate the midpoint. The hand positions are reversed for left IJV cannulation.

        

The pulsation of the carotid artery should be felt beneath the index fingers at the midpoint. The needle insertion point is just lateral to this pulsation. Insert the needle at 45° to the skin in the direction of the ipselateral nipple, maintaining slight negative pressure on the syringe until the vein is entered, at which point blood will flow back into the syringe. In the majority of cases the IJV will be reached at a depth of approximately 2-3 cm from the skin (deeper in patients with increased subcutaneous tissue!)

2. Apex of triangle formed by 2 heads of sternocleidomastoid muscle ('high' approach)

The patient should be positioned and the procedure performed under sterile conditions as described above.

Identify the apex of the triangle formed by the two heads of the sternocleidomastoid muscle and the clavicle. (NB. The hand positions shown in the photograph below are not relevant to this technique)

        

The needle is inserted at the apex of the triangle between the two heads of the sternocleidomastoid muscle, at a 45° angle to the skin in the direction of the ipselateral nipple. As before negative pressure should be applied to the syringe and the needle should enter the vein at a depth approximately 2-3 cm from the skin.

3. Ballot vein directly (superficial)

The patient should be positioned and the procedure performed under sterile conditions as described above.

The IJV is a superficial structure and in the majority of non-obese patients can be balloted directly. It is useful to first gently palpate the patient's thyroid cartilage, and then just lateral to this, the carotid artery. The IJV lies just lateral to the artery, is non-pulsatile and has a similar 'spongy' feel to peripheral veins. The needle should be inserted at the point where the vein can be palpated, again at a 45° angle to the skin in the direction of the ipselateral nipple as described above.

4. Central low approach

The patient should be positioned and the procedure performed under sterile conditions as described above.

Identify the triangle formed by the two heads of the sternocleidomastoid muscle and the clavicle. (NB. The hand positions shown in the photograph below are not relevant to this technique)

        

The needle is inserted at the centre point of this triangle at a 30° angle to the skin in a caudal direction. As before the needle is advanced whilst negative pressure on the syringe is maintained so that when the needle enters the vein the syringe will fill with blood. Care should be taken not to insert the needle too deeply as this will increase the risk of causing a pneumothorax - again the IJV should be located within a few centimeters depth from the skin. If the vein is not entered initially, from the same insertion point redirect the needle 5 -10° laterally and try again.

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Subclavian Vein (SV)

The subclavian vein is the continuation of the axillary vein. It begins at the lower border of the 1st rib and initially arches upwards across the rib, before angling medially and downwards to join with the internal jugular vein behind the sternoclavicular joint. For much of its course it therefore lies just under the clavicle. Following the merger of the subclavian vein with the internal jugular vein, it then continues its course as the brachiocephalic vein which turns towards the mediastinum joining with its contralateral counterpart to form the superior vena cava.

A number of approaches to the subclavian vein, both supraclavicular and infraclavicular, have been described. However the infraclavicular approaches appear to be more popular.

1. Midclavicular approach

The patient should be positioned head down and the procedure performed under sterile conditions as described for IJV cannulation above.

In adults the needle should be inserted 1 cm below the midpoint of the lower border of the clavicle. Keeping the needle close to the posterior border of the clavicle and parallel to the coronal plane, it should be advanced in the direction of the suprasternal notch maintaining negative pressure on the syringe until the vein is entered and blood is therefore aspirated. You may find it helpful to place a finger tip in the suprasternal notch to act as a target.

2. Alternative infraclavicular approaches

i) Insert the needle 1 cm below the lower border of the clavicle at the junction of the middle and lateral thirds of the clavicle (ie. 2/3 along the clavicle from the midline)

OR

ii) Insert the needle just below the lower border of the clavicle at the junction of the medial and middle thirds of the clavicle (ie. 1/3 along the clavicle from the midline)

Then advance the needle and syringe towards the suprasternal notch as described above.

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Femoral Vein

The femoral vein runs alongside the femoral artery in the thigh and drains into the external iliac vein at the level of the inguinal ligament. It lies medial to the femoral artery in the femoral triangle (the femoral nerve lies lateral to the femoral artery here). Superficial and deep fascial layers of variable thickness separate the femoral vein from the skin.

The patient should be positioned supine and the procedure performed under sterile conditions as described above.

Feel for the femoral artery in the groin at the midinguinal point (midway between pubic symphysis and anterior superior iliac spine – in line with midclavicular line). The femoral vein lies 1cm below and 1 cm medial to artery at this point. Insert the needle at this point at an angle of 20-30° to the skin, and advance in a cephalad direction maintaining negative pressure on the syringe until the vein is entered and blood is aspirated. In obese patients it may be beneficial to insert needle in line with but a few centimeters distal to the above insertion point again advancing cephalad at an angle of 20-30° to the skin, as this may allow you to enter the vein at a less acute angle than would otherwise be necessary and make for easier placement of the catheter.

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External Jugular Vein (EJV)

The external jugular vein (EJV) runs through the neck from the angle of the mandible to join with the subclavian vein behind the middle of the clavicle, crossing the sternocleidomastoid muscle obliquely en route. It is variable in size and possesses valves and, being a superficial structure, is usually either visible or easily ballotable– if you can't see it or easily feel it don't use it!

The patient should be positioned head down and the procedure performed under sterile conditions as described for IJV cannulation above.

Insert the needle in the line of the vein where it is most easily seen or palpated. The higher the cannulation above the clavicle the lower the risk of causing pneumothorax.

Difficulties may be encountered when threading the catheter into the vein due to the vein's potentially tortuous track and the presence of venous valves. Injecting fluid through the catheter or twisting the catheter as it is advanced may help. However do not force the catheter forward if high resistance is encountered.

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Antecubital Veins

Blood from the arm drains via two interconnecting veins – the basilica and the cephalic. There is a lot of individual variation in the anatomy of these veins, but basically the basilic vein runs medially and becomes the axillary vein on entering the axilla, wheareas the cephalic vein runs laterally and joins the axillary vein as it passes beneath the clavicle. Just before joining the axillary vein, the cephalic vein turns sharply almost making a right angle in its course, and it can therefore be difficult to thread a cannula past this point. The cephalic and basilic veins are joined by the median cubital vein at the elbow.

When using the antecubital approach for CVP catheterization generally the catheter through needle/cannula approach is used. The patient should be positioned supine and the procedure performed under sterile conditions.

A tourniquet is placed on the upper arm to distend the veins, and the largest and most easily palpable (preferably medial) vein is punctured as for a peripheral cannulation. The catheter is threaded a short distance through the cannula, the tourniquet is then removed and the catheter steadily advanced until its tip is likely to have reached the SVC. The guide wire is then removed from inside the catheter and, since it is the same length as the catheter it can then be used to check the catheter position. The guide wire is placed on the patient's chest and along the arm with the guide wire tip at the level of the SVC and the distal end near the puncture site. The catheter can then be withdrawn so that its distal end is level with the distal end of the guide wire. The catheter tip should therefore be level with the SVC.

If the catheter cannot be advanced into the vein due to an obstruction it should not be forced.

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