Subclavian Central Venous Catheterization:
Central venous lines are essential tools in the care of complicated patients, both on inpatient wards and in the emergency department and intensive care unit. They may provide access for blood draws, facilitate central administration of fluids and medications, and allow direct measurement of cardiac filling pressure.
Unfortunately, central lines are associated with serious complications, including nosocomial bloodstream infections. Recent data suggest that of the more than 200,000 such infections each year, 90% are due to central lines.1 One can minimize patient risk by practicing proper sterile technique during line insertion, maintaining adequate occlusive dressings, and removing all unnecessary lines as soon as possible.
The three main approaches used to place central lines are the internal jugular, subclavian, and femoral.
As the subclavian vein crosses the first rib, it lies posterior to the junction between the medial third and lateral two thirds of the clavicle. The vein has a diameter of 1 to 2 cm. Connective tissue fixes the subclavian to the first rib and clavicle, and thus the vein does not collapse in cases of hypovolemia or cardiac arrest. The subclavian arteries are located posterior to the veins and are separated from them by the scalene muscles.
The domes of the pleurae of the lungs may extend above the first rib on the left but rarely extend this far on the right, and thus the right side is often preferred for line insertion.
Insertion on the right also avoids the risk of damage to the thoracic duct, which is located near the junction of the left subclavian and left internal jugular.
Clinical Pearls: If you are anticipating the use of a transvenous pacemaker or pulmonary artery catheter, you should use either the left subclavian vein or the right internal jugular vein. These approaches align the catheter trajectory with the SVC and right atrium.
With your nondominant hand, place your thumb over the bend in the clavicle and your index finger in the suprasternal notch.
Insert the 18-gauge introducer needle 1 cm inferior to the junction of the middle and proximal third of the clavicle while aiming slightly cephalad toward your index finger in the suprasternal notch.
Maintain a 5- to 10-degree angle relative to the chest wall.
Insert the needle with the bevel directed inferiorly.
This bevel orientation facilitates proper advancement of the guidewire into the SVC instead of up the internal jugular vein.
Slowly advance the needle until it contacts the clavicle.
Using the thumb on your nondominant hand, slowly push posteriorly on the needle to help guide it toward the inferior surface of the clavicle.
Do not change the angle of the needle relative to the chest wall, and keep the angle of the needle parallel to the floor.
With the needle still almost parallel to the floor, carefully advance it under the clavicle while pulling back on the plunger and aiming for your index finger in the suprasternal notch.
Advance the needle until a flash of freely flowing dark venous blood (usually approximately 3 to 4 cm deep) is seen.
Clinical Pearls: If air is aspirated, the pleura has been violated and the patient should be evaluated for pneumothorax. Any subsequent attempts at central access should occur on the same side to avoid bilateral pneumothorax.
If no blood is encountered while inserting the introducer needle, slowly withdraw the needle while continuing to aspirate (occasionally, you will enter the vein as you withdraw). If there is no blood return, withdraw the needle to just posterior to the clavicle, aim more cephalad, and try again. If access is not achieved, completely remove the needle and flush it before redirecting it slightly more cephalad.
Identify the junction of the clavicular head of the SCM and the clavicle.
Insert the 18-gauge introducer needle 1 cm lateral to the SCM and 1 cm superior and posterior to the clavicle.
Aim toward the contralateral nipple, bisecting the angle of the SCM and the clavicle.
Insert the needle with the bevel directed medially.
Carefully advance the needle while pulling back on the plunger until a flash of freely flowing dark venous blood (usually approximately 2 to 3 cm deep) is seen