Subclavian Cannulation. Infraclavicular Approach.

   

 The subclavian vein, offers an alternative to the internal jugular vein for central venous access. It may be associated with fewer infectious complications than the internal jugular vein, and will remain accessible after localized thrombosis of the internal jugular vein. 

    Well-designed studies comparing the internal jugular and subclavian approaches are sparse. Review of multiple nonrandomized studies suggests the arterial puncture is more frequent with the internal jugular approach, catheter malposition is more frequent with the subclavian approach, and the incidences of pneumothorax, hemothorax, and thrombosis are equivalent.

    The anatomic landmark approach to subclavian cannulation remains the standard of care and is our preferred and routine approach to this vessel. However, the enhanced safety of ultrasound in the internal jugular position increases interest in sonographically-assisted cannulation of the axillary vein as an alternative, but any advantage of this technique over landmark-guided subclavian cannulation remains unproven.

    An infraclavicular approach to the subclavian vein is preferred by the authors. The operator stands on the side to be cannulated. A right-handed operator will find a position partially turned toward the patient’s feet most comfortable for right-sided cannulation and a position turned partially toward the patient’s head most comfortable for left-sided cannulation. The positions can be reversed for left-handed operators. The patient should be placed in the Trendelenburg position to maximize venous filling and minimize risk of air embolus; the head and neck position should be neutral.

    The goal of subclavian venipuncture is to pass a needle inferior to the clavicle and superior to the first rib to access the subclavian vein as it courses over the first rib. The appropriate course for the needle passes immediately beneath the junction of the medial one-third and lateral two-thirds of the clavicle. This junction, ie, the “break” of the clavicle, is the point at which the anterior convexity of the medial clavicle transitions into an anterior concavity laterally.

    The appropriate point for cutaneous puncture lies 1–2 cm inferior and lateral to the clavicular transition point. Cutaneous puncture at this point facilitates passage of the needle inferior to the clavicle. A cutaneous puncture site closer to the clavicle creates difficulty maneuvering the needle beneath the clavicle. More medial cannulation may be impeded by calcification of the costoclavicular ligament. As the needle is advanced, it must remain absolutely parallel to the floor; if the needle is directed posteriorly to negotiate the clavicle, the risk of pneumothorax is greatly increased. Only gentle pressure from the operator’s nondominant thumb is necessary to depress the needle in a flat coronal plane beneath the clavicle if the correct cutaneous puncture site is chosen.

    As the needle is advanced from the cutaneous puncture site to a point beneath the clavicular transition point, its tip should be aimed just above the tip of the operator’s nondominant index finger placed in the sternal notch. The needle is advanced along this course passing through the subclavius muscle until the subclavian vein is accessed.

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