Subclavian Vein Catheterization Techniques

The technique is identical to that described above for internal jugular vein cannulation except for the puncture site. Two techniques, infraclavicular and supraclavicular, are described below and summarized in Table 38-7.

Table 38-7. Comparison of Subclavian Vein Cannulation Routes

Infraclavicular approach Supraclavicular approach Entry site Just inferior to the clavicle at the midclavicular line 1 cm lateral to the clavicular head of the sternocleidomastoid muscle, 1 cm posterior to the clavicle Needle orientation Keep as close to the coronal plane as possible Tip aimed 10 degrees anterior to the coronal plane Needle bevel and "J" wire directed (FIG) Medially and caudally Medially Aim toward Just posterior to the sternal notch Contralateral nipple, needle bisects angle formed by the clavicle and the clavicular head of the sternocleidomastoid muscle Distance from skin to subclavian vein 3–4 cm 2–3 cm

Infraclavicular Approach to the Subclavian Vein

The infraclavicular approach to the subclavian vein is most often used. It is commonly thought to be easier to perform and less likely to result in a pneumothorax than the supraclavicular approach, although data for this belief are lacking.¹⁷ Some physicians prefer not to use a finder needle for infraclavicular subclavian vein cannulation as there is no danger of penetrating the carotid artery. This also makes as few needle passes near the pleura as possible in order to decrease the risk of a pneumothorax. Estimate the distance from the skin puncture site to the superior vena cava (i.e., the manubriosternal junction).

Several different skin entry sites are described in the literature. Some feel that the preferred entry site is 1 cm caudal to the junction of the medial and middle thirds of the clavicle. The subclavian vein lies just posterior to the clavicle at this site. The first rib lies between the pleural dome and the subclavian vein. Direct the introducer needle just superior and posterior to the suprasternal notch while staying as close to the frontal (coronal) plane as possible. The needle and syringe should be parallel to the bed (Figure 38-14). Placing the nondominant index finger in the sternal notch will help to guide placement (Figure 38-14).

Some practitioners prefer to enter the skin inferior to the clavicle at the deltopectoral groove, or the point just lateral to the midclavicular line along the inferior surface of the clavicle. This is the point where the skin may be maximally depressed. Direct the introducer needle parallel to the bed and toward the sternal notch. This entry site may make it easier to keep the introducer needle in the coronal plane. The distance before entering the subclavian vein is longer than in the preceding approach and the protection offered by the first rib is lost.

One of the editors (R.R.S.) prefers to use a different landmark. Palpate the bony tubercle, or protrusion, on the inferior surface of the clavicle and approximately one-third to one-half the length of the clavicle from the sternoclavicular joint. The advantage of this site is that it is a definitive landmark and avoids approximating distances, as described for the other sites above. Insert the introducer needle parallel to the bed and aimed just posterior to the sternal notch.

The bevel of the introducer needle should be oriented caudally, as should the "J" in the guidewire. This position will allow the guidewire to enter the innominate vein and superior vena cava rather than being directed upward into the internal jugular vein or across to the contralateral subclavian vein (Figure 38-15). Once venous blood is aspirated, the Seldinger technique for catheter insertion is otherwise the same as previously described for internal jugular vein cannulation. Aspiration of bright red blood under pressure indicates subclavian artery puncture, which will be incompressible. Remove the introducer needle and observe the patient for signs of significant hemorrhage over the next several hours. Aspiration of air indicates penetration of the pleura. Observation with serial chest radiographs for at least the next 6 to 24 hours is essential to evaluate the size of the resulting pneumothorax.