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Subclavian vein catheterization is associated with failure and complications because of injury to the nearby lung and subclavian artery. Its position, sandwiched between the clavicle and the first rib, makes sonographic imaging difficult. The medially pointed sonography probe makes it difficult to align the needle as well as image the entire needle. The axillary vein lies outside of the thoracic cage and can be easily imaged in its longitudinal view along with the entire needle, guidewire, dilator, and catheter in real-time. All described techniques of venous access using sonography have used transverse images of veins, and the needle is not completely visualized. Five cases of axillary vein catheterization using longitudinal section images of the vein, and following the needle, guidewire, and line with real-time sonography, are described. The use of longer puncture needles and introducer sheaths is suggested. A larger study is required to assess the potential of this technique. IMPLICATIONS: Axillary vein catheterization using real-time sonography provides an image of a puncturing needle and axillary vein simultaneously, preventing lung, arterial, and nerve injury.
Central venous access is often obtained through the subclavian vein. This technique is based on landmarks and fails in 8%19% of cases (1). An editorial by Haire and Lieberman (2) in the New England Journal of Medicine stressed the need for safer approaches to central venous access in the arm or the neck. The axillary vein starts at the axillary fold and becomes the subclavian vein at the lateral border of the first rib. This vein lies entirely outside the thoracic cage. Through cannulation of the axillary vein, complications such as pneumothorax, mediastinal hematoma, hemothorax, and tracheal injury may theoretically be avoided (35). Several researchers have performed axillary vein catheterization based on landmarks, with entry through pectoral muscles and the armpit (611). To improve the success of this technique, Schregel et al. (12) used Doppler to mark the vein on the skin surface. Galloway and Bodenham (13) performed a study on ultrasonographic imaging of the axillary vein and Nash et al. (14) used sonography to place pacemaker electrodes through the subclavian vein using transverse images of the vein. Real-time imaging of the axillary vein and the needle used to catheterize it are important requirements for preventing complications. The clavicle limits proper imaging of the subclavian vein and the advancing needle tip by blocking the ultrasound beam. All techniques of ultrasound-guided venous cannulation described in the literature have imaged veins in transverse section, with the needle approaching the beam at an angle. Because the needle crosses the ultrasound beam at one point only, it is imaged as a small dot. In many instances the needle is never imaged, and only indirect evidence of vessel compression may be seen. Although this may work well for superficial veins such as the internal jugular, it may not be safe for deeper veins. In the technique described below, the vein was imaged in longitudinal view and the needle or lines were kept under the ultrasound beam at all times, allowing their continuous imaging during all maneuvers. Five cases of axillary vein cannulation via an anterior approach through the pectoral muscles using ultrasound guidance are presented in this report.
The patients arm is abducted to 90° to straighten the axillary vein. A longitudinal image of the vein is obtained with a 4- to 7-MHz Sonosite 180® C 11 probe (Sonosite, Bothell, WA) (Figs. 1 and 2). After making sure the vessel being imaged is an axillary vein and not an artery, the position of the probe is outlined with a skin marker. The skin is prepared with Betadine and draped. The ultrasound transducer is draped in a sterile sheath (Microtek Medical, Columbus, MS) or sterile latex cover and the needle is positioned under the middle of the probe so that it will stay under the ultrasound beam at all times while it is advanced. Once the needle touches the anterior surface of the vein, a short, sharp, jabbing motion toward the center of the vein, followed by a quick stop, is used to puncture the anterior wall. Slow movement will collapse both walls and the needle will completely traverse the vein. Intravascular placement is confirmed by aspirating blood. If the needle is not in the middle of the vein, or is advanced too slowly, the vessel may slip to one side. The needle is repositioned by bringing its tip to the most anterior part of the vein; the jabbing motion is repeated until the vein is entered. The angle of the needle to the skin is decreased, and it is advanced a few millimeters. The axillary artery and its surrounding nerves are carefully avoided. A guidewire is introduced, and if excessive resistance is met, its advance in the vein is monitored under real-time imaging. Forcing the guidewire in such situations leads to its coiling at a venous valve. The vein should be scanned and the guidewire withdrawn slightly to unloop and advance it under imaging. Rotating the guidewire by 90° may be helpful. The catheter is then inserted using the standard Seldinger technique. The dilator should be carefully advanced using to-and-fro rotations and checking that the guidewire is moving freely. It is easy to create a false track through thick pectoral muscles; in this case, the guidewire does not move freely. When the guidewire is withdrawn, a kink or sharp bend is seen. The dilator can be advanced into the vein, as hematoma is unlikely because of low venous pressure, unlike in arteries. The introducer sheath is left in situ and the dilator is withdrawn. Care should be taken to puncture the vein a few inches lateral to the rib cage, and the course of the needle through the pectoral muscles should be such that it enters the vein at an acute angle. If the needle enters the vein at a larger angle, softer sheaths may kink after the dilator is removed.
Case 1 A 60-yr-old man, status postlaryngectomy, bilateral radical neck dissection, and tracheostomy, with a severely decreased ejection fraction and a left ventricular aneurysm containing thrombus, presented for removal of a recurrent tumor in the neck. He had had a left pectoral flap graft in the past and the donor site was covered with split-thickness skin grafts. He underwent a 6-h reexploration of the neck, with peripheral venous lines and arterial blood pressure monitoring. A central venous line was not attempted because only the right subclavian vein was available and to avoid the risk of pneumothorax in an extremely sick patient. The surgery proceeded uneventfully and the patient was brought to the postanesthesia care unit. He continued to be tachycardic despite sedation and good pain control, and urine output decreased. It was decided to monitor central venous pressure for judicious fluid administration. Both internal jugulars had been removed in a previous bilateral radical neck dissection and the left axillary and subclavian veins had split-thickness graft over the clavipectoral fascia. A triple-lumen catheter was placed in the right axillary vein under imaging. Fluid therapy was guided with central venous pressure and the patients tachycardia improved after a few fluid boluses.
Case 2
Case 3 A 40-yr-old woman with a history of human immunodeficiency virus, acquired immunodeficiency syndrome, hepatitis C and B, severe pulmonary hypertension, and IV drug abuse, was scheduled for removal of an infected hip prosthesis. She had no suitable peripheral venous access because of IV drug abuse and repeated hospitalizations. She became uncooperative after a few attempts to start a peripheral line. She refused an IV line in her neck because of discomfort and inconvenience during previous hospitalizations. Subclavian catheters had been placed during several previous admissions because of poor venous access. An 8.5F sheath was placed in the left axillary vein under real-time sonography and a PA catheter was inserted successfully before anesthesia.
Case 4
Case 5
Spracklen et al. (6) described a technique of catheterizing the axillary vein through the armpit in 1967. Their technique is dependent on palpation and landmarks, and failed in 6% of cases. Pain and paresthesias were experienced by 20% of their patients because of injury of ulnar or medial cutaneous nerves of the arm. The close proximity of the axillary vein, artery, and several nerves creates the potential for nerve injuries. The vein is punctured far laterally, and more valves are encountered. Norwood et al. (15) observed a frequent rate of infection of axillary artery catheters inserted through the armpit, and similar results may be expected for venous lines through the axilla. Nickalls (10) described axillary vein cannulation through pectoral muscles using landmarks in 14 patients, with 7% failure. Taylor and Yellowlees (11) performed a modified Nickalls technique in 102 patients, with failure in 3.9%, arterial puncture in 4.9%, transient paresthesias in 2%, and pneumothorax in 1%. The technique of Taylor and Yellowlees is based on landmarks, and does not take anatomical variations into account. Schregel et al. (12) used Doppler to map the axillary vein and mark it on the skin, and then introduced the needle blindly. They failed in 14% and punctured the artery in 8%. Schregel et al. could not puncture the vein in 4% of cases despite good Doppler signals. (Simply marking skin in one plane does not guarantee that the needle will reach the vein, because the axillary vein tends to slip to one side when the needle is pushed.) Galloway and Bodenham (13) imaged the axillary vein in 93% of their 50 patients. In the authors experience, there was no difficulty in visualizing the axillary vein in >2000 patients while administering ultrasound-guided infraclavicular brachial blocks. Nash et al. (14) used Site-Rite® to image the subclavian vein and introduced pacing electrodes in 70 patients with 80% success. They reported pneumothorax in one, and failure to negotiate the guidewire in many of their patients despite successful punctures. They imaged the vein transversely and the needle was not seen through most of its course. Guidewire and catheter insertion were not observed in real-time. Imaging a vein in longitudinal section allows observation of guidewire advance, and if the wire is caught in a valve, it can be manipulated to cross the valve. Imaging a vein longitudinally and observing the entire procedure in real-time overcomes these drawbacks and improves safety and success. Mansfield et al. (1) found no benefit of ultrasound over the traditional techniques. In their study, however, ultrasound was used only to facilitate measurement of the depth, caliber, and patency of the subclavian vein. They did not use real-time imaging. The clavicle covers the subclavian anteriorly, making its imaging difficult. The axillary vein, however, is easily imaged and the advancing needle can be visualized until its entry into the vein. The subclavian vein transverses the dome of the lung, hence the traditional approach based on landmarks may be complicated by pneumothorax (1.5%). The subclavian artery lies adjacent to the vein and is often punctured (3.7%), leading to mediastinal hematoma (0.6%) or hemothorax (1,2). Subclavian vein cannulation fails in 8% of patients with no previous surgery and body mass index <30. In obese patients, the failure rate is as much as 20%, and in the presence of obesity, radiation, previous cannulation, and operator inexperience, the failure rate may be even more frequent. Many others have found sonographic guidance to be a useful aid for central venous access (35). Gualtieri et al. (4) performed 52 subclavian cannulations in a randomized study in 33 patients with and without ultrasound; the success rate for inexperienced operators was 92% with ultrasound and 44% without. Their technique was different from that of the authors, because they imaged the subclavian vein transversely through the window between the clavicle and the first rib by pointing their probe medially, and they used a needle guide to stabilize the needle. They could not use this technique in one case in which the vein was anterior to the artery. In their technique, the needle crosses the plane of the ultrasound beam at an angle and may or may not be seen at all depths and all times, unlike my approach. Moreover, it appears only as a small speck in the image. Gualtieri et al. (4) observed that 27% of their patients had anatomical variations. A comparison of subclavian and axillary vein cannulation techniques is shown in Table 1. This technique can be a useful rescue technique when other modalities of subclavian catheterization have failed. The author has used this technique with different types of catheters and settings: triple lumen in Case 1; an introducer sheath and PA catheter in asleep and awake patients in Cases 2 and 3, respectively; an introducer sheath in an awake patient in Case 4. The patient in Case 5 had a double-lumen Mahurkar catheter placed while she was awake, and had had axillary venous access through this approach on two previous occasions using a triple-lumen catheter.
The axillary vein lies entirely outside the chest cage and hence can be cannulated without lung injury. This technique avoids the risk of injury to the pleura or the lung because the puncture site is far lateral and the introducer sheath may not even reach the first rib (Fig. 3). Through visualization of the needle with real-time sonography, injuries to the axillary artery or the brachial plexus can be avoided. Most introducer sheaths are designed for the subclavian vein and may barely reach the axillary vein in a hypersthenic patient. There is a need for longer introducer sheaths for this procedure in hypersthenic patients. Longer needles may be required to approach deeper veins at an acute angle. Often, while the guidewire passes through the needle after successful subclavian or axillary vein puncture, more than usual resistance is encountered and the procedure is abandoned for fear of venous perforation. We have observed the advance of the wire into the proximal superior vena cava by repositioning the probe. With ultrasound, we can visualize the guidewire position, coiling of the wire against a valve, or misdirection into tributaries of the axillary or jugular veins, both ipsilateral and contralateral. In these situations, the guidewire can be pulled back and redirected into the required position under observation. The technique of transpectoral ultrasound-guided catheterization of the axillary vein was used in 30 patients in whom difficulty inserting central lines using traditional techniques was encountered or anticipated. None of the 30 patients catheterized by the author had arterial puncture, nerve injury, or pneumothorax. Unintended arterial punctures are avoided, because all steps in this procedure are performed with real-time imaging. A larger prospective study is required to prove the techniques efficacy, describe its complications, and compare it with the standard technique of subclavian cannulation. The technique was successful even when used by residents who performed it for the first time, with the author holding the probe. Axillary lines present the risk of thrombosis, as do most central venous lines. There have been no more reports of excessive thrombosis in any of the previous literature than seen in traditional subclavian central venous lines (6,10,11). More data must be collected over a longer period to assess the risk of thrombosis for the transpectoral technique. In summary, imaging of the axillary vein in longitudinal section allows simultaneous visualizing of the entire needle, the guidewire, the dilator, and the catheter. This most important step prevents injury to surrounding structures. This is an improvement over previously described techniques of ultrasound-guided central venous line placement using a transverse image of the vein, where the needle is not always visualized.
These are routine cases and no special funding was required other than that provided by the Department of Anesthesiology, New York University School of Medicine. I thank Dr. Sanford Miller, MD, and Dr. Shyamala Karuvannur, MD, for their help in editing the manuscript.
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