Ultrasound guided supraclavicular subclavian cannulation: A novel technique using "hockey stick" probe.

Dear Editor,

Cannulation of subclavian vein (SV) is preferred due to reduced infection rates, reduced mechanical problems, reduced risk of thrombosis, and patient comfort. Its large diameter, absence of valves, and ability to remain patent in hypovolemic patients is an added advantage. We describe the use of a L-shaped “hockey stick” probe (HSP) for real time ultrasound (US) guided supraclavicular (SUC) subclavian central line placement.

Patient is placed supine with the head in the neutral position. The US unit is set on its highest resolution with a depth of 2.4 cm. The HSP is placed in sagittal plane, 2 cm above the SUC fossa and lateral to the medial head of sternocleidomastoid muscle with the foot directed posteriorly and stick directed anteriorly. Short axis view of internal jugular vein (IJV) is obtained and the HSP is moved caudally towards the SUC fossa. The HSP is gently rotated so that it is aligned parallel to the clavicle in the SUC fossa with its foot placed posteriorly and the stick directed anteriorly towards the sternal notch [Figure 1]. Semi-axial view of IJV merging with the SV and forming the innominate veinis obtained [Figure 2]. Long axis view of the SV enables real time US guided in plane cannulation and guidewire insertion into the vein.

Figure 1

Hockey stick probe in supraclavicular fossa parallel to the clavicle with foot placed posteriorly and the stick directed anteriorly towards the sternal notch

Figure 2

Ultrasound scan showing IJV merging with SV. The SV can be traced in the long axis

US guided subclavian line placements are challenging; the vein is located under the clavicle and is thus difficult to visualize with a linear probe. Use of a relatively small probe footprint enables optimum fit into the SUC fossa and overcomes this limitation. We read with interest the method described by Takechi et al.,[1] for in-plane US guided cannulation of IJV at the SUC region. The authors used a linear probe and puncture was performed on the lateral wall of the IJV near the junction of the SV. Endocavitary probes have been advocated for US guided catheterisations of the SV in the SUC fossa.[2] But there is no data on the clinical use of this technique as the authors in this study only assessed the participants’ ability to visualize the SC vein; ability to perform cannulation on actual patients was not asessed. We have successfully used the HSP (6-13 MHz)for SUC subclavian cannulations in more than 20 patients. It is easily available, convenient to use and provides a clearer image than an endocavitary probe. The footprint of a curved and straight linear array transducer is 60 mm and 38 mm respectively whereas the corresponding dimensions for a HSP is 25 mm. Thus, it is advantageous for sonographic studies in areas with small acoustic windows.

Pirotte et al.,[3] have used HSP for cannulation of SV via the classical infraclavicularroute in infants and children. They have placed the HSP at the SUC level with its foot on the clavicle and the stick directed medially and slightly cranially. Previous study by Byon et al.,[4] report shorter puncture times and decreased incidence of guidewire misplacement with SUC approach when compared with infraclavicular approach for US guided subclavian cannulations in pediatric patients. Superficial location of the vein; a larger target area and straighter path to the superior vena cava are some of the advantages with the SUC approach.[5] Thus, we advocate US guided SUC subclavian cannulation using the HSP.