Fourth step for ultrasound-guided central vein catheterization.

Editor—We read with great interest the article by Tokumine and colleagues. The authors have introduced and demonstrated the safest method for central venous catheterization under real-time ultrasound guidance using the long-axis view of the vessel with the in-plane needle approach. As they have pointed out, the ultrasound-guided procedure with the short-axis view of the vessel with the out-of-plane needle approach would increase the success rate of venous puncture, although the technique will never be able to prevent unintentional penetration of other vital structures, including the carotid artery and pleura. Strictly executing the three-step method, our anaesthesiologists could accomplish safe and practical catheterization. Longitudinal ultrasound imaging is the most essential and important factor. Interestingly, the pictures demonstrated by the authors were very similar to our presentations. The National Institute for Clinical Excellence (NICE) guidelines of 2002 (reviewed in 2005) 5 recommend ultrasound guidance for central venous cannulations; however, the detailed practical description including the axis of ultrasound is not found in the text. When physicians endeavour to establish the safest methods for central venous catheterization, many practitioners would reach a similar conclusion, 7 that is, the long-axis, in-line real-time ultrasound guidance technique. The three-step method could be considered to be an almost perfect way and there might be no room for discussion. However, we would like to append a fourth step. In our intensive care unit, the supervisor requires the operator to confirm appropriate i.v. guidewire placement by ultrasound examination before the insertion of a large-bore dilator and catheter. The intensivists track the guidewire as far as is possible to the limits of ultrasoundvisibility. Theultrasound probe is placed onasupraclavicular fossa, and when the internal jugular vein is accessed, we usually confirm the correct placement at the level of branching of the jugular vein and subclavian vein. The detection of the guidewire in the jugular vein near the entry site is never a guarantee for an appropriate placement. 2 The penetration of the posterior wall of the internal jugular vein and other vital structures can occur at a site more proximal than the skin puncture. Thus, extensive tracking of the guidewire before the largebore cannulation is recommended as the fourth step of the method introduced by Tokumine and colleagues. We have no results of clinical investigation on this improvement so further study is required.