A Tale of Two Wires: In Response

Abstract

We thank Auden et al. (1) and appreciate their interest and comment on our letter regarding central venous cannulation in neonate. Actually, we often encounter difficulty in threading a guidewire into small vessels (<3 or 4 mm diameter) despite good blood return. In such cases, we used to choose a straight end by reversing the opposite side of a J-shaped tip guidewire. Since the straight wire has been implicated in perforation of vessel walls, we also prefer to use a flexible, slightly angled wire. The course of the right internal jugular vein has been shown to be almost straight (2). We agree with their comments of using a flexible, relatively straight wire as a first choice in obtaining internal jugular access for small infants. However, when we access tortuous veins such as external jugular, antecubital, or basilic veins, the J-shaped tip has advantage over the straight tip. The smooth convexity of the J-shaped tip may enable the wire to pass corners easily. As we mentioned in the letter (1), the J-shaped guide wire bends introducer catheter excessively. The angle shaped wire can also bend the catheter slightly. We would like to emphasize that the catheter material affects the distortion. Catheters made of Teflon, polyethylene, or polypropylene are relatively stiff so that they are difficult to bend with J-shaped guide wire insertion. Although new catheters made of polyurethane have superior mechanical properties (tensile strength and wearing resistance), the catheter is softer than the older materials. Hence it is not recommended for insertion of J-shaped guidewire. The introducer catheter should be used only for cannulation. Therefore, relatively stiff catheters may be desirable. Shin Nakayama, MD Shinji Takahashi, MD Hidenori Toyooka, MD