From: Ultrasound-guided peripheral venous cannulation in critically ill patients: a practical guideline
Key concept | Description | Considerations |
---|---|---|
Must know | Basic general knowledge for ultrasound-guided vascular cannulation | Selection of the transducer and preset; image orientation; basic image optimization; distinguishing veins versus arteries; managing techniques of cannulation (out-of-plane and in-plane technique) |
1 | Select superficial veins (i.e., epifascial) | Superficial veins: short pathway to reach the vein; high probability that a great proportion of the catheter will dwell in the vein Deep veins: inherent risks of needle-stick injury of the artery or the nerve; frequent catheter dislodgment |
2 | Patent veins | Anechoic lumen; fully compressible Do not misinterpret stagnant blood in the vein lumen with thrombus (distal compression is useful) |
3 | Vein size: anteroposterior diameter ≥ 4 mm | AP diameter (mm) = maximum Fr catheter size (e.g., 4 mm = up to 4-Fr catheter) |
4 | Vein depth: up to 16 mm (short axis) | Real distance to reach the vein (45° insertion angle)*: 1.4 × vertical distance *Ideally measure real distance in long axis and select the best angle of insertion ≥ 2.75 cm of the catheter must dwell in the vein Consider using ultra-long peripheral (6.3 cm) and midline (8–20 cm) catheters to minimize catheter failure |
5 | Select the technique: in-plane or out-of-plane technique | Both are useful, although it seems to be a greater success rate with the out-of-plane technique Learning and using both techniques is encouraged |
6 | Checking catheter position | Direct: double hyperechoic line into the lumen vein Indirect: saline flush test (two-dimensional and/or color Doppler) |