Visualizing the Tip
During the block, keeping the tip in view is of critical importance. Doing so will result in the highest quality block and avoid the most devastating complications. A few factors play into how well the tip displays: the approach, the needle orientation and the needle gauge. As previously stated, the tip is generally easier to visualize with the In-plane approach. Choosing a shallow angle will also help, as it presents more of the needle to the ultrasound beam for reflection. The needle tip should always be oriented such that the bevel is either facing completely towards or completely away from the probe. This way the broadest, most echogenic portion of the tip is available for reflection. Along a similar line, the larger the needle, the easier it is to visualize.
Never advance the needle if you are unsure of the tip position. If you lose the tip, slowly rock the probe on its face to scan through the needle. You may need to rotate the probe to align it with the axis of the needle. If you are still unsure, withdraw the needle slightly and watch for tissue movement. If the tip is not clear, inject 1cc of local anesthetic. This will deform the tissue surrounding the tip, and the anechoic fluid bolus should highlight the tip. If these attempts fail to localize the tip, withdraw the needle and choose a different angle or puncture site.