Approach and Techniques

Offline Markings

Offline techniques involve external skin markings from ultrasound scans without imaging during needle placement. Changes in patient position, mobility of the skin, and dynamic changes with needle placement and injection limit the utility of this approach, but this approach can be used for neuraxial blocks. The skin adjacent to the sides of the transducer can be marked. Alternatively, a paper clip or solid metal stylet (preferably with dull ends) can be used to create artifact within the field to mark the position of the object. For this technique, spatial compound imaging can be turned off to enhance the artifact. The M-mode center line can be used to facilitate offline markings in the center of the field.