The Qualifier None is identified by letter "Z" and occupies the 6th position in the ICD10-PCS procedure code structure.
Below a selection of ICD 10 PCS codes related to B546ZZ
Ultrasonography of Right Subclavian Vein
Ultrasonography of Right Subclavian Vein, Intravascular
Ultrasonography of Right Subclavian Vein, Guidance