I do use it in infants but not on a regular basis. It does give great pictures as the windows are less and the waves penetrate the less ossified bones.
We published the initial papers in 2005 in locating the catheter and tip with US.
I use S Nerve and portex. I use 18G catheters for bigger than 2 kg babies. We tend to leave catheters for 48H even caudal catheters. Tegaderm dressing and tegaderm sandwich at filter level to prevent disconnections.
If unilateral survey then TAP blocks but midline surgery etc I use neuraxial block