Our ED instructs us if we want to learn it. Our main PA (who works our 'fast track) holds classes from time to time when there is interest, and other RN's who have done plenty of US IVs, when they have time, are more than willing to teach. Neither method is 'official' or provides any sort of certification. But it's just like EJs. Those with the confidence just go ahead and learn it/do it in our ED. It's hard to decide whether or not to learn US IV placement.
1) When only some of the ED RNs know how to do them, they get called to do them often, which takes time away from their own patients.
2) To do one yourself on your own patients takes time away from your other patients, which does not make patients happy.
3) However, to be able to finally get that hard one completed while not having to wait for someone else to finally show up is very useful, not to mention satisfying.