As an Emergency Nurse, I've noticed this, too, with our peripheral lines. (Our central line pts. are usually too sick to care). I didn't believe it before when I rarely heard of it (Why, NS just "blends right in with the body.") It does seem more frequent now (~15%, and more likely with rapid push). Nowadays, however, more lines are locked than infused or TKO'ed. I now caution patients about it. I'll have to try the "hold your breath" tip!
Tom Trimble, RN CEN