Evaluate Initial Success Rate of Ultrasound Guided Versus Landmark Approach For Peripheral Intravenous Access

The primary objective of this randomized controlled trial (RCT) is to compare the success rate of obtaining peripheral vascular access with ultrasound guidance versus the traditional, landmark approach among patients with varying degrees of intravenous access difficulty. In addition to comparing overall initial success rates of the two methods, we will also compare the success rates by degree of intravenous access difficulty (3 main subject subgroups) and by operator experience (approximately 20 emergency department technicians). The main hypothesis is that the initial success rate will be significantly higher (5% or greater) for ultrasound guided peripheral intravenous access compared to landmark approach among patients who are judged to have difficult intravenous access but no significant difference (i.e. \< 5%) among patients judged to have easy intravenous access.