Ultrasound vs. touch: which gets the IV right the first time?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age 12 years or older. * Requires peripheral venous vascular access as part of clinically indicated care. * Considered medically appropriate for peripheral intravenous catheter placement. * Able to undergo either ultrasound-guided or standard peripheral vascular-access procedures according to the study protocol. * For participants age 18 years or older, able to provide informed consent or participate under another IRB-approved consent process. * For participants younger than 18 years, permission from a parent or legally authorized representative and participant assent will be obtained when required by the reviewing IRB and applicable regulations. * Vascular access is expected to be performed at an anatomical site suitable for peripheral venous catheterization. * Participants with or without difficult intravenous access may be enrolled. * Willing and able to complete protocol-required procedural assessments and follow-up when applicable. Exclusion Criteria: * Immediate life-threatening or emergency circumstances in which study enrollment, consent, assent, parental permission, or randomization could delay medically necessary treatment. * Existing functional vascular access that eliminates the clinical need for a new peripheral intravenous catheter. * Clinical requirement for immediate central venous, intraosseous, midline, PICC, or other non-peripheral vascular access rather than peripheral cannulation. * Infection, significant burn injury, major trauma, vascular injury, or another condition at the proposed access site that makes peripheral cannulation inappropriate. * Known vascular abnormality or another clinical condition that, in the judgment of the treating clinician or investigator, makes either randomized vascular-access strategy inappropriate or unsafe. * Inability to undergo either study-assigned vascular-access approach. * For participants younger than 18 years, inability to satisfy applicable parental permission and assent requirements unless an IRB-approved exception applies. * Participation in another interventional study that, in the investigator's judgment, could materially interfere with assessment of vascular-access outcomes. * Any medical, procedural, or logistical circumstance in which participation could interfere with timely delivery of clinically necessary care.