Posterior Wall Punctures Between Long- and Short-Axis Techniques in a Phantom Intravenous Model.

OBJECTIVES: To determine whether a long-axis, in-plane approach to ultrasound-guided vascular access produces fewer posterior wall punctures than a short-axis, out-of-plane approach when attempted by novices without prior ultrasound-guided procedural experience.

METHODS: Participants were randomized to perform either technique on a ballistic gel-based phantom in a randomized controlled trial. They were then crossed over to repeat the experiment using the alternative approach. The primary outcome was posterior wall puncture occurrences. Secondary outcomes included cannulation success, the time to cannulation, and provider preferences. These were formulated before data collection.

RESULTS: Forty participants completed the study. There were 6 posterior wall punctures in the short-axis, out-of-plane approach (15%) and 1 in the long-axis, in-plane approach (2.5%). A posterior wall puncture was less likely to occur when the long-axis approach was used (odds ratio, 0.15; 95% confidence interval, 0.02-0.91). There was no statistical difference in rates of successful cannulation and the time to cannulation. Eighty percent preferred the long-axis approach, whereas 85% stated that the long-axis approach provided better visualization of the needle tip throughout the procedure.

CONCLUSIONS: The long-axis, in-plane approach compared to the short-axis, out-of-plane approach for ultrasound-guided cannulation on a phantom resulted in fewer posterior wall punctures, better needle tip visibility, and higher preference among novices.