Ultrasound-guided peripheral intravenous catheters insertion in patient with difficult vascular access: Short axis/out-of-plane versus long axis/in-plane, a randomized controlled trial

Purpose: The aim of this study was to evaluate the rate of successful peripheral cannulation between short-axis and long-axis ultrasound guided techniques. Methods: A single-center, two-arm randomized controlled, intention-to-treat, open-label study was conducted at the Emergency Department, between August and November 2020. Patients requiring a peripheral intravenous catheter insertion and identified as having a difficult intravascular access, were enrolled and followed for up to 96 h. The primary endpoint was the correct placement of the peripheral intravenous catheter. The secondary endpoints were number of venipunctures, intra-procedural pain, local complications, and positive blood return during the follow up. Results: A total of 283 patients were enrolled: 141 subjects were randomized to the short-axis and 142 to the long-axis group. Success rate was 96.45% (135/141; 95% CI, 91.92%-98.84%) in the short-axis group compared with 92.25% (132/142; 95% CI, 86.56%-96.07%) in the long-axis group (p = 0.126). No significant differences were found in terms of intraprocedural pain and local complications. Higher rate of positive blood return at 72 h [3/17 long-axis, 14/17 short-axis (p = 0.005)] and 96 h [1/10 long-axis, 9/10 short-axis 96 h, (p = 0.022)] was found for the short-axis group. Conclusions: No differences were found between short-axis and long-axis techniques in terms of success rate, intraprocedural pain, and local complications. Despite this, a slightly higher success rate, a lower number of venipunctures, and a higher rate of positive blood return at 72 and 96 h together with an easier ultrasound technique could suggest a short-axis approach.