Short-Axis Versus Long-Axis Ultrasound-Guided Peripheral IV Cannulation in Adults

This single-centre, parallel-group randomized controlled trial was conducted in the Department of Anaesthesiology at Medical Teaching Institution-Lady Reading Hospital, Peshawar, Pakistan.

A total of 222 eligible adults requiring peripheral intravenous access were enrolled through consecutive sampling. Participants were randomized in a 1:1 ratio using a computer-generated sequence. In the short-axis group, the ultrasound probe was positioned perpendicular to the target vein to obtain a transverse image, and the needle was advanced using an out-of-plane technique. In the long-axis group, the probe was positioned parallel to the vein to obtain a longitudinal image, and the needle was advanced in plane while maintaining visualization of the needle tip. Experienced anaesthesiologists performed all procedures.

Cannulation was considered successful when the catheter advanced without resistance, blood returned freely into the hub, and saline could be flushed without local swelling. The primary outcome was successful peripheral intravenous cannulation. Secondary outcomes included cannulation time, number of attempts, and immediate complications comprising arterial puncture, extravasation, and haematoma. No delayed follow-up outcomes were assessed.

Inclusion criteria

• Men and women aged 20 to 60 years
• Required peripheral intravenous access

Exclusion criteria

• Body mass index of 30 kg/m² or greater
• Infection at the intended cannulation site
• Upper-limb deformity
• Previous venous thrombosis
• Refusal to participate