During robot-assisted urologic surgery, both arms are often placed alongside the body and covered by surgical drapes. This position can make the arterial catheter difficult to access during surgery. A conventional radial arterial catheter placed at the wrist may become compressed or bent because of wrist position or arm fixation, which can cause an inaccurate or dampened arterial blood pressure waveform. A distal radial arterial catheter may be less affected by wrist movement or pressure on the forearm.

This single-center randomized study will include 70 adults undergoing robot-assisted urologic surgery under general anesthesia who require invasive arterial blood pressure monitoring. Participants will be randomly assigned in a 1:1 ratio to ultrasound-guided conventional radial arterial catheterization at the wrist or distal radial arterial catheterization near the anatomical snuffbox or back of the hand.

The main purpose of the study is to determine whether distal radial arterial catheterization reduces clinically significant arterial catheter dysfunction requiring troubleshooting or rescue treatment while the arms are tucked. The study will also compare catheter insertion success, first-attempt success, insertion time, episodes of dampened or lost arterial pressure waveforms, difficulty obtaining arterial blood samples, need for catheter replacement or another arterial access site, and catheter-related complications.