The efficacy of ultrasonography on learning curve and inter-subject performance variability in radial artery cannulation in standardized training for residents: a randomized controlled trial.

Aim: To evaluate the effect of ultrasound (US) on learning curve and inter-subject performance variability of residents in radial artery cannulation.

Material and methods: Twenty non-anesthesiology residents who received standardized training in an anesthesiology department were selected and divided into two groups: anatomy group or US group. After training of relevant anatomy, US recognition and puncture skill, residents selected 10 patients either under US or anatomical localization performing radial artery catheterization. The number and time of successful cases of catheterization were recorded, success rate of first attempt and catheterization, as well as the total success rate of catheterization were calculated. The learning curve and inter-subject performance variability of residents were also calculated. Complications and the residents' satisfaction for teaching and self-confidence before puncture were also recorded.

Results: Compared to the anatomy group, total success rate and the success rate at first attempt were higher in US-guided group (88% vs. 57%, 94% vs. 81%). The average performance time in the US group was significantly less (2.9±0.8 min vs. 4.2±2.1 min) and the mean number of attempts was 1.6, while 2.6 for the anatomy group. With performing cases increasing, the average puncture time of residents in the US group decreased by 19s, while 14s in the anatomy group. More local hematoma occurred in the anatomy group. The satisfaction and confidence degree of residents were higher in US group ([98.5±6.5] vs [68.5±7.3], [90.2±8.6] vs [56.3±5.5]).

Conclusion: US can significantly shorten the learning curve, reduce the inter-subject performance variability, improve the first attempt and total success rate of radial artery catheterization for non-anesthesiology residents.