Background Hand–eye coordination and ergonomics are important for the success of delicate ultrasound-guided medical procedures. These can be improved using smart glasses (head-mounted display) by decreasing the head movement on the ultrasound screen. The hypothesis was that the smart glasses could improve the success rate of ultrasound-guided pediatric radial arterial catheterization. Methods This prospective, single-blinded, randomized controlled, single-center study enrolled pediatric patients (n = 116, age less than 2 yr) requiring radial artery cannulation during general anesthesia. The participants were randomized into the ultrasound screen group (control) or the smart glasses group. After inducing general anesthesia, ultrasound-guided radial artery catheterization was performed. The primary outcome was the first-attempt success rate. The secondary outcomes included the first-attempt procedure time, the overall complication rate, and operators’ ergonomic satisfaction (5-point scale). Results In total, 116 children were included in the analysis. The smart glasses group had a higher first-attempt success rate than the control group (87.9% [51/58] vs. 72.4% [42/58]; P = 0.036; odds ratio, 2.78; 95% CI, 1.04 to 7.4; absolute risk reduction, –15.5%; 95% CI, −29.8 to −12.8%). The smart glasses group had a shorter first-attempt procedure time (median, 33 s; interquartile range, 23 to 47 s; range, 10 to 141 s) than the control group (median, 43 s; interquartile range, 31 to 67 s; range, 17 to 248 s; P = 0.007). The overall complication rate was lower in the smart glasses group than in the control group (5.2% [3/58] vs. 29.3% [17/58]; P = 0.001; odds ratio, 0.132; 95% CI, 0.036 to 0.48; absolute risk reduction, 24.1%; 95% CI, 11.1 to 37.2%). The proportion of positive ergonomic satisfaction (4 = good or 5 = best) was higher in the smart glasses group than in the control group (65.5% [38/58] vs. 20.7% [12/58]; P <0.001; odds ratio, 7.3; 95% CI, 3.16 to 16.8; absolute risk reduction, –44.8%; 95% CI, –60.9% to –28.8%). Conclusions Smart glasses-assisted ultrasound-guided radial artery catheterization improved the first-attempt success rate and ergonomic satisfaction while reducing the first-attempt procedure time and overall complication rates in small pediatric patients. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Point-of-care ultrasound has been integrated into airway management because it allows for rapid and noninvasive assessments. We present 2 cases of unexpected subglottic stenosis in infants during induction of anesthesia. Intubation failed even with endotracheal tubes that were small for patients’ age. Airway ultrasound was used to measure the subglottic airway diameters, which were 2.0 and 3.0 mm in first and second cases, respectively. The severity of subglottic stenosis in the first case was grade III, requiring emergent tracheostomy. In conclusion, airway ultrasound helps to assess possibility of intubation and plan further airway management in children with unexpected difficult airway.