Clinical Utility of Ultrasonographic Guidance for Arterial Catheterization in Patients with Obesity: A Randomized Controlled Trial

Objectives: To compare the success and complication rates of radial artery catheterization using ultrasound guidance versus the conventional palpation technique in obese patients by anesthesia residents with similar levels of experience in both methods, and to measure the skin-to-artery distance of radial, brachial, and dorsalis pedis arteries using ultrasound with standardized anatomic landmarks. Design: Prospective, randomized controlled trial Setting: Single tertiary center Participants: Eighty adults with a body mass index (BMI) ≥30 kg/m2 Interventions: Ultrasound guidance or conventional palpation method Measurements and Main Results: The primary outcome was the first-attempt success rate of arterial catheterization. The skin-to-artery distance of the radial artery was significantly greater in the BMI groups of 40 to 49 kg/m2 and ≥50 kg/m2 compared to the BMI group of 30 to 39 kg/m2 (mean difference, 1.0 mm; 95% confidence interval [CI], 0.4-1.7; p = 0.0029) for BMI 40-49 kg/m2 vs 30-39 kg/m2 and 1.5 mm (95% CI, 0.6-2.4 mm; p = 0.0015) for ≥50 kg/m2 vs 30-39 kg/m2. Similar findings were observed for the brachial artery. BMI was inversely associated with first-attempt success rates (p = 0.0145) and positively with time to successful catheterization (p = 0.0271). The first-attempt success and vascular complication rates of catheterization did not differ significantly between the ultrasound guidance group (65.0% and 52.5%, respectively) and the conventional palpation group (70.0% [p = 0.6331] and 57.5% [p = 0.6531], respectively). Conclusion: The results of this study do not support the routine use of ultrasonography during radial arterial catheterizations for obese adults when junior practitioners perform the procedure.