Factors associated with first-attempt success of peripheral arterial catheterization in a pediatric intensive care unit: a prospective observational study.

Background: Peripheral arterial catheterization (PAC) is widely used in pediatric intensive care units (PICUs) for continuous hemodynamic monitoring and arterial blood sampling. However, achieving successful arterial access in critically ill children remains technically challenging, and evidence regarding factors associated with first-attempt success is limited. Methods: A prospective observational cohort study was conducted in a tertiary PICU. Critically ill children who underwent PAC between April 2024 and May 2025 were included. Each catheterization procedure was treated as the unit of analysis, with clustering at the patient level. Patient-, disease-, procedure-, and peri-procedural variables were collected. The primary outcome was first-attempt success, defined as successful arterial catheterization within a single skin puncture at the intended site with limited needle redirection, resulting in a functional arterial line suitable for continuous blood pressure monitoring or arterial blood gas sampling. Factors associated with first-attempt success were evaluated using multivariable generalized estimating equation (GEE) logistic regression models. Results: A total of 320 PAC procedures were analyzed, with an overall first-attempt success rate of 65% (208/320). In multivariable GEE logistic regression analysis, insertion site and catheterization technique were independently associated with first-attempt success. Compared with radial artery catheterization, cannulation at the dorsalis pedis artery (OR 0.41, 95% CI 0.20-0.83), and ulnar artery (OR 0.35, 95% CI 0.13-0.98) was associated with lower odds of success. Ultrasound-guided catheterization was associated with higher odds of first-attempt success compared with the blind technique (OR 2.10, 95% CI 1.08-4.08). Using early ultrasound rescue at the second attempt as the reference, ultrasound introduced after the fourth attempt was associated with a higher number of cannulation attempts (IRR 3.81, 95% CI 2.05-7.08). Conclusion: First-attempt success of PAC in critically ill children is influenced by both puncture site and catheterization technique. Preferential use of the radial artery and ultrasound guidance may improve cannulation success in the PICU. Early adoption of ultrasound guidance after failed landmark-guided attempts may help reduce repeated cannulation attempts.