EXPRESS: Effect of Vein Characteristics and Operator Experience on Intravenous Catheter Insertion Success in Cats in an Emergency Room

Objectives: To identify patient, vein, and operator factors associated with first-attempt success of peripheral intravenous catheter (PIVC) insertion in cats presenting to an emergency room. Methods: A prospective study was conducted in the Emergency Room of a university small animal hospital from February to April 2024. Cats requiring PIVC insertion were enrolled. Data collected included patient signalment, vein visibility and palpability, catheter size, indication for catheterization, and operator characteristics (role, years of experience, and estimated number of previous PIVC insertions). First-attempt success was defined as catheterization with visible blood flashback and successful flushing without extravasation or discomfort. Univariable and multivariable logistic regression analyses were performed to assess associations with first-attempt success. Results: Ninety-seven PIVC insertions in 95 cats were analyzed. Overall, first-attempt success was 85.6% (83/97). Most insertions involved the cephalic vein (96.9%) and 22G catheters (57.7%). Neither catheter size, target vein, nor indication for insertion was significantly associated with success. Operators with 8–15 years of experience had significantly higher odds of success compared with those with ≤2 years (P = 0.03). Operators who had inserted >500 IVCs had greater odds of success than those with <100 insertions (OR 8.63; 95% CI 1.48–50.12; P = 0.02). Vein visibility was strongly associated with first-attempt success (OR 7.78; 95% CI 2.29–26.42; P = 0.001), while palpability was not. In the final multivariable model, both vein visibility (OR 8.0; 95% CI 2.16–30) and >500 prior insertions (OR 13.24; 95% CI 1.54–144) remained independently associated with success. Conclusions and relevance: First-attempt IVC success in cats is strongly influenced by operator experience and vein visibility. These findings highlight the clinical importance of operator training and vein assessment during catheter insertion in feline emergency patients.