Perineural ultrasound-guided catheter bacterial colonization: a prospective evaluation in 747 cases

Ultrasound guidance is increasingly used for catheter insertion and could make it more complicated to guarantee aseptic insertion of catheters. The current study evaluated the incidence of colonization of ultrasound-guided perineural catheter (US-PNC) placed for postoperative analgesia.

We evaluated prospectively for 14 months 760 ultrasound-guided catheters in a single center placed under sterile conditions. Quantitative culture of all the catheters was performed after withdrawal. Colonization was defined as ≥10(3) colony-forming units/mL. Infection was defined as the isolation of the same microorganism from the colonized catheter and from blood culture and/or culture of an abscess. Univariate and multivariate logistic regression analyses were performed to determine the independent risk factors of US-PNC colonization.

Incidences of colonization and infections were 10.4% (95% confidence interval [95% CI], 8.2%-14.4%) and 0.13% (95% CI, 0%-3.8%), respectively, in a total of 747 catheters. Coagulase-negative staphylococci colonization was documented in 69% of the colonized catheters. Local inflammation was more frequently noted when catheters were colonized (26.9% [95% CI, 15.2%-38.7%] versus 8.1% [95% CI, 4.2%-11.9%], P = 0.005). Independent factors for ultrasound-guided catheter colonization were duration of catheter placement more than 48 hours (odds ratio [OR], 4.9; 95% CI, 1.1-12.7; P = 0.003), diabetes (OR, 2.3; 95% CI, 1.4-9.6; P = 0.004), and antibiotic administration during the month preceding surgery (OR, 1.8; 95% CI, 1.5-7.8; P = 0.01).

Although infection rate is low, there is a risk of ultrasound-guided catheter colonization that deserves careful monitoring of the insertion site in the postoperative period.