Local infection signs at the catheter-insertion site: a large prospective multicentric cohort study

To describe the epidemiology of local signs at intravascular catheter-insertion sites across catheter types and care settings, to compare the identification of redness between local investigators and experts, and to evaluate the association between redness and blood culture positivity in patients with suspected infection.

DeepCath was a prospective multicentre cohort study conducted between September 2022 and December 2023 in France and Switzerland. Adult patients with short-term central venous catheters, arterial catheters, peripheral venous catheters, peripherally inserted central catheters (PICCs), or midlines were included. Local investigators captured one photograph per insertion site and recorded local signs. Four experts independently reassessed all images, serving as the reference standard. Agreement between local investigators and experts on redness was evaluated using Cohen's kappa. Among patients with suspected infection, the association between redness and blood culture results was evaluated.

Among 5164 collected images, 2670 eligible catheters (one image per catheter) were analysed: 1447 peripheral venous catheters (54.2%), 608 central venous catheters (22.8%), 296 arterial catheters (11.1%), and 319 PICCs/midlines (11.9%). Local investigators reported signs of local infection in 257 of 2670 catheters (9.6%), mainly redness (218 of 2670, 8.2%). Experts identified local infection signs in 376 of 2670 catheters (14.1%), including redness in 364 of 2670 (13.6%). Redness prevalence varied by catheter type and was highest for PICCs/midlines (82 of 319, 25.7% by expert assessment). Overall agreement for redness was fair (Cohen's kappa of 0.40, 95% CI 0.35-0.46) and was observed in 2358 of 2670 images (88.3%). Among 732 patients with suspected infection who underwent blood cultures diagnostic, redness was more frequent in those with positive cultures (23 of 71, 32.4%) than in those with negative (15 of 225, 6.7%) or pending cultures (40 of 436, 9.2%; p < 0.0001).

Local signs at catheter-insertion sites are frequent and differ across catheter type. Redness is underrecognised in routine clinical assessment compared with expert review, supporting the need for standardized, potentially artificial intelligence-assisted approaches in daily practice.