Complications associated to midline- and long peripheral catheters in adults. Systematic review of literature and proposal for a standardized model for data collection.

INTRODUCTION: Long peripheral catheters (LPCs) and midline catheters (MCs) are indiscriminately labelled with different names, leading to misclassifications both in primary and secondary studies. The available studies used different methods to report the incidence of catheter-related complications, affecting the possibility of properly comparing the catheter outcomes. The aim of this review was to explore the complications related to LPCs and MCs after reclassifying according to their length.

METHODS: Systematic literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, conducted on PubMed, Scopus and CINAHL databases. The study protocol was registered in the International Prospective Register of Systematic Reviews. Data regarding LPCs and MCs were compared. Catheter outcomes were classified into major and minor complications, recomputed and reported as cases/1000 catheter-days.

RESULTS: Fourteen studies were included. Over-half of the devices were correctly labelled by the authors, misclassifications affected particularly LPCs improperly labelled MCs. The cumulative incidence of catheter-related bloodstream infections was 0.3 and 0.4/1000 catheter-days, that of symptomatic catheter-related thrombosis was 0.9 and 1.8/1000 catheter-days for MCs and LPCs, respectively. Minor complications and catheter failure were higher for LPCs.

CONCLUSIONS: A misclassification exists in the labelling of MCs and LPCs. A widespread heterogeneity of diagnostic criteria adopted to classify the catheters' outcomes was found, exposing the risk of misestimating the incidence of complications and undermining the possibility of effectively comparing results of the published research. We proposed a list of definitions and relevant variables as a first step toward the development of standardized criteria to be adopted for research purposes.