Background: Intravascular catheter infections are common events among hospitalized patients. They are associated with high morbidity, mortality and resource utilization. The main objective of this Privat-Docent thesis was to explore specific determinants (i.e., patient-, catheter type-, catheter insertion- and catheter care-related) of intravascular catheter infections in order to optimize the prevention of these severe infections. First, we investigated the role of body mass index in intravascular catheter infections in critically ill obese patients. Second, we described the differences in the infection risk between central venous and short-term dialysis catheters. Third, we investigated the impact of ultrasound guidance on intravascular catheter infection risk. Fourth, we analyzed the incidence of intravascular catheter infections in peripheral venous catheters after switching from routine to clinically indicated catheter replacement.

Methods: We created two large cohorts using individual patient (French cohort) and aggregated (Geneva cohort) data. We performed descriptive statistics and analyzed the data using survival analyses and Poisson regression models.

Results: i) Patients with BMI =40 had an increased risk for intravascular catheter infections probably due to dressing disruptions. ii) The risk of infection for short-term dialysis catheters was significantly higher than central venous catheters within the first seven days of catheter maintenance. iii) We showed an increased infection risk for ultrasoundguided insertion (versus anatomical landmarks) in central venous catheters. iv) Routine replacement (versus clinical indicated) of peripheral venous catheters was associated with a decreased risk of intravascular catheter infections.

Conclusions: On one hand, we closed the knowledge gap for certain prevention measures (e.g., routine replacement of peripheral venous catheters) and, on the other hand, we discovered new challenges for future research in this field (e.g., what is the correct utilization of ultrasound for intravascular catheter insertion, or what are optimal prevention measures for critically ill obese patients).