Evaluation of the Efficacy and Safety of Midline Venous Catheters

Central venous catheters are fundamental tools in medical practice, but their use carries frequent local and systemic complications, with bloodstream infection (bacteremia) and thrombus formation being the most frequent and serious. Both complications prolong hospitalization time, increase morbidity, mortality, and hospital costs. Promoting policies to prevent catheter-associated infections (CAIs) not only reduces the number of complications but is also essential to mitigate and control the development of multidrug-resistant organisms. The mechanism by which catheters become colonized is multifactorial and complex. Mainly, bacteria access the catheter through three access routes: 1) migration of superficial organisms that follow the path of the catheter until they colonize its tip. Generally, this extraluminal form of colonization causes bacteremia in the first days of catheterization. 2) The intraluminal route is the most frequent form of colonization. Inadequate cleaning of system connections, especially in multiple-lumen and multiple-path catheters, allows bacteria to enter after the first week of use. The third colonization route is rare and is due to hematogenous seeding of bacteria from a distant focus of infection or intrinsic contamination of the infused fluid. Other factors that also favor catheter colonization are the type of material (Teflon is less friendly to the vein), the number of lumens (directly proportional to the risk of infection), the nutritional and immunological deterioration of the individual, the type of infusion administered and the insertion site.

Medium access peripheral venous catheters (MC) are a low-cost, easy-to-place, and highly-durable option that offers greater patient comfort and less pain, among other advantages. They are placed using the Seldinger surgical technique at the foot of the bed, in a simple manner, and under ultrasound guidance. The catheter enters through a peripheral vein near the elbow crease and its tip is positioned at the level of the axillary vein, facilitating the infusion of drugs with an osmolarity <600 mOsm, pH range of 5 to 9, and blood derivatives. The success rate of the procedure is almost 100%, particularly if an expert performs the catheterization.

Midline catheters are an intermediate type of catheter between peripheral and central lines. This makes them a suitable choice for patients who are chronically hospitalized in intensive care units.

The benefits of midline catheters include a longer duration of use compared to peripheral catheters (up to 28 days), a lower incidence of procedure-related complications such as pneumothorax and infections and thrombosis compared to central lines. Moreover, they enable early removal of central lines and can be a viable option for patients with challenging vascular access, aiding in the preservation of venous reserve, which is often disregarded. These factors suggest that their use can result in decreased hospital costs. Unlike centrally inserted catheters, which require a physician's intervention for placement and removal, midline catheters can be inserted and removed by nursing professionals.