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.
