Anti-fouling strategies for central venous catheters

Abstract

Central venous catheters (CVCs) are ubiquitous in the healthcare industry and carry two common complications, catheter related infections and occlusion, particularly by thrombus. Catheter-related bloodstream infections (CRBSI) are an important cause of nosocomial infections that increase patient morbidity, mortality, and hospital cost. Innovative design strategies for intravenous catheters can help reduce these preventable infections. Antimicrobial coatings can play a major role in preventing disease. These coatings can be divided into two major categories: drug eluting and non-drug eluting. Much of these catheter designs are targeted at preventing the formation of microbial biofilms that make treatment of CRBSI nearly impossible without removal of the intravenous device. Exciting developments in catheter impregnation with antibiotics as well as nanoscale surface design promise innovative changes in the way that physicians manage intravenous catheters. Occlusion of a catheter renders the catheter unusable and is often treated by tissue plasminogen activator administration or replacement of the line. Prevention of this complication requires a thorough understanding of the mechanisms of platelet aggregation, signaling and cross-linking. This article will look at the advances in biomaterial design specifically drug eluting, non-drug eluting, lubricious coatings and micropatterning as well as some of the characteristics of each as they relate to CVCs.

Keywords: Biofouling; catheters; central venous catheters (CVCs); infections; thrombosis.

Figure 1

Infectious fouling of catheters can occur by migration of bacteria from the surface of the catheter, from the lumen of the catheter and from hematogenous seeding. Biofilms protect the bacteria from mechanical motion and antibiotics. Prevention guidelines have been well established (13,14).

Figure 2

Demonstration of the one-way valve effect of incomplete occlusion by a fibrin sheath.

Figure 3

The major development steps of thrombosis on a surface. Protein adsorption to the surface causes a localized increase in concentration that promotes cellular adhesion. Cellular adhesion activates cascading effects to promote aggregation (35). Stabilization then occurs via fibrin cross-linking. Neutrophil extracellular traps may increase thrombotic events (36). Artificial surfaces can exacerbate portions of these steps (37,38).

Figure 4

Macroscopic image of a central venous catheter with an associated micro-CT image of a central venous catheter in a longitudinal, split and opened view. Note the smooth surface with eyelets near the end.

Figure 5

Slippery liquid-infused porous surfaces are a unique method of creating self-healing and protective surfaces by creating a porous surface and introducing a liquid with specific properties into the porous material (77-81). The material holds the liquid within the pores and as a thin layer on the surface to create highly protective surfaces.