Hydrogel and Hydrophilic Catheters

Nancy Moureau, RN, PhD, CRNI, CPUI, VA-BC

Intravenous (IV) catheters are commonly used in hospitals and medical facilities to administer medication, fluids, and nutrients directly into a patient's bloodstream. Blood cell adherence occurs within minutes of the insertion of polyurethane or silicone catheters into the bloodstream. The material biocompatibility and cellular adherence for IV catheters can significantly impact catheter function and patient outcomes. Materials used for IV, peripherally inserted central catheters (PICCs), and Midline catheters are primarily composed of polyurethane and silicone materials. These material surfaces allow varying degrees of protein and cellular adherence that may lead to catheter-related thrombosis, occlusion, and or infection. Material types and properties were investigated comparatively in a recent integrative review in relation to catheter complications (Moureau et al., 2022). Prevention of thrombosis, catheter occlusion, and infection are high priorities for maintaining catheter function for IV infusions (Chopra et al., 2012; Helm et al., 2015; Liem et al., 2012; Swaminathan et al., 2022). Two polyurethane material modifications used in IV catheters are hydrogel and hydrophilic polymer composites or coatings that may reduce or prevent cellular and microorganism adherence (Ullman et al., 2021).

Hydrogel is a water-absorbing hydrophilic polymer that swells when it comes into contact with liquid (Aswathy et al., 2020). In the hydrated state, the catheter surface becomes more slippery or lubricious. It is commonly used in medical devices because of its biocompatibility and ability to mimic the natural environment of human tissue. The hydrogel's water-absorbing properties also help to keep the catheter lubricated and reduce friction during insertion and removal. Hydrogel composite catheters are designed to reduce adherence of blood cells and bacteria, resulting in material properties with reduced risk of catheter-related bloodstream infections (CRBSIs) (Mannarino et al., 2020; Zhang et al., 2021). The slippery catheter surface prevents bacterial attachment and the formation of biofilms on the catheter surface. Biofilms are a polysaccharide produced by microorganisms designed to protect the microorganism and allow unimpeded colony growth on the catheter surface, leading to catheter-related infections. 

Hydrophilic catheter properties are derived from polymers that make the catheter surface more slippery and the catheter easier to insert. This property is created from materials with a high affinity for water, allowing them to absorb moisture and reduce friction. Compared to the average polyurethane PICC and midline material, platelet adhesion is reduced by 97% for a catheter with consistently hydrophilic surfaces (Mannarino, 2020). Recent complication benchmarking results established the significant economic impact for three common complications representing substantial costs for healthcare services (Moureau et al., 2022).

Composite hydrophilic polymers are composed of heat-treated chemical, ionic, and crosslinked substances that provide high-strength long-lasting lubricious surfaces (LeRoy & Donahue, 2023). There are several advantages to using hydrophilic catheters. First, they are highly biocompatible, reducing inflammatory and cellular reactivity commonly associated with IV catheter insertions. Second, the hydrophilic catheter’s slippery surface makes catheterization easier.  The amount of force needed to navigate has been shown to be 84-90% lower than polyurethane catheters (LeRoy & Donahue, 2023). This could help reduce damage to the endothelial lining of the vessel. Finally, catheters with hydrophilic properties have shown evidence of being antimicrobial which reduces the risk of catheter-related infections and anti-thrombotic, reducing blood cell adherence-related complications (Zhang, 2021; Sukavaneshvar, 2017).

In summation, hydrogel and hydrophilic composite materials and coatings are commonly used in IV catheters to improve their performance and biocompatibility. Hydrogel is used to prevent cellular adherence and the formation of biofilms on the catheter surface while reducing friction during insertion and removal. Hydrophilic properties make catheterization easier and more comfortable for the patient, reduce the risk of thrombotic complications, and improve catheter performance. A catheter that is both hydrophilic and a hydrogel may provide the best of both materials. Choosing the right material for an IV catheter can reduce the risk of complications and improve patient outcomes.

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