Surface modification of intravenous catheters to reduce local tissue reactions

Surface modification of polymer materials used in intravascular catheters reduces the in vitro adhesion of plasma proteins involved in blood coagulation. Intravenous Teflon cannulae, native and surface-modified with ethyl hydroxyethyl cellulose, were compared using clinical examination and laser Doppler flowmeter (LDF) measurements of local cutaneous blood flow. Nine volunteers were simultaneously subjected to both types of cannulae for a period with a maximum of 4 d. Native Teflon catheters showed a larger incidence of catheter-associated tissue reactions, first demonstrated by early increases in laser Doppler recordings of skin blood flow. These results indicate that surface modification of polymer intravascular catheters attenuates tissue response against the foreign material and that altered LDF measurement precedes the clinical recognition of thrombophlebitis.