Maintenance of catheter lumen patency is an ongoing challenge. Catheter flushing is the primary nursing intervention used to prevent lumen occlusion from thrombotic and precipitate causes. The catheter and all devices attached to it must be regarded as a system in which each component directly affects the others. The technology of catheter flushing includes the flush solution itself, the source of these solutions, syringe design, mechanical pumps, needleless injection systems, and the design of the catheter. Effective catheter flushing is a combination of a technique and technology that requires an understanding of how both must work together.