Chapter 8. Intravenous Therapy
8.8 Flushing and Locking PVAD-Short, Midlines, CVADs (PICCs, Percutaneous Non Hemodialysis Lines)
In Chapter 7.6 we discussed flushing before and after administration of an IV direct medication. Recall that the rationale for the initial flush was to ensure IV patency so that the medication would be administered via the correct route. The flush following the medication administration was to clear the extension tubing and to maintain patency of the venous access device until the next time it required access.
In this section we discuss flushing and locking of PVAD-short catheters and CVADs (PICCs and percutaneus non hemodialysis catheters) as part of routine care and maintenance. Flushing and locking of IVADs, CVAD hemodialysis lines, and tunnelled catheters require additional education and training beyond the scope of this textbook.
If IVs are not being infused, they are often locked. Locked lumens require care and maintenance to allow them to remain patent until the next time they are needed. PVAD-short cannulas that are locked are commonly referred to as a saline lock (Figure 8.21) . CVADs that are locked are referred to as being either capped or locked; for example “a locked PICC,” “a capped percutaneous non hemodialysis CVAD,” or “a PICC with one capped lumen and two accessed lumens.” (See Figure 8.6.)
Routine flushing and locking of IV catheters is meant to prevent catheter occlusion (Goossens, 2015). Besides mechanical reasons, IV catheter occlusion can result from blood clot (fibrin) in the lumen or at the catheter tip and/or build up of precipitates in the lumen from medications and parenteral nutrition. Flushing and locking protocols are meant to maintain patent lumens. In addition, proper flushing and locking might eliminate potential nesting material for microorganisms and as such reduce the risk of catheter related blood stream infections (Ferroni et al., 2014).
Historically a positive pressure technique was used to prevent back flow of blood into the IV catheter; thus posing a risk of occlusion. Manual ways of achieving positive pressure include disconnecting the syringe from the needleless cap while still exerting pressure on the plunger during the last 0.5 ml. Another technique involves clamping the catheter while injecting the last 0.5 ml. Fast forward to the present and we now have technology to help us. Neutral displacement and positive pressure valves (caps) can be used and some IV catheters have valves built into their structure to prevent back flow of blood into the lumen. In addition, some syringes are specifically designed and if used correctly (remove the syringe before bottoming out) create the necessary positive pressure to prevent blood reflux into the catheter (Goossens, 2015).
Understanding the available IV equipment will direct the nurse to the proper flushing and locking protocols. This includes knowing what kind of venous access device the patient has, what solutions are being infused a