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  1. Fernandez, Ritin S. RN, MN (Critical Care)
  2. Griffiths, Rhonda D. MSc (Hons), PhD
  3. Murie, Penny RN


Loss of peripheral intravenous (PIV) catheter patency is a common problem in the clinical setting. A survey of all private and public hospitals in a metropolitan city in Australia was conducted to identify practices related to maintaining patency of PIV catheters. Eighty-three hospitals were surveyed and responses were obtained from all of them. Normal saline was the most commonly used solution for flushing. The frequency for flushing ranged from 4 to 12 hours, and the volume of the irrigant used ranged from 2 to 10 mL in those hospitals where flushing is routine practice. Policy documents were available from only a few hospitals to validate the practice reported. Significant diversity in practices was documented among healthcare organizations.


Insertion of peripheral intravenous (PIV) catheters is a common procedure in hospitals for patients who require medications, fluids, and blood products. 1,2 However, a frequently encountered problem is the loss of patency because of clot or precipitate formation within the catheter and catheter-related phlebitis associated with repeated access. 3-5


Multiple techniques have been used to maintain patency of the PIV catheter and decrease phlebitis, thus minimizing patient discomfort and costs associated with replacement and catheter-related complications. Continuous infusions or intermittent flushing are common practices to maintain patency of the PIV catheter to allow immediate access to the vascular system. 6,7 Advantages of IV locks include a reduction in the risk of circulatory overload, vascular irritation, bacterial contamination, cost of IV equipment, and an increase in patient comfort. Despite the benefits, IV locks require continual inspection and regular flushing. 8


The Infusion Nursing Standards of Practice state that "solution and frequency of flushing...should be established in organizational policies and procedures and should be in accordance with the manufacturer's guidelines."10(pS53) Heparin and normal saline solutions have been commonly used as IV lock irrigants. Despite its beneficial antithrombotic effects, heparin has been reported to contribute to the development of phlebitis, decrease platelet count, and cause of iatrogenic hemorrhage. 2 Researchers have indicated that flushing with normal saline prevents local tissue damage, drug incompatibilities, and iatrogenic hemorrhage, and it can also reduce the cost of maintaining peripheral devices. 9 The evidence obtained from a meta-analysis of randomized controlled trials (RCT) suggests that when compared to heparin, normal saline is equally effective in maintaining patency, thus reducing the need to move the PIV catheter to a new site, and in preventing phlebitis. 9


Although the literature has provided evidence of the type of solution to be used, information is limited related to the frequency of flushing and the volume of the irrigating solution to be used to prevent complications. The Infusion Nursing Standards of Practice indicate that the volume of the irrigating solution should be twice the volume capacity of the cannula and add-on devices. 10 Various volumes ranging from 5 to 10 mL have been recommended. 11 However, the literature provides little evidence upon which recommendations for an optimal volume can be based.


There is no consensus on the frequency for irrigating PIV catheters. Although no difference in catheter-related phlebitis has been reported in those catheters that have been regularly flushed and those that have not, 12 researchers continue to recommend that catheters be flushed after insertion 13 every 8 to 12 hours when the device is not in use and before and after the administration of medication. 9


The optimal method of maintaining patency of PIV catheter remains debatable, as some studies indicate that regardless of the volume of the irrigant used or the frequency of flushing, the technique used is most important. Recommended technique involves the creation of a turbulent flow achieved by the use of a pulsatile (push-pause) method and positive pressure withdrawal. 13 The size of the syringe used to irrigate PIV catheters is also another important factor that should be considered, as small syringes generate great pressure that could weaken or damage the PIV catheter. 10