Should You Increase IV Flushes?
No, you should not routinely increase IV flush frequency beyond once daily for peripheral IV catheters, as evidence demonstrates that once-daily saline flushes maintain patency as effectively as more frequent flushing without increasing complications. 1
Evidence for Flush Frequency
Peripheral IV Catheters
- Once-daily saline flushing is non-inferior to twice-daily flushing for maintaining peripheral IV catheter patency in children aged 1-17 years, with occlusion rates of 4.5% vs 7.6% respectively (p=0.21). 1
- The 24-hour flushing interval showed a +3.1% advantage in catheter patency (95% CI -1.6% to 7.7%), meeting non-inferiority criteria. 1
- Catheter-related complications were not different between once-daily (9.5%) and twice-daily (12.1%) flushing groups (p=0.42). 1
- Reducing flush frequency decreases costs, nursing time, labor, and unnecessary catheter manipulation that causes distress in patients. 1
Central Venous Catheters
- For central venous catheters in pediatric patients, practice varies widely from twice daily to once every three weeks, with no strong evidence supporting any specific frequency. 2
- A randomized crossover study in children found no difference in blocked catheters or complications comparing twice-daily heparin flushes with once-weekly saline. 2
- In adult cancer patients with implantable venous access devices, flushing before and after blood sampling, at the end of IV therapy, or every eight weeks if not in use showed no differences in port malfunction or sepsis. 2
Flush Solution and Technique
Solution Selection
- Normal saline is as effective as heparin for maintaining catheter patency in most clinical situations. 2, 3
- For central venous catheters, if heparin is used, low concentrations (0.5-1.0 U/mL) are recommended to avoid lipid emboli formation. 2
- There is weak evidence that heparin flushing reduces occlusion but no evidence it reduces bloodstream infections. 3
Flush Volume and Syringe Size
- The most commonly used flush volume is 5 mL of normal saline. 4
- Larger syringe sizes (≥10 mL) generate lower pressure and are preferred to prevent catheter damage. 4
Flush Technique
- Push-pause (pulsatile) flushing technique creates turbulent flow that may be more effective at clearing fibrin deposits than continuous pressure flushing. 5
- Only 23.4% of nurses use the push-pause technique, while 31.2% use continuous pressure, indicating inconsistent practice. 4
Total Fluid Accounting
When considering flush frequency, remember that all fluid sources must be included in daily fluid balance calculations: 2, 6
- IV fluids and blood products
- All IV medications (infusions and boluses)
- Arterial and venous line flush solutions
- Enteral intake
This is critical to prevent fluid creep and avoid fluid overload, which is associated with prolonged mechanical ventilation and increased length of stay. 2
Common Pitfalls to Avoid
- Do not increase flush frequency without evidence of catheter dysfunction, as more frequent manipulation increases infection risk and patient discomfort. 1
- Avoid intermittent saline flushes during hemodialysis in patients receiving reduced anticoagulation, as this paradoxically increases coagulation markers and visible clotting. 7
- Do not ignore flush volumes when calculating daily fluid balance in critically ill patients, especially those with heart failure, renal failure, or hepatic failure requiring fluid restriction to 50-60% of calculated maintenance. 2, 6
- Ensure nurses are trained in proper flush technique (push-pause method) rather than simply increasing frequency. 4, 5
Monitoring Requirements
For patients receiving IV therapy with regular flushes: 2, 6
- Daily assessment of fluid balance and clinical status is mandatory
- Regular electrolyte monitoring, especially sodium levels
- Strict intake/output recording including all flush volumes
- Daily weights to detect fluid accumulation
- Clinical examination for signs of fluid overload (edema, ascites, pleural effusion)