From the Guidelines
A saline lock is a device that is flushed and locked with saline solution when not in use, as recommended by the ESPEN guidelines on parenteral nutrition 1. This recommendation is based on the fact that most central venous access devices for parenteral nutrition can be safely flushed and locked with saline solution when not in use, with a Grade B recommendation 1. The use of saline lock is beneficial for maintaining catheter patency and preventing occlusion from blood clots or drug precipitation. Some key points to consider when using a saline lock include:
- Flushing the catheter with saline before and after medication administration, or at least every 8-24 hours if not in active use 1
- Using sterile 0.9% sodium chloride for injection to flush and lock catheter lumens that are in frequent use, with a Grade A recommendation 1
- Avoiding the use of heparinized solutions unless recommended by the manufacturer, such as for implanted ports or open-ended catheter lumens that are scheduled to remain closed for more than 8 hours 1 The saline lock device typically consists of a short catheter inserted into a peripheral vein, with an attached hub that can be accessed with a syringe or IV tubing when needed. Overall, the use of a saline lock provides immediate venous access for medication administration while reducing complications associated with continuous IV therapy, such as fluid overload 1.
From the Research
Definition of Saline Lock
- A saline lock is a device used to maintain the patency of intravenous (IV) catheters when they are not in use 2, 3.
- It involves flushing the catheter with a saline solution to prevent occlusion and maintain its functionality.
Purpose of Saline Lock
- The primary purpose of a saline lock is to prevent the catheter from becoming occluded, which can lead to complications such as infection or thrombosis 4, 5.
- Saline locks are also used to maintain the patency of central venous catheters (CVCs) in adults, although the effectiveness of heparin versus normal saline is still a topic of debate 4, 5.
Comparison with Heparin
- Studies have compared the use of heparin versus normal saline for locking CVCs, with some showing no significant difference in preventing occlusion or maintaining catheter patency 2, 4, 5.
- However, other studies suggest that heparin may be more effective in preventing occlusion, although the evidence is not conclusive 5.
Use in Different Populations
- Saline locks are used in various populations, including adult cancer patients 2, pediatric patients 6, and patients in intensive care units (ICUs) 5.
- The use of saline locks in these populations is aimed at maintaining catheter patency and preventing complications associated with catheter occlusion.
Key Findings
- A study published in 2020 found that saline locks were as effective as continuous infusion in maintaining peripheral IV catheter access in children 6.
- Another study published in 2022 found that heparin may have little or no effect on catheter patency duration, although the evidence was of low certainty 5.