What is the preparation of heparinized (Heparin) saline solution?

From the Guidelines

Heparinized saline solution is typically prepared with a concentration of 10-100 units of heparin per milliliter of normal saline (0.9% sodium chloride), with 10 units/mL being the most commonly recommended concentration for maintaining patency of intravenous catheters. To prepare this solution, one can withdraw 0.1 mL of 1000 units/mL heparin and add it to 9.9 mL of normal saline to make a 10 mL solution, as suggested by general medical practice, although the exact preparation method may vary depending on the institution's policy 1. The use of heparinized saline is based on the principle of preventing blood clot formation through heparin's anticoagulant properties, which inhibit thrombin and factor Xa in the coagulation cascade, thus preventing fibrin formation and subsequent clotting in catheters 1. Key points to consider when preparing heparinized saline solution include:

• Always label the prepared solution clearly with the concentration, date, time of preparation, and your initials.
• Discard any unused solution after 24 hours to maintain sterility and potency.
• Check your institution's policy regarding heparinised saline preparation and use, as practices may vary.
• The low concentration used for line flushing generally doesn't produce systemic anticoagulation effects, but it is crucial to follow the recommended guidelines and manufacturer's instructions for specific devices, such as implanted ports or open-ended catheter lumens 1. It is also important to note that the effectiveness of heparinized saline in maintaining catheter patency compared to saline alone is still a topic of discussion, with some studies suggesting that intermittent flushing with heparin is no more beneficial than flushing with normal saline alone 1. However, manufacturers of implanted ports or opened-ended catheter lumens recommend heparin flushes for maintaining catheter patency, especially when devices are infrequently accessed 1.

From the FDA Drug Label

Each mL of the 1,000 units per mL preparation contains: 1,000 USP Heparin units (porcine); 9 mg sodium chloride; Water for Injection q.s. Made isotonic with sodium chloride.

The preparation of heparinized (Heparin) saline solution is a sterile solution of heparin sodium derived from porcine intestinal mucosa, standardized for anticoagulant activity, in water for injection, made isotonic with sodium chloride. The solution contains 1,000 USP Heparin units (porcine) and 9 mg sodium chloride per mL. 2

From the Research

Preparation of Heparinized Saline Solution

The preparation of heparinized saline solution varies depending on the intended use and the patient's condition.

• Heparin concentrations ranging from 1000 to 10,000 U/ml have been used in some centers 3.
• A concentration of 10 U.S.P. units of sodium heparin per milliliter of normal saline solution has been shown to maintain patency of heparin-locks without affecting the clotting time, prothrombin time or activated partial thromboplastin time 4.
• Heparinized saline with concentrations of 1,000 IU/l and 5,000 IU/l are commonly used in arterial vascular interventional radiology 5.
• The use of heparin lock at 1000 U/ml is recommended for maintaining patency of tunneled central venous catheters for dialysis, with higher concentrations reserved for patients who have evidence of catheter occlusion or thrombosis 3.

Administration and Monitoring

• The injected volume of heparinized saline solution should not exceed the internal volume of the catheter 3.
• Platelet counts should be monitored every 2-3 days throughout heparin therapy, particularly during days 4-14 when heparin-induced thrombocytopenia (HIT) is most likely to develop 6.
• The use of heparinized saline solution should be carefully considered, as it may increase the risk of HIT and other complications 7, 6.