Epidural Catheters

Neuraxial analgesia can be a very effective pain treatment in the injured warfighter, but special care must be taken to ensure that it is provided safely. Standard preservative free local anesthetics include ropivacaine and bupivacaine. The standard medication for aeromedical evacuation is 0.2% ropivacaine with sufficient volume for 3 days. Patients should be on stable doses of infusions prior to Aeromedical Evacuation (AE) transportation. The risk/benefit of epidural placement must be considered in the injured combat casualty who is also at risk for venous thromboembolic events. While all antiplatelet and anticoagulant medications increase the risk of bleeding, unfractionated heparin (UFH) and low molecular weight heparin (LMWH) use in patients undergoing epidural anesthesia greatly increases the risk of epidural hematoma, which can lead to paralysis. The APMS should maintain and provide input for standing orders to include:

1. All catheters should receive a 3 ml test dose of local anesthetic containing at least 1:400,000 epinephrine.

2. LMWH and UFH use in patients undergoing epidural anesthesia increases the risk of spinal or epidural hematoma, which may cause long term or permanent paralysis. We recommend against the use of LMWH in AE patients given the increased motion of delivery catheters during patient transport and resulting increased risk for spinal and epidural hematoma formation.

3. Before placement of an epidural catheter:

- Prophylactic LMWH should be held for at least 12 hours.
- Low-dose prophylactic UFH should be held for 4-6 hours.
- Therapeutic LMWH should be held for at least 24 hours.
- Therapeutic UFH should be held for at least 24 hours and the coagulation status assessed.

4. With an epidural catheter in place:

- The maximum recommended prophylactic dose of LMWH is 40mg SQ daily.
- The maximum recommended prophylactic dose of UFH is 5000U SQ TID.
- The initial dose of once daily prophylactic LMWH should not be given until 12 hours after catheter placement. Subsequent daily doses of prophylactic LMWH should start no sooner than 24 hours after the first dose.
- The initial dose of low-dose prophylactic UFH can be given immediately after catheter placement.
- Twice daily dosing of prophylactic LMWH, therapeutic UFH, and therapeutic LMWH are not recommended.

5. Before epidural catheter removal:

- Prophylactic LMWH should be held for at least 12 hours.
- Low-dose prophylactic UFH should be held for 4-6 hours.

6. After epidural catheter removal:

- Administration of prophylactic LMWH should be held for at least 4 hours.
- Administration of low-dose prophylactic UFH can occur immediately.
- Administration of therapeutic LMWH should be held for at least 4 hours
- Administration of therapeutic UFH should be held for 1 hour.

These recommendations are consistent with the most recent ASRA (American Society of Regional Anesthesia) guidelines for the prevention of epidural hematoma.2

Note: Given that our patients are transported through a spectrum of care and across thousands of miles, the implementation of regional anesthesia should be integrated throughout the trauma system and must be safe and effective. An anesthesia provider is responsible for the initial placement and dosing of an epidural catheter. Only members of the APMS can change the dosing or infusion rate.

Appendix G is a summary of the ASRA guidelines as they relate to use of LMWH in combat casualties. The ASRA guidelines were originally developed for use of LMWH in the perioperative course.

Additionally, these recommendations change on a frequent basis; https://www.asra.com/ should be consulted for the most current recommendations.