II. Mechanism
- Blood is a procoagulant
- When injected within the epidural space, blood collects on the dural membrane inner surface
- Injected blood forms a clot, effectively plugging a CSF Leak (Spinal Headache cause)
III. Technique
- Patient's blood (20-30 cc) is collected using sterile technique
- Epidural needle inserted into epidural space
- Insertion site at the site of the prior Lumbar Puncture (leak site) or below that site
- Needle is inserted through ligamentum flavum (crunchy) and then a pop is felt
- Inject a small amount of saline or air while advancing needle
- Resistance is lost when epidural space is entered
- Some providers prefer injecting air, as saline may be confused with CSF
- CSF flow on insertion indicates the needle has punctured the dura (too deep)
- Dural puncture complicates >1% of blood patches (even in experienced hands)
- Do NOT inject blood into the subdural space (risk of arachnoiditis, infection)
- Patient's blood (20-30 cc) is injected via epidural needle into epidural space
- Blood dissipates at least 9-10 levels while patient is in the supine position
IV. Adverse Effects
- Back Pain (35% of cases)
- Dural Puncture (>1%)
- Subdural Injection of Blood
- Risk of arachnoiditis or infection
-
Recurrent Headache due to loss of blood patch (40% of cases)
- Patients should avoid straining, bending and heavy lifting after the blood patch
V. References
- Claudius and Darras in Herbert (2018) EM:Rap 18(11):12-3