From the Research
You don't get flashback when performing a haematoma block because you are injecting local anesthetic directly into an existing blood collection (the haematoma) rather than into a blood vessel. When performing a haematoma block, typically for fracture reduction, you insert the needle into the fracture site where blood has already accumulated. Since you're not targeting a vessel but rather an existing pool of blood, there's no vessel to puncture that would result in flashback. The technique involves injecting lidocaine (typically 1-2% without epinephrine) directly into the haematoma surrounding the fracture, usually using about 5-10 ml depending on the size of the fracture. The local anesthetic then diffuses through the haematoma to anesthetize the periosteum and surrounding tissues. This differs from vascular access procedures where flashback confirms proper placement within a vessel. When performing a haematoma block, successful placement is often confirmed by decreased resistance to injection and patient reporting decreased pain at the fracture site within minutes of administration.
Key Points to Consider
- The haematoma block is a safe and effective technique for providing anesthesia in patients with distal radius fractures, as shown in a study published in 2020 1.
- The use of ultrasound-guided haematoma block has been shown to be a safe and effective alternative to procedural sedation and analgesia, with lower time to discharge and no late complications, as reported in a 2015 study 2.
- A combination of haematoma block and intravenous regional anesthesia can provide effective pain management and muscular relaxation for forearm fractures, as demonstrated in a 2016 case series 3.
- However, it's essential to be aware of potential complications, such as systemic neurological symptoms, which can occur due to systemic absorption of local anesthetics, as reported in a 2023 case report 4.
Recommendations for Practice
- Use the haematoma block technique with caution, monitoring patients for potential complications, such as systemic neurological symptoms.
- Consider using ultrasound guidance to improve the accuracy and safety of the haematoma block procedure.
- Be aware of the potential risks and benefits of combining haematoma block with other anesthesia techniques, such as intravenous regional anesthesia.