The ability to administer peripheral nerve blocks in the ED has the potential to provide fast and direct analgesia with less systemic side effects compared to parenteral medications. When administered by an experienced provider, studies have shown that peripheral nerve blocks can provide reliable and prolonged analgesia. There is also evidence that nerve blocks can decrease overall length of stay in the emergency department for specific procedures. While there are various peripheral nerve blocks that are appropriate in the ED setting, there are three in particular that are further supported by evidence:
- Interscalene Block
- Regional Nerve Blocks of the Hip
- Nerve Blocks for Headache
The clinical use of these blocks is discussed here. Specific details and step by step instructions are described in the reference articles below.
The Interscalene Block
The main indications for this block include:
- Instant analgesia for upper-extremity fractures (proximal humerus, midshaft humerus)
- Exploration, debridement and repair of large upper extremity wounds or abscesses
- To facilitate manipulation and reduction of upper extremity injuries like shoulder dislocations
The interscalene block should be administered using ultrasound guidance if it is performed in the emergency department.
|From Blaivas et al. Ultrasound view of Brachial Plexus when performing an interscalene block|
This block is contraindicated in patients with lung pathology and a low respiratory reserve (ex, COPD) as it carries a risk of phrenic nerve palsy. A pneumothorax can also occur if the block is performed at the level of the larynx.
The benefit of this block in the ED has been previously documented. A prospective comparison trial by Blaivas et al. comparing ultrasound guided interscalene nerve block to procedural sedation showed a decreased length of stay in the department from an average of 177 minutes with sedation to 100 minutes in the peripheral nerve block group.
Both groups achieved equivalent patient satisfaction and pain reduction scores and there was no difference in reported complications. This study had a sample size of 42 with 21 patients in each group. The blocks were performed by ED physicians with 2 years and at least 10 nerve blocks of experience.
The block is not difficult to perform either. A case report from New Delhi by Bhoi et al. demonstrated that after a single seminar ED providers were able to provide effective analgesia to an upper extremity injury after a crush injury using the interscalene block.
Regional Nerve Blocks of the Hip
A recent systematic review out of Ottawa by Ritcey et al. compared the effectiveness of three regional nerve blocks of the hip. It found that the femoral nerve block, 3-in-1 femoral nerve block and the fascia iliaca block all provided reductions in pain and the need for IV opiates. The main indication for this block would be fractures to the femur and injuries to the patella and its tendons.
Contraindications are typical and include infection over the injection area, patient refusal or allergy to local anesthetic. Patients at risk for compartment syndrome should also be selected cautiously since they may not reliably have increased pain after the block.
Mouzopoulos et al. showed in a randomized placebo-controlled study that a fascia iliaca block resulted in decreased incidence, severity and duration of delirium when compared to placebo in patients with hip fractures. The study included 213 patients of which 102 received the fascia iliaca block consisting of 0.3mL/kg of 0.25% bupivacaine on admission and daily until they had surgery for their fracture.
Another study by Callear et al showed that implementation of an institutional treatment pathway to provide fascia iliaca blocks to hip fracture patients lowered post-operative delirium by over 50%.
As more prospective studies examining the effects femoral nerve blocks have on delirium and mortality are published, the use of the block will likely increase.
(Video from Anatomy for Emergency Medicine by Dr. Andy Neill)
Nerve blocks for headaches