How To Be A Better Mountain Medic ... Fascia Iliaca Block

Posted by Jeremy Windsor on Jun 21, 2019

One of the best bits about being an anaesthetist is the chance to perform nerve blocks. There's something very satisfying about having a practical skill that can treat pain quickly and effectively. One of my favourite blocks is the fascia iliaca compartment block (FICB) and recently, whilst working on an update for the Wilderness Medical Society's "Practice Guidelines For The Treatment of Acute Pain In Remote Environments"*, I came across a systematic review that looked at the safety and effectiveness of the block in the pre-hospital environment (1).

But before we examine the paper, let's take a closer look at the block itself. The fascia lata and iliaca are two bands of connective tissue that overlie the muscles and nerves of the thigh. In a FICB, local anaesthetic is injected under the fascia iliaca and in close proximity to a number of sensory nerves that supply the area.

A cross section of the right thigh distal to the groin crease. The distribution of local anaesthetic following a FICB is shown in yellow. The femoral, lateral femoral cutaneous and branches of the obturator nerve are blocked. This makes the FICB a highly effective way of providing analgesia to those who've suffered significant hip or thigh injuries. 

The injection point of the FICB is easy to identify - a line is drawn between the anterior superior iliac spine (ASIS) and the pubic tubercle (PT). This is divided into thirds and a needle is inserted, perpendicular to the skin, 1cm below the point where the lateral and medial thirds meet. By advancing the needle slowly two clear "pops" are felt. These represent the needle advancing through the fascia lata and fascia iliaca. At this point local anaesthetic is injected. Alternatively, ultrasound can be used to follow the needle tip through the fascia iliaca and visualise the spread of local anaesthetic towards the nerves.

The injection site for the FICB - Divide a line between the ASIS and PT into thirds and insert a needle, perpendicular to the skin, 1cm below the point where the lateral and medial thirds meet.

An excellent demonstration of the FICB can be found here...

The systematic review identified 7 papers that studied a total of 254 patients who received a pre-hospital FICB. The papers varied enormously - from a randomized controlled trial to a series of prospective and retrospective observational studies and even a case report! Nevertheless, collectively they reveal for the first time how FICB's performed by experienced operators in the pre-hospital environment can lead to significant reductions in pain amongst patients with femoral fractures. Importantly, in many instances, pain relief was rapid. In an RCT comparing FICB with intravenous morphine (2.5mg every 2 minutes up to 0.5mg/kg), the mean pain score fell from 10/10 to 3/10 within 15 minutes in the FICB group compared to a reduction from 9/10 to 7/10 in those receiving morphine (2). These results were supported by two papers identifying high levels of patient satisfaction in patients who'd received a FICB. 

The systematic review also showed that the block was safe and crucially, did not delay the patient's arrival at hospital. Amongst 254 FICB's only a single adverse event was reported. This was a brief episode of tachycardia, hypertension and headache that resolved quickly without treatment. In the RCT previously described, there was no difference in the time spent at the scene or during transportation (2).

This encouraging systematic review provides the first overview of research into FICB use in pre-hospital care.  In the future, could the FICB be a regular part of pre-hospital care? Let me know your thoughts!

(1) Hards M et/al. Efficacy of pre-hospital analgesia with Fascia Iliaca Compartment Block for femoral bone fractures: a systematic review. Prehosp Disaster Med 2018;33(3):299-307.

(2) McRae PJ et/al. Paramedic-performed Fascia Iliaca Compartment Block for femoral fracture: a controlled trial. J Emerg Med 2015;48(5):581-589.

Let me know if you need a copy of either paper.

*The 2014 update can be found here.

2 thoughts on “How To Be A Better Mountain Medic ... Fascia Iliaca Block

John Laughlin commented 4 weeks, 1 day ago
How do you mitigate for severe local anaesthetic toxicity? Seen it happen when block given in ED ramping area while awaiting ambulance offload. Things went downhill pretty quickly and I'd be nervous about that happening out in the sticks!
Stuart commented 4 weeks, 1 day ago
A tutorial or workshop in module 1?

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