RFDS South Eastern Section, Dubbo, NSW
Thoracic trauma such as rib fractures and penetrating injuries are commonly encountered in retrieval medicine. These injuries, and associated procedures (including thoracostomy) are painful to the point that ventilation may be compromised.
The mainstay of analgesia for these injuries is systemic agents such as opiates and ketamine, however these drugs also have significant side effects, including respiratory depression, sedation, and nausea.
The use of regional anaesthesia in thoracic trauma is common in hospital, yet its use in the pre-hospital setting is limited.
Here we describe two ultrasound guided regional techniques effective in thoracic trauma and used regularly in our service. Both can be performed on patients under spinal precautions, and who are anticoagulated.
Serratus anterior block:
Indicated for trauma anterior to the mid axillary line.
Anatomy: In the axillary fossa, the lateral cutaneous branches of the intercostal, intercostobrachialis, long thoracic and thoracodorsal nerves are found between the serratus anterior and latissimus dorsi muscles between the mid and posterior axillary lines
Sonoanatomy: A linear transducer is typically used in an AP orientation. The transducer is held in the axilla and moved posteriorly until the serratus anterior is identified deep to latissimus dorsi. An in-plane approach is then used to inject 20-30ml of local anaesthetic into the facial plane
Erector spinae plane block
Indicated for trauma to the posterior and anterior chest
Anatomy: The erector spinae muscle lies posterior to the transverse processes. Anaesthetic injected in between these structures diffuses anteriorly to the dorsal and ventral rami of the spinal roots.
Sonoanatomy: A linear transducer is used in a caudo-cranial orientation. The transverse process at the appropriate level is identified as a squared off acoustic shadow approximately 3cm lateral of the midline. The needle tip is directed onto the transverse process and anaesthetic is injected deep to the erector spinae muscle.