Prehospital lateral canthotomy
- Correspondence to Dr Christopher Hill, Sydney Rescue Helicopter Base Bankstown Hospital, Drover Road, Sydney, NSW 2200, Australia;
Contributors CH performed the procedure and wrote the case. CR, AT and BB edited and assisted in obtaining consent and images. MB assisted during the procedure.
- Accepted 22 May 2012
- Published Online First 2 July 2012
- prehospital care
- helicopter retrieval
- critical care transport
- intensive care
We present the case of a 21-year-old patient who required a prehospital lateral canthotomy following a penetrating injury to the head. This, the first recorded prehospital case, highlights the importance of this simple, potentially sight saving procedure and why it should be in the armamentarium of all prehospital emergency physicians.
Our patient was treated by the physician staffed Greater Sydney Area Helicopter Emergency Medical Service (GSA-HEMS) from its satellite base 100 km South of Sydney, Australia. GSA-HEMS covers the state of New South Wales providing medical teams for prehospital trauma response and interhospital critical care retrieval.
A GSA-HEMS medical team was called to the home of a previously healthy 21-year-old female subject who had reportedly been shot. On arrival, the team found the patient lying in the front room of her house being attended to by the local paramedics. On examination, there was a single entry wound in the midline of the patient's forehead and her left eye was swollen. Given the hostile environment, the patient was moved outside to an ambulance for further assessment.
The primary survey revealed a patent airway, normal respiratory rate, pulse and blood pressure. Glasgow coma score was 12/15 (E2, V4, M6) with no motor asymmetry. During examination, her left eye was noted to be tensely swollen with marked proptosis. The pupil was mid-dilated and unreactive. Her right pupil showed a normal reflex to direct light. During this initial assessment, the patient became increasingly distressed and agitated for which an rapid sequence induction (RSI) was performed.
Following the RSI, a lateral canthotomy was performed for suspected severe retrobulbar haemorrhage. The skin at the corner of her eye was crimped, using a haemostat, from the lateral apex of the eyelid to the anterior aspect of the bony orbital rim, approximately 1 cm. Following this, the skin was cut which in itself released some tension and allowed the herniation of significant corneal oedema. The lower eyelid was then retracted inferiorly, revealing the inferior canthal ligament. This was then also divided. The procedure took approximately 2 min. The patient was then packaged and flown to the nearest major trauma centre in Sydney, a 30 min flight.
Her initial CT (figure 1) showed a 0.22-inch calibre bullet that had traversed the orbital fossa and remained in situ between the temporal and parietal lobes. There was significant oedema and bleeding to the left orbital region. She underwent an emergency craniectomy and following an uneventful recovery was discharged from hospital neurologically intact. There was significant damage to the optic nerve leading to a permanent loss of sight in the left eye.
Emergency lateral canthotomy is a well-documented procedure1–4 that can be sight saving in cases of retro orbital haematoma. The overall incidence of this condition is low; however, it is thought the potential for permanent blindness is in the order of 50% if left untreated.1 The initiation of retinal ischaemia occurs as the pressure rises in the orbital fossa and it is thought that permanent retinal damage will occur after around 60–120 min of the orbital pressure exceeding 40 mm Hg.1 ,2 Emergency ophthalmological consult is often not possible during this timeframe, especially when combined with long prehospital transfer times. Therefore, this procedure is most likely to be meaningfully performed in the prehospital or emergency department phase of patient care.
Commonly accepted indications for canthotomy include decreased visual acuity, high intraocular pressures (>40 mm Hg) and proptosis most commonly in association with local trauma. The condition has also been described postoperatively and with rupture of vascular anomalies.4 Other described indications include ocular pain, a relative afferent pupillary defect, cherry red macula and ophthalmoplegia.
GSA-HEMS physicians carry the equipment for this procedure and undergo training for canthotomy using a porcine model during induction training. This teaching technique has been previously studied and found to provide high levels of skill confidence.5 Given that this procedure is unlikely to be undertaken regularly, frequent training and mental preparation are critical to ensure the procedure is undertaken appropriately and quickly.
Lateral canthotomy can be performed in the prehospital environment. Prehospital emergency physicians should be trained and equipped to perform this potentially sight saving surgical procedure.
All work for the Greater Sydney Area Helicopter Emergency Medical Service.
Competing interests None.
Patient consent Obtained.
Ethics approval Ethics approval was provided by Ethics Committee Royal Prince Alfred Zone - Sydney. This is the ethics committee used by the Ambulance service of NSW.
Provenance and peer review Not commissioned; internally peer reviewed.