One of the potentially life-saving interventions that a HEMS service can offer is pre-hospital thoracotomy in the setting of penetrating chest trauma and cardiac arrest at the scene.
Pre-hospital thoracotomy is well described in the literature, with good outcomes reported. The London HEMS group recently published a case series of 71 patients who underwent pre-hospital thoracotomy following stab wounds to the chest with cardiac arrest at the scene. Of these patients, 13 survived, and 11 had a good neurologic outcome.
The main issue with pre-hospital thoracotomy for the Auckland HEMS service is that while this intervention may be lifesaving, the frequency with which we would expect to have to perform it is extremely low, and therefore training and skills maintenance are extremely difficult. (Having said this, one of the Auckland HEMS doctors encountered a patient with penetrating chest trauma on his first ever (!) HEMS job, and was at most several minutes away from dealing with his patient arresting and the indication for prehospital thoracotomy being present. This patient was moribund on arrival to hospital, and underwent an ED thoracotomy prior to transfer to OR. The outcome in this case was excellent.)
The vast majority of significant trauma that occurs in the New Zealand region occurs via a blunt mechanism. The Auckland Hospital Trauma Service, who maintain an extensive database of trauma cases presenting to Auckland Hospital, published a review in 2011 of penetrating thoraco-abdominal trauma, which revealed that between 2003 and 2008 there were only 42 cases.
As a result of this, thoracotomy in ED in Auckland is an extremely rare event – probably about one per year, and these are usually performed by the surgical service rather than an ED physician. Such low frequency means that there is not really a measurable standard of care amongst ED physicians for ED thoracotomy, let alone pre-hospital thoracotomy. Mr Ian Civil, the director of the Auckland Trauma service, argued in a 2010 editorial in Emergency Medicine Australasia that the availability of surgical services in larger hospitals means that it does not make sense to train ED physicians in thoracotomy.
Considering prehospital thoracotomy in the context of the Auckland HEMS service, the situation is completely different. To load a patient at the scene, make even a short flight, and deliver the patient to a resuscitation area with a waiting trauma team, at least 15 minutes is required. If the patient has ANY signs of life at the scene, I suspect most of us would opt for immediate transport, but if the patient arrests at the scene, without a thoracotomy they have no chance of survival given the transport time to ED.
With this in mind, the Auckland HEMS service needs to consider how we would train for this eventuality and how the procedure would be performed in practice. Although several members of our team have prior experience in prehospital thoracotomy (one worked in prehospital care in Glasgow!), most have very little experience aside from very occasionally assisting the surgical service in the resuscitation area.
Rather than reinventing the wheel, we could start by using resources that have been created by services far more experienced in this than us.
The London HEMS service has posted their thoracotomy S.O.P. on their website. It is the best summary of the procedure I have encountered that reflects the sort of equipment we carry (not a rib spreader to be seen). An open access pdf from EMJ by some of the same authors is here, and contains additional commentary and photos.
London HEMS training for thoracotomy includes one-on-one training on techniques for opening the chest and internal cardiac massage, including use of video footage and a dedicated thoracotomy mannequin. While it would be difficult to justify obtaining a dedicated thoracotomy mannequin currently (our general purpose low fidelity mannequin is in dire need of replacement first!), between the HEMS group and the Auckland Surgical Services we have individuals with the necessary experience to provide tuition to the rest of us.
In the meantime, video resources are available here:
Standard L side thoracotomy, showing opening of the intercostal muscles with scissors, and vertical incision of the pericardium between two sets of forceps
Standard L side thoracotomy with audio explanation on a cadaver
Video demonstrating clamshell incision, cutting across sternum, and opening chest. Note the London HEMS S.O.P. includes the thoracotomy incisions being extended to the posterior axillary line bilaterally in order to provide good exposure without the need for rib retractors
Second half of this clip shows part of the London HEMS training in prehospital thoracotomy
Full text pdfs for this post are available here (secure area limited to ADHB staff only – ADHB has subscription access for staff to these journals through the Philson Library at the University of Auckland School Of Medicine)