DAS Project Grant
Bench study comparing three different emergency tracheal
access devices in a porcine model
Dr Wendy King
Background:
Can't intubate, can't ventilate (CICV) is a life threatening situation arising from failure to provide oxygen to an anaesthetised patient, which can result in catastrophic brain injury or death. Fortunately, few anaesthetists expect to experience this scenario more than once in their careers (1:50,000 general anaesthetics). Despite this, it is imperative that we are optimally prepared for such an eventuality. The appropriate emergency equipment must be available to permit life-saving cricothyrotomy (a procedure whereby a hole is made in the neck, through which the patient can breathe). Various devices have been developed to carry out cricothyrotomy over the years, and these include narrow-bore needles, wire-guided techniques, and pre-assembled cannula-over-needle kits. A simple surgical technique is offered as an alternative within the Difficult Airway Society CICV guidelines but of all these, there is little consensus as to which is the quickest and safest.
The Difficult Airway Society (DAS) and the Royal College of Anaesthetists (RCoA) recently published the Fourth National Audit Project, revealing an alarmingly high failure rate for emergency narrow-bore cannula cricothyrotomy amongst anaesthetists (approximately 60%). As a procedure, it is fraught with potential hazards, and even when successful, subsequent oxygenation is not without risk.
VBM has recently introduced the Surgicric1 into the market place. This new device looks to provide a simple pre-prepared 'all-you-need' surgical cricothyroidotomy kit which may bridge the divide between needle cricothyroidotomy and a surgical technique. We will compare this further with the Melker set which employs the seldinger technique of threading a cricothyrotomy tube over a wire, and although potentially time consuming, is familiar to anaesthetists. This was rated higher than the surgical technique in a recent study.
Aims:
We plan to carry out a bench study, comparing 3 methods of securing emergency tracheal access on a porcine airway.
Methodology:
We will perform a randomised cross-over study to investigate the surgical cricothyroidotomy, Melker Emergency Cricothyrotomy, and VBM Surgicric1 devices.
Having excluded the requirement for Research Ethics Approval, anaesthetists (n=25) will be recruited and consented. They will receive a standardised 5 minute demonstration of each technique, and permitted a single practise insertion into a manikin neck. They will then perform cricothyroidotomy on a fresh pig larynx with each method in randomised order. The pig larynx and windpipe have been used in previous studies, and found to provide a realistic anatomical representation of the human airway. It will be housed in an airway training manikin, and covered in pig skin.
Outcomes to be measured include success rate, insertion time, immediate complications, and personal preference.
Outcomes:
We expect one technique to be the fastest to insert. It is possible that such a device is also the most user-friendly, and favoured by the participants.
Implications:
Data acquired will inform anaesthetists on a national scale of the performance of the as yet untested Surgicric1 device. If superior to other devices, it could improve outcomes of CICV scenarios, and save lives.
