DAS Small Grant

Background
The incidence of failed intubation, or inability to place a breathing tube in the required position in the trachea, in children is reported as 0.08% in Europe and between 0.004 and 0.01% in the United States. This rare situation is life-threatening and needs timely rescue strategies to prevent hypoxia (low tissue oxygen levels) which can have disastrous consequences including cardiac arrest, stroke and death. The Difficult Airway Society recommend emergency cricothyroidotomy, or placement of a breathing tube through the skin of the neck directly into the airway, as a rescue strategy for children aged one to eight. The optimal technique for this procedure is currently unknown. Surgical techniques, using a knife and a larger conventional breathing tube, have higher success rates and less complications in animal studies but are slower than techniques using smaller needles. Using our previously reported measurements of children's cricothyroid membranes, the opening in the airway that is utilised for a cricothyroidotomy, a new device called the paediatric Cric guide has been developed. It is hoped to provide success rates and complication profiles at least similar to a surgical technique but with potentially improved speed. It is designed as a U shaped scalpel blade with two depth guards to limit its depth of insertion, thus preventing damage to the back wall of the airway. The U-shaped scalpel can be used to guide the breathing tube into the airway.

Aim
The aim is to evaluate and compare the success rates, speed of procedure and complication rates using both the Cric-guide device and a traditional surgical technique.

Methodology
This is a prospective randomised laboratory-based study. We will utilise 98 porcine cadaver airways with sheep skin covering to simulate a 20-40kg child's airway. A single investigator, a consultant paediatric anaesthetist with a special interest in paediatric airway research, will perform a cricothyroidotomy on each specimen using either the paediatric Cric-guide device or a traditional surgical technique (that is recommended by the difficult airway society). Each specimen will be randomised to one of the techniques. After the procedure successful placement of the breathing tube into the airway will be determined by dissection of the specimens. This is the primary outcome. Secondary outcomes include time and complications. We will measure time from initiation of the technique to placement of the breathing tube into the airway, as perceived by the investigator. Complications including damage to walls of the airway will also be determined on dissection.

Expected Outcomes
We expect that the success rates of the paediatric Cric-guide will be higher than that of the surgical technique and that time to placement will be shorter. We expect that complication rates should also be reduced due to the customised dimensions and depth guards.

Implications
We hope to validate a custom-made paediatric cricothyroidotomy device that combines improved success rates and speed compared to the surgical technique.