Modified Endotracheal Balloon Dilator to Improve Oxygenation During Airway Procedures in Children With Tracheal Stenosis

This study is a prospective, single arm, observational study of patients at Red Cross War Memorial Children's Hospital receiving treatment for laryngotracheal stenosis using a modified tracheal dilatation balloon. The tracheal balloon dilatation procedure is clinically well-established and is standard practice in the study institution. In this study, a modified, improved tracheal balloon will be used to treat patients. Data to be collected during the procedure include measurement of the stenotic segment prior to and after dilatation, using both the modified Myer-Cotton grading system and sizing the stenosis using endotracheal tubes diameter, documenting the site of the stenosis (distance from vocal cords), periprocedural oxygen saturation nadir (using plethysmography) and heart rate. All other procedures will be as per routine care. Each procedure will be monitored by a senior anaesthetist who is not a member of the research team. Their role will be to ensure the safety of the patient.

The tracheal balloon dilatation device consists of a catheter tube which has an inflation port at its proximal end and a balloon at its distal end. The balloon is provided in a narrow, folded condition to allow entering and traversing the stenotic portion of the airway. As with all tracheal dilatation balloons, when inflated with an inflator equipped with a pressure manometer, the device generates an outward radial force to dilate the stenotic portion of the airway. The balloon differs from previous devices used for dilatation of tracheal stenosis in that it is modified to have a large central channel when inflated, which allows gas flow through the balloon.

All materials in the device are medical grade and sourced from specialist medical suppliers. The balloons specifically have undergone biocompatibility testing according to ISO 10993-1 (Biological testing of medical devices) and passed all tests. Safety of the devices has been rigorously demonstrated through in vitro bench testing, and balloons have been shown to survive a minimum of 10 inflations to rated burst pressure without bursting. The devices are manufactured by a facility experienced in production of endovascular balloons, in an ISO 14644 Class 7 compliant clean-room in a manufacturing facility that has a certified ISO 13485 quality management system. The balloons are tested as part of an ongoing quality control process, to ensure that tight tolerances are maintained in terms of wall thickness, nominal diameter and rated burst pressure. Furthermore, every tracheal balloon device will have been pressure tested to 16 atm before being used, to ensure that no leaks are present.

The device has been assessed in three previous studies, in manikin, animal and adult human use settings. The studies proved that it is possible to adequately ventilate patients through the modified balloon dilation device. There was no incident of arterial desaturation below 90%. No serious adverse events were recorded.

The study will be conducted over a 12 week period, with an average of 1 patient per week undergoing the procedure at the study site. Recruitment is thus estimated at 12 patients (not procedures).