Air or saline to fill breathing tube cuffs for ventilated children during flight

Tracheal tubes used for mechanical ventilation in critically ill paediatric patients are often fitted with a cuff. Cuffed tubes are less likely to be used in younger patients, but their use becomes increasingly likely over the age of one year. The cuff is inflated with air following endotracheal intubation. Cuff pressures are measured as part of standard care in intensive care units, as a high pressure in the cuff entails a risk of damaging the tracheal mucosa. Blood flow in the tracheal wall is compromised at cuff pressures greater than 30cmH2O and ceases at the critical perfusion pressure of 50cmH2O. Aeromedical transport introduces a new risk, as during ascent there may be rapid change of the relative pressures of the gas in the cuff and the surrounding atmosphere, leading to very high pressures inside the cuff. The intervention group in this study will have the cuff of the tracheal tube filled with air. The intervention will last for the duration of the aeromedical transport, which will be between 1 and 3 hours. The intervention will be delivered by the transport team, which will consist of a PICU registrar and a PICU transport nurse. A log will be kept of which patients eligible for transport are randomised to the intervention or to standard care.