Comparison of Average volume assured pressure support (AVAPS) and standard bilevel modes of non invasive ventilation in children

Crossover trial design. Participants are randomised to receive either standard pressure support ventilation followed by AVAPS or AVAPS followed by standard pressure support ventilation. The comparator is standard bilevel pressure support ventilation. The intervention is the randomisation of the order AVAPS ventilation is given to the patients whilst being blinded to the mode. Automated volume assured pressure support is currently only used in patients who don't tolerate standard bilevel pressure support. AVAPS is delivered in the same way as standard pressure support ventilation - via a nasal mask, sometimes an Oro-nasal mask. AVAPS and standard pressure support ventilation both provide 2 pressures - an inspiratory pressure and an expiratory pressure. In standard therapy, these are set and don’t change throughout the night. In AVAPS a range of pressures are set and the machine alters the pressure provided according to the patient’s breathing through the night in order to achieve a targeted tidal volume. There is no washout period between modes of ventilation. The same ventilator will be used throughout, the mode will be altered. Initiation and titration of each mode of ventilation will take place at the Sydney Children's Hosptial sleep lab by and experienced sleep scientist with at least 5 years experience. Patients attend the hospital in the afternoon and undergo a titration sleep study overnight. They also perform a number of respiratory function tests on the afternoon before the titration study and the morning following the study. These take approximately 1 hour. The patient will continue on each mode of ventilation at home for 3 months. The ventilator will be used everynight throughout sleep. Adherence and actual time used is an outcome measure of the study. Adherence data will be downloaded from the machine. They will be reviewed at their standard follow up appointments. They will recieve a phone call at 1 week, 1 month and 3 months post commencement of each mode to answer questionnaires.