NAVA in Infants With Acute Viral Bronchiolitis: A Feasibility Study

This exploratory intervention feasibility study aims to evaluate the use of a novel mode of ventilation known as Neurally adjusted ventilatory assist (NAVA) in infants with acute viral bronchiolitis. The main aims are: 1. To determine whether an optimal combination of NAVA support level and Positive End Expiratory Pressure (PEEP) exists that can: 1. maximise aspects of respiratory muscle unloading and 2. minimize air trapping 2. To evaluate the impact of two morphine infusion doses on comfort levels and respiratory drive (standard = 20mcg/kg/hr, low = 5mcg/kg/hr) during ventilation titration. Patients will act as their own control and will be randomly allocated to receive either standard or low dose morphine. They will receive the alternate dose on day 2. During each period of morphine dosing ventilation levels will be titrated and vital signs, respiratory parameters and comfort b scales will be recorded.