With children because of the difficulty in assuring the patient's cooperation, the lack of available high quality masks and the resulting size of the air leak, synchrony between the ventilatory pattern of the patient and the support provided by the ventilator is poor. This problem had lead to repeated failure of noninvasive ventilation in children. The primary mode of noninvasive ventilatory support is pressure support (NIV PS). This mode is triggered to inspiration and cycled to exhalation by changes in patient inspiratory gas flow. But with air leaks the ability of the ventilator to coordinate with the patient is decreased.