Opinions vary as to when intervention is needed. Some respiratory therapists recommend beginning Bi-Pap therapy when vital capacity dips below 70%. Bi-PaP is non-invasive ventilatory assistance, which insures PALS are receiving sufficient air volume, and rests the lung muscles to provide comfort during sleeping and improve performance during the day. This can be achieved with a nasal mask or nasal pillows that are connected to a mechanical ventilator.