For the more advanced Sleep Therapy patient, a BiLevel system makes breathing easier and more natural for adults who are having difficulty adjusting to continuous positive airway pressure therapy (CPAP). With a BiLevel system, the physician prescribes a specific Inspiratory Pressure (IPAP) and Expiratory Pressure (EPAP). This type of system mimics the natural breath more effectively and adds more comfort for the patient, increasing in compliance. These BiPAP machines also offer an optional humidification system for added comfort.