Bilevel Terminology

• IPAP (inspiratory positive airway pressure) - The pressure delivered to assist the patient when inhaling
• EPAP (expiratory positive airway pressure) - The pressure delivered when the patient is exhaling. Naturally this pressure is less than IPAP because the patient breathes against it. For many conditions EPAP is necessary for airway patency
• Maximum IPAP time (maximum time a device will deliver IPAP) - Most bilevel devices have a three-second, non-adjustable maximum IPAP time. ResMed bilevel devices are the only ones with the IPAP MaxTM feature that allows clinicians to set the optimal maximum IPAP time for each patient during spontaneous breathing mode. Recent studies show that almost all patients on bilevel therapy experience mouth leaks, which interfere with a device's triggering sensitivity from IPAP to EPAP. Poor triggering sensitivity results in poor synchrony of the patient's spontaneous breathing pattern and the bilevel's assistance. Asynchrony causes the patient to exhale against a higher pressure, increasing work of breathing and reducing the comfort and quality of therapy
• IPAP Max counteracts the effect of mouth leak and improves synchrony so that therapy remains comfortable even in the presence of mouth leaks

1. Most bilevel devices have a three-second, non-adjustable maximum IPAP time