Changes

Each mode has a differing way of calculating and delivering air.'''PTVVTV''' aims to hit a settable volume target, where pressure targets like IPAP and EPAP, whilst leaving volumes remains variable.'''VTVPTV''' aims to hit a settable volume targetpressure targets like IPAP and EPAP, where pressure remains the whilst leaving volumes variable.

Pressure targeted ventilation, which commonly use an external mask, naturally accounts for any leaks by simply ensuring that the pressure target is reached at all times. This can be done up until a the point where you hit the leak redline and , limiting the machine cannot machines ability to meet its pressure target. PTV is the mode we are largely dealing with here.

With pressure targeted ventilation, obviously the correct therapy pressures must be set, but this is only the first part of the puzzle. Volume, is an important variable we must control. This is determined by the interaction of complex machine settings, user physiology and pulmonary condition. The variability of this system necessitates careful assessment of each of these three areas, to allow making informed choices when trying to achieve '''ventilation synchrony''', . This is a concept whereby machine and user are in time and satisfying the respiratory need , without fighting each other, which . This can cause arousal and very poor sleep quality, despite possibly having great apnea and hypopnea control.

Due to the increasing complexity of Bi-level support, and the miriad of adjustments offered by Lowenstein, a number of predetermined settings called "scopes" are provided in each bi-level mode. These presets are designed and tested to be used as a starting point for differing pulmonary conditions and co-comorbidities.  These scopes are: