One thing I forgot to add in that post was information about the RAMP feature on both machines. And alas, I can't seem to go back and edit the original post. So here's an addition to my long post comparing the Resmed S9 AutoSet and PR System One Auto CPAP:
Comparison of the RAMP feature on the Resmed S9 AutoSet and the PR System One Auto CPAP
On both machines, the RAMP feature is disabled if the minimum pressure setting is set to 4 cm since the minimum starting ramp pressure is 4cm. On both systems the RAMP feature allows the user to start the session at a pressure below
the minimum pressure setting. The pressure will slowly ramp up (in a linear fashion) to the minimum pressure setting over a fixed amount of time that can be controlled through the settings.
Many DMEs will typically use 4 or 5 cm as the default starting ramp pressure and 30 or 40 minutes as the default ramp time. For many newbies, this does provide some real measure of comfort if they feel overwhelmed by the airflow at their prescribed pressure settings. But many other people have real trouble breathing at 4 or 5 cm of pressure because at this low of pressure there is a sensation that there's not that much air coming through the mask. (In reality, there's still plenty of air being blown through the system even at 4 or 5 cm.) As a consequence many people find the ramp a double-edged sword. It may help during the first few weeks or months, but it may make things more difficult because the feeling of "not enough air coming in through the mask" can lead to a sense of panic.
The RAMP on the Resmed S9 machine
The starting ramp pressure
must be set from inside the clinical menu. It can be set from 4cm to anything less than the patient's minimum pressure setting. The ramp time
can be set from the patient's set up menu and it can be set in 5-minute increments from anywhere between 5 minutes and 45 minutes. The longer the ramp time, the gentler the increase in pressure will be. The smaller the gap between the starting ramp pressure and the minimum pressure setting, the gentler the increase in pressure will be.
Any time the S9 is turned off and then back ON during the night, the machine will start at the beginning of a full ramp period and there is no way to easily disable this in use. In other words, it is impossible to use a 45 minute ramp at the beginning of the night and then allow yourself to turn the machine off and back on for a bathroom break in the middle of the night. without restarting the ramp.
During the ramp up period, the S9 will NOT record flag any events and it will NOT respond to any events. If you fall asleep well before the end of your ramp period and start having apneas or hypopneas because the pressure is still far below your therapeutic pressure, these "ramp period" apneas will NOT show up in the data---regardless of whether you look at the data on the LCD, in ResScan, or in SleepyHead.
Because the ramp cannot be temporarily disabled and because the S9 does not flag or respond to events that occur during the ramp period, it is critical that S9 users who chose (or need) to use the RAMP feature be conscious of the following things when setting up their ramp settings:
The RAMP on the PR System One Auto CPAP machine
- The ramp time should be set to approximate the user's most typical latency to sleep. If the ramp period is set much longer than the typical latency to sleep, the user may have long periods of sleep where the machine provides inadequate protection AND the events during these ramp up periods will NOT be flagged.
- The starting ramp pressure should be set as close to the user's minimum pressure setting as possible for comfort. (And the minimum pressure setting should not be too far below the user's titrated pressure needs.) This will insure that during the time the patient is sleeping during the ramp period, the pressure will at least be something closer to therapeutic, and hence of some therapeutic use in preventing at least some of the user's typical OSA events
The starting ramp time
must be set from inside the clinical menu. It can be set in 5-minute increments from anywhere between 5 minutes and 45 minutes. The ramp pressure
can be set from the patient's set up menu and it can be set anywhere between 4cm and the patient's minimum pressure setting. The longer the ramp time, the gentler the increase in pressure will be. The smaller the gap between the starting ramp pressure and the minimum pressure setting, the gentler the increase in pressure will be.
In order to use the ramp, the patient must both turn the machine ON and press the RAMP button, which is a small button with a triangular icon on it. The RAMP button may be pressed at any point when the machine is ON during the night. When the RAMP button is pressed, the machine will lower the pressure to the starting RAMP pressure and will increase the pressure back up to the minimum pressure setting over the RAMP time period. If the patient turns the machine off during the night and then back on without
pressing the RAMP button, the machine will start with the pressure set to the minimum
pressure rather than the starting ramp pressure.
The System One will record and respond to obstructive apneas, hypopneas, snores, RERAs, and flow increases during the RAMP period with an appropriate increase in pressure as dictated by the System One's Auto Algorithm. For example, if the machine detects two or more apneas in close proximity, the machine will increase the pressure by 1cm and continue the ramping up of the pressure to the minumum pressure setting from there. The events detected during the RAMP period will show up in the data when you look at it in Encore and SleepyHead. (They'll also be part of the averages on the machine's LCD averages.)
Overall, the Ramp is a bit more flexible on the System One. But even so, it is important for a new user to still be aware that continually hitting the Ramp button to lower the pressure below the minimum pressure setting may not be a good idea----particularly if the ramp time is extremely long and if the starting ramp pressure is much lower than the minimum pressure setting.