(06-21-2015, 07:30 PM)nativedancer Wrote: recently, my dme exchanged a defective loaner for a brand new s9 vpap st. While using the loaner, my ahi had consistently been in the moderate 15-25 area. I have used the new machine for only 4 nights, but ahi's have not decreased to any great degree. Does a new machine take a while to adjust and begin giving accurate readings?
If your therapy pressures change, yes, I think it may take a few days for things to settle. But if only the machine is changed and same settings are being used, maybe not?
Can you post some data from ResScan statistics or from SleepyHead?
Are you using the machine in ST mode?
What are your settings for backup respiration rate (10?), Trigger (Medium?), Cycle (Medium?), Ti Min (0.3 second?), Ti Max (2 second?), Rise Time (300 millisecond)?
The default value for Ti Min (0.3 second) is often too low, with 0.6 or higher often being better. If the Flow waveform ever shows the IPAP pressure is lasting much shorter than the time you are actually inhaling, I would suggest increasing Ti Min. Sometimes our inhalation may start haltedly or slowly and the machine may end IPAP prematurely, when our inhalation is just beginning.
Copied from setup manual (and edited):
ST (Spontaneous/Timed) mode
The VPAP augments any breath initiated by the patient, but will also supply additional breaths should the patient breath rate fall below the set “backup” breath rate.
Triggering and cycling
Under normal conditions, the VPAP triggers (initiates IPAP) and cycles (terminates IPAP and changes to EPAP) as it senses the change in patient flow. In addition, the VPAP has adjustable trigger/cycle sensitivity to optimize the sensing level according to patient conditions.
Adjustable trigger sensitivity
"Very High" means triggers into IPAP earliest, as soon as we begin to inhale.
"Very Low" means triggers into IPAP too late.
Adjustable cycle sensitivity
"Very High" means cycles back into EPAP too early, as soon as the inhalation Flow barely starts to decrease.
"Very Low" means cycles back into EPAP latest, after inhalation is fully complete.
Rise time adjustment (Default is 300ms)
Rise time sets the time taken for the VPAP to reach IPAP, in milliseconds. The greater the rise time value, the longer it takes for pressure to increase from EPAP to IPAP.
TiControl™ – Inspiratory time control
Unique to ResMed CPAP and bilevel devices, TiControl allows you to set minimum and maximum limits on the time the device spends in IPAP, in seconds. The minimum and maximum time limits are set at either side of the patient’s ideal spontaneous inspiratory time, providing a ’controlled period’ for the patient to spontaneously cycle to EPAP.
The minimum time limit is set via the Ti Min parameter (default is 0.3s) and the maximum time limit is set via the Ti Max parameter (default is 2.0s).