vpap auto 25 and PS setting

allend wrote:The DME's RT came by today and she thought the vpap auto 25 was in fact no good and she replaced it because even though I was set for 14/6 with a sleep study suggestion of 11/8 the machine was blowing at 14 / 6 right off the bat. The new one didn't. Then she said, let me see what the PS setting is. I assumed it was supposed to be 8 or (14-6). The RT said you don't need it that high if you are healthy and don't have stomach problems or lung problems. She said it would work fine with zero but she set it to 4. And that what was wrong with the machine. A PS of 8 automatically raised the Inhalation to 14 because 6 + 8 is 14. She said that on some machines you don't set the PS but you have to on the vpap auto 25.

allend wrote:I was set for 14/6 with a sleep study suggestion of 11/8

They are both good autobilevels, but you can't set either of them up correctly by attempting to use the numbers that were used on the other brand of machine. You have to think about the numbers and translate them for how you want the other brand of machine to run.

As an illustration, think of inhale and exhale as being two dancers. On the Respironics dance floor in the Respironics world, the two dancers dance two different dances without caring what the other dancer is doing. You simply set the size of the dance floor and you tell the dancers the maximum distance they are allowed to get from each other during their separate dances (there is an automatic minimum to keep them from bumping into each other), and they each do their own thing. Sometimes they dance close to each other, and sometimes they dance far apart. That distance varies. On the other hand, on a ResMed dance floor in the ResMed world, the two dancers do the same dance and are always the exact same distance from each other, but they can still roam the full dance floor, as long as they do it together. So if you mistakenly set the fixed distance of the dancers to be the same size as the dance floor, you keep the dancers from moving at all.

In other words, for the Respironics machine, you set the maximum IPAP and minimum EPAP (the size of the dance floor), then you set the MAXIMUM pressure support, or maximum distance allowed between the two separate pressures (dancers). For the ResMed, you similarly set a maximum and minimum (the dance floor), but then you set the ACTUAL pressure support, the fixed distance (or, difference) between inhale pressure and exhale pressure for the night. On that machine, those two pressures increase and decrease TOGETHER, NOT SEPARATELY, moment to moment, during the night (since the two do the same dance together).

It seems that the person who set up your machine didn't understand that difference between the two machines and set up the ResMed as if it were a Respironics. That is incorrect. If you want the ResMed to run as an auto, make sure the pressure support number is a number LESS THAN the distance between Max IPAP and Min EPAP so the dancers have some room to move. If the machine isn't set up correctly, it is the person who set it up who has kept the machine from running as an auto. That is not a limitation of the machine; it is a limitation of the person who set it up. That person was confused. So don't blame ResMed.

As for which approach to autobilevel dancing is best, I don't know. I just know the two approaches are different and that before you set up one brand after using another brand, you had better learn something about dance floors and choreography in the other world and translate from one to the other, if you want to see a dance.

jeff, who set up his own autobilevel, but is a lousy dancer in real life if he doesn't have a guitar in his hands.

allend wrote: . . . think there might be a little more fixed in that Maximum PS than you think. . . .

-SWS wrote:Unlike the Resmed case, Respironics will move EPAP and IPAP bound "in constant tandem" as an exception---not the rule (whether that's good or bad for any given patient). So with the Respironics machine if you need IPAP to move independently (e.g. to achieve more "ventilation" or WOB * reduction) then you set Max PS at or near the maximum value of 8 cm. If you want little or no variation between those two, then you set Max PS at or near the minimum value of 3 cm---or just run the machine as an ordinary BiLevel. All three BiLevel scenarios should serve a variety of underlying etiologies. If marginal albeit variable obesity-related hypoventilation is involved, for instance, then setting Max PS at 6 cm or 8 cm can theoretically help offload any variable effects of marginal obesity-related hypoventilation---via hypopnea response.

"Priority is given to the Max IPAP setting, followed by Min EPAP and then Pressure Support. The device automatically adjusts the lower-priority settings to ensure the device pressure limits are not exceeded.

"Example: Start with the settings Max IPAP = 15 cm H2O, Min EPAP = 10 cm H2O and Pressure Support = 3 cm H2O. If the Max IPAP setting is readjusted to 11 cm H2O, the device automatically reduces Pressure Support to 1 cm H2O. Max IPAP (the highest-priority setting) is preserved.

"Pressure Support: (VAuto mode) Pressure Support allows you to set the difference between inspiratory and expiratory pressure. This value can be adjusted for patient comfort. A maximum PS value of 10 cm H2O can be selected. In VAuto mode, if Pressure Support is above 6 cm H2O, treatment efficacy may be reduced."