(10-20-2013 11:17 AM)Peter_C Wrote: Prior to last night, the 'trigger' and cycle' were on their default settings of 'MED'. I then changed them before going to sleep last night to 'LOW" (both of them).
Max IPAP: 25
Min EPAP: 7
Press SUP: 6
Ti Max: 4.0s
Ti Min: 0.3s
Leak Alert: OFF
Tube Length: 3m
Data from last night (10/19/2013)
Item | DAY | WEEK |
LEAK: 0.46L/s 0.48L/s
VT: 420-860 360-780
Resp Rate: 10-15 10-15
MV: 5.2-10.3 5.0-9.6
PRESS: 13.4 13.2
AHI: 19.6 11.2
AI: 4.4 2.3
%SPONT T: 0% 0%
%SPONT C: 0% 0%
I noticed no real change, other than having one of those nights where you don't even notice the air flow in your mask.
Your setting for Ti Max (4 seconds) is allowing maximum time for the machine to wait for you to end inhalation on your own, which should maximize % Spontaneous Cycle. Yet your machine reports % Spont C is zero.
The new setting for Cycle sensitivity (Low) would have made the machine less sensitive in detecting the end of inhalation, and would be expected to delay the start of EPAP and lower the % Spontaneous Cycle. But because your machine reported % Spont C was zero before the change, the change could not make it drop any lower.
The new setting for Trigger sensitivity (Low) would have made the machine less sensitive in detecting the start of inhalation, and would be expected to delay the start of IPAP and lower the % Spontaneous Trigger. But because your machine reported % Spont T was zero before the change, the change could not make it drop any lower.
But you also wrote:
I've played with my Ti MAX setting, and found that I am more comfortable at 4.0 than at a lower number (seems like I take long breaths). It's only been one night, but changing the TRIGGER and CYCLE from MED to LOW seemed to make everything 'smoother' (for lack of a better word)....
If your % Spont T and % Spont C were really, actually and truly zero both before and after the changes in Trigger sensitivity and Cycle sensitivity, then I think it would be impossible for these changes to have made any difference in how treatment behaved or felt.
The sensitivity settings only affect how the machine reacts when you initiate the transitions. If 0% of the transitions from EPAP to IPAP and back to EPAP were initiated "spontaneously" (by you), these sensitivity changes could have made no difference at all. That the changes in these settings make the treatment feel different than before makes me think the reported % Spont T and % Spont C of zero may be bogus, invalid and untrue.
Changing Trigger sensitivity to High or Very High would make the machine more sensitive in detecting the start of inhalation, and would be expected to speed up the start of IPAP and raise the % Spontaneous Trigger. It would also tend to increase Respiration Rate and tidal volume (Vt).
Likewise, changing Cycle sensitivity to High or Very High would make the machine more sensitive in detecting the end of inhalation, and would be expected to speed up the start of EPAP and raise the % Spontaneous Cycle. It would also tend to increase Respiration Rate.
By the way, if we are changing the Trigger and/or Cycle sensitivity to High or Very High (and especially if using a machine which does not distinguish and report Central Apneas versus Obstructive Apneas) we need to go slowly (making changes no more often than weekly) and we need to cautiously keep an eye on AHI, because for a few people (for a minority, I think) setting the Trigger and/or Cycle sensitivity to High or Very High may tend to increase their tendency to have central apneas.
Also, if you happen to be among those who are susceptible to having central apnea, your fairly high setting of 6 for Pressure Support may tend to increase the number of Central Apneas and/or episodes of Periodic Breathing (PB), which is when the depth/volume of breathing gradually increases (producing too much ventilation) followed by a slow decrease in depth of breathing until there is too little ventilation and the cycle repeats. In PB, the cycle of gradually increasing breathing followed by gradually decreasing breathing tends to repeat with a period of a minute or so.
At the extreme, Periodic Breathing turns into Cheyne-Stokes Respiration (CSR), in which central apneas replace the periods of shallow breathing. CSR, if lasting for long periods, can raise the CAI (average number of central apneas per hour) enough to warrant treatment with an ASV machine.
On the other hand, if the problem is very low Respiration Rate, then increasing the Pressure Support may be helpful to increase tidal volume and possibly Respiration Rate. (Just keep an eye on the
AHI in case higher PS or higher Trigger/Cycle sensitivity give rise to more central events.)
Increasing the PS tends to increase ventilation (increase "tidal" volume and Minute Ventilation) and tends to reduce obstructive events and Flow Limitation and can make sleep more restful, unless we are one of the people (a minority) who have a strong tendency toward central apnea.
Regarding Exhalation rate setting: This can be set to SLOW/MED/FAST.
Clinical Guide says to adjust this setting for patient comfort. SLOW causes a smoother but slower transition from IPAP to EPAP. FAST causes a faster but sharper transition from IPAP to EPAP. In those who are susceptible to central apnea, the FAST setting may increase the number of central events.