Breathing pattern identification, Flow limitations and posture

[SingleH]

Tryingtogetitright, thanks. I've had a lot of my own health problems, and aside from surgery most of those issues I've had to troubleshoot and resolve myself. I guess I have gotten plenty of practice and now applying it to my father. He's been lucky in having an enitre lifetime of good health and fitness with only his heart and now breathing being an issue in recent years.  He avoided doing any rehab or physio post surgery due to fear of covid and I believe it was that decision that also played a part in his breathing issues. Anyway his heart is now good, so its just the breathing issue that needs to be solved now.

[StuartC]

Just one last questions going back to your comment on iVAPS, apart from the volume assistance which may or may not be needed, am I right in thinking this would be the mode closest to "emulating" the experience of a Vauto machine, as iVAPS automatically adjusts pressure (+ volume) and you can set the min/max PS and Auto epap mode, which isnt available in any other mode.

Yes and no.

Yes, AutoEPAP is the same as Auto mode on an AirSense or VAuto mode on the VAuto machine.  However, when you enable AutoEPAP on the Lumis, it does not allow you to set a pressure support range less than 8, i.e. Ps max - Ps min >= 8.  Unfortunately you are not able to set PS min = PS max and make it operate as a VAuto.  

What I suggest you do when you get the machine is start out in ST mode.  iVAPS (without AutoEPAP) is simply ST mode with the added feature of variable PS to achieve a target volume.  So start "simple".  Unless SleepRoder or others have better suggestions:

• Set the EPAP that you need based on the current pressure and EPR setting.  13 seems fine for the pressure and did I see EPR of 2?  EPAP of 11 in that case.  Or 10 if EPR was set at 3 and you did not experience OAs then,
  
• Set IPAP to 4 above EPAP.  If EPR of 3 was not enough, you may was well start with PS = 4 and work up as necessary
  
• You have two choices for backup rate.  Either turn intelligent backup rate off and set the rate to 10.  Otherwise turn intelligent backup rate on and set target patient rate (TPR) to 12.  Then intelligent backup rate will allow RR to drop to 8 (2/3 of TPR) before intervening, but then it will drive the RR up to 12 and continue at that rate until spontaneous RR is detected at a rate higher than 12.  The important thing to know about intelligent backup rate is that it is used in iVAPS mode.  So if you intend switching to iVAPS, get used to it in ST mode first.
  
• Set Ti max to 2.5 seconds for RR of 12.  Otherwise maybe as long as 3 seconds?
  
• Set Ti min to 1 second, as SleepRider previously suggested
  
• SleepRider, what Rise Time should be set?  I have been told it needs to be short for obstructive conditions and may be longer otherwise.  However, I get the impression you are suggesting a rapid rise to apply IPAP as quickly as possible and hold it for the duration of Ti min.  If so, leave Rise Time at "Min"? 
  
• And also for Trigger and Cycle?  SleepRider, I get the impression that you would suggest a setting different to "Med", for Trigger at least.  Is that right?
  

By starting in ST mode, one of two things is likely.

1. You will work out settings that are effective without needing to use iVAPS.  That would be a great outcome.
   
2. You will work out settings and determine typical minute vent / tidal volume that are a good basis for setting initial iVAPS settings.  It is certainly better to do that than to switch to iVAPS without good ideas of settings.
   

[SingleH]

Hi Stuart,

Thanks for the explanation. Really useful info and sounds like a very logical plan which I will follow. I had only suggested the iVAPS mode as had seen that Resmed considers a scoliosis as a form of resitrictive lung disease/chest wall abnormality and suggest iVAPS for that. However he does not have a really extreme case of scolosis and has had a few capacity tests and they have been ok/average.

BTW is Ivaps considered a form of "ventilation" ie taking away the effort by the user. As I understand it the general concept is that you dont want to put someone on ventilation unless necessary as it removes the effort which in turn can lead to dependancy.

The unit should arrive in the next day or so, so will get it setup on ST mode.

[Jay51]

Great thread.  After reading through it I agree with both Sleeprider and StuartC.  Your father has a very complex and complicated medical history that almost requires breaking down all the problems into component parts and testing to see if that is what is causing the unusual wave form.  F & P machine won't work for him (like Sleeprider said) because it can't figure out what is going on and treat it successfully.  If an ENT has already looked at him, then not much else to do on this front.  With scoliosis and possible lung restriction, your always have IVAPS available later if you need it to boost his volume if it gets low in the future.  

Your question about the ventilator affecting his normal breathing:  I have used this ventilator about a year now every night all night.  I have not noticed any big, significant difference in my daily breathing (if anything, it is slightly better though).  My nightly breathing must be improving though.  Actually, if anything, it might actually be (ever so slowly) training me to make every single breath I take (whether asleep or awake) a bit deeper (which I consider good).  I think it might even be increasing my lung capacity ever so slightly (by stretching my lung tissue a little bit more with deeper breaths).  I do have more energy during the day from using it.  Only negative is some aerophagia that is tolerable for me.  

For me personally, I dropped to 79% on a home study on room air.  I think this was from getting stuck in a wicked positonal apnea cluster.  I finally got out of it and my SPO2 numbers went back to normal.  Very long CA's (or huge CA clusters) can drop SPO2 also, but most people don't have super long CA's (or huge CA clusters). Other people have the pattern of bouncing up and down back and forth all night with SPO2 though (and not bouncing too low though).  SPO2 is very important; and I believe like StuartC:  if the SPO2 is ok, then the setting don't have to be perfect (they can be a bit lower than normal - which is more tolerable in both our cases).  You can experiment with respiratory rate and tidal volume to get the best fit also.  Some people do better at a higher rate, some a lower rate, etc.  But like StuartC said also, it respiratory rate goes up, then tidal volume usually goes down; and vice versa.  I seem to be doing well at 500ml tidal volume and a normal to slightly lower than normal respiratory rate.  Your milage may vary. 

On the flip side, the same thing that happened to StuartC when he started IVAPS happened to me.  When we calculated everything for ml/kgIBW, etc. it was too difficult for me to sleep with (Pressure felt way too high).  It had to be set a little lower than normal for me to use it at night.  To me, 80% or so of the target is better than 0% because the 100% target cannot be tolerated.  My pulmonologist actually said that a ventilator set too high could actually cause injury to the lungs (but he said you would feel chest pain and it would force you to stop before you seriously injured yourself).  More caution is needed with patients that are less responsive though when using a ventilator.

Also, I use 2 eliminator (2.5" collars stacked on top of each other) every night.  It prevents chin tucking, keeps my mouth practically shut, and actually tilts my head back a little bit (like a CPR dummy).  I feel this opens my airway to the max (with the downside being some aerophagia).  If I am understanding your diagrams correctly, tilting the head back should be opening his airway more.  But you said it is hindering his breathing.  Try your pillow experiment because his neck position may be doing something to his soft tissue sleeping at that angle though.  Try your new pillow sleeping on his back and side to see any difference also.

[TryingToGetItRight]

You guys are amazing. I'm going to have to look into one of these cervical collars for myself as I have been trying to optimize my own breathing.

Back to the thread at hand, Jay51's advice that "the settings don't have to be perfect" as long as "SPO2 is ok" contradict my understanding that airway resistance can cause sleep disruptions even if SPO2 remain high. Maybe that's just myself projecting my own experience onto SingleH's father because I have a nasty case of UARS.

And also, fwiw, I would like to add that I've been using a ResMed S9 VPAP ventilation every night for the greater part of a decade and I would have no idea that it would affect how I breathe during the day.

[Jay51]

You are correct, TryingtoGetItRight.  "my understanding that airway resistance can cause sleep disruptions even if SPO2 remain high."  I was thinking big picture for SingleH's father - hypoxia and possible damage to body's vital organs from it.  Fine tuning and tweaking (optimzing therapy) to stop sleep disruptions (arousals, RERA's, flow limitations, etc.) can make for better sleep and feeling better and more energy and are well worth the effort IMO.  

[StuartC]

BTW is Ivaps considered a form of "ventilation" ie taking away the effort by the user. As I understand it the general concept is that you dont want to put someone on ventilation unless necessary as it removes the effort which in turn can lead to dependancy.

Two of the key pieces of information that I monitor from the machine are the "Spont. Trigger " and the "Spont. Cycle".  Unfortunately, they are only available from the Sleep Report on the machine, right near the very bottom of the list.  They do not get imported into OSACR, at least not that I have found.  Another "unfortunate" is that I set the Sleep Report to 1 Day, and that automatically gets reset to 1 Month any time power to the machine is disturbed.

"Spont." refers to the user spontaneously either triggering inspiration or cycling to expiration.  The opposite would be that the machine mandates trigger or cycle based on time settings, i.e. backup rate or Ti max.  So the higher the percentage shown, the more spontaneous breathing.  The lower the percentage shown, the more "ventilation" is occurring.

When I put myself into ST mode and tested the effect of changing a variety of settings, often the only objective change I saw was to the "Spont. Trigger" percentage.  I have no formal reason for doing this, I have not been told or read anything related, but I deliberately chose settings that resulted in the highest percentage of spontaneous trigger.  My logic was exactly as you suggest, I feel that it is better to breathe on your own.

Plus, of course, I really did not enjoy the experience of having spontaneous trigger percentages of 50 to 70%.  Almost certainly, what I was really feeling was the effect of the excessive tidal volumes that caused that to happen, rather than the action of mandatory triggering, but either way it was very unpleasant.

[SingleH]

Thanks Jay51,

Bit by bit I am working through each of the issues and trying to get a clearer picture. The content in this thread and forum in general has been very helpful as part of the process. I have a respiratory therapist who will take a look at his breathing and assess him from another perspective.

I now have the Lumis 150 VPA ST-A so I am going to start setting it up however I dont have a proper SP02 monitor (just the basic finger one) but something I will have to look at. For now I will have to get him setup with the new machine and then possibly see if I can add that element of monitoring later as he doesnt deal well with too many changes.

Regarding neck posture its just my theory that the backwards head posture is the problem based on what I have observed and the sounds he makes. Because he has a prounounced forward neck posture, combined with the rounded hump back from scoliosis, it kind of allows for his neck to be bent in the middle when he looks up or back Best way I can describe it is stick your head as far forward as you can from your shoulders and then while keeping that forward neck posture, look upwards. Almost every  single night after waking up his flow limitations are far worse than the first half of his sleep and the pressure always goes to max.

Just edited to add a couple of images I found. If you look at the 3rd image on the right this is his neck posture. If you then look at the Hyperextension image this is sometimes how he looks when he falls asleep in his chair and it is this position that he starts making the UARS like sounds from the previous video.Like he is breathing through a constricted airway. As he is doing this breathing you can see with each breath it gets louder and louder and the effort increases to breath and eventually he will wake up with a cough.  When I have visited them and stayed over in the past there have been a few occasions where I have heard the noise and seem him sleeping in a position with his head tilted back, even when he has pillows to support him. I think because he has such a forward head posture its easy for the head to tilt back into a bad angle because the neck isnt moving back with the head, its just the head angling back.

He needs to do something like chin tucks to improve it, but obviously its driven by a fundamental structural problem.

[attachment=54987]

[SingleH]

Two of the key pieces of information that I monitor from the machine are the "Spont. Trigger " and the "Spont. Cycle".  Unfortunately, they are only available from the Sleep Report on the machine, right near the very bottom of the list.  They do not get imported into OSACR, at least not that I have found.  Another "unfortunate" is that I set the Sleep Report to 1 Day, and that automatically gets reset to 1 Month any time power to the machine is disturbed.

Learning so much here! I will check those figures and check the Sleep report info.

Based on what you are outlining Trigger sensitivity would be set to high to allow for the user to initiate breathing rather than the machine?

Going back to your previous post with the suggested settings I came across some Resmed settings suggested for chest wall abnomalities. It suggested Trigger should be high and cycle should be low to create a longer inhalation time.

Im still learning all the terminology and functions, but is my understanding correct in that to try and normalise his wave forms the following settings would be applied for the following reasons:

High trigger sensitivity - to initiatiate the breath quickly.
Long Ti Min - to get a long inhalation and ignore the fake "mid inspiration expirations" that are observed as well as to make up for his inability to take long deep breaths.
Long Ti Max - To extend the overall breathing cycle
Low cycle - to avoid the machine detecting the drops below zero line as early breath termination

[Sleeprider]

The only issue I might change from the recommended chart for COPD is the rise time at 300 (milliseconds). This can be abrupt for most people and I suggest 0.5 in order to intercept the mid-inspiratory obstructions or fluctuations. Timing is going to take some experimentation and feedback from your dad. He does appear to have a short respiratory cycle and may feel as though the machine is driving his pace. Nonetheless, 0.8 TiMin seems to be an appropriate target, even for someone with a median time of inspiration slightly over one-second. There is really no way to know without trying the settings and getting feedback from your dad and the data. I suggest you start in S-mode rather than ST. Your dad has a lot of flow limitation, but not a lot of events, so he may not need a timed backup rate. If you're using ST mode, you will also need a backup rate (breaths per minute). We usually set that at 3-bpm less than normal median respiration and a common backup rate is 12 bpm. Your dad might be higher depending how he responds to the pressure support. Given his current apnea index is often less than 1-2 I would consider holding off pending a trial on VPAP-S.