Responses, @Mobius:
First:
The 52-minute view adds little if anything clinically related that is not covered in, mainly, the 7-hour view or the 2 minute view posts. It is just a view above ground level that reveals interrelationships and some features l better than the view from 30,000 feet (7-hr). I like to see three levels and expect others may too.
Fortuitously blundering along, it occurs to me to check this out later, suspecting what I see is only an accident of local baseline errors noted just above. It's the visual "meshing" fit/match of the FR expiration curve profile with the upper profile of the biased TVd curve. It is pronounced in the graphic, particularly at largest FL, higher dC time and pressure rise. A rolling average TVc would likely wash out the prominence of baseline-exagerration TVd effects just as the latter washed out TVd from FL in box "h"--referring again to my 52-min view write up and later corrective note posted just above.
Second:
You asked, maybe challenged: Where I suggested how readers could check their inspiration work time. I believe I lost such comment as I may have drafted in a reply regarding the "dubious 45% between" median and 95% values. On the other hand, I may have backed off from doing so because skew between mean and mode can be large. I've applied the idea on occasion for my work. But here are other approaches as follow.
This very thread: Tue Nov 16, 2021 2:17 am:
https://www.cpaptalk.com/viewtopic/t183 ... l#p1399478
MY OPINION: I see one value of these nerdy TV-TVd-FL exercises, as above and explained (?) below, as helping me/us understand when there is need to look at lengthening Inspiratory times, unusually large and persistent I/E ratios, or better than I/E ratios, higher duty cycle ratios (Ti/(Ti+Te). Look at those indicators when sleep is unrestful with a low AHI. Look at them when the zoomed FL have high severity values or are of long duration;...
... lengthening inspiratory time relative to expiratory time indicates more work is being done to get needed TV and there can be some or all the more usual negative consequences of apnea, maybe worse because sleep medicine often overlooks insidious flow limitations.
Redmed devices show your whole night's I/E ratio 1/1.8 = 0.56, for example. Better than that, with OSCAR you can put the Inspiratory time curve above the Expiratory time curve and look at FL where curves diverge widest. Note the higher ratios, and how persistent they are and how they vary night to night. This is one of the ways to help decide if a certain food, Rx or activity is helping or hurting your sleep.
This thread: Sat Jan 08, 2022 5:31 am:
https://www.cpaptalk.com/viewtopic/t183 ... 0#p1402930
...(c) breathing work done as shown in the duty cycle ratio dC=Ti/(Ti+Te) and (d) all the other most relevant curves OSCAR presents showing Resmed sleep data from air flow.
The main takeaway--beyond whatever interrelationships the image may help one understand better--is highlighted as item "b" and explained some as matching item "B" in the text box below "b". Box "b" values are readouts from Insp. and Exp. Time curves where the green cursor intersects the two curves (Insp. curve above Exp. Curve) where the curves diverge and are most apart in the view. The same can be done by anyone having certain Resmed devices that report or make data available to OSCAR for showing inspiratory and expiratory times. The method can be used to assess sleep work done to fight flow limitation (whether flagged by FL or shown as any form of apnea or neither).
The single relevant research I've seen determined that normal sleepers, as tested, had a duty cycle ratio ("dC", I call them) of about 0.42 and sleepers with severe upper airway obstruction (UAO) had a ratio of about 0.53. As mentioned elsewhere, a Resmed patent application noted, however, that the ratio is about 0.3 for sleeping state and 0.4 for wake state.
See the graphic's curve illustration using I-E spread, cursor and box "b" as well as the annotation "B".
ELSEWHERE:
07-01-2021, 02:51 AM
Obviously I'm not a doctor, and have only guessed at what assessments I've made of what you present. In the image below I did the best I could with your small (lesss than photo sharp) image, rough tools and shaky hands to show you your Duty Cycle (= Time to inhale/(Time to inhale + Time to exhale) for one breath and its I/E equivalent look. DC, fairly new to me (except for old stick arc welders) is often used and is stated as a level, range or condition benchmark. In the ERS paper they show, for the small study, pre-dosing "normals" had DC, men and women, of 0.40, as I recall. But when they were dosed with air deprivation the severe FL level was 0.51.
11-12-2021, 04:04 AM
...[our] experts have shown us that one of the best ways to assess seriousness or extent of flow limitation (whether it is flagged or not), is to look at whether inspiration time is increased. As they know, better but slower measurements are the I/E and duty cycle (Ti/Ttotal ) ratios.
One way to spot high ratio periods is to put the Inspiratory time curve above the Expiration time curve and look at flow limited areas where the two curves diverge widely. It's not fool proof because the I-times can be shorter along with shorter E-times and have a high I/E or duty cycle ratio when the two curves are not widely divergent.
On the graphic I note that an increased duty cycle is preferable to an increased respiratory rate when dealing with flow limitation. That's as if we have a choice of which to use in sleep. Not so unless there is some kind of breathing training (Buteyko's methods?) that we could do to shift away from RR toward a duty cycle response.
12-12-2021, 03:04 AM
---1. RM users can see on their device screen Sleep Report their Ti and Ti/Te (or I/E average like 1:1.8 which equates to 1/1.8=0.56 or duty cycle=Ti/(Ti+Te)=1/(1+1.
= 0.36)
---2. Further, check significantly lengthier periods of wider divergence between the "Insp. Time" and "Exp.Time" curves OSCAR presents. First drag the Insp. Time curve next to and above the Exp. Time curve. At a wider-spread time spot that is of longer duration than most periods drag the cursor from spot to spot there and jot down some time reading pairs from the upper left corners of the two viewing windows where values show and do change as you move the cursor.
---3. Check a few ratios by dividing Ti by Te. Those ratios far larger than the I/E=0.56 shown above can (if they do not always) present a problem you may wish to review with your sleep doctor or . . . experts (among which I am not, though I might offer my thoughts while you await their attention).
01-26-2022, 02:02 PM
I looked at inspiration and expiration time (I and E times) in all your OSCAR summary tables and without exception they are inverted (I-time greater than E-time) at least in the Med and 95% columns, all columns I think. Further, I looked at this view attachment. . . just now, others variously and not focused as much. Disproportionately long I-times take sleep-work in themselves and do cause arousals fragmenting sleep.
Expanded RR Graph, which I think you requested:
- 15112728-RR.GIF (22.69 KiB) Viewed 7977 times
Ignore the emoji I could not eliminate, but tried. The item should show 1/(1+1.8 ) = 0.36