04-10-2022, 11:29 PM
A question about calculation using OSCAR-reported "Med." values as variables
See http://www.apneaboard.com/forums/Thread-...#pid442145
Caution: Here is what may be wild speculation or confusion in a couple of areas.
This post is about interpreting and discerning differing flow limitation effects and about doing any "Med." value computation based on two or more OSCAR-reported statistical summary values. The intent is to get input on what I'll call a "fuzzy-'data'-analysis" problem. It is not to directly address and confuse member "temperance"'s therapy question with my speculations in his thread linked above. I will post reference to this post in his thread which raises a qood therapy question.
"temperance" reports low AHI with frequent awakenings and raises apt questions whether his leaks may explain his awakenings. As noted there, leaks alone could cause his awakenings. But IMO his inspiratory time is disproportionately long, causing extra work in breathing and may be adding to or causing his awakenings, if not more leaks.
I haven't replied to him, at least not yet, because I do not fully understand allowable uses of and interrelatedness among OSCAR summary statistics, say, a "Med." respiratory rate, a "Med." inspiratory time and a "Med." expiratory time as are in his OSCAR Summary report. Again, the the main question I raise is about calculations using fuzzy statistical values and it has come to mind many times. I have not seen it addressed anywhere, but I have wanted to do simple calculations using median values for one or more of respiratory rate, inspiration time or expiration time as below.
IMO, temperance could have a significant and nearly constant flow limitation from, say, hard-tissue upper airway obstruction (unnoted) together with irregularly spaced periods of low level, superimposed soft-tissue (floppy) flow limitation--the latter reflected in "FL" flags. Overall real flow limitation effects, flagged and unflagged, could be additive. Using Resmed's FL scaling for an unflagged hard-tissue flow limitation equivalent to FL= 0.50, for example, his unflagged "FL" would be 0.50. Adding to 0.50 his 99.5% FL up to 0.11, his total "FL" would be 0.61 or higher. Prolonged, that level or near it might be a critical level causing awakening, but that is not the issue here.
Further, hard tissue obstruction might cause some arousals alone and his added soft tissue flow limitation effect could add to it and be positional.
Illustration of calculation using temperance's median values:
IMO, the OSCAR reported median "Insp. Time" to median "Exp. Time" (I/E=1.94/1.8) ratio would be 1.08. His (inspiratory) duty cycle ratio would be 0.52. I/(I+E) = 1.94/(1.94+1.8) = 0.52. Those median values, from my computational point of view, are all fuzzy numbers, numbers that simply divide the upper half from the lower half of all numbers in size-sorted number lists. The meaning of ratios based on them is in question.
Both ratios are a bit high. One research report, using a different overall setup and equipment, reported a duty cycle of about 0.53 as indication of severe upper airway obstruction.
Here I plug his median Resp. Rate and Insp. Time into a respiratory rate (RR) formula and solve for "median" Exp. Time : median Resp. Rate = 15.80= 60 sec/(1.94 + Exp. Time). The result is "median" Exp. Time = 1.85 seconds. The OSCAR summary "Med. Exp. Time" is nearly equal at 1.80 seconds. This single case suggests calculation with medians may be OK on a limited basis.
Please, set me straight if you see this as nonsense.
Caution: Here is what may be wild speculation or confusion in a couple of areas.
This post is about interpreting and discerning differing flow limitation effects and about doing any "Med." value computation based on two or more OSCAR-reported statistical summary values. The intent is to get input on what I'll call a "fuzzy-'data'-analysis" problem. It is not to directly address and confuse member "temperance"'s therapy question with my speculations in his thread linked above. I will post reference to this post in his thread which raises a qood therapy question.
"temperance" reports low AHI with frequent awakenings and raises apt questions whether his leaks may explain his awakenings. As noted there, leaks alone could cause his awakenings. But IMO his inspiratory time is disproportionately long, causing extra work in breathing and may be adding to or causing his awakenings, if not more leaks.
I haven't replied to him, at least not yet, because I do not fully understand allowable uses of and interrelatedness among OSCAR summary statistics, say, a "Med." respiratory rate, a "Med." inspiratory time and a "Med." expiratory time as are in his OSCAR Summary report. Again, the the main question I raise is about calculations using fuzzy statistical values and it has come to mind many times. I have not seen it addressed anywhere, but I have wanted to do simple calculations using median values for one or more of respiratory rate, inspiration time or expiration time as below.
IMO, temperance could have a significant and nearly constant flow limitation from, say, hard-tissue upper airway obstruction (unnoted) together with irregularly spaced periods of low level, superimposed soft-tissue (floppy) flow limitation--the latter reflected in "FL" flags. Overall real flow limitation effects, flagged and unflagged, could be additive. Using Resmed's FL scaling for an unflagged hard-tissue flow limitation equivalent to FL= 0.50, for example, his unflagged "FL" would be 0.50. Adding to 0.50 his 99.5% FL up to 0.11, his total "FL" would be 0.61 or higher. Prolonged, that level or near it might be a critical level causing awakening, but that is not the issue here.
Further, hard tissue obstruction might cause some arousals alone and his added soft tissue flow limitation effect could add to it and be positional.
Illustration of calculation using temperance's median values:
IMO, the OSCAR reported median "Insp. Time" to median "Exp. Time" (I/E=1.94/1.8) ratio would be 1.08. His (inspiratory) duty cycle ratio would be 0.52. I/(I+E) = 1.94/(1.94+1.8) = 0.52. Those median values, from my computational point of view, are all fuzzy numbers, numbers that simply divide the upper half from the lower half of all numbers in size-sorted number lists. The meaning of ratios based on them is in question.
Both ratios are a bit high. One research report, using a different overall setup and equipment, reported a duty cycle of about 0.53 as indication of severe upper airway obstruction.
Here I plug his median Resp. Rate and Insp. Time into a respiratory rate (RR) formula and solve for "median" Exp. Time : median Resp. Rate = 15.80= 60 sec/(1.94 + Exp. Time). The result is "median" Exp. Time = 1.85 seconds. The OSCAR summary "Med. Exp. Time" is nearly equal at 1.80 seconds. This single case suggests calculation with medians may be OK on a limited basis.
Please, set me straight if you see this as nonsense.
I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.
Of my 3 once-needed, helpful, and adjunctive devices I have listed, only the accelerometer remains operative (but now idle). My second CMS50I died, too, of old age and the so-so Dreem 2 needs head-positioning band repair--if, indeed, Dreem even supports use of it now.
Of my 3 once-needed, helpful, and adjunctive devices I have listed, only the accelerometer remains operative (but now idle). My second CMS50I died, too, of old age and the so-so Dreem 2 needs head-positioning band repair--if, indeed, Dreem even supports use of it now.
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