Post Reply 
Relationship between leaks and pressure?
Author Message
JJJ Offline

Advisory Members

Posts: 751
Joined: Apr 2012

Machine: ResMed S9 Autoset
Mask Type: Nasal mask
Mask Make & Model: Most recent: Wisp, Pilairo, Mirage Vista
Humidifier: ResMed S9 Autoset
CPAP Pressure: 17-20
CPAP Software: SleepyHead

Other Comments:

Sex: Male
Location: USA 97217

Post: #1
Relationship between leaks and pressure?
Because I am a very active sleeper I have struggled for a long time with unacceptable leak rates. Several months ago I started using a chin strap on top of the mask to help hold it in position.

I went through three different chin straps, the most recent being a custom make concoction. I am happy to say that this chin strap is finally doing the job. Here are data from the first five nights with it (the columns are average pressure, 95% pressure, maximum pressure, 95% leak rate, and maximum leak rate):

Mon 15.42 17.42 18.26 12.00 15.60
Tue 14.96 17.46 19.00 8.40 24.00
Wed 15.92 17.95 18.76 3.60 6.00
Thur 15.24 17.76 18.58 3.60 12.00
Fri 16.90 19.00 19.00 3.60 4.80

When looking at these data I am struck with how high my pressures have been since starting to use this chin strap. My machine is set for 14 to 19 cm. H2O and I have seen it get close to 19 once or twice in the past, but never hit it. It appears that I should probably increase the maximum all the way to 20.

Here are data for a week with the SP-CHADJ chin strap, which gave me pretty bad leak rates:

Mon 14.04 14.40 14.56 21.60 27.60
Tue 14.40 15.12 15.72 19.20 31.20
Wed 14.08 14.66 14.88 18.00 22.80
Thur 14.16 14.50 14.66 36.00 45.60
Fri 14.08 14.82 15.16 44.60 48.00

Note how my machine did not produce pressures nearly as high when the leak rates were higher. I looked at my daily data for the past couple of months and there is a loose but steady correlation between the leak rates and the pressures - the lower the leak rate the higher the pressure the machine will put out.

I find this very interesting.
09-21-2013 04:58 PM
Find all posts by this user Post Reply Quote this message in a reply

Donate to Apnea Board
PsychoMike Offline

Advisory Members

Posts: 551
Joined: Aug 2013

Machine: ResMed S9 AutoSet
Mask Type: Other
Mask Make & Model: Varies with mood, ResMed F10 is my primary
Humidifier: ResMed H5i
CPAP Pressure: 12-17
CPAP Software: SleepyHead

Other Comments: asthma, cyclist upgraditis, just a little crazy (honest :D )

Sex: Male
Location: Alberta, Canada

Post: #2
RE: Relationship between leaks and pressure?
It would be interesting to see if those are machine or mask pressures. Granted machine and mask pressures are related (in an ideal case, they should be equal, but there are losses pushing the air through the hose and with the venting at the mask). Regardless, though, it would make sense....bigger leaks mean more air escaping and a lower mask pressure...the air is escaping rather than being contained and generating pressure.
09-22-2013 12:18 AM
Find all posts by this user Post Reply Quote this message in a reply
Post Reply 


Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  Is it worth dropping pressure to get over leaks rich2905 19 1,274 11-16-2016 02:38 PM
Last Post: PaytonA
Question CA's, Mask type, and leaks/vent Rcgop 10 370 11-15-2016 03:02 PM
Last Post: robysue
  Which disturbs sleep most? High Pressure or Changing Pressure Rcgop 7 1,265 11-10-2016 07:37 PM
Last Post: Sleep2Snore
  Leaks (Too high?) sleepytimegal 9 440 11-06-2016 09:58 PM
Last Post: sleepytimegal
  Move alot and getting mask leaks HELP christinaleigh 10 522 11-06-2016 03:15 AM
Last Post: holden4th
  No apnea recorded during Large Leaks Roy289 12 518 10-05-2016 02:15 AM
Last Post: beet
Arrow Pressure vs. leaks dilemna Kakesim 7 532 09-20-2016 12:33 AM
Last Post: chill

Forum Jump:

Who's Online (Complete List)