Post Reply 
Operating Altitude Question
Author Message
genes Offline

Preferred Members-2

Posts: 59
Joined: Sep 2012

Machine: Respronics Auto Cpap
Mask Type: Nasal mask
Mask Make & Model:
Humidifier: Respronics
CPAP Pressure: 17 -20
CPAP Software: EncorePro

Other Comments:

Sex: Male

Post: #21
RE: Operating Altitude Question
The following link about fans might help explain some of what happens at with a cpap at different altitudes. It supports what some of the posts are saying. Changing altitude with your cpap may not cause apneas but it could decrease the amount of oxygen you breath.

It says that a fan is a constant volume machine so for a given cpap (gage) pressure the machine should pump the same volume flow rate at all altitudes. The formulas say that the mass flow rate is proportional to the density so as the altitude increases the absolute pressure and mass flow rate will decrease. Someone said that the percent of oxygen in the air is the same at any altitude which makes sense but there will be less oxygen in the air at higher elevations because the air is less dense so there will be less air and oxygen per liter of air that you breath. If you increase the cpap pressure at higher altitudes the absolute pressure of the cpap air will increase so you will get more oxygen. I did not figure out how much the cpap pressure needs to be increased to compensate for altitude but they did in one of the posts I think.

I haven't tried to figure the whole altitude thing out yet but hopefully this link will help. The post may be confusing so look at the link.

12-25-2012 11:47 PM
Find all posts by this user Post Reply Quote this message in a reply

Donate to Apnea Board
Post Reply 

Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  High Altitude experience with Dreamstation APAP. NorthernGuy 6 513 08-31-2016 08:52 PM
Last Post: NorthernGuy
  1) AHI by altitude? 2) Elevated AHI but decent SpO2 glaxelson 5 594 03-09-2016 12:06 PM
Last Post: PaytonA
  Altitude dzwiss 8 672 02-28-2016 05:03 PM
Last Post: dzwiss
  Anecdotal experience regarding CPAP and altitude wolson 5 735 02-27-2016 03:42 PM
Last Post: SideSleeper
  [CPAP] Altitude Lyndaloofa 5 763 09-28-2015 02:35 PM
Last Post: surferdude2
  Change in altitude - AHI went up Rastur 5 1,233 09-20-2015 04:46 PM
Last Post: vsheline
  New to CPAP/BiPAP - living at High Altitude forJO 5 1,584 08-15-2015 03:25 PM
Last Post: vsheline

Forum Jump:

Who's Online (Complete List)