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Hi All,
Re:
From: Ernest Christley <echristley@nc.rr.com>
Date: 2005/08/05 Fri PM 05:03:01 EDT
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Back from Osh/ Blood ox saturation
...
Could someone explain "exhaling under pressure"? How is this accomplished?
Most any asthmatic learns most of the process instinctively.
In "normal" breathing, the diaphram pulls downward, creating a low pressure zone around the lungs, which then fill from the higher ambient air pressure; exhalation is accomplished by simply relaxing and letting the air flow out. The problem is that this process doesn't completely fill or empty the lungs of air, and a lot of "stale" CO2-laden air remains.
The natural reaction to needing more oxygen is to pull more deeply on the diapram to suck in more air. What an asthmatic person discovers is that it is the exhalation part of the cycle that is "broken", so they learn to "push" on the diaphram to get more old air out, so that there will be more room for a fresh "charge" of air. What doesn't come so naturally is learning to pace both the inhalation and exhalation so that air spends enough time in the lungs for adequate O2/CO2 exchange. The pacing of the exhalation is accomplished by limiting the outflow of air to a lower rate than the diaphram could push it out. I do this by pursing my lips. In doing so, a higher-than-ambient pressure is creating inside the lungs, which seems to increase the efficiency of the O2/CO2 exchange.
Dale R.
COZY MkIV #1254
Ch's 4, 5, 9, 16, & 23 in-progress
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