Oxygen deficient atmospheres (Physiologists/Meds)???

[anonymous-user]

ThatPhilBrettGuy said:

Yes, linking to 28dayslater has unfortunate results. Best not to....

Whats 28dayslater then?

[RRS_Staffs]

Ive just Googled 28dayslater too - interesting site....

Ok back to topic

I have an interest in respiratory mechanics/physiology

I applaud the bravery of the OP in looking to put him/herself in severe risk environments and looking for casual back of fag packet type advice on an internet forum for protection!

This is the definitive text for a novice:
http://www.amazon.com/Respiratory-Physiology-Essen...

I cannot offer you any more advice other than to not put others in danger
That includes your mates but more importantly the rescue services

I cannot easily see how you can accurately predict or recognise cellular level hypoxia using some internet facts and a portable pulse oximeter - a superby useful instrument as well as misleading heap of junk in the wrong hands

Sorry

Edited by RRS_Staffs on Saturday 13th February 23:50

[ShadownINja]

RRS_Staffs said:

I cannot easily see how you can accurately predict or recognise cellular level hypoxia using some internet facts and a portable pulse oximeter - a superby useful instrument as well as misleading heap of junk in the wrong hands

Indeed, hence I stated earlier that different people respond in different ways. Research is still being done! http://www.xtreme-everest.co.uk/

[Tangent Police]

RRS_Staffs said:

I applaud the bravery of the OP in looking to put him/herself in severe risk environments and looking for casual back of fag packet type advice on an internet forum for protection!

This is on the back of hundreds of trips underground, talking with industry professionals, people who write risk assessments for such tasks, people with years of experience. Rescue teams, the works.

Bad air isn't half the danger. Getting buried probably is!

There is a lot of dogma around confined space atmospheres and looking for actual answers brings up the usual "If your flame goes out, or your meter alarms, get out"

I've learned some interesting stuff so far.

[Dr John]

It's very complex and not completely understood.

The important determinant of function is brain oxygen delivery (mass not pressure) and many factors affect this:
Inspired pO2 (what we're discussing here)
Oxygen consumption in the rest of the body - exercise, shivering, fever etc
Hb concentration (and type if considering the foetus)
Cardiac output
Atmospheric pressure (and the effect of the saturated vapour pressure of H2O which remains constant in the lungs)
Core Body Temperature
Blood and Tissue pH
2,3 DPG levels
paCO2
Respiratory rate
Lung capillary diffusion capacity (limited at altitude by pulmonary oedema)
V/Q matching (age, obesity, position)

There is a good overview of the physiology here:
http://bmb.oxfordjournals.org/cgi/reprint/55/1/96....

and an altitude calculator (which takes into account the effects of water SVP and respiratory alkalosis caused by hyperventilation) here:
http://www.altitude.org/calculators/oxygencalculat...

JF

[tangent police]

Update, I was good for +/-14% earlier. Got a bit of a headache at one point, breathing was pretty normal, heart rate was up by a fair bit. Exertion was like I had doubled in weight. Think I had mild tunnel vision as well. No emotional effects, no drunken giddyness. Pretty fine.

My mate had trouble ascending a shaft and complained of being breathless and knackered at 15%. I took it steady and was fine.

Edited by tangent police on Thursday 18th March 01:04