asthmatics and nitrox

[Helen F H]

Im an asthmatic (certified to dive), and i have just got my advanced nitrox.  Someone said that using higher concentrations of oxygen can be detremental to asthmatics.  Anyone heard anything similar?  I know all the normal risks - burst lungs etc are much greater, but i have never heard of this.

[Jay]

I'm also an asthmatic (allergy caused) and have have had no problems diving with nitrox or using O2 as a deco gas. Asthma is normally triggered by dust or allergic agents (feathers / pollen etc) and so nitrox could be argued to be a safer fill as the gas is normally filtered at least twice. Pure O2 can agravate your lungs so maybe they could pose problems for asthmatics?

Anyone else?

[Phil Ennis]

<font color='#810541'>Have a dig on the DAN website, last time I looked there was a big section on Asthma but can't remember any connection to high ppo2's.

[Stu Sheridan]

<font color='#0000FF'>Hi Phil, i'm asthmatic too.
I've read all the usual stuff about why I shouldnt dive and promptly ignored it.

The thing you may be refering to is problems related to O2 and those with chronic lung disease.
Due to less o2 passing through the lung membrane into the blood, sufferers of CLD begin to &quot;evolve&quot; different respiratory controls.
Where normal folk will get the message from thier brain to breathe when CO2 hits set point, CLD sufferers breath when blood O2 falls beneath a certain point.
Hence, the high ppO2 in nitrox may over oxygenate the blood fooling their brain into a respiratory shutdown. ie, not feeling the need to breathe and being therfore suceptable to CO2 build up.

This is not the case in controlled/minor asthma. More relevant to emphysema and other conditions which effect the actual lung surface.

AFIK anyhoo. By the way m8, have just inducted one of your mates/trainees into our club. Dan Winstanley, seems a decent lad

Stu.

[Phil Ennis]

<font color='#810541'>Hi Stu, you must be in South Africa, or Dan didn't get far.

I haven't actually got asthma but interested in the subject amongst others. I think what you are on about is giving o2 on surface to someone suffering with the lung disfunction as anyone with this disorder would not pass a diver medical.

I did once get stuck in on this discussion but got told off by a Doctor for caliing it by the wrong name so I musn't do that again.

Give my regards to Dan and I hope he is getting plenty of diving done.

Take care.

[Stu Sheridan]

<font color='#0000FF'>That is what i'm on about m8, it has the same effect.
Stu