IPO/IPE considerations

[60plus]

How much do divers need to know about IPO and the factors that contribute to it. Why even at quite advanced recreational SCUBA is so little taught about WOB and the effects of F = ma (Newtons second law) on lung stress.

 

[Lorenzoid]

I had to think about the post title for a second before I understood. We Americans would refer to it as IPE, as we spell it "edema."

If you wish, we could edit the title to "IPO/IPE considerations" if you think it would get more attention.

 

[MB NZ]

I think divers should know that it exists, avoid physiological stress, avoid equipment with high work of breathing and wear appropriate exposure protection. Pretty generic diving advice. Above all, abort dive on developing any symptoms of respiratory distress. Hopefully, divers would not need to be told the latter!

 

[60plus]

Feel free to edit the title.
I raised this topic because a circular was sent round our club about IPO and although what it said was correct and a lot of significant information. Also a very experienced and competent instructor who assumed I would not know about IPO started giving me a bit of a lecture when he found out what sort of dives I was doing. Turned out I knew more about IPO than he did.
I am fortunate that my sister is a professor of medicine and former head of imaging sciences at a medical university so I have a very good source of info on physiology.

 

[Duke Dive Medicine]

How much do divers need to know about IPO and the factors that contribute to it. Why even at quite advanced recreational SCUBA is so little taught about WOB and the effects of F = ma (Newtons second law) on lung stress.

It would take an extremely high work of breathing (e.g. trying to pull air from a second stage under water after exhausting the gas supply) for that alone to produce pulmonary oedema in a diver, in which case it would be referred to as negative pressure pulmonary oedema. How high a work of breathing are you referring to? If you're thinking of that from a poorly adjusted regulator or high gas density at extreme depths, the diver would likely experience CO2 toxicity before IPO.

Best regards,
DDM

 

[dmaziuk]

Last I looked they weren't entirely clear on what causes IP[OE] in us couch potatoes, what are the physiological factors we need to be taught about other than "don't have high BP" (always a good advice) and "don't be a post-menopausal woman" (can't be helped)?

 

[Kendall Raine]

Last I looked they weren't entirely clear on what causes IP[OE] in us couch potatoes, what are the physiological factors we need to be taught about other than "don't have high BP" (always a good advice) and "don't be a post-menopausal woman" (can't be helped)?

Exactly. A friend's nephew died a few years ago from IPE. Mid-twenties. No comorbitities. Normal dive profile off Monterey (temperate). What could be learned/taught? Sh-t happens.

 

[clownfishsydney]

Article on my website about an incident I was involved in. At the bottom of that page there are links to some scientific papers on IPE.

Michael McFadyen's Scuba Diving Web Site

 

[Duke Dive Medicine]

Exactly. A friend's nephew died a few years ago from IPE. Mid-twenties. No comorbitities. Normal dive profile off Monterey (temperate). What could be learned/taught? Sh-t happens.

A lot has been learned about IPE. If your friend's nephew was young and healthy, unfortunately it's likely that he had a predisposition to it. There is a subset of the population in whom the pulmonary arteries do not dilate sufficiently in response to the influx of blood from immersion-related fluid shifts. This produces pulmonary hypertension which can lead to pulmonary edema. Cold water and increased work while in the water can exacerbate this.

In @dmaziuk 's couch potatoes, there is probably a cardiac component as well.

Best regards,
DDM

 

[Wibble]

Exactly. A friend's nephew died a few years ago from IPE. Mid-twenties. No comorbitities. Normal dive profile off Monterey (temperate). What could be learned/taught? Sh-t happens.

In "a Maltese diving incident" a party of 4 divers went out on a recreational dive and two died of IPO/E