UKC

I've been reading about the strange effects of COVID 19 on some patients, particularly low blood oxygen levels, similar to being at altitude, with the patient not being aware of their oxygen deficiency.

I'm guessing that there are quite a few people on UKC with technical knowledge of hypoxia, and wondered if anyone can add to the limited information appearing in the press?

https://www.liebertpub.com/doi/pdfplus/10.1089/ham.2020.0055
 

On this topic this article is worth a read:

https://www.nytimes.com/2020/04/20/opinion/coronavirus-testing-pneumonia.ht...

Thanks for this- this is exactly the sort of answer I was hoping for when I posted (with some trepidation).

Thanks, I had read this article, and it was one of the things that made me want to find out more. I'm not hearing many people comparing it to flu at present.

Haven't looked at UKC for a day, and the first thing I click on, someone's asking an interesting technical question, and it gets two Dislikes. This website really is for sickos. I'm pissing off again having stayed for just 50 seconds. There are much more interesting things to do.

This was discussed last week. Hope it helps

https://www.ukclimbing.com/forums/off_belay/pulse_oximeters-718557

Just switch off the like/dislike feature and the site goes back to the way you used to remember it.

People either reply to you or they don't. You also have the added bonus of not trying to interpret why or how people use those stupid buttons.

You're reading way *way* too much into it.  You should take Lemming's advice and just turn the feature off if it bothers you that much.

Missed this one, and have just had a read through. One thing which I wasn't clear about, and hopefully you can clear up, is that you say that low oxygen levels will mean faster breathing i.e the obvious bodily response. The thing that sounded strange to me though was people having very low oxygen levels but no other outward signs  (if I've understood this correctly).

It would be interesting if the weekly stats page for most frequent posters also had the data for most frequent likers and dislikers.   There may be a small number of 'dislike stalkers' giving out a vastly disproportionate number of dislikes.  

Way above my pay grade. That's doctor stuff.

All I know is that some people who have chronic breathing problems over many, many years learn to live with higher levels of carbon dioxide in their blood stream than oxygen. Very complex stuff.

Basically a ventilation / perfusion mismatch . Oxygen is being delivered to areas of lung which can’t absorb it normally due to the disease affecting the tiny blood vessels and their branches in the lung. 
 Unlike other respiratory distress syndromes , many ( not all ) Covid patients have normal lung compliance which means it does not take a lot of energy to expand it ( think normal ballon as opposed to a really stiff one ) . They breath deeper and also faster to help compensate. This interestingly seems to cause patient induced lung damaged ( think of damaging that balloon by over blowing it , when the balloon is already slightly damaged) . 

 

Happy hypoxia. Outlined in this article.

https://emcrit.org/pulmcrit/happy-hypoxemia-physiology/?fbclid=IwAR1gQ1rBPU...

I agree, it's really annoying, Gordon. The OP asked an interesting and useful question, and moreover asked it carefully and well. So like you I don't get the 2 dislikes. Best to ignore them IMO, just IMO

I’ll add a foot note : 

The V/Q ( air / blood) mismatch in the lung causes low oxygen saturation . You breath faster / more deeply . This removes CO2 from the blood in the lung because it is highly soluble  and has a linear dissociation curve relative to oxygen which flattens off , so breath more , loose CO2 ( to low levels) but don’t much increase your oxygen saturation. CO2 is responsible for some ‘ drive’ to increase breathing but Covid patients typically have low levels. 
Some fluid gets into spaces between the air sacks in the lung giving the now well known appearance on X ray and making gas exchange harder . However, it’s probably the micro blood vessels in the lung malfunctioning which causes the V/Q mismatch and the initial hypoxia rather than areas of collapsed lung. 
 Everything points to this being a body wide thing , effecting many bits such as kidneys, other blood vessels etc. 
Pretty interesting. 

But it's just so unattractive. What's the point of visiting an unattractive website that attracts unattractive visitors? I just don't get it. Even if you can turn those buttons off it doesn't mean those lurking weirdos have gone away. I'd much rather give it a miss. It's a bit like eating food that's past its sell-by date. I can't see the attraction.

I know, Gordon, it's hard to get away from. But (puts gloomy hat on) sadly and unavoidably, the truth is that we might meet unattractive people anywhere, at work, at the crag, in supermarkets, in pubs, in the Vatican, in Parliament. That doesn't mean we shouldn't go to those places. What I do for dislikers (I get them automatically whatever I post - if someone asked "What day is it?" and I replied "Monday", I'd get a dislike) is [a] tune them out [b] remember that the vast majority of people on UKC are not at all like that [c] feel a bit sorry for them and move on

I suppose what happened was I just saw one of two bad-tempered threads here over the last few days, and it put me in a bad mood. Yup, of course the vast majority of people here, as everywhere, are OK, and more than OK.

Happy hypoxia in the national press...

https://www.theguardian.com/world/2020/may/03/happy-hypoxia-unusual-coronav...

I have a Samsung phone that has an app. ( Samsung health) that can measure blood oxygen levels and pulse, ...  both are measured simultaneously with the “stress” button. 
 

This was one of the articles that prompted me to ask for more information. It does sound like the stuff of a Michael Crichton novel- very strange and concerning, and as yet we have no idea of the long term health consequences for survivors.

Ok, here goes (based on my own physiology knowledge and that of my wife who teaches physiology for paramedics):

Normally the increased breathing reflex is triggered by cells measuring CO2 levels in the blood. If this consistently leads to too low O2 levels the body can "learn" to trigger the same response in response to O2 levels, which are continuously measured by the body anyway but not normally used as a parameter in the physiological feedback loop that controls breathing.

The most common example for this is COPD patients, where physiologically roughly the same thing happens as in the "happy hypoxia" patients, i.e. sufficient lung perfusion for CO2 clearance bt not blood oxygenation, but of course much more gradually.

Since this reorganization of the control loop takes months, it is of no use to acute CV patients, who therefore continue to adjust their breathing according to CO2 levels and therefore become hypoxic.

CB

I didn't realise that was possible! Thanks, I've just turned it off.

Which is why you never hyperventilate before free diving - it can lower the blood CO2 level more than it raises blood O2, meaning you run out of sufficient O2 without ever having an urge to breath warning you.

Pretty sure several disaster movies got that one wrong...

Rather off topic, but I was doing a PhD on this stuff a decade ago, one thing to keep in mind is that that type of pulse oximetry is not especially accurate, *especially* mobile phone stuff. Even the typical pulse oximeters clinicians use are mainly great for measuring trends rather than absolute values, especially as in lower SpO2 values. Of course, that is absolutely fine most of the time, if you are seeing a patient's SpO2 drop you don't care whether 70% is 70%, 68% or 72%. We were working on accurate tissue oximetry using hyperspectral cameras trying to account for the actually rather bad effects of light scattering in tissue, something that very much invalidates Lambert-Beer Law in that medium.  Never finished that PhD and haven't caught up with what the group is doing these days, so unfortunately I don't know where that work ended up.