a reply to:
LordAhriman
Some surgeries last half a day or more, and are so tedious that there isn't a minute to spare, and the same mask and gloves are worn for 12+
hours.
Wrong.
They work in teams. A conjoined-twin operation can be broken down into many stages, like the initial incision, the work around the bones,
separation of the blood vessels, and reconstructive plastic surgery. A different team of surgeons scrubs into the operating room for each stage, most
of which take only a few hours to complete. That way, most of the surgeons don’t end up working for more than four or five hours in a
row.
Source
My understanding (I'm not a surgeon, but I do ask questions) is that there are usually stages during operations where the patient can be stabilized
enough to allow the surgeon to take a break. It simply isn't healthy to concentrate so hard for long at a time... not to mention it brings up the
possibility of making mistakes. I do know, from my experience as a research engineer, that continual concentration can be just as draining on the body
as physical labor, and moreso on one's mental acuity. Thus, I do not begrudge any surgeon working on me the opportunity to take a break along to
maintain mental acuity.
As for the CO2 level buildups... I find it absolutely amazing! It wasn't that long ago when talking about Global Warming that people were scared to
death that the air was so poisoned by CO2 levels of 0.04%. Now many of the same people are claiming that carbon dioxide isn't a big deal. Which is
it?
Carbon dioxide levels of 0.1% are safe; that's what one normally gets when one is sitting indoors in a building with good ventilation (greenhouses
also use levels up to 0.1% to enhance and accelerate plant growth). Levels of up to 0.2% can cause drowsiness; that's what one experiences when
sitting in a small conference room that isn't adequately ventilated. Up to 0.5% is considered mild hyercapnia and can cause several mildly
debilitating but also short-lived symptoms (headache, dizziness, mental confusion, etc.). Above that is considered a major health risk.
Now, the last time I looked, things like drowsiness, dizziness, and mental confusion were considered mental issues that indicated one was not mentally
performing at 100%. Perhaps that has changed; could someone clue me in if so?
Now, I don't know what the CO2 level beneath a mask is; I would assume it is below 0.1%. Understand, however, that exhaled breath contains about 4%
carbon dioxide as opposed to normal atmospheric levels of 0.04% (more during periods of physical exertion or strong mental concentration) and has an
O2 concentration of 16% as opposed to 21% in fresh air (less during periods of physical exertion or strong mental concentration). Most of that does
indeed filter through a properly worn mask,
but not all. It is physically impossible to create a filter that works without any pressure
differential, and that means it is physically impossible for a mask to allow for truly free breathing. Some amount of exhaled breath will remain in
the area behind the mask and be re-inhaled.
There is also the effect of a surgical mask becoming saturated with moisture with time. After all, that's its purpose: to trap moisture droplets.
Those do not magically disappear; they form a layer of moisture on the fabric of the mask. The amount of moisture will decrease the ability of the
mask to allow air exchange, as water surface tension will tend to block off the open portions of the weave. So after a certain amount of time, the
ability of the mask to allow for air exchange is decreased.
When asked, I advise people to simply remove the mask at every opportunity to allow their lungs to rest from the load and re-saturate their blood with
oxygen. My personal SWAG is that masks worn for a couple hours at a time during light exertion is not overly dangerous, but anything beyond that is
bringing up questions. Under heavy exertion (exercise or physical labor), I would be concerned about anything over 30 minutes. Of course, that will
vary due to the health of the individual; due to low blood flow, my personal limitation stands at around 2 minutes even at light exertion levels...
medical conditions are a thing.
I see no harm in posing the question of health effects due to increased CO2 levels, considering that we live in a society where many have somehow
decided that breathing in public is an assault and have therefore adopted face masks as a new standard. After all, I thought we were supposed to
"follow the science"; does that not include actually doing the science?
TheRedneck