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Sarah
01-23-2008, 03:20 PM
From the UCLA NewsRoom (http://www.newsroom.ucla.edu/portal/ucla/UCLA-Study-Reveals-Why-Bad-Things-7949.aspx)

UCLA Study Reveals Why Bad Things Happen Inside the Brain When We Inhale Pure Oxygen

By Elaine Schmidt | 5/21/2007 5:29:15 PM
It's a scenario straight out of "Grey's Anatomy"— a paramedic or doctor plops a mask over the face of a person struggling to breathe and begins dispensing pure oxygen.

Yet growing research suggests that inhaling straight oxygen can actually harm the brain. For the first time, a new UCLA brain-imaging study reveals why. Published in the May 22 edition of the journal Public Library of Science (PLoS) Medicine, the findings fly in the face of national guidelines for medical practice and recommend a new approach that adds carbon dioxide to the mix to preserve brain function in patients.

"For decades, the medical community has championed 100 percent oxygen as the gold standard for resuscitation. But no one has reported what happens inside our brains when we inhale pure oxygen," said Ronald Harper, distinguished professor of neurobiology at the David Geffen School of Medicine at UCLA. "What we discovered adds to a compelling body of evidence for modifying a widely practiced standard of care in the United States."

Harper's team used functional magnetic resonance imaging (fMRI) to capture detailed pictures of what occurs inside the human brain during two different breathing scenarios. The technique detects subtle increases in blood flow triggered by the activation of different parts of the brain, causing these regions to glow or light up on the color scan.

The researchers scanned the brains of 14 healthy children, ages 8 to 15, and monitored their breathing and heart rates as they inhaled 100 percent oxygen through a mouthpiece for two minutes. After waiting eight minutes for the youngsters' breathing to return to normal, the team added 5 percent carbon dioxide to the gas mixture and repeated the scan.

A comparison of the two scans revealed dramatic differences.


"When the children inhaled pure oxygen, their breathing quickened, resulting in the rapid exhalation of carbon dioxide from their bodies," said study co-author Paul Macey, a UCLA associate researcher in neurobiology. "The drop in carbon dioxide narrowed their blood vessels, preventing oxygen from reaching tissue in the brain and heart."

That's when something surprising happened on the MRI scan. Three brain structures suddenly lit up: the hippocampus, which helps control blood pressure; the cingulate cortex, which regulates pain perception and blood pressure; and the insula, which monitors physical and emotional stress.

All this activity awakened the hypothalamus, which regulates heart rate and hormonal outflow. Activation of the hypothalamus triggered a cascade of harmful reactions and released chemicals that can injure the brain and heart over time.

"Several brain areas responded to 100 percent oxygen by kicking the hypothalamus into overdrive," explained Harper. "The hypothalamus overreacted by dumping a massive flood of hormones and neurotransmitters into the bloodstream. These chemicals interfere with the heart's ability to pump blood and deliver oxygen — the opposite effect you want when you're trying to resuscitate someone."

When the children inhaled the carbon dioxide–oxygen mix, the hypothalamus' hyperactivity vanished from the MRI scan.

"Adding carbon dioxide to the oxygen relaxed the blood vessels, allowed oxygen to reach the heart and brain, calmed the hypothalamus and slowed the release of dangerous chemicals," Macey said.

"Pure oxygen kindles the match that fuels a forest fire of harm to the body," Harper said. "But a little whiff of carbon dioxide makes it all go away."

Based on their findings, the researchers strongly encourage health care providers to add carbon dioxide to oxygen dispensation, especially when resuscitating infants or administering oxygen for more than a few minutes. The new direction could hold particular implications for patients of stroke, heart attack, carbon monoxide poisoning and any long-term oxygen therapy.

"When in doubt about a case, the current medical approach is to increase oxygen levels and wait to see if the patient improves," explained Harper. "But no one has ever scanned patients' brains to examine how they respond to oxygen therapy."

Earlier data on high oxygen's harmful effects have already resulted in policy changes overseas. Instead of using straight oxygen, many European hospitals now resuscitate patients with room air, which contains a mixture of nitrogen, oxygen and carbon dioxide, or with a blend of oxygen and carbon dioxide.

Mary Woo, professor at the UCLA School of Nursing, was a co-author of the study, which was supported by the National Institute of Child Health and Development.

-UCLA-

scuba smurf
01-23-2008, 04:02 PM
very interesting, thank you for sharing.

smurf

Papa Bear
01-23-2008, 04:39 PM
They have also noticed changes in cells exposed to 100% O2 that is not healthy to the heart. Many years ago we had a near drowning on a beach dive. We pulled the diver from the surf and had him stabilized and breathing on the beach. The Life Guards arrived and administered 100% O2 and he freaked out and went nuts like a seizure! I always felt that they flushed out the CO2 in his system which took away his breathing reflex triggered by CO2. The idea the the brain triggers the sudden rush of adrenaline to help the body try to breath was always my theory! That was 1974! Glad to see we are always looking at the "Tried and true" methods, you never know what might really make a difference! We used to believe "Bleeding" was the best way to get the "Bad Blood" out! Never stop learning!

There was an article about death on a cellular level that basically stated that death is a slow process and that many cells in our bodies live for a long time in our bodies like hibernation. It spoke of O2 waking them up and them dying at a faster rate! If I find it again I will post a link!

hbh2oguard
01-24-2008, 01:50 AM
I knew that 100% O2 is bad for extended periods of time but after reading that I guess it's bad all together. It still feels great, ever if it's "bad" but there are always much worse things we can do for our body. Now I wonder how long it will take before CO2 is going to be mixed into medical O2 tanks.

seasnake
01-24-2008, 04:06 PM
Very interesting. What are the implications then where you would normally use 100% as a deco gas? (This is where somebody smart is supposed to chime in)

BamaCaveDiver
01-24-2008, 04:52 PM
Very interesting. What are the implications then where you would normally use 100% as a deco gas? (This is where somebody smart is supposed to chime in)

You are looking at a totally different scenario there snake, since your body is already pre-loaded with CO2, and you are still being subjected to increased presuure (a little still goes a long way thing.)

Papa Bear
01-24-2008, 05:28 PM
If we are talking ambient air then less than .005% CO2 in the human exhale we are looking at 1.9% plus our minus depending on load! Not MUCH!

hbh2oguard
01-24-2008, 05:51 PM
I was thinking about it, and for the medical there is a very simple fix. Stop using non-rebreater masks (the kind with the resivor bag) and start using rebreater masks which give the patient about 95%O2 instead of the 99-100% with the non-rebreater masks.

Papa Bear
01-24-2008, 06:19 PM
I just re-certified my O2 Administrator and we were taught to use re-breather mask from the start! This might be the new thinking!

hbh2oguard
01-24-2008, 09:35 PM
Well I guess that's good to hear, I just went through an EMT recert and all that most medical agencies (medics, lifeguards, even police who were in the class) used were either non-rebreater or on very rare occasions nasal canuals. I know that's all we carry on our trucks where I work, but maybe with time rebreaters will become move avaible.

nat
01-25-2008, 03:52 PM
As a Midwife, this thread is very interesting from my point of view within a clinical setting. We routinely respond to compromised patients by, amongst other interventions, providing 100% O2 for up to and beyond 4 hrs.

This is often initiated by the Midwife whilst awaiting medical personnel to attend in the case of an emergency. Although it's not often realistically carried out, O2 is classed as a drug and should be prescribed by a Doctor.

I wonder what implications this will have in clinical practice as well as the impact these findings will have outside of a hospital... I'll have to keep my ear to the ground on this subject!

Papa Bear
01-25-2008, 09:46 PM
We are only talking about near drownings here and I haven't seen other studies other that those about Ant-Occidents and the fact that O2 is a poisons by product of all that is green! I think in the scope of this conversation it is about the reflective actions the body goes through when drowning! For other cases it is about keeping the brain cells flooded with O2 so that it enriches the blood that is MOVING through the system loaded with O2. I can't see a reason not to continue that practice. Having said that the above mentioned study did look at Heart attack victims in the ER, but again their hearts had stopped! It will take years of studies to change existing procedures!

seasnake
01-26-2008, 02:00 AM
We are only talking about near drownings? I took it from the study they were talking about any use of 100% O2.

Papa Bear
01-26-2008, 02:26 AM
No, just where the heart and respiration have ceased and the person is revived. It was first notice in Cold Water near drownings where people have been brought back after hours in cold water.

hbh2oguard
01-26-2008, 03:12 AM
huh?:confused: The study was with young kids and their body functions when on different amounts of O2, or atleast how I read it. What's this about near drownings???

Papa Bear
01-26-2008, 04:46 AM
I was referring to the one I mentioned about adverse effects on Heart Attack Victims! I may have drifted of the original study a bit? But I was referring the one that would most impact us as divers and potential near drowning victims, since its been a long time since I have been a kid! Sorry for any misunderstand!

Papa Bear
01-26-2008, 04:47 AM
I will look for more but here is some good stuff:
http://lib.bioinfo.pl/meid:53985

Papa Bear
01-26-2008, 05:34 AM
Here is another I found: http://www.damninteresting.com/?p=860
Also for our midwife I found a couple interesting articles about using room air at birth rather the O2. Easy search on Google!

Papa Bear
01-26-2008, 05:49 AM
one more, but I knew I would find it! You have to love the internet!
http://www.sciam.com/article.cfm? (http://www.sciam.com/article.cfm?chanID=sa003&articleID=B65F1583-E7F2-99DF-350637B37CE5CA44&ref=rss)chanID=sa003&articleID=B65F1583-E7F2-99DF-350637B37CE5CA44&ref=rss

hbh2oguard
01-26-2008, 04:21 PM
thanks for clearing it up, great sites!

nat
01-26-2008, 05:15 PM
Thanks Papa Bear...

I guess I was just thinking how the study could have the potential to spark research into critical care in general. I did take a quick look at what evidence is available on the research databases for my particular aspect of healthcare. We have been aware of the potential danger to infants (resuscitation and long-term use, wise) for some time but nothing for adults that I can see so far :( .

Very interesting articles - Any additonal knowledge to advance resuscitation techniques, for whatever population of people is a great thing and it's great that you made me aware of it. Thanks :)

scuba smurf
01-26-2008, 08:04 PM
We are only talking about near drownings? I took it from the study they were talking about any use of 100% O2.

I agree snake, I just reread it again, I must be missing it in there somewhere but I can't find anything that mentions near drownings

scuba smurf
01-26-2008, 08:05 PM
thanks for the info papa bear:) interesting reads

BillGraham
01-27-2008, 03:41 PM
In terms of therapeutic value, I was somewhat overserved when I went to a concert on Friday night, and I grabbed one of my 0-2 bottles out in the garage yesterday and stuck a regulator in my mouth. It seemed to kill the hangover a bit :cool:

nat
01-27-2008, 05:29 PM
Haha, I have to agree with you there...and it saves more time than getting a pal to rig up a litre of saline infusion. 100% O2 is also great for getting rid of bruises if applied directly over the offending site (Overservice at the bar can increase the chances of waking up with random mysterious bruises...or so I've heard) ;)

tomckernon
09-04-2008, 12:54 PM
That's interesting. It has also been noted in studies that injecting HGH prior to the use of 100% O2 breathing allows the patient to breath the O2 better and longer w/o other complications.

For Premature babies, a liquid ventilator using a Oxygenated Perflourocarbon emulsion mixture is used. The mixture boosts O2 40% above that in air, or about 30%.