Too much oxygen?

[ERDoc]

There was this in Heart [1], but they excluded everything except 2 RCTs, one of which is the 1976 data people have mentioned [2]. The other was 50 patients, post streptokinase, who received either air via face mask or a nasal cannula at 4 LPM for 24 hours [3]. But the study was designed to investigate the occurence of hypoxemia and the ability of the physicians to recognise it clinically. So they didn't report much useful data.

[1]Wijesinghe M, Perrin K, Ranchord A, Simmonds M, Weatherall M, Beasley. Routine use of oxygen in the treatment of myocardial infarction: systematic review. Heart 2009;95:198–202. doi:10.1136/hrt.2008.148742

[2] Rawles JM, Kenmure AC. Controlled trial of oxygen in uncomplicated myocardial infarction. BMJ 1976;1:1121–3.

[3] Wilson AT, Channer KS. Hypoxaemia and supplemental oxygen therapy in the first 24 hours after myocardial infarction: the role of pulse oximetry. J R Coll Physicians Lond 1997;31:657–61

That might be the one I was thinking of. Maybe I read it in EM monthly.

[DwayneEMTP]

Didn't someone post an article here a few years back, I think it was called 'The Oxygen Paradox', in which they described some students looking at fresh hearts from cardiac arrests under slides? It seems like it talked about one of the students being reprimanded for creating slides from the wrong sample, as after a significant amount of time had passed there appeared to by no damage to the cells.

After a time they began to see this as a trend and would load the healthy cells from the donar heart and then wash them with blowby O2 and noticed significant cell death very quickly. Kinda sounds like something young Mr. Beiber might have posted back in the days when he was still bright eyed and enthusiastic....but not sure.

I think that they (I can't remember who 'they' were or if the article had any significant scientific value at all...just that it was really interesting reading.) attributed it to apoptosis...but again, I don't really remember. It's stuck in my head since, and I've looked for it a few times without success...

Dwayne

[Bieber]

http://www.sullydog.com/sullysites/qm/brainischemia101syllabus/index.htm

Great site, the information in it should be mandatory in every paramedic program...

Edited January 30, 2012 by Bieber

[Kiwiology]

Empirically let us consider the following

1) Hyperoxaemia (or at least supra physiologic amounts of oxygen) cause small arterioles and capillaries to constrict which will limit perfusion even more, not good in an ischaemic myocardium

2) If somebody has an ischaemic myocardium it is because there is a block in a coronary artery; the blood that's being blocked will still have a normal PaO2; the problem is a blockage and not hypoxaemia; additional oxygen will not do anything

It's also told that oxygen for a normooxaemic stroke patient is a bad thing; I have not studied the whys and hows of that one as much but I would imagine it's the same thing.

Is any other drug given out "just because"? IV fluid? glucose? adrenaline? ceftriaxone? midazolam?

Hell give me some of that midazolam just because now that I think of it!

[Bieber]

Not another drug, but another treatment we give out "just because" would be spinal immobilization.

[HellsBells]

http://www.bryanbledsoe.com/handouts

Third power point down.

[romneyfor2012]

I bet $1000 more patients have been hurt by lack of EMS oxygenation than too much EMS oxygenation.

[Vorenus]

I bet $1000 more patients have been hurt by lack of EMS oxygenation than too much EMS oxygenation.

I bet a thousand bucks more people have been hurt by knives than by spoons... so what?

Still sucks for the one`s that got the spoons, doesn`t it?

Sorry, but I can`t stand those kind of arguments, they are neither valuable for a discussion, nor do they have anything to do with Evidence Based Medicine.

[Kiwiology]

I bet $1000 more patients have been hurt by lack of EMS oxygenation than too much EMS oxygenation.

I too can't agree with such a statement; empirical evidence suggests far too much oxygen has been given for years; I've heard it from Paramedics in the UK, in the US, in Australia and even here.

Remember, ventilation is not oxygenation and ischaemia is not hypoxaemia.

I'll have my thousand dollars now.

[HellsBells]

bet $1000 more patients have been hurt by lack of EMS oxygenation than too much EMS oxygenation.

Care to expand on that? Or do you just enjoy making moronic statements?