AVOID is in

[triemal04]

http://www.cardiosource.org/science-and-quality/clinical-trials/a/avoid.aspx?WT.mc_id=Twitter

http://www.cardiosource.org/~/media...ls/AHA14/AVOID Presentation Slides AHA14.ashx

In a nutshell, patients in the O2 arm had a larger infarct with more adverse events both while in the hospital, and after discharge (including another MI).

But, the patients in the non-O2 arm had a higher mortality rate at discharge and 6 months, and appears a higher rate of cardiogenic shock

This only included patients who were not hypoxic, which is good, but the authors choose to use an admitted non-standard therapy (8lpm by facemask) instead of the standard 2-4lpm by cannula, which is bad.

Discuss.

 

[Ewok Jerky]

Meh. The only statistically significant finding was recurrent in-hospital MI, and whatever "infarct size on cardiac enzymes" is.

No difference in mortality or recurrent MI at 6 months.

It's interesting that the oxygen group had higher rates of HTN and dislipidemia, and were also more likely to be put on clopidagril. Maybe the oxygen group was a higher risk population?

Not that I think we should be gassing everyone who walks in the door, I'm just not too impressed with this study.

Also 8L/m is ridiculous.

 

[Smash]

Given that this was a true randomized trial it would be remarkable to randomize a higher risk population to one arm of it. I imagine that having another MI, be it in hospital or later, would be an important patient oriented outcome. I know it would be for me!
What is ridiculous about 8l/min of O2?

 

[Ewok Jerky]

Just because a study is randomized does not automatically translate to well balanced groups.The method of randomization was not explicit, and it certainly wasn't blinded at all.

The O2 group had higher rates of HTN and dyslipiddmia, 2 known risk factors for heart disease.

I can certainly see a scenario where a patient presents with probable MI based on Hx and exam. A biased researcher, who believes O2 can help, "randomized" this one to the oxygen arm hoping to improve this patients outcome. Thus, higher risk patients end up in the O2 group and it would not be surpirising if that group ended up with worse outcomes, such as second MI.

Ok maybe "ridiculous" was a strong word, maybe "not realistic" would be a better choice. I don't know anyone who gives 8L/m to a patient who is not in respiratory distress.

 

[Handsome Robb]

The 8lpm threw me off as well...it's already been established that hyperoxemia is a bad thing...why wouldn't they use low flow O2?

 

[cprted]

Randomization was accomplished by providers drawing sealed envelopes out of a box on arrival at the hospital once a patient was identified for the the study. You open up the envelope and it either says no o2 or give o2 at 8l/min. Patients with sats >95, who were showing signs of hypoxia, or were complaining of being short of breath were excluded from the study and provided o2 as we normally would. Once a provider decided to put a patient into the study who got o2 and who didn't was pretty free of provider bias as best as I can tell.

http://www.ahjonline.com/article/S0002-8703(11)00827-1/fulltext#s0020