Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

Comment on With Conflicting Evidence, What Should We Do? – Oxygen


In the comments to With Conflicting Evidence, What Should We Do? – Oxygen is the following from Dr. Brooks Walsh.

The importance of this study is that it may suggest that hyperoxia may be beneficial at different points in critical illness, and that we need to be careful before acting too broadly.


The way to find out what works is with prospective studies.

We do not have any shortage of cardiac arrests to study. We only have a shortage of research and therefore a shortage of understanding.

We should not attempt to make up for that ignorance with wishful thinking.

Homeopathy, epinephrine, chiropractic, oxygen, Reiki, amiodarone, prayer, lidocaine, acupuncture, vasopressin, et cetera. There is no shortage of possible treatments that lack evidence of benefit.

Where do we start?

Homeopathy probably has more research than all of the other treatments combined.

Howevere, homeopathy is just playing the numbers. There is no real treatment, but if we study a placebo enough times, there will be some statistically significant results.

This is just the same as flipping a coin. If we flip a coin enough times, we will produce a series of heads that is so long that it will have a p value that has an impressive bunch of zeroes in it.

Image credit. Click on image to make it larger. Below is the mouse-over text from this – xkcd 882.

So, uh, we did the green study again and got no link. It was probably a–‘ ‘RESEARCH CONFLICTED ON GREEN JELLY BEAN/ACNE LINK; MORE STUDY RECOMMENDED!


The important point is to pretend that the other studies do not matter. Except that the other studies do matter. All that is being done is throwing feces at a wall and hoping that something sticks.

We have been pretending that, with our understanding of physiology, we are too smart to have too study oxygen.

We have been very arrogant and very stupid.

We haven’t even bothered to find out how dangerous our treatments are.

Perhaps there is an analog to the past studies that looked at the treatment of sepsis. Initial studies of sepsis therapy, using aggressive fluid resus and pressors, were conducted in the ICU, hours after admission. Although these studies were based on strong physiologic evidence, the clinical studies were negative. However, when these same interventions were started in the ED, minutes after arrival, we found a huge drop in mortality. Timing matters.


I should have linked to an mp3 recording of Dr. Mervyn Singer pointing out that hypoxemia is probably not as dangerous as we have been told.[1]

Dr. Singer also has a presentation pointing out the problems with catecholamines in sepsis and questioning the research showing benefit from dopamine.[2]

Dr. Singer raises some interesting questions. the only way to find out the answers is to do the research, not to claim that a lack of proof of harm is evidence of benefit.

Very few treatments have been proven to be harmful, so we could use anything. If enough people follow suit, we have a standard of care that probably is much more harmful than we image and probably not helpful at all.

And so it may be with oxygen. It doesn’t help that most of the studies out there are retrospective, and so are suggestive, but they require confirmation with prospective trials. Some “common-sense” changes in practice have already been implemented, but we need to be careful before extending this reasoning to all clinical situations.


We do not have any high-quality data of benefit. We have a lot of anecdotes of kitchen sink treatment.

When we throw the kitchen sink at the patient, sometimes the patient dies and sometimes the patient lives. We cannot tell if there is any benefit from the kitchen sink, or from any element of the kitchen sink, but we don’t let that stop us.

Our ignorance is unstoppable.

We already have an avalanche of excuses for continuing to harm patients.

We need to stop making excuses and figure out what we are doing.


[1] Permissive hypoxaemia – the way forward
2011, Critical Care, Manchester Critical Care Conference
2011-04-28 at 09:30
Dr. Mervyn Singer
Free Emergency Medicine Talks
Free page with link to free mp3 of presentation.

[2] Catecholamines Should Be Banned
2009, Critical Care, Manchester Critical Care Conference
2009-04-24 at 15:45
Dr. Mervyn Singer
Free Emergency Medicine Talks
Free page with link to free mp3 of presentation.