Oxygen Use in ACS

[deleted92121]

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I have a question regarding the use of supplemental oxygen in ACS situations.

I work as a paramedic both in a busy, non-academic ED and on the trucks. In my state of Pennsylvania, the use of supplemental oxygen in potential ACS situations is supposed to be held so long as the SPO2 reading is above 92%. The protocols cite that recent studies have revealed that administration of supplemental oxygen can potentially increase mortality.

I have asked many of the physicians I work with in the ED and a few agree with this, a few do not. I am curious what other physicians have to say about this, especially ones from perhaps the academic side.

Thanks!

 

[EM2BE]

COPD pts can get worse with increased O2. Is this what they are referring to?

 

[deleted92121]

COPD pts can get worse with increased O2. Is this what they are referring to?

No. I thought that at first too but when we did protocol rollouts in the past year, they said titrate SPO2 to 92%-94% only if initial reading was <92%.

This is a very interesting topic and am curious if anyone else has any thoughts.

 

[ERMudPhud]

Too much 02 AFTER resuscitation is bad

Not exactly the question you are asking but probably where the idea came from. Extra 02 after successful resuscitation leads to worse mortality. As I recall in my last ACLS course they emphasized this point. It doesn't say anything about extra 02 DURING the initial resuscitation


However in peds there is good evidence that it doesn't help and some evidence that it probably hurts.

02 doesn't help with neonatal resuscitation

 

[Aesculapius]

Oxygen is a toxic gas at high concentrations. That is well known. The thought is that giving higher than atmospheric oxygen concentrations (especially if >60% FiO2) to patients that are not hypoxemic results in bad things like free radical formation to tissues that are already ischemic and not in a state to deal with free radicals, leading to increased cell death. I think that this is probably true, but it will be a long while before applying oxygen by NRB at 15 LPM stops becoming an automatic reflex, just like use of antipyretics is a reflex that also may not be well-supported by evidence of benefit.

 

[EM2BE]

Is this a change from the recommended small amount of NC or is it against NRB or both?

 

[shookwell]

There are only 3 randomized studies looking at oxygen use in MIs. There was evidence of harm, but the numbers are pretty small. Basically, oxygen is probably harmful in MIs/ACS, but there isn't enough strong evidence to prove it.

Here is the cochrane review on the subject: http://summaries.cochrane.org/CD007160/routine-use-of-oxygen-in-people-who-have-had-a-heart-attack

We need a large, well-designed, randomized trial to actually see what effect oxygen has on mortality in MIs. Oxygen is a pretty toxic substance at concentrations above 21% or so, and there is really no reason to give it to patients who aren't hypoxic, profoundly anemic, or who have carbon monoxide poisoning.

 

[Hamhock]

There are only 3 randomized studies looking at oxygen use in MIs. There was evidence of harm, but the numbers are pretty small. Basically, oxygen is probably harmful in MIs/ACS, but there isn't enough strong evidence to prove it.

Here is the cochrane review on the subject: http://summaries.cochrane.org/CD007160/routine-use-of-oxygen-in-people-who-have-had-a-heart-attack

We need a large, well-designed, randomized trial to actually see what effect oxygen has on mortality in MIs. Oxygen is a pretty toxic substance at concentrations above 21% or so, and there is really no reason to give it to patients who aren't hypoxic, profoundly anemic, or who have carbon monoxide poisoning.

Yeah - I feel like I spend more time taking oxygen off faces in the ED than just about anything else.

Although most docs are aware that a NRB is not needed for every patient, the scary thing I often see EM docs missing is the hyperoxic intubated patient.

There are only rare cases in my entire medical career that I have seen 100% FiO2 required in the intubated patient.

There are way too many intubated patients in the ED on 100 FiO2 with PaO2 >300 for hours!

HH