Excess oxygen during surgery linked to higher risk of organ damage

Medical Xpress / British Medical Journal / The BMJ ^ | Nov. 30, 2022 | David R McIlroy et al

[ckilmer]

Is your point that the problem was with pure oxygen but not with concentrated oxygen?

[ckilmer]

Is concentrated oxygen like you get with hyperbaric oxygen therapy —safe?

[gas_dr]

Technically hyperbaric can be low inspired content. Using pressure drives it to tissue level instead of hemoglobin delivered. Hyperbaric for wound actually counts on free radicals to sterilize the wound.

The injury from superoxide tx takes days to develop. Although damage can be chemically measured in 12 hours or so actual fibrosis and clinically significant fibrosis takes a week or so.

When I give a general anesthetic there are reasons to bump the inspired fraction a little. Room air is 21% oxygen. I usually run patients around 30% all things being equal. But 60% is the real line you only cross if you have to

[Radix]

I have met many Nurses who insist on providing 100% O2 which I agree with you is ordinarily unnecessary. Sixty percent makes complete sense to me. In the Trauma Bays 100% is pretty much the norm, but once stabilized if the ETCO2 is acceptable and ABG reveals PAO2 and PACO2 (as well PaO2 and PaCO2) is normal then lowering the FIO2 to even 21% makes sense. I did it all the time though it can freak Nurses out.

As well, I have met Nurses who believe that a CO2 Retainer should not be provided supplemental Oxygen. Such completely misunderstand the problem. I knew one Nurse who constantly dropped the FIO2 once she heard ‘retainer.’ She killed one Patient after I left for the day. That one was terminal, but dying of Oxygen starvation was not right. She was too stupid to reason with. She accelerated that expiration only slightly, but I watched her ever after until I left or she was terminated.

I don't know what people think Hyperbaric is, but probably they ought not discuss it from absolute ignorance.

[blueplum]

IIRC, excess O2 can dry out the coating on avoili, a fatty substance called the pulmonary surfacant that keeps avioli from collapsing. (also dried out by smoking)

related, from 2016:
Too Much Oxygen: Hyperoxia and Oxygen Management in Mechanically Ventilated Patients
https://pubmed.ncbi.nlm.nih.gov/26820270/