Question Long term effects of O2 pulmonary toxicity

[steinbil]

After all the recent discussion of CNS limits, and some confusion regarding limits for pulmonary toxicity and OTUs, I have a question about the long term effects of elevated O2 exposure on the lungs.

Is the lung damage from O2 pulmonary toxicity fully reversible? Does it depend on the severity of the damage? What is the chance of permanent damage from high O2 exposure? Does this damage stack up over time, even after recovery?

Any data on the lung health and function of older divers with a long career in diving behind them? Maybe something from the commercial diving industry?

@Imla @Wookie @Superlyte27 @PfcAJ @Duke Dive Medicine

 

[Superlyte27]

After all the recent discussion of CNS limits, and some confusion regarding limits for pulmonary toxicity and OTUs, I have a question about the long term effects of elevated O2 exposure on the lungs.

Is the lung damage from O2 pulmonary toxicity fully reversible? Does it depend on the severity of the damage? What is the chance of permanent damage from high O2 exposure? Does this damage stack up over time, even after recovery?

Any data on the lung health and function of older divers with a long career in diving behind them? Maybe something from the commercial diving industry?

@Imla @Wookie @Superlyte27 @PfcAJ @Duke Dive Medicine

Hard to say. Almost everyone I knew in the comm dive industry had very bad habits like drinking, smoking, women, etc. Was their lung issues due to longterm oxygen exposures or long term bad health decisions? Not sure.

 

[tridacna]

Hard to say. Almost everyone I knew in the comm dive industry had very bad habits like drinking, smoking, women, etc. Was their lung issues due to longterm oxygen exposures or long term bad health decisions? Not sure.

I don’t consider “women” to be a bad habit. Also wonder what their effect on your lungs are?

 

[Imla]

From the information given to me at the chamber before starting my series of HBO treatments they said that some experience a 3% loss in pulmonary function permanently. Currently my brain is a bit mush, so consider it with a grain of salt.
Incidentally, one of the treatments currently in testing for long covid is hyperbaric oxygen.

 

[Sevenrider860]

There is a point where damage from POT is irreversible. But I think it is very difficult to determine where that point actually is. Special Operation Forces commonly use Oxygen rebreathers and there was a study on Oxygen Toxicity. Specific to POT, I copied excerpts from the study below.

Oxygen Toxicity and Special Operations Forces Diving: Hidden and Dangerous

Pulmonary oxygen toxicity (POT) can be divided into two phases. The first exsudative phase is marked by local inflammation with capillary and endothelial edema, a decrease of type I alveolar cells, and an influx of inflammatory cells (Miller and Winter, 1981; Bryan and Jenkinson, 1988; Demchenko et al., 2007). These changes are reversible and the lung returns to its normal state if the inspired oxygen pressure is reduced below 0.5 ATA. In the following proliferative phase fibroblasts and type II alveolar cells infiltrate the inflamed endothelia. With continuing inflammation, this ultimately leads to alveolar fibrosis and a four- to fivefold increase of thickness of the air-blood membrane and, as a consequence, loss of diffusion capacity (Kapanci et al., 1972; Robinson et al., 1974). These changes are irreversible.
...
In a recent 20-year longitudinal cohort study, we found no significant changes in pulmonary function and diffusion capacity of SOF divers compared to other Navy divers or non-divers. Yearly exercise tolerance testing shows VO2 max values regularly surpassing 50 ml/kg/min and all divers remain fit for diving duties during their career. This may be due to either sufficient “recovery” time between extreme dives, or because exposures are not severe enough to cause irreversible damage.


"

 

[Capt Jim Wyatt]

Below is an answer from a hyperbaric physician who did his fellowship at Duke:
================
As for Pulmonary Oxygen Toxicity existing....it most definitely does exist and I have seen it several times and had it at least twice on exposures that were significant.

We can measure it in subjects using pulmonary function tests and the results are repeatable. On those who press forward and continue an exposure, we can even tell you what the cellular pathology will be at autopsy.

There were millions of Americans alone that died of it during COVID (Alpha wave) when we couldn't dial the FiO2 on the vents down. It takes 3-4 days at 100% at 1 ATA to kill a person... unfortunately... To quote a famous scientist: "Science doesn't care what you believe..."

 

[tridacna]

Below is an answer from a hyperbaric physician who did his fellowship at Duke:
================
As for Pulmonary Oxygen Toxicity existing....it most definitely does exist and I have seen it several times and had it at least twice on exposures that were significant.

We can measure it in subjects using pulmonary function tests and the results are repeatable. On those who press forward and continue an exposure, we can even tell you what the cellular pathology will be at autopsy.

There were millions of Americans alone that died of it during COVID (Alpha wave) when we couldn't dial the FiO2 on the vents down. It takes 3-4 days at 100% at 1 ATA to kill a person... unfortunately... To quote a famous scientist: "Science doesn't care what you believe..."

“Millions” of Americans died because they couldn’t dial the FiO2 on the vents down? Something seems wrong with this statement.

 

[Heat Miser]

women, etc. ,,,, long term bad health decisions?

 

[Superlyte27]

Below is an answer from a hyperbaric physician who did his fellowship at Duke:
================
As for Pulmonary Oxygen Toxicity existing....it most definitely does exist and I have seen it several times and had it at least twice on exposures that were significant.

We can measure it in subjects using pulmonary function tests and the results are repeatable. On those who press forward and continue an exposure, we can even tell you what the cellular pathology will be at autopsy.

There were millions of Americans alone that died of it during COVID (Alpha wave) when we couldn't dial the FiO2 on the vents down. It takes 3-4 days at 100% at 1 ATA to kill a person... unfortunately... To quote a famous scientist: "Science doesn't care what you believe..."

Still anecdotal, even if by a physician

 

[tridacna]

Still anecdotal, even if by a physician

So we are now to believe that millions of Covid-19 stricken Americans died on ventilators that were unable to deliver appropriate FiO2 levels. Was this doctor named Ladapo? This isn't anecdotal. It's pure BS.