RMV Spinoff from Accident & Incident Discussion - Northernone - aka Cameron Donaldson

[BRT]

can you provide any studies showing CO2 narcosis from breathing air please?

Nope. do you believe CO2 doesn't build up when skip breathing or not breathing enough while exercising? Do you believe CO2 is not a narcotic gas? I can be narced relatively shallow while exercising and not breathing deeply enough. No proof it is CO2, but several times this has happened. A few really deep breaths stop the sensation.

Edit:I don't think this has anything to do with air vs nitrox..

 

[dmaziuk]

Decompression illness is caused by multiple factors (as you know) and respiration has effects on in-gassing as well as off gassing. Deco models do need to account for multiple factors if they want to be accurate.

The models' job is to get people out not bent. They don't have to be precise or even correct: if they don't get people bent for wrong reasons, they're just fine. The goal of making them more sophisticated is to get even fewer people bent. There are two main problems with that:
1. Adding sophistication trying to model things you don't fully understand has a high chance of back-firing, especially if the model isn't precisely correct to begin with.
2. If the number of DCS incidents is already low enough to be caused (or explained away) by factors you don't model, like quirks in individual physiology, your additions won't make any difference to the outcome.

 

[StefinSB]

No.
Elevated carbon dioxide can cause not only narcosis but DCI. Why? Because elevated levels of carbon dioxide can cause blood vessels to dilate enhancing delivery of inert gas to tissues. Also elevated levels can lower the threshold for oxygen toxicity. Factors that can increase the divers' carbon dioxide levels include the increased dead space of breathing equipment and the additional work of breathing dense gas underwater, and activity level among other things.

Thank rsingler and yourself for the nice explanation. One thing I am not sure I get. Can you please explain what exactly you mean by “dead space of breathing equipment”?

 

[Vicko]

Co2 headache is one of Co2 poisoning symptoms and surprisingly if you skip breath you usually get a headache.
Anyone who claims it's hard to get Co2 poisoning at depth on OC has never dived in a current or done some work bellow 30 meters.
What is O2 efficiency? As a free diver I heard the term thrown around but no one quite explained it to me, faster O2 absorption, faster Co2 dissipation? Both of those can't be achieved with different breathing methods as you can't change your blood by breathing differently. All yoga and breathing techniques do is change the way your body responds to low O2/ high Co2 in the blood. They don't actually change the amount of the gas that your blood absorbs...

 

[Compressor]

“dead space of breathing equipment”?

Sure I'd be happy to. Dead space of breathing equipment is an area where gas is not exchanged. Dead space is the volume of a breath that does not participate in gas exchange (oxygen delivery and carbon dioxide elimination). It is ventilation without perfusion. In the lungs, physiologic or total dead space is the sum of anatomic dead space (equipment: inside mouth piece so I think its a small amount) and alveolar dead space (just because it reached your lungs and alveoli at the gas exchange level, it does not mean it will be exchanged if there is an issue).

Let see if this helps:

Source: Physiology Glossary: Physiologic Dead Space & Ventilation Rates

and

Source: Overview of Respiratory Function: Ventilation of the Lung | Veterian Key

 

[cerich]

Nope. do you believe CO2 doesn't build up when skip breathing or not breathing enough while exercising? Do you believe CO2 is not a narcotic gas? I can be narced relatively shallow while exercising and not breathing deeply enough. No proof it is CO2, but several times this has happened. A few really deep breaths stop the sensation.

Edit:I don't think this has anything to do with air vs nitrox..

you said air, and CO2 narcosis is a defined condition. medically versus what I now see you are talking about regards inert gas narcosis. The medical term definition is why I asked you for any studies showing air as an issue, because it's considered a high PPO2 issue.

I am just trying to establish what you are trying to express.

 

[cerich]

Sure I'd be happy to. Dead space of breathing equipment is an area where gas is not exchanged. Dead space is the volume of a breath that does not participate in gas exchange (oxygen delivery and carbon dioxide elimination). It is ventilation without perfusion. In the lungs, physiologic or total dead space is the sum of anatomic dead space (equipment: inside mouth piece so I think its a small amount) and alveolar dead space (just because it reached your lungs and alveoli at the gas exchange level, it does not mean it will be exchanged if there is an issue).

Let see if this helps:
View attachment 510932
Source: Physiology Glossary: Physiologic Dead Space & Ventilation Rates

and

View attachment 510933

Source: Overview of Respiratory Function: Ventilation of the Lung | Veterian Key

and snorkel, full face mask, second stage, loop, canister or counter lungs of equipment are "potential equipment dead space" for diving use . obviously all of those won't be in use at the same time, the last three CCR related go together however.

 

[StefinSB]

Sure I'd be happy to. Dead space of breathing equipment is an area where gas is not exchanged. Dead space is the volume of a breath that does not participate in gas exchange (oxygen delivery and carbon dioxide elimination). It is ventilation without perfusion. In the lungs, physiologic or total dead space is the sum of anatomic dead space (equipment: inside mouth piece so I think its a small amount) and alveolar dead space (just because it reached your lungs and alveoli at the gas exchange level, it does not mean it will be exchanged if there is an issue).

Let see if this helps:
View attachment 510932
Source: Physiology Glossary: Physiologic Dead Space & Ventilation Rates

and

View attachment 510933

Source: Overview of Respiratory Function: Ventilation of the Lung | Veterian Key

Thanks! That clarifies it.

 

[Celt]

I don’t know that. Any data or link to a study that support your claim, this more efficient oxygen use through nasal than mouth?

From my understanding of high altitude breathing, people that live in high altitude have either higher density of hemoglobin in their blood as the case of the study on people who live in Andes, "Andeans counter having less oxygen in every breath by having higher hemoglobin concentrations in their blood," as quoted from the article below

https://www.google.com/amp/s/relay....e/2004/02/high-altitude-adaptations-evolution

Or breathe faster, as the case of people who live in Tibet. “Tibetans compensate for low oxygen content much differently. They increase their oxygen intake by taking more breaths per minute than people who live at sea level.”

When I hiked up Kilimanjaro (19,341 feet) I did experience with increase breathing rate. However after 3-4 days high altitude acclimation at around 13,000 to 15,000 feet, before summiting, my breathing rate calmed down to normal level. I was told that my body was adjusting to the low oxygen environment by producing more hemoglobins in the blood.

Apart from the fact that no animal other than humans breath through the mouth the nose warms and filters the air and slow nasal breathing stimulates the production of nitric oxide inside the paranasal sinuses. When we breath through the nose nitric oxide follows the airflow to the lung and increases the oxygen uptake in the blood. Mouth breathing was said to be a curse for a persons health by yoga masters 100 years ago and today science has proved them right. According to Jon Lundberg, professor of pharmacologics at the Karolinska Institute in Stockholm, large amounts of nitric oxide are constantly released in the nasal airways of humans.

 

[tursiops]

Apart from the fact that no animal other than humans breath through the mouth the nose warms and filters the air and slow nasal breathing stimulates the production of nitric oxide inside the paranasal sinuses. When we breath through the nose nitric oxide follows the airflow to the lung and increases the oxygen uptake in the blood. Mouth breathing was said to be a curse for a persons health by yoga masters 100 years ago and today science has proved them right. According to Jon Lundberg, professor of pharmacologics at the Karolinska Institute in Stockholm, large amounts of nitric oxide are constantly released in the nasal airways of humans.

Wow....the things one can learn from the internet!