Is it safe for me to fly? I really need to get home.

[VikingDives]

Air gas embolism is simply forcing air from your lungs into your circulatory system.

It has nothing to do with PFOs or the off-gassing of nitrogen.

The only way you, as a scuba diver, could possibly get AGE in an aircraft would be if your flight was at say 40,000 feet and you were holding your breath and the cabin suddenly depressurized and you continued to hold your breath. Then you could get an AGE.

So remember kids, don't hold your breath while your plane falls apart in flight.

 

[uncfnp]

Air gas embolism is simply forcing air from your lungs into your circulatory system.

It has nothing to do with PFOs or the off-gassing of nitrogen.

The only way you, as a scuba diver, could possibly get AGE in an aircraft would be if your flight was at say 40,000 feet and you were holding your breath and the cabin suddenly depressurized and you continued to hold your breath. Then you could get an AGE.

So remember kids, don't hold your breath while your plane falls apart in flight.

I do not think that is correct. AGE from lung over expansion is one form but can also occur with a right to left shunt. PFO can increase this risk.

 

[formernuke]

What if they unknowingly have a PFO? Is it possible then?

No

 

[duke dive medicine]

Look up arterial gas embolism. Yes, permanent injury can happen.

This is a common misconception in newly trained divers since open water curricula don't allow for much time on differentiating diving injuries. AGE results when air is trapped in the lungs and there's a reduction in ambient pressure, like if a diver holds his/her breath and ascends. Flying after diving can place a diver at risk of decompression sickness, which is where residual dissolved inert gas forms bubbles in the blood and/or body tissues which then cause symptoms. Ascent to altitude decreases the ambient pressure around a diver, which means there's less pressure holding the residual gas in solution. It's the same gas law at work as when you're ascending in the water.

Lol, this doesn’t play in this scenario, unless his flight is in the space shuttle.

Paradoxically even less likely than flying. The Shuttle cabin was pressurized to atmospheric pressure with air.

Best regards,
DDM

 

[L13]

If your tissues are at equilibrium at sea level, your GF99 at 8000 ft would be about 1.3%, not 18%.

You are right, when I calculated GF for Tissue 16, I forgot to include water vapor when calculating sea level saturation (Again! Embarrassingly, I did that once before debating GF's with you).

My calculation of GF99 for tissue 6 with 10% excess N2 on the Garmin was similarly flawed and overstated. The correct answer for that is GF99~=10% at 8k ft. That is for instant teleportation, it will be dropping during the climb out.

In any case, I still stand behind my original statement. After a week of intensive diving in Cozumel, and a 41 hour surface interval before flying, my Garmin showed excess nitrogen was 5%. Are you suggesting that the 41 hour surface interval was too short? (that would be GF99=11% at 8k if it was in tissue 16, which it probably was).

If a Garmin shows less than 20% excess N2 shortly after 5 dives over 3 days and dropping 3-4% over the next hour (it will slow down), I would be confident that it would be below 10% in 12 hours, and that it would be safe enough to fly. Depending on the actual profile of the dives, those conditions likely may not be met. Were the dives mostly close to the max depth, or mostly shallow with a short deep excursion near the beginning? OP made it sound like there was relatively little time at depth, but depth plots might show different.

Following the Navy ascent guideline for that Duke dive (60 fsw/55 min) would yield a 14% GF99 at 8k ft. I would not want to fly with an 18% value.

In your previous post, you said their GF was 38%?

 

[duke dive medicine]

I do not think that is correct. AGE from lung over expansion is one form but can also occur with a right to left shunt. PFO can increase this risk.

That's where the medical profession in general muddies things a bit . As you pointed out, technically anything that's in the blood vessels that doesn't belong there is an embolus. If venous gas emboli pass through a PFO or other shunt, they become arterial gas emboli from a medical terminology point of view. For differentiation purposes in diving injuries though, that is not considered arterial gas embolism. It's sometimes referred to as decompression illness vs decompression sickness.

Best regards,
DDM

 

[Superlyte27]

This is a common misconception in newly trained divers since open water curricula don't allow for much time on differentiating diving injuries. AGE results when air is trapped in the lungs and there's a reduction in ambient pressure, like if a diver holds his/her breath and ascends. Flying after diving can place a diver at risk of decompression sickness, which is where residual dissolved inert gas forms bubbles in the blood and/or body tissues which then cause symptoms. Ascent to altitude decreases the ambient pressure around a diver, which means there's less pressure holding the residual gas in solution. It's the same gas law at work as when you're ascending in the water.


Paradoxically even less likely than flying. The Shuttle cabin was pressurized to atmospheric pressure with air.

Best regards,
DDM

Good point. Completely forgot the shuttle was pressurized. As a pilot, I’m a bit embarrassed that I forgot.

 

[inquis]

Following the Navy ascent guideline for that Duke dive (60 fsw/55 min) would yield a 14% GF99 at 8k ft.

In your previous post, you said their GF was 38%?

The 8k GF of 38% was after 3 hrs and was associated with multiple DCS cases. The 14% value was after 14.25 hrs (which was dictated by the Navy ascent table).

 

[inquis]

In any case, I still stand behind my original statement. After a week of intensive diving in Cozumel, and a 41 hour surface interval before flying, my Garmin showed excess nitrogen was 5%. Are you suggesting that the 41 hour surface interval was too short? (that would be GF99=11% at 8k if it was in tissue 16, which it probably was).

Your original statement was not about "excess nitrogen", it was about looking at the GF on a Garmin or Shearwater computer. Furthermore, that and the tissue graphs would necessarily be giving the sea level information. Your original statement (emphasis mine):

with my Garmin (or a Shearwater and several others) I would look at the SurfGF at the end of each dive (especially the most recent ones) and the current tissue graphs. If GF's were << 50% and the current tissue graphs were < 20% and looked like they would be <10% by the flight, I would probably personally take the risk (but you shouldn't).

If you fly with a 10% sea-level GF, it is highly likely that you will develop DCS -- thus the "absolutely do not do this" in my initial posting. For an indication of the kind of risk flying with a 10% sea-level GF would entail on that single Duke dive, that is reached a mere 69 minutes after surfacing.

 

[MidOH]

IIRC, my Terric did show me off gassing, or something, on the plane.

Even though I had no more than sea level, in me.

I'll have to snap a pic next time.