Jumps at 20.000ft with O2 and health

[joaocorreia 0]

Hello,

Is there health issues with jumping from 20.000 ft with oxygen ? What happens to your body in the process ?


Best regards
Joao Correia

[GLIDEANGLE 1]

Here is a good place to start your research:

http://www.uspa.org/SIM/Read/Section6/tabid/169/Default.aspx#982

The choices we make have consequences, for us & for others!

[billvon 2,380]

>Is there health issues with jumping from 20.000 ft with oxygen ?
>What happens to your body in the process ?

That's a very broad question. But some preliminary stuff:

You care about two things. The first is partial pressure of O2. This determines whether or not you will get hypoxic, and how fast that will happen. The second is total pressure change over time. This determines if you will be at risk for decompression sickness. For 99% of jump aircraft, this is not an issue.

Another important issue is "time of useful consciousness." This is an estimate of how long you will be able to function once you stop using oxygen that gives you a PPo2 (partial pressure of O2) equivalent to sea level.

For example, at 22,000 feet, you have a time of useful consciousness of about 5 minutes (assuming sedentary activity.) That means that if you are on enough oxygen to approximate sea level, and you go off it, your blood will retain enough oxygen to keep you going for about 5 minutes (assuming you're relaxed.) This is why in-plane oxygen is sufficient for jumps up to about 20,000 feet - you stay on O2 until the last minute, then exit, and at that point you have 5 minutes to get to a breathable altitude. (In freefall it takes less than 1 minute to get below 12,500 feet, where there is sufficient partial pressure of oxygen to avoid most hypoxic symptoms.)

There's a lot more to it than that, but those are the basics.

[skydiverek 54]

Quote

Hello,

Is there health issues with jumping from 20.000 ft with oxygen ? What happens to your body in the process ?

Here is what happens when the oxygen flow is not adequate ...:

http://www.youtube.com/watch?v=tXa4w4aYKEk

[MilliniaS 0]

ARE YOU FREAKING KIDDING ME WITH THAT VID????

thank god he didnt pull out a pin while dragging his ass on the aircraft floor.
(among a bazillion other things that could have gone wrong)

one word.... YIKES.


edit to add (among a bazillion other things that could have gone wrong)

"Its such a beautiful day outside, we should thank the leader."

"The leader? Who the hell is that? Some sort of leader?" -Homer Simpson.

[danielcroft 2]

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=2670064;page=1;sb=post_latest_reply;so=ASC;mh=25;

There's the original thread, lots of information & discussion there.

[mjosparky 3]

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The first is partial pressure of O2. This determines whether or not you will get hypoxic, and how fast that will happen.

PARTIAL PRESSURE OF OXYGEN

The quantities of a gas at various altitudes, expressed in percentages of the atmosphere, has little significance. Percentage represents the relative volume of a gas and not its molecular concentration. Molecular concentration, or partial pressure, determines the availability of the gas to the body.

The partial pressure of a gas, in a mixture of gases not interacting with one another, is equal to that pressure that the particular gas would exert if it alone occupied the space taken up by the mixture (Dalton's Law of Partial Pressure).

The total pressure of a mixture of gases is the sum of the pressure of the individual gases composing the mixture.

The body requires hemoglobin saturations of 87-97 percent and arterial oxygen at 60-100mm Hg (millimeters of mercury) in order to function normally. Below this level the body is hypoxic.

The standard pressure at sea level is 760mm Hg. Since oxygen comprises about 21 percent of the air, we would expect the dry air oxygen partial pressure in the lungs to be 159.6mm Hg (760 times 21 percent), but through physiologic processes, the partial pressure of oxygen in the arterial blood is normally about 100mm Hg.

Air inhaled into the lungs enters small air sacs (alveolus) where the exchange of oxygen and carbon dioxide occurs. When the partial pressure of the oxygen is higher than it is in the blood, oxygen molecules are picked up by the hemoglobin molecules. This hemoglobin saturation is approximately 97 percent at sea level.

The atmospheric pressure decrease at 10,000-foot altitude causes 523mm Hg ambient air pressure resulting in 87 percent hemoglobin saturation and 61mm Hg arterial oxygen.

At 15,000 feet (429mm Hg) the hemoglobin saturation is 80 percent (we need 87-97 percent for normal functioning), and arterial oxygen is 44mm Hg (the body requires 60-100mm Hg.).

See attachment 1. (source Flight Surgeon’s Manual)

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Another important issue is "time of useful consciousness."

TIME OF USEFUL CONSCIOUSNESS

The time of useful consciousness is that period between an individual’s sudden deprivation of oxygen at a given altitude and the onset of physical or mental impairment which prohibits his taking rational action. It represents the time during which the individual can recognize his problem and reestablish an oxygen supply, initiate a descent to lower altitude, or take other corrective action. Time of useful consciousness is also referred to as effective performance time (EPT). The time of useful consciousness is primarily related to altitude, but it is also influenced by individual tolerances, physical activity, the way in which the hypoxia is produced and the environmental conditions prior to exposure. Average times of useful consciousness at rest and with moderate activity at various altitudes are shown in Table 1-8. The subjects were breathing oxygen and produced the hypoxic environments by disconnection their masks. If an individual breathing air is suddenly decompressed; his time of useful consciousness is shorter than if he had been breathing oxygen. The PO2 in his lungs drops immediately to a level dependent only on the final altitude, rather than dropping gradually with each breathe of air, dependent on lung volume, dilution of that volume, and altitude.

See attachment 2 (source Flight Surgeon’s Manual)

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Sparky

My idea of a fair fight is clubbing baby seals

[LouDiamond 1]

You took the words right out of my mouth.

"It's just skydiving..additional drama is not required"
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[gusto77 0]

WOW!!! that video was the most horrific thing i have ever seen... Ive had to breath a little O2 before even at 13500 when the plane had to circle the DZ for an extended period (military jump). But to go up to that altitude without proper plannin, equipment, etc..... Horrible

[joaocorreia 0]

Thank you so much for the detailed replies !

Blue skies !
Joao Correia