Air embolis?

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bwerb

Hoser/English Translator, eh
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Quick question.

During our open water we were shown how to use the compressed tank air to gently blow-dry the rubber regulator protector before afixing it to the regs for storage.

We were told today that using compressed air for this purpose puts us at risk for an air embolis as air is "driven into our bloodstreams through our skin."

My buddy (an RN) said this was close to impossible and was then told that it is a "medically documented fact" that this can happen and anytime you are dealing with compressed air close to your skin it is risky.

So...true or false. If true, how likely is this to occur...I can understand not opening a tank full bore with your hand in the way but am wondering if the way we were doing puts us at risk.

Inquiring minds want to know.:confused:
 
This is the explanation of the air embolism but anyway I cant answer your question or what your buddy told u about dealing with compressed air close to your skin …..
Anyway I will wait like u for an answer form some one who knows better than us ;o)

An arterial gas embolism occurs when a bubble of gas or air causes a blockage of the blood supply to the heart, brain, or other vital tissue. The bubble tend to increase in size as the pressure decrease ( Boyle’s law ), which makes the blockage worse.

When a diver holds his breath or has local air trapped in his lungs during ascent or he was ascending to fast the volume of a gas in the lungs increase due to reduction in ambient pressure. Alveoli can rupture or air be forced across apparently intact alveoli. If air bubbles enter the pulmonary veins, they travel to the to the left side of the heart muscle and then commonly on through the carotid arteries to embolize the brain.
As the bubbles pass into small arteries they reach a point where they can move no further , and they stop circulating.

Arterial gas embolism may occur quickly after surfacing with damage depending on the area involved. There is no way to predict which area will be affected. Symptoms of arterial gas embolism usually occur immediately ar within five minutes of surfacing. Prompt recompression is the only treatment for gas embolism

Sign and Symptoms:

· Chest pain
· Cough or shortness of breath
· Headache
· Numbness
· Weakness
· Dizziness
· Confusion
· Sudden unconsciousness
· Respiratory arrest
· Death

If u want I can add for u how to prevent it and what is the treatment
 
Hi wazza,

Thanks for your input. I really appreciate your response and all it's detail. I understand what you have posted, what I still need to know is if drying your regulator cover with your tank air is the first step on the road to your grave or not.

:confused:
 
bwerb,

A quick answer is...keep on drying your regulator that compressed air. You should keep in mind that if you direct the air into a wet first stage, you will still manage to get water into the works. You might want to direct the air at right angles to the orafice, creating a turbulent flow and a slight vacuum within the first stage opening (Bernouli's Effect).

High pressure can be used to penetrate the skin but this requires certain special circumstances. This is the principle behind auto injector devices. They however, usually require some sort of "seal" between the device and the skin. In fact, it is a high velocity fluid that cuts through the skin when accelerated through a very small opening.

These devices are injecting a fluid which has more mass than the propellant gas.

Technically, should any gas be injected simply under the skin, it is a gas emphysema. The amount used by these injection devices is very small and I truly don't know if any of the gas actually gets under the skin.

If a gas gets into the blood vessels, then it is an embolus. It is now free to travel in the blood stream to distant sites. Trouble occurs when the volume of the gas, as a bubble in circulation is sufficient to disrupt or prevent normal circulation in the affected site.

The organ, and its function also helps determine if a bubble of a particular size will cause a problem. Nervous tissue, by way of it's important functions and limited ability to regenerate would make such an injury more serious. Similarly, a bubble blocking the circulation to the heart muscle would be very serious.

A bubbles location, ie. on the venous side or the arterial side of heart also has some bearing on whether the bubble will do damage. I think that in general, an arterial bubble would be considered to be more dangerous.

Air can also be injected, theroretically, under the skin if it is directed at a break or wound in the skin. Again, an emphysema is the more likely, although very rare result. A relatively low pressure blast could cause a problem. This situation has been documented in the mouth when a dental air syringe (the blower thingy at the dentist) is directed into an extraction site, an incision site, or into an abscess.

It would take EXTREMELY high pressure air directed at an EXTREMELY small area to actually penetrate normal, undamaged skin. Even the air coming out of your tank is NOT at the internal pressure of the tank and it very rapidly expands from the time it leaves the valve to the time it hits an object. Attempting to seal the orafice with a finger will not cause the required resistance because the gas pressure will blow the obstruction off the orafice faster than it can build up sufficient pressure to "inject" the air.

IMHO the information your buddy shared with you is inaccurate or taken out of context.There may be occasions in medical literature in which a fatal injury was caused by a high pressure jet of air penetrating the skin--perhaps an industrial accident or explosion but I doubt that an injury like this has been attributed to drying a scuba regulator with air from the tank.

If there is a reference for such a DIVE injury, I would love to see it. In the event this has happened in the past, the common usage of an air blast in scuba WITHOUT injury is enough for me to "temp fate". Better yet, don't let your regulator get wet in the first place. Bleed the TANK for a moment to clear any water that has gotten into the valve stem.

Any water that has already gotten into the filter element of your first stage is already in there! An air blast will only remove the excess water from the exterior of the reg. Oh, yeah, when doing the air blast thing, it doen't require much skill to aim the air at the reg--with the fingers at the opposite end of the reg if you want to be more careful.

The preceding is my opinion and not to be used as medical fact. I really would love to see the reference to a dive injury caused by this procedure however.

Keep on puffin'. :)

Regards,

Larry Stein
 
Great answer. I may have misstated the regulator cleaning. I am not attempting to clean the regulator itself. Just the first stage dust cap which hangs below the first stage during diving. Just blowing the little drops of water off of the cap before putting it on.:D
 
Issue is the dust cap typically is connected to the first stage in the vicinity of the intake. Since the cylinder air under pressure tends to blow across a fairly broad area, it can force water droplets into the first stage even if not aimed directly at it. I dry my dust cap in this manner, but place a cloth, shirt or dry finger over the intake while doing so.

Best regards.

DocVikingo
 
Just a small idea

my dusk cap is not connected to the regulator so every time I take it of the reg. I put it in my bag and when I want to but it back its clean and dry I don’t have to do anything with it. then after I close the first stage I clean the reg. in fresh water
I think this is a good way, cos I don’t really need the dust cap with me in the water am I right????
 
If you replace the standard dust cap with a ball version (a la Apeks) you can easily dry it with a quick wipe, obviating the need to blast anything. Less risk of blowing water into the first stage, less obnoxious noise, both good enough reasons even without concerning yourself with the injecto-matic potential of high pressure air streams.

I've never heard of anyone suffering from the injury you describe while cleaning their dust cap. I have heard "friend of a friend" reports of it happening to folks carrying tanks by the valve with the outlet pressed against their palm when they accidentally bang the knob against something. Underwater legend, perhaps?

Steven
 
reefraff once bubbled...
If you replace the standard dust cap with a ball version (a la Apeks) you can easily dry it with a quick wipe, obviating the need to blast anything. Less risk of blowing water into the first stage, less obnoxious noise, both good enough reasons even without concerning yourself with the injecto-matic potential of high pressure air streams.

I've never heard of anyone suffering from the injury you describe while cleaning their dust cap. I have heard "friend of a friend" reports of it happening to folks carrying tanks by the valve with the outlet pressed against their palm when they accidentally bang the knob against something. Underwater legend, perhaps?

Steven


and if u have an Apeks reg. but Din ?????
 
wazza once bnoorgled...



and if u have an Apeks reg. but Din ?????

Good point!

Actually, like you, I remove the dust caps when using DIN valves. Having two dust caps for each valve times 2 valves (or 3 or 4) floating around at the end of little strings just seems like a mess. In addition to offending my Hogarthian sense of elegance, they get in the way of the valve stems on my backgas while I'm underwater and I won't put up with that. I was thinking about the average recreational single valve yoke setup when I suggested the ball dust cap.

A blast of air isn't adequate to dry the threading on the male and female ends of DIN connectors (not to mention dangerous that close to the first stage orifice) or their dust caps. If you don't remove the dust caps and leave them on the boat, you're going to need to towel them dry. IMNSHO.

Steven
 
https://www.shearwater.com/products/teric/

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