Vortex Incident

[jhayes75]

The number one rule in Scuba, never hold your breath. Regardless if he were buddy breathing, or sharing air, you never hold your breath. Buddy breathing between students is common. I can't tell how many times my instructor stressed to never hold your breath during training, but it seemed like every 5 minutes or so.

Apparently he held his breath on the ascent and sustained a lung-over expansion injury.

IMHO he shouldn't have been buddy breathing with a student. He is a certified diver and even though he was being re-certed, is entitled to do what he wants, his daughter is a student.

[zaberman1]

We were there and had two rescue trained divers who were actively involved in taking care of the diver. He was being re-certed at the same time that his daughter getting her open water certificate. They were making an ascent buddy breathing. He was a healthy non-smoker who was making a buddy-breathing ascent. Apparently he help his breath on the ascent and sustained a lung-over expansion injury.

IMHO he shouldn't have been buddy breathing with a student. He is a certified diver and even though he was being re-certed, is entitled to do what he wants, his daughter is a student. If her OWSI wanted to teach her to buddy breath, then he should have been the one doing it with her, not her NON-INSTRUCTOR father. Hearing her scream "Is my daddy going to die!" and seeing him having his wetsuit cut off before being wisked off in a rescue chopper is not going to give her warm fuzzy feelings about SCUBA diving.

Call me an insensitive meanie, but their OWSI had no business letting a student partner up with anyone other than himself or another professional for something as potentially dangerous as a buddy breathing ascent in this day and age when octopi are universally available. (Not to be construed as a swipe against using or teaching buddy breathing as an option.)

I'm sure that there OWSI feels terrible and since his student wasn't hurt, he won't be under any heat in that respect, but I shouldn't wonder if the issues listed above won't be raised.

I really don't want to sound insulting or rude but I do have a couple of comments.

1. It is not uncommon for students to be involved in skills requiring the use of a buddy. Lets face it, most divers will not dive with an instructor after the course. Since it was the girls father, I don't think its unreasonable to include him in the skill given that they will probably be dive buddies.

2. Are you sure that he actually held his breath? There are pre-existing medical conditions that could make a diver prone to lung over expansion (asthma). Buddy breathing skills require both divers to exhale when the regulator is out of their mouth, giving the instructor the benefit of the doubt, it seems there might have been something else going on or maybe the ascent was a little quick? I would really like to see the details...

3. Where in the spring were they performing the skill?

4. Thank you for providing us with some important details about the incident. That being said (i'm sure you can talk to the rescue divers about this), its very important to avoid speculation/implicitly assigning blame ESPECIALLY if you were at the scene of the accident. Any statement you make can be used in court, potentially against the instructor. More importantly, it distracts from investigating all potential causes of the incident. Any student/diver/etc under the instructor's supervision is his/her legal responsibility and its best to avoid making comments absent complete facts. I am singling your post out because your opinion may be a bit more official than anyone else's. Did you give a police report?

I would have sent you a pm but I think its VERY important for everyone to understand that some information is a little too sensitive in a public forum.

All the best,

Zach

[evac93rd]

I really don't want to sound insulting or rude but I do have a couple of comments.

1. It is not uncommon for students to be involved in skills requiring the use of a buddy. Lets face it, most divers will not dive with an instructor after the course. Since it was the girls father, I don't think its unreasonable to include him in the skill given that they will probably be dive buddies.

2. Are you sure that he actually held his breath? There are pre-existing medical conditions that could make a diver prone to lung over expansion (asthma). Buddy breathing skills require both divers to exhale when the regulator is out of their mouth, giving the instructor the benefit of the doubt, it seems there might have been something else going on or maybe the ascent was a little quick? I would really like to see the details...

3. Where in the spring were they performing the skill?

4. Thank you for providing us with some important details about the incident. That being said (i'm sure you can talk to the rescue divers about this), its very important to avoid speculation/implicitly assigning blame ESPECIALLY if you were at the scene of the accident. Any statement you make can be used in court, potentially against the instructor. More importantly, it distracts from investigating all potential causes of the incident. Any student/diver/etc under the instructor's supervision is his/her legal responsibility and its best to avoid making comments absent complete facts. I am singling your post out because your opinion may be a bit more official than anyone else's. Did you give a police report?

I would have sent you a pm but I think its VERY important for everyone to understand that some information is a little too sensitive in a public forum.

All the best,

Zach

You raise some excellent points. Here are my responses.

1. I agree that students by the very nature of things must buddy up to perform skills. I do feel and I did point out that in this case "buddy breathing in 2010" I think it should have been the instructor and not her Dad. It's a little too easy for a buddy breathing diver in the excitement of an OOA ascent to forget that little dribble of air after taking the two breaths.

2. The follow-up that we got the next day pointed to this. His wife was telling everyone present that he was a healthy non-smoker w/o any respiratory problems.

3. They were ascending from the area of the 20' platform and the diving bell, so the maximum ascent could not have been more than 25'.

4. I did point out that it was IMHO. I made the statements here solely as opinion to be shared on this blog. Both of our Instructors that tended to the injured diver filled out PADI incident reports. Your point about speculation and future legal implications however is well taken and I appreciate your advise.

[zaberman1]

Thanks evac, I appreciate the update!

I know that a lunger over expansion injury can occur at shallow depths but does anyone know if there is a general rule for how much a lung can expand before that critical point? Or, are there too many variables to even draw such a generality?

25 ft, thats about 1.76 ata (seemingly enough to cause catastrophic expansion). Could heavy work/hyperventilation (skills demonstration) increase the tolerance of lung overexpansion injury?

[jhayes75]

Thanks evac, I appreciate the update!

I know that a lunger over expansion injury can occur at shallow depths but does anyone know if there is a general rule for how much a lung can expand before that critical point? Or, are there too many variables to even draw such a generality?

25 ft, thats about 1.76 ata (seemingly enough to cause expansion). Could heavy work/hyperventilation (skills demonstration) increase the tolerance of lung overexpansion?

Correct me if I am wrong, but if you filled a balloon at 33ft and released it, wouldn't it expand twice its size upon reaching the surface.

http://aquaviews.net/an-introduction...-1-boyles-law/

[zaberman1]

Correct me if I am wrong, but if you filled a balloon at 33ft and released it, wouldn't it expand twice its size upon reaching the surface.

An Introduction to Scuba Gas Laws – Part 1 : Boyle’s Law|Aquaviews – Online SCUBA Magazine

Yes.

Maybe I was misunderstood. How much can one's lung expand before the breaking point?

At 25 ft it would be 1.76 x because the air is 1.76 x denser, 1/1.76 volume in container, etc. I know the concept and application, I am curious as to how much expansion is necessary for there to be a problem.

[bamamedic]

I don't believe the lung is very tolerant of overexpansion at all....let me ask around and see if I can't find a source for that, though

[TSandM]

Well, I don't know any statistics on how much pressure the lung can take before it bursts -- somebody with more ambition than I have could search the Rubicon Repository to see if such a paper exists. But I do know that, when we have people on ventilators and the peak pressure being applied by the vent gets up to 40 torr, we start worrying a lot about pneumothorax. 40 torr is about 5% of an ATA, or not quite 2 feet of sea water. Now, this is not directly able to translate to normal lungs, because the ones we're ventilating are sick and stiff, but even if you assumed normal lungs were twice as compliant, we're still talking only 4 feet of water. So, if you've taken a full breath and hold it for very long at all, you're at significant risk.

[Hetland]

The most dangerous place for over-expansion is the last 30 feet because the difference in pressure is greatest between 0 and 30.

Also, I understood that it was the individual alveoli that go first. This is where gas and blood make their meeting and departures. Even if the lung, as a unit, did not mechanically fail, each ruptured alveoli would decrease the efficiency of gas exchange, and probably add fluid to the interior of the lung, further screwing the process.

Please correct me if I'm wrong.

[Tom Smedley]

Through the years I have always heard that four feet is sufficient. At about .445 psi per foot seawater or .432 psi freshwater or .5 psi per foot if you add close enough for government work that would give you about 2 psi overpressure. Does anyone want to volunteer for in vitro testing?

only 4 feet of water. So, if you've taken a full breath and hold it for very long at all, you're at significant risk.