Ancient diving theory

[Patience]

This is certainly not current, but I am wondering if anyone knows the theory behind this . . .

My father's sister was diving back in the 60s and 70s. My cousins and I would play on the beach wishing we could join her. As soon as we were all old enough, her sons and I wanted to be certified. The boys were able to complete their certifications, but I wasn't.

My mother's grandfather died of "the bends", or caisson's disease as it was known at the turn of the last century. I was told that because of this, I was more likely to develop DCS, and I was not allowed to dive.

I've subsequently been certified, but wonder why this would ever have been the case. I don't think anything genetic lead to his developing DCS. These guys were the pioneers whose illnesses helped develop our understanding of limits. It's not as if he were following a recreational dive table when he took a hit!

Is anybody familiar with this old rule, or why it would have been so?

 

[sheck33]

Patience once bubbled...
This is certainly not current, but I am wondering if anyone knows the theory behind this . . .

My father's sister was diving back in the 60s and 70s. My cousins and I would play on the beach wishing we could join her. As soon as we were all old enough, her sons and I wanted to be certified. The boys were able to complete their certifications, but I wasn't.

My mother's grandfather died of "the bends", or caisson's disease as it was known at the turn of the last century. I was told that because of this, I was more likely to develop DCS, and I was not allowed to dive.

I've subsequently been certified, but wonder why this would ever have been the case. I don't think anything genetic lead to his developing DCS. These guys were the pioneers whose illnesses helped develop our understanding of limits. It's not as if he were following a recreational dive table when he took a hit!

Is anybody familiar with this old rule, or why it would have been so?

It's highly unlikely that your mother's grandfather's 'hit' would have anything to do with you. This sounds like astrology, because Mars was rising when you were born you are likely to get run over by a car...NOT

But this is not the place to start a discussion about the validity of astrology

 

[Patience]

Thanks for your response.

I'm not worried about it affecting me, I was more curious about why PADI and the dive shop thought it would, lo those many years ago.

His hit was predictible by today's standards -- in fact, it was practically guaranteed. They were constructing a (railway) tunnel beneath a river, and had a problem with flooding. They left the divers down there to deal with a crisis. I guess the good news is that they were able to stop the flooding and saved the tunnel.

 

[BillP]

Patience once bubbled...

I'm not worried about it affecting me, I was more curious about why PADI and the dive shop thought it would, lo those many years ago.

Howdy Patience:

Like sheck33, I can't imagine how your great grandfather's experience would disqualify you from diving. Since I can't think of any rationale for the concern, I can't explain why or how PADI and the dive shop gave you the impression that you couldn't dive just because of your family history. I've noticed over the years that sometimes people's odd beliefs simply defy explanation.

Bill

 

[Dr Deco]

Dear Patience:

“Caisson Workers Disease”

At the turn of the last century, ”Caisson Workers Disease” was definitely a serious occupational disease. During the construction of the Eads Bridge at St Louis over the Mississippi (1869), the problem was handled by restricting the exposure time to pressure as the caissons sank deeper beneath the river. One of the most notable individuals to suffer serious problems was Washington Roebbling, the chief engineer of the Brooklyn Bridge. He became paralyzed while on an inspection tour and remained so for the remainder of his life.

Decompression, a programmed reduction in pressure, was finally used as the method to prevent decompression sickness. The primary problem now affecting “sand hogs” is aseptic osteonecrosis, a debilitating bone disease. This is preventable to a high degree by proper decompression, but the situation is still not under total control.

The procedures used a century ago were not as effective as those employed today. Many are familiar with the fact that deaths were encountered. The exposure conditions are different; dive times are measured in tens of minutes and caisson work is measured in hours. “Compressed air tables” are nothing like those used for SCUBA divers.

Divers are not alike

It was not long ago that if asked, “Does a 5% incidence of DCS on a table meant that if 100 people were exposed, five would get the bends?” Alternatively, did it mean, "If the same individual dived it 100 times, s/he would get five 'hits'?” The standard answer was that it was the same either way. I have argued that all divers are not created equal when it comes to risk of DCS. Other researchers would now agree with me on this issue. Divers do vary in susceptibility and can vary depending upon their activity levels.

Why someone thought that you were more susceptible simply because your great grandfather acquired “the bends” is beyond my understanding.

DCS and Genetics

I have worked for several years (decades actually) with rats all of which come from the same supply house. They are all of similar age, weight, and have been inbreed for generations (probably going back to the Pharaohs of Egypt).:egypt: Do they vary in their response to depressurization? Does a baby cry? Absolutely. I am sure that there is something genetic to a degree , but it pales in comparison to pressure change and activity level.

Dr Deco :doctor: