A TALE OF TWO SCUBA DEATHS (invitation to further discussion)

[Diver0001]

I did a quick search here on Scubaboard but haven't found a thread that discusses the possible events of Lynne's disappearance. I assume the discussion is on another social media such as Facebook or other scuba forum.

It strikes me personally that a diver who's skill and training is beyond reproach then has a scuba accident. What is a more chilling implication for the rest of us is that it can happen to anyone, including us. But it does remind me of two other instances of other very experienced divers having fatal accidents.

When I first certified for scuba and found Scubaboard a highly accomplished and very well known diver Wes Skiles had just died in a scuba accident. HIs pictures and videos are published in magazines such as National Geographic. As the original articles indicate he had gone on a routine dive and then failed to surface. As a highly experienced cave diver and whose buoyancy control was legendary it was hard to believe that a routine dive would be the one he has a problem with. But later there was an article that his wife was suing the rebreather company. It seems that even for a diver with thousands of dives that a new activity also makes you a newbie for that one activity.

About two years ago Scubaboard lost another moderator when Quero had a scuba accident. That thread and discussion about what my have happened lead to 93 pages and just over 900 posts.

Just to be clear, Moderators on Scubaboard are generally very committed divers but they are not necessarily chosen for their diving skills. Moderators are chosen for their real-world and people skills (although some users may not believe it.... LOL).

That's not to say that Lynne and Marcia (Quero) were not excellent divers. I personally believe that they were, and I know from first hand experience that TSandM definitely was.

Are the moderators on Scubaboard the most experienced and best divers on the board? NO. I don't believe we are. Some are outstanding divers or outright experts in their field but we're primarily here for our ability to herd cats.

The most common thread for all three accidents is that the cause of death listed is drowning. Personally as a medically trained physician I view drowning in two different categories. The first is an actual scuba related drowning where the sport itself causes the drowning. This may be a medical consequence of scuba such as DCI or AGE as the triggering event. Or it can be something that happens while diving, such as entanglement or poor dive execution as in the case cited above. The second cause of drowning while diving is actually unrelated to diving but is a consequence of an underlying medical condition such as a heart attack. I view such accidents as slightly different because it is not actually due to a scuba related mistake, but you just happen to be diving when the medical condition occurs. But since in both instances the person dies while underwater the listed cause of death is drowning.

Of course the cause of death is listed as drowning. That's like shooting on an open goal for the medical examiner. The lungs are full of water, the patient is dead, they were scuba diving... NEXT PLEASE. That doesn't mean that the nuances of what LEAD to the drowning will surface from the autopsy? Of course not.

We can be very sure in this case that there is no question regarding the diver's skill or any other issues with poor planning or poor execution of the dive plan. That leaves either a sudden medical condition or just bad luck. The two things that are classic for loss of consciousness are either cardiac related such as heart attack or neurologic such as stroke. Any speculation to what medical condition at this point is pure speculation and conjecture. It could have been any number of different thins. As for bad luck without knowing what happened it also becomes speculation and conjecture. She may have drifted back and was sucked into the down draft again. But who knows?

Nobody. I have my own pet theory and I've heard the theories of others but "bad luck" fits. If something serious and medical occurs under water then Murphy got you. A non diving friend of mine who met Lynne once told me that if Murphy got too close that she would have strangled him until his eyes popped out.

Do I think she went down fighting? Absolutely

But Murphy won this round.

My dad used to say, "live every day like it will be your last." I try to do that as much as possible. To me it's better than Henry David Thoreau's "most men lead lives of quiet desperation." I am so thankful that I have been able to experience the thrill of breathing underwater. To see the fish, the coral, the turtles, shark, and all the other creatures that live in the sea up close. I have a passion about diving that is in my heart, my soul, and I long and dream for the next opportunity to dive. Lynne shared that passion. But why God called good people prematurely is beyond my humble means of comprehension. But for the brief and limited time I got to know a little bit about her my world has been enriched. And from the posts and condolences she did for many other people as well.

I can identify with this jumble of thoughts. My father told me on my 40th birthday (his 64th), "You have reached middle age, but never get old. Die young, no matter how old you are!". He also insisted that he was 30 until *I* turned 30....LOL....

He's now 75-odd (I lose track) and still travelling the world with my mother spending my inheritance having new experiences. I hope to God they can keep doing this for another 20 years and I inherit nothing!

R..

 

[freewillie]

. . ."It is also reasonable to expect diving could provoke an acute arrhythmia, which might result in sudden death. The arrhythmia is a more likely cause of death for older divers. . .

Diving exposes divers' bodies to various stressors that independently affect cardiovascular function. The major stressors are immersion, exposure to cold, increased partial pressure of oxygen and increased work of breathing. The combined effect of these factors is that the volume of blood in the vessels of the chest and heart increases significantly, stretching the walls of heart and large vessels. Pressure in the right atrium and blood pressure slightly increase — more so in cold water. The heart has to work harder to maintain circulation. These conditions contribute to various arrhythmias, from bradycardia (slow heart rate) caused by cold to tachyarrhythmia (racing heart rate) caused by cardiac and neuroendocrine responses to stress. Older people, especially those with structural cardiovascular changes and weaker function, are at greater risk of adverse reactions to these stresses.

As Carl Edmonds, M.D., describes and DAN® data confirm, "The victim often appeared calm just before his final collapse. Some were unusually tired or resting, having previously exerted themselves, or were being towed at the time — suggesting some degree of exhaustion. Some acted as if they did not feel well before their final collapse. Some complained of difficulty in breathing only a few seconds before the collapse, whereas others underwater signaled that they needed to buddy breathe, but rejected the offered regulator. Explanations for the dyspnea include psychogenic hyperventilation, autonomic-induced ventilatory stimulation and pulmonary edema — the latter being demonstrated at autopsy. In all cases there was an adequate air supply available, suggesting that their dyspnea was not related to equipment problems. Some victims lost consciousness without giving any signal to their buddy, whereas others requested help in a calm manner.". . .

(From DAN Article "Matters of the Heart")

All true. Keep in mind however that one does not simply suffer an arrhythmia in an otherwise normal heart. There are some congenital arrhythmias in younger patients but those are actually automatically disqualifying medical conditions to diving. It's safe to assume she did not have one of those types. The common types of arrhythmia that would lead to sudden loss of consciousness occur in patient with previous heart disease and almost always in the setting of a previous heart attack or similar cardiac conditions. And in that light all the other factors of cold, immersion, and physical exertion also lead to increased risk of cardiac complications in an older diver. Even if physically fit.

 

[boulderjohn]

. But later there was an article that his wife was suing the rebreather company. It seems that even for a diver with thousands of dives that a new activity also makes you a newbie for that one activity.

Just to clarify....

Wes was a very experienced rebreather diver. He was not, however, either experienced or trained on the brand/model he was using, and he did not take bailout bottles with him. I do not believe there wax any indication of a rebreather failure in that incident.

 

[Kevrumbo]

. . ."It is also reasonable to expect diving could provoke an acute arrhythmia, which might result in sudden death. The arrhythmia is a more likely cause of death for older divers. . .

Diving exposes divers' bodies to various stressors that independently affect cardiovascular function. The major stressors are immersion, exposure to cold, increased partial pressure of oxygen and increased work of breathing. The combined effect of these factors is that the volume of blood in the vessels of the chest and heart increases significantly, stretching the walls of heart and large vessels. Pressure in the right atrium and blood pressure slightly increase — more so in cold water. The heart has to work harder to maintain circulation. These conditions contribute to various arrhythmias, from bradycardia (slow heart rate) caused by cold to tachyarrhythmia (racing heart rate) caused by cardiac and neuroendocrine responses to stress. Older people, especially those with structural cardiovascular changes and weaker function, are at greater risk of adverse reactions to these stresses.

As Carl Edmonds, M.D., describes and DAN® data confirm, "The victim often appeared calm just before his final collapse. Some were unusually tired or resting, having previously exerted themselves, or were being towed at the time — suggesting some degree of exhaustion. Some acted as if they did not feel well before their final collapse. Some complained of difficulty in breathing only a few seconds before the collapse, whereas others underwater signaled that they needed to buddy breathe, but rejected the offered regulator. Explanations for the dyspnea include psychogenic hyperventilation, autonomic-induced ventilatory stimulation and pulmonary edema — the latter being demonstrated at autopsy. In all cases there was an adequate air supply available, suggesting that their dyspnea was not related to equipment problems. Some victims lost consciousness without giving any signal to their buddy, whereas others requested help in a calm manner.". . .

(From DAN Article "Matters of the Heart")

All true. Keep in mind however that one does not simply suffer an arrhythmia in an otherwise normal heart. There are some congenital arrhythmias in younger patients but those are actually automatically disqualifying medical conditions to diving. It's safe to assume she did not have one of those types. The common types of arrhythmia that would lead to sudden loss of consciousness occur in patient with previous heart disease and almost always in the setting of a previous heart attack or similar cardiac conditions. And in that light all the other factors of cold, immersion, and physical exertion also lead to increased risk of cardiac complications in an older diver. Even if physically fit.

There's also a history of recent Concussion/Brain injury, days before the dive:

Originally Posted by BDSC
Her [Lynne's] fall during riding was described as a "nasty" fall and it appears it happened just days before her dive. I was just wondering if she had gone to a doctor to have things checked out. Now I know she was a doctor but sometimes as the saying goes, "A doctor can be their own worst patient."

Possible co-morbid sequelae following history of recent brain injury which could cause cognitive impairment, vertigo -to loss of consciousness during dive:

• Postconcussion syndrome. Some people begin having postconcussion symptoms — such as headaches, dizziness and thinking difficulties — a few days after a concussion. Symptoms may continue for weeks to a few months after a concussion.
• Post-traumatic headaches. Some people experience headaches within a week to a few months after a brain injury.
• Post-traumatic vertigo. Some people experience a sense of spinning or dizziness for days, week or months after a brain injury.

And finally, just from the fighting the current & downcurrent:

CO2 retention leading to acute Hypercapnia at depth under extreme physical exertion:

Originally Posted by TSandM
Overbreathing the regulator MEANS a CO2 hit . . . It means the increased work of breathing of using a regulator is enough, at the current demand, to prevent you from exhausting all your CO2. All regulators can deliver more gas, faster than you can use up oxygen, but the small increase in resistance involved in trigger the inlet valve and opening the exhaust valve can make the difference between being able to keep your CO2 normal under heavy work loads, and not being able to keep up.

Panic in the experienced diver?

Originally Posted by TSandM
CO2 in the bloodstream is completely determined by minute ventilation, assuming the gas you are breathing does not contain additional CO2. Bailing to open circuit definitely makes it POSSIBLE to reduce the blood CO2 level, assuming you can achieve a higher minute ventilation than what's required to keep the CO2 where it is (which is in part related to level of exertion). It may not, however, be possible to reduce CO2 fast enough to clear your head and get rid of the panicky feeling, in part because the natural tendency when panicky is to breathe as fast as possible. On scuba, this means reducing the efficiency of the ventilation, because too much of it is just going to exchange gas in the trachea and large bronchi, which don't exchange gas. That's why we are taught in OW that, if we begin to "overbreathe our regulator" (meaning the diver feels short of breath despite breathing as much as he can), we are to STOP, hang onto something (reduce exertion) and breathe SLOWLY and DEEPLY. It is then possible to reduce CO2. What may not be possible is to stay rational long enough to do it.

Panic in the experienced diver?

CO2 Retention and Narcosis

. . . [Increased] Gas Density & Work-of-Breathing at depth; then throw in Physical Exertion or a Stress Condition, resulting in overbreathing the regulator --all leading to the Vicious Cycle of CO2 Retention and sudden Narcosis [aka "the Panicky Feeling" or "The Dark Narc"]. Can result in severe cognitive impairment at depth or worst case stupor and ultimately unconsciousness. . .

Taken from Undersea Biomedical Research, Vol 5, No. 4 December 1978 Hesser, Fagraeus, and Adolfson:

"Studies on the narcotic action of various gases have shown that the ratio of narcotic or anesthetic potency of CO2 and N20 approximates 4:1, and that of N2O and N2 30:1. From these figures it can be calculated that CO2 has at least 120 times the narcotic potency of nitrogen. Our data would suggest that the narcotic potency of CO2 is even greater, i.e., several hundred times as great as that of nitrogen."

Any of the medical conditions above alone or in concert together could have caused incapacitation and loss of consciousness at depth. . .

 

[freewillie]

I was unaware of the head injury. It actually brings into play the possibility of a seizure. I would tend to doubt post concussion syndrome since as a trained ER doctor Lynne should have recognized headache after a fall as a red flag warning. In the absence of a headache it makes it unlikely that she had a concussion or post concussion syndrome. It does make vertigo also higher on the differential list.

 

[Kevrumbo]

I was unaware of the head injury. It actually brings into play the possibility of a seizure. I would tend to doubt post concussion syndrome since as a trained ER doctor Lynne should have recognized headache after a fall as a red flag warning. In the absence of a headache it makes it unlikely that she had a concussion or post concussion syndrome. It does make vertigo also higher on the differential list.

Yes: Rule Out Seizure and Rule Out Post Traumatic Vertigo -current history of head injury. . .also add to the differential diagnoses list: Rule Out Alternobaric Vertigo -previous history of vertigo while diving.

 

[uncfnp]

There's also a history of recent Concussion/Brain injury, days before the dive:



Possible co-morbid sequelae following history of recent brain injury which could cause cognitive impairment, vertigo -to loss of consciousness during dive:

• Postconcussion syndrome. Some people begin having postconcussion symptoms — such as headaches, dizziness and thinking difficulties — a few days after a concussion. Symptoms may continue for weeks to a few months after a concussion.
• Post-traumatic headaches. Some people experience headaches within a week to a few months after a brain injury.
• Post-traumatic vertigo. Some people experience a sense of spinning or dizziness for days, week or months after a brain injury.

And finally, just from the fighting the current & downcurrent:

CO2 retention leading to acute Hypercapnia at depth under extreme physical exertion:



Any of the medical conditions above alone or in concert together could have caused incapacitation and loss of consciousness at depth. . .

Where does it say she had a concussion?

 

[AfterDark]

Where does it say she had a concussion?

If memory serves correctly she was thrown from a horse recently before the dive so the possibility is she may have had a concussion.

---------- Post added September 11th, 2015 at 09:16 AM ----------

All true. Keep in mind however that one does not simply suffer an arrhythmia in an otherwise normal heart. There are some congenital arrhythmias in younger patients but those are actually automatically disqualifying medical conditions to diving. It's safe to assume she did not have one of those types. The common types of arrhythmia that would lead to sudden loss of consciousness occur in patient with previous heart disease and almost always in the setting of a previous heart attack or similar cardiac conditions. And in that light all the other factors of cold, immersion, and physical exertion also lead to increased risk of cardiac complications in an older diver. Even if physically fit.

She was diving dry so unless her suit flooded the cold probably didn't have anything to do with anything.

 

[uncfnp]

If memory serves correctly she was thrown from a horse recently before the dive so the possibility is she may have had a concussion.

I don't know. Seems like a huge leap to go from a "nasty fall" to TBI/concussion, especially in a highly trained ER physician. And if indeed Lynne did have a head injury and elected to dive anyway, this goes against everything I know about Lynne and her cautious nature.

 

[AfterDark]

I don't know. Seems like a huge leap to go from a "nasty fall" to TBI/concussion, especially in a highly trained ER physician. And if indeed Lynne did have a head injury and elected to dive anyway, this goes against everything I know about Lynne and her cautious nature.

I don't need convincing I agree, just posting where I think it came from but, one never knows; even MDs are wrong sometimes. As we say we don't know what we don't know.

I was real surprised when I went to the Urologist thinking I had a UT infection and found prostate cancer, yep we don't know what we don't know.