Tag: nitrogen narcosis

I See Dead People – Sort Of

The exit to the Morrison Springs cave. (photo credit: ZoCrowes255)

The young man in a swimming suit was lying lifeless at the bottom of a fissure on the floor of Morrison Springs, a popular underwater cave in Walton County, Florida. If his eyes had been open, he would have been staring straight up at me. But mercifully, his eyes were shut, as in sleep.

My diving buddies from the Georgia Tech Aquajackets dive club and I were breathing air from scuba tanks at about 110 feet sea water. We were in a portion of the cave that received no indirect light from the cave opening. Without the cave lights in many of the diver’s hands there would have been total darkness.

Who knew that on my second so-called “open water” dive I would find myself deeper than 100 feet in a cave, using the dispersed light from my buddies’ dive lights to examine a very fresh looking corpse? He looked to be about our age, late teens, high school or college age. A rock outcropping hid his body from about mid-hip level down. But the top portion of a bathing suit, his lean stomach, chest, and boyish-looking face and head was plainly visible.

There must have been some current at the bottom of the crevice because his brown hair was waving gently, being the only sign of motion from the deathly pale white boy with closed eyes, waiting patiently to be recovered to the surface.

I and the other divers stretched our arms and shoulders as far into the crevice as we dared, reaching towards the young man, hoping we could grab onto some part of his body. But it was futile – he was at least a foot out of our reach. Finally, checking our dive watches, we saw it was time to swim toward the cave entrance and start our ascent.

Since there was no scuba gear on him he must have been a free-diver, a breath-hold diver who entered the cave then passed out and sank to the deepest, most inaccessible portion of the cave. As I and the other divers rose along the limestone borders of the cave I watched the darkness surround the young man’s cold body once again. I felt lonely, almost as if I could feel his spirit’s loneliness.

As I reached the surface I turned to the closest diver, removed my regulator from my mouth, and panted, “How are we going to recover that body?”

His response stunned me.

“What body? That was no body – that was a Navy 6-cell flashlight!

How could it be? I would have signed a sworn affidavit to the police describing everything I had seen, in detail, just as I’ve reported it to you many years later. The visual details, the textures, the emotions will not leave me.

But they were not real.

As for why that happened, the only thing I can assume is that for a nineteen-year old novice diver, descending in the dark to 110 feet, in a cave, might be just a bit more than the diver’s mind is prepared for. The nitrogen in air is narcotic if found in high enough concentration, so I was undoubtedly suffering from nitrogen narcosis. Plus, at the time the entrance to the Spring was macabre, with a large photo of a diver with his back filleted open by a boat propeller, and signs prominently displaying warnings of the large number of fatalities in the cave from poorly trained and equipped divers exceeding their limits.

My mind was prepared to witness tragedy, and the normally mild nitrogen narcosis of 110 feet may have  been just the trigger needed for a vivid hallucination.

I have had no hallucinations since then, from diving or anything else, except for one medical procedure reported on in this blog. But what remains remarkable to me was my absolute conviction that what I had seen in that cave was real. Consequently, I now know very well  that what people testify as being real, whether they are diving or not, may in fact be only imagined.

Diving with Hydrogen – It’s a Gas

When most people think of hydrogen, they think of the fuel that stars burn in their nuclear fires, the hydrogen bomb, or the Hindenburg disaster. Hydrogen is known for its combustibility and explosiveness. Not many people would think of diving underwater with it.

Technical divers breathe various gas blends, using mixtures of nitrogen, oxygen and even helium. But leave it to the ever inventive Swedes, makers of some of the best diving equipment in the world, to use hydrogen as an experimental diving gas as early as the 1940s.

Hydrogen will not burn under two conditions; if there is too little hydrogen, or too much hydrogen and not enough oxygen. A gas mixture (air or oxygen) with less than 4% hydrogen will not burn, and with more than 94% hydrogen in oxygen (or 75% hydrogen in air), the gas mixture will also not burn. So 100% hydrogen will not burn, unless it leaks out of its container and gets diluted in air. And then if there is an ignition source, woosh, a la Hindenburg.

 

A diver with supposed nitrogen narcosis. Photo credit, Daniel Kwok on flickr.

So why would anyone consider breathing hydrogen? When diving deeper than a few meters, you need a so-called diluent gas to mix with oxygen. Air is a mixture of nitrogen and oxygen, and when compressed, that nitrogen becomes narcotic, leading to nitrogen narcosis, or “rapture of the deep”. When air is compressed it also becomes dense, making it more difficult to breathe than air is at the surface.

Helium, often used by deep diving Navy and technical divers, is less dense than nitrogen and therefore is easier to breathe at depth. Furthermore, it is not narcotic, so no more “rapture of the deep”.

But for seriously deep diving, greater than about 450 msw (~1500 fsw), even a mixture of helium and oxygen becomes dense enough to impede breathing. One solution is to use an even lighter gas, hydrogen.

Experimental hydrogen-helium-oxygen gas mixtures have been used by COMEX in France to slightly exceed, at 2290 fsw (701 msw), the U.S. deep diving record (2250 fsw, 686 msw) set using a mixture of helium, nitrogen and oxygen.

Hydrogen has one annoying property — it is narcotic. It is far less narcotic than hyperbaric nitrogen, and some narcosis seems to be necessary to counteract the deleterious effects of the High Pressure Nervous Syndrome (HPNS). However, unlike nitrogen narcosis, which is akin to mild alcohol intoxication, hydrogen narcosis is reported to be psychotropic, inducing at great depth altered realities akin to those produced by LSD.

I once was conducting medical research on a 450 msw dive at the German GUSI deep diving chamber, and one of the divers was a French diver who had been a subject on the French hydrogen dives. He reported, without going into detail, that he did not like the effects of hydrogen at all. It was strange, he said. On the other hand, the same diver did very well on the helium-nitrogen-oxygen gas mixture used at GUSI and Duke University.

That some exotic gases on deep experimental dives would be considered strange is an understatement. Deep hydrogen has been reported to produce out of body experiences, something that a person as well grounded as a professional diver would consider frighteningly bizarre.

Swedish diver Arne Zetterström

The Swedes, and Arne Zetterström in particular, were interested in hydrogen diving during World War II for a simple reason; they wanted to dive deep, without the effects of nitrogen narcosis, but did not have access to helium. Most helium comes from gas wells in the United States and Russia. So, looking for another diluent gas other than helium, Zetterström briefly considered two constituents of intestinal gas (flatus), namely methane and hydrogen. Arguably, it was easy for the Swedes to produce plenty of methane and hydrogen. Just how they planned to do that is something I never asked.

Eventually, hydrogen was chosen for the Swedish dives simply because hydrogen was less dense than methane.

In principle, hydrogen could be used by a deep technical diver, but only at depths deeper than 132 fsw (5 atmospheres), a depth which would turn the noncombustible 4% oxygen in hydrogen gas mix into a so-called normoxic gas mixture, meaning it would have about as many oxygen molecules per breath as air at the surface. If the diver attempted to come shallower on that same gas mixture, he would lose consciousness due to hypoxia.

Since helium is not a combustible gas it does not have gas mixture restrictions. As long as  a helium-oxygen gas mixture contains the right amount of oxygen (not too much and not too little), then it will be safe. Both nitrogen and helium are therefore far preferred over either of the flammable gases methane and hydrogen  for use in breathing gas mixtures for diving.

Nevertheless, as divers continue to explore ways of diving deeper, it is certainly possible that hydrogen and other exotic gases may eventually play a role in deep life-support. Who knows, perhaps a perfect gas mixture will involve a blend of hydrogen and methane along with oxygen. If so, perhaps we could call it, oh I don’t know, maybe … Flatogen!

 

 

 

 

 

Those Doctors Are Trying to Kill Me!

Be careful what you say before going under anesthesia.

I had reached the age when my internist required me to get a colonoscopy, and I was not looking forward to it. I got gowned up in one of ridiculous back open gowns, for obvious reasons, but had a darkly funny thought when the nurse attached an I.D. bracelet to my wrist. I joked to the nurse, and to my wife, about the bracelet saying DNR, “Do Not Resuscitate.” Haha. See how I make joke when I nervous?

I know, I should have known better than to joke about a DNR, because it is after all a serious, and usually anguish-filled end-of-life decision someone has to make, at some point. It really wasn’t suitable for a joke, But hey, I can kid about my own mortality any time I want. Right?

Well, the joke was on me, because my timing for the joke was really bad. A couple of minutes later I was given an intravenous cocktail of Versed, propofol, and fentanyl. I was out.

In medical parlance, that form of anesthesia is called a MAC – Monitored Anesthesia Care. Which, for me, meant I didn’t care, or know anything at all, for a few minutes.

But when I woke up, things had changed. While I was unconscious, having my body invaded, someone had placed a DNR band on my wrist. And I was not happy about that, not at all. Who gave them permission?

I voiced my complaint to the nurse and my wife who were helping me get off the gurney and walk me to the car. But they didn’t seem to care! They wouldn’t even look at that blasted wrist band. Why was my wife so uncaring about my obvious distress?

At one point as my wife was driving me home, she started laughing at me. Of all the nerve! All I did was try to tell her about the DNR wrist bracelet. And she thought it was funny!

But I still remember my comeback to her. “Laugh jackass, laugh!”

Boy, I sure had her number! That shut her up; until she started tucking me in bed for a nap.

But I didn’t want to sleep. I was mad as Hades! Did you know, someone had put a DNR bracelet on me while I was unconscious?

And then something clicked in her, born of years of raising toddlers and preschoolers. As I was trying to climb out of the bed she held my shoulders down, put her face right in front of mine, and said forcefully,

“No. It does not say that! Now go to sleep.”

She later said I got a very hurt look on my face. And then I laid back, and was out, again.

When I woke up, all was right with the world.

But while I was sleeping that darned DNR wrist band had been cut off my wrist and the evidence destroyed. My wife still claims no knowledge of it.

If I may opine about what happened to me: I believe this is an example of idea fixation brought on by anesthetic agents. It was as if, on induction, a particular mental state was captured, which was in fact a mixture of dark humor regarding my bracelet, which obviously was not a DNR bracelet, and some anxiety over the procedure. Perhaps those anesthetic agents caused the emotional content to morph into something of its own creation, some paranoid delusion which was not abolished until the last vestiges of the drug were eliminated.

If you look up the term “idea fixation” you’ll see, oddly enough, repeated mention of nitrogen narcosis, a diving induced mental state of which I am all too aware. From a scientific perspective, there are qualitative parallels between the narcosis of nitrogen and the narcosis of certain anesthetic agents.  But I don’t know how many events such as the one I experienced have been recorded in the medical literature. If you know, please share with me.

In the meantime, I plan to maintain a tight grip on even the most humorous impulses I might have before undergoing anymore medical procedures requiring sedation. The next time, my wife may not be so understanding.