Seizures, broken spines and vomiting: Scientific testing that helped facilitate D-Day

Transcript

TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. How can the human body survive the extremes of the deep sea, whether it's deep-sea divers or people within the enclosed environment of a submarine, whether it's civilians or special operations forces? How do blasts and bombs underwater affect the body compared to the impact of blasts on land? These are some of the questions my guest, Rachel Lance, has researched for the military and at Duke University. This is her last semester at Duke. She's a biomedical engineer and blast injury specialist. For several years, she was an engineer for the U.S. Navy, researching and testing new underwater technology for Navy divers, SEALs, and Marine Force Recon personnel.

She currently conducts research at Duke University using their hyperbaric chamber. It's an enclosed chamber in which the air pressure can be increased or decreased, along with the levels of oxygen and other gases, to simulate the extremes of underwater environments, monitor the negative impact on the body and test solutions. Her new book, "Chamber Divers," is about the research conducted by obsessive scientists before and during World War II which proved essential to the success of D-Day, when allies had to conduct surveillance, searching for traps and mines underwater and on the beach before storming the beach of Normandy on D-Day. In order to do the research, the scientists put themselves through extremes in the hyperbaric chamber and sustained some pretty serious injuries.

Rachel Lance, welcome to FRESH AIR. What were you researching that made you interested in the World War II underwater research?

RACHEL LANCE: I read this paper about carbon dioxide. And it wasn't extremely exciting. It concluded essentially that carbon dioxide is bad for you, and it hurts, which I already knew. But something about the date bothered me. It was published in 1941, which was obviously wartime, and it was published by a group of British scientists. In scientific research, the paper usually comes out about a year after the research was done. So that meant that these people were working on this question of carbon dioxide in 1940 in London. The other thing that was happening at that time period was the blitz. So something about carbon dioxide was so critical to them that they were looking at it while they were being bombed. From there, I just kept pulling at the thread until the entire story became evident of what they were actually working on.

GROSS: So tell us more about what they were actually working on.

LANCE: They started out looking at submarine survival. So this - the Allied militaries had built all these submarines in preparation for World War II, because they essentially knew some sort of conflict was coming. But in the summer of 1939, three of them went down in rapid succession. There is the USS Squalus, the HMS Thetis and the French Phenix, which still remains lost. However, when these submarines sink, the Allies realized that they didn't know very much about surviving inside them, escaping them, or even what to do if one of these accidents occurred. So this research group that I was following, which was based out of University College London, UCL, and led by a scientist named J.B.S. Haldane, were looking at these problems of undersea survival, of how people breathe inside enclosed spaces, and how people need to treat these breathing gases if they want to stay in these enclosed spaces on purpose. Eventually, that transitioned into diving and diving technologies, and all of those things together were used to scout the beaches of Normandy and facilitate the landings of D-Day.

GROSS: So in order to do the research, the scientists conducted research on their own bodies in hyperbaric chambers. I give a very cursory description of a hyperbaric chamber. You've been in one at Duke. They have a state-of-the-art hyperbaric chamber. Tell us more about the chamber and what it's like to be inside of it.

LANCE: It's loud (laughter).

GROSS: It's loud?

LANCE: A hyperbaric - yeah, it's loud.

GROSS: Yeah. I would think there's, like, no sound, you know...

LANCE: That's my strongest impression.

GROSS: Yeah.

LANCE: The opposite - the hyperbaric chamber is essentially a gas pressure vessel. So you're basically inside a scuba tank. Now, our scuba tanks at Duke are very fancy. We have seven of them all connected together. So it is like being inside of a little hamster tube village. And ours can go to either high pressure or low pressure. But in that process, you have tons of air and gases moving through the piping. So that's my biggest impression is you're in this enclosed space. They're always either circular, spherical or cylindrical because that's a stronger shape. And then you constantly have noises. You constantly have gas flow as you're pressurizing. It gets really hot really quickly. As you ascend the other direction, it gets really cold really quickly. And then you have people on the outside who are monitoring the gas composition in there when you're in an enclosed space to make sure you're breathing safe levels. So yes, the biggest sensory takeaway from a hyperbaric chamber, for me, is probably the noise.

GROSS: So one of the things that happens in the hyperbaric chamber is that you can increase or decrease the pressure. So when you're underwater, is all of the increased pressure from the weight of the water?

LANCE: Pretty much. We have one atmosphere that we breathe. That atmosphere of gas we forget about pretty often, but it does sit on top of us all the time. Once we go under the water, we have additional atmospheres that essentially get piled on. So every 33 feet, or 10 meters if you're metric, is equal to another atmosphere of pressure. The deeper we go, the more the pressure increases simply from the weight of that water pushing down.

GROSS: And that's really dangerous to the body, as the researchers found out. What does it do to the body to have that much pressure on top of you? And the real problem comes in if you emerge from the depths too quickly, you get what's known as the bends. Like, why does that happen?

LANCE: That's the million-dollar question, isn't it? Basically, the human lungs are very weak. They're not a strong organ. And so they're really good at what they do in terms of processing gas, but they do it passively. So they essentially just let that gas flow come in and out of the body. What that means for breathing is that when we breathe a gas, we have to breathe gas of the approximately same pressure as the air around us or the water around us. When you're underwater, that means you're breathing high-pressure gas. That means that that increased pressure can help those gases absorb into your bodily tissues.

The air around us is about 78 to 79% nitrogen. So as we're underwater and we're breathing that higher pressurized gas, that nitrogen and the other gases absorb into our tissues. What you described with decompression sickness, the bends, that's when we come back up, we go to those reduced pressures too quickly, the nitrogen comes out instead of harmlessly in the bloodstream, processed by the lungs, it comes out as bubbles. That's really bad. It causes all kinds of physiological issues.

GROSS: Oh, so you get bubbles in your lungs and bubbles in your blood?

LANCE: In the most extreme manifestations, you can get bubbles everywhere. There are case reports of bubbles in the brain, bubbles in the spinal cord, bubbles in the liver and in the joints. Those are the extreme cases. One of the really interesting mysteries about decompression sickness is that we don't actually know where the bubbles originate from. Bubbles in the bloodstream are not related to the actual symptoms of the disease itself. So you can have a person in extreme pain with very low levels of bubbles in their bloodstream, and you can have people with lots of bubbles in their bloodstream who have no pain and no other signs of issues. So one of the things that I research at Duke and in hyperbarics in general is trying to figure out where these bubbles are coming from in the first place.

GROSS: How do you find out?

LANCE: Sometimes it feels like magic. Anytime you're looking at the human body, how do you find out is the key problem. You have to be creative with instrumentation, with imaging, with testing, with looking at indirect metrics so that you can try and trace these mysteries and these sources of injury back to their origin without doing further damage to the person you're studying. A lot of what I do at Duke involves the creation and the development of new products and new methods that work under pressure and work at depth, because when we're in that extreme, isolated scenario, in this incredibly thick metal container, we don't have access to most of the tools as the rest of the hospital.

GROSS: You know, I'm thinking of the scientists during World War II who exposed themselves to extreme pressure in the hyperbaric chamber, and some of them got really sick. They basically had the equivalent of the bends, had decompression illness. You're not going to do that to yourself, and you're not going to recruit human subjects to get really sick. So what kind of body can you study?

LANCE: We try to flirt with the line of danger but never cross it. That's a big rule that complicates the study of injury biomechanics in general. And that's something that I encounter a lot with blast trauma. There is a gentleman in this book in "Chamber Divers" named Horace Cameron Wright, and he encountered that same issue. He wanted to look at underwater explosives. Well, he didn't feel ethically comfortable putting other people down and risking them get injured, so he decided to go himself. When we're looking at these problems, we have that same ethical conundrum. We can't intentionally injure someone. We can only take advantage of cases where people have injured themselves. And so those cases are very valuable. Whenever people have an accident in the real world, that's a big part of data collection. That's a big part of what I study.

And then when we're in a controlled environment, we try to use what we do know in order to subject people to perhaps more than what we consider to be totally safe, but stop short of what is dangerous with the knowledge that we're literally in the exact right facility to treat them if something bad does happen. That was true with the chamber divers, as well. When they got decompression sickness, when they had major problems, they were already in the chamber, which is also the exact right way to treat these problems. And so it was better for them to experience it than for the World War II military personnel to get it out in the field.

GROSS: You just mentioned if you get the bends from experiments in the hyperbaric chamber, the hyperbaric chamber is the best place to be to cure the bends. And is that because the pressure can keep gradually being adjusted, just as divers have to do, which is to slowly emerge and stop occasionally in the water so that they don't suddenly change the pressure?

LANCE: Yes. That's exactly right. So if someone comes up and they start to show signs or symptoms of decompression sickness, they can be recompressed in a hyperbaric chamber. Now we're increasing that pressure around them back to a higher level. And the theory is that shrinks the bubbles in their bodies back down so that we can bring them up more slowly at a safer, more prolonged rate and let the nitrogen come out in a harmless fashion.

GROSS: So what are some of the extremes that the World War II researchers exposed themselves to in the hyperbaric chamber? What experiments did they conduct on themselves?

LANCE: Oh, my gosh, they put themselves in there for things that would not be legal today. If I tried to do that, even if I had subjects who consented, I would possibly be criminally prosecuted. They were putting themselves in there and breathing pure oxygen and rocketing the chamber down as quickly as they go to see if they could kind of outrun the negative effects. They were taking some of these gases, like oxygen, down to depths that we now know are extremely dangerous and toxic. And they were continuing to do this even after they were having severe injuries. With modern research, we have what are called serious adverse event reporting requirements. So if something bad happens in our research, we have to sit down and have a conversation about the ethics of asking people to continue.

Whereas this group, because their goal was to prevent military deaths during the invasion of Normandy, they figured better we do it here in the lab. And so they just kept exposing themselves to this over and over, especially these high-oxygen pressures. They were having seizures. They were breaking spines. Two of them broke their spines. They were dislocating their jaws. One of them, Helen Spurway, dislocated her jaw five times in the same dive, and they kept going. These are things that would be wildly unethical and illegal today. And they were doing it because they were in this context of the Blitz and the bombings and the horrors of World War II happening around them.

GROSS: Let me reintroduce you here.

My guest is Rachel Lance. Her new book is called "Chamber Divers: The Untold Story Of The D-Day Scientists Who Changed Special Operations Forever." We'll be right back. This is FRESH AIR.

(SOUNDBITE OF FLORATONE'S "FRONTIERS")

GROSS: This is FRESH AIR. Let's get back to my interview with Rachel Lance. She's a blast injury specialist who conducts research into how the human body can survive in the extreme environment of the deep sea. Her new book is about a related subject. It's about the World War II scientists who conducted research about the extremes of underwater. And this research was critical to the success of D-Day, when Allied forces stormed the beach of Normandy.

You know, one thing - one of the many things I found really fascinating in the book was that in the early 1900s, when the Brooklyn Bridge was being constructed, the people there, the men who were working underwater, doing the underwater part of the bridge, they got the bends before anybody knew what the bends were.

LANCE: Right.

GROSS: And so you had all these men getting, like, super sick or dying, and nobody understood why.

LANCE: Nobody knew. And this is classic with the world of injuries and extreme environments. You don't know what's going to be a problem until somebody goes first. And that's true with so much of science, with so much of testing and the amount of research that we do. People have been talking about artificial kidney and kidney transplant from a pig and the ethics of that. And the brutal reality is you can do benchtop testing until you die, but nobody really knows what will happen in a human body until, like the Brooklyn Bridge, someone just goes first. And so those unfortunate caisson workers, yeah, they were the first ones who were really experiencing decompression sickness and experiencing how brutal and lethal that can be.

GROSS: Was the cause of their sickness discovered in time to save other men from dying?

LANCE: Not as far as I'm aware for the bridge. They sort of just powered through. They were having all these deaths, and they just hired more workers, which is perhaps why a lot of the workers there started quitting toward the end of the project. But after that, it was used by the scientific and research community as an example of a thing to stop. This is kind of why a lot of us, myself included, get into science. When we see things happening, we have the drive to explore them, understand what's happening and then try and prevent the next case from going on. So the - Haldane saw these cases - J.B.S., Haldane's father, saw these cases and then used that to start researching diving in a more controlled way. So now decompression sickness is extremely preventable.

GROSS: You know, I don't think I'll ever drive across the Brooklyn Bridge again without thinking about this story.

LANCE: I hope not.

GROSS: (Laughter) Yeah.

LANCE: Somewhere down there - yeah, somewhere down there are wooden caisson shells in which people worked until they literally died. And I think that's incredibly powerful in terms of remembering the context of where our society comes from and how it's been built.

GROSS: Something I'd really like to have you explain - and you explain why too much oxygen can be deadly...

LANCE: Correct.

GROSS: ...When you're breathing.

LANCE: Did you know fresh air becomes poisonous deeper than about 200 feet?

GROSS: Wait, repeat that. Fresh air becomes poisonous...

LANCE: (Laughter).

GROSS: ...Below 200 feet?

LANCE: Right. Air is roughly 21% oxygen. So since oxygen can become toxic when you elevate the pressure, the 21% oxygen becomes toxic if you're diving deeper than about 200 feet below the surface of the ocean.

GROSS: So what is it about the oxygen that can become toxic - or even deadly - if there's the wrong proportion of it and there's too much of it?

LANCE: Our bodies use oxygen because it's extremely chemically reactive. Oxygen is one of these weird molecules that sits on the periodic table in a location that just makes it react with everything. We take advantage of this to build fires. That's why oxygen is needed for fires. We take advantage of this to design explosives. That's how we design explosives. And our body internally produces energy using oxygen in pathways that are not terribly dissimilar.

So what happens when you have too much oxygen is essentially that volatility turns against us. It can start to act on your lungs. It can start to kill the cells of your lungs. It definitely starts to act on your nervous system. So once you get beyond a certain pressure and concentration of oxygen, your nervous system can no longer defend itself against this essentially onslaught of reactivity. And you begin to have these really intense symptoms that if you don't remove the oxygen levels will eventually kill you.

GROSS: What kind of symptoms?

LANCE: It starts with minor muscle twitches. So people might have small twitches in their fingers or in their arms. One of the common ones is the upper lip. You kind of get a little Elvis thing going on.

GROSS: (Laughter).

LANCE: People start to have visual disturbances. The eyes use a ton of oxygen, and so they're one of the more sensitive measurements that we can have to when our breathing gas levels are going awry. So people start to hallucinate bright flashes or have twitches of their eye to the left and right. Eventually, it's going to escalate to seizures. And then from there, if the oxygen levels are not removed, then you'll have death.

GROSS: This is a little bit of a sidebar, but you talk about it in the book, and I think everyone will want to know this 'cause a lot of people buy antioxidants as a, you know, kind of vitamin supplement. And they're widely advertised. So how does that relate to what you're telling us about oxygen, if at all?

LANCE: Antioxidants are chemicals that react with oxygen and sort of neutralize it. So when we eat them in food, the theory is that the antioxidants we're consuming will react with the oxygen that's sort of extra in our bloodstream and neutralize it from having some of the more negative effects that can accumulate over time, like aging. Oxygen is thought to be the reason that we age. The problem is dosage.

So the antioxidants in food - I actually - it took me a lot of work to do this math. But I calculated the concentration levels of antioxidants in the most popularly cited, antioxidant-based foods, and they don't have the sufficient concentration to really make a difference. I did the math for while they were at pressure, and I don't remember the exact number off the top of my head. But it was something like 180 bottles of Merlot per breath that the diver would have to drink in order for the antioxidants to have an actual effect in neutralizing the oxygen. Don't get me wrong - I'm going to eat dark chocolate and blueberries forever, hopefully. But I'm not convinced that there's enough of the chemical substance in them to actually make a difference.

GROSS: If you're just joining us, my guest is Rachel Lance. Her new book is called "Chamber Divers: The Untold Story Of The D-Day Scientists Who Changed Special Operations Forever." And it relates to her own research on the extremes of being underwater, either in a submarine or as a deep-sea diver. She's done a lot of research for the military on this subject. We'll be right back after a short break. I'm Terry Gross, and this is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. I'm Terry Gross. Let's get back to my interview with Rachel Lance. She's a blast-injury specialist who conducts research into how the human body can survive in the extreme environment of the deep sea. She currently works as a scientific researcher on military diving projects at Duke University. This is her last semester at Duke.

For several years, she was an engineer for the Navy, researching and testing equipment to protect Navy divers. Her new book, "Chamber Divers," is about a group of obsessive civilian scientists who conducted research during World War II which proved essential to the success of D-Day. Their findings enabled the allies to conduct surveillance before D-Day, searching for traps underwater and on the beach before storming the Normandy beach. In order to do the research, the scientists put themselves through extremes in a hyperbaric chamber and sustained some pretty serious injuries.

A hyperbaric chamber is an enclosed chamber in which the air pressure can be increased or decreased, along with the levels of oxygen and other gases, to simulate the extremes of underwater environments, monitor the negative impact on the body and test solutions.

Let's talk about blast injuries in water - deep-sea water - versus on land 'cause you are a blast-injury specialist. What are some of the differences in terms of their impact on the body?

LANCE: There are two major differences. The first is that we don't have to worry about some of the things that we do on land, such as shrapnel and burns, because the density of the water slows down a lot of those effects before they can reach more than a meter or two.

The other big difference is that we have to worry a lot more about the shock wave. In air, the shock wave decreases very quickly. But in water, just like sound, it travels a lot more readily. And so imagine how far away you can hear whale sounds. You can hear whale sounds for miles and miles. The same type of impact where the density of water moves these waveforms along more efficiently than in air occurs with the shock wave from explosions. So you see different injury patterns from the underwater explosives, but most of them tend to be internal, which is kind of terrifying.

GROSS: Why are they internal and not - oh, 'cause there's no object that's piercing the skin. It's just the...

LANCE: Exactly.

GROSS: ...Blast waves. So...

LANCE: It's just the physics of the shock wave.

GROSS: So the shock waves, like, push into you and injure you internally. Is that what's happening?

LANCE: It's more that they travel straight through you. It's even more sci-fi than just a standard impact. So they don't carry with them a lot of force. So the actual force from a shock wave is not very strong. But what happens is you go from zero pressure - or whatever ambient pressure you're at - to the highest level of the shock wave, and it happens in zero seconds.

The metaphor I like to use is a car. Imagine you're in a car. You're at a full stop. And then all of a sudden, you're going 60 miles an hour with zero acceleration. This doesn't sound very pleasant. The same risk of injury occurs because of that sudden impact and that sudden infinite rate of pressure increase with the shock wave.

So as the wave is traveling through you, it can actually travel through most of the body fairly easily, like the arms and the legs. Below a certain threshold, it'll just pass through them without a lot of harm. But the lungs and any other gas-containing organs have that air. Again, we talked about how sound travels more easily underwater. Now it's hitting air. So at the surface of those air pockets, you have an effect called spalling, which is essentially where the shock wave is forced to slow down. And you get this spray of blood that goes into those gas pockets.

GROSS: I wonder how it feels.

LANCE: (Laughter).

GROSS: We usually, like, look for a bruise or a wound or - you know...

LANCE: Right.

GROSS: ...And there's nothing to see, I suppose, unless maybe there are bruise marks.

LANCE: That's part of what happened at the start of World War II. A lot of people were in the water because there's so much naval combat happening. There were U-boats terrorizing the Atlantic. And these ships would go down - including, like, the USS Midway and the USS Yorktown - would go down. And they would have their sailors waiting in the water. And then either a depth charge would go off or the U-boat would set off a torpedo, and that shock wave would travel and hit the sailors. Then all of a sudden, you've got sailors in the water with massive internal bleeding and no external signs of injury.

So this was a huge mystery at the start of the war that had been really understudied, and the physicians and the scientists were kind of scrambling. It was the same thing as trying to survive underwater. They - and in the submarines, they were hit by all of this new technology. They didn't know what was going on, and they had to study it all at once.

GROSS: How did they study it?

LANCE: They basically looked at what we look at today, which is people who have already been hurt through circumstances other than intentional introduction. But then because the war became so severe, that's when you start to see people experimenting on themselves. So that's when you start to see the chamber divers getting in their tubes, and you start to see Horace Cameron Wright climbing into the lake, along with dozens of volunteers to blast themselves.

GROSS: Right, exposing themselves to the shock waves of TNT underwater.

LANCE: Exactly.

GROSS: What about...

LANCE: When Horace Cameron...

GROSS: Yeah.

LANCE: ...Wright climbed out of the water after each explosion, he would use a stethoscope to measure where in his own lungs there were - there was blood.

GROSS: Huh.

LANCE: (Laughter) The lungs can handle a surprising amount of injury. Long term, I'm not sure how he survived himself, but the lungs can handle up to 15% injury or so without having severe symptoms. Like, if you try and sprint, you'll probably have an issue. But you can have low-grade levels of damage to your lungs and still be OK. So I think he just took some (laughter) days off and then tried again, to be honest.

GROSS: I think we need to take another break here. So let me reintroduce you. If you're just joining us, my guest is Rachel Lance. Her new book is called "Chamber Divers: The Untold Story Of The D-Day Scientists Who Changed Special Operations Forever." We'll be right back. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. Let's get back to my interview with Rachel Lance. She's a blast injury specialist who conducts research into how the human body can survive in the extreme environment of the deep sea. She's worked for the military and has conducted research at Duke University. She has a new book about the World War II scientists who did research related to the survival of the human body when exposed to the extremes of the deep sea. And this research was critical to the success of D-Day, when the Allies stormed the beach at Normandy and had to conduct underwater surveillance.

So what are some of the solutions that the World War II scientists came up with to help the military conduct underwater surveillance during World War II just before D-Day, so that - and this was critical to the success of D-Day?

LANCE: One of the big things that these scientists contributed was the improvement of their ability to use not only regular-sized submarines, but miniature submarines. These tiny subs had a smaller gas volume, which made the rules of breathing physiology even more time critical. And the scientists who were conducting these experiments on themselves were really the ones responsible for determining how much people could tolerate carbon dioxide buildup in there, how much chemical scrubber material they needed to bring with them in order to remove carbon dioxide to fulfill their missions, and how much oxygen they also needed to carry, as well.

So when we have the development of these mini subs called X-craft, they were then used by the British to start scouting the beaches of Normandy, because the tiny submarines, which were only about 10 feet tall, could get so much closer, and they could dive down to the bottom and wait offshore for night to come back around again. So using the work by these scientists, they had the subs full of carbon dioxide scrubber. They knew what their safe limits are. They knew what to do with the oxygen levels, and they would go over to Normandy in advance of D-Day and sink down to the bottom during the day, breathe inside their safe, enclosed environment and then come up at night, crawl ashore, measure the sand, measure the beach angles, provide detailed maps, everything, and then go home.

A lot of that credit can be due to this research lab at UCL, who, again, did this experiment by just putting themselves in a tank, closing the door and waiting to see how long they could physically handle the amount of carbon dioxide in there before they ended up with migraines and projectile vomiting. Great experimental endpoint.

GROSS: There's something called hyperbaric medicine. And we talked about what a hyperbaric chamber is and how it's used for research to simulate the environment of the deep sea so that researchers can understand what happens when the human body is exposed to the extremes of the deep sea. But there's something called hyperbaric medicine. How is that used? Like, outside of the World War II researchers who became ill because they exposed themselves to those extremes, how is hyperbaric medicine used?

LANCE: Hyperbaric medicine is a field that has both amazing effects and amazing controversy at the same time. It has proved to be really excellent for disease states where the issue is not enough oxygen. If you think about it, that makes sense. You pressurize the patients, you give them oxygen, you're forcing more oxygen into their bodies. So some of the cases that it's extremely helpful for are things like diabetic wounds. So these wounds become ulcers. They have a difficult time healing because diabetic patients tend to have poor circulation in their limbs. With hyperbaric treatment, they get the oxygen they need at that site to help those heal. The same thing is really useful for cancer patients who have radiation burns. If their immune systems are compromised by chemotherapy or simply just the trauma of the long, invasive cancer treatment, the radiation burns show a lot of responsiveness to hyperbaric compression because it forces oxygen to that wound site and allows them to heal.

There's also some controversy about hyperbaric medicine because since it tends to be pretty harmless, like, if you're pressurizing people under a known medical treatment table, there really aren't negative, long-term side effects to be spoken of. It sometimes then tends to get used by charlatans. So it's been used to treat both autism and chronic traumatic brain injury, both of which have huge bodies of evidence showing that it does not help.

GROSS: Early in your career, maybe even before you had a career, you watched hyperbaric medicine save a father's life. Can you tell us that story?

LANCE: Yes. That was when I was living out on Catalina Island, and that was my first hyperbaric chamber. Little baby Rachel. And I was out there as a volunteer. That's a completely volunteer-run chamber. So, yeah, I'm actually happy to give that a shout-out because they do run on donations. But I was out there volunteering to treat diving accidents, and we had a diver that came to us because he had either accidentally or something happened during the ascent, but he had an air embolism, which is what happens when you don't exhale properly and the air expands as you go up and it can rupture your lungs and travel into your body. A lot of the times, these can be fatal if they're not properly treated, and quickly, they can have very serious negative consequences.

And this gentleman was a man who had experienced an air embolism. He was brought to our chamber and we repressurized him. And once he got under pressure, he just kind of woke up. He had gone in blue, and I'm not exaggerating. This was not a human skin color. And I will always remember how he looked. It was this deep bluish purple. And he went in and the bubble shrank under pressure, and he returned to normal. And by the time he left, he was not only walking and talking, but perhaps more importantly, breathing in with a heartbeat.

GROSS: Most of your research has been about the human body in a deep-sea environment, whether in a submarine or just exposed in the water with - obviously with a suit on and a tank and all of that. But you've also done some research about outer space. Can you talk about some of the similarities and some of the differences between what you have to face as a researcher when you're looking at space versus sea?

LANCE: The most important similarity is the difficulty of the environment, not just on the human body, but on any instrumentation you want to bring in when you're doing research. So the biggest obstacle with both of these worlds is the engineering of products and devices in order to measure the things we even want to ask the questions about. So working in the hyperbaric chamber, the limitations on what I'm doing and what I'm building, it works for both environments. And that's why working with the Navy, we collaborated frequently with NASA. We were talking frequently with people building the high-altitude breathing systems for jets, things like that. And that's why in "Chamber Divers," I even included the story of a high-altitude research pioneer named Randy Lovelace. He built a breathing system and tested it on himself by kind of stealing a plane a little bit and jumping out of it, obviously.

So there's huge overlap here in the hostility of the environments that we're working in and in the fact that the body is undergoing pressure differentials. So high-altitude fighter pilots and astronauts all have to worry about decompression sickness because they're going from a higher pressure to a lower pressure. So our research has huge overlap there. They have to worry about their breathing systems. They have to worry about their carbon dioxide levels in the spaceship, which is now an enclosed environment, a lot like a hyperbaric chamber. And we actually hold our conferences together a lot of the times because the two environments, while wildly dissimilar in the pressures that we're facing, are united in the challenges.

GROSS: When you're doing research for the military, do you think about the lives that your research might be saving and the kind of mass casualties of the past that might happen again in the future? I mean, how focused are you on just, like, analyzing the data and, you know, dealing with the research at hand, and how much are you thinking about, like, the larger consequences of - you know, of the kind of situations where your technology might be used or, you know, the results of your tests might be used.

LANCE: Constantly. It's a constant concern for me. When I worked for the Navy, which was just short of nine years - I'll use this, an example. The government is not known for its lack of bureaucracy. So working for the government had this incredibly unique experience where I was in this big bureaucracy, and I would have to write memos for things that seemed ridiculous to me to justify. Like, oh, why do you need stainless steel? It's more expensive. Well, if I don't buy that, it'll rust away in two days. Things like that...

GROSS: It's underwater. Right.

LANCE: It's underwater.

GROSS: Yeah.

LANCE: It's going rust. Exactly. So things like that were a regular obstacle there. And the reason that I love that job and engage with that job so well, to the point that I wanted to keep researching for this community even after I left the Navy, was because I was able to interact with military personnel, and I was able to see how much they wanted this so that it could improve their chances of coming home safely. I don't work on weapons systems. I work on safety standards and safety equipment. And I'm motivated by that daily.

GROSS: Well, thank you so much. This was so interesting. It's a pleasure having you on the show. Thank you so much.

LANCE: Thank you so much for having me.

GROSS: Rachel Lance is the author of the new book "Chamber Divers." After we take a short break, TV critic David Bianculli will review the new miniseries "Franklin," starring Michael Douglas as Ben Franklin. This is FRESH AIR.

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