Deconstructing Decompression Sickness
By Eric Douglas and Jenn Loder
One woman's firsthand account of DCS, with commentary from the DCS experts at the
Divers Alert Network.
No one likes to admit they're bent. It means they've done something wrong. Errors in
judgment and planning mistakes can lead to decompression sickness (DCS), but more
often than not, it's a seemingly random event--the same dive profile you've done 10 times
can lead to problems on the 11th, and you may never know why. What follows is the
account of one woman, Jenn Loder, who suffered a DCS hit while on vacation in the Turks
and Caicos. I'll pause her story periodically so my colleagues at the Divers Alert Network
and I can shed some light on her experiences.
DCS briefly crossed my mind when my left shoulder
started to ache at the end of my third day of diving,
but I quickly dismissed it, thinking my overactive
imagination was getting the better of me. After all,
I was diving conservatively; I stayed well within
my no-decompression limits, did my safety stops
and ascended slowly. I chalked up the ache to
bumping my shoulder or straining a muscle and
headed for bed.
This is a classic case of denial. Divers often look
for and find other reasons to explain the pain,
numbness and tingling they're feeling, and though
Jenn felt concerned enough to check her rescue
manual, she looked for reasons why it couldn't
be DCS rather than acting on the reasons that
it could. In 14 percent of cases reviewed by Divers Alert Network, divers reported
experiencing symptoms before their last dive, meaning they noticed something was wrong
and still went back into the water, adding more nitrogen to their bodies and potentially
making the situation much worse. "Divers don't call DAN because they have symptoms,"
says Joel Dovenbarger, vice president of DAN Medical Services. "They call us because the
symptoms they have won't go away."
The next morning, thoughts of colorful reef fish, graceful rays and walls dropping off into
forever filled my mind. I couldn't wait to get back on the boat and out on the reefs. But wait.
That nagging ache in my shoulder was still there. Again, those pesky fears of DCS crept
into my thoughts. I even went and checked my rescue diver manual to look for other likely
symptoms: fatigue, chest pain, tingling. Nope, nope, nope. Again, I pushed the thoughts of
DCS aside. I figured it couldn't be possible ... after all, I was a twenty-something in pretty
good shape who didn't drink much or smoke at all–– what were the chances?
As the problem got significantly worse, Jenn made the right decision in recognizing the
severity of the situation and informing the dive staff--before she got in the water. Dive crews
are often the first responders in these cases, and though they're not medical professionals,
they do have working knowledge of the symptoms. It's important to remember that there is
no guaranteed diagnosis for decompression sickness--not even a doctor can give a 100-
percent diagnosis--because the symptoms aren't always obvious. They can be confused
with other injuries or medical conditions and easily written off as unrelated to diving.
The following are some of the most common symptoms reported to DAN, and the first three
are by far the most common.
within a few hours) is about as clear-cut as it gets. If you feel unusual--divers often describe
DCS symptoms as "something I've never felt before"--you're better safe than sorry. This
"unusual sensation" phenomenon is most true when it comes to pain, as the pain from
decompression sickness can feel different from the pain caused by exertion, bumping your
arm or straining a muscle. For example, with a typical joint injury, keeping your limb still or
supported will usually lessen the pain, but not with decompression sickness. Some divers
describe it as a deep or boring feeling.
One clue that your symptoms are dive-related is if you feel better while breathing pure
oxygen, which helps remove nitrogen buildup from your system. These bubbles can deform
body tissues and block blood flow. If you raise the oxygen content in your blood, more
oxygen gets to the tissues surrounding the nitrogen bubbles and helps reduce injuries and
prevent tissue damage.
I was about 20 minutes out on the dive boat, soaking in the sunshine and speeding
through the gentle waves when my left arm started tingling. Then my arm went numb from
my shoulder down to my fingers. My mind was racing. At this point, I realized this was no
ordinary arm injury. Even though I absolutely hated to fess up and deal with the
embarrassment, I realized that getting in the water would be too risky. I described my
symptoms to the dive leader and boat captain, and they immediately put me on pure oxygen
and turned the boat around.
Sitting there on the boat, my heart was pounding, my head racing, nitrogen bubbles were
potentially blocking off blood flow to who-knows-what parts of my body. Despite my rescue
training, it was overwhelming to realize that this was no practice run and could be a
significant medical injury. As we sped toward the shore, a million things ran through my
mind. Obviously, the dive operators were taking it seriously, and I couldn't decide whether to
be embarrassed, terrified or relieved to be in capable hands. I did my best to avoid eye
contact the entire ride back to shore. I was worried about my condition, but I was also
mortified that I'd ruined the dive for everyone. It sounds like a silly concern considering the
circumstances, but the social torture of being "that girl" was more awkward than a middle-
school dance.
When we reached land, the dive leader immediately took me to a local clinic (oxygen tank in
tow) to speak with a doctor experienced in dive medicine. The doctor asked a series of
questions about the nature of my symptoms including when they started, descriptions of
the sensations I was experiencing and information about my dive profiles. He also
performed some simple motor tests to determine if I still had all my movement capabilities,
to find where the pain and tingling was located, and to establish if the sensation differed in
my left and right arms. Ultimately, he decided that recompression in a hyperbaric chamber
would be the best approach for treatment. Afterward, we'd see if the symptoms got better,
which would indicate that DCS was definitely the cause.
I then spent a very boring five-and-a-half hours in a hyperbaric chamber. During that long
span in the chamber, known as a Table 6 on the U.S. Navy recompression tables, I went
under pressure equal to 60 feet underwater while breathing pure oxygen, which treated
damaged cells, speeding the healing process. The oxygen mask I had to wear looked like
a fighter pilot hand-me-down and made me sound a lot like Darth Vader. For 25 minutes, I
would breathe pure oxygen from the mask followed by a five-minute reprieve without it, so
napping wasn't an option. The doctor regularly checked in over a speaker to monitor my
symptoms in order to determine the length of the treatment. A tender, in my case the dive
leader from my boat, stayed with me in the chamber in case of convulsions resulting from
the high levels of oxygen (and as far as I can tell, to make me drink outrageous quantities of
Gatorade). While we couldn't have engaging conversation, it was comforting to have
someone stuck with me 60 feet under. Overall, the high pressure, small enclosure and
huge oxygen mask made for a hot, sweaty and not particularly pleasant experience. Trust
me, while the chamber pressure imitates being immersed in water, complete with the
need to equalize your ears, there were no thrills on this very dry dive.
Dr. Richard Moon, senior medical consultant to DAN, has compiled data from several
years' worth of DAN statistics that shows early recognition and hyperbaric treatment could
be twice as effective compared with treatment that's delayed 24 hours or more with "pain-
only" or nonspecific symptoms of decompression illness. And with neurological symptoms,
whether they're mild, like Jenn's, or more severe--paralysis, incontinence or mental status
changes--hyperbaric treatment is at least 50 percent more effective when symptoms are
recognized and treated within six hours, compared to those with a delay of 24 hours or
more.
The treatment was moderately painful, causing shooting electrical pains and tingles
throughout my arm as tissue and nerve cells mended. As I lay in the chamber, thinking
(since there isn't much else to do), it was hard to decide which feelings were real and
which were caused by my churning imagination. When you start focusing on something
hard enough and long enough knowing that your reported symptoms determine your
treatment, it's hard to decipher the genuine from the imagined. It was a relief when I
emerged from the chamber feeling much better. No tingling. No numbness. Not only was it
comforting to discover that my symptoms had significantly improved, but it also validated
that DCS was the correct diagnosis. That night and the following day I was still
experiencing some periodic pains and tingles, and I wasn't allowed to fly back home until
my DCS was resolved.
I ended up taking two shorter rounds in the hyperbaric chamber, known as washout
treatments, until my residual symptoms were almost completely gone. Two days after
originally planned, and after a lot of hassle changing plane tickets, I was finally allowed to
fly home. Luckily, I made it through relatively unscathed, not including the substantial hit to
my ego.
I left knowing that I would follow up my treatment with a dive specialist in Miami. Although I
didn't have any reccurrence of major symptoms, I still had strange tingles and shooting
pains every now and then, so after much discussion I decided to do another chamber
treatment. After 10 cumulative hours in the chamber, I could think of about a billion things I
would rather do, but one final washout treatment eliminated all of my symptoms for good.
Minor symptoms, including numbness or even mild paralysis, may persist in some cases.
It often takes time for divers to get complete resolution of their injuries after all hyperbaric
treatments are finished. The body's natural healing process resolves many of the
remaining, less-serious, symptoms. A parallel for this would be a traumatic injury where
surgical repairs closed the wounds, but it takes time for the body to heal itself completely.
The unanswered question of why this incident happened still looms in my mind. It's
frustrating not to have definitive answers, and I have found that this is one of the most
disconcerting aspects of dive medicine. There were other divers with profiles very similar to
my own who were just fine, so what caused my DCS incident? The most likely answer is
dehydration, but I'll never know for sure.
Jenn's Advice
Diving insurance is imperative. After
much debate I, luckily, invested in dive
insurance right before the trip. It saved
me thousands and thousands of dollars,
and ultimately provided peace of mind.
Dive insurance is reasonably cheap,
but if you end up using it, it's priceless.
Dive conservatively. Following your computer or tables reduces your risk of decompression
sickness but never eliminates it (after all, I was well within my computer limits).
Stay hydrated! Dehydration is an important contributing factor to higher DCS risk. I thought
that I was chugging down the fluids, but it's easy to lose track between fish sightings and
sightseeing. Sun and bone-dry tank air can rapidly deplete a body's water content. Make
hydration a priority in your dive plan. (Beer doesn't count!)
Don't be too proud to listen to your body or stop a dive if you have ANY doubts. None of us
wants to admit it. It's humbling, frustrating and downright embarrassing, but it's a far better
choice in the long run. I hate to think what might have happened if I had ignored the signs
and gotten back in the water.
What to do if you think you have DCS
Get on oxygen as soon as possible. It's your first line of defense and the only thing that'll
help besides medical treatment.
Call for help. While you're breathing in the pure stuff, call, or have someone else call, local
emergency services and arrange immediate transportation to a medical facility for
evaluation and treatment.
* If you need advice, call DAN any time, 24 hours a day, 365 days a year. DAN's medical
staff will help evaluate your symptoms and find you appropriate medical facilities and
nearby recompression chambers.
DAN Emergency Information
Diving Emergencies
+1-919-684-4DAN*
DAN America (+1-919-684-4326)
Collect EMERGENCY calls accepted
+1-919-684-9111*
DAN Latin America
Collect EMERGENCY calls accepted
Non-Diving Emergencies
1-800-326-3822*
DAN TravelAssist
Collect calls +1919-684-3483
* Available 24 hours / day
DAN TravelAssist must arrange all transportation prior to evacuation. Provided by MedAire
Inc.
Non-Emergency Dive Questions and other DAN Questions
+1-919-684-2948
Available M-F 8:30 a.m.-8 p.m. ET
By Eric Douglas and Jenn Loder
One woman's firsthand account of DCS, with commentary from the DCS experts at the
Divers Alert Network.
No one likes to admit they're bent. It means they've done something wrong. Errors in
judgment and planning mistakes can lead to decompression sickness (DCS), but more
often than not, it's a seemingly random event--the same dive profile you've done 10 times
can lead to problems on the 11th, and you may never know why. What follows is the
account of one woman, Jenn Loder, who suffered a DCS hit while on vacation in the Turks
and Caicos. I'll pause her story periodically so my colleagues at the Divers Alert Network
and I can shed some light on her experiences.
DCS briefly crossed my mind when my left shoulder
started to ache at the end of my third day of diving,
but I quickly dismissed it, thinking my overactive
imagination was getting the better of me. After all,
I was diving conservatively; I stayed well within
my no-decompression limits, did my safety stops
and ascended slowly. I chalked up the ache to
bumping my shoulder or straining a muscle and
headed for bed.
This is a classic case of denial. Divers often look
for and find other reasons to explain the pain,
numbness and tingling they're feeling, and though
Jenn felt concerned enough to check her rescue
manual, she looked for reasons why it couldn't
be DCS rather than acting on the reasons that
it could. In 14 percent of cases reviewed by Divers Alert Network, divers reported
experiencing symptoms before their last dive, meaning they noticed something was wrong
and still went back into the water, adding more nitrogen to their bodies and potentially
making the situation much worse. "Divers don't call DAN because they have symptoms,"
says Joel Dovenbarger, vice president of DAN Medical Services. "They call us because the
symptoms they have won't go away."
The next morning, thoughts of colorful reef fish, graceful rays and walls dropping off into
forever filled my mind. I couldn't wait to get back on the boat and out on the reefs. But wait.
That nagging ache in my shoulder was still there. Again, those pesky fears of DCS crept
into my thoughts. I even went and checked my rescue diver manual to look for other likely
symptoms: fatigue, chest pain, tingling. Nope, nope, nope. Again, I pushed the thoughts of
DCS aside. I figured it couldn't be possible ... after all, I was a twenty-something in pretty
good shape who didn't drink much or smoke at all–– what were the chances?
As the problem got significantly worse, Jenn made the right decision in recognizing the
severity of the situation and informing the dive staff--before she got in the water. Dive crews
are often the first responders in these cases, and though they're not medical professionals,
they do have working knowledge of the symptoms. It's important to remember that there is
no guaranteed diagnosis for decompression sickness--not even a doctor can give a 100-
percent diagnosis--because the symptoms aren't always obvious. They can be confused
with other injuries or medical conditions and easily written off as unrelated to diving.
The following are some of the most common symptoms reported to DAN, and the first three
are by far the most common.
- Numbness and tingling
- Pain
- Muscular weakness
- Fatigue
- Dizziness
- Headache
- Skin changes
- Nausea
- Vision problems
- Mental changes
- Unconsciousness
- Bladder/bowel dysfunction
- Coordination problems
- Vertigo
- Muscular problems
- Hearing problems
- Tinnitus
within a few hours) is about as clear-cut as it gets. If you feel unusual--divers often describe
DCS symptoms as "something I've never felt before"--you're better safe than sorry. This
"unusual sensation" phenomenon is most true when it comes to pain, as the pain from
decompression sickness can feel different from the pain caused by exertion, bumping your
arm or straining a muscle. For example, with a typical joint injury, keeping your limb still or
supported will usually lessen the pain, but not with decompression sickness. Some divers
describe it as a deep or boring feeling.
One clue that your symptoms are dive-related is if you feel better while breathing pure
oxygen, which helps remove nitrogen buildup from your system. These bubbles can deform
body tissues and block blood flow. If you raise the oxygen content in your blood, more
oxygen gets to the tissues surrounding the nitrogen bubbles and helps reduce injuries and
prevent tissue damage.
I was about 20 minutes out on the dive boat, soaking in the sunshine and speeding
through the gentle waves when my left arm started tingling. Then my arm went numb from
my shoulder down to my fingers. My mind was racing. At this point, I realized this was no
ordinary arm injury. Even though I absolutely hated to fess up and deal with the
embarrassment, I realized that getting in the water would be too risky. I described my
symptoms to the dive leader and boat captain, and they immediately put me on pure oxygen
and turned the boat around.
Sitting there on the boat, my heart was pounding, my head racing, nitrogen bubbles were
potentially blocking off blood flow to who-knows-what parts of my body. Despite my rescue
training, it was overwhelming to realize that this was no practice run and could be a
significant medical injury. As we sped toward the shore, a million things ran through my
mind. Obviously, the dive operators were taking it seriously, and I couldn't decide whether to
be embarrassed, terrified or relieved to be in capable hands. I did my best to avoid eye
contact the entire ride back to shore. I was worried about my condition, but I was also
mortified that I'd ruined the dive for everyone. It sounds like a silly concern considering the
circumstances, but the social torture of being "that girl" was more awkward than a middle-
school dance.
When we reached land, the dive leader immediately took me to a local clinic (oxygen tank in
tow) to speak with a doctor experienced in dive medicine. The doctor asked a series of
questions about the nature of my symptoms including when they started, descriptions of
the sensations I was experiencing and information about my dive profiles. He also
performed some simple motor tests to determine if I still had all my movement capabilities,
to find where the pain and tingling was located, and to establish if the sensation differed in
my left and right arms. Ultimately, he decided that recompression in a hyperbaric chamber
would be the best approach for treatment. Afterward, we'd see if the symptoms got better,
which would indicate that DCS was definitely the cause.
I then spent a very boring five-and-a-half hours in a hyperbaric chamber. During that long
span in the chamber, known as a Table 6 on the U.S. Navy recompression tables, I went
under pressure equal to 60 feet underwater while breathing pure oxygen, which treated
damaged cells, speeding the healing process. The oxygen mask I had to wear looked like
a fighter pilot hand-me-down and made me sound a lot like Darth Vader. For 25 minutes, I
would breathe pure oxygen from the mask followed by a five-minute reprieve without it, so
napping wasn't an option. The doctor regularly checked in over a speaker to monitor my
symptoms in order to determine the length of the treatment. A tender, in my case the dive
leader from my boat, stayed with me in the chamber in case of convulsions resulting from
the high levels of oxygen (and as far as I can tell, to make me drink outrageous quantities of
Gatorade). While we couldn't have engaging conversation, it was comforting to have
someone stuck with me 60 feet under. Overall, the high pressure, small enclosure and
huge oxygen mask made for a hot, sweaty and not particularly pleasant experience. Trust
me, while the chamber pressure imitates being immersed in water, complete with the
need to equalize your ears, there were no thrills on this very dry dive.
Dr. Richard Moon, senior medical consultant to DAN, has compiled data from several
years' worth of DAN statistics that shows early recognition and hyperbaric treatment could
be twice as effective compared with treatment that's delayed 24 hours or more with "pain-
only" or nonspecific symptoms of decompression illness. And with neurological symptoms,
whether they're mild, like Jenn's, or more severe--paralysis, incontinence or mental status
changes--hyperbaric treatment is at least 50 percent more effective when symptoms are
recognized and treated within six hours, compared to those with a delay of 24 hours or
more.
The treatment was moderately painful, causing shooting electrical pains and tingles
throughout my arm as tissue and nerve cells mended. As I lay in the chamber, thinking
(since there isn't much else to do), it was hard to decide which feelings were real and
which were caused by my churning imagination. When you start focusing on something
hard enough and long enough knowing that your reported symptoms determine your
treatment, it's hard to decipher the genuine from the imagined. It was a relief when I
emerged from the chamber feeling much better. No tingling. No numbness. Not only was it
comforting to discover that my symptoms had significantly improved, but it also validated
that DCS was the correct diagnosis. That night and the following day I was still
experiencing some periodic pains and tingles, and I wasn't allowed to fly back home until
my DCS was resolved.
I ended up taking two shorter rounds in the hyperbaric chamber, known as washout
treatments, until my residual symptoms were almost completely gone. Two days after
originally planned, and after a lot of hassle changing plane tickets, I was finally allowed to
fly home. Luckily, I made it through relatively unscathed, not including the substantial hit to
my ego.
I left knowing that I would follow up my treatment with a dive specialist in Miami. Although I
didn't have any reccurrence of major symptoms, I still had strange tingles and shooting
pains every now and then, so after much discussion I decided to do another chamber
treatment. After 10 cumulative hours in the chamber, I could think of about a billion things I
would rather do, but one final washout treatment eliminated all of my symptoms for good.
Minor symptoms, including numbness or even mild paralysis, may persist in some cases.
It often takes time for divers to get complete resolution of their injuries after all hyperbaric
treatments are finished. The body's natural healing process resolves many of the
remaining, less-serious, symptoms. A parallel for this would be a traumatic injury where
surgical repairs closed the wounds, but it takes time for the body to heal itself completely.
The unanswered question of why this incident happened still looms in my mind. It's
frustrating not to have definitive answers, and I have found that this is one of the most
disconcerting aspects of dive medicine. There were other divers with profiles very similar to
my own who were just fine, so what caused my DCS incident? The most likely answer is
dehydration, but I'll never know for sure.
Jenn's Advice
Diving insurance is imperative. After
much debate I, luckily, invested in dive
insurance right before the trip. It saved
me thousands and thousands of dollars,
and ultimately provided peace of mind.
Dive insurance is reasonably cheap,
but if you end up using it, it's priceless.
Dive conservatively. Following your computer or tables reduces your risk of decompression
sickness but never eliminates it (after all, I was well within my computer limits).
Stay hydrated! Dehydration is an important contributing factor to higher DCS risk. I thought
that I was chugging down the fluids, but it's easy to lose track between fish sightings and
sightseeing. Sun and bone-dry tank air can rapidly deplete a body's water content. Make
hydration a priority in your dive plan. (Beer doesn't count!)
Don't be too proud to listen to your body or stop a dive if you have ANY doubts. None of us
wants to admit it. It's humbling, frustrating and downright embarrassing, but it's a far better
choice in the long run. I hate to think what might have happened if I had ignored the signs
and gotten back in the water.
What to do if you think you have DCS
Get on oxygen as soon as possible. It's your first line of defense and the only thing that'll
help besides medical treatment.
Call for help. While you're breathing in the pure stuff, call, or have someone else call, local
emergency services and arrange immediate transportation to a medical facility for
evaluation and treatment.
* If you need advice, call DAN any time, 24 hours a day, 365 days a year. DAN's medical
staff will help evaluate your symptoms and find you appropriate medical facilities and
nearby recompression chambers.
DAN Emergency Information
Diving Emergencies
+1-919-684-4DAN*
DAN America (+1-919-684-4326)
Collect EMERGENCY calls accepted
+1-919-684-9111*
DAN Latin America
Collect EMERGENCY calls accepted
Non-Diving Emergencies
1-800-326-3822*
DAN TravelAssist
Collect calls +1919-684-3483
* Available 24 hours / day
DAN TravelAssist must arrange all transportation prior to evacuation. Provided by MedAire
Inc.
Non-Emergency Dive Questions and other DAN Questions
+1-919-684-2948
Available M-F 8:30 a.m.-8 p.m. ET
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