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DCS- It does happen

Discussion in 'Ask Dr. Decompression' started by Vettster, May 6, 2001.

  1. Vettster

    Vettster Instructor, Scuba

    Hi All,
    Went diving today and one of our group got hit (DCS). the group consisted of one of the owners of our local shop, 2 other instructers and myself and another divemaster.
    It was the first dive of the day. We were out looking for new dive sites for the upcoming tourist season. We went down about 105' to a new wreck site. The dive was excellent.
    We stayed down almost to the max on our computers, ascended correctly and because we almost went to the limit on the computers, made a 5 minute safety stop at 15'.
    Everything was by the book. The water was warm.(79F) All divers were hydrated and in good shape. No hangovers.
    Nevertheless, one of our group got out of the water and showed symptoms of DCS.
    He was immeadeatly put on oxygen and brought to shore. Luckily we have a chamber right here. (Veracruz, Mexico) On the way in we radioed in the situation and upon arrival at shore the diver was brought to the chamber. Due to taking quick action, he is expected to make a full recovery.
    Just wanted to write and tell everyone that DCS does happen even when the proper precautions are taken. There is no substitute for having the proper equipment (oxygen, radios etc.)
    Just a reminder, this (DCS) does happen. Lets be careful out there!!!

    Veracruz, Ver. Mexico
  2. DiverInAk

    DiverInAk Nassau Grouper

    Frank, good post. Can you give any more details on how fast the symptoms appeared and what symptoms were present?
  3. Vettster

    Vettster Instructor, Scuba

    Glad you liked the post.
    In this case the symptoms showed up about 5-10 minutes after surfacing and were just like in the books:
    1) Weakness
    2) Fatigue
    3) Arm and leg tingling

    The symptoms seemed to improve on the trip (1 hour) to the shore.

    I remember one of the students in our DM class moaning and groaning about getting a question regarding DCS wrong and then stating: What do we need to know this stuff for? We'll never use it. (I guess theres always one in every crowd)
    Boy, do I wish I had that smart A**es phone number now!!!

    Dive Safe!
    Veracruz, Ver. Mexico
  4. DiverInAk

    DiverInAk Nassau Grouper

    Thanks for the follow up. I'm curious what his previous dive profiles were like. In other words was he diving the day before, or maybe doing repetitive dives prior in the week etc..

    Just curious if there are any other indicators there, as that is always a scary thing to think of getting hit like that. Especially when the computers are generally more conservative than the tables, especially on deep or repetative dives.

    You say that you came up after almost maxing out your bottom time, which means you probably were short of the max allowed on the tables by at least 3 minutes if not more. This makes it hard to understand the hit, without knowing more of the victims dive history.

    But you are right in pointing out that DCS happens. I am planning on buying a DAN O2 unit to take with me on local shore dives. It's a good hour to two hours to a chamber AFTER EMS arrives, so that Oxygen could be really handy.
  5. turnerjd

    turnerjd Divemaster

    # of Dives: I'm a Fish!
    Location: Haute Kontz, France

    However, be warned that the DAN O2 units I have seen don't have any where near enough O2 for a trip that is a 'good hour or two' long.

    For shore dives this is a bit less valid, but certainly, if you plan to dive off a boat at any time

    Imagine the senario....

    -Divers down, and one of them comes up with a problem...
    -You try diver recall
    -Some of the divers come up, however some don't know the recall system and continue
    -it is now 30+ minutes since the bent diver first appeared as the last diver surfaces
    -another 5-10 minutes to get everything sorted out and under way (35-40 mins later)
    -Provided you have been able to contact EMS and they are waiting for you you then have 10 minutes to argue with the EMS not to give entonox (NO2/O2 50:50 mix) but to continue to give O2 - 35-50 minutes after surfacing excluding journey time
    -Now the time to get to the chamber.

    So, it is possibly an hour on top of all the journey times to get some-body to a chamber. Your 1-2 hours is now 2-3 hours. And you want some reserve don't you???

    There is a make of regulator specific for O2 that fits onto MEDICAL O2 bottles (note:- Medical O2 NOT 5%CO2 in O2) and the other end is a face mask with demand valve. They also have a constant feed pipe if you have to use a bag to AV them. - with a setup like this you just get an O2 bottle that is roughly the right size for the time you anticipate as being the longest yourney to a chamber (+ a large margin for safety). Certainly, in the UK a setup like this is cheeper to buy (you don't 'buy' the cylinder of O2), but you do have to pay an annual rental on the O2 cylinder (about £20 - $32)

    My old club had one of these, and then 4 BOC 'D' size cylinders. The further away from help we were, the more cylinders we took.

    I would also like to remind everybody that a lot of EMS people don't deal with DCS, and will immediately put them on their funny Entonox mix (50:50 NO2 and O2) as this is a good relaxant/painkiller/mild anaesthetic/narcotic mix but is rather less good for the diver. If you are going to have an O2 Kit it is probably worth having a slate similar to the PADI Rescue management slate in there as well. This has (IF I remember correctly) some words on it that even the most stupid of EMS people should understand about giving O2 and not Entonox.

    Dive safe!!

    Jon T

    PS for americans - I don't know the US name for entonox - sorry guys!
  6. Vettster

    Vettster Instructor, Scuba

    I will see him this weekend and ask about the dive profiles. I know this was his first dive of the day and if I remember correctly the weather was terrible the previous week, so I am guessing he had not been diving for 5 to 7 days. But I will confirm.

    One other interesting thing I found out was that this particular diver had been hit previously. (Over a year ago)

    Jon T is right about the quantity of oxygen. Time flys in a situation like this. We had the standard DAN cylinder (640 liter ? does anyone know the capacity of the bottles?) and it lasted just under an hour. It finished up about 5 minutes from the shore.
    There was someone waiting on shore with another bottle.

    Dive Safe,
    Veracruz, Ver. Mexico
  7. Vettster

    Vettster Instructor, Scuba

    Hi all,
    Just thought I would update you all on the situation.
    I found out that the diver had not been diving for the previous 5 days.
    Also, they did 3 chamber treatments (I do not remember the depths) and it was recommended that he not dive for at least 30 days.
    Is there any relation between repeat occurances of DCS? Once it occurs is the diver more prone to attacks?

    Dive Safe,
  8. devjr

    devjr Manta Ray

    DAN has a rebreather set which extends time out to about 4 hours. I've never used one but seems like a good idea.

    I got hit while diving near Bimini last year. I'm an older diver but in good shape and with 40 years experience. The mistake I made was complacency. I was diving alone which I've often done over the years. This dive was what I call routine reconnaissance over a coral reef. The only thing different about it was I was using a lot of new gear, a 100cf hp tank and Apollo Biofins among other things. The only vintage equipment was my trusty Scubapro DCP. For divers who may not have heard of this, it is a gas integrator meter, not a "computer" as such. It has a large dial with decompression zones displayed as red sectors, etc.

    The dive took place two hours before dusk and at the start I was already feeling a bit tired and dehydrated. This is because for the previous 4 hours I had been freediving and spearfishing at another site to depths of 50 feet. The SCUBA dive was uneventful as I swam in a 1 knot Gulfstream current. I was growing bored and a bit more tired as the light slowly dimmed with the setting sun. I paused to watch a shark, then glanced at my pressure gauge, 1100 psi remaining. Seeing there was plenty of air and no worries I made a slow ascent from 90 feet to the surface WITHOUT checking my DCP. This is the compacency part. I only used 2/3 of a tank, just wanted to climb the ladder, get warm and dry and hoist anchor.

    Ten minutes after surfacing, putting away gear, I glanced at the DCP. I was shocked to see the needle in the "caution" zone, and that after 10 minutes on board.

    I crossed my fingers but that didn't help. I was hit by severe stomach and back pain and my right leg became paralyzed. My buddies took the boat in and we called for evac to Miami. Spent a week in hospital.

    I am back to normal more or less with a few minor residuals like morning gimp(heh) and a bit of tingling in the foot now and then.

    The indirect causes of the bends were the Biofins and the large capacity tank. The fins require almost no effort to buck the Gulfstream and I used about 20% less air than normal. Hence, my bottom time was greater than would have been indicated by my normal air consumption. The large tank gave the illusion of safe margins. Also, and this is a more direct cause, the doctor said my dive was "repetitive" relative to the freediving. Even though my SCUBA dive was the first in some time, there was residual N2 from the free diving(A guess, I was already in Group C or D when I splashed in). Analysing the depth gauge and the DCP (which I later ran a calibration check on), the dive was 90 feet for approximately 30 minutes. Post dive recheck of the tank showed that I had got bent while using 71 cf of air.

    Dumb mistake. The moral is that dive accidents are usually due to human error, not equipment. New equipment, old equipment, redundant equipment, doesn't matter in my opinion, at least for "non technical" diving; what matters is the diver, his conditioning, knowledge and state of mind. I could have been diving with my 40 year old Navy triples and double hose regulator and had a safe dive if my head was right.

    I'll be taking oxygen with me from now on. Not the wimpy little bottles but SCUBA tanks set up for in water decompression and on board treatment. Got my head right, too.
  9. Dr Deco

    Dr Deco Medical Moderator Staff Member

    # of Dives: I just don't log dives
    Location: Issaquah [20 miles east of Seattle], Washington.
    Dear readers:

    With DCS of a neurological form present within 10 to 30 minutes, this sounds like a question of vein-to-artery arterialization. Gas bubbles form in the tissues, are released into the vena cava, and then pass either through a pulmonary (lung) shunt or a patent foramen ovale (PFO). This pressure reversal could occur with exertion of the form that resembles a Valsalva maneuver (eg, lifting or straining). This momentarily reverses the left-to-right pressure gradient in the artria of the heart.

    The fact that this has occurred before makes me suspect the possibility of easy arterialization in this individual.

    Dr Deco
  10. devjr

    devjr Manta Ray

    I agree, but who are you referring to? I've only been bent once. I don't mind telling it like it is but let's keep the story straight.

    Here's a juicy one for you, the visiting doctor on Cat Cay thought I had a "strained back". The staff at Mercy disagreed to say the least. It wasn't fun. I'm a rather stoic person but my buds were scared. More, to show how sh*t rolls down hill, one of the fellows toting the gurney to the chopper strained himself, developed a hernia and had to be operated on a couple weeks later.

    That's not the worst. My buds got blown out, spent the rest of the trip in Alicetown wolfing down the fish and lobsters, the majority of which I had caught that morning. They mention this whenever I talk about the hospital food, now THAT is a whole 'nother story.

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