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Pressure headache and prolonged narcosis (2)

Discussion in 'Diving Medicine' started by Juris Diver, May 26, 2002.

  1. Juris Diver

    Juris Diver Angel Fish

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    I posted this in the basic scuba discussion section, but I thought maybe people who read and answer questions in this section might have additional insight. Here's a copy of my post. Sorry for the redundancy:

    I finished my AOW dives today. The first dive we did was to 100 feet. The deepest I'd been before that was 85 feet at night. All was good until we (there were 4 of us) touched down behind a reef where it was sandy and exactly 100 feet.

    As we all settled down, my heart was really racing. Although I'd never felt nitorgen narcosis before, nothing that anyone has ever told me about it and nothing I've read ever mentioned increased heart rate as a symptom. I'll admit that not knowing whether my increased heart rate was normal made me feel a bit of anxiety (just a bit). At the same time, I was feeling the increased pressure, especially in my head. It felt like my mask strap was being tightened by a vice around my skull. We did a math problem (17+6+3) and I confidently wrote = 36 on my slate (much to everyone's amusement). :D

    Anyway, we had a pretty strong current to fight on the way back up and I was narced the whole way - kinda made controlling my safety stop a bit more interesting than usual. I expected to start feeling normal again after we ascended a bit, but even after we were out of the water for 1/2 hour, I was still pretty kooky and I had a pretty bad headache that hasn't completely gone away even now (deep dive was around 10:00 am, it's now about 8:00 pm). I did the 2 other dives because they were low key (naturalist and search and recovery), but I couldn't stop thinking if maybe something out of the norm happened to me or if maybe for some reason I can't handle the pressure at greater depths. My narcosis didn't really clear until after all my dives and after I took a nap during the boat ride back to the harbor. Maybe I should have aborted the other dives, but I told the instructor I was with about my symptoms and he didn't seem concerned because physically, I felt fine (no sore joints, etc.).

    Has anyone else experienced a pressure headache or had their narcosis last for extended periods of time?

    Thanks in advance.
     
  2. DocVikingo

    DocVikingo Senior Member

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    Hi Juris Diver,

    As regards what was happening at depth, most divers describe the potentially dangerous phenomena of nitrogen narcosis as involving euphoria, and a sense of security & well-being. Much less often it involves feelings of distinct unease. A description limited to an increased heart rate & tightening sensation around the head is one with which I am not familiar. On the other hand, around 100' does seem to be the magic number for many divers, and your arithmetic calculation error could have resulted from narcosis.

    Given your report of fighting a pretty strong current, your increased heart rate may have been related to exertion as opposed to narcosis. Once you began to focus on your heart, this in turn may have triggered your slightly anxious feeling. Also, with the perception of anxiety it's sometimes hard to sort out which occurs first, somatic sign/symptoms (e.g., increased heart rate, tightening sensation around the head) or subjective feelings. Remember, this was your deepest dive to date & seemingly a somewhat challenging one.

    In any event, whether or not you had some narcosis at 100' whatever you were experiencing post dive was not nitrogen narcosis. This is a highly transient state brought on when excess nitrogen in the blood is absorbed into central nervous system tissues. It essentially disappears as soon as the diver ascends to a depth where the PPN2 is no longer toxic--often only a matter of 10' or so. Based on your apparent dive profile, it would be nearly impossible to be narced on your safety stop. And, nitrogen narcosis simply cannot exist once one is back at normal atmospheric pressure & breathing ambient air.

    I suspect that your constellation of symptoms, and most especially the headache, are the result of CO2 retention. This is the most frequent, although by no means only, cause of headache in divers and results from taking too few and/or too shallow breaths. Overly rapid, shallow breathing or breath-holding can occur in divers who for whatever reason are not taking continuous, slow, deep breaths. These headaches can be throbbing, long-lasting & resistant to analgesics. Increased CO2 levels can also be associated with increases in respiratory & pulse rates and blood pressure, and decreases in mental acuity.

    This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.

    Hope you are feeling better soon.

    DocVikingo
     
  3. Uncle Pug

    Uncle Pug Swims with Orca ScubaBoard Supporter

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    Good Morning JD,
    The increased heart rate/anxiety was a feed back loop...
    The tightness in your head was sinus/mask squeeze...
    The math error was minor narcosis plus the above...
    The headache was CO2 retention from the swim...
    The prognosis is excellent w/many future dives...
    The disclaimer: I don't want you for a patient...
    The RX: relax, relieve mask squeeze, enjoy...
    The math problem? I got 17x6x3= 306...
    :wink:
     
  4. Juris Diver

    Juris Diver Angel Fish

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    Thanks Doc!

    I feel fine now (morning after). I'm really not sure what brought on the increased heart rate in addition to the fact that we were really humpin it on the way down. I was using a new set of fins and the increased effort and pace probably sped up my heart a bit. My mask was also leaking ALOT and I was constantly clearing it and my eyes weren't too happy.

    Maybe the equipment concerns, the pace of our descent, and the fact that this was the first time I'd been narced caused my anxiety (rather than feeling euphoric, I thought something was wrong). I'm not saying that the entire experience sucked, it was just more like I'd eaten a bunch of shrooms and they kicked in while I was down there!

    As far as the prolonged kooky feeling, it's definitely possible that I was taking too shallow of breaths on the way back up. That current was pretty strong and we were working hard. Maybe the increased nitrogen loading messed me up as you described.

    With respect to my headache, I'm one of those people that can get a headache if I wear a baseball cap too long. After reading your advice about narcosis, I'm pretty comfortable that I'll be better able to handle the situation next time; however, I'm concerned that I won't be able to handle depth due to my susceptibility to headaches from pressure. What do you think?

    Thanks again. Your feedback is one of the reasons I love this board.
     
  5. Juris Diver

    Juris Diver Angel Fish

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    Hey UP, thanks for replying, I was hoping to get your input as well.

    What is a "feedback loop?"

    I thought that perhaps the mask squeeze caused my headache, but now I'm now wondering if I would have gotten a headache if I'd not been wearing a mask. In other words, I wonder if the headache was from the CO2 plus swim, the squeeze, or if I'm just susceptible to pressure headaches.

    Thanks for your input. :)
     
  6. Uncle Pug

    Uncle Pug Swims with Orca ScubaBoard Supporter

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    Feedback loop: you are anxious and watching for symptoms and that causes your heart to beat faster which you interpret as a symptom and become more anxious and sure enough your heart is beating even faster and....

    When you said in your last post that your mask was flooding I thought that perhaps cold water exacerbated the the headache...
    The fact that the headace lasted post dive points to CO2 retention...

    btw CO2 is 200 times as narcotic as air... working hard at depth on air is asking for the *dark narc*!
     
  7. DocVikingo

    DocVikingo Senior Member

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    Hi Juris Diver,

    Good that you feeling back to normal.

    There is no apparent reason for you to be concerned about "susceptibility to headaches from pressure." My prediction is that if you monitor your breathing and take continuous, slow, deep breaths, and avoid choppy, rapid, shallow breaths, you won't have this problem again. You have been diving long enough to complete AOW, and have been to 85' before, yet make no mention of headache prior to this one. If you were "susceptible," the diving you have already completed likely would have resulted in at least some headaches.

    You'll also want to stay relaxed, and feel free to rise a few feet in the water column when you experience symptoms you believe may be narcosis. If it is narcosis, it should quickly pass.

    Happy diving.

    DocVikingo
     
  8. DocVikingo

    DocVikingo Senior Member

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    A few questions for Uncle Pug:

    1. "The tightness in your head was sinus/mask squeeze..."

    I'm curious as to the basis for this diagnosis(es)? Mask squeeze strikes me as rather unlikely since the poster mentions frequent flooding & clearing of his mask. Additionally, he reports none of the signs of serious mask squeeze, such as marked mask imprint on the face, corneal injection, conjunctival hemorrhage or epistaxis.

    As for sinus squeeze, again there are no signs or symptoms of this, like sinus pain, tooth pain or epistaxis. There also is no reported history, past or present, of sinus problems. On what basis would you suspect inadequate ventilation?

    2. "The math error was minor narcosis plus the above..."

    How do you know the math error was not due to anxiety, or C02 related confusion?

    3. "CO2 is 200 times as narcotic as air.."

    I'm a little confused by this statement. What is your reference source & what are you trying to convey?

    Thanks,

    DocVikingo
     
  9. Uncle Pug

    Uncle Pug Swims with Orca ScubaBoard Supporter

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    1. */ *= *and/or*
    The air spaces associated with the head that would respond to depth pressure are the sinuses and mask. Barotrauma with the evidentiary signs you mention would not necessarily be present with a slight mask or sinus squeeze...
    It wasn't until his second post that he mentioned flooding and clearing the mask... and then I added that perhaps the cold water was exacerbating the the headache.
    To what do you attribute the *tightness* JD describes as his mask straps being pulled tight?

    2. "...plus the above" includes anxiety...
    JD mentions everything is fine on descent and settled in the sand so I would not expect CO2 retention at this point... certainly none that would cause confusion. Plus the headache onset is 1/2 hour post dive... this would indicate that CO2 retention was later in the dive on the ascent fighting current.

    3. *200 times* is hyperbole... but not by much...
    A Google search of the Meyer-Overton rule will get you started:
    http://www.google.com/search?hl=en&ie=UTF8&oe=UTF8&q=meyer-overton
    CO2 itself has (according to The Fundamentals of Technical Diving - J. Jablonski p. 57) 130 times the narcotic potency of nitrogen.
    Also note that nitrogen narcosis increases CO2 retention.

    What I am trying to convey is that deep air diving is fraught with danger and nitrogen narcosis>CO2 retention>CO2 narcosis is a bad scene.
     
  10. BillP

    BillP Senior Member

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    Hi Uncle Pug:

    Your Google search might get DocV started, but it's likely to get him started in the wrong direction (grin). The "Meyer-Overton rule" claims that there is a direct correlation between a gas's solubility in lipids and its potential narcotic effect. CO2 is about 13 times more soluble than N2 in lipids, so the Meyer-Overton rule would suggest that CO2 should be about 13 times more narcotic than N2- not 130 times. But the "130 times" number you quoted is probably more accurate. CO2's mechanism of causing narcotic-like effects seems to be different from nitrogen's, and is not explained by the Meyer-Overton rule. (As an aside, some of the same researchers that found CO2 more narcotic than N2 also found O2 3-4 times more narcotic than N2, but that's a whole other discussion.)


    Just out of curiosity, what do you consider "deep air diving" and at what depths and under what conditions would you change to what other breathing gases and why?

    Bill
     

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