>A: It is a natural human tendency to try to establish cause and effect or to "connect the dots." It is helpful to consider possibilities, but it can be counterproductive to self-diagnose or assign blame too quickly. A health-care professional must provide an actual diagnosis, and the pertinent facts must be viewed objectively and within the proper context.
>Certainly joint aches, headache, dizziness and weakness are among the signs and symptoms associated with DCS, but we must evaluate those signs and symptoms in the context of the facts. This diver reported no symptoms after diving. The surface interval prior to flying was within the recommended guidelines (a minimum of 18 hours after multiple dives). Think about why it is considered safe to fly after waiting the recommended time: Studies show that after that period nitrogen levels in the body are no longer sufficiently elevated to cause symptoms during a routine commercial flight. If by some odd chance a diver had enough residual nitrogen to cause a problem, the symptoms would likely occur during the altitude exposure. This diver did not report any signs or symptoms during her flights. The chances of nitrogen having anything to do with this diver's symptoms are essentially nonexistent.
>Most divers understand, at least intellectually, that a diver can do everything right and still sustain a decompression injury. However, most seem to have difficulty accepting this concept when it actually occurs. The overwhelming number of cases diagnosed as DCS have no discernable cause (other than breathing compressed gas at depth and subsequently returning to the surface). But divers often try to find some factor to blame. This is speculation, however, and can be counterproductive.
>If you experience symptoms after diving please do not decide on your own what the diagnosis should be. Get a medical evaluation. DAN is available for consultation with medical professionals as well as directly with divers. Always consider your symptoms within a proper context — don't connect the dots.
— Marty McCafferty, EMT-P, DMT
>Q: I understand that feeling tired after a dive may be a symptom of decompression sickness, but I almost always feel tired after diving. Should I be concerned?
>The mechanism behind fatigue as a symptom of DCS remains elusive, although it is possibly a response to a cascade of physiological events taking place in various tissues. It could be through direct stimulation of nervous tissues or indirectly through the stimulation of other tissues. It is possible that the attention currently being directed toward identifying biochemical markers of DCS will help resolve the questions. In the meantime, it is reasonable to say that DCS represents a complex, multifocal response to a decompression injury. Unusual or "undue fatigue" (that in excess of normal fatigue for a given individual and diving exposure) is a recognized symptom.
— Neal W. Pollock, Ph.D.
>Q: My doctor recently put me on Coumadin. Could diving while taking this medication cause me any problems?
>Some physicians trained in dive medicine may be willing to endorse recreational diving for these patients provided:
- the underlying disorder or need for anticoagulants does not put the patient at increased risk of an accident, illness or injury while diving.
- the patient understands the risks and modifies his or her dive practices to reduce the risk of ear, sinus and lung barotrauma as well as physical injury. This includes avoiding forceful equalization — equalization must come easily for these people.
- the patient dives conservatively, planning short, shallow profiles to reduce the risk of decompression illness, which can involve bleeding in the inner ear or spinal cord.
- the patient avoids diving in circumstances in which access to appropriate medical care is limited.
— Dan Nord, EMT-P, DMT
>Q: When trying to provide rescue breaths in the water to an injured diver, why can't I use my spare regulator's purge button? That seems easier to me than trying to manage a pocket mask.
>A: Using the purge button of a second-stage regulator has been proposed many times, but any advantage it may seem to offer does not outweigh the potential risks and complications.
>If the regulator mouthpiece is not already in the unconscious diver's mouth, trying to replace it can be difficult and time consuming. Without a good seal and a means to occlude the diver's nostrils, any attempts to ventilate will be unsuccessful. Even if the mouthpiece can be successfully placed in the diver's mouth there is a risk of it pushing the relaxed tongue to the back of the throat and blocking the airway.
>Delivering rescue breaths using a pocket mask or similar method provides tactile feedback via changes in pressure required to ventilate the lungs; supplying rescue breaths with the purge valve eliminates this important feedback. Using a regulator's purge valve also precludes the option of supplementing the gas with 100 percent oxygen.
>Rescue methods that are currently taught by dive-training agencies are the result of years of practical experience. Purge valves were never designed to function as rescue equipment. When ventilating an injured diver, rely on established methods.
— Marty McCafferty, EMT-P, DMT
>The DAN Medical Information Line is here to answer all your dive-related medical questions. You can reach the medical staff during regular business hours (Monday through Friday, 9 a.m. to 5 p.m. ET) by calling +1-919-684-2948, ext. 222. You can also submit an email at DAN.org/Contact.
>© Alert Diver — Spring 2014