It is quite difficult to make a thorough analysis without the graph of the dive profile, not the description. Suffice to say, lets assume the dive was done properly: ascent rates, multi-level dives under NSL, air.
Given the risk of NSL dive as ~ 1/10,000 dives, most folks should not get bent in their lifetimes of NSL diving. Therefore, this unexpected DCS, which reads as DCS 2 plus skin bends, is a trigger for a workup, as Genesis suggested. This is because the only reason for considering PFO evaluation and closure, as Jim describes, is prior history of DCI and a wish to continue to dive. DCS 2 plus skin bends is commonly associated with PFOs.
However, PFO do grow with age, and a negative test can become positive as the walls weaken and the PFO widens.
Repairs are not permanent either, and what little data available shows that non-open heart closures, like the Amplatz occluder, sometimes move out of position, leak, and form clots. One may be able to dive again after closure, if DCI is indeed PFO related, but the closure would have to be followed for the life of the diver to catch complications. So far, there have been rare needs for full open heart surgery to correct the occluder's mal-position, a situation that would not happen if alternative measures to reduce DCS risk were done in lieu of surgical closure.
While it reads Jim's need for closure is likely needed, I do not agree with his reasoning, analysis of his data nor projecting it to all divers at large. I agree fully with Genesis and Teubner and those who subscribe to their logic.
Most of the diving literature alludes but ignores that the body is fully of shunts other than PFOs, more commonly lung shunts. These shunts can be physical and permanent anomalies or physiological, meaning they allow large bubbles to pass with normal lung function under specific conditions. Shunts are present in nearly all organs and tissues ... and is increasingly more noticed because of transcranial doppler studies ... that reveal unexplained bubbles in the arterial circulation in the absence of bubbles in the pulmonary circulation.
Given that body shunts are unfixable, the wiser alternative is to optimize bubble reduction strategies fully, before repairing a PFO. A PFO workup, if positive, will provide the diver with 3 options and any one, or combos of all are possible:
bubble reduction strategies
PFO closure
stop diving
Bubble reduction strategies included nitrox on air tables, 02 on safety stops, reduced bottom times, improve fitness, fat reduction etc.,
Quote: (Originally Posted by
Yann A.)
Dear All,
This is a non-rebreather diving incident but as a member of this forum I thought I ask the question here on RBW as it has the highest concentration of knowledgeable people on the net. Here is what happened:
No excessive drinking (only 2 beers during dinner the previous day) or drug usage before the dives or days prior to the dives, no previous condition, healthy diver 36 years old The dives went without ay incident, the profiles were smooth (no ups and downs) and well within the No-deco limits. 1st dive 26.5m for 46minutes, surface interval of 1h14, 2nd dive 26.7m for 55minutes, surface interval 1h35, 3rd dive 21m for 57minutes. Theses dive times all include a minimum 3minutes safety stop and at no time during the dive did the diver went into deco.
15h00, 30 minutes after the last dive of the day, the diver started to feel very tired and weak. No oxygen was available so he’s been given some water and asked to rest. 15h45, the diver complained of feeling loss in the fingers and some “blue-black” marble patches started to be seen on his upper body (chest, back and shoulders) so we started the 4h drive to the chamber. During the trip the diver developed severe pain in the legs that increased as we were driving up to a maximum of 600 to 800m above sea level (no choice as it was the shortest road to the hyperbaric facility.
By the time we reached the chamber at 19h (4h after the last dive) the pain had gone and the skin patches were no longer as blue-black but disappearing slowly. Although we did call the hyperbaric physician on call and she told us the chamber was ready, nothing had been done and we were up to a 2h wait going thru ER process of general examination and chest X rays, till she finally arrived at the hospital. At 22h, the doctor decided not to treat the diver who was said to have a body temperature too high (37 degrees C) and she decided to place him under observation for the night and run a USN table 6 treatment the next morning. No oxygen was given to the diver (except for 30min in the ER when we requested for it). The diver felt only a bit dizzy the next morning but was treated (one run under USN Table 6) and asked not to fly for the next 72h nor dive for 1 month. The diver is now fine.
The purpose of this mail is to try to understand what may have gone wrong to justify this DCI only and not on the way the emergency has been handled we know what the loop holes were and will use a different dive operator the next time.
Thanks for your help to understand what can have triggered this DCI.
Yann.