Here is a great post regarding carbon dioxide in rebreathers:
I'm sure that many of us in the technical diving community can benefit from the wealth of information by freediving guru Grant Graves on his great new blog, Precision Diving. He gave some amazing presentations at this year's Oztek conference. Check it out here.
Approximately a decade ago, I experienced a decompression illness hit while exploring The Pit in Mexico’s Yucatan Peninsula. Since that time, I have tried to share my experiences openly to help other divers understand that getting bent is a sport’s injury that we should be talking about. Not to belittle the serious of some DCI hits, I just think that we can all learn from each others’ experiences.
To begin with, there are two important things to ensure when you are technical diving. You should have supplemental oxygen available for treatment and a means to reach out to the emergency medical service and DAN or its equivalent.
I haven’t been bent in America, but I have taken plenty of fellow divers out to the local chamber for treatment. Having done this before, I can offer some other simple logistical advice if you live in or are visiting America, a country lacking a medical safety net for its citizens.
Tell your buddy how to find your car keys, wallet, DAN card, health insurance information and emergency contact information. Share any medical issues that might be pertinent to diving risk assessment or treatment.
Ensure there is a way to call EMS and/or DAN. Know how to reach the closest hospital and local chambers.
Carbon Dioxide – Actual Case Discussed at Summit
Sponsored by the NACD, this year’s CCR Cave Summit was held at Camp Kulaqua last weekend. The expert’s roundtable is always the most popular part of the day, offering the audience a chance to ask all their burning questions. This year, the audience was divided with approximately one third being aspiring CCR cave divers and the balance already owning and actively participating in the sport. Beyond basic merits of individual units, the crowd was extremely interested in the topic of carbon dioxide and how it may be responsible for contributing to the deaths of CCR divers. As I have discussed previously in this blog, it is not something that can be determined as a contributing factor at the time of autopsy unless there was some sort of obvious mechanical failure in the rebreather or its preparation. Jeff Gourley shared a personal account about when a mushroom valve folded up in his mouthpiece, causing rapid carbon dioxide build-up that almost cost him his life. Literally moments into his dive, he detected that something was wrong and bailed to open circuit. He described difficulty in getting the mouthpiece into his mouth. After a few sanity breaths, he switched back and almost passed out. Luckily, his advanced training and well-practiced skills got him to the surface on open circuit. The interesting aspect of this incident was that he described the “hangover” as something that lasted all day long with a slow, delayed return to lucid thought.
I am grateful for divers such as Jeff who feel comfortable sharing their worst dives for the benefit of the community. We can all take away several lessons from this incident. Proper pre-dive checks will prevent most of these sorts of failures. Getting off the loop and staying off the loop are critical when you feel that something isn’t right. For the dive buddy or emergency provider – realize that a diver recovering from an incident of high carbon dioxide or low oxygen may be impaired for many hours afterwards. They may be walking and talking, but their brain and body chemistry will take a long time to recover. Photo: Jill Heinerth and Richie Kohler on a recent Sentinel rebreather dive in Florida.