Comments on: Oxygen and Rebreathers http://www.scubabrucie.com/dive/2007/01/17/oxygen-and-rebreathers/ Take a peek into the mind of a dedicated diver! Thu, 24 Apr 2008 02:40:55 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: cloudboy55 http://www.scubabrucie.com/dive/2007/01/17/oxygen-and-rebreathers/comment-page-1/#comment-22 cloudboy55 Sat, 27 Jan 2007 14:22:38 +0000 http://www.scubabrucie.com/dive/2007/01/17/oxygen-and-rebreathers/#comment-22 Perhaps this article should be entitled "The importance of air breaks during decompression". I don't really see any reason that using a rebreather requires one to use a a PPo2 - I could take open circuit air breaks as easily on a rebreather as on open circuit. Conversely, I could plan an open circuit dive that includes no air breaks and mimick the effect you're referring to. cloudboy55 Perhaps this article should be entitled “The importance of air breaks during decompression”. I don’t really see any reason that using a rebreather requires one to use a a PPo2 – I could take open circuit air breaks as easily on a rebreather as on open circuit. Conversely, I could plan an open circuit dive that includes no air breaks and mimick the effect you’re referring to.

cloudboy55

]]> By: Stewiebouy http://www.scubabrucie.com/dive/2007/01/17/oxygen-and-rebreathers/comment-page-1/#comment-21 Stewiebouy Mon, 22 Jan 2007 12:34:57 +0000 http://www.scubabrucie.com/dive/2007/01/17/oxygen-and-rebreathers/#comment-21 Are you recommending that we keep the PPO of our nitrox mixes down, if so has there been any research into what is considered an acceptable risk for ppo levels. I have experienced a feeling of agitation and discomfort whilst diving a wreck that I had on previous occasions dived on air, the PPO was 1.6 at a depth of 28 meters. Conditions were good with no other reason for apprehension etc. Could it be possible that the oxygen ppo had somthing to do with it? It was quite a long dive but the feeling evaporated at my fist deep stop, I have never had this feeling since but tend to stick to 1.4 ppo or less Are you recommending that we keep the PPO of our nitrox mixes down, if so has there been any research into what is considered an acceptable risk for ppo levels. I have experienced a feeling of agitation and discomfort whilst diving a wreck that I had on previous occasions dived on air, the PPO was 1.6 at a depth of 28 meters. Conditions were good with no other reason for apprehension etc. Could it be possible that the oxygen ppo had somthing to do with it? It was quite a long dive but the feeling evaporated at my fist deep stop, I have never had this feeling since but tend to stick to 1.4 ppo or less

]]> By: Luke Sanders http://www.scubabrucie.com/dive/2007/01/17/oxygen-and-rebreathers/comment-page-1/#comment-16 Luke Sanders Thu, 18 Jan 2007 09:02:43 +0000 http://www.scubabrucie.com/dive/2007/01/17/oxygen-and-rebreathers/#comment-16 I'd like to see your evidence behind this - it sounds an awful lot like scaremongering to me, and I have very extensive knowledge of how the body works. I think you're referring to pulmonary oxygen toxicity when you talk about the lungs filling with fluid but you're wrong how this works. This is caused by long term exposure to levels of oxygen below that seen in technical diving (perhaps 0.7 bar) and we're talking many hours of exposure. It's caused by the production of oxygen free radicals in excess of what can be scavenged by the protective cells in the lungs. You're looking at 12-16 hours of constant exposure to cause this, though, and it's not really a problem seen in diving. Maybe if you get potted (hence the air breaks in the pot), but not so much in the water. I’d like to see your evidence behind this – it sounds an awful lot like scaremongering to me, and I have very extensive knowledge of how the body works. I think you’re referring to pulmonary oxygen toxicity when you talk about the lungs filling with fluid but you’re wrong how this works. This is caused by long term exposure to levels of oxygen below that seen in technical diving (perhaps 0.7 bar) and we’re talking many hours of exposure. It’s caused by the production of oxygen free radicals in excess of what can be scavenged by the protective cells in the lungs. You’re looking at 12-16 hours of constant exposure to cause this, though, and it’s not really a problem seen in diving. Maybe if you get potted (hence the air breaks in the pot), but not so much in the water.

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