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Phil, this is excellent information, thank you. PLEASE , EVERYONE READ THIS . YOU WILL NOT BE TOLD THIS BY THE TRAIING AGENCIES OR their little lapdog organization, DAN ( the coiner of the "unearned hit"). My opinion is that it is negligent and ciminal that this is not told to all divers up front. My reaction to the first post was out of anger with the dive insdutry liars and DAN which rubber stamps their baloney. Any monkey can see the risk with PFO if they undestand it, and it is irresponsible for the medical community to use statisticzl bull to tell us that it is not a risk when they are clearly leaving out the three conditions that must be present for the DCS to occur; 1) have a PFO, 2) have bubbles, 3) open the PFO. Only the most irresponcbile scumbag con artist liar would tell us that there is no "correlation" yet not bother to tell us the three steps. By the way, ALL dives generate bubbles, so it really comes down to DIVE AND OPEN THE PFO = GET SERIOSULY INJURED. This information below is really top notch, and by the way it has been in the public domain for years and years. By the way. WKPP requires PFO testing for anyone doing the gas dives. I put that in there in 1994, although I was tested myself in 1989. Phil Davies wrote: > > A quick follow up regarding some additional information gleamed from a > quick search of other studies investigating the occurrence of PFO and > decompression sickness, especially given George's "gentle" comdemnation of > my last post suggesting PFO may not be a factor associated with > decompression sickness. > Before I go further for the sake of the list I retract any suggestion I may > have made regarding PFO not being associated with an increased risk of > decopression sickness. In my haste of seeing an article relevant to a > thread on the list I posted it without doing alittle background check to > ensure its validaty. Thanks to George for his comments and provoking me to > look beyond that single article. I only post this stuff so people don't > only remember the one study suggesting PFO does not increase your chances > of suffering decompression sickness. I won't waste your time and bandwidth > with my own opinions on the studies listed below, as any reasonable person > should be able to realise what they mean and what each individual diver > should be doing to reduce their risks. If you're uncertain then reread > George's rebuttal to my initial post. > > Bove (1998) found using statistical analysis of subjects from sport diving, > US navy and comercial diving populations that the presence of a PFO > produces a 2.5 times increase in the odds for developing serious (type II) > DCS in all three types of divers. Unfortunately the author then suggests > that as the odds ratio for developing DCS is small anyway, the risk of > devloping DCS in the presence of a PFO remains small and therefore doesn't > warrant routinue screening by echocardiography of sport, military or > commercial divers. Before you hit that reply button read on... > > Germonpre et al (1998) compared the presence of a PFO in belgian divers > that had suffered from neurological DCS with a control population that had > not suffered any DCS. The statistics are staggering: > Of divers suffering from neurological DCS 59.5% had a PFO while the only > 36% of control divers had a PFO. For divers suffering cerebral DCS 80% had > a PFO compared to 25% in controls and for divers with spinal DCS there was > no differences between those with DCS and the control populations. When > divers with UNEXPLAINED cases of DCS were examined 83% had a grade 2 PFO > (grade 2= score of greater or equal to 20 bubbles contrast passage at rest > or after Valsalva strain). > To summarize, this study suggests that a PFO is strongly correlated with > cerebral DCS. > The authors also noted that there was a striking difference in the method > used for middle ear equalization between divers suffereing cerebral and > spinal DCS. Whereas spinal DCS divers had no problems equalizing (yawning > or light Valsalva), the divers suffering from cerebral DCS reported they > had to "push hard" to clear their ears. This might be relevant as the > Valsalva maneuver induces a major rise in right atrial pressure, a major > cause of blood shunting thru the PFO. > They recomend divers with unexplained DCS or with cerebral DCS hits be > investigated for PFO. If a grade 2 PFO is present then those divers are > advised to follow dive profiles that are very low "bubble-prone" (perhaps > the list might want to comment on what sort of dive this might be???? ie. > <3m) or give up diving. > > I won't bore you all to tears with details of the results of animal models > except to say that using anesthetized pigs with PFO the risks of arterial > bubbles and air embolism is higher. > > Phil Davies > > Bove AA (1998) Risk of decompression sickness with patent foramen ovale. > Undersea Hyperbar Med 25:175-178. > Germonpre, P Dendale, P unger P and Balestra C (1998) Patent foramen ovale > and decompression sickness in sports divers. J. Appl Physiol 84:1622-1666. > > -- > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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