Mailing List Archive Mailing List Archive
This is a multi-part message in MIME format. --Boundary_(ID_hs8EKUcJBhxzaUw425yWuw) Content-type: text/plain; charset=iso-8859-1 Content-transfer-encoding: 7BIT * If somebody wants to put that post on here, go ahead* Here it is, WHY WE DO NOT BOUNCE DIVE AFTER DIVING IN THE WKPP It is ok to offgas from the tissues into the blood stream in bubble form in the later steps of decompression as it is a more efficient, faster way of getting rid of the remaining gas ( by reduced pressure ) than by elevated oxygen alone ( which starts taking exponentially more time with greater risk) . However, this depends on having a good lung filter and no shunts. All of you have been PFO tested if you are diving with us. The correct way to ascend from the last stop is one foot per minute for the bigger dives. The greatest potential for offgassing in bubble form is when the pressure is totally removed back to one ATA out of the water. Now you get a real shower of bubbles , relative to what was happening in the water. A good , clean deco with the foot per minute ascent reduces this dramatically . In MOST people, the greatest bubbling occurs out of the water and continues for up to four hours, not even peaking for a couple of hours. In a well vascularized, fit person like me, it is over with in 30 minutes. Don't bet on that with most of you. In ALL people, the bubbles continue to grow in size after the pressure is off. They accumulate like gas into themselves from the surrounding blood or tissues ( if there are bubbles in the tissues or injury sites ) and they grow bigger. This is why you feel pain later rather than earlier if the bubbles are in joints or tissues - they get bigger before they begin to shrink. This is why what starts out as micro bubbles can get by the lungs and grow and get lodged downstream, and you get neurological symptoms later. Now here is the important part. If you understand everything I have said above, then you know that bouncing to 20 feet or whatever to pick up a bottle and immediately returning to the surface is the like giving yourself a home-made PFO: the bubbles in the venous side compress enough to get past the lungs and then will reexpand on the arterial side and lodge in the worst places , the spine and brain blood supplies. You do not want this. If you dive after dive, stay down and let everything reset. Get the bubbles all compressed, and then deco out and ascend accordingly. I do not want support divers diving support within four hours of doing a real dive or deep support. This works out fine, since we have support activities lasting up to 18 to 24 hours and need to rotate everyone. Let me assure you that we have found this out the hard way in the past. Parker used to get hot as hell when it would happen. In those days we had "volunteers", and they would all get bent diving to 20 feet to pick up bottles. We have also seen some severe cases of this where dives were done away from the project with no support, and the players went back for bottles later and got hammered. Don't do it. Also, obviously, do not freedive after a dive. When you want to freedive, do that first and then go scuba diving. ----- Original Message ----- From: George Irvine To: Techdiver@Aquanaut.Com Cc: Cavers@Ca*.Co* Sent: Wednesday, February 06, 2002 6:13 AM Subject: deco posts , repets, etc. start with this -----Original Message----- From: George_Irvine@ Mike, I will put out my repet post and the others in sequence, but first let me mention something here that is being missed. Gas does not transfer from tissues into arteries or veins, it does so into capillaries. The artilleries coming from the heart are huge, thick, elastic , pulsing conduits that get smaller as they branch out until they become capillaries, and then the return to the heart is through veins which are also thick and get larger as they combine to return blood to the right side of the heart. That blood is then sent to the lungs, where the massive network of tiny capillary beds located in about 45,000 square feet of surface area, act as a "filter" for bubbles. The "filtered" and now oxygenated blood which has passed its co2 and other excess gasses to the lung space, goes back to the heart to be pumper through the system again. The whole trip takes about two minutes to happen. You do not bubble into the arteries. If bubbles get into the arteries it is because they passed the filter or were "shunted" over through a PFO in the arterial walls, or because they were momentarily compressed enough momentarily to get past the lungs and then reexpanded as the pressure dropped prior to reaching the capillaries, in which case they lodge in the smaller and smaller vessels and block them. This occurs in bounce diving, as in doing a dive and then bouncing back down to retrieve something, like a deco bottle. This is why we do not allow bouncing in the WKPP, and why we require our support divers to stay out for 4 hours before diving shallow for support. * If somebody wants to put that post on here, go ahead* Most people get the greatest rush of bubbles from the tissues into the blood stream upon surfacing from 20 feet or so. This is why we do that differently, post to follow. Most people tend to bubble for hours after a dive. Most bubbles tend to grow from the surrounding supply of gas before they get smaller and disappear. If the bubbles are in the tissues, yo have pain. The way to prevent bubbles in the tissues is to properly decompress starting deep and at a rate that allows the bubbles to escape to the blood stream. Deep this needs to be done carefully and in solution, shallow you can press the gradient and allow offgassing in bubble form into the blood stream. The difference is that if you screw up shallow, you can go back a little and fix it. If it occurs deep, that makes it impractical and a huge waste of time for nothing. For people wight cardiac or pulmonary shunts, offgassing in bubble form is super dangerous. For those without, it is far more efficient. For those with PFO's, the risk is greatest AFTER they get out of the water for the reasons stated above ( growth of bubbles and continuation of bubble offgassing) I think you can see where I am going to tell you that you need to do your shallowest dives first, do your drills before yo do your dives, and why you can basically ignore repetitive dives using the correct deco. You can NOT ignore them with respect to oxygen exposure. This post is long enough , basic enough and preliminary enough. Now we can go on to the whole bit. --Boundary_(ID_hs8EKUcJBhxzaUw425yWuw) Content-type: text/html; charset=iso-8859-1 Content-transfer-encoding: 7BIT <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.2600.0" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2><FONT face="News Gothic MT">* If somebody wants to put that post on here, go ahead*</FONT><FONT face="Times New Roman" size=3> </FONT></FONT></DIV> <DIV><FONT face="News Gothic MT" size=2></FONT> </DIV> <DIV><FONT face="News Gothic MT" size=2>Here it is,</FONT></DIV> <DIV><FONT face="News Gothic MT" size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>WHY WE DO NOT BOUNCE DIVE AFTER DIVING IN THE WKPP</FONT></DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2>It is ok to offgas from the tissues into the blood stream in bubble form in</FONT></DIV> <DIV><FONT face=Arial size=2>the later steps of decompression as it is a more efficient, faster way of</FONT></DIV> <DIV><FONT face=Arial size=2>getting rid of the remaining gas ( by reduced pressure ) than by elevated</FONT></DIV> <DIV><FONT face=Arial size=2>oxygen alone ( which starts taking exponentially more time with greater</FONT></DIV> <DIV><FONT face=Arial size=2>risk) . However, this depends on having a good lung filter and no shunts.</FONT></DIV> <DIV><FONT face=Arial size=2>All of you have been PFO tested if you are diving with us.</FONT></DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2>The correct way to ascend from the last stop is one foot per minute for the</FONT></DIV> <DIV><FONT face=Arial size=2>bigger dives.</FONT></DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2>The greatest potential for offgassing in bubble form is when the pressure is</FONT></DIV> <DIV><FONT face=Arial size=2>totally removed back to one ATA out of the water. Now you get a real shower</FONT></DIV> <DIV><FONT face=Arial size=2>of bubbles , relative to what was happening in the water. A good , clean</FONT></DIV> <DIV><FONT face=Arial size=2>deco with the foot per minute ascent reduces this dramatically .</FONT></DIV> <DIV><FONT face=Arial size=2>In MOST people, the greatest bubbling occurs out of the water and continues</FONT></DIV> <DIV><FONT face=Arial size=2>for up to four hours, not even peaking for a couple of hours. In a well</FONT></DIV> <DIV><FONT face=Arial size=2>vascularized, fit person like me, it is over with in 30 minutes. Don't bet</FONT></DIV> <DIV><FONT face=Arial size=2>on that with most of you.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>In ALL people, the bubbles continue to grow in size after the pressure is</FONT></DIV> <DIV><FONT face=Arial size=2>off. They accumulate like gas into themselves from the surrounding blood or</FONT></DIV> <DIV><FONT face=Arial size=2>tissues ( if there are bubbles in the tissues or injury sites ) and they</FONT></DIV> <DIV><FONT face=Arial size=2>grow bigger. This is why you feel pain later rather than earlier if the</FONT></DIV> <DIV><FONT face=Arial size=2>bubbles are in joints or tissues - they get bigger before they begin to</FONT></DIV> <DIV><FONT face=Arial size=2>shrink. This is why what starts out as micro bubbles can get by the lungs</FONT></DIV> <DIV><FONT face=Arial size=2>and grow and get lodged downstream, and you get neurological symptoms later.</FONT></DIV> <DIV><FONT face=Arial size=2>Now here is the important part. If you understand everything I have said</FONT></DIV> <DIV><FONT face=Arial size=2>above, then you know that bouncing to 20 feet or whatever to pick up a</FONT></DIV> <DIV><FONT face=Arial size=2>bottle and immediately returning to the surface is the like giving yourself</FONT></DIV> <DIV><FONT face=Arial size=2>a home-made PFO: the bubbles in the venous side compress enough to get past </FONT><FONT face=Arial size=2>the lungs and then will reexpand on the arterial side and lodge in the worst</FONT></DIV> <DIV><FONT face=Arial size=2>places , the spine and brain blood supplies. You do not want this.</FONT></DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2>If you dive after dive, stay down and let everything reset. Get the bubbles</FONT></DIV> <DIV><FONT face=Arial size=2>all compressed, and then deco out and ascend accordingly.</FONT></DIV> <DIV><FONT face=Arial size=2>I do not want support divers diving support within four hours of doing a</FONT></DIV> <DIV><FONT face=Arial size=2>real dive or deep support. This works out fine, since we have support</FONT></DIV> <DIV><FONT face=Arial size=2>activities lasting up to 18 to 24 hours and need to rotate everyone.</FONT></DIV> <DIV><FONT face=Arial size=2>Let me assure you that we have found this out the hard way in the past.</FONT></DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2>Parker used to get hot as hell when it would happen. In those days we had</FONT></DIV> <DIV><FONT face=Arial size=2>"volunteers", and they would all get bent diving to 20 feet to pick up</FONT></DIV> <DIV><FONT face=Arial size=2>bottles. We have also seen some severe cases of this where dives were done</FONT></DIV> <DIV><FONT face=Arial size=2>away from the project with no support, and the players went back for bottles</FONT></DIV> <DIV><FONT face=Arial size=2>later and got hammered.</FONT></DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2>Don't do it. Also, obviously, do not freedive after a dive. When you want to</FONT></DIV> <DIV><FONT face=Arial size=2>freedive, do that first and then go scuba diving.</FONT></DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A title=girvine@be*.ne* href="mailto:girvine@be*.ne*">George Irvine</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A title=techdiver@aquanaut.com href="mailto:Techdiver@Aquanaut.Com">Techdiver@Aquanaut.Com</A> </DIV> <DIV style="FONT: 10pt arial"><B>Cc:</B> <A title=cavers@ca*.co* href="mailto:Cavers@Ca*.Co*">Cavers@Cavers.Com</A> </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, February 06, 2002 6:13 AM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> deco posts , repets, etc. start with this</DIV> <DIV><BR></DIV> <DIV><FONT face=Arial color=#0000ff size=2></FONT> </DIV> <DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma size=2>-----Original Message-----<BR><B>From:</B> George_Irvine@</FONT></DIV><BR><FONT face=sans-serif size=2>Mike, I will put out my repet post and the others in sequence, but first let me mention something here that is being missed.</FONT> <BR><BR><FONT face=sans-serif size=2>Gas does not transfer from tissues into arteries or veins, it does so into capillaries. The artilleries coming from the heart are huge, thick, elastic , pulsing conduits that get smaller as they branch out until they become capillaries, and then the return to the heart is through veins which are also thick and get larger as they combine to return blood to the right side of the heart.</FONT> <BR><BR><FONT face=sans-serif size=2>That blood is then sent to the lungs, where the massive network of tiny capillary beds located in about 45,000 square feet of surface area, act as a "filter" for bubbles. The "filtered" and now oxygenated blood which has passed its co2 and other excess gasses to the lung space, goes back to the heart to be pumper through the system again. The whole trip takes about two minutes to happen.</FONT> <BR><BR><FONT face=sans-serif size=2>You do not bubble into the arteries. If bubbles get into the arteries it is because they passed the filter or were "shunted" over through a PFO in the arterial walls, or because they were momentarily compressed enough momentarily to get past the lungs and then reexpanded as the pressure dropped prior to reaching the capillaries, in which case they lodge in the smaller and smaller vessels and block them. This occurs in bounce diving, as in doing a dive and then bouncing back down to retrieve something, like a deco bottle. This is why we do not allow bouncing in the WKPP, and why we require our support divers to stay out for 4 hours before diving shallow for support.</FONT> <BR><BR><FONT face=sans-serif size=2>* If somebody wants to put that post on here, go ahead*</FONT> <BR><BR><FONT face=sans-serif size=2>Most people get the greatest rush of bubbles from the tissues into the blood stream upon surfacing from 20 feet or so. This is why we do that differently, post to follow. Most people tend to bubble for hours after a dive. Most bubbles tend to grow from the surrounding supply of gas before they get smaller and disappear.</FONT> <BR><BR><FONT face=sans-serif size=2>If the bubbles are in the tissues, yo have pain. The way to prevent bubbles in the tissues is to properly decompress starting deep and at a rate that allows the bubbles to escape to the blood stream. Deep this needs to be done carefully and in solution, shallow you can press the gradient and allow offgassing in bubble form into the blood stream. The difference is that if you screw up shallow, you can go back a little and fix it. If it occurs deep, that makes it impractical and a huge waste of time for nothing. For people wight cardiac or pulmonary shunts, offgassing in bubble form is super dangerous. For those without, it is far more efficient. For those with PFO's, the risk is greatest AFTER they get out of the water for the reasons stated above ( growth of bubbles and continuation of bubble offgassing)</FONT> <BR><BR><FONT face=sans-serif size=2>I think you can see where I am going to tell you that you need to do your shallowest dives first, do your drills before yo do your dives, and why you can basically ignore repetitive dives using the correct deco. You can NOT ignore them with respect to oxygen exposure.</FONT> <BR><BR><FONT face=sans-serif size=2>This post is long enough , basic enough and preliminary enough. Now we can go on to the whole bit.</FONT> <BR></BLOCKQUOTE></BODY></HTML> --Boundary_(ID_hs8EKUcJBhxzaUw425yWuw)-- -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]