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This is a multi-part message in MIME format. ------=_NextPart_000_0039_01C1B2C6.D4E990B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Narcotic level is easy - any increase is more narcotic than no increase. Impairment starts immediately, and just gets worse. As for rigidity due to nitrogen tension, it appears to be relieved by the presence of helium in the same fashion - the more helium , the less tension. We have found that <30% is not going to do a whole lot . 25% is the minimum useful range for deco gas, 30 for diving, and then we are talking <120 feet. For all else we go to at least 35 and prefer higher. After thousands, as in the tens of thousands, of man dive hours in the WKPP doing extreme exposure mixed gas dives over the course of 16 years , and intensely over the last 9 years, these have been our findings. -----Original Message----- From: swanncruz@oc*.ne*.au* [mailto:swanncruz@oc*.ne*.au*] Sent: Monday, February 11, 2002 3:03 AM To: George Irvine; techdiver@aquanaut.com; quest@gu*.co* Subject: Red Blood Cell Rigidity "High partial pressures of nitrogen cause the red cells to become rigid and get hung up in capillaries or damage them. The response of the body to this and the immune response tend to close off the area . Anyone ( but a dive instructor) can see what that means for decompression." Hi George & List, As always, thanks for the info. With respect to red cell rigidity with a high pp of N2, my knowledge of physiology has dulled somewhat over the years, but red cells do distort (squash) as they move through smaller capillaries, which would make the prospect of increased rigidity of the RBC quite alarming. That is, small capillaries are smaller than RBC. Hence, it could be that we see RBCs unable to pass and associated capillary rupture. Do you think there is a threshold partial pressure where the effect of RBC rigidity becomes marked, or is there a linear change? I would think there would be an age variable here as well. If so, did this (theoretical) threshold partial pressure of N2 (causing BBC rigidity) influence the GUE recomended mixes? I realize you are keeping the narcotic values at around or less than 30m. What I am getting at is a "threshold physiologically damaging pp of N2", as well as a narcotic level. We seem to be able to quantify a narcotic value (=level). This is fascinating stuff, and would keep some PhD students going for years. Regards, Jeff the Darwinian. I'm going to send this quick, B4 I confuse myself any further............. ------=_NextPart_000_0039_01C1B2C6.D4E990B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3D"MSHTML 5.50.4522.1800" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV><SPAN class=3D639583411-11022002><FONT face=3DArial color=3D#0000ff = size=3D2>Narcotic level is easy - any increase is more narcotic than no = increase.=20 Impairment starts immediately, and just gets worse.</FONT></SPAN></DIV> <DIV><SPAN class=3D639583411-11022002><FONT face=3DArial color=3D#0000ff = size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D639583411-11022002><FONT face=3DArial color=3D#0000ff = size=3D2>As for=20 rigidity due to nitrogen tension, it appears to be relieved by the = presence of=20 helium in the same fashion - the more helium , the less tension.=20 </FONT></SPAN></DIV> <DIV><SPAN class=3D639583411-11022002><FONT face=3DArial color=3D#0000ff = size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D639583411-11022002><FONT face=3DArial color=3D#0000ff = size=3D2>We=20 have found that <30% is not going to do a whole lot . 25% is the = minimum=20 useful range for deco gas, 30 for diving, and then we are talking = <120 feet.=20 For all else we go to at least 35 and prefer higher.</FONT></SPAN></DIV> <DIV><SPAN class=3D639583411-11022002><FONT face=3DArial color=3D#0000ff = size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D639583411-11022002><FONT face=3DArial color=3D#0000ff = size=3D2>After=20 thousands, as in the tens of thousands, of man dive hours in the WKPP = doing=20 extreme exposure mixed gas dives over the course of 16 years , and = intensely=20 over the last 9 years, these have been our findings.</FONT></SPAN></DIV> <BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px"> <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT = face=3DTahoma=20 size=3D2>-----Original Message-----<BR><B>From:</B> = swanncruz@oc*.ne*.au*=20 [mailto:swanncruz@oc*.ne*.au*]<BR><B>Sent:</B> Monday, February 11, = 2002 3:03=20 AM<BR><B>To:</B> George Irvine; techdiver@aquanaut.com;=20 quest@gu*.co*<BR><B>Subject:</B> Red Blood Cell = Rigidity<BR><BR></FONT></DIV> <DIV><FONT face=3DArial size=3D2>"High partial pressures of nitrogen = cause the red=20 cells to become rigid and<BR>get hung up in capillaries or damage = them. The=20 response of the body to this<BR>and the immune response tend to close = off the=20 area . Anyone ( but a dive<BR>instructor) can see what that means for=20 decompression."</FONT></DIV> <DIV><FONT face=3DArial size=3D2>Hi George & List,<BR>As always, = thanks for=20 the info.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>With respect to red cell rigidity = with a high pp=20 of N2, my knowledge of physiology has dulled somewhat over the years, = but red=20 cells do distort (squash) as they move through smaller capillaries, = which=20 would make the prospect of increased rigidity of the RBC quite=20 alarming.</FONT><FONT face=3DArial size=3D2> That is, small = capillaries are=20 smaller than RBC. Hence, it could be that we see RBCs unable to pass = and=20 associated capillary rupture.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>Do you think there is a threshold = partial=20 pressure where the effect of RBC rigidity becomes marked, or is there = a linear=20 change?</FONT></DIV> <DIV><FONT face=3DArial size=3D2>I would think there would be an age = variable here=20 as well.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>If so, did this (theoretical) = threshold partial=20 pressure of N2 (causing BBC rigidity) influence the GUE recomended=20 mixes?</FONT></DIV> <DIV><FONT face=3DArial size=3D2>I realize you are keeping the = narcotic values at=20 around or less than 30m.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>What I am getting at is a "threshold=20 physiologically damaging pp of N2", as well as a narcotic = level.</FONT></DIV> <DIV><FONT face=3DArial size=3D2>We seem to be able to quantify a = narcotic value=20 (=3Dlevel).</FONT></DIV> <DIV><FONT size=3D2><FONT face=3DArial>This is fascinating stuff, and = would keep=20 some PhD students going for years.</FONT></FONT></DIV> <DIV><FONT size=3D2><FONT face=3DArial>Regards,</FONT></FONT></DIV> <DIV><FONT size=3D2><FONT face=3DArial>Jeff the = Darwinian.</FONT></FONT></DIV> <DIV><FONT size=3D2><FONT face=3DArial></FONT></FONT> </DIV> <DIV><FONT size=3D2><FONT face=3DArial>I'm going to send this quick, = B4 I confuse=20 myself any=20 further.............<BR></DIV></BLOCKQUOTE></FONT></FONT></BOD Y></HTML> ------=_NextPart_000_0039_01C1B2C6.D4E990B0-- -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. 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