Comments on: Eleventh Hour and Decompression Chambers http://blogs.discovermagazine.com/sciencenotfiction/2008/12/05/eleventh-hour-decompression-chambers-do-not-go-to-900-feet-a-rant/ The science of futurist technologies—and an excuse to soak in sci-fi TV shows, books, movies, toys, and video games. Fri, 20 Nov 2009 21:57:34 -0600 http://wordpress.org/?v=2.8.4 hourly 1 By: Elmar_M http://blogs.discovermagazine.com/sciencenotfiction/2008/12/05/eleventh-hour-decompression-chambers-do-not-go-to-900-feet-a-rant/comment-page-1/#comment-2374 Elmar_M Mon, 08 Dec 2008 20:02:06 +0000 http://blogs.discovermagazine.com/sciencenotfiction/2008/12/05/eleventh-hour-decompression-chambers-do-not-go-to-900-feet-a-rant/#comment-2374 Oh, its another "the evil geniticists" episode from Eleventh hour. Who would have expected that? This show is so clearly antiscience, it makes me barf! It should be on the religion channel! Oh, its another “the evil geniticists” episode from Eleventh hour. Who would have expected that? This show is so clearly antiscience, it makes me barf! It should be on the religion channel!

]]> By: Wil http://blogs.discovermagazine.com/sciencenotfiction/2008/12/05/eleventh-hour-decompression-chambers-do-not-go-to-900-feet-a-rant/comment-page-1/#comment-2353 Wil Sun, 07 Dec 2008 08:48:29 +0000 http://blogs.discovermagazine.com/sciencenotfiction/2008/12/05/eleventh-hour-decompression-chambers-do-not-go-to-900-feet-a-rant/#comment-2353 In addition to the above comments, oxygen becomes poisonous at more that two atmospheres partial pressure (absolute). This is why heliox has such a low oxygen concentration (much lower than the 21% of standard air). This is why nobody can breathe pure oxygen at a depth more than than about 33 feet. This factor alone would have quickly killed the patient in the pressure chamber. Okay, let's say the patient was in pressurized heliox, instead of pressurized air. Two issues there. The first (unimportant) issue is the well known "duck" voice. The second issue is that light atoms like helium conduct heat extremely fast. If a patient is in a heliox atmosphere long enough, he can "freeze" to death even near room temperature, if he is not properly bundled up. In addition to the above comments, oxygen becomes poisonous at more that two atmospheres partial pressure (absolute). This is why heliox has such a low oxygen concentration (much lower than the 21% of standard air). This is why nobody can breathe pure oxygen at a depth more than than about 33 feet. This factor alone would have quickly killed the patient in the pressure chamber.

Okay, let’s say the patient was in pressurized heliox, instead of pressurized air. Two issues there. The first (unimportant) issue is the well known “duck” voice. The second issue is that light atoms like helium conduct heat extremely fast. If a patient is in a heliox atmosphere long enough, he can “freeze” to death even near room temperature, if he is not properly bundled up.

]]> By: Michael http://blogs.discovermagazine.com/sciencenotfiction/2008/12/05/eleventh-hour-decompression-chambers-do-not-go-to-900-feet-a-rant/comment-page-1/#comment-2343 Michael Sun, 07 Dec 2008 02:54:06 +0000 http://blogs.discovermagazine.com/sciencenotfiction/2008/12/05/eleventh-hour-decompression-chambers-do-not-go-to-900-feet-a-rant/#comment-2343 Eric, It seems to me that you are mistaking pressure for gravity. Why would the hypodermic needle feel like it weighed 30 pounds? Pressure on it wouldn't change its weight. The same goes for the patient being not strong enough to inflate his lungs. Perhaps the density of the "air" would be too great. At greater than 200 feet you need a mix of Oxygen and Helium (to avoid Nitrogen Narcosis), and at 400ft + you need to add about 15% Nitrogen back into that mix (the N2 counters effects of just H2 and O2 - in other words a bit of Nitrogen Narcosis is just what you need at that depth!). In any case, the air gets more dense and harder to breath, but the weight of it pressing down on one isn't a bother (since the pressure inside you is equal to the pressure outside of you). Hood could never have gone into the chamber without tremendous effort, and he certainly wouldn't have been able to leave short of a several days. Oh well! --Michael Eric,

It seems to me that you are mistaking pressure for gravity. Why would the hypodermic needle feel like it weighed 30 pounds? Pressure on it wouldn’t change its weight. The same goes for the patient being not strong enough to inflate his lungs. Perhaps the density of the “air” would be too great. At greater than 200 feet you need a mix of Oxygen and Helium (to avoid Nitrogen Narcosis), and at 400ft + you need to add about 15% Nitrogen back into that mix (the N2 counters effects of just H2 and O2 – in other words a bit of Nitrogen Narcosis is just what you need at that depth!).
In any case, the air gets more dense and harder to breath, but the weight of it pressing down on one isn’t a bother (since the pressure inside you is equal to the pressure outside of you).

Hood could never have gone into the chamber without tremendous effort, and he certainly wouldn’t have been able to leave short of a several days.

Oh well!

–Michael

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