Eleventh Hour and Decompression Chambers

By Eric Wolff | December 5, 2008 10:51 pm

Last night on Eleventh Hour, some evil gene therapists had a plan to make the athlete of the future. They had figured out a way to use gene therapy to stimulate muscle production in athletes, but they had to test it first, so they selected the athletes siblings, figuring the siblings would be genetically similar and possibly have similar responses. So, the evil scientists put their genetic cocktail into a virus (as is common enough in gene therapy) and then they secretly switched the siblings’ flu shots with Folgers Cryst– I mean, with the virus. Unfortunately, it turned out that whenever the recipients of the new stuff got their heart rates up, they tended to collapse from an unexpected case of the bends. It turned out that the gene therapy was causing these people to produce huge amounts of nitrous oxide, which then bubbled up in the blood, causing a severe case of the bends.

Part way through the episode, one of the victims, Isaac, collapses while jogging. Our intrepid hero, Dr. Jacob Hood, rushes him  to the hospital and then has his comrade-at-investigations, Rachel Young, put out a Mayday for a decompression chamber. Amazingly, they locate a mobile chamber and have it rushed to the hospital (normally they fly patients with the bends to a chamber, rather then bring the chamber to it).  Once ensconced in the chamber and under high pressure, Isaac’s twitching stopped.

Scientifically, this chamber business makes sense so far. The bends are caused normally when nitrogen bubbles stored in tissue at a certain pressure are released as the pressure drops. Typically it’s a problem for divers who don’t follow their dive tables carefully: at depth, the nitrogen in SCUBA air gets stored in tissue, and as the divers come back up to the surface, the bubbles are released. It typically causes pain, but can lead to paralysis and death.

But dramatically speaking, the producers needed to ratchet up the tension. So the gene therapy continues to produce nitrous oxide gas at higher and higher rates, which forces the techs to raise the pressure on Isaac to keep the bubbles in his blood. And oh what pressure! Decompression chambers measure pressure in feet of sea water (fsw). They start him at 165 fsw.  Then they raise it to 300 fsw. 500! By the last cliffhanger they’ve maxed out the chamber at 1000 fsw. This is actually ridiculous. Look, SciNoFi makes a strong effort to let SciFi be SciFi, because, hey, who wouldn’t want an all-purpose sonic screwdriver? But sometimes a show just pushes the envelope too far, and this pushed my buttons, big time.

Let’s put that 1000 fsw in context. The all time record for a basic SCUBA dive is held by John Bennett, a famous technical diver, who descended to 838 feet. Isaac, therefore, was 162 feet “deeper” than the all time record. Also, 33 feet of sea water is one atmosphere. So 1000 feet of sea water is 30 atmospheres, enough to at least render poor Isaac completely immobile inside the chamber, and raise serious questions of whether he would be strong enough to inflate his lungs. And man, when Hood has to go inside the chamber to deliver the cure, that must have been a pain in the tuchus. That hyopdermic must have felt like it weight 30 pounds.

Oh yeah, and by the way, even the Navy’s decompression chamber can’t deliver 1000 fsw. It has an operating maximum of 7.5 bars, or about 244 fsw. Okay, we’re not in Fringe territory yet, but tsk, tsk, Eleventh Hour, we’ve come to expect more from you.


Comments (3)

  1. Michael


    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!


  2. Wil

    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.

  3. Elmar_M

    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!


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