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Scientists Keep Rabbits Alive With Oxygen Microparticle Injections
ananyo writes "Rabbits with blocked windpipes have been kept alive for up to 15 minutes without a single breath, after researchers injected oxygen-filled microparticles into the animals' blood. Oxygenating the blood by bypassing the lungs in this way could save the lives of people with impaired breathing or obstructed airways (abstract). In the past, doctors have tried to treat low levels of oxygen in the blood, or hypoxaemia, and related conditions such as cyanosis, by injecting free oxygen gas directly into the bloodstream. But oxygen injected in this way can accumulate into larger bubbles and form potentially lethal blockages."
No, it's not useful for those. You already have an established airway for those. And in CF, the lungs aren't often the killer, these days.
The experimental solutions contained 50-90 mL of O2 per deciliter - to sustain an adult human, you need about 300 mL O2 per minute. At least 300 mL of IV fluid and as much as 600 mL per minute is going to have to go through one hell of an IV. I doubt you could achieve such infusion rates without specialized equipment (e.g., 8.5 French rapid infusion catheter + Level One pump) or multiple intraosseous needles.
Furthermore, this is temporizing just like any other O2 delivery method. Oxygen is essential for life, but eventually you have to clear the CO2, or it's pointless. As a bridge to a secure airway or crash on to cardiopulmonary bypass? Sure, it's not a bad idea, except that the only thing that matters in that kind of life-or-death situation is how long it takes to get it in the room. By the time you get this stuff out of the refrigerator in pharmacy and run it to the OR, ER, or ICU, you could have gotten a surgeon there to do the cricothyrotomy or even a proper tracheostomy.
You can't turn CO2 + H2O into O2 + C(H2O) efficiently unless you're a plant, and you'd have to get the CO2 out of solution quickly (easy) and get more O2 back into solution quickly (hard).
Rebreathers just scrub CO2 from the atmosphere and lock it up as a carbonate. They need not be particularly large, though - the CO2 scrubber on the GE (Datex-Ohmeda) ADU Carestation is about the same size as a pint glass. The rest of the system is the bulky part, and in most situations could actually be done without.
No. The volume requirements alone will rapidly render this useless. To supply an adult human, you would need 300-600 mL of infused volume per minute. Given that an adult has a blood volume of roughly 5 L, you can imagine that you're going to run into problems pretty quickly.
Well, liquids aren't compressible in general, so I suspect that is already covered.
The problem with diving isn't the blood, it is the lungs, and later (when you resurface) the difference in solubility of various gasses in your tissues under different pressures.
The amount of, for example, nitrogen that can dissolve into your blood (again, for example) depends on the pressure. As the pressure goes up, more can dissolve. As the pressure goes down, less can dissolve, which means that when you surface, nitrogen dissolved in your body can suddenly reappear as a gas bubble which requires many times the volume that it took while dissolved. In a joint, or long muscle or fat, this can be painful. In an important artery or in your heart or other important organ (most of them), this can be fatal.
See that "Preview" button?
Standard procedure for killing test animals is nitrogen. Animal in chamber, nitrogen in chamber, oxygen out of chamber, animal dead. It's painless, and it doesn't cause any damage that might obscure important features.