Comment by keithflower | Hacker News Reader

Comment by keithflower | Hacker News Reader

Oxygenation is only part of the problem, so I'm a little wary of the title "Injectable oxygen keeps people alive without breathing" [emphasis added].

EDIT: The actual paper's [2] title and abstract reads "Boosting Oxygenation During Acute Respiratory Failure - A new microparticle-based oxygen-delivery technology has been developed for short-term resuscitation of pulmonary function" [emphasis added].

The real problem is ultimately ventilation, or gas exchange at the alveoli. When it's impaired, both oxygenation and removal of carbon dioxide are affected. One result is respiratory acidosis. There is some literature[1] indicating the body can tolerate such acidosis better in the absence of hypoxemia so the cited idea may have merit as a stopgap measure, but I'm not sure how effective this scheme would be in near or complete absence of ventilation - like the example cited where the little girl's lungs are full of blood.

[1] - Acute Respiratory Distress Syndrome: Adjuncts to Lung-Protective Ventilation; http://www.medscape.com/viewarticle/410886_2

[2] - http://stm.sciencemag.org/content/4/140/140fs21.abstract?sid...

The bigger problem is oxygenation, at least in the short term. You can worry about ventilation later.

Lack of oxygen delivery from the blood will kill the brain sooner than the acidosis. Specifically, if this substance actually existed in a working form usable by humans, I could imagine its frequent use in pulseless electrical activity arrest. In PEA arrest, you fix the arrest by fixing the underlying problem; hypoxemia is one of the catch-all problems, and such a technology could permit you to intervene on hypoxemia even before you get airway control.

Yeah, big cause of PEA is hypoxia - delivery of this substance directly to an end organ's (brain) vasculature reliably and quickly (albeit in the absence of efficient circulation) is an interesting thought.

Right, this definitely seems like it's really to be used when oxygenation is the main problem. I'm guessing they'll worry about the acidosis after they get your heart and lungs working again. I'm not so sure about the suggestion in the article that this is going to be used by divers.

this question exposes my ignorance of how lungs work, but in a situation where the lungs were in good working order, would carbon dioxide build up in them (to be breathed out)?

Only until the partial pressure of CO2 was in equilibrium between the volume of air in the lungs and the the body tissues. It's like bailing out a boat -- it only works if you empty the bucket periodically.

could you "breathe" a small volume of something inert in and out, and have a CO2 scrubber?

Presumably, if your lungs were working well enough for that to be an option, you could just breathe air.

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