When it comes to imagining the future, the sky is really the limit, considering all of the technology we now have at our fingertips.

And since we know human embryos and fetuses “breathe” liquid rich in oxygen, some wonder whether or not we could ever recreate this environment outside the womb.

Science actually says this is possible – both in theory and in clinical trials.

In fact, we already use a form of it, called partial liquid ventilation, to provide oxygen to patients during mechanical ventilation.

Medical professionals use oxygen-rich liquids such as a perfluorocarbon (PFC), which can support pulmonary gas exchange.

Other than in a medical setting, liquid breathing could benefit deep sea divers. It would make it easier to pressurize and reduce or eliminate the concerns of decompression sickness (the bends).

The concept has been tried out in mice and cats, some of which were able to survive the process for weeks.

Unfortunately, no one has figured out how to allow them to return to regular breathing, so all of the subjects eventually expired.

Another issue is that even though enough oxygen reached the bloodstream, it was harder for the body to eliminate carbon dioxide.

In partial liquid ventilation, the amount of liquid is small and eliminated via evaporation. 

In a real-life scenario, filling your lungs with liquid and then expelling it would not only be very unpleasant, but hard on your lungs, which are not used to the work it takes to move denser liquids.

Some have suggested we could address the problem of clearing carbon dioxide by attaching a device directly to the bloodstream. It would scrub carbon dioxide through a vein in your leg.

Scientists are interested in the possibility for astronauts, since they are looking for ways around our inability to withstand massive G forces for more than a few seconds.

If an astronaut could be suspended in liquid, the G force would be distributed over the entire surface – this could be an ability to withstand forces up to 24 G.

This might sound like science fiction, but with the right motivation, it seems like a problem that could be solved.

At least for specific people in specific scenarios.

The rest of us don’t have to worry about breathing water. For now.

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