[ars]

You could wash one lung at a time. Or use extracorporeal membrane oxygenation.

Water in an of itself won't hurt lungs as long as the patient gets enough oxygen.

[kleim]

"Water in an of itself won't hurt lungs"

Yes it does: http://en.wikipedia.org/wiki/Drowning#Secondary_drowning

If you ever get saved from near drowning, you are still not safe.

[FreeFull]

I imagine you would have to use saline rather than plain water to avoid the lung cells bursting due to osmosis.