Cut out

• The story even features a sword technique called "the Flute of the Fallen Tiger" that creates wounds that whistle as they bleed out, meaning that people in the story not only have absurdly high-pressure blood, but also a fair amount of gas trapped inside their blood vessels as well.

from High Pressure Blood. I suspect that whoever wrote that misinterpreted what was happening; the referred-to one-shot scene implies that a fatal neck wound has also nicked the windpipe in such a way that the air passing through the windpipe whistles as it escapes the cut. Not prepared to testify as to the medical possibility of this, but it was in no way implied to be the blood vessels themselves "singing".