"Ventilator Blues" marks the first and only time guitarist Mick Taylor would be given credit alongside regular Stones scribes Mick Jagger and Keith Richards. While his exact amount of input is unknown, Taylor's contribution of the song's opening slide riff is considered the main reason he was given the credit, as it drives the song.
"Lumbering" is I guess the word you'd use to describe the song. The jerky rhythm always sounded like one of Tom Waits's existential blues recordings from Bone Machine.
There really isn't anything notable about the song apart from Jagger, who is in full Mick Jagger mode, double-tracked for even more Jaggery goodness.