The most common and most likely answer to this crossword clue is the 7 letter word TRACHEA
I've seen this crossword clue in The Times
T
R
A
C
H
E
A
More clues leading to the result TRACHEA
- Contribution towards ultra-cheap passage
- Drawing back, holding long tube
- Body part extra cheap if not complete
- Technique set up to restrict pain in part of body
- What to carry back with a vital pipe [7]
- Hydrogen in tiny amount over area where air passes
- Pain in most of mouth and windpipe
- Some electricity through heart shocked part of body
- Pipe that splits in two inside of chest
- Tube of paintings knocked over by red American
Buddy explains!

The straight part
We know that "vital pipe" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vital pipe = trachea.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TRACHEA mean?
TRACHEA noun- A thin-walled, cartilaginous tube connecting the larynx to the bronchi; the windpipe.
- Xylem vessel.
- One of the cuticle-lined primary tubes in the respiratory system of an insect, which extend throughout its body.