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Unit "Volume per pressure" missing?


could anyone point me into the direction of a unit that represents “volume per pressure” (as can be found in lung compliance, for example).

I’ve found nothing in Athena and this forum, unfortunately. Is there such a thing as a “volume per pressure” unit (ml/mbar, ml/cmH2O, ml/bar, L/bar, …)?

Thank you so much,

@dlaxar, unfortunately we also can’t find such units in current version of vocabularies in Athena. Please, clarify, which specific volume per pressure units do you need, and we add this concepts in UCUM Vocabulary.

Thank you for getting back to me so quickly.

The most common ones I can think of are:

  • ml/cmH2O (although I’d suggest to at use ISO-Units and go with ml/mbar and L/bar) for lung compliance
  • mbar/L for the reciprocal lung elastance (pressure per volume)

On the other side, mbar is not a standard unit as of now. If we used ISO Units I’d suggest also adding the appropriate component units, i.e. adding mbar.

If there is anything I can do to help, please let me know.


Hello, @dlaxar

Well, in a rush of vocabulary refreshes, we haven’t tagged you here!


These units have been here for a while

If you still need something else, write here:

Hi @zhuk,

thanks for getting back to me. We’ve already implemented these new units into our ETL.