Non-SI unit for pressure; mmHg ≈ 133.322 Pa. This old unit is not recognized by
CIPM or
ISO, but it is used for blood pressure.
Source:
PAC, 1996, 68, 957. 'Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)' on page 981 (https://doi.org/10.1351/pac199668040957)