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Units of Measure

Phil B. Fontanarosa

and Stacy Christiansen

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date: 21 January 2020

Blood pressure and intraocular pressure are reported in millimeters of mercury (mm Hg); cerebrospinal fluid pressure is reported as centimeters of water (cm H2O). The pascal (newton per square meter [N/m2]) is the recommended SI unit for pressure but generally is not used for reporting these common physiologic pressure measurements. Partial pressure of gases (eg, of oxygen and carbon dioxide) may be reported as millimeters of mercury (mm Hg) or as kilopascals (kPa). (See also , Nomenclature, Pulmonary, Respiratory, and Blood Gas Terminology.)

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