Previous

APPENDIX: Système International

3199
3200
3201

The following information on Système International (SI) units and factors for conversion between SI and older conventional units is provided for the convenience of readers and authors. Reprints of these tables are available on request from The Canadian Anaesthetists' Society Journal, 178 St. George Street, Toronto, Canada, M5R 2M7. *


Basic SI units
Physical Quantity Name Symbol
Length Meter m
Mass Kilogram kg
Time Second * s
Electric current Ampere A
Thermodynamic temperature Kelvin K
Luminous intensity Candela cd
Amount of substance Mole mol
*Minute (min), hour (h) and day (d) will remain in use although they are not official SI units.




Prefixes for SI units
Factor Name Symbol Factor Name Symbol
1018 Exa- E 10-18 Atto- a
1015 Peta- P 10-15 Femto- f
1012 Tera- T 10-12 Pico- p
109 Giga- G 10-9 Nano- n
106 Mega- M 10-6 Micro- μ
103 Kilo- k 10-3 Milli- m
102 Hecto- h 10-2 Centi- c
101 Deca- da 10-1 Deci- d


Derived SI units
Quantity SI Unit Symbol Expression in Terms of SI Base Units or Derived Units
Frequency Hertz Hz 1 Hz = 1 cycle/s (1 s-1 )
Force Newton N 1 N = 1 kg · m/s2 (1 kg · mps-2 )
Work, energy, quantity of heat Joule J 1 J = 1 N · m
Power Watt W 1 W = 1 J/s (1 J · s-1 )
Quantity of electricity Coulomb C 1 C = 1 A · s
Electric potential, potential difference, tension, electromotive force Volt V 1 V = 1 W/A (1 W · A-1 )
Electric capacitance Farad F 1 F = 1 A · s/V (1 A · s · V-1 )
Electric resistance Ohm Ω 1 Ω = 1 V/A (1 V · A-1 )
Flux of magnetic induction, magnetic flux Weber Wb 1 Wb = 1 V · s
Magnetic flux density, magnetic induction Tesla T 1 T = 1 Wb/m2 (1 Wb · m-2 )
Inductance Henry H 1 H = 1 V · s/A (1 V · s · A-1 )
Pressure Pascal Pa 1 Pa = 1 N/m2 (1 N · m-2 )



     = 1 kg/m · s2 (1 kg · m-1 · s-2 )
The liter (10-3 m3 = dm3 ), though not official, will remain in use as a unit of volume as also will the dyne (dyn) as a unit of force (1 dyn = 10-5 N).

*Reprinted from The Canadian Anaesthetists' Society Journal.
3202
Conversion Factors
SI Unit Old Unit Old to SI (Exact) SI to Old (Approx.)
kPa mm Hg * 0.133 7.5
kPa 1 standard atmosphere † (approx. 1 Bar) 101.3 0.01
kPa cm H2 O 0.0981 10
kPa lbs/sq in 6.89 0.145
*e.g., systolic BP of 120 mm Hg = 16 kPa and diastolic BP of 80 mm Hg = 11 kPa.
 †760 mm Hg.




Blood chemistry, units and conversion factors



Conversion Factors
Measurement SI Unit Old Unit Old to SI (Exact) SI to Old (Approx.)
Blood
Acid-Base



  PCO2 kPa mg Hg 0.133 7.5
  PO2 kPa mm Hg 0.133 7.5
  Standard bicarbonate mmol/liter mEq/liter Numerically equivalent
  Base excess mmol/liter mEq/liter Numerically equivalent
  Glucose mmol/liter mg/100 mL 0.0555 18
Plasma



  Sodium mmol/liter mEq/liter Numerically equivalent
  Potassium mmol/liter mEq/liter Numerically equivalent
  Magnesium mmol/liter mEq/liter 0.5 2
  Chloride mmol/liter mEq/liter Numerically equivalent
  Phosphate (inorganic) mmol/liter mEq/liter 0.323 3.0
  Creatinine µmol/liter mg/100 mL 88.4 0.01
  Urea mmol/liter mg/100 mL 0.166 6.0
Serum



  Calcium mmol/liter mg/100 mL 0.25 4.0
  Iron µmol/liter µg/100 mol 0.179 5.6
  Bilirubin µmol/liter mg/100 mol 17.1 0.06
  Cholesterol mmol/liter mg/100 mL 0.0259 39
Total Proteins g/liter g/100 mL 10.0 0.1
  Albumin g/liter g/100 mL 10.0 0.1
  Globulin g/liter g/100 mL 10.0 0.1


Biochemical content of other body fluids



Conversion Factors
Measurement SI Unit Old Unit Old to SI (Exact) SI to Old (Approx.)
Urine
Calcium mmol/24 h mg/24 h 0.025 40
Creatinine mmol/24 h mg/24 h 0.00884 113
Potassium mmol/liter mEq/liter Numerically equivalent
Sodium mmol/liter mEq/liter Numerically equivalent
Cerebrospinal Fluid
Protein g/liter mg/100mL 0.01 100
Glucose mmol/liter mg/100mL 0.0555 18


Hematology



Conversion Factors
Measurement SI Unit Old Unit Old to SI SI to Old
Hemoglobin (Hb) g/dL g/100 mL Numerically equivalent
Packed cell volume No unit * Percent 0.01 100
Mean cell Hb conc. g/dL Percent Numerically equivalent
Mean cell Hb pg µµg Numerically equivalent
Red cell count Cells/liter Cells/mm3 106 10-6
White cell count Cells/liter Cells/mm3 106 10-6
Reticulocytes Percent Percent Numerically equivalent
Platelets Cells/liter Cells/mm3 106 10-6
*Expressed as decimal fraction, e.g., normal adult male value 0.40 to 0.54.




pH and nmol/liter of H* activity
pH nmol/liter
6.80 158
6.90 126
7.00 100
7.10  79
7.20  63
7.25  56
7.30  50
7.35  45
7.40  40
7.45  36
7.50  32
7.55  28
7.60  25
7.70  20

Previous