B Appendix 2 - rules of thumb

B.1 pH and [H+]

[H+] = 80 minus the first two digits of pH after the decimal point.

PaCO2: 1 kPa = 7.5 mmHg.

B.2 Urine specific gravity and UOsm

300 mOsm per 0.01 units of SG.

Therefore:

  • SG 1.010 = 300 mOsm
  • SG 1.020 = 600 mOsm
  • SG 1.030 = 900 mOsm

Caution after radiocontrast.