1/θCO equations that show reasonable agreement

Formula for 1/θCO1/θCOθNO/θCO
Ideal Hb (14.6 g·dL−1)Ideal Hb (13.4 g·dL−1)Ideal Hb (14.6 g·dL−1)Ideal Hb (13.4 g·dL−1)
Derived in vivo
  Guénard et al. [16](0.0062·PAO2+1.16)·(ideal Hb÷measured Hb)1.7801.9398.0108.727
Derived in vitro
  Forster [4] α=∞, pH=7.4(0.0041·PAO2+1.3)·(ideal Hb÷measured Hb)1.7101.8637.6958.384
  Roughton and Forster [11]  α=1.5, pH=8.0(0.0058·PAO2+1.0)·(ideal Hb÷measured Hb)1.5801.7217.1107.747
  Holland [28] α=1.5(0.0065·PAO2+1.08)·(ideal Hb÷measured Hb)1.7301.8857.7858.482
  • Numbers given are for the following standards: alveolar oxygen tension (PAO2) 100 mmHg and specific conductance in the blood for nitric oxide (θNO) 4.5 mL NO· (mL blood·min·mmHg)−1 and thus 1/θNO=0.222, from [14, 29]. θCO: specific conductance in the blood for carbon monoxide; Hb: haemoglobin; α: the ratio of permeability of the red cell membrane to that of the red cell interior.