Evaluation of a mathematical model of the acid‐base chemistry of blood

The objective of this study is to evaluate whether a mathematical model of acid‐base chemistry of blood [1,2] can simulate physiological situations such as the mixing of blood with different acid‐base status. To do so, two samples of venous blood from 21 normal subjects and 6 patients were equilibrated at different O 2 and CO 2 partial pressures and then mixed. The mathematical model was used to simulate this mixing and model‐simulated and measured values compared. Model simulations compared well with measured values with a small bias and standard deviation, within normal analytical variability, e.g. for normal subjects 0.000±0.006 pH, −0.06±0.11 kPa PCO 2 , −0.1±0.8 % SO 2 and −0.02±0.13 kPa PO 2 . This model is the first based on a mass‐balance, mass‐action formulation which can perform simulations of this type, including both hemoglobin buffering and the competitive binding of O 2 , CO 2 and H + on hemoglobin.