Figure 1:Independent variables influencing acid-base balance according to the simplified Stewart approach. SID is Strong Ion Difference, PCO2 refers to the partial pressure of carbon dioxide and Atot corresponds to the level of non-volatile weak buffers (weak acids/bases) in the extracellular fluid
Figure 3:Figure indicating the addition of extra anionic charge (as might be caused by the addition of molecules such as lactate) to the extracellular fluid
Figure 4:Figure indicates the consequence of the imbalance induced by the addition of extra anionic charge to the extracellular fluid and the resultant increase in level of hydrogen ions, re-establishing electrostatic balance (Figure 5, below), but creating a metabolic acidosis