1/21 Acid–base interpretation often feels like a maze. But there’s a simple way to make sense of it at the bedside. It starts with pH, strong ions, and base excess.

2/21 First: what is pH? pH = the concentration of hydrogen ions, which come from water splitting into H⁺ and OH⁻. Anything that changes how much water dissociates changes pH.

3/21 Ions drive this process. 👉 Strong ions (Na⁺, K⁺, Cl⁻, lactate⁻) fully dissociate, their charges are fixed. 👉 Weak acids (albumin, phosphate, bicarbonate) only partly dissociate and buffer H⁺.