TABLE 1
FROM:
Stewart and beyond: New models of acid-base balance
Howard E Corey
BACK TO ARTICLETable 1. Comparison of the base excess, Stewart, and ion equilibrium models of acid-base balance
| Base excess | Stewart | Ion equilibrium | |
|---|---|---|---|
| Acids and bases | Bronsted-Lowry | Arrhenius-like | Bronsted-Lowry |
| Measures magnitude | Yes | Yes | Yes |
| Explains mechanism | Noa | Yes | Noa |
| Classifies disorder | Yes | Yes | Yes |
| Independent variables | Base excess, [ ], PCO
2
| [SID], [ATot], PCO 2 | Anyb |
| Intracellular buffers | Yes | No | Not as currently developed |
| Noncarbonate buffers | Noc | Yes | Yes |
| Advantages | Familiar and relatively simple | Comprehensive | Comprehensive and flexible |
| Disadvantages | Requires "plug-ins" such as anion gap and  | Nonstandard definition of acids and bases | No new mechanistic information |
a Unless anion-gap is used
b May use traditional or Stewart set of variables
c Unless Van Slyke's (
base/pH) is used or base excess measured by titration
