Fig. (2).

The same baseline condition (A), modified by different combinations of G_A, Na⁺ lost and volume lost, can produce different clinical presentations. The ratio between _PNa⁺_G and _PNa⁺_M can help the physician to estimate whether volume losses prevail over Na⁺ losses (D), Na⁺ losses prevail over volume losses (G) or the two actually balance and the reduction in _PNa⁺ can be approximated to that exclusively produced by water shift (E, F). _PNa⁺_G has been calculated with the formulas reported in Table 2.