The key difference lies in the tonicity of the inhaled water relative to blood, which drives opposite shifts of fluid across the alveolar membrane.
| Feature | Freshwater Drowning | Saltwater Drowning |
|---|---|---|
| Nature of water | Hypotonic | Hypertonic |
| Blood volume | Increased (hemodilution) | Decreased (hemoconcentration) |
| RBC changes | Hemolysis | Shrinkage (crenation) |
| Serum electrolytes | Decreased sodium and chloride | Increased sodium and chloride |
| Cause of death | Ventricular fibrillation | Asphyxia, pulmonary edema |
| Lung weight | Relatively less | Heavier due to edema |