In fresh water aspiration, the hypotonic water is easily absorbed via the lung parenchyma, which can result in hemodilution, hyponatremia and fluid overload. Red blood cells swell and lyse, causing hyperkalemia and hemoglobinuria. Salt water should cause the reverse, particularly hypernatremia and hemoconcentration. However, in both fresh and salt water drowning, pulmonary edema is a potential consequence. Pulmonary edema seems to be more common in fresh water aspiration.
Bacterial pneumonia can worsen the effects, as can aspiration of stomach contents.
Gradual cooling in icy water induces predictable physiologic changes , with increased respiratory rates and shivering maintaining metabolic activity. In rare instances, one might survive intact after prolonged submersion in icy water. As a rule, however, prolonged submersion, even in icy water, is likely to result in permanent neurologic damage or death. Damage to other organs Failure of the cardiovascular system is most likely a result of hypoxic-ischemic damage. The same can be said of the renal failure, coagulopathy and gastrointestinal dysfunction that may accompany the respiratory failure from drowning.