Which of the following are respiratory and blood chemistry dysfunctions associated with the in-halation of freshwater?

1. Rapid depletion of alveolar surfactant
2. Direct damage to the alveolar-capillary membrane
3. Acute neurogenic pulmonary edema
4. Rapid loss of circulating volume into the alveolar space across the injured alveolar capillary membrane may cause hemoconcentration, hypernatremia, and hypoalbuminemia
a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: A
1. Inhalation of freshwater
a. Inhalation of freshwater and its effects on the respiratory system. Inhalation of freshwater rap-idly depletes alveolar surfactant, leading to ventilation/perfusion mismatch. Inhaled water is quickly absorbed into the vascular system from the alveolar space by osmosis, causing alveolar collapse and worsening shunt and hypoxia. Additionally, in the setting of inhaled freshwater, acute neurogenic pulmonary edema due to cerebral hypoxia has been shown to worsen alveolar flooding. However, if hypoxia is reversed, normal pulmonary function can be quickly restored.
b. The effects of inhalation of freshwater on other organs. If a large volume of freshwater is in-haled, it is rapidly absorbed into the circulation, leading to electrolyte imbalance. Hyponatrem ia can lead to seizures, especially in pediatric patients. Additionally, diluted plasma causes water to rapidly enter into erythrocytes by osmosis, causing hemolysis. The resulting hyperkalemia and hyponatremia can cause ventricular fibrillation, and the liberation of hemoglobin into the plasma can precipitate acute renal failure.