3. isotonic dehydration ① water loss≈ sodium loss 2 serum sodium=130-150mmol/L plasma osmotic pressure: 280-310mOsm/L 1)cause and pathogenesis O vomiting; diarrhea; gastrointestinal suction biliary fistula; intestinal fistula ascitic fluid; pleural effusion3. isotonic dehydration ① water loss ≈ sodium loss ② serum sodium = 130-150mmol/L ③ plasma osmotic pressure:280- 310mOsm/L 1) cause and pathogenesis ① vomiting; diarrhea; gastrointestinal suction; biliary fistula; intestinal fistula ② ascitic fluid; pleural effusion