What is the optimal sodium concentration of an oral rehydration solution for patients with short bowel syndrome?

• A. 40 mmol/L
• B. 140 mmol/L
• C. 90 mmol/L
• D. 190 mmol/L

Answer: (C)

Focus on replacing the mix of fluids and electrolytes the gut loses while maximizing water absorption through the sodium-glucose transport mechanism. An oral rehydration solution with about 90 mmol/L sodium is near isotonic and provides enough sodium to match typical diarrheal losses seen in short bowel syndrome, supporting efficient water uptake without pushing serum sodium too high. If the sodium were much higher, like 140 mmol/L or more, there’s a risk of hypernatremia and increased osmolality; if it were too low, like 40 mmol/L, it wouldn’t adequately replace losses. A concentration around 90 mmol/L strikes the right balance for SBS patients.