Fluid replacement for short bowel syndrome
People who have a short bowel with a stoma can develop dehydration associated with a high volume of fluid output via the stoma. The use of oral rehydration, intravenous rehydration and parenteral nutrition should be individualised. In general, intravenous rehydration or parenteral nutrition should be considered in patients if their stoma output is more than 2 L/day.
Due to changes in the physiology of absorption in patients with short bowel syndrome, increased consumption of hypotonic fluids (eg water) or hypertonic fluids (eg fruit juice) can exacerbate dehydration by increasing stomal output.
Management of fluid loss and dehydration involves restriction of hypotonic and hypertonic fluids, and rehydration with a solution containing 90 to 120 mmol/L of sodium and 90 to 110 mmol/L of glucose.
An example of an appropriate oral fluid replacement solution is St Mark’s mixture, which can be prepared by dissolving the following in 1 litre of tap water:
- 6 teaspoons (20 g) glucose powder
- 1 teaspoon (3.5 g) salt
- half a teaspoon (2.5 g) sodium bicarbonate or sodium citrate.
This solution may be prepared by the patient or a hospital pharmacy. Palatability can be improved by adding a small amount of cordial, or chilling the solution in the refrigerator.
Proprietary oral rehydration solutions (eg Gastrolyte, Hydralyte) contain a lower concentration of sodium (60 mmol/L or less) than required for a person with short bowel syndrome. However, proprietary solutions can be modified by adding 1 teaspoon (3.5 g) of salt to 1 litre of prepared solution. This may be used as an alternative to St Mark’s mixture.
The total daily sodium requirement depends on the volume of stomal output (about 100 mmol of sodium is lost in every litre of effluent) in addition to the daily maintenance sodium requirement.
Monitor the patient’s plasma electrolyte concentrations and kidney function. Ongoing assessment by a specialist team is required.