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Oral fluid therapy is effective, safe, convenient, and inexpensive compared with IV therapy. It should be used for children with mild to moderate dehydration who are accepting fluids orally unless prohibited by copious vomiting or underlying disorders (eg, surgical abdomen, intestinal obstruction).
Solutions:
Oral rehydration solution should contain complex carbohydrate or 2% glucose and 50 to 90 mEq/L of Na. Sports drinks, sodas, juices, and similar drinks do not meet these criteria and should not be used. They generally have too little Na and too much carbohydrate to take advantage of Na/glucose cotransport, and the osmotic effect of the excess carbohydrate may result in additional fluid loss.
Oral rehydration solution (ORS) is recommended by the WHO and is widely available in the US without prescription. Most solutions come as powders that are mixed with tap water. Premixed solutions also are available in most pharmacies and supermarkets. An ORS packet is dissolved in 1 L of water to produce a solution containing (in mmol/L) Na 90, K 20, Cl 80, citrate 10, and glucose 111 (standard WHO ORS) or Na 75, K 20, Cl 65, citrate 10, and glucose 75 (WHO reduced-osmolarity ORS). It can also be made manually by adding 1 L of water to 3.5 g NaCl, 2.9 g trisodium citrate (or 2.5 g NaHCO3), 1.5 g KCL, and 20 g glucose. ORS is effective in patients with dehydration regardless of age, cause, or type of electrolyte imbalance (hyponatremia, hypernatremia, or isonatremia) as long as their kidneys are functioning adequately. After rehydration, this solution must be replaced by a lower-Na fluid to avoid hypernatremia.
If specific rehydration solutions (powders or premixed) are unavailable, some clinicians advise caretakers to prepare a homemade solution using sugar and table salt. However, even with written instructions (and in some cases, dispensing 2 color-coded scoops), errors in preparation have at times caused fatal hypernatremia. Therefore, if specific rehydration solutions are unavailable, infants with mild to moderate dehydration should be continued on breast milk or formula, but the threshold for using IV hydration in those with moderate dehydration should be lower. Clinicians in practice situations where patients may be unable to obtain appropriate ORS on their own should explore alternative means of making the solution available.
Administration:
Generally, 50 mL/kg is given over 4 h for mild dehydration and 100 mL/kg for moderate. For each diarrheal stool, an additional 10 mL/kg (up to 240 mL) is given. After 4 h, the patient is reassessed. If signs of dehydration persist, the same volume is repeated. Patients with cholera may require many liters of fluid/day.
Vomiting usually should not deter oral rehydration (unless there is bowel obstruction or other contraindication). Small, frequent amounts are used, starting with 5 mL q 5 min and increasing gradually as tolerated.
Once the deficit has been replaced, an oral maintenance solution containing less Na should be used. Children should eat an age-appropriate diet as soon as they have been rehydrated and are not vomiting. Infants may resume breastfeeding or formula. Infants with diarrhea who develop signs or symptoms of malabsorption (see Malabsorption Syndromes) should be given lactose-free formula.
Last full review/revision May 2007 by Kenneth B. Roberts, MD
Content last modified May 2007
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