Oral Rehydration Therapy

For children with mild to moderate dehydration, ORT is the preferred therapy. It is effective because of the fact that GI sodium absorption (and water) is via coupled sodium/glucose transport. Water absorption is maximal at a glucose concentration of 2.5% (higher glucose concentrations lead to a high intestinal osmotic load and worsening diarrhea)

CHLA Board Review 2005

Table 3. Composition of Appropriate Oral Rehydration Solutions

Solution CHO*, g/dL Na, mEq/L K, mEq/L Base, mEq/L Osmolality
Pedialyte 2.5 45 20 30 250
Infalyte 3 50 25 30 200
Rehydralyte 2.5 75 20 30 310
WHO/UNICEF 2 90 20 30 310

World Health Organization/United Nations Children's Fund

All of the commercially available rehydration fluids are acceptable for oral rehydration therapy (ORT). They contain 2-3 g/dL of glucose, 45-90 mEq/L of sodium, 30 mEq/L of base, and 20-25 mEq/L of potassium. Osmolality is 200-310 mOsm/L.

Table 4. Composition of Inappropriate Oral Rehydration Solutions

Solution CHO, g/dL Na, mEq/L K, mEq/L Base, mEq/L Osmolality
Apple juice 12 0.4 26 0 700
Ginger ale 9 3.5 0.1 3.6 565
Milk 4.9 22 36 30 260
Chicken broth 0 2 3 3 330

Traditional clear fluids are not appropriate for ORT. Many contain excessive concentrations of CHO and low concentrations of sodium. The inappropriate glucose-to-sodium ratio impairs water absorption, and the large osmotic load creates an osmotic diarrhea, further worsening the degree of dehydration.

Vomiting is generally not a contraindication to ORT. If evidence of bowel obstruction, ileus, or acute abdomen exists, then intravenous rehydration is indicated.

The oral rehydration solution should be administered in small volumes very frequently to minimize gastric distention and reflex vomiting. Generally, 5 mL of oral rehydration solution every minute is well tolerated. Hourly intake and output should be recorded by the caregiver. As the child becomes rehydrated, vomiting often decreases and larger fluid volumes may be used.

If vomiting persists, infusion of oral rehydration solution via a nasogastric tube may be temporarily used to achieve rehydration. Intravenous fluid administration (20-30 mL/kg of isotonic sodium chloride solution over 1-2 h) may also be used until oral rehydration is tolerated.

E-medicine: Dehydration 9/17/2004: http://www.emedicine.com/PED/topic556.htm