What is the recommended IV fluid dosage for dehydration?

IV Fluid Dosage for Dehydration

The recommended IV fluid dosage for dehydration varies based on severity, with mild to moderate dehydration requiring 50-100 mL/kg over 2-4 hours, while severe dehydration requires immediate boluses of 20-30 mL/kg of isotonic crystalloid solution. 1, 2, 3

Assessment of Dehydration Severity

• Dehydration severity should be determined through physical examination, with mild dehydration (3-5% fluid deficit) characterized by increased thirst and slightly dry mucous membranes 1
• Moderate dehydration (6-9% fluid deficit) presents with loss of skin turgor and dry mucous membranes 1, 2
• Severe dehydration (≥10% fluid deficit) manifests as severe lethargy or altered consciousness and prolonged skin tenting 1
• Rapid, deep breathing, prolonged skin retraction time, and decreased perfusion are more reliable indicators of dehydration than sunken fontanelle or absence of tears 1, 2

IV Fluid Dosage by Severity

Mild Dehydration (3-5% fluid deficit)

• Oral rehydration is preferred with 50 mL/kg ORS over 2-4 hours 1, 2
• If IV therapy is necessary, administer isotonic crystalloid at 50 mL/kg over 2-4 hours 1

Moderate Dehydration (6-9% fluid deficit)

• Administer 100 mL/kg ORS over 2-4 hours if oral rehydration is possible 1, 2
• If IV therapy is required, administer isotonic crystalloid at 100 mL/kg over 2-4 hours 2
• Rapid IV rehydration with 20-30 mL/kg isotonic crystalloid over 1-2 hours has been shown effective in correcting dehydration and resolving vomiting in children 3

Severe Dehydration (≥10% fluid deficit)

• Constitutes a medical emergency requiring immediate IV rehydration 1
• Administer boluses of Ringer's lactate solution or normal saline at 20-30 mL/kg 1, 4
• Reassess after each bolus and continue until clinical improvement is observed 1

Choice of IV Fluid

• Ringer's lactate is the preferred IV solution for severe dehydration, though normal saline may also be used 4, 5
• Both NS, lactated Ringer's, and Plasmalyte can be used safely, but NS may cause mild acidosis which could be significant in patients with underlying metabolic disturbances 5
• For patients with cholera or severe diarrheal illness, Ringer's lactate is particularly recommended 4

Monitoring and Adjustments

• Reassess hydration status after 3-4 hours of treatment and adjust therapy accordingly 6
• Monitor intake, outputs, and hydration status closely for all patients 4
• For ongoing losses, replace each diarrheal stool with 10 mL/kg of ORS and each episode of emesis with 2 mL/kg of ORS 2
• Patients with serum bicarbonate ≤13 mEq/L may require more prolonged IV fluid therapy 3

Special Considerations

• Elderly patients are more susceptible to dehydration and may require closer monitoring 7
• Continue feeding as appropriate during rehydration; avoid "resting the bowel" through fasting 6, 1
• Breastfed infants should continue nursing on demand throughout rehydration 6, 2
• Bottle-fed infants should use full-strength, lactose-free, or lactose-reduced formulas immediately upon rehydration 1, 2

Transition to Oral Hydration

• After IV rehydration, test tolerance of oral fluids with 1-3 ounces of clear fluid 3
• If oral fluids are tolerated, transition to oral rehydration and maintenance therapy 3
• If vomiting persists after IV rehydration, continued IV therapy may be necessary 3