What is the fluid of choice for treating vomiting?

Fluid of Choice for Vomiting

Oral rehydration solution (ORS) is the first-line fluid of choice for treating vomiting in patients with mild to moderate dehydration, while isotonic intravenous fluids are indicated for severe dehydration or when oral rehydration fails. 1

Assessment of Hydration Status

Before selecting the appropriate fluid, assess the degree of dehydration:

• Mild dehydration (3-5%): Thirst, slightly dry mucous membranes, minimal electrolyte disturbances
• Moderate dehydration (6-9%): Decreased skin turgor, dry skin, higher risk of electrolyte abnormalities
• Severe dehydration (≥10%): Lethargy, prolonged skin retraction, cold extremities, severe electrolyte disturbances 2

Rehydration Protocol

Mild to Moderate Dehydration

• First choice: Low-osmolarity ORS 1

  • Infants and children: 50-100 mL/kg over 3-4 hours
  • Adolescents and adults: 2-4 L of ORS

• Replacement of ongoing losses:

  • For children <10 kg: 60-120 mL ORS for each vomiting episode (up to ~500 mL/day)
  • For children >10 kg: 120-240 mL ORS for each vomiting episode (up to ~1 L/day)
  • For adolescents and adults: Ad libitum, up to ~2 L/day 1

• Administration technique for persistent vomiting:

  • Start with small, frequent volumes (e.g., 5 mL every few minutes) 1
  • Gradually increase volume as tolerated
  • If oral intake is not tolerated, consider nasogastric administration of ORS 1

Severe Dehydration

• First choice: Intravenous isotonic crystalloids (Lactated Ringer's or normal saline) 1
  • Administer IV boluses (20 mL/kg) until pulse, perfusion, and mental status normalize
  • Once stabilized, transition to oral rehydration 1

Recommended ORS Products

• Commercially available ORS options:

  • Pedialyte (45 mEq/L sodium)
  • Ceralyte (higher sodium content)
  • Enfalac Lytren 1

• Avoid these fluids for rehydration:

  • Apple juice
  • Sports drinks (Gatorade)
  • Commercial soft drinks
  • Alcoholic beverages 1, 2

Special Considerations

For Older Adults

• Older adults with vomiting should be encouraged to drink preferred fluids (tea, coffee, water) 1
• For those who appear unwell or have measured serum osmolality >300 mOsm/kg, consider subcutaneous or intravenous fluids in parallel with oral intake 1

For Persistent Vomiting

• Consider nasogastric tube administration if oral intake is not tolerated 1
• In severe cases where antiemetics are needed, ondansetron may be considered (0.15 mg/kg IV or 0.2 mg/kg oral, maximum 4 mg) 3, 4

Common Pitfalls to Avoid

1. Don't delay rehydration - ORT can be initiated more quickly than IV therapy and is equally effective for mild to moderate dehydration 5

2. Don't assume vomiting is a contraindication to oral rehydration - Small, frequent volumes of ORS can still be effective 1, 6

3. Don't use inappropriate fluids - Regular sodas, fruit juices, and sports drinks have inappropriate electrolyte content and osmolarity that can worsen diarrhea and electrolyte imbalances 1, 2

4. Don't neglect ongoing losses - Continue to replace fluid losses as long as vomiting persists 1

5. Don't overlook the need for transition to oral rehydration - Even patients who initially require IV therapy should transition to oral rehydration once stabilized 1

By following this evidence-based approach to fluid selection and administration, you can effectively manage vomiting while minimizing complications related to dehydration and electrolyte imbalances.