What fluids are recommended for managing multiple episodes of vomiting?

Oral Rehydration Solution (ORS) is the Recommended Fluid for Multiple Episodes of Vomiting

For patients with multiple episodes of vomiting, low-osmolarity oral rehydration solution (ORS) is the first-line fluid therapy, administered in small, frequent volumes (5-10 mL every 1-2 minutes) with gradual increases as tolerated. 1, 2

Initial Fluid Management Strategy

For Mild to Moderate Dehydration

• Administer 50-100 mL/kg of low-osmolarity ORS over 3-4 hours 1, 2
• In children <10 kg: give 60-120 mL ORS after each vomiting episode (up to ~500 mL/day) 1
• In children >10 kg: give 120-240 mL ORS after each vomiting episode (up to ~1 L/day) 1, 2
• In adults: administer ad libitum, up to ~2 L/day 1

Critical Technique for Vomiting Patients

• Give small volumes (5-10 mL) via spoon or syringe every 1-2 minutes, then gradually increase as tolerated 1, 3
• Most fluid is retained despite apparent vomiting—continue ORS after waiting 10 minutes 4
• Avoid allowing thirsty patients to drink large volumes rapidly from a cup or bottle, as this worsens vomiting 1

When to Use Alternative Routes

Nasogastric Administration

• Consider nasogastric ORS at 15 mL/kg/hour for patients who cannot tolerate oral intake but have normal mental status and are not in shock 1, 2
• This approach is as safe and efficacious as intravenous therapy for moderate dehydration 5

Intravenous Fluids

• Use isotonic crystalloid (lactated Ringer's or normal saline) at 20 mL/kg boluses for: 1, 3
  • Severe dehydration with shock or altered mental status
  • Failure of ORS therapy after adequate trial
  • Intestinal ileus (absent bowel sounds)
• Continue IV therapy until pulse, perfusion, and mental status normalize, then transition to ORS 1, 2

Specific ORS Formulation

Recommended Composition

• Use low-osmolarity ORS (osmolarity <250 mmol/L, typically 245 mosm/L) for all age groups and causes of vomiting 1, 2
• Commercial products include Pedialyte, CeraLyte, and Enfalac Lytren 1

Fluids to AVOID

• Never use apple juice, Gatorade, sports drinks, or soft drinks—these have inappropriate electrolyte content and high osmolality that can worsen dehydration 1, 2

Adjunctive Management

Antiemetic Use

• Ondansetron (0.15-0.2 mg/kg, maximum 4 mg) may be considered for persistent vomiting preventing oral intake, but only after initiating ORS therapy 6
• The FDA label supports ondansetron use for vomiting, though it is primarily studied for chemotherapy-induced nausea 7
• Avoid other antiemetics like chlorpromazine due to sedation that interferes with ORS continuation 4

Feeding During Illness

• Continue breastfeeding throughout the illness 1, 3
• Resume age-appropriate normal diet during or immediately after rehydration is complete 1, 3
• Do not withhold food or use diluted formulas 1

Monitoring and Reassessment

• Reassess hydration status after 3-4 hours of ORS therapy 1, 2
• If still dehydrated, continue supervised ORS in a clinical setting 1
• Monitor for warning signs requiring IV therapy: inability to tolerate any oral fluids, worsening dehydration, altered mental status, or serum bicarbonate ≤13 mEq/L 8

Common Pitfalls to Avoid

• Do not delay ORS administration while waiting for laboratory results—most routine testing is unnecessary 5
• Do not restrict fluids or delay feeding until vomiting stops 1, 2
• Do not use antimotility agents (loperamide) in children or when inflammatory diarrhea is suspected 3
• Do not give up on ORS too quickly—greater than 90% of vomiting patients can be successfully rehydrated orally with proper technique 1

The evidence strongly supports that vomiting typically diminishes or stops within 1-2 hours of starting properly administered ORS, and most fluid is retained despite apparent vomiting 4. The reduced osmolarity formulation decreases the need for unscheduled IV therapy by 33% compared to standard WHO ORS 9.