What is the best approach to managing vomiting in pediatric patients?

Approach to Vomiting in Children

The cornerstone of managing vomiting in children is oral rehydration using small, frequent volumes (5 mL every 1-2 minutes) administered via spoon or syringe, which achieves >90% success in overcoming vomiting and preventing dehydration. 1

Initial Assessment and Hydration Status Classification

Immediately assess for red flag signs that require urgent intervention or surgical consultation: 1, 2

• Bilious or bloody vomiting
• Signs of shock (prolonged capillary refill >3 seconds, weak pulse, cool extremities)
• Altered mental status or lethargy
• Severe dehydration (≥10% fluid deficit)

Classify dehydration severity using clinical examination: 1, 2

• Mild dehydration (3-5% deficit): Slightly dry mucous membranes, normal vital signs, increased thirst 2
• Moderate dehydration (6-9% deficit): Decreased skin turgor, sunken eyes, decreased urine output, mild tachycardia 2
• Severe dehydration (≥10% deficit): Markedly decreased skin turgor with prolonged tenting, sunken fontanelle (infants), lethargy, weak pulse, prolonged capillary refill >3 seconds 2

Important clinical pearl: Capillary refill time is the most reliable predictor of dehydration in children and should be prioritized over less reliable signs like sunken fontanelle or absent tears. 1, 3

Rehydration Protocol Based on Severity

Severe Dehydration (≥10% deficit)

This is a medical emergency requiring immediate IV resuscitation: 1, 2

• Administer 20 mL/kg boluses of Ringer's lactate or normal saline IV immediately
• Repeat boluses until pulse, perfusion, and mental status normalize
• Once circulation is restored, transition to oral rehydration solution (ORS) for remaining deficit replacement

Moderate Dehydration (6-9% deficit)

Administer 100 mL/kg of ORS over 2-4 hours using the small-volume technique described below. 1, 2

Mild Dehydration (3-5% deficit)

Administer 50 mL/kg of ORS over 2-4 hours using the small-volume technique. 1, 2

The Small-Volume Technique for Overcoming Vomiting

This is the critical technique that makes oral rehydration successful even in vomiting children: 4, 1

• Start with 5 mL every 1-2 minutes using a spoon or syringe
• Provide close supervision to guarantee gradual progression
• Simultaneous correction of dehydration lessens the frequency of vomiting
• This approach achieves >90% success rate in vomiting children 1

Common pitfall to avoid: Do not give large volumes of fluid at once, as this will perpetuate vomiting. The small, frequent approach is essential for success. 4

Ongoing Loss Replacement

Replace fluid losses as they occur: 1, 2

• Give 10 mL/kg of ORS for each watery stool 1, 2
• Give 2 mL/kg of ORS for each vomiting episode 1, 2

Nutritional Management During Illness

Do not withhold food—there is no justification for "bowel rest": 1, 2, 3

• Breastfed infants: Continue nursing on demand without any interruption 4, 1, 2
• Bottle-fed infants: Resume full-strength, lactose-free or lactose-reduced formula immediately upon rehydration 4, 1
• Older children: Resume age-appropriate diet immediately upon rehydration, including starches, cereals, yogurt, fruits, and vegetables 4, 1
• Avoid: Foods high in simple sugars and fats 4

Antiemetic Medication: When and What to Use

Ondansetron is the only antiemetic with sufficient evidence for use in pediatric vomiting: 1, 5, 6, 7

• Dose: 0.15 mg/kg IV/IM or 0.2 mg/kg oral (maximum 4 mg per dose) 1, 5
• Indications: When vomiting prevents adequate oral intake despite small-volume ORS technique, post-operative vomiting, chemotherapy-induced vomiting 5, 6, 7
• Evidence: A single oral dose reduces recurrent vomiting, improves ORS tolerance, and reduces need for IV rehydration and hospitalization 6, 7

Critical contraindications—these antiemetics must be avoided: 1, 3, 8, 9

• Metoclopramide: Contraindicated due to risk of extrapyramidal reactions 1, 8
• Promethazine: Contraindicated in children <2 years; strongly associated with fatal respiratory depression and apnea in all pediatric patients 9
• Antimotility agents (loperamide): Absolutely contraindicated in all children <18 years due to risk of respiratory depression and serious cardiac adverse reactions 3

Antibiotic Considerations

Antibiotics are NOT routinely indicated for vomiting with gastroenteritis. 4 Consider antibiotics only when: 4, 2

• Dysentery (bloody diarrhea) is present
• High fever accompanies diarrhea
• Watery diarrhea persists >5 days
• Stool cultures indicate specific pathogen requiring treatment

Hospitalization Criteria

Admit patients with any of the following: 1, 2

• Severe dehydration (≥10% deficit) or signs of shock
• Intractable vomiting despite ondansetron and small-volume ORS trial
• Altered mental status or lethargy
• High stool output (>10 mL/kg/hour)

Parent Education and Return Precautions

Instruct caregivers to return immediately if: 4, 1, 2

• Decreased urine output develops
• Child becomes lethargic or excessively irritable
• Intractable vomiting continues despite small-volume ORS
• Bloody diarrhea develops

Provide a 24-hour supply of ORS at discharge and emphasize that ORS should be a household staple, like acetaminophen. 1, 2

Key Clinical Pearls

The most common mistake is giving too much fluid too quickly, which perpetuates vomiting. The small-volume technique (5 mL every 1-2 minutes) is the key to success. 4, 1

Do not delay feeding once rehydration is achieved. Early nutritional support combined with oral rehydration guides patients through vomiting episodes safely and effectively. 4

Reassess hydration status after 2-4 hours of rehydration therapy to determine if the patient can transition to maintenance phase with ongoing loss replacement. 3