Regarding vomiting seen in the early stages of acute gastroenteritis

It was once common practice to fast (NPO) during vomiting to let the intestines rest, but this approach is no longer recommended.
It has become clear that prolonged fasting and fluid restriction can worsen dehydration and electrolyte abnormalities.

🟡 Medical reasons why oral rehydration is possible even during vomiting
💧 In the intestinal tract, there is a "sodium-glucose cotransport mechanism" that simultaneously absorbs sodium and glucose.
It has been shown that this mechanism is maintained even during vomiting and diarrhea caused by acute gastroenteritis.

As a result,
・Appropriate electrolyte composition
Low osmotic pressure
by administering small amounts of oral rehydration solution (ORS) that meets
Even with vomiting, water and electrolyte absorption is possible.

🟡 Basic Principles of Oral Rehydration Therapy (ORT)

🩺 Domestic and international guidelines for mild to moderate dehydrationOral rehydration therapy (ORT) is the first-line treatmentbefore the onset of the influenza season.

Because giving a large amount at once tends to induce vomiting,
frequent, small-dose administrationis an important point.

🟡 How to give oral rehydration solution by age
Infants and toddlers
Use a spoon or syringe
Dose: approx. 5 mL
Little by little every 2 to 5 minutes

🥤 Elementary school students and older
Dose: Approx. 5–10 mL
Little by little, approximately every 5 minutes
The use of cups and straws is also permitted.

Even if you vomit after drinking water,
After resting for about 10 to 15 minutes, resume in even smaller amounts.
It is not necessary to completely stop oral rehydration therapy due to vomiting.

🟡 Why ORS is considered harder to vomit during the acute phase

🤢 During acute vomiting,Oral rehydration solution (ORS) is less likely to induce vomiting than sports drinks.things,
It has been demonstrated in multiple clinical trials and systematic reviews.

Low-osmolarity ORS (approximately 200–250 mOsm/L) is
Low osmotic load on the gastrointestinal tract
Hardly delays gastric emptying
The ratio of sodium to glucose is optimized for intestinal absorption.

have such characteristics, and
Designed to not worsen vomiting or diarrheaIt is as follows.

BMJ and Cochrane reviews
Compared to conventional ORS and high-sugar drinks, low-osmolarity ORS
- Frequency of vomiting
diarrhea volume
IV insertion rate
has been shown to significantly reduce.

🟡 Why sports drinks are unsuitable for acute gastroenteritis

⚠️ Sports drinks such as Pocari Sweat, Aquarius, and DAKARA,
It is characterized by a high sugar concentration (approximately 6 to 8%) and a low sodium concentration.

Because of this,
- Increased intestinal osmotic pressure
Delayed gastric emptying
Drawing water into the intestinal lumen

are prone to occur,
Potential to promote osmotic diarrhea and vomitingThere is.

These beverages are designed assuming dehydration caused by exercise or sweating,
It is not suitable for rehydration during vomiting and diarrhea caused by infectious gastroenteritis.

🟡 Recommended oral rehydration solution

✅ For rehydration in acute gastroenteritis, use low-osmolarity medical oral rehydration solution.

OS-1
ORS with WHO-recommended composition

These are designed for the prevention and treatment of dehydration during acute gastroenteritis.

🟡 Condition requiring a medical visit
🚑 In the following cases, please consult a medical institution promptly.

・Unable to ingest any fluids, even in small amounts
Frequent vomiting that does not improve
- Urine output is significantly decreased.
- Lips and tongue are dry
Limp and unresponsive

Literature
・Shane AL et al. Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea. Clin Infect Dis. 2017
Flynn TG, Olortegui MP, Kosek MN. Viral Gastroenteritis. Lancet. 2024
・Hahn S, Kim Y, Garner P. Reduced osmolarity oral rehydration solution for treating dehydration due to diarrhoea in children. BMJ. 2001
・Hahn S, Kim S, Garner P. Reduced osmolarity ORS for dehydration caused by acute diarrhoea. Cochrane Database Syst Rev. 2002
· Santosham M et al. A double-blind trial comparing WHO ORS with reduced osmolarity solution. J Pediatr. 1996
Alam NH et al. Symptomatic hyponatremia during treatment with reduced osmolarity ORS. JAMA. 2006
・Colletti JE et al. Management of children with gastroenteritis and dehydration in the emergency department. J Emerg Med. 2010
- CDC. Traveling Safely with Infants & Children. Yellow Book