Maintenance Fluid Dosing for Moderate Dehydration

Route Selection: Oral vs Intravenous

The Infectious Diseases Society of America recommends oral rehydration solution as the first-line treatment for moderate dehydration in adults who can tolerate oral intake, with strong evidence (strong, low quality) that adults with mild to moderate dehydration should receive ORS until clinical dehydration is corrected 1, 2
Oral rehydration solution is recommended for adults with moderate dehydration, with a dosage of 120-240 mL after each diarrheal stool or vomiting episode, up to approximately 1 liter per day, until clinical dehydration is corrected 1

The American College of Physicians and the Infectious Diseases Society of America suggest administering 120-240 mL of ORS after each diarrheal stool or vomiting episode, with a maximum daily intake of approximately 1 liter (up to 2 liters if tolerated) 1
Continue ORS until clinical signs of dehydration resolve (normal pulse, perfusion, mental status) 1, 2

The Society of Critical Care Medicine recommends administering 20 mL/kg isotonic crystalloid bolus (approximately 844 mL for a 42.2kg patient) over the first hour, followed by 1.5 mL/kg/hour (approximately 63 mL/hour for a 42.2kg patient) once hemodynamically stable 6
Use lactated Ringer's or normal saline, and add 20 mEq/L potassium chloride after urine output is established 1, 3

The European Society for Clinical Nutrition and Metabolism recommends resuming a normal age-appropriate diet every 3-4 hours, and continuing to replace ongoing losses with ORS until diarrhea/vomiting resolves 1, 2
Target daily fluid intake is 1.6 liters for women 5

The World Health Organization and the Infectious Diseases Society of America state that a patient is adequately rehydrated when pulse normalizes, perfusion improves, mental status returns to baseline, and urine output is adequate (>0.5 mL/kg/hour) 1, 6