From the Research
For maintenance fluid therapy after vomiting-induced dehydration, Lactated Ringer's (LR) solution should be administered at a rate of 2-4 mL/kg/hour for adults, adjusted based on the patient's clinical status, as supported by the most recent study 1.
Key Considerations
- For children, use the 4-2-1 rule: 4 mL/kg/hour for the first 10 kg of body weight, plus 2 mL/kg/hour for the next 10 kg, plus 1 mL/kg/hour for each additional kg.
- Before maintenance therapy, assess if the patient needs initial rehydration with a bolus of 20 mL/kg LR over 1 hour for moderate dehydration.
- Monitor the patient's vital signs, urine output, and electrolyte levels during therapy, adjusting the rate as needed.
- LR is preferred over normal saline for most patients because its electrolyte composition more closely resembles plasma, reducing the risk of hyperchloremic metabolic acidosis with prolonged use, as noted in 2 and 1.
Additional Therapy
- Continue maintenance fluids until the patient can tolerate adequate oral intake, typically reassessing every 4-6 hours.
- If vomiting persists, consider adding an antiemetic such as ondansetron 4-8 mg IV for adults or 0.15 mg/kg for children to help transition to oral rehydration.
Evidence Support
- The study 3 comparing oral, intravenous, and subcutaneous fluid therapy for resuscitation of calves with diarrhea, although not directly applicable to humans, suggests that oral electrolytes can be as effective as intravenous fluids in treating dehydration, supporting the idea of transitioning to oral rehydration when possible.
- The comparison of hypertonic saline-dextran solution and lactated Ringer's solution for resuscitating severely dehydrated calves 4 indicates that lactated Ringer's can be effective in resuscitation, further supporting its use in humans.
- The maintenance fluid therapy study 1 provides the most recent and direct evidence for the use of lactated Ringer's solution in children, highlighting its benefits in maintaining metabolic balance.