Hydration Therapy Dose in Severe Dehydration
Immediate Management
For severe dehydration (≥10% fluid deficit, shock, or near shock) due to diarrhea, initiate immediate intravenous rehydration with boluses of 20 mL/kg of Ringer's lactate or normal saline, repeated until pulse, perfusion, and mental status normalize, then transition to oral rehydration solution for the remaining deficit. 1
Initial Resuscitation Phase
- Administer 20 mL/kg IV boluses of isotonic crystalloid solution (Ringer's lactate or normal saline) rapidly 1
- Repeat boluses until hemodynamic stability is achieved: normal pulse, adequate perfusion, normal mental status 1
- This may require two IV lines or alternate access sites (venous cutdown, femoral vein, intraosseous infusion) in critically ill patients 1
- Ringer's lactate is preferred over normal saline as it is associated with reduced mortality and less acute kidney injury in critically ill patients, though both are acceptable 1, 2
Transition to Oral Rehydration
- Once consciousness returns to normal, the patient can take the remaining estimated fluid deficit by mouth using oral rehydration solution (ORS) 1
- The transition should occur when the patient awakens, has no risk factors for aspiration, and has no evidence of ileus 1
- Do not continue aggressive IV boluses once hemodynamic stability is achieved 1
Ongoing Fluid Replacement
Replacement of Continuing Losses
- Administer 10 mL/kg of ORS for each watery or loose stool passed 1
- Administer 2 mL/kg of ORS for each episode of vomiting 1
- If stool losses can be measured accurately, give 1 mL of ORS for each gram of diarrheal stool 1
- Use ORS containing 50-90 mEq/L of sodium for replacement of ongoing losses 1
Monitoring and Reassessment
- Reassess hydration status frequently during treatment to monitor adequacy of replacement therapy 1
- Check vital signs, perfusion, mental status, and signs of dehydration after 2-4 hours 1
- Monitor for complications including electrolyte abnormalities, particularly hypokalemia 1, 2
Key Clinical Pitfalls
Severe dehydration constitutes a medical emergency requiring immediate IV access and aggressive fluid resuscitation 1. The most common error is delaying IV therapy or attempting oral rehydration in a patient with shock or altered mental status. However, once the patient is stabilized hemodynamically, premature continuation of IV fluids when oral rehydration is feasible represents overtreatment 1. The evidence shows that approximately 4% of children treated with ORS will fail and require IV therapy, but the vast majority can successfully transition to oral rehydration once consciousness normalizes 1.
Do not use popular beverages such as apple juice, Gatorade, or commercial soft drinks for rehydration, as these lack appropriate electrolyte composition 1. Only use properly formulated ORS solutions containing 50-90 mEq/L of sodium 1.