What is the recommended IV hydration regimen for a patient with moderate signs of dehydration?

IV Hydration for Moderate Dehydration

For moderate dehydration (6-9% fluid deficit), oral rehydration solution (ORS) should be the first-line treatment, not intravenous fluids. 1

Primary Treatment Approach

• Administer reduced osmolarity ORS at 100 mL/kg over 2-4 hours for patients with moderate dehydration 1
• ORS should contain 50-90 mEq/L of sodium 1
• Reassess hydration status after 2-4 hours; if still dehydrated, reestimate deficit and continue ORS 1

When IV Fluids ARE Indicated for Moderate Dehydration

Reserve intravenous fluids for moderate dehydration only when:

• Patient cannot tolerate oral intake 1
• Failure of ORS therapy 1
• Presence of ileus 1
• Ketonemia requiring initial IV hydration to enable oral tolerance 1
• Patient is too weak or refuses to drink adequately (consider nasogastric ORS first) 1

IV Fluid Regimen (When Necessary)

Use isotonic crystalloid solutions:

• Lactated Ringer's solution (preferred) or normal saline 1
• Both are equally effective, though balanced crystalloids like Ringer's lactate likely result in slightly shorter hospital stays and reduced risk of hypokalaemia 2
• Administer at appropriate rates to correct the estimated 6-9% fluid deficit 1

Transition Strategy

Once clinical improvement occurs:

• Switch to ORS as soon as the patient can tolerate oral intake 1
• Continue ORS until clinical dehydration is fully corrected 1
• Replace ongoing stool losses with ORS throughout treatment 1

Critical Monitoring Points

• Reassess pulse, perfusion, and mental status frequently during rehydration 1
• Monitor for signs that patient can transition from IV to oral route 1
• Ensure no risk factors for aspiration before transitioning to oral fluids 1

Common Pitfall to Avoid

Do not automatically use IV fluids for moderate dehydration - this represents overtreatment when ORS is effective in most cases with strong evidence supporting its use 1. The 2017 IDSA guidelines give ORS a "strong, moderate" recommendation for moderate dehydration, while IV fluids are reserved for severe dehydration or specific failure scenarios 1.