How do you choose between Normal Saline (NS), Ringer's Lactate (RL), 5% Dextrose in Normal Saline (DNS), and 25% Dextrose (25D) for fluid resuscitation?

Fluid Selection for Resuscitation

For most patients requiring fluid resuscitation, use balanced crystalloids (Lactated Ringer's or similar) as first-line therapy rather than Normal Saline, with the critical exception of traumatic brain injury where Normal Saline is mandatory. 1, 2, 3

Primary Recommendation: Balanced Crystalloids First

Balanced crystalloids like Lactated Ringer's should be your default choice because they reduce major adverse kidney events, lower mortality, and avoid hyperchloremic metabolic acidosis compared to Normal Saline. 1, 3

Evidence Supporting Balanced Crystalloids:

• The SMART trial (n=15,802 critically ill patients) demonstrated lower rates of major adverse kidney events with balanced crystalloids versus saline 1
• The SALT trial showed lower 30-day in-hospital mortality and reduced need for renal replacement therapy with balanced crystalloids 4, 1
• KDIGO guidelines recommend isotonic crystalloids for AKI prevention, with emerging evidence favoring balanced solutions 4, 1
• The 2023 ERAS guidelines for emergency laparotomy state balanced crystalloids may result in improved patient outcomes and reduced morbidity/mortality 4

Why Balanced Crystalloids Are Superior:

• Avoid hyperchloremic acidosis: Normal Saline contains 154 mmol/L chloride (supraphysiologic), causing metabolic acidosis with large volumes 1, 3
• Reduce kidney injury: NS causes renal afferent arteriolar vasoconstriction, reducing GFR, while balanced solutions avoid this 1
• Better outcomes in sepsis: Surviving Sepsis Campaign 2025 guidelines recommend balanced crystalloids for septic shock 3
• Faster DKA resolution: Balanced fluids associated with shorter time to DKA resolution versus NS 5
• Lower mortality in acute pancreatitis: LR associated with reduced 1-year mortality (adjusted OR 0.61) 6

When to Use Normal Saline Instead

Mandatory Indications:

• Traumatic brain injury: NS is strongly recommended as first-line fluid 1, 2, 3
• Severe hyponatremia: NS helps correct sodium deficits without further dilution 2
• Metabolic alkalosis: The relative acidifying effect of NS can help correct alkalosis 2

Volume Limitation:

• If using Normal Saline, limit to maximum 1-1.5 liters to minimize hyperchloremic acidosis risk 1, 2

When to Avoid Lactated Ringer's

Contraindications:

• Traumatic brain injury (use NS instead) 1, 2
• Severe liver dysfunction (impaired lactate metabolism) 2
• Severe hyperkalemia (LR contains potassium) 2

Common Misconception:

• LR does not worsen lactic acidosis despite containing lactate—the lactate is metabolized to bicarbonate 2

Specific Clinical Scenarios

Septic Shock:

• Use balanced crystalloids for the initial 30 mL/kg bolus within 3 hours 3
• Continue balanced crystalloids for ongoing resuscitation 3
• Monitor for volume overload in heart failure or CKD patients 3

Hemorrhagic Shock:

• Without TBI: Use Lactated Ringer's—requires significantly less volume than NS and avoids dilutional coagulopathy 7
• With TBI: Use Normal Saline despite hemorrhage 2
• Target systolic BP 80-90 mmHg until bleeding controlled (permissive hypotension) 2

Acute Kidney Injury:

• Use balanced crystalloids to reduce major adverse kidney events 1
• Avoid excessive fluid administration regardless of type—both can cause volume overload 1
• Guide administration by hemodynamic reassessment (lactate clearance, urine output, MAP) 1

Trauma (Non-TBI):

• European guidelines recommend either 0.9% saline or balanced crystalloids for hypotensive bleeding trauma 1
• Recent evidence favors balanced crystalloids for better outcomes 4, 1

Pediatric/Neonatal Hypovolemia:

• First-choice fluid is isotonic saline at 10-20 mL/kg initial bolus 4
• Repeated doses based on clinical response 4
• When large volumes required (e.g., sepsis), synthetic colloid may be considered for longer intravascular duration 4

Dextrose Solutions (DNS, 25D)

5% Dextrose in Normal Saline (DNS):

• Not for resuscitation—dextrose-containing fluids are maintenance fluids, not resuscitation fluids
• Used for maintenance when patient needs both volume and glucose (e.g., NPO status, hypoglycemia risk)
• Provides free water and calories

25% Dextrose (25D):

• Not for resuscitation—this is a concentrated glucose solution
• Used specifically for hypoglycemia treatment
• Requires central line or careful peripheral administration due to high osmolarity
• Typical dose: 0.5-1 g/kg for severe hypoglycemia

Colloids vs Crystalloids

Use crystalloids over colloids for initial resuscitation. 4

Why Crystalloids Are Preferred:

• No mortality benefit with colloids versus crystalloids 4
• Colloids have potential infection hazard and anaphylactic reaction risk 4
• Colloids are significantly more expensive (albumin ~140 Euro/L, HES ~25 Euro/L vs isotonic saline ~1.5 Euro/L) 4
• Hydroxyethyl starch (HES) increases risk of kidney failure, mortality, and bleeding—avoid in severe sepsis 4

Practical Algorithm

1. Identify if TBI present: If yes → Normal Saline (maximum consideration for other indications)
2. If no TBI: Use Lactated Ringer's or balanced crystalloid as default
3. Check for LR contraindications: Severe liver dysfunction or severe hyperkalemia → use NS (limit 1-1.5L)
4. For ongoing resuscitation: Continue balanced crystalloids unless specific indication for NS
5. Monitor: Electrolytes, acid-base status, renal function, and volume status
6. Never use dextrose solutions for resuscitation—reserve for maintenance or hypoglycemia treatment