IVF

I. CRYSTALLOID FLUIDS

1. Normal Saline (0.9% NaCl)

MOA

• Isotonic fluid

• Expands extracellular fluid (ECF) → stays in intravascular & interstitial spaces

• No shift into cells (no osmotic pull)

Indications

• Hypovolemia / dehydration

• Shock

• Hyponatremia

• DKA (initial fluid)

• Blood transfusions (only fluid compatible)

• Sepsis fluid resuscitation

Contraindications / Cautions

• Hyperchloremic metabolic acidosis

• Heart failure

• Renal failure → risk of fluid overload

• Avoid large volumes in traumatic brain injury (increases chloride → worsens acidosis)

2. Lactated Ringers (LR)

MOA

• Isotonic balanced crystalloid

• Contains Na, K, Ca, Cl + lactate (converted to bicarbonate by liver)
  → Buffers acidosis, expands ECF.

Indications

• Surgery

• Burns

• Trauma

• GI fluid loss

• Metabolic acidosis

Contraindications / Cautions

• Liver failure (cannot metabolize lactate → lactic acidosis)

• Hyperkalemia (contains K⁺)

• Blood transfusion compatibility issues (Ca²⁺ may bind citrate)

3. D5W (5% Dextrose in Water)

MOA

• Starts isotonic → becomes free water after dextrose is metabolized

• Expands intracellular fluid (ICF)

• Hydrates cells

Indications

• Hypernatremia

• Dehydration with high sodium

• Free water replacement

• Hypoglycemia (mild)

Contraindications / Cautions

• Do NOT use for resuscitation

• Increased ICP (goes into brain cells → swelling)

• SIADH

• Hyperglycemia

• Fluid overload

4. Half Normal Saline (0.45% NaCl)

MOA

• Hypotonic

• Hydrates cells (ICF)

• Some ECF expansion

Indications

• Hypernatremia

• Severe dehydration when cells are dehydrated

• Maintenance fluid for mild GI losses

Contraindications / Cautions

• Increased ICP

• Burns

• Trauma

• Liver disease

• Risk of worsening hyponatremia

5. Hypertonic Saline (3%, 5%, 7% NaCl)

MOA

• Draws water out of cells → into bloodstream

• Expands intravascular volume, reduces cerebral edema

Indications

• Severe hyponatremia

• Increased ICP / cerebral edema

• SIADH

Contraindications / Cautions

• Must be given through central line (except 3%)

• Risk of central pontine myelinolysis if sodium rises too fast

• Pulmonary edema

• Heart failure

• Renal failure

II. DEXTROSE COMBINED FLUIDS

6. D5NS (5% Dextrose in Normal Saline)

MOA

• Hypertonic

• Expands ECF and provides calories

Indications

• Hypovolemia + hypoglycemia

• Temporary TPN substitute

• Dehydration requiring glucose + sodium

Contraindications

• Renal or heart failure

• Hypernatremia

• Hyperglycemia

• Increased ICP

7. D51/2NS (5% Dextrose + 0.45% Saline)

MOA

• Slightly hypertonic

• Provides free water + sodium + glucose

• Maintenance fluid

Indications

• Most common maintenance IV fluid

• Post-op hydration

• Mild sodium-loss dehydration

Contraindications

• Hypernatremia

• Increased ICP

• DKA (not initial)

• SIADH

• Heart/kidney failure

8. D5LR

MOA

• Hypertonic version of LR

• Provides electrolytes + glucose

• Expands intravascular volume

Indications

• Burns

• GI fluid loss when glucose is needed

• Pre-surgery in certain patients

Contraindications

• Liver failure

• Hyperglycemia

• Hyperkalemia

• Increased ICP

III. COLLOIDS

(rarely used but important for exams)

9. Albumin (5%, 25%)

MOA

• Large protein solution → stays in intravascular space

• Pulls water from tissues → plasma

• Increases oncotic pressure

Indications

• Burns

• Hepatorenal syndrome

• Severe hypoalbuminemia

• Volume expansion in cirrhosis

• Third-spacing

Contraindications

• Heart failure

• Renal failure

• Active bleeding

• Costly and can cause anaphylaxis

10. Dextran / Gelatin Solutions

MOA

• Synthetic volume expanders

• Increase intravascular volume

Indications

• Rarely used except in trauma (not common in US)

Contraindications

• Coagulopathy

• Renal failure

• Anaphylaxis risk

IV. Balanced Solutions (Newer / ICU-focused)

11. Plasma-Lyte / Normosol

MOA

• Balanced crystalloid similar to plasma

• Contains acetate + gluconate (metabolized to bicarbonate)

Indications

• Sepsis

• ICU fluid resuscitation

• Metabolic acidosis

• Trauma

• Better than NS for kidney perfusion

Contraindications

• Hyperkalemia

• Severe alkalosis

Master Summary Table

Fluid	Type	Indications	Contraindications	MOA
NS	Isotonic	Shock, dehydration, hyponatremia	HF, metabolic acidosis	Expands ECF
LR	Isotonic	Burns, trauma, surgery	HyperK, liver failure	ECF expansion + buffer
D5W	Hypotonic (after metabolism)	Hypernatremia, dehydration	ICP ↑, seizures	Free water → ICF
1/2NS	Hypotonic	Hypernatremia, dehydration	Burns, trauma, ↑ICP	Hydrates cells
3% Saline	Hypertonic	Severe hyponatremia, cerebral edema	HF, renal fail	Pulls fluid out of cells
D5NS	Hypertonic	Hypovolemia + low sugar	HTN, HF	ECF expansion + calories
D51/2NS	Hypertonic	Maintenance fluid	SIADH, ↑ICP	ECF + free water
D5LR	Hypertonic	Burns, GI loss	Liver failure	ECF + electrolytes + glucose
Albumin	Colloid	Burns, cirrhosis, shock	HF, renal fail	Oncotic pull
Plasma-Lyte	Balanced	ICU, sepsis	HyperK	Balanced ECF expansion