Why Normal Saline, Not Water, for Wound Irrigation: Hemolysis Risk

Never use sterile water for wound irrigation. It causes hemolysis – osmotic lysis of red blood cells – impairing oxygen delivery and causing complications.

Mechanism of Hemolysis

• Water = hypotonic (0 mOsm/L) vs. plasma (~290 mOsm/L).
• RBCs exposed to water → rapid osmotic influx → swelling → membrane rupture.
• Released hemoglobin: no longer carries O2, scavenges nitric oxide → vasoconstriction, platelet activation, renal tubular toxicity.
• Cell debris → microvascular obstruction.

Normal Saline (0.9% NaCl) Advantage

• Isotonic (~308 mOsm/L) – matches plasma osmolarity.
• Preserves RBC integrity, volume, and oxygen-carrying capacity.
• Compatible with tissue fluids – no osmotic shift.

Clinical Implications

• Surgical fields: Hemolysis obscures visualization, contaminates field.
• Trauma/wound irrigation: Preserves viable tissue, prevents secondary ischemic injury.
• Joint arthroscopy: Water causes hemolysis → compartment syndrome risk.
• Cell salvage: Water-contaminated blood cannot be reinfused.

Alternatives

• Lactated Ringer's: Also isotonic; more physiologic pH/electrolytes.
• Commercial wound cleansers: Surfactant-based, isotonic, preservative-free.

Water is for drinking. Saline is for tissues. This distinction saves limbs and lives.