Concentrations - Saline solution for irrigation - Low, normal, and high concentrations - High concentrations used in molecular biology

Normal Saline - Solution of 0.90% w/v of NaCl - Also referred to as physiological saline or isotonic saline - Used in intravenous drips for dehydration or hypovolemia - Rapid infusion can cause metabolic acidosis - Osmolarity of normal saline is close to that of blood

Usage - Saline used to flush wounds and skin abrasions - No more effective than tap water for wound cleaning - Used in IV therapy for rehydration or maintenance needs - Saline with reduced concentrations used to avoid problems - Saline used for nasal washes to relieve rhinitis and cold symptoms

Hypertonic Saline - Used to hydrate thick secretions and aid expectoration - 3% hypertonic saline used in critical care settings - Inhalation of hypertonic saline helps in respiratory problems - Recommended for cystic fibrosis treatment - Xylitol with saline used in complementary medicine

Other - Half-normal saline (0.45% NaCl) often with D5 - Quarter-normal saline (0.22% NaCl) with 5% dextrose - Hypertonic saline used in perioperative fluid management - Used in treating hyponatremia and cerebral edema - Rapid correction of hyponatremia with saline increases risk of central pontine myelinolysis (CPM)

Solutions with Added Ingredients - Ringers lactate solution - Acetated Ringers solution - Intravenous sugar solutions - 5% dextrose in normal saline (D5NS) - 10% dextrose in normal saline (D10NS)

History - Saline originated during the Indian Blue cholera pandemic in 1831 - William Brooke OShaughnessy proposed injecting cholera patients with highly oxygenated salts - Thomas Latta adopted OShaughnessy's treatment for cholera - Sydney Ringer determined optimal salt concentrations for maintaining heart muscle tissue contractility - Normal saline is considered a descendant of pre-Ringer solutions

Society and Culture - Coconut water has been used as a substitute for normal saline in areas without access - Use of coconut water as a substitute has not been well studied

See also - Intravenous therapy - Saline water - Salinometer

References - Sodium Chloride Injection - FDA prescribing information, side effects and uses - British national formulary: BNF 69 - Critical Care Medicine: The Essentials - Hypertonic Saline - FDA prescribing information, side effects and uses - Fluids and Electrolytes in the Surgical Patient