Normal Saline

Normal saline (0.9% NaCl) is isotonic and iso-osmotic but contains more chloride than ECF. When used in large volumes, mild hyperchloremia (i.e., non-anion gap metabolic acidosis) results. Normal saline contains no buffer or other electrolytes. It is preferred to lactated Ringer's solution (which contains a hypotonic concentration of sodium) when brain injury, hypochloremic metabolic alkalosis, or hyponatremia occurs. Many patients with hyperkalemia, including patients with renal failure who are frequently in the operating room for vascular access bypass procedures, routinely receive normal saline because it contains no potassium.