than 3% NaCl should normally be administered via a central venous catheter, also known as a 'central line'. Such hypertonic saline is normally available in two strengths, the former of which is more commonly administered: 3% NaCl has 513 mEq/L of Na and Cl. 5% NaCl has 856 mEq/L of Na and Cl. NaCl solutions that are less commonly used are 7% (1200 mEq/L) and 23.4% (approx 4000 mEq/L), both of which are used (also via central line), often in conjunction with supplementary diuretics, in the treatment of traumatic brain injury. Dextrose (glucose) 4% in 0.18% saline is used sometimes for maintenance replacement. Solutions with added ingredients In medicine, common types of salines include: Ringer's lactate solution Acetated Ringer's solution Intravenous sugar solutions 5% dextrose in normal saline (D5NS) 10% dextrose in normal saline (D10NS) 5% dextrose in half-normal saline (D5HNS) 10% dextrose in half-normal saline (D10HNS) And in cell biology, in addition to the above the following are used: Phosphate buffered saline (PBS) (recipes from Dulbecco = D-PBS, Galfre, Kuchler, Ausubel etc.) TRIS-buffered saline (TBS) (recipes from Goldsmith, Ausubel etc.) Hank's balanced salt solution (HBSS) Earle's balanced salt solution (EBSS) Standard saline citrate (SSC) HEPES-buffered saline (HBS) (recipes from Dittmar, Liu, Ausubel etc.) Gey's balanced salt solution (GBSS) History Saline was believed to have originated during the Indian Blue cholera pandemic that swept across Europe in 1831. William Brooke O'Shaughnessy, a recent graduate of Edinburgh Medical School, proposed in an article to medical journal The Lancet to inject people infected with cholera with highly oxygenated salts to treat the "universal stagnation of the venous system and rapid cessation of arterialisation of the blood" seen in people with severely dehydrated cholera. He found his treatment harmless in dogs, and his proposal was soon adopted by the physician Thomas Latta in treating people with cholera to beneficial effect. In the following decades, variations and alternatives to Latta's solution were tested and used in treating people with cholera. These solutions contained a range of concentrations of sodium, chloride, potassium, carbonate, phosphate, and hydroxide. The breakthrough in achieving physiological concentrations was accomplished by Sydney Ringer in the early 1880s, when he determined the optimal salt concentrations to maintain the contractility of frog heart muscle tissue. Normal saline is considered a descendant of the pre-Ringer solutions, as Ringer's findings were not adopted and widely used until decades later. The term "normal saline" itself appears