Ringer's lactate solution
Lactated Ringer's solution is a solution that is isotonic with blood and intended for intravenous administration. Veterinary administration may also be subcutaneous.
Lactated Ringer's solution is abbreviated as "LR" or "RL". It is also known as Ringer's lactate solution (although Ringer's solution technically refers only to the saline component, without lactate). It is very similar - though not identical to - Hartmann's Solution, the ionic concentrations of which differ.
Overview
One litre of lactated Ringer's solution contains:
- 130 mEq of sodium ion = 130 mmol/L
- 109 mEq of chloride ion = 109 mmol/L
- 28 mEq of lactate = 28 mmol/L
- 4 mEq of potassium ion = 4 mmol/L
- 3 mEq of calcium ion = 1.5 mmol/L
Generally, the sodium, chloride, potassium and lactate come from NaCl (sodium chloride), NaC3H5O3 (sodium lactate), CaCl2 (calcium chloride), and KCl (potassium chloride).
There are slight variations for the composition for Ringer's as supplied by different manufacturers. As such, the term Ringer's Lactate should not be equated with one precise formulation.[1]
Although its pH is 6.5, it is an alkalinizing solution.
Development of Ringer's solution
Ringer's saline solution was invented by Sydney Ringer,[2] a British physiologist. The solution was further modified by Alexis Hartmann for the purpose of treating acidosis in children. Hartmann modified the solution by adding lactate, which mitigates changes in pH by acting as a buffer for acid. Thus the solution became known as 'Lactated Ringer's Solution' and later, 'Hartmann's solution' [3]
Therapy
Lactated Ringer's solution is often used for fluid resuscitation after a blood loss due to trauma, surgery, or a burn injury. Previously, it was used to induce urine output in patients with renal failure.
Another common use is the treatment of renal failure in small animals, where the solution is administered subcutaneously instead of through an IV. Administering the fluids in this way allows the solution to be given to the animal quickly and does not require a vein to be located. The fluid is then slowly absorbed from under the skin into the bloodstream of the animal.[4]
Lactated Ringer's solution is used because the by-products of lactate metabolism in the liver counteract acidosis, which is a chemical imbalance that occurs with acute fluid loss or renal failure.[5]
The intravenous dose of lactated Ringer's solution is usually calculated by estimated fluid loss and presumed fluid deficit. For fluid resuscitation the usual rate of administration is 20 to 30 ml/kg body weight/hour. Lactated Ringer's solution is not suitable for maintenance therapy because the sodium content (130 mEq/L) is considered too high, particularly for children, whereas the potassium content (4 mEq/L) is too low, in view of electrolyte daily requirement.
Other commonly used intravenous solutions include normal saline and hespan (used in hypovolemic shock). Lactated Ringer's is also used as a conduit for the delivery of drugs. Lactated Ringer's is usually given intravenously, but if a suitable vein is not found, it can be taken orally (although it has an unpleasant taste).
See also
- Intravenous therapy
- Oral rehydration therapy
- Saline (medicine)
- Hartmann's Solution
- Phosphate buffered saline (cell culture)