Lactated Ringers (LR)

Indications

Intravenous (IV)

Subcutaneous (SQ)

Contraindications

  • Liver Disease (see End-Stage Liver Disease, [[End-Stage Liver Disease]]): impaired hepatic metabolism will impair lactate conversion
  • Metabolic Alkalosis (see Metabolic Alkalosis, [[Metabolic Alkalosis]]): lactated ringers may worsen pre-existing metabolic alkalosis

Pharmacology

Definitions

  • Crystalloids: sodium-based electrolyte solutions

History of Crystalloids

  • 1831 (Europe): first clinical use of crystalloids during the India Blue Cholera pandemic
  • 1896 (Holland): Hartog Hamburger (Dutch physiologist) invented “normal saline”: he intended to use this fluid in the in vitro study of erythrocyte lysis
  • 1880 (England): Sydney Ringer invented “Ringer’s solution”: he used this fluid to sustain contractility in isolated frog hearts
    • The fluid was inadvertently made with tap water (instead of distilled water) and the inadvertent presence of calcium likely led to the experiment being successful
    • Ringer analyzed the fluid and found that it contained calcium, sodium, potassium, chloride, and magnesium
  • 1930’s (USA): pediatrician Alexis Hartmann added lactate to a solution very similar to Ringer’s solution, creating a forerunner of “Lactated Ringer’s” (see Lactated Ringers, [[Lactated Ringers]]): lactate was added by Hartmann to “buffer” the solution (creating a “balanced” solution)

Balanced vs Unbalanced Crystalloids

  • Balanced Crystalloids: mildly hypotonic lactate or acetate buffered solutions (with signficantly lower chloride concentrations than saline)
    • Lactated Ringer’s (LR)
    • Acetate Ringer’s
    • Hartmann Solution
    • Plasma-Lyte (from Baxter Healthcare)
  • Unbalanced Crystalloids : contain no buffer (note: additionally, normal saline has higher chloride concentration than the above)
    • Normal Saline (NS) (see Normal Saline, [[Normal Saline]]): 0.9% NaCl
    • Half Normal Saline (see Half Normal Saline, [[Half Normal Saline]]): 0.45% NaCl
    • Quarter Normal Saline (see Quarter Normal Saline, [[Quarter Normal Saline]]): 0.22% NaCl
    • Dextrose 5% in Water (D5W) (see Dextrose 5% in Water, [[Dextrose 5% in Water]]): Dextrose 5%
    • D5 Normal Saline (D5NS): Dextrose 5% + 0.9% NaCl
    • D5 Half Normal Saline (D5 1/2NS): Dextrose 5% + 0.45% NaCl
    • D5 Quarter Normal Saline (D5 1/4NS): Dextrose 5% + 0.22% NaCl
  • Comparative Data
    • Use of balanced crystalloid is associated with decreased kidney pathology in rat model of hemorrhagic shock, as compared to unbalanced crystalloid [MEDLINE]
    • Chloride-restrictive IV fluid resuscitation strategy is associated with decreased renal injury [MEDLINE]: may be related to hyperchloremia’s induction of renal vasoconstriction

Composition of Lactated Ringers

  • “Balanced” Crystalloid Solution: isotonic with blood
    • Contains 130 mEq of Sodium per liter (130 mmol/L)
    • Contains 109 mEq of Chloride per liter (109 mmol/L)
    • Contains 28 mEq of Lactate per liter (28 mmol/L)
      • Lactate is normally converted to pyruvate by lactate dehydrogenase in the liver (via the Cori cycle) -> pyruvate (the first designated substrate of the gluconeogenesis pathway) is subsequently converted to glucose, a process which generates bicarbonate
    • Contains 4 mEq of Potassium per liter (4 mmol/L)
    • Contains 3 mEq of Calcium per liter (1.5 mmol/L)
  • Similar in composition to Hartmann’s solution (which is more commonly found in British and Irish hospitals)

INTRAVENOUS FLUIDS

Administration

  • IVF Resuscitation: 20 to 30 ml/kg body weight/hr
    • Lactated Ringers is generally considered unsuitable for maintenance fluid therapy, as the sodium content is too low (especially for children)

Adverse Effects

Cardiovascular Adverse Effects

Renal Adverse Effects

  • Hypercalcemia (see Hypercalcemia, [[Hypercalcemia]])
  • Hyperkalemia (see Hyperkalemia, [[Hyperkalemia]]): usually only occurs in the setting of renal failure and high-volume lactated ringers infusion (due to the relatively small amount of potassium per liter)
  • Hyponatremia (see Hyponatremia, [[Hyponatremia]])
  • Metabolic Alkalosis (see Metabolic Alkalosis, [[Metabolic Alkalosis]]): due to hepatic conversion of lactate to bicarbonate

Other Adverse Effects

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References

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