Hypovolemic Hyponatremia (see Hyponatremia, [[Hyponatremia]])
Clinical Efficacy
Single-Center, Multiple-Crossover SALT-ED Trial of Balanced Crystalloids vs Normal Saline in Non-Critically Ill Adults in the Emergency Department (NEJM, 2018) [MEDLINE]: n = 13,347
Among noncritically ill adults treated with intravenous fluids in the emergency department, there was no difference in hospital-free days between treatment with balanced crystalloids and treatment with saline
Hypovolemia/Hypovolemic Shock (see Hypovolemic Shock, [[Hypovolemic Shock]])
Clinical Efficacy
Single-Center, Multiple-Crossover SALT-ED Trial of Balanced Crystalloids vs Normal Saline in Non-Critically Ill Adults in the Emergency Department (NEJM, 2018) [MEDLINE]: n = 13,347
Among noncritically ill adults treated with intravenous fluids in the emergency department, there was no difference in hospital-free days between treatment with balanced crystalloids and treatment with saline
Cluster-Randomized, Multiple-Crossover SMART-MED and SMART-SURG Trial of Balanced Crystalloids vs Normal Saline in Critically Ill Adults (NEJM, 2018) [MEDLINE]: n = 7942 (5 ICU’s)
Balanced Crystalloids (Lactated Ringers or Plasma-Lyte) for Intravenous Fluid Resuscitation Decreased the Composite Outcome of All-Cause Mortality Rate, Need for New Renal Replacement Therapy, and Persistent Renal Dysfunction, as Compared to Normal Saline
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
Isolyte (from Braun)
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%
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)
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)
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)
Hyperlactatemia (see Lactic Acidosis, [[Lactic Acidosis]]): incremental increase in serum lactate is usually small in the absence of an abnormality in lactate clearance (Crit Care Med, 1997) [MEDLINE]
Metabolic Alkalosis (see Metabolic Alkalosis, [[Metabolic Alkalosis]]): due to hepatic conversion of lactate to bicarbonate
Other Adverse Effects
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References
Effect of intravenous lactated Ringer’s solution infusion on the circulating lactate concentration: Part 3. Results of a prospective, randomized, double-blind, placebo-controlled trial. Crit Care Med 1997;25:1851-4 [MEDLINE]
Association between a chloride-liberal vs chloride-restrictive intravenous fluid administration strategy and kidney injury in critically ill adults. JAMA. 2012 Oct 17;308(15):1566-72. doi: 10.1001/jama.2012.13356 [MEDLINE]
Balanced vs unbalanced crystalloid resuscitation in a near-fatal model of hemorrhagic shock and the effects on renal oxygenation, oxidative stress, and inflammation. Resuscitation. 2012 Jun;83(6):767-73. doi: 10.1016/j.resuscitation.2011.11.022. Epub 2011 Dec 4 [MEDLINE]
The ideal crystalloid – what is ‘balanced’? Curr Opin Crit Care. 2013 Aug;19(4):299-307. doi: 10.1097/MCC.0b013e3283632d46 [MEDLINE]
Crystalloids for Fluid Resuscitation in Sepsis: Where Is the Balance? Ann Intern Med. 2014 Jul 22. doi: 10.7326/M14-1565 [MEDLINE]
Balanced Crystalloids versus Saline in Noncritically Ill Adults. N Engl J Med. 2018 Mar 1;378(9):819-828. doi: 10.1056/NEJMoa1711586 [MEDLINE]
Balanced Crystalloids versus Saline in Critically Ill Adults. N Engl J Med. 2018 Mar 1;378(9):829-839. doi: 10.1056/NEJMoa1711584 [MEDLINE]
