LR vs Saline

Q: Lactate Ringer's contain all of the following EXCEPT? (select one)

A) Sodium

B) Chloride

C) Lactate

D) Potassium

E) Magnesium

Answer: E 

Lactated Ringer's Solution was invented about 150 years ago by a British physiologist, Sydney Ringer, though lactate was added afterward. Normal Saline is the solution of 0.9% NaCl. It has a slightly higher degree of osmolality compared to blood. 

One liter of Normal Saline contains

• 154 mEq/L of Na+
• 154 mEq/L of Cl−

One liter of Lactated Ringer's Solution contains:

• 130 mEq/L of Na+ but total cations of 137 mEq/L , so still is isotonic.
• 109 mEq/L of Cl−
• 28 mEq/L of lactate
• 4 mEq/L of potassium
• 3 mEq/L of calcium.

Lactate converts to bicarbonate in liver. Patients with lactic acidosis usually have inadequate liver metabolism of lactate, so conversion to HCO3- from the infused lactate of LR is impaired and may give false readings of serial lactate measurements but may be a better choice in regular situations where hyperchloremia restricts the use of normal saline.

#electrolytes

#hemodynamics

References:

1. Maheshwari K, Turan A, Makarova N, Ma C, Esa WAS, Ruetzler K, Barsoum S, Kuhel AG, Ritchey MR, Higuera-Rueda C, Kopyeva T, Stocchi L, Essber H, Cohen B, Suleiman I, Bajracharya GR, Chelnick D, Mascha EJ, Kurz A, Sessler DI. Saline versus Lactated Ringer's Solution: The Saline or Lactated Ringer's (SOLAR) Trial. Anesthesiology. 2020 Apr;132(4):614-624. doi: 10.1097/ALN.0000000000003130. PMID: 31977517.

2. Friederich A, Martin N, Swanson MB, Faine BA, Mohr NM. Normal Saline Solution and Lactated Ringer's Solution Have a Similar Effect on Quality of Recovery: A Randomized Controlled Trial. Ann Emerg Med. 2019 Feb;73(2):160-169. doi: 10.1016/j.annemergmed.2018.07.007. Epub 2018 Aug 23. PMID: 30146446; PMCID: PMC6340785.