Contributor: Travis Barlock, MD

Educational Pearls:

Normal Saline (NS) contains 154 mEq of both Sodium (Na) and Chloride (Cl), and has a pH of 5.5

Normal Na and Cl in adult humans are about 140 mEq/L and 103 mEq/L. respectively

Excess negative charge resulting from hyperchloremia is managed via bicarbonate excretion leading to loss of base

Overall, administration of NS drives metabolic acidosis

Lactated Ringers (LR) contains 130 mEq of Na and 109 mEq Cl, and has a pH of 6.5
LR components are closer to physiologic levels thus may generally be a more efficacious fluid choice
NS is still frequently given in scenarios where there is concern for increased intracranial pressure or existing hypochloremic alkalosis from emesis.

References
Li H, Sun SR, Yap JQ, Chen JH, Qian Q. 0.9% saline is neither normal nor physiological. J Zhejiang Univ Sci B. 2016;17(3):181-187. doi:10.1631/jzus.B1500201

Lehr AR, Rached-d'Astous S, Barrowman N, et al. Balanced Versus Unbalanced Fluid in Critically Ill Children: Systematic Review and Meta-Analysis. Pediatr Crit Care Med. 2022;23(3):181-191. doi:10.1097/PCC.0000000000002890

Self WH, Semler MW, Wanderer JP, et al. Saline versus balanced crystalloids for intravenous fluid therapy in the emergency department: study protocol for a cluster-randomized, multiple-crossover trial. Trials. 2017;18(1):178. Published 2017 Apr 13. doi:10.1186/s13063-017-1923-6

Semler MW, Self WH, Wanderer JP, et al. Balanced Crystalloids versus Saline in Critically Ill Adults. N Engl J Med. 2018;378(9):829-839. doi:10.1056/NEJMoa1711584

Summarized by Kirsten Hughes, MS4 | Edited by John Spartz, MD, & Erik Verzemnieks, MD

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Podcast 833: NS vs LR