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.
ReferencesLi 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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