Is it Time to Reconsider the Fluid of Choice in Hypothermia? the Case for Lactated Ringer's Solution.

Current Wilderness Medical Society guidelines for accidental hypothermia recommend 0.9% normal saline (NS) over lactated Ringer's (LR) for fluid resuscitation, citing concerns that a hypothermic liver cannot metabolize lactate. The purpose of this article is to challenge this theoretical premise. We highlight a critical biochemical difference: lactic acid with sodium lactate, the salt found in LR. We propose that the lactate in LR does not contribute to acidosis as it lacks a dissociative proton. In contrast, large-volume NS resuscitation carries the better-documented risk of hyperchloremic non-anion-gap metabolic acidosis. Existing clinical protocols for therapeutic hypothermia and cardiopulmonary bypass already utilize LR safely at severely low core temperatures, demonstrating that a hypothermic body can tolerate balanced solutions without adverse metabolic consequences. Ultimately, the aversion to LR in accidental hypothermia warrants pause and further investigation. We recommend that clinical guidelines be updated to reflect physiological realities and allow for future studies comparing crystalloid fluids.