Sodium and Potassium Abnormalities
Managing electrolyte abnormalities effectively requires that the critical care surgeon understands the organization and equilibrium of intracellular and extracellular (including the interstitial and intravascular) fluid compartments. Fluid shifts and subsequent electrolyte derangements are common in the surgical patient in the postoperative period as well as in the trauma patient. Sodium is the predominant cation in the extracellular compartment, while potassium dominates the intracellular space. Derangements in sodium homeostasis (hypo- or hypernatremia) are largely related to volume status (hypo-, eu-, or hypervolemia) and as such can be treated with some measure of fluid restriction and diuretics or volume administration. As the major intracellular cation, potassium plays integral roles in nerve conduction, ATPase transmembrane pumps, and cardiac myocyte excitability. Seemingly minor changes in potassium levels (hyper- or hypokalemia) can have significant physiologic consequences. Accordingly, there are a multitude of options with which to replete potassium or shift its location either intracellular (insulin or albuterol) or out of the body (diuretics or dialysis).
KeywordsHyponatremia Hypernatremia Hypokalemia Hyperkalemia Fluid compartments
- 7.Kamel KS, Halperin ML. Fluid, electrolyte and acid-base physiology. 5th ed. Philadelphia: Elsevier; 2017.Google Scholar
- 9.Rhoades R, Bell DR. Regulation of fluid and electrolyte balance. In: Rhoades R, Bell DR, editors. Medical physiology: principles for clinical medicine. Baltimore: Lippincott Williams and Wilkins; 2013.Google Scholar
- 10.Rose BD, Post TW. Regulation of the effective circulating volume. In: Rose Burton D, Post TW, editors. Clinical physiology of acid-base and electrolyte disorders. New York: McGraw-Hill; 2001.Google Scholar
- 11.Rose BD, Post TW. Regulation of plasma osmolality. In: Rose BD, Post TW, editors. Clinical physiology of acid-base and electrolyte disorders. New York: McGraw-Hill; 2001.Google Scholar
- 12.Rose BD, Post TW (2001). Hypoosmolal states: hyponatremia. In Rose BD & Post TW (Eds.), Clinical physiology of acid-base and electrolyte disorders. New York: McGraw-Hill.Google Scholar