The Art and Science of Infusion Nursing Ann H. Crawford , PhD, RN, CNS, CEN Hyperkalemia: Recognition and Management of a Critical Electrolyte Disturbance luids and electrolytes are vital for regulating ABSTRACT and maintaining virtually every aspect of Electrolytes, in the right balance, are essential for body function. This article will focus on the regulating body functions and maintaining health. specific abnormality of hyperkalemia; how- Even small deviations from normal electrolyte ever, a brief overview of fluid and electro- concentrations may cause significant problems. lytes may be beneficial for understanding normal F Hyperkalemia is acknowledged as one of the function. most dangerous electrolyte abnormalities. Body fluid—mainly water—makes up about two- Symptoms are nonspecific and predominately thirds of an adult’s total body weight. The amount of related to cardiac or neuromuscular dysfunction, fluid and how it is distributed in the body varies in rela- with potentially life-threatening consequences. tion to an individual’s age, gender, and body build. Lean body muscle mass is rich in water, while adi- Immediate and decisive treatment is necessary to pose, or fat, tissue is nearly water-free. The leaner the lower the serum potassium level and to prevent person, the greater the proportion of water in relation a recurrence. This article reviews the to total body weight. This concept aligns with gender pathophysiologic causes of hyperkalemia and and age as well. Women tend to have a lower water- discusses the manifestations, diagnostic tests, percentage weight than men because of the higher con- and various treatment options available to centration of fat content in their bodies. Similarly, as manage this electrolyte abnormality. individuals age, they are predisposed to have a lower Key words: aldosterone , calcium gluconate , water-weight percentage overall as a result of a decrease cardiac dysrhythmias , dialysis , diuretics , in their muscle mass content. 1-3 electrolytes , extracellular , hyperkalemia , insulin , Fluid in the body is located in 2 major compart- intracellular , renal failure ments: the intracellular space and the extracellular space. Extracellular fluids (ECFs) are further divided into intravascular fluid (blood plasma), transcellular fluids (water within epithelial-lined spaces), and inter- stitial fluid (tissue spaces surrounding the cells). Infants Author Affiliation: Professor, College of Nursing, University of and children have a greater percentage of fluid in the Mary Hardin-Baylor, Belton, Texas. interstitial spaces, which makes them more susceptible Ann H. Crawford, PhD, RN, CNS, CEN, is a professor of nursing to fluid volume deficit problems. 2 , 3 at the University of Mary Hardin-Baylor. She serves on the under- graduate and graduate faculties. Dr. Crawford earned her bachelor’s and master’s degrees at the University of North Dakota. She obtained her doctorate in education at Texas A&M University. In addition to ELECTROLYTES teaching, Dr. Crawford works in the emergency department of a local hospital, McLane Children’s Baylor Scott & White, in Temple, Texas. Electrolytes, or ions, are small, electrically charged The author of this article has no conflicts of interest to disclose. elements located in body fluid, tissue, and blood. They Corresponding Author: Ann H. Crawford, PhD, RN, CNS, CEN, University of Mary Hardin-Baylor, 900 College Street, PO Box 8015, are critical in maintaining proper cellular activity, Belton, TX 76513 ( [email protected] ). facilitating oxygenation, controlling fluid and acid-base DOI: 10.1097/NAN.0000000000000036 balance, and regulating many body functions. Common VOLUME 37 | NUMBER 3 | MAY/JUNE 2014 Copyright © 2014 Infusion Nurses Society 167 Copyright © 2014 Infusion Nurses Society. Unauthorized reproduction of this article is prohibited. JJIN-D-13-00027R1.inddIN-D-13-00027R1.indd 116767 33/24/14/24/14 88:11:11 AAMM electrolytes include sodium, potassium, calcium, phos- (high solute concentration). Fluid is moving from an phorus, magnesium, chloride, and sodium bicarbonate. area with little solute to an area of more dense solute in Body fluids are electronically neutral; however, the an effort to “dilute” the latter. The movement occurs distribution of electrolytes varies within the ECF and until the fluids on both sides of the permeable mem- intracellular fluid (ICF). Like fluid, their levels are con- brane contain equal concentrations of solute. No energy trolled by a variety of hormones, such as renin, aldos- is required because the movement follows an ordinary terone, and antidiuretic hormone (ADH). Electrolytes flow on the gradient concentration and does not require function optimally within a narrow range, and small assistance to occur. 3 , 4 shifts of any select electrolyte can have a significant Filtration is the movement of fluid from 1 side of a effect on body function. membrane to another because of a difference in pressure Sodium (Na + ) is concentrated in the ECF, whereas exerted on the 2 sides of the membrane wall. The fluid potassium (K + ) is concentrated in the ICF. Sodium and compartment with the higher pressure forces the fluid potassium share a unique reciprocal relationship with across the membrane toward the fluid compartment their ICF/ECF levels and movement. For example, fol- exerting a lower pressure until equilibrium occurs. lowing depolarization of cardiac cells, use of the Although pressure is used, no energy is expended, so it sodium-potassium pump facilitates the return of these is a form of passive transport. 3 , 4 electrolytes to their respective fluid compartments dur- Active transport involves moving solutes from an ing repolarization. In the repolarization process, sodium area of low solute concentration to an area of high sol- does not move back to the extracellular area passively, ute concentration, moving against a concentration gra- so energy use is required to facilitate this movement. As dient. Energy is required to help carry the molecules the sodium is transported into the ECF, potassium shifts because it is forcing fluids and/or electrolytes to move back into the intracellular space to maintain overall against the natural concentration gradient flow electrolyte charge neutrality. Proper balance is essential (“uphill”). Energy is provided by adenosine triphos- for muscle coordination, cardiac function, fluid absorp- phate (ATP), a nucleoside triphosphate used in cells as tion and excretion, neuromuscular function, and appro- a coenzyme. When generated by the metabolism of priate mentation. 3-5 glucose or fat within a cell, chemical energy is released for physiologic function and needs of the body. Active transport requires the use of the energy produced by the FLUID AND ELECTROLYTE hydrolysis of ATP to force the solute back across the MOVEMENT membrane to where it needs to be. 3 , 4 An example of an active transport mechanism in the body is the sodium- Fluids and electrolytes are constantly moving between potassium pump. To maintain the normal resting poten- the compartments to maintain a homeostatic state. tial, sodium has a high concentration extracellularly, When the fluid spaces on either side of a membrane and potassium has a high concentration intracellularly. contain differing amounts of particles (solutes), a con- The natural inclination is to move to equalize these centration gradient occurs. The body uses several means electrolyte levels. For example, with cardiac depolariza- of moving fluid and/or particles to alter these concen- tion, sodium shifts into the cell, causing potassium to trations and attain equilibrium. The 2 major types of shift out of the cell to facilitate contraction of the heart movement for fluids and electrolytes include passive muscle. During repolarization, the electrolytes must be transport and active transport. moved back to their original positions to be ready for In passive transport, several mechanisms facilitate the next needed shift. Because this movement requires fluid and electrolyte shifts, including diffusion, osmosis, the electrolytes to move against the concentration gradi- and filtration. 3 , 4 Passive transport does not require ent, ATP energy is needed to force them back. Through energy to cause a fluid/electrolyte compartmental shift. active transport, the sodium-potassium pump transfers No work is required because the movement is going 3 sodium ions out of the cell in exchange for moving 2 down the concentration gradient in the natural flow. potassium ions back into the cell. This is responsible for The first type of passive transport, diffusion, is the preserving the large concentration of sodium ions out- movement of solute, including electrolytes, across a side the cell and the large concentration of potassium permeable membrane from a high concentration to a ions inside. 3 , 4 low concentration of that solute. The particles flow In addition to passive and active transport, hydro- across the permeable membrane as they shift from a static pressure works reciprocally with osmotic pressure more crowded state to a lower-density area. This high- in the vascular space to preserve vascular fluid levels. to-low, or “downhill,” movement of the particles con- Hydrostatic pressure is the pressure that fluid exerts on tinues until a balance is achieved. 3 , 4 the walls of its container to leave the container. Osmotic Osmosis is the movement of fluid (solvent) from an pressure is the pressure required to prevent the flow of area of higher fluid concentration (low