N105: Essentials of Nursing Care - Health Differences

Essentials of Nursing Study Guide

Chapter Four: Fluid and Electrolyte Imbalance

©2017 Achieve Test Prep Page 85 of 160 This is the chemical combining power of the ion or capacity of cations to combine with anions to form molecules. 4.2 Regulation of Body Fluid Compartments Body fluid compartments are separated from each other by cell membranes and capillary membrane, which are selectively permeable because different substances move across themwith varying degrees of ease. The methods by which electrolytes move are as follows: • Osmosis: Fluid moves across a semi-permeable membrane from an area of low solute concentration to an area of high solute. This will continue until the concentrations are equal on both sides of the membrane. Solutes are substances that are dissolved in a liquid 4.1 Principles Related to Normal Fluid and Electrolyte Balance Water accounts for 46-60% of the average adult’s weight. Water is vital to health and normal cellular function. It is a medium for metabolic reactions in cells and it transports nutrients, waste products, and other substances. Water serves as a lubricant, insulator, and shock absorber. Water is one means of regulating body temperature. Essential Terms: • (ECF) Extracellular space: This is fluid outside the cells. ECF composes one third of the body fluid. The transcellular space is the smallest division of ECF containing 1L of fluid. Transcellular fluid includes cerebrospinal, pericardial, synovial, intraocular and pleural fluids, sweat and digestive secretions. • (ICF) Intracellular space: This is fluid in the cells. ICF composes two-thirds of the body fluid and is located primarily in the skeletal muscle mass. ICF is vital to normal cell functioning. ICF contains oxygen, electrolytes, and glucose. • Third Spacing: This is the loss of ECF into a space that does not contribute to equilibrium between the ICF and ECF. In third spacing there is a decrease in urine output even with adequate fluid intake. There is also increased heart rate, decreased blood pressure, edema, and decreased central venous pressure. Third spacing will occur in ascites, burns, peritonitis, bowel obstruction and massive bleeding into a joint or body cavity. • Ions: Ions are excretory products of metabolism contained in ECF and ICF. Ions are charged particles that breakup in water. Positively charged ions are cations (Na+, K+, Ca2+, Mg2+), negatively charges ions are anions (Cl-, HCO3-). • Electrolytes: These are the major cations in body fluid and are sodium, potassium, calcium, magnesium, and hydrogen ions. Major anions are chloride, bicarbonate, phosphate, sulfate, and proteinase ions. Sodium concentration is higher than other ions in ECF. Sodium affects the overall concentration of the fluid and is important in regulating the volume of body fluid. Electrolytes are measured in mEq/L. • Milliequivalent (mEq):