Flashcards in Chapter 16 Fluid Electrolyte and Acid Base Imbalances Deck (251)
normal sodium ranges
135 to 145 mEq/L
normal BUN ranges
HCT normal levels
35-47% for women and 39-50% for men
Many diseases and their treatments affect fluid and electrolyte balance. For example, a patient with metastatic colon cancer may develop?
hypercalcemia because of bone destruction from tumor invasion.
Chemotherapy used to treat the cancer may result in nausea and vomiting and, subsequently?
dehydration and acid-base imbalances
When correcting dehydration with IV fluids, the patient requires?
close monitoring to prevent fluid overload.
The body is composed primarily of water. It accounts for about _______ of body weight in the adult.
50% to 60%
Water content varies with?
body mass, gender, and age
Lean body mass has a higher percentage of?
water, while adipose tissue has a lesser percentage of water.
water content in women
Women generally have a lower percentage of body water because they tend to have less lean body mass than men
Water content in older adults
Older adults also tend to have less lean body mass, resulting in a lower percentage of body water when compared to younger adults. In older adults, body water content 271averages 45% to 50% of body weight. This places them at a higher risk for fluid-related problems than young adults.
The two fluid compartments in the body are the?
intracellular space (inside the cells) and the extracellular space (outside the cells)
About two thirds of the body water is located?
within cells and is termed intracellular fluid (ICF). ICF makes up about 40% of body weight of an adult.
The two main compartments containing ECF are the?
interstitial fluid, or the fluid in the spaces between cells, and the intravascular fluid or plasma, the liquid part of blood. Other ECF compartments include lymph and transcellular fluids.
Electrolytes are substances whose?
molecules dissociate, or split, into ions when placed in water. Ions are electrically charged particles.
positively charged ions. Examples include sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+) ions
negatively charged ions. Examples include bicarbonate (HCO3−), chloride (Cl−), and phosphate (PO43−) ions. Most proteins bear a negative charge and are thus anions.
Electrolyte composition varies between ECF and ICF. The overall concentration of electrolytes is nearly the same in the two compartments. However, concentrations of specific ions differ greatly.
1) In ECF
2) In ICF
1) ECF the main cation is sodium, with small amounts of potassium, calcium, and magnesium. The primary ECF anion is chloride, with small amounts of bicarbonate, sulfate, and phosphate anions.
2) ICF the most prevalent cation is potassium, with small amounts of magnesium and sodium. The prevalent ICF anion is phosphate, with some protein and a small amount of bicarbonate. See Table 16-1 for normal serum electrolyte values.
Bicarbonate (HCO3−) Levels
22-26 mEq/L (22-26 mmol/L)
Chloride (Cl−) Levels
96-106 mEq/L (96-106 mmol/L)
Phosphate (PO43−) Levels
2.4-4.4 mg/dL (0.78-1.42 mmol/L)
Potassium (K+) Levels
3.5-5.0 mEq/L (3.5-5.0 mmol/L)
Magnesium (Mg2+) Levels
1.5-2.5 mEq/L (0.75-1.25 mmol/L)
Sodium (Na+) Levels
135-145 mEq/L (135-145 mmol/L)
Calcium (Ca2+) (total) Levels
8.6-10.2 mg/dL (2.15-2.55 mmol/L)
Calcium (ionized) Levels
4.6-5.3 mg/dL (1.16-1.32 mmol/L)
The movement of electrolytes and water between ICF and ECF to maintain homeostasis involves many different processes, including simple diffusion, facilitated diffusion, and active transport. Water moves as driven by two forces:
hydrostatic pressure and osmotic pressure.
Diffusion is the movement of molecules from?
an area of high concentration to low concentration. Net movement of molecules stops when the concentrations are equal in both areas. It occurs in liquids, gases, and solids. Simple diffusion requires no external energy.
Facilitated diffusion involves the use of a protein carrier in the cell membrane. The protein carrier combines with a molecule, especially one too large to pass easily through the cell membrane, and assists in moving the molecule across the membrane from?
an area of high to low concentration. Like simple diffusion, facilitated diffusion is passive and requires no energy. An example of facilitated diffusion is glucose transport into the cell. The large glucose molecule must combine with a carrier molecule to be able to cross the cell membrane and enter most cells.