NURS 112 - Fluid & Electrolytes
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83 terms
Terms | Definitions |
|---|---|
 How much does weight vary in 24 hours for a healthy person? | >0.2 kg (0.5 lb) regardless of the amount of fluid ingested. |
| Vital functions of water to health and normal cellular function. | Medium for metabolic reactions within cells. Transport nutrients, waste, and other substances. Function as a lubricant, insulator, and shock absorber. Regulate and maintain body temperature. |
| Factors affecting total body water. (3) | Age, Sex, & Body fat |
| The proportion of body water decreases with age. True or False | True. In people older than 60 years of age, it represents only about 50% of the total body weight. |
| Intracellular Fluid (ICF) | Found within the cells of the body and is vital to normal functioning of the cell. Two-thirds of total body fluid in adults. |
| Solutes of intracellular fluids | Oxygen, electrolytes, and glucose, and provides a medium in which metabolic processes of the cell take place. |
| Extracellular Fluid (ECF) | Found outside the cells and accounts for the remaining one-third of total body fluid. Carries nutrients to and waste products from the cells. |
| Two main compartments of ECF. | Intravascular and Interstitial The others are the lymph and transcellular fluid. |
| Intravasuclar Fluid | Plasma; ~ 20% of the ECF and is found within the vascular system. |
| Interstitial Fluid | ~ 75% of the ECF and surrounds the cells. Transports wastes from the cells by way of the lymph system. |
| Ions | An ion is charged particle - atom or molecule - in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. |
| Electrolytes | Any substance containing free ions that make the substance electrically conductive(capable of conducting electricity). |
| Cations | Ions that carry a positive charge. |
| Anions | Ions that carry a negative charge. |
| mEq/L | milliequivalents per liter; milliequivalents refers to the chemical combining power of the ion, or the capacity of cations to combine with anions to form molecules. |
| The principal electrolytes of extracellular fluid. | Sodium (Na+), Chloride (Cl-), and Bicarbonate (HCO3-); other electrolytes are potassium, calcium, and magnesium. |
| Primary electrolytes of intracellular fluid. | Cations: Potassium (K+), Magnesium (Mg2+) Anions: Phosphate (HPO4)(2-), Sulfate (SO4)(2-) |
| Osmosis | The movement of water across cell membranes, from the less concentrated solution to the more concentrated solution. |
| Solutes | Substances dissolved in a liquid. |
| Crystalloids | Salts that dissolve readily into true solutions - you can't differentiate between the solute and solvent molecules even at the microscopic level. |
| Colloids | Substances such as large protein molecules that do not readily dissolve to true solutions. |
| Solvent | The component of a solution that can dissolve a solute. |
| Osmolality | The concentration of solutes in the body fluids. Determined by the total solute concentration within a fluid compartment. |
| Isotonic | Solution that has the same osmolality as body fluids; Normal saline, 0.9% sodium chloride |
| Hypertonic | Solution that has a higher osmolality than body fluids; 3% sodium chloride |
| Hypotonic | Solutions that have a lower osmolality than body fluids; One-half Normal Saline, 0.45% Sodium Chloride |
| Osmotic pressure | The power of solution to draw water across a semipermeable membrane. |
| Colloidal Osmotic Pressure | Oncotic pressure; plasma proteins pull water from the interstitual space into the vascular compartment. Maintains vascular volume. |
| Diffusion | The continual intermingling of molecules in liquids, gases, or solids brought about by the random movement of the molecules. Molecules move from higher concentration to lower concentration. |
| Affects on the rate or speed of diffusion. | Size of the molecule: Large=Slow, Small=Fast Concentration of solution. Temp of the solution: Increase temp=Increase diffusion. |
| Filtration | Fluid and solutes move together across a membrane from on compartment to another. Movement from higher pressure to low pressure. |
| Filtration pressure | The pressure in the compartment that results in the movement of the fluid and substances dissolved in fluid, out of the compartment. |
| Hydrostatic pressure | Pressure exerted by a fluid within a closed system on the walls of a container in which it is contained. |
| Active transport | Use of metabolic energy moving substances across cell membranes from a less concentrated solution to a more concentrated one. A substance combines with a carrier molecule on outside surface of the cell membrane and they move to the inside surface of the cell membrane. |
| Amount of fluids needed per day to maintain balance. | 2,500 mL per day. The average adult drinks about 1500mL per day. |
| Amt of water content in foods contributing to fluid intake. | 750 - 1000 mL |
| Water content of fresh vegetables? fresh fruits? lean meats? | 90%, 85%, 60% respectively |
| Amt of water, as a by-product of food metabolism, ingested per day. | 200 mL |
| What is the primary regulator of fluid intake? | Thirst mechanism or center located in the hypothalamus of the brain. Triggered by osmotic pressure of body fluids, vascular volume, and angiotensin. |
| Angiotensin | A hormone released in response to decreased blood flow to the kidneys. |
| How long does it take for fluid to be absorbed and distributed throughout the body? | 30 minutes - 1 hour |
| Four routes of fluid output | Urine, Insensible loss, Noticeable loss through the skin, Loss through the intestines |
| Normal urine output for an adult is... | ...1400 to 1500 mL per day/24 hours |
| Insensible Loss | Occurs through skin(diffusion and perspiration) and lungs; usually goes unnoticed and cannot be measured. 300 - 400 mL per day |
| Loss through feces | 100 mL - 200 mL |
| Obligatory losses | Fluid losses required to maintain normal body function. Water loss through respirations, through the skin, and feces are obligatory losses. |
| The primary regulator of fluids and electrolyte balance. | Kidneys. Regulate the volume and osmolality of extracellular fluids by regulating water and electrolyte excretion. |
| How much plasma is filtered by the kidney - per day? | Filtration of 135 - 180 L of plasma/day, only about 1.5 L of urine is excreted. |
| Antidiuretic Hormone (ADH) | Regulates water excretion from the kidney. Synthesized in the anterior portion of the hypothalamus and acts on collecting ducts of nephrons. Osmolality increase=ADH produce to retain more water, urine output falls. Osmolality decrease=ADH is suppressed, collecting ducts become less permeable to water, urine output increases. |
| Syndrome Inappropiate ADH | Characterized by excessive release of antidiuretic hormone (ADH or vasopressin) from the posterior pituitary gland or another source. The result is hyponatremia and sometimes fluid overload. Maligant tumors, AIDS, head injury, or administration of certain drugs such as barbiturates or anesthetics can cause SIADH. |
| Renin-Angiotensin-Aldosterone System (RAAS) | Specialized receptors in the kidney nephrons that restores blood volume (and renal perfusion) through sodium and water retention. Renin is released, if blood flow to the kidney decreases, and activates RAAS. |
| RAAS causes blood pressure to increase. True of False | True. Angiotensin II is a potent vaso-active peptide which causes blood vessels to constrict, resulting in increased blood pressure. |
| Steps of RAAS system. | Blood flow to kidney decreases ==> Renin is released ==> Agiotensinogen is coverted to Agiotensin I ==ACE==> Agiotensin II ==> Sodium & Water retention. Angiotensin II also causes the release of Aldosterone ==> Na & H2O retention. |
| Atrial Natriutetic Factor | Released from cells in the atrium of the heart in response to excess blood volume and stretching of the atrial walls. Promotes sodium wasting, inhibits or decreases thirst. |
| Electrolytes are important for: (4) | Maintaining fluid balance. Contributing to acid-base regulation. Facilitating enzyme reactions. Transmitting neuromuscular reactions. |
| Two electrolytes not stored in the body. | Sodium (Na) and Chloride (Cl) Must be consumed daily to maintain normal levels. |
| The 7 major electrolytes of the body. | Sodium, Potassium, Calcium, Magnesium, Chloride, Phosphate, Bicarbonate |
| Most abundant cation in extracellular fluid. | Sodium. Normal serum sodium levels are 135 to 145 mEq/L. |
| Sodium functions | Regulating ECF volume and distribution Maintaining blood volume Transmitting nerve impulses and contracting muscles |
| Major cation of intracellular fluids. | Potassium. 3.5 to 5.0 mEq/L |
| The normal serum calcium levels. | 8.5 to 10.5 mg/dL |
| Normal serum levels of Mg, Cl, PO4 | 1.5 to 2.5 mEq/L, 95 to 108 mEq/L, 2.5 to 4.5 mg/dL |
| Isotonic imbalances | Occurs when water and electrolytes are lost or gained in equal proportions, so that the osmolality of body fluids remain constant. |
| Osmolar imbalances | Involve the loss or gain of only water, so the osmolality of the serum is altered. |
| Fluid Volume Deficit (FVD) | Isotonic loss. Hypovolemia - the body loses both water and electrolytes from the ECF in similar proportions. |
| Usual cause of FVD | Abnormal losses through skin, gastro intestinal tract or kidney Decreased fluid intake Bleeding Movement of fluid into third space |
| Fluid Volume Excess (FVE) | When the body retains both water and sodium in similar proportions. Hypervolemia |
| Usual causes of FVE | Excessive intake of NaCl Administering sodium containing infusions too rapidly Disease process - heart failure, renal failure, cirrhosis of the liver, Cushing's syndrome |
| Edema | Excess interstitial fluid. Hydrostatic capillary pressure is high, decreased plasma oncotic pressure, and increased capillary permeability. |
| Dehydration | Hyperosmolar imbalance; when water is lost leaving excess sodium. Serum osmalality and serum sodium levels increase. Water is drawn into the vascular compartment from the interstitial space. Hyperventilating, prolonged fever, diabetic ketoacidosis, enternal feedings w/ insufficient water intake can cause dehydration. |
| Overhydration | Hypo-osmolar imbalance; water is gained in excess of electrolytes. Water is drawn into the cell causing them to swell. |
| Hyponatremia | sodium deficit or serum sodium level of less than 135 mEq/L |
| Hypernatremia | excess sodium in ECF or serum sodium level greater than 145 mEq/L Osmotic pressure of ECF is increased, fluid moves out of the cell into the ECF |
| Hypokalemia | potassium deficit or a serum potassium level of less than 3.5 mEq/L |
| Hyperkalemia | potassium excess or a serum potassium level greater than 5.0 mEq/L; can lead to cardiac arrest |
| Hypocalcemia | <8.5 mg/dL or an ionized calcium level of <4.0 mg/dL |
| Hypercalcemia | >10.5 mg/dL or an ionized calcium level of >5.0 mg/dL ; caused by malignancy or prolonged immobilization |
| Hypomagnesemia | <1.5 mEq/L ; chronic alcholism is the most common cause |
| Hypermagnesemia | >2.5 mEq/L ; due to increas intake or decrease excretion |
| Hypochloremia | <95 mEq/L |
| Hyperchloremia | >108 mEq/L ; excess replacement of sodium chloride or potassium chloride |
| Hypophosphatemia | <2.5 mg/dL; glucose and insulin administration, parenteral nutrition(feeding through IV) |
| Hyperphosphatemia | >4.5 mg/dL ; tissue trauma, chemotherapy, renal failure |
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