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113 Cards in this Set
- Front
- Back
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- Anion
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ion that carries a negative charge
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- Cation
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ion that carries a positive charge
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- Electrolyte
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substance that dissociates in solution into ions (i.e. and molecule of NaCl becomes Na and Cl)
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- Nonelectrolyte
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substance that does not dissociate into ions in solution (i.e. glucose and urea)
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- Osmolality
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a measure of the total solute concentration per kilogram of solvent
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- Osmolarity
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a measure of the total solute concentration per liter of solution
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- Solute
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substance that is dissolved in a solvent
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- Solution
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homogenous mixture of solutes dissolved in a solvent
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- Water & electrolytes in the body
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60% of body weight
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o Older adults
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45-55%
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o Infant
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70-80%
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• Both of these groups are at a higher risk for_______.
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fluid-related problems
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- Body fluids constantly move
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distributed through different compartments
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- Intracellular Fluids
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fluid within the cell
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o 2/3rds of the body water is located within the cells
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40% of body weight
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- Extracellular Fluids
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fluid away from or outside of the cell
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o Interstitial Fluid
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in between cells
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o Intravascular
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inside blood vessel, but outside of cells (i.e. plasma, the fluid in blood)
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o Transcellular
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fluid located inside a cavity or structure (i.e. intraocular or CSF)
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- Water is necessary in the regulation of:
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body temperature, lubricating joints and membranes, and acts as a medium for food digestion
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Electrolytes
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Electrically charged particles or elements that dissolves or dissociates in water
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- Cation
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positively charged ions (sodium, potassium, calcium, and magnesium)
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- Anion
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negatively charged ions (bicarbonate, chloride, and phosphate)
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o Most proteins bear a ___________ charge and __________
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negative charge and are thus anions
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o ICF
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most prevalent cation is potassium, anion is phosphate
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o ECF
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most prevalent cation is sodium, anion is bicarbonate
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- Electrolytes move according to their:
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concentration and electrical gradients toward the areas of lower concentration and toward areas with the opposite charge
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- Osmosis
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movement of water between two compartments separated by a semipermeable membrane (a membrane permeable to water but not to a solute)
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o Movement of fluid from an area of less solute concentration to an area of high solute concentration
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more dilute (more water) compartment to more concentrated compartment (less water)
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o Stops when concentration differences:
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disappear or when hydrostatic pressure builds and is sufficient to oppose any further movement of water
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o Colloid Osmotic Pressure (oncotic)
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drawing power created by albumin; protein molecules attract water, pulling fluid from the tissue space to the vascular space
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o Hydrostatic Pressure
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the force within a fluid compartment; pressure of a volume of fluid against a wall (i.e. BP)
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- Diffusion
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the movement of molecules from an area of high concentration to one of low concentration
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o Net movement of molecules stops when:
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the concentrations are equal in both areas
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o Membrane but be:
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permeable
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o Facilitated diffusion
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moves molecules from an area of high concentration to one of low concentration; passive and requires not energy other than that of the concentration gradient
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- Filtration
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water and diffusible substances move together due to a difference in fluid pressure (i.e. urin formation via renal tubules and capsule)
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o Filtration is
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Movement from greater pressure to less pressure
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- Capillary hydrostatic pressure and interstitial oncotic pressure cause:
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the movement of water out of the capillaries. Plasma oncotic pressure and interstitial hydrostatic pressure cause the movement of fluid into the capillary.
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- Accumulation of fluid in the interstitium (edema) occurs if:
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venous hydrostatic pressure rises, plasma oncotic pressure decreases, or interstitial oncotic pressure rises.
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- Decreased oncotic pressure is seen when the plasma protein content is too low
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renal disorders, liver disease, malnutrition
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- Trauma, burns, and inflammation can damage capillary walls and allow plasma proteins to accumulate in the interstitium
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increased oncotic pressure draws fluid into the interstitium and holds it there
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- Fluid is drawn into the plasma space whenever there is an increase in the plasma osmotic or oncotic pressure
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administration of colloids, dextran, mannitol, or hypertonic solutions
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- Hypotonic Solution
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solution of lower osmotic pressure that regularly gives up fluid and water
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- Hypertonic Solution
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solution with higher osmotic pressure
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o Osmotic pressure
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the amount of pressure required to stop the osmotic flow of water; drawing power of a solution
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- Isotonic Solution
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solution of the same osmotic pressure; does not cause any molecule movement or shift of fluid
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- Fluid Intake
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regulated by thirst mechanisms (based on sodium levels in the blood)
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o Older adults experience a decrease in the thirst mechanism resulting in______
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decreased fluid intake
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o ADH
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stimulated by change of osmolality in blood or a decrease in circulating blood volume; increase in concentration stimulates pituitary to release ADH
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• ADH Acts in the:
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renal distal and collecting tubules causing water reabsorption
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o Aldosterone
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adrenal gland; increase in potassium stimulates aldosterone release
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• Potassium excites tissue
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too much can cause too much excitement and effect CO
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• Goal of aldosterone is to:
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attract and reabsorb sodium• Enhance sodium retention and potassium excretion
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• The secretion of aldosterone may be stimulated by
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decreased renal perfusion or decreased sodium delivery to the distal portion of the renal tubule
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o Renin
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kidneys; stimulates less kidney perfusion to decrease BP; released when kidney perfusion is decreased secondary to decrease in BP
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• Angiotensin I & II
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vasoconstriction, II stimulates aldosterone to contain Na and helps volume, BP & mentation to increase
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• ACE Inhibitors
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prevent vasoconstriction and aldosterone to increase blood volume action
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• Angiotensin
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is acted on by the rennin to form angiotensin I, which converts to angiotensin II, which stimulates the adrenal cortex to secrete alodosterone
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- Fluid Output Regulation
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exemplified by kidney
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o Skin, lungs and GI → insensible water loss
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500-600 ml/day; about 400 ml from the lungs • The book says normally 600-900 ml/day is lost
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• The amount of water loss is increased by accelerated ___________
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body metabolism, which occure with increased body temperature and exercise.
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o Sodium
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90% contained in ECF; main concern is water regulation
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• Function
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main cation of the ECF and plays a major role in maintaining the concentration and volume; primary determinant of ECF osmolality
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Na+
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• Normal value
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• Changes in the serum sodium level may reflect:
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a primary water imbalance, a primary sodium imbalance, or a combination of the two.
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• Hypernatremia
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causes hyperosmolality resulting in a shift of water out of the cells leading to cellular dehydration• Caused by excessive sodium intakeo IV Fluids: hypertonic NaCl, excessive isotonic NaCl, IV sodium bicarbo Hypertonic tube feedings without water supplementso Near-drowning in salt watero Inadequate water intake → unconscious or cognitively impaired individualso Excessive water loss → increased insensible water loss (high fever, heatstroke, prolonged hyperventilation), osmotic diuretic therapy, diarrheao Disease states → diabetes isipidus, primary hyperaldosteronism, Cushing syndrome, uncontrolled DM
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• Manifestations of hypernatermia:
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dehydration of cells (especially seen in brain cells)
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o Decreased ECF Volume
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restlessness, agitation, twitching, seizures, coma, intense thirst; dry, swollen tongue, sticky mucous membranes, postural hypotension, decreased CVP, weight loss, weakness, lethargy
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o Normal or Increased ECF Volume
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restlessness, agitation, twitching, seizures, coma, intense thirst, flushed skin, weight gain, peripheral and pulmonary edema, increased BP, increased CVP
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• Hyponatremia
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hyponatremia causes hypoosmolality with a shift of water into the cells• Caused by excessive sodium losso GI losses: diarrhea, vomiting, fistulas, NG suctiono Renal losses: diuretics, adrenal insufficiency, sodium wasting renal diseaseo Skin losses: burns, wound drainageo Inadequate sodium intake: fasting dietso Excessive water gain: excessive hypotonic IV fluids, primary polydipsiao Disease states: SIADH, heart failure, primary hypoalsodteronism
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• Hyponatermia Manifestations:
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cellular swelling and first manifested in CNS
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o Decreased ECF volume
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irritability, apprehension, confusion, dizziness, personality changes, tremors, seizures, coma, dry mucous membranes, postural hypotension, decreased CVP, decreased JV filling, tachycardia, thready pulse, cold and clammy skin
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o Normal or Increased ECF volume
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headache, apathy, confusion, muscle spasms, seizures, coma, nausea, vomiting, diarrhea, abdominal cramps, weight gain, increased BP, increased CVP
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o Potassium
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main electrolyte intracellularly – 98%
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• Function of Potassium
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critical for many cellular metabolic functions; neuromuscular and cardiac function, also regulates intracellular osmolality and promotes cellular growth
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• K+ Normal Value
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3.5-5.0 meq/L
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• 90% of potassium intake is eliminated by the:
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kidneys → if kidney function is significantly impaired, toxic levels of potassium maybe retained
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• Potassium moves into cells during the formation of
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new tissues and leaves the cell during tissue breakdown
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• Hyperkalemia increased cellular excitability• Caused by:
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o Excessive potassium intake → excessive or rapid parenteral administration, potassium-containing drugs, potassium-containing salt substituteo Shift of potassium out of cells → acidosis, tissue catabolism (fever, sepsis, burns), crush injury, tumor lysis syndromeo Failure to eliminate potassium → renal disease, potassium-sparing diuretics, adrenal insufficiency, ACE inhibitors (these drugs reduce the kidney’s ability to excrete potassium) o Can also be caused by giving expired blood (hemolysis)
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• Hyperkalemia Manifestations:
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Initially pt may experience cramping leg pain followed by weakness or paralysis of skeletal muscles o Irritability, anxiety, abdominal cramping, diarrhea, weakness of lower extremities, paresthesias, irregular pulse, cardiac arrest if hyperkalemia sudden or severeo ECG changes → tall, peaked T wave, prolonged PR interval, ST segment depression, loss of P wave, widening QRS, V fib, ventricular standstill o Hypokalemia → decreased cellular excitability • Caused by:
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• Hypokalemia Manifestations:
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• Fatigue, muscle weakness, leg cramps, N/V, paralytic ileus, soft, flabby muscles, paresthesias, decreased reflexes, weak, irregular pulse, polyuria, hyperglycemia• ECG changes → ST segment depression, flattened T wave, presence of U wave, ventricular dysrhythmias, bradycardia, enhanced digitalis effect
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o Fluid Volume Deficit
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can occur with abnormal loss of body fluids (i.e. diarrhea, fistula, drainage, hemorrhage, polyuria), inadequate intake, or a plasma-to-interstitial fluid shift
• NOT dehydration (dehydration refers to loss of pure water alone without corresponding loss of sodium) |
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• Decrease in circulating blood volume
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decrease in BP
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• Treatment goal
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correct underlying cause and replace both water and any needed electrolytes
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• Balanced IV solutions
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Lactated Ringers
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• NS is used when:
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rapid volume replacement is needed
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• Blood is indicated when:
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deficit is due to blood loss
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• Causes of Fluid imbalance:
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• Increased insensible water loss or perspiration, DI, osmotic diuresis, hemorrhage, vomiting, NG suction, diarrhea, fistula drainage, overuse of diuretics, inadequate fluid intake, third-space fluid shifts (burns, intestinal obstruction)
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• Fluid Imbalance Manifestations:
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• Restlessness, drowsiness, lethargy, confusion, thirst, dry mouth, decreased skin turgor, decreased cap refill, postural hypotension, increased pulse/CVP, decreased urine output, concentrated urine, increased RR, weakness, dizziness, weight loss, seizures, coma
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o Fluid Volume Excess
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may result from excessive intake of fluids, abnormal retention of fluids (i.e. heart failure, renal failure), or interstitial-to-plasma fluid shift
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• Treatment goal
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removal of fluid without producing abnormal changes in the electrolyte composition or osmolality of ECF
• Diuretics and fluid restriction • Restriction of sodium intake |
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• Causes of Fluid Volume Excess:
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• Excessive isotonic or hypotonic fluids, heart or renal failure, primary polydipsia, SIADH, cushing syndrome, long-term use of corticosteroids
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• Fluid Volume Excess Manifestations:
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• Headache, confusion, lethargy, peripheral edema, distended neck veins, bounding pulse, increased BP, increased CVP, polyuria (normal renal fxn), dyspnea, crackles, pulmonary edema, muscle spasms, weight gain, seizures, coma
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o Hyperosmolar
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body fluid that is too concentrated (lots of solute) – blood is so concentrated that cell shrinks by osmosis
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• DM (increased blood sugar)
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increased concentration
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• Give hypotonic solution
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½ NS
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o Hyposmolar
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water excess, cell can potentiall swell
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- Age
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very young are made of mostly fluids and dehydrate easily; very old can easily get dehydrated r/t decreased senses
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- Illness
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acute illness, surgery, burns, CHF, resp. disorders, renal disease
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- Environmental factors
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heat, extreme temperature, sweating- Diet- Lifestyle → smoking, alcohol intake- Medications
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Common Laboratory Studies
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- CBCo Hematocrit → amount of RBCs in whole blood; if pt is overly hydrated, hematocrit with decrease; dehydrated, hematocrit will increase- ABG- Serum Electrolytes Level
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• Why weight after urination?
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whatever is in the bladder is not part of your fluids → the bladder is a reservoir. However, the fluid in your stool is reabsorbed.
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- Enteral replacement of F&E loss
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GI, oral fluids, g-tube
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- Fluid Restriction vs. increase fluid intake
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if restriction, divide fluid throughout the day (more should be given throughout day rather than at night when pt is sleeping).
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o Increase in fluids
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monitor for signs of retention
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• Ex: hx of MI
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monitor pulmonary edema → backs up system and causes less cardiac output. Assess for crackles!
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- Parenteral replacement of F&E
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IV fluids
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- Medication
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lasix
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o Lasix
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increase potassium rich foods
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o Spironolactone
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watch potassium rich foods
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o Potassium sparing
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HR, ECG → increase HR, irregularities (arrhythmia could be indicator)
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o Potassium wasting
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slow HR
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