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109 Cards in this Set
- Front
- Back
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Homeostasis
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the state of equilibrium in the internal environment of the body, naturally maintained by adaptive responses that promote healthy survival
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intracellular fluid
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2/3 of the body water is located within cells
appox 40% of body weight |
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extracellular fluid
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20% of total weight
consists of interstitial fluid and lymph; and a small amout of fluid contained within specialized cavities: gi tract, pleural, synovial, peritoneal, csf |
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interstitial fluid
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composed of the fluid in the interstitium (space between cells)
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lymph
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fluid in blood plasma
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transcellular fluid
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in the specialized cavities
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Functions of body water
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transporting nutrients, electrolytes, and oxygen to cells and carrying waste away from cells
regulation of body temperature lubricates joints and membranes medium for digestion |
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electrolytes
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substances whose molecules dissociated, or split, into ions, when placed in water
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cations
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positively charged ions
sodium, potassium, calcium, magnesium |
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anions
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negatively charged ions
bicarbonate HCO3- chloride cl- phosphate po4 3- |
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Most prevalent cation in the ICF
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potassium, with small amounts of magnesium and sodium
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the prevalent ICF anion
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phosphate, with some protein and a small amount of bicarbonae
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in the ECF, the main cation
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sodium, with small amounts of potassium, calcium and magnesium
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the primary ECF anion
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Chloride, with small amounts of bicarbonate, sulfate and phosphate
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Diffusion
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movement of molecules from area of high concentration to low concentration
movement stops when the concentrations are equal in both areas |
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facilitated diffusion
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moves molecules from are of high concentration to low concentration
passive and requires no energy Glucose transport into the cell is an example carrier molecule on most cells that increases or facilitates the rate of diffusion of glucose |
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active transport
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molecules move against the concentration gradient
external energy required sodium moves out of the cell and potassium moves in (sodium-potassium pump) requires ATP |
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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)
requires no outside energy sources and stops when the concetration difference disappears or when hydrostatic pressure builds |
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osmotic pressure
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the amount of pressure required to stop the osmotic flow of water
determined by the concetration of solutes in solution |
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Isotonic
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fluids with the same osmolality as the cell interior
ECF and ICF are normally isotonic to each other |
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Hypotonic
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solutions in which the solutes are less concentrated than the cells
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Hypertonic
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solutions in which the solutes are more concentrated than the cells
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If a cell is surrounded by a hypotonic fluid...
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water moves into the cell, causing it to swell and possibly burst
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if a cell is surrounded by a hypertonic fluid...
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water leaves the cell to dilute the ECF; the cell shrinks and eventually might die
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hydrostatic pressure
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the force within a fluid compartment
the blood vessels, its the blood pressure generated by the contraction of the heart |
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Oncotic Pressure
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colloidal osmotic pressure -
osmotic pressure exerted by colloids in solution |
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the major colloid in the vascular system
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protein - it contributes to the total osmotic pressure
protein molecules attract water, pulling fluid from the tissue space to the vascular place |
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normal movement of fluid between capillary and interstitium...
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the amound and direction of movement determined by
1) capillary hydrostatic pressure 2) plasma oncotic pressure 3) interstitial hydrostatic pressure 4) interstitial oncotic pressure |
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what causes water out of the capillaries?
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capillary hydrostatic pressure and interstitial oncotic pressure
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what causes movement of fluid into the capillary?
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plasma oncotic pressure and interstitial hydrostatic pressure
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accumulation of fluid in the interstitium (edema)occurs when...
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hydrostatic pressure rises
plasma oncotic pressure decreases interstitial oncotic pressure rises |
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elevation of venous hydrostatic pressure
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increasing pressure at the venous end of the capillary inhibits fluid movement back into the capillary
caused by: fluid overload, heart failure, liver failure, obstructinof venous return to the heart, venous insufficiency |
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decrease in plasma oncotic pressure
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fluid remains in the interstitium if the plasma oncotic pressure is too low to draw fluid back into the capillary
seen when plasma protein content is too low caused by: excessive protein loss (renal disorders), deficient protein synthesis (liver disorders), deficient protein intake (malnutrition) |
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elevation of interstitial oncotic pressure
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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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fluid is drawn into the plasma space whenever...
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there is an increase in the plasma osmotic or oncotic pressure
can happen with admin of colloids, dextran, mannitol, or hypertonic solutions |
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increased ECF osmolality
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(water deficit)
pulls water out of the cells until the two compartments are similar assoc with symptoms that result in cell shrinkage |
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decreased ECF osmolality
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(water excess)
develops as a s result of gain or retention of water excess so cells swell Primary symptoms are neurologic as a result of brain cell swelling as water shifts into the cells |
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water balance is maintained by...
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the balance of water intake and excretion
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regulation of water balance
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hypothalamic regulation
pituitary regulation adrenal cortical regulation renal regulation cardiac regulation GI regulation insensible water loss |
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a body fluid deficit, or increase in plasma osmolality is sensed by...
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osmoreceptors in the hypothalamus, which stimulates thirst and antidiuretic hormone (ADH) release.
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pituitary regulation
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under hypothalamic control, the posterior pituitary releases ADH, which regulates water retention by the kidneys
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syndrome of inappropriate antidiuretic hormone secretion
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causes include abnormal ADH production in the CNS and certain malignancies (brain tumors, brain injury, small cell lung cancer)
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diabetes insipidus
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produced by reduction in the release or action of ADH
exhibits extreme polyuria and polydipsia. dehydration and hypernatremia develop if water losses aren't replaced |
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Adrenal cortex regulation
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glucocorticoids and mineralcorticoids secreted by the adrenal cortex help regulate water and electrolytes
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glucocorticoids
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have an antiinflammatory effect and increase serum glucose levels
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mineralcorticoids
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(aldosterone) enhance sodium retention and potassium excretion
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Cortisol
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Most abundant glucocorticoid
has both glucocortoid (glucose-elevating and antiinflammatory) and mineralcorticoid (sodium retention) effects |
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Aldosterone
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mineralocorticoid with potent sodium-retaining and potassium-excreting capability
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Primary organs for regulating fluid and electrolyte balance
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Kidneys -- through adjustments in urine volume
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severely impaired kidneys
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cannot maintain fluid and electrolyte balance
results in edema potassium and phosphorus retention acidosis |
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cardiac regulation
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cardiomyocytes produce hormones (ANP and BNP) in response to increased arterial pressure (increased volume) and high serum sodium
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Natriuretic peptides
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including Atrial natriuretic peptide (ANP) and b-type natriuretic peptide (BNP)
natural antagonists to the RAAS suppress secretion of aldosterone, renin, and ADH and the action of angiotensin II |
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insensible water loss
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invisible vaporization from the lungs, skin, assists in regulating body temp
600-900ml/day is lost |
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insensible perspiration
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only water is lost
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sensible perspiration
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excessive sweating
caused by fever or high environmental temperatures may lead to large losses of water and electrolytes |
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gerontologic considerations
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structural changes to the kidney and decrease in renal blood flow cause decrease in glomerular filtration rate, decreased creatinine clearance, the loss of the ability to concentrate urine and conserve water
not as much renin and aldosterone increase in ADH and ANP |
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patient with prolonged nasogastric suction will..
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lose sodium, potassium, hydrogen and chloride
may result in deficiency of sodium and potassium, fluid volume deficit and metabolic alkalosis |
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causes of fluid volume deficit
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increase insensible water loss or perspiration
diabetes insipidus osmotic diuresis hemorrhage GI losses - vomiting, NG suction, diarrhea, fistula drainage overuse of diuretics inadequate fluid intake thrid space fluids - burns, obstruction |
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causes of fluid volume excess
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excessive isotinic or hyptonic IV fluids
heart failure renal failure primary polydipsia SIADH cushing syndrome long term use of corticosteroids |
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ECF volume deficit - clinical manifestations
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restlessness, drowsiness, lethary, confusion
thirst, dry mouth decreased skin turger reduced capillary refill postural hypotension increased pulse reduced CVP reduced urine output concentrated urine weakness, dizziness weight loss seizures, coma |
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ECF volume excess - clinical manifestations
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headache, confusion, lethargy
peripheral edema distended neck veins bounding pulse increased BP increased CVP polyuria (w/normal renal func) muscle spasms weight gain seizures, coma |
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Fluid volume excess - treatment
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goal is removal of fluid without upsetting electrolyte balance or osmolaity in ECF
diuretics, fluid restriction, Na restriction |
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fluid volume deficit - treatment
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correct underlying cause
balanced IV solutions (lactated ringers) isotonic sodium chloride blood admin if due to blood loss |
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hyponatremia
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na < 135 mEq/L
excessive sodium loss inadequate sodium intake |
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hyponatremia with decreased ecf volume - signs
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irritability, apprehension, confusion, dizziness, personality changes, tremors, seizures,coma, dry mucous membranes, postural hypotension, refuced CVP, decreased jugular venous filling, tachycardia, thready pulse, cold and clammy skin
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hyponatremia with normal/increased ecf volume - signs
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headache, apathy, confusion, muscle spasms, seizures, coma, nausea, vomiting, diarrhea, ab cramps, weight gain, increased bp, increased CVP
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hypernatremia
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Na >145
excessive sodium intake inadequate water intake excessive water loss diabetes insipidus |
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hypernatremia with decreased ecf volume - signs
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restlessness, agitation, twitching, seizures, coma, intense thirst, dry and swollen tongue, sticky mucous membranes, postural hypotension, decreased CVP, wweight loss, weakness, lethargy
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hypernatremia with noraml,increased ecf volume - signs
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restlessness, agitation, twitching, seizures, coma, intense thirst, flushed skin,weight gain, edema, increased BP, incrased CVPO
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hypernatremia - treatment
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oral fluid replacement
IV soln of 5% dextrose in water or hypotonic saline dilute sodium excess with sodium-free iv fluids like 5% dextrose in water, and diuretics |
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hyponatremia - treatment
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fluid restriction
small amts of iv hypertonis saline solution (3% nacl) if severe |
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hypernatremia nursing implementation
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give hypotonic or isotonic
restrict sodium encourage water monior LOC maintain client safety provide oral hygiene monitor I&Os daily weights seizure precautions |
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Hypokalemia - causes
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diarrhea, vomiting, fistulas, ng suction, diuretics, hyperaldosteronism, mg depletion, dialysis
increased insulin, alkalosis, tissure repair, stress starvation, low K diet |
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hypokalemia - manifestation
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fatigue
muscle weakness, leg cramps nausa, vomiting, decreased reflexes soft, flabby muscles paresthesias weak, irregular pulse polyuria hyperglycemia |
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hypokalemia - ecg changes
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st segment depression
flattened T wave Presence of U wave Ventricular dysrhythmisa bradycardia enhanced digitalis effect |
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hyperkalemia - causes
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excessive/rapid parenteral admin
potassium containing drugs salt substitutes acidosis tissue catabolism (fever, sepsis) crush injury tumor lysis syndrome renal disease potassium sparing diuretics adrenal insufficiency ace inhibitors |
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hyperkalemia - manifestations
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irritablility
anxiety abdominal cramping, diarrhea weakenss lower extremities paresthesias irregular pulse cardiac arrest if sudden or severe |
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hyperkalemia - ECG
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Tall, peaked T wave
prolonged PR interval ST segment depression loss of P wave Widening of QRS ventricular fibrillation ventricular standstill |
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hyperkalemia - interventions
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eliminat oral and parenteral K intake
increase elimination of K via diuretics, dialysis, increased fluid intake force potassium from ECF to ICF with insulin admin calcium gluconate IV |
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hypokalemia - interventions
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give potassium chloride supplements
increase K in diet |
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KCL
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except in severe deficiencies, KCL is never given unless there is a urine ouput of at least 0.5ml/kg of body weight per hour
KCL supplements added to IV should never exceed 60meq/L preferred is 40 rate of KCL iv admin should not exceed 10-20 meg/hour to prevent hyperkalemia and cardiac arrest |
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hypocalcemia - causes
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chronic renal failure
elevated phosporus primary hypoparathyroidism vitamin D deficiency mg deficiency acute pancreatitis loop diuretics chronic alcoholism decreased serum albumin |
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hypocalcemia - manifestations
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easily fatigabliltiy
depression, anxiety, confusion numbness, tingling extremities hyperreflexia muscle cramps chvostek's sign trousseau's sign laryngeal spasm tetany, seizures |
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hypocalcemia - ECG
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elongation of ST segment
prolongation of QT inteval ventricular tachycardia |
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hypercalcemia - causes
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multiple myeloma
malignancies with bone metastsis prolonged immobilization hyperparathyroidism vitamin d overdose thiazie diuretics milk alkali syndrome |
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hypercalcemia - manifestions
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acidosis
lethary, weakness depressed reflexes decreased memory confusion, anorexia, nausea, vomiting bone pain, fractures polyuria, dehydration nephrolitiassis stupor, coma |
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hypercalcemia - ECG
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shortened ST segment
shortened QT interval ventricular dysrhythmia increased digitalis effect |
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hypercalcemia - interventions
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loop diuretic
isotonic solution |
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hypocalcemia - interventions
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oral or iv calcium supplements
not given IM because it may cause severe local reactions, burning, necrosis and tissue sloughing calcium gluconate IV if severe |
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hypophosphatemia - causes
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malaborption
glucose admin parenteral nutrition alcohol withdrawl phosphate binding antacids recovery from diabetic ketoacidiosis respiratory alkalosis |
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hypophosphatemia - manifestations
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muscle weakness
cns dysfunction,, confusion renal tubular wasting of mg, ca ,hco3 cardia problems osteomalacia rhabdomyolysis |
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hyperphosphatemia - causes
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renal failure
chemotherapeutic agents enemas containing phosphorus excessive ingestion large vit d intake hypoparathyroidism |
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hyperphosphatemia - manifestations
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hypocalcemia
muscle problems, tetany deposition of calcium-phosphate precipitates skin,, soft tissue, corneas, viscer, blood vessels |
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hypomagnesemia - causes
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diarrhea
vomiting chronic alcoholism impaired gi absorption malabsorption prolonged malnutrition large urine output ng suction poorly controlled DM hyperaldosteronism |
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hypermagnesemia - causes
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renal failure
excessive admin of mg for eclampsia adrenal insufficiency |
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pH and hydrogen ion concentration
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increase in H leads to acidity
decrease in H leads to alkalinity |
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buffer system
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the fastest acting system and the primary regulator of acid-base balance
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buffers
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act chemically to change strong acids into weaker acids or to bid acids to neutralize their effect
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respiratory system maintain's normal pH by
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excreting CO2 and water
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renal system maintains normal pH by
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secretes small amounts of free hydrogen into renal tubule
combination of H with ammonia to form ammonium excretion of weak acids |
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respiratory balances affect
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carbonic acid concentrations
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metablic imbalances affect
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base bicarbonate
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respiratory acidosis
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CO2 retention from hypoventilation
compensatory response to HCO3 retention by kidney plasma ph low PaCO2 increases HCO3 normal (uncompensated) HCO3 increased (compensated) urine ph low (uncompensated) |
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respiratory alkalosis
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increased CO2 from hyperventilation
HCO3 excretion plasma ph increases PaCO2 decreases HCO3 normal (uncompensated) HCO3 decreased (compensated) urine ph increases (compensated) |
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metabolic acidosis
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CO2 excretion from lungs
fain of acid plasma ph down PaCO2 normal (uncompensated) PaCO2 down (compensated) HCO3 down Urine ph down (compensated) |
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metabolic alkalosis
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loss of acid
CO2 retention plasma ph up PaCO2 normal (uncompensated) PaCO2 up (compensated) HCO3 up Urine pH up (compensated) |
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hypotonic solution
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provides more water than electrolytes, diluting the ECF
0.45% saline provides free water with NaCl for hypotonic fluid losses provides no calories used as maintenance solution |
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isotonic solution
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expands only the ECF
no net loss or gain 0.9% saline 5% in 0.225% dextrose in saline lactated ringers 5% dextose in water |
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hypertonic solution
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initially raises the osmolality of ECF and expands it
10% dextrose in water 3% saline 5% in 0.45% dextrose in saline 5% in 0.9% dextrose in saline |
