homeostasis
-proper function of all body systems; requires fluid and electrolyte balance
extracellular fluid ECF
-fluid outside the cells
-contains 1/3 of total body water
-includes the interstitial fluid, blood, lymph, bone, connective tissue water and transcellular fluids
intracellular fluid ICF
-fluid inside the cells
-2/3 of total body water
interstitial fluid
-fluid between cells, sometimes called the "third space
transcellular fluids
-the fluids in special body spaces and include cerebrospinal fluid, synovial fluid, peritoneal fluid, and pleural fluid
solvent
-water portion of fluids
solute
-particles dissolved or suspended in the water
-when expressed an overall electrical charge they become electrolytes
filtration
-movement of fluid through a cell or blood vessel membrane because of hydrostatic pressure differences on both sides of the membrane
hydrostatic pressure
-"water pushing" pressure because it is the force that pushes water outward from a confined space through a membrane
-amount of water in any body fluid space determines pressure
examples of hydrostatic pressure
-blood
blood pressure
-an example of a hydrostatic filtering force
an example of a hydrostatic filtering force
-moving whole blood from the heart to the capillaries where filtration occurs to exchange water, nutrients, and waste products between the blood and tissues
edema
-develops with changes in normal hydrostatic pressure differences
ex: patients with right sided HF
diffusion
-free movement of particles (solute) across a permeable membrane from an area of higher concentration to an area of lower concentration
-controls movement of particles in solution across variable membranes
-occurs more rapid when gradient is steeper (ball
concentration gradient
-this exists when two fluid spaces have different amounts of the same type of particles
diffusion
-important in transport of most electrolytes and other particles diffuse through cell membranes
ECF
-has ten times more sodium ions than ICF
sodium pumps
-cell membrane impermeability to sodium that move any extra sodium present inside the cell out of the cell against its concentration gradient and back into the ECF
-need "energy/ATP
glucose
-cannot enter most cell membranes without help of insulin
facilitated diffusion or facilitated transport
-diffusion across a cell membrane that requires assistance of a membrane altering system
osmosis
-movement of water only through a selectively permeable membrane
isotonic
Having the same solute concentration as another solution.
hypertonic
Having a higher concentration of solute than another solution.
hypotonic
Having a lower concentration of solute than another solution
osmosis and filtration
-act together at capillary membrane to maintain normal ECF and ICF volumes
thirst mechanism
-example how osmosis helps maintain homeostasis
feeling of thirst
-caused by an activation of cells in the brain that respond to changes in ECF osmolarity
fluid balance
-closely linked to and affected by electrolyte concentrations
normal sodium Na
136-145 mEq/L
normal potassium K
3.5-5.0 mEq/L
normal calcium Ca
9.0-10.5 mg/dL
normal chloride Cl
98-106 mEq/L
normal magnesium Mg
1.3-2.1 mEq/L
normal phosphorus P
3.0-4.5 mg/dL
400-600mL
-the minimum amount of urine per day needed to excrete toxic waste products
fluid intake
-measurable: oral fluids, parenteral fluids, enemas, irrigation fluids
-not measurable: solid food, metabolism
fluid loss/output
-measurable: urine, emesis, feces, drainage from body cavities
-not measurable: perspiration, vaporization through the lungs
insensible water loss
-water loss from the skin, lungs, and stool
-normal loss is 500-1000mL/day
-at risk for increased loss are mechanically ventilated and those with rapid respirations
aldosterone
-hormone secreted by the adrenal cortex when sodium levels in ECF are low
-prevent sodium and water loss
antidiuretic hormone ADH or vasopressin
-produced from the posterior pituitary gland and controlled by the hypothalamus in response to changes in blood osmolarity
-more water is reabsorbed decrease blood osmolarity
natriuretic peptides NPs
-hormone secreted by cells that line the atria and ventricle of the heart
-secreted in response to increase in blood volume and BP which stretch the heart tissue
-opposite of aldosterone; sodium reabsorption is stopped and increase in urine output
blood (plasma) volume and ICF
-most important to keep in balance
kidneys
-maintain BP and perfusion to all tissues and organs and monitor BP, blood volume, blood oxygen levels, and blood osmolarity
-when they sense a low parameter they secrete renin
renin
-sets into motion a group of hormonal and blood vessel responses to ensure that blood pressure is raised back to normal
-enzyme that activates blood proteins: angiotensin
angiotensin 1
-is activated angiotensinogen which is relatively weak and and has little action
-acted on by another enzyme angiotensin-converting enzyme which converts this to angiotensin 2
angiotensin II
-act to increase BP and blood volume
-vasoconstricts small arteries and veins, arterioles that feed the kidney decreasing urine output
-causes adrenal glands to secrete aldosterone reabsorbing sodium and water
renin angiotensin II pathway
-greatly stimulated with shock, or when stress response is stimulated
-manage hypertension
drugs that manage hypertension
-ACE inhibitors and ARBS
ACE inhibitors
-disrupt the renin angiotensin pathway by reducing the amount of ACE made so less angiotensin 2 is present
-with less angiotensin 2 there is less vasoconstriction, less aldosterone production and greater excretion of water and sodium in urine
angiotension receptor blockers ARBs
-disrupt renin angiotensin II pathway by blocking the receptors that bind with angiotensin 2 so that tissues cannot respond to it and BP is lowered
blood pressure
-a decrease in blood volume always results in a decrease in_____and vise versa
dehydration
-fluid intake or fluid retention does not meet body's fluid needs resulting in fluid volume deficit
-water is only lost from ECF
-hemoconcentration
older adults and dehydration
-more at risk because they have less total body water
-have decreased thirst sensation
-difficulty walking/motor skills to obtain fluids
-take meds: diuretics, anti-HTN, laxatives
isotonic dehydration
-most common type of fluid loss problem
-water loss with electrolyte loss
causes of dehydration
-hemorrhage
-vomiting and diarrhea
-profuse salivation
-fistulas
-ileostomy
-profuse diaphoresis
-burns
-severe wounds
-long term NPO status
-diuretic therapy
-GI suction
-hyperventilation
-renal failure (early phase)
-diabetes insipidus
-difficulty swall
causes of fluid overload
-excessive fluid replacement
-kidney failure (late phase)
-HF
-long term corticosteroid use
-SIADH
-psychiatric disorders with polydipsia
-water intoxication
changes in daily weights
-best indicator of fluid loss or gain
-weight change of 1 pound corresponds to a fluid volume change of about 500mL
cardiovascular changes with dehydration
-increase HR
-weak peripheral pulses
-decreased BP greater decrease in systolic
-hypotension more severe sitting/lying down (orthostatic or postural hypotension)
-light headedness and dizziness (increase risk for falls)
-neck veins distended in supine
-ne
respiratory changes with dehydration
-increase respiratory rate
skin changes with dehydration
-assess skin and mucous membranes for color, moisture and turgor
-poor turgor
-dry and scaly
-not moist mucous membranes
neurologic changes with dehydration
-alterations of mental status especially confusion
-low grade fever; at risk for dehydration with temp of 102F for longer than 6 hours
500mL of body fluid is lost
-for every degree (celsius) increase in body temp above normal a minimum of an additional
confusion
-may be first indicator of fluid imbalance in older adults
kidney changes with dehydration
-concentrated urine
-increase specific gravity more than 1.030
-dark amber color and strong odor
cause for concern
-urine output below 500mL/day w/o kidney disease
interventions for dehydration
-patient safety
-fluid replacement
-drug therapy
mild to moderate dehydration
-corrected with oral fluid therapy
severe or life threatening dehydration or cannot tolerate oral fluids
-corrected with IV fluid therapy
isotonic solutions
-0.9% NS
-D5W: 5% dextrose in water
-5% dextrose in 0.225% NS
-ringers lactate
hypotonic solutions
-0.45% NS
hypertonic solutions
-D10W: 10% dextrose in water
-5% dextrose in 0.9% NS
-5% dextrose in 0.45% NS
-5% dextrose in ringers lactate
pulse rate/quality and urine output
-two most important areas to monitor during rehydration
fluid overload
-overhydration
-an excess of body fluid
-hemodilution
cardiovascular changes with fluid overload
-increased pulse rate
-bounding pulse quality
-full peripheral pulse
-elevated BP
-decreased pulse pressure
-elevated CVP
-distended neck and hand veins
-engorged varicose veins
-weight gain
respiratory changes with fluid overload
-increased respiratory rate
-shallow respirations
-increased dyspnea with exertion or in supine
-moist crackles on auscultation
skin and mucous membrane changes with fluid overload
-pitting edema in dependent areas
-skin pale and cool to touch
neuromuscular changes with fluid overload
-altered LOC
-headache
-visual disturbances
-skeletal muscle weakness
-paraesthersias
GI changes with fluid overload
-increased motility
-enlarged liver
interventions for fluid overload
-patient safety (priority)
-drug therapy: diuretics
-nutrition therapy: Na and water restriction
-monitoring
patient with SIADH and diuretics
-conivaptan or tolvaptan
call health care provider
-gain 3lbs in a week or 1-2lbs in 24 hours
cations
-positive charge
anions
-negative charge
older adults and electrolyte imbalances
-at greatest risk as a result of age-related organ changes
-have less total body water
-meds that effect electrolytes
sodium
-in the ECF high low in ICF
sodium
-water follows
low sodium levels
-inhibit (stop) the secretion of ADH and NP and trigger aldosterone to increase sodium
hyponatremia manifestations
-sudden onset of acute confusion
-muscle weakness and diminished deep tendon reflexes
-increased motility causing nausea, diarrhea and abdominal cramping, hyperactive bowel tones
-hypovolemia: rapid, weak thready pulse
-peripheral pulses hard to palpate
-
respiratory effectiveness
-if muscle weakness is present with hyponatremia immediately check
interventions for hyponatremia
-stop diuretics
-IV saline or hypertonic saline
-with SIADH give conivaptan or tolvaptan
-increase oral sodium intake
hypernatremia manifestations
-altered mental status
-short attention span and gets agitated or confused
-possible seizures
-lethargic, drowsy
-muscle twitching, irregular muscle contractions then become weaker
-absent deep tendon reflexes
-increased HR, reduced peripheral pulses, hyp
interventions for hypernatremia
-hypotonic IV infusions 0.225% NaCl
-fluid replacement
-diuretics
-adequate water intake
-restrict sodium
potassium
-high in ICF low in ECF
foods high in potassium
-meat
-fish
-most vegetables and fruit
foods low in potassium
-eggs
-bread
-cereal grains
hypokalemia manifestations
-can be life threatening
-muscle weakness
-shallow respirations: assess respiratory q2hrs
-hyporeflexia, severe: paralysis
-thready weak pulse
-orthostatic hypotension
-rapid or slow pulse
-acute confusion, lethargy
-decreased peristalsis, hypoactive bowe
drugs that cause hypokalemia
-diuretics
-corticosteriods
-digitalis
priority nursing interventions for hypokalemia
-ensure adequate oxygenation, patient safety from falls, prevent injury from administering potassium and monitor response
respiratory status
-assess first in any patient who might have hypokalemia
interventions for hypokalemia
-potassium replacement (IV if severe) never given IM or SQ
-potassium sparing diuretics: spionolactone, triamterene, amiloride
-eat potassium foods
-safety measures, fall precautions
-assess respiratory hourly
IV potassium
-1 mEq of potassium to 10mL of solution
-maximum is 5-10 mEq/hr never exceed 20!
infiltration of IV with potassium occurs
-stop the IV solution immediately and remove the IV and notify the health care provider or rapid response team and document
complications hyperkalemia
-complete heart block
-v-fib
-asystole
causes hyperkalemia
-transfusion of blood
-adrenal insufficieny, addisons disease
-ACE inhibitors
hyperkalemia manifestions
-bradycardia
-hypotension
-peaked T waves, prologned PR, absent P, wide QRS
-ectopic beats
-early: muscle twitching, tingling, burning and numbness in hands, feet, around mouth
-late: weakness followed by flaccid paralysis
-increased motility
interventions for hyperkalemia
-stop potassium infusions and oral
-restricted potassium diet
-diuretics, furosemide, kayexalate
-dangerously high may need dialysis
-insulin and glucose IV, hypertonic
-avoid salt substitues
notify health care provider or rapid response team
-heart beat falls below 60bpm or T waves become spiked
calcium
-absorption requires form of vitamin D
-stored in the bones
-PTH increase this
-thyrocalcitonin decrease this
-loss of this occurs when absorption from the GI tract slows or is lost from the body
hypocalcemia manifestations
-charley horses
-paraesthesias: tingling and numbness (most common)
-painful cramps and twitching
-positive trousseaus and chvosteks signs
-weak thready pulse
-HR may be low or slightly high
-hypotension
-prolonged ST and QT
-increased peristalsis
-weaker
interventions for hypocalcemia
-calcium replacement oral or IV
-aluminum hydroxide and vitamin D
-possibly muscle relaxants and magnesium sulfate
-high calcium food
-quiet calm environment
-fragile so use a lift sheet
hypercalcemia
-causes faster clotting time
-mild: increase HR and BP
-severe: slows HR
-check for dysrhythmias
-muscle weakness and decreased deep tendon reflexes
-altered LOC
-decreased peristalsis
-N/V, constipation, abdominal pain
-hypoactive bowel tones
-abdominal
interventions for hypercalcemia
-stop any calcium or vitamin D, stop thiazides
-IV NS for fluid
-use lasix and calcium chelators (penicillamine, plicamycin)
-phosphorus, calcitonin, biphosphates, NSAIDs
-dialysis
-cardiac monitoring
phosphorus
-major anion in ICF
-80% is in the bones
-needed to activate ATP
foods with phosphorus
-meat, fish, dairy and nuts
hypophosphatemia manifestations
-decreased SV and CO
-decreased peripheral pulses
-weak heart contractions
-muscle weakness leading to rhabdomyolysis
-respiratory failure
-irritability
chronic hypophosphatemia
-most evident in skeletal system
-decreased bone density
-bone calcium loss
interventions for hypophosphatemia
-oral replacement of phosphorus and vitamin D
-IV phosphorus when below 1mg/dL
-increase foods with phosphorus and decrease in calcium
drugs that promote phosphorus loss
-antacids
-osmotic diuretics
-calcium supplements
foods to avoid with hypophosphatemia
-milk
-cheese
-yogurt
-collard greens
-rhubarb
foods to eat with hypophosphatemia
-fish
-beef
-chicken
-pork
-organ meats
-nuts
-whole grain breads and cereals
hyperphosphatemia
-high levels are well tolerated by most body systems
-kidney disease, cancer treatments, hypoparathyroidism
-hypocalcemia
magnesium
-forms a cation when dissolved in water
-60% stored in bones
-critical for muscle contraction
-need 300mg/day
hypomagnesemia manifestations
-diuretics can cause this
-hyperactive deep tendon reflexes
-numbness and tingling
-painful muscle contractions
-positive chvosteks and trousseaus (hypocalcemia)
-skeletal muscle weakness
-tetany and seizures
-depression, psychosis, confusion
-reduced mot
interventions for hypomagnesemia
-stop diuretics (loop, osmotic), aminoglycoside antibiotics
-magnesium sulfate IV because IM causes pain
-watch for diarrhea and treat hypocalcemia too
hypermagnesemia manifestations
-bradycardia
-peripheral vasodilation
-hypotension and possible cardiac arrest
-drowsy and lethargic
-absent/reduced deep tendon reflexes
-weak voluntary skeletal muscle contractions
-respiratory failure and death from weak respiratory muscles
interventions for hypermagnesemia
-discontinue magnesium
-w/o kidney failure give magnesium-free IV fluids
-calcium
-lasix (high ceiling loop diuretic)
chloride
-important in the formation of hydrochloric acid in the stomach
-bicarbonate exchanges with this
-enters with dietary intake
-usually result in loss of other electrolytes to be decreased
-interventions are correcting the electrolyte imbalance