NursingTest 9 Flashcards
approximately __% of a young adult’s body weight is water
60%
Elderly 50%
Infants 70-80%
Women have less body water and have more fat than men
define electrolytes
chemicals that can conduct electricity when dissolved in water
define extracellular fluid and the 3 types
- -fluid outside the cells
- -interstitial fluid, intravascular fluid, and transcellular fluid
primary control of water in the body is:
pressure sensors in the vascular system
define diuretic
substance that causes the kidneys to excrete more fluid
what does ADH do?
- -opposite of diuretic
- -causes the kidneys to retain fluid
what is passive transport and the 3 types of passive transport systems
- -no energy is expended specifically to move the substances
- -general body movements aid in passive transport
–diffusion, filtration, osmosis
define diffusion
- –process in which the substance moves from an area o higher concentration to an area of lower concentration
- -body movement assist
define filtration
- -movement of both water and smaller molecules through a semipermeable membrane
- -promoted by hydrostatic pressure differences between areas
define hydrostatic pressure
- -sometimes called water-pushing pressure
- -the force that the water exerts
- -important for the movement of water, nutrients, and waste products in the capillaries
define osmosis
- -movement of water from an area of lower substance concentration to an area of higher concentration
- -substances exerts an osmotic pressure sometimes called water-pulling force
define osmolarity
the concentration of the substances in the body’s fluids
–normal is between 270 and 300 mOsm/L
define isotonic
fluid has same osmolarity as the blood
define hypotonic
solution has lower osmolarity than blood
–when hypotonic solution is given, water in the solution leaves the blood and other ECF areas and enters the cells
define hypertonic
- -solutions exert grater osmotic pressure than blood
- -when given water leaves the cells and enters the bloodstream and other ECF spaces
water is very important to the body for:
cellular metabolism
blood volume
body T regulation
solute transport
older adults are more prone to fluid deficits because:
- –diminished thirst reflex
- -kidneys do not function as effectively
- -increase in body fat (fat doesn’t contain water)
what’s the difference between sensible and insensible fluid loss
- -sensible=those of which the person is aware (urination)
- -insensible=may occur without the person recognizing the loss (perspiration, respiration, feces elimination)
most common form of dehydration results from:
loss of fluid from the body, resulting in decreased blood volume. this decrease is referred to as hypovolemia
define hypovolemia
- -decreased blood volume
- -occurs when pt is hemorrhaging or when fluids from other parts of the body are lost (vomiting, diarrhea, wounds, sweating)
- -can also occur when fluid from the intravascular space moves into the interstitial fluid space
define third spacing
- -when fluid from the INTRAvascular space moves into the INTERstitial fluid space
- -examples when this occurs: burns, liver cirrhosis, extensive trauma
common causes of dehydration
cecostomy diabetes insipidus diarrhea diuretic therapy draining abscesses draining fistulas fever frequent enemas GI suction hemorrhage ileostomy NPO status sweating severely draining wounds systemic infection vomiting
high risk pts for dehydration
infants
children
elderly
sings and symptoms of dehydration
- -initial symptom is thirst
- -weak rapid pulse (hear pumps the remaining blood faster, but not as powerfully)
- -low blood pressure
- -decreased tear formation, dry skin, dry mucous membrane (body pulls water into the vascular system from other areas)
- -poor skin turgor
- -T increases (body less able to cool itself through perspiration)
- -urine output decrease, becomes concentrated
- -urine may be darker
- -may become constipated (intestines absorb more water from feces)
- -weight loss (a pint of water is aprox 1 lb.)
manifestation of dehydration is older adults are different than younger ones. what are some sings
altered mental status
lightheadedness
syncope (loss of consciousness caused by low BP)
diagnostic tests signs of pt with dehydration
- -elevated BUN
- -elevated hematocrit
- -specific gravity of urine increases
- -there is less water in proportion to the solid substances being measured. kidneys attempt to conserve water
when do you check skin turgor on elderly
forehead or sternum
usually retains elasticity, so more reliable places
best practice recommendations for maintaining oral hydration in older ppl
- -have fluid intake sheet
- -urine specific gravity may be most accurate determination
- -dry furrowed tongue and mucous membranes, sunken eyes, confusion, and upper body weakness are indicators
- -regularly offer fluids
- -offer fluids with meds
define hypervolemia
excess fluid in the intravascular space
- -kidneys can’t keep up with the excess fluid
- -condition examples: poorly controlled IV therapy, excessive irrigation of wounds or body cavities, excessive ingestion of water
- -conditions that can result in less fluid excretion: renal failure,heart failure, inappropriate antidiuretic hormone
signs and symptoms of fluid excess
- -BP elevated
- -pulse is bounding
- -respirations are increased and shallow
- -distended veins
- -edema in feet and legs
- -skin is pale and cool
- -increase urine output, clear urinte
- -weight gain
- -moist crackles in lungs
- -dyspnea
- -ascites
complications of fluid excess
- -CHF
- -pulmonary edema
- -organ failure=death
define pulmonary edema
fluid backs up into the lungs
diagnositic test results for fluid excess
BUN and hematocrit decreases
O2 is given for fluid excess, why?
- -ensure adequate perfusion of major organs
- -minimize dyspnea
- -careful not to go over 2L for pts with emphysema or chronic bronchitis, pt may lose the stimulus to breathe and may suffer from respiratory arrest
food sources of potassium
sweet potato beet greens potato yogurt prune juice soybeans banana spinach tomato juice, sauce milk, nonfat port chop apricots cantaloupe kidney beans OJ split beans
difference between cation and anions
cations=positive charge
anion=negative charge
normal sodium serum levels
135-145 mEq/L
sodium is important for:
- -maintaining serum osmolarity
- -important for cell function, especially in CNS
difference between hyponatremia and hypernatremia
hyponatremia=sodium deficit
hypernatremia=sodium excess
signs and symptoms of sodium hyponatremia
- -hyponatremia and fluid deficits has s/s of dehydration
- -hyponatremia with fluid excess has sings associated with fluid excess
more severe sodium deficit pt experiences:
mental status change disorientation confusion personality changes weakness nausea vomiting diarrhea