adult chapter 13: fluid and electrolyte balance

what is a solvent?

substance that is able to dissolve other substances

what is a solute?

minor component in a solution that is dissolved in the solvent

what are two examples of solutes?

electrolytes and ions

how much of the body is intracellular fluid?

2/3

how much of the body is extracellular fluid?

1/3

what is the body's extracellular fluid divided into?

interstitial fluid and plasma

how is total body water divided?

extracellular fluid and intracellular fluid

what does total body weight depend on?

age, gender, and percentage body fat

what is filtration?

mass movement of water and solutes from plasma to the renal tubule

what is diffusion?

movement of particles from an area of high concentration to an area of low concentration

what is a clinical example of diffusion?

transport of most electrolytes and other particles through the cell membrane

what is osmosis?

movement of water through a semipermeable membrane to achieve an equilibrium of osmolarity

what is osmolarity?

number of milliosmoles in a liter of solution

what is osmolality?

number of milliosmoles in a kilogram of solution

what is an isotonic solution?

contains equal concentrations of solutes/water concentration on both sides

how are cells affected by an isotonic solution?

cells retain their normal size and shape

what is a hypertonic solution?

when there is more water and less salt inside the cell, it will flow out of the cell shrink by diffusion

how are cells affected by a hypertonic solution?

cells shrink

what is a hypotonic solution?

when there is more water and less salt outside the cell, it will flow into the cell by diffusion causing it to swell

how are cells affected by a hypotonic solution?

cells become bloated and burst (lyse)

what is isotonic (normotonic) fluid also known as?

isoosmotic

what is hypertonic fluid also known as?

hyperosmotic

what is hypotonic fluid also known as?

hypo-osmotic

what is fluid balance closely linked to/affected by?

electrolyte concentrations

what factors affect the amount and distribution of body fluids?

age, gender, and fat

what is fluid intake regulated through?

thirst drive

true or false-fluid loss occurs through several routes, such as the kidneys, skin, lungs, and intestinal tract

true

what is aldosterone?

"salt-retaining hormone" which promotes the retention of Na+ by the kidneys. na+ retention promotes water retention, which promotes a higher blood volume and pressure

what is antidiuretic hormone?

hormone secreted by the posterior pituitary gland to prevent the kidneys from expelling too much water

what are the two natriuretic peptides?

atrial natriuretic peptide (ANP)

brain natriuretic peptide (BNP)

does the renin angiotensin aldosterone system work to increase or decrease blood pressure?

increase blood pressure

what is released by the kidneys in response to low blood pressure?

renin

what is the normal sodium range?

136-145 mmol/L

what is the normal potassium range?

3.5-5 mEq/L

what ist he normal calcium range?

8.5mg/dl-10.5mg/dl

what is the normal magnesium range?

1.7-2.2 mg/dL

how does sodium often enter the body?

through foods and fluids such as smoked or picked foods, snack foods, and condiments

what electrolyte is the major cation of intracellular fluid?

potassium

what foods are highest in potassium?

meat, fish, many vegetables and fruits

what electrolyte helps to reduce blood pressure?

potassium

what electrolyte is commonly found in a variety of unrefined foods?

potassium

what electrolyte in excessive amounts can lead to health problems like high blood pressure?

sodium

what electrolyte is often present in high amounts in food products?

sodium

what electrolyte forms and keeps strong bones and teeth?

calcium

what does the absorption of calcium require?

active form of vitamin D

where is calcium stored?

in the bone

what is released when when more calcium is needed?

parathyroid hormone (PTH)

when excess calcium is present, what does the thyroid gland secrete?

thyrocalcitonin (TCT)

where is magnesium mostly stored?

bones and cartilage

what electrolyte assists with skeletal muscle contraction, carbohydrate metabolism, generation of energy stores, vitamin activation, blood coagulation, and cell growth?

magnesium

what is the pathophysiology of dehydration?

when fluid intake/retention does not meet the body's fluid needs, fluid volume deficit results (especially plasma volume)

what test assesses for dehydration?

skin turgor

true or false-mild dehydration is common among healthy adults, and is easily corrected or prevented by matching fluid intake with fluid output

true

what types of beverages can increase fluid loss?

beverages with caffeine

what are the 6 signs of temporary dehydration?

hot red skin (no sweat)

confusion

thirst

dry chapped lips

salty white residue around lips

fatigue

what are the 6 signs of chronic dehydration?

constipation

high blood pressure

dry skin

fatigue

achy joints

headaches

studies say what type of water hydration is 17% better than plain water?

alkaline water

in dehydration labs, is hematocrit elevated or depressed?

elevated

in dehydration labs, is serum osmolality elevated or depressed?

elevated (>295 mOsm/kg)

in dehydration labs, is serum sodium elevated or depressed?

elevated (>145 mEq/L)

in dehydration labs, is urine specific gravity elevated or depressed?

elevated (>1.030)

true or false-a single test is definitive for dehydration

false

what imaging assessment aids in the diagnosis of dehydration?

ultrasonography with basic echocardiography

why does poor perfusion occur when a patient is dehydrated?

due to excess fluid loss or inadequate fluid intake

when a patient is dehydrated, why are they at a higher risk for potential injury?

due to blood pressure changes and muscle weakness

how is dehydration treated?

restoring fluid balance through fluid replacement and drug therapy while preventing injury

what is the most important strategy to prevent recurrence of dehydration?

education

what is the best piece of advice when teaching a patient how to prevent dehydration?

drink small amounts of fluids as often as you can tolerate them, watch the clock and plan to drink at least a cup of fluid every 1 to 2 hours

how much water should a patient drink a day?

8 to 12 cups

true or false-in addition to plain water, patients should also drink fruit juices, soft drinks, flavored waters, decaffeinated coffee and tea, sports drinks, milk, and other beverages

true

what foods are high in fluids?

bouillon, broth-based soups, gelatin, fruit ices, popsicles, sherbet, milkshakes, and medical nutritional supplement drinks

patients should limit drinks with caffeine to how many a day?

only two a day

patients should maintain a daily fluid intake of at least how many mL?

1500 mL

what is fluid overload also referred to as?

hypervolemia

what complications can severe fluid overload cause?

heart failure and pulmonary edema

what electrolyte imbalances can fluid overload lead to?

dilution of sodium and potassium

what severe consequences can result from sodium and potassium dilution?

seizures, coma, death

what cellular activity is observed in hyponatremia?

excitable cellular activity

what system changes occur with hyponatremia?

cerebral, neuromuscular, intestinal, and cardiovascular changes

what position should a patient with fluid overload be in?

semi-fowler's

true or false-when in fluid overload, the patient should be kept warm to promote peripheral circulation

true

what is the first step in treating hyponatremia?

determine the cause

what therapies are used to treat hyponatremia?

drug therapy and nutrition therapy

what is the primary goal of managing fluid overload?

restoring normal fluid balance while preventing complications

what is euvolemic hyponatremia?

the water in the body increases but the sodium stays the same

what is hypervolemic hyponatremia?

sodium and water content in the body increases, with water retention being greater

what is hypovolemic hyponatremia?

water and sodium are both lost, but unequally, with the sodium loss being greater

what is pseudo hyponatremia?

falsely low serum sodium measurement (ex: bad blood draw technique)

what is translocational hyponatremia?

aka pseudohyponatremia that is

caused by excess of other solutes in the blood (glucose, mannitol, glycine, maltose, proteins, lipids)

what cerebral symptoms are associated with hypernatremia?

altered cerebral function

what muscular and cardiac issues may occur with hypernatremia?

muscle twitching and decreased cardiac contractility

how frequently should serum sodium be measured during fluid resuscitation for hypernatremia?

every 4 hours initially, then every 12 hours once stable

what therapies are used to treat hypernatreamia?

drug therapy and nutrition therapy

true or false-hypernatremia should be managed as a medical emergency

true

in the acronym "FRIED SALT," which represents the signs and symptoms of hypernatremia, what does the letter "F" stand for?

flushed skin and fever (low-grade)

in the acronym "FRIED SALT," which represents the signs and symptoms of hypernatremia, what does the letter "R" stand for?

restless, irritable, anxious, confused

in the acronym "FRIED SALT," which represents the signs and symptoms of hypernatremia, what does the letter "I" stand for?

increased blood pressure and fluid retention

in the acronym "FRIED SALT," which represents the signs and symptoms of hypernatremia, what does the letter "E" stand for?

edema peripheral and pitting

in the acronym "FRIED SALT," which represents the signs and symptoms of hypernatremia, what does the letter "D" stand for?

decreased urine output and dry mouth

in the acronym "FRIED SALT," which represents the signs and symptoms of hypernatremia, what does the letter "S" stand for?

skin flushed