Nur 339 Exam 3 patho

intracellular fluid (ICF)

majority of the fluids

extracellular fluids ECF

interstitial- around cells, intravascular/plasma- circulating fluids, transcellular- other fluids- spinal, digestive

total body water

60% body weight, ICF 40%, ECF 20%

fluid and solute movement basic principles

separated by semipermeable membranes, some allowed to pass freely, larger compounds restricted

pressure gradient

between 2 sides of membrane causes the fluids and particles to move

high to low concentration

diffusion- movement of particles, osmosis- movement of water- passive, does not require energy

low to high concentration

active transport, requires energy for movement to occur

osmolarity

number of milliosmoles of solute per 1 kg of water 280-295

tonicity

ability of solutes to cause an osmotic gradient that promotes water movement- salt concentration

tonicity determined by

how it compares to normal blood concentration

tonicity types

isotonic- equal to blood, hypertonic- concentrated blood hypotonic- dilute blood concentration

isotonic

concentration btwn solute and water balanced, no net movement btwn ICF and ECF, no change in cells

hypotonic

ECF less concentrated, dilute vascular space with concentration of solutes in the cells, net movement from ECF> ICF, cell size increases due to fluid incerease

hypertonic solution

ECF more concentrated, pulls fluid from cells to blood, ICF> ECF, cell size shrinks

capillary hydrostatic pressure

pressure exerted by fluids against bld vessel walls- reflects BP, pressure is higher at arterial end, lower at venous

filtration

movement of fluid from hi pressure to low, hi arterial pressure pushes fluids out of capillary to ICF, fluids reabsorbed in lower pressure venous system with osmotic pressure

hydrostatic pressure pushes

fluids out to ICF

osmotic pressure pulls

fluids into ECF

colloid oncotic pressure

osmotic pressure from albumin, contributes to osmotic pressure in venous end

fluid intake

primary thru diet

fluid loss

through kidneys, lungs, skin, GI

conditions that affect TBW (total body water)

V D, dehydration, renal function, HF, burns, meds

evaluating fluid status

I&O, serum osmolarity, urine specific gravity, Hgb/Hct

serum osmolarity- most reliable for fluid status

reflect serum Na, 275-290, can estimate by doubling Na level

urine specific gravity- less reliable

measures density of urine compared to water, normal 1.005-1.030

Hgb/Hct

decreased w fluid volume excess- dilute ECF, increased w fluid volume deficit- concentrated ECF

BUN fluid status-not reliable for kidney function

measures urea in blood, 10-20, increased by poor renal function, dehydration

creatinine- more reliable than bun

0.7-1.4- less affected by hydration and protein intake, increased w renal dysfunction

urine sodium

changes w sodium intake, increase intake=increase urine sodium, used to assess volume and kidney function

kidneys

regulates ECF volume and concentration by ^ or decreasing UO, involved w regulation of electrolytes and acid base

heart and bld vessels

decreased CO leads to decreased renal perfusion and function

lungs

loss of water thru lungs, also regulate acid base thru regulation of CO2

pituitary

ADH released when need to conserve water, dehydration, bld loss, acts in kidneys

adrenal

aldosterone causes Na and water retention, K loss. decreased aldosterone does opposite effect

baroreceptors

respond to changes in circulating volume, decreased stimulus to receptors stimulates SNS> increase HR BP

ARA system

key fluid regulator, in response to decreased renal perfusion or decreased BP

ADH in response to increased blood concentration

increased intake or decreased volume- secreted by pituitary

ADH increased water reabsorption into blood stream

increases vascular volume and decreased UO

thirst- first mechanism

stimulated by increase concentration of bld or decrease volume, from hypothalamus

ARA system pathway

liver produces angiotensinogen in plasma, renin converts it to angiotensin I, ACE converts I to II, II causes increased BP and stimulates release of aldosterone, aldosterone causes Na and water retention, increases BP and fld volume

hypovolemia

loss of ECF exceeds intake., loss of fluid and electrolytes in equal proportion

hypovolemia causes

Increase loss or decreased intake, shift of fluids from vascular space to body space(edema, burn)

hypovolemia Dx

BUN and Hgb/Hct increased, Na and K abnormalities, decreased UO

hypovolemia CM

wt loss, dry MM, BP may increased then drop, increased HR and temp, dizzy weak confused, OH, decrease UO

hypovolemia treatment

replace fluids- start with iso then switch to hypo once BP stabilizes, fluid challenge- 100-200ICF over time to challenge renal system- should see increase UO

hypervolemia

expansion of ECF caused by retention of water and sodium in same proportions- isotonic, increased body sodium

hypervolemia Dx

bun and H&H low, pulmonary congestion, Na level normal, Urine sodium hi

hypervolemia CM

dependent edema, listened neck veins, wt gain, increased BP and HR, lung crackles

hypervolemia treatment

reduce fluid retention, I&O, daily weight, low Na diet

edema

swelling produced by expansion of interstitial fluid volume

edema causes

increased cap hydrostatic pressure, decrease cap oncotic pressure, increased capillary permeability, obstruction of lymph flow

third spacing

accumulation of fluid in a body cavity or body tissue

third spacing causes

increase fld volume, increase cap pressure, low Na level, decreased colloid osmotic pressure, lymph system obstruction

third spacing loss phase

loss of fld and proteins from vascular to interstitial space, 24-72hrs, treatment- fluids and prevent shock

third spacing reabsorption phase

healing begins and fluid shifts back to vascular space, S&S of hypovolemia resolve, prevent fluid overload

crystalloids

IV solution that contain electrolytes and other ECF substances, replace fluid and promote renal function, Na most common

isotonic fluids

expand circulating volume, 0.9% NS< LR, D5W, D5.9

hypertonic fluids

expand plasma by drawing water from cells and ICF, decrease cell edema- mannitol, 3% NS

hypotonic fluids

move out of ECF to ICF, hypernatremia and cell dehydration, 0.45% NS, D5W

electrolytes

substances that have positive or negative charge when dissolved in water

electrolytes function

body regulate chemical reactions in body, regulate muscle contractions, maintain fluid balance

extracellular electrolytes- larger amts

Na, Cl, Ca

intracellular electrolyes- smaller amts

K, Mg, phosphorus

Na value

135-145

Chloride value

97-107

Calcium value

9-10.5

Potassium level

3.5-5

Mg level

1.3-2.1

Phosphorus level

3-4.5

Na most abundant electrolyte in

ECF

sodium Na function

primary determinant of fluid volume balance, Na gain or loss accompanied by water gain or loss, binds with Cl to form salt

Na contributes to

muscle contraction and nerve impulse transmission, sodium- potassium pum

Na regulated by

ADH, thirst, RAA system

hyponatremia

Na <136

Acute hyponatremia

commonly seen in post pt from IV fluids- Na level low due to increase fluid in vascular space- dilution

chronic hyponatremia

seen in pt outside of hospital, longer duration and less serious neurological manifestations

exercise related hyponatremia

loss of Na in sweat or increase fluid intake before exercise- most common in women

hyponatremia causes

usually water issue than sodium, dilutional- excess fluid, aldosterone deficiency- decreases Na and water retention

urine sodium helps determine if

renal or non renal cause

renal cause hyponatremia

urine sodium high, salt loss with kidney malfunction or diuretic use

non renal cause hyponatremia

urine sodium low, kidneys retain sodium to compensate for water loss, V D

hyponatremia CM

SALTLOSS- stupor, anorexia, lethargy, tendon reflexes decreases, weakness, OH, seizures/HA, stomach cramping

severe hyponatremia

<115, Increase ICP- lethargy, muscle twitching, weakness, seizures, death

hyponatremia treatment

increase Na intake, isotonic fluids, severe- hypertonic

hypernatremia

too much Na or too little water, >145

hypernatremia causes

decreased fld intake, hypertonic enteral feedings without water, diarrhea, loss thru lungs or skin, diabetes

hypernatremia CM

THIRST, fever, restlessness, fluid retention, NV< lethargy, anorexia, dry mouth

hypernatremia treatment

hypotonic IV fluids or D5W

potassium K

primary intracellular electrolytes, minor variations significant

K function

NM activity, cardiac function, loose in urine stool and sweat, kidneys control amt of urine loss

hypokalemia

<3.5

hypokalemia causes

K losing diuretics, meds, GI losses, acid base imbalance, insulin, poor nutrition, MG depletion

hypokalemia CM

weak, hypoactive reflexes, decrease GI motility, leg cramps, NV, abd distention, cardiac- ventricular arrhythmia, ECG changes

hypokalemia treatment

increase K in diet, oral replacement, IV infusion NOT PUSH

hyperkalemia

>5

hyperkalemia causes

renal failure w decreased K excretion, excess intake, meds, tissue trauma, false hi

hyperkalemia CM

cardiac if >7- ECG changes and arrhythmias, muscle weakness cramps, distention, decreased urine K loss

hyperkalemia treatment

restrict K intake, cation exchange renin, IV calcium gluconate

Ca

majority stored in bones and teeth, 3 forms

Ca forms

ionized- 50%- active state, bound to protein albumin- inactive if bound, combines w non proteins- phosphate, citrate, carbonate