Fluid and Electrolytes Flashcards
Two main fluid components of body
Extracellular— subgroups are plasma and interstitial fluids (fluid that bathes cells)
And Intracellular
How much does one liter of water weigh?
1 kg
is there more intracellular or extracellular fluid?
ICF 66%
What is main cation and anion of ECF?
Sodium + and chloride-
What are main cation and anion of ICF?
Potassium + and phosphate -
Define diffusion.
Movement of molecules from high to low until balanced.
Define active transport.
Movement of molecules from area of low to high…being pushed uphill…takes energy. Example is sodium potassium pump. Atp is the fuel
Define osmosis.
Movement of water from area of low solute to high solute. Water tries to “water down” substance. Water follows salt. Water attempts to balance
What is normal plasma osmolality value and what is its significance?
280-295 mOsm/kg milliosmoles/kg
This is an important indicator of water balance in body. Too high and it means water deficit…too low and it means water excess. This is because this is measurement of molecules to water.
What happens to a cell if bathed in a hypotonic solution? (ECF)
Water moves into cell…water is following the saltier of the two spaces
What happens to cell if bathed in ECF that is hypertonic?
Water leaves cell..shrinks…water is following the saltier of the two spaces.
What is hydrostatic pressure?
The pressure water exerts on membrane. Think pressure water exerts on inside of a water hose wall.
What is oncotic pressure, also called colloidal osmotic pressure?
Pressure the plasma colloids (proteins) exert in a solution. This draws water into vessels to water down the proteins.
What is fluid spacing?
The distribution of body water
What is first spacing?
Normal balance between ICF and ECF
What is second spacing?
Abnormal accumulation of interstitial fluid (fluid that bathes the cells) seen as edema
What is third spacing?
Excessive fluid collecting in areas that it becomes trapped…ascites, edema from burns, trauma or sepsis
What role does the hypothalamus and pituitary play in water balance?
Osmorecetors in the hypothalamus are activated by an increase in plasma osmolarity or water deficit. This is the chain that follows:
Increase salt or decrease body water….
Hypothalamus alarms….
Thirst kicks in…
Pituitary sends out ADH (vasopressin) to kidneys….
Kidneys hang onto water
This combo of increased thirst and conservation of water restores balance
What does the RAAS do?
Manages drops in BP by activating Angiotensin 2 and aldosterone to increase BP
How does Angiotensin 2 increase BP?
Vasoconstriction and increases blood volume
How does Aldosterone increase BP?
Retains Na and excretes potassium
What are the natural antagonists hormones to the RAAS system?
Natriuretic peptides made by the heart…
Atrial natriuretic hormone ANH
and B type natriuretic peptide BNP. These work to lower BP
What is normal range for serum sodium?
135-145 mEq/L
What is the major body system affected by sodium imbalances?
Neurological.
Looks like changes in mental status
Agitation, restlessness, lethargy, confusion, tremors, seizures
What is relationship of sodium and potassium?
Inverse. They balance each other. Any factor that increases sodium decreases potassium and vice versa
When rebalancing sodium in body what is the caution?
Must do it slowly with careful monitoring or could cause dangerous fluid shifts into cells.
What are some common causes of hypernatremia?
Impaired thirst cues, water loss without salt loss, too much salt ingestion or hypertonic IV solution (3% NS), Cushings syndrome (affects cortisol in body by increasing cortisol and remember too much steriod=too much sodium),
Hypernatremia s/sx.
Think big and bloated.
Late signs:
SWOLLEN DRY TONGUE
N/V
INCREASED MUSCLE TONE
Confusion
Red skin
Edema
Low grade fever
Diarrhea
Remember: Sodium affects the neuro system profoundly
What is SIADH?
Syndrome of inappropriate ADH
In this syndrome ADH is elevated—meaning water is retained and dilutes sodium. This leads to a certain type of hyponatremia called Euvolemic hyponatremia. Too much water-too little sodium.
Signs and Symptoms of hyponatremia.
Think neurological s/sx.
Depressed and deflated—–
Lethargy, confusion, agitation, restlessness, SEIZURES AND COMA, TACHYCARDIA, WEAK THREADY PULSE, RESPIRATORY ARREST, diminished reflexes, muscle spasms, abdominal cramping
Interventions for SIADH.
Fluid restrictions, Declomycin-remember no dairy or antacids with.
What are normal potassium serum levels?
3.5—-5.0 mEq/L
Anything over 7 is extremely dangerous
What are two main body systems affected by potassium imbalances?
Neurological and muscular
Causes of hyperkalemia.
Burns or any major tissue damage (destroys cells and they release K+)
Acidosis
Adrenal insufficiency (Addisons disease)
RENAL FAILURE—most common
Potassium sparing diuretics (aldactone, triamterene)
NSAIDS, ACE inhibitors
Signs and symptoms of hyperkalemia.
Think neuro/muscle..overstimulated.
Everything tight and contracted!
GI muscle will be jumpy–think cramping, diarrhea, vomiting
Confusion, irritability, fatigue, muscle weakness, increased DTRs, decreased muscle tone.
Dsyrhythmias—Tall peaked T wave, widened QRS, Loss of p wave, Bradycardia, hypotension
Nursing interventions for hyperkalemia.
Monitor cardiac, respiratory, and neurological.
Restrict potassium intake
Dialysis
Kayexalate (slow acting)
Lasix (potassium wasting diuretic)
Thiazides (potassium wasting diuretics)
Hypertonic solution of insulin and glucose (moves K+ back into cell.)
Dextrose 20% and insulin (fast acting)
Causes of hypokalemia.
Think abnormal loss from kidneys/GI tract.
Diuretics that waste potassium. (Lasix)
Corticosteroids
Cushings syndrome. (too much aldosterone)
Fluid loss (diarrhea, NG suction, vomiting)
Alkalosis