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ICF
ECF
Two main fluid compartments of the body:
Intravascular fluid
Fluid inside blood vessels:
Interstitial fluid (IS)
Fluid that bathes and coates outside of cells
Intracellular fluid
Fluid that is actually inside cells
Potassium (K+)
Most abundant ion in intracellular fluid (inside cells)
Sodium (N+)
Most abundant extracellular ion:
Isotonic state
water will move between compartments to restore sodium to what state?
More sodium concentration inside of the cells, water moves along osmotic gradient to balance. Cell expands/swells
What happens to cells in hypotonic environment?
There is more sodium outside of cells than inside, water moves out of cells along osmotic gradient to balance. Cells shrink/shrivel
What happens to cells in a hypertonic environment?
osmotic pressure
pulls fluid into vessels
Hydrostatic pressure
Pushes fluid out of vessels
Net filtation
Osmotic and hydrostatic pressure working against each other
Plasma proteins exert osmotic pressure against the hydrostatic pressure to pull flid out of the interstitial space and keep fluid inside vessels
How does albumin keep fluid in vessels?
Renin-angiotensin-aldosterone mechanism
Atrial natriuretic peptide (ANP)
Sodium related mechanisms for fluid/electrolyte balance [2]
sodium related mechanisms
fluid shifts
thirst
kidney/renal (ADH)
Mechanisms for fluid/electrolyte balance: [4]
of the blood
What does the suffix -emia mean?
Hypovolemia
Not enough water in the IV space
decreased fluid intake
Increased renal clearance of water (due to impaired renal function/inability to concentrate urine)
Hemorrhage
excessive diaphoresis
Causes of hypovolemia: [4]
decreased blood pressure
Increased HR, SOB, pale and cool (HPA axis response)
Initial signs and symptoms of hypovolemia: [2]
BP= HRx volume and force of contraction X peripheral vascular resistance
fomula for blood pressure:
Fluid shift
COMPENSATION for hypovolemia:
ADH
Renin-angiotensin-aldosterone
Correction mechanisms for hypovolemia: [2]
water shifts from interstitial or intracellular spaces into the IV space
Where does fluid shift to compensate for hypovolemia
dry skin
poor turgor
dry mucous membranes
confusion (brain cells are dehydrated)
SIgns and symptoms of intracellular dehydration
increased osmolarity of blood
decreased circulating blood volume decreases BP
dryness of mucous membranes of the mouth
How is thirst mechanism triggered? [3]
Osmoreceptors in the hypothalamus are triggered
stimulates the posterior pituitary to release ADH
ADH adds pores to renal tubular cells
Water reabsorption is increased
Decreased amount of concentrated urine (oliguria)
How does ADH correct hypovolemia? [5]
Decreased sodium concentration stimulates renin
Acts on juxtaglomerular cells in the kidneys
stimulates formation of angiotensin I
Angiotensin I converted to angiotensin II by converting enzyme
Stimulates secretion of aldoterone AND PVR to increase BP
Increased sodium reabsorption (water follows sodium)
Oliguria
How does RAA correct hypovolemia?
Aldosterone
Mineral corticosteroid that is synthesized and secreted from the adrenal cortex. Increases reabsorption of sodium and secretion of potassium by distal tubule of kidney
Hypervolemia
Too much water in intravascular space
decreased kidney function
Kidney disease
excessive administration of IV solution
hypernatremia
cortisone administration
Hypersecretion of aldosterone (Cushing’s)
Causes of hypervolemia:
Jugular veinous distention
Hypertension
Bounding pulse (increased cardiac output, arteries are “full”)
Weight gain
Decreased hemoglobin and hematocrit
Clinical manifestation of hypervolemia: [5]
Heart is not squeezing blood out into the ventricles, can back up into pulmonary circuit or periphery
How can heart failure cause hypervolemia?
Fluid shift
Compensation mechanism for hypervolemia:
Fluid shift from intravascular to interstitial space
Fluid shift for hypervolemia:
Peripheral edema or pulmonary edema (fluid being pushed into lungs)
Signs and symptoms of fluid shift for hypervolemia: [2]
ANP released
to increase GFR and inhibit RAA
Decreased sodium reabsorption
increased sodium excretion by kidneys (risk for hyponatremia)
Correction mechanism for hypervolemia:
Polyuria
Dilute urine
K+ reabsorption (risk for hyperkalemia)
Signs and symptoms of correction for hypervolemia (increased urine output due to ANP) [3]
135-145 mEq/L
Normal sodium values:
increased sodium loss (N/V, burns, etc.)
decreased sodium intake (rare)
decreased aldosterone
dilution of sodium
Causes of hyponatremia
Sweating stimulates thirst, there is an increased water intake that dilutes sodium. Need for electrolytes
How can water dilute sodium after exercising?
Hypochloremia: (<97mEq/L)
Hyponatremia is associated with which other electrolyte imbalance?
increased intake
hypertonic solutions containing sodium
Hperaldosteroneism (Cushing’s)
Renal failure
Increased water loss
Diabetes insipidus
Causes of hypernatremia:
Fluid shift
Compensation mechanisms for sodium imbalance
RAA/Aldosterone
ANP
Correction mechanisms for sodium imbalance: [2]
Fluid shift from intravascular (IV) to interstitial (IS). We want less volume
Compensation for hyponatremia
edema
Intravascular hypovolemia
Result of fluid shift from hyponatremia:
edema (extra fluid in interstitial space, can leave to increased ICP and cerebral edema)
IV hypovolemia (decreased BP and increased HR(HPA))
Behavioural/neurological changes (less sodium to depolarize, cell swelling)
Hyponatremia signs and symptoms
ANP
Thirst
Mechanisms for correcting hypernatremia [2]
Fluid shift from intracellular to IV
Compensation for hypernatremia:
Intracellular dehydration
hypervolemia
Fluid shift for hypernatremia results in what? [2]
thirst
dry mucous memranes
Restlessness/ confusion (water loss from brain cells)
Agitation, seizures, coma, muscle spasms
Intracellular dehydration from hypernatremia S+S: [4]
Increases GFR, and inhibits RAA.
Results in decreased sodium reabsorption.
How does ANP correct hypernatremia?
3.5-5.0 mEq/L
Normal values for potassium in IV space:
decreased intake due to elderly, alcoholism, eating disorders associated with purging
loss of potassium
Causes of hypokalemia:
renal disorders
GI disorders
continuous NG suctioning
Diabetic ketoacidosis
Laxative abuse
hyperaldosteronism
Diuretic use
Things that can cause a loss of potassium: [7]
HAHA TRICK QUESTION no signs or symptoms for mild LOSSES💜
Mild loss of potassium signs and symptoms
skeletal muscle weakness
depressed ventillation
smooth muscle weakness
decreased nutrient absorption
cardiac muscle weakness
cardiac arrythmias can lead to cardiac arrest
Severe potassium loss signs and symptoms:
increased intake
Shift of potassium from cells to ECF
decreased renal excretion
K+ sparing diuretics
diabetic ketoacidosis
Causes of hyperkalemia:
cell trauma (burns)
insulin deficiency
hypoxia
causes for K+ shift from cells to ECF: [3]
HAHA TRICK QUESTION no signs or symptoms for mild LOSSES💜
signs and symptoms for mild excess of potassium
skeletal muscle weakness
neuromuscular irritability
cardac muscle weakness
cardiac arythmias
severe hyperkalemia signs and symptoms:
Tetany
Hypomagnesemia can lead to what?
Calcium
Magnesium aids in absorption and metabolism of what?
CNS issues
respiratory paralysis
coma
heart block
cardiac arrest
Hypermagnesemia can lead to what?
CHO metabolism
protein synthesis
nucleic acid synthesis
musclular contraction
Magnesium is important for what? [4]
0.74-1.07 mmol/L
Normal magnesium levels
muscular contraction
cardiac function
transmission of nerve impulses
blood clotting
Calcium is important for what? [4]
1/16-1/32 mmol/L
Normal ionized calcium levels
tetany
convulsions
Hypocalcemia can lead to what? [2]
cardiac issues
coma
Hypercalcemia can lead to what? [2]
physical signs
checking serum electrolyte levels
Consider IV fluids/NPO status
do I&O
What to look for when assessing fluid/electrolyte imbalances: [4]
600-800 to account for insensible losses
How much to add to output when calculating I&O?
Sodium
where do you want the water to go?
Choice of IV solution depends largely on what? [2]
0.45% NaCl, 0.33% NaCl, D5W
Hypotonic crystalloid IV solution:
D5W with R/L
D5W with 0.45%NaCl
D5W with 0.9% NaCl
Hypertonic crystalloid IV solution: [3]
0.9%NaCl, R/L, 2/3 & 1/3
Isotonic crystalloid isotnic solution
Hypertonic
What type of solution to give hypovolemic patient?
Hypotonic
Iv solution to give patient with intracellular dehydration
Combinations of dextrose and saline (2/3 and 1/3. Glucose for energy, free water, electrolytes)
What to give in maintenance IV:
0.9% NaCl : Isotonic
If extremely hyponatremic, hypertonic slowly in small amounts
IV fluid to give hyponatremia
Hypotonic D5W. (dexrose gets metabolized to CO2 and H20, dlutes the sodium)
IV solution to give hypernatremia:
Diuretics
drugs to give hypervolemia:
Will need both hyper and hypotronic but correct vascular problems FIRST!
what happens if a patient has severe hypovolema AND intracellular dehydration?
Increased sodium means some sodium will be exchanged for potassium and potassium will be lost.
Why are patients receiving 0.9% NaCl at risk for hypokalemia?