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119 Cards in this Set

  • Front
  • Back
What is ICF?
intracellular fluid, the volume of fluid inside all cells
What is ECF?
extracellular fluid; the volume of fluid outside cells: intravascular volume (plasma) and interstitial (space between capillaries and cells)
What percentage of the total body weight is fluid in the ICF?
40%
What percentage of the total body weight is fluid in the ECF?
20% (16 in interstitial, 4 in plasma)
What is the pressure needed to prevent water from passing through a semi-permeable membrane?
oncotic pressure
What term describes when a solution has equal amounts of water on both sides of a membrane with the same total concentration of solute particles?
isotonic
What maintains intravascular osmotic pressure?
Sodium
What maintains intracellular osmotic pressure?
Potassium
What is the equation for calculating osmolality?
2(plasma Na) + (glucose/18) + (BUN/2.8)
What is normal blood osmolality?
276-295 mOsm/kg
What are the two conditions that effect fluid balance?
Change in blood osmolality and change in blood volume
What controls changes in blood osmolality or volume?
hormones
What are the steps to normalizing osmolality in a fluid volume decrease?
1.When fluid volume decreases in the intravascular compartment, Na concentration (osmolality) increases.
2.Increased Na concentration causes Pituitary to release anti-diuretic hormone (ADH)
3.ADH stimulates kidney to re-absorb more water into intravascular compartment.
4.Blood volume and serum Na return to normal
5.Decreased osmolalityturns off ADH, kidneys excrete more water in urine.
What happens when blood volume decreases to reach normalization?
1. Decreasedblood volume:
a.Turns on Renin-Angiotensin-Aldosteronesystem (RAAS)
b.Angiotensinis a vasoconstrictor –increases blood pressure
c.Aldosteroneincreases kidney re-absorption of Na and water to increase blood volume.
What happens when blood volume increases to reach normalization?
2. Increasedblood volume:
Stimulates atrialnatriuretichormone which causes kidney to excrete more Na and water to decrease blood volume
What system does decreased blood volume turn on?
Renin-Angiotensin-Aldosterone system (RAAS)
What is angiotensin?
vasoconstrictor - increases blood pressure
What does aldosterone do?
increases kidney reabsorption of Na and water to increase blood volume
What does increased blood volume stimulate the production of?
atrial natriuretic hormone
What does atrial natriuretic hormone do?
causes kidney to excrete more Na and water to decrease blood volume
What are the sources of fluid intake?
IV fluids, medications given via IV drip, water flushes given with crushed medications, water flushes to keep tubes patent (?), water contained in tube feedings or TPN, oral intake
What are the sources of fluid output?
urine/stool, nasogastric tube suction, chest tubes, percutaneous drains, wound drainage, ostomies, fistulas, insensible losses, accelerated insensible losses (burns, tracheostomies, fever)
What are some common conditions that increase body volume?
heart failure, renal failure, liver failure (due to decreased albumin), sepsis (due to capillary leak), excessive sodium intake
What are some conditions that decrease body volume?
diarrhea, vomiting, increased sweating, diuretic drugs
What is the definition of hypernatremia?
plasma Na above 145 mEq
What is the definition of hyponatremia?
plasma Na below 135 mEq
What is the definition of hyperkalemia?
plasma K above 5 mEq
What is the definition of hypokalemia?
plasma K below 3.5 mEq
What values are included in a BMP?
Na, K, Cl, CO2, Ca, BUN, Cr
Are phosphorus and Magnesium included in a BMP?
no, must be ordered separately
What does a BUN to Cr ratio of > 20 suggest?
dehydration
What is the risk if total protein and albumin is low?
risk for 3rd spacing of fluid is increased
What are the normal lab values for Sodium?
135-147 mEq/L
What are the normal lab values for Potassium?
3.5-5mEq/L
What are the normal lab values for Chloride?
95-107 mEq/L
What are the normal lab values for Bicarb?
22-26 mEq/L
What are the normal lab values for Glucose?
60-110mg/dL
What are the normal lab values for BUN?
7-21 mg/dL
What are the normal lab values for Creatinine?
0.5-1.4mg/dL
What are the normal lab values for calcium?
8.8-10.3 mg/dL
What are the normal lab values for phosphorus?
2.5-4.5 mg/dl
What are the normal lab values for magnesium?
1.6-2.4 mEq/L
What are the treatment goals in choosing IV fluids?
1.Hemodynamic stability
2.Optimal oxygen delivery
3.Fluid balance without edema
4.Correct electrolytes22
What is the HR and BP in euvolemic?
normal
What IV fluid should be give in euvolemic condition?
D5 1/2NS with KCL 20mEq/L; needs isotonic maintenance fluid that will distribute equally to all compartments at a rate the keeps intake=output
What is the current weight in euvolemic?
normal
What is another term for dehydrated?
hypovolemic
What is the HR in hypovolemic?
increased HR
What is the BP in hypovolemic?
decreased BP
What fluid should be used in hypovolemic?
isotonic fluid until euvolemic (eg 0.9% sodium chloride)
What are the s/sx for hypovolemic/
thirsty, dry mucus membranes, altered mental status
What can cause volume depletion leading to hypovolemic condition?
gi bleed, trauma, excessive diarrhea
What is another name for fluid overloaded?
hypervolemic
What can cause hypervolemic condition?
CHF, Pulmonary Edema, Cirrhosis
What fluid should be given for hypervolemic condition?
None; need to remove water from interstitial space, limit sodium, minimal maintenance fluid, may need to use diuretic to get Output > Input
What are crystalloids?
electrolyte containing IV fluids; sodium content determines into which compartment the fluid distributes
What are colloids?
blood products, albumin, plasma proteins, dextran; contain high molecular weight molecules, stay in intravascular compartment
Which crystalloid has the same NA concentration and osmolality as plasma, has no movement of water across the cell membrane, and distributes to intravscular and interstitial space but not intracellular?
isotonic - 0.9% NaCl
Which crystalloid has less Na concentration and less osmolality than plasma, approximately 10% stays in the IV compartment and 90% distributes to interstitial and intracellular space, not good for resuscitationn but good for maintenance fluid?
Hypotonic - 0.45% NaCl, D5 1/2NS
Which crystalloid pulls water from interstitial and intracellular space into intravascular, primarily used for cerebral edema?
hypertonic - 3% NaCl, mannitol
What effect do colloids have on ECF/ICF fluid distribution?
draw water from the interstitial space to expand the intravascular compartment; the amt of water pulled from the interstitial space is greater than the volume infused
Where is the place in therapy for colloids?
anaphylaxis, shock, Acute Respiratory Distress Syndrome (ARDS), multi-organ failure
How much fluid should a pt receive per day?
30-35 ml/kg
What are the two categories of hyponatremia?
Hypertonic hyponatremia (10%) and hypotonic hyponatermia (90%)
What are the three types of hypotonic hyponatremia?
hypervolemic hyponatremia, euvolemic hyponatremia, hypovolemic hyponatremia
What is the condition in which Na and water are both increased but water more than Na so that Na appears low?
Hypervolemic hyponatremia
What are the medical conditions associated with Hypervolemic Hyponatremia?
CHF, cirrhosis, acute or chronic renal failure
If a pt is hypervolemic hyponatremia with a fluid restriction and npo what should be used for fluid?
0.9% NaCl at rate of 1000 to 1500ml/d
What is the condition in which pt has normal Na but increased total body water, so serum Na appears low?
euvolemic hyponatremia
What are the common causes of Euvolemic Hyponatremia?
SIADH, hypothyroidism, surgery, some drugs (NSAIDS)
What is the tx for Euvolemic Hyponatremia?
fluid restrict to 250-500ml/d using 0.9% NaCl and add diuretic
What is the condition in which the pt has decreased Na and decreased total body water but more Na than water has been lost?
hypovolemic hyponatremia
What are the common causes of hypovolemic hyponatremia?
vomiting, diarrhea, hyperglycemia, thiazide diuretics
What does pt require with hypovolemic hyponatremia?
volume expansion and Na replacement; use 0.9% NaCl calculated by formula; be sure to monitor urine output as ECF fluid replacement may inhibit ADH resulting in significant diuresis that can increase serum Na too fast
What is the formula for estimating change in plasma sodium?
(IVna-Sna)/(BW+IVvol); IVna= Na conc of IV fluid, BW= body water, Sna=serum NA, IVvol= 1L; BW =0.6X weight for men and children < 70Kg, 0.5X weight for men >70kg and women <77kg, 0.45X weight for women ?70kg
What are the rules for correcting hyponatremia?
If serum Na > 120, correct at rate not > 12 meqin 24 hours until symptoms resolved; If serum Na < 120, correct more rapidly until 120 mEq; infusion rates of > 250 ml/h should be reserved for emergencies (pulmonary edema or CHF)
What can happen when correcting serum Na faster than 12 mEq/24h?
osmotic demyelination syndrome due to rapid shift of water from the brain
What condition is characterized by a serum Na of > 145 mEq/L and increased osmolality?
hypernatremia (rare)
What are the common causes of hypernatremia?
diabetes insipidus (lack of adh), fever with lack of water
What pts is hypernatremia most common in?
infants and elderly
What is the treatment for hypernatremia?
use 0.9% NaCl if BP is low, otherwise use 0.45% NaCl and correct 0.5 to 1 mEq/h
What serum Na results in a 75% mortality rate?
> 160 mEq/L
When does serum K increase?
with hyperglycemia and acidosis
When does serum K decrease?
with alkalosis and low magnesium
How much KCl shoud be given to raise serum K by 0.1mEq?
10 mEq KCl
Which route of administration is preferred in K replacement?
oral, given IV if patient is NPO, EKG changes, muscle weakness, Cardiac patient or on Digoxin
What is the max infusion rate of K if not on monitor?
10mEq/h
What is the max infusion rate of K if on monitor?
20 mEq/h
What is the minimum volume KCl must be diluted in?
50ml
What is a K run?
10mEq KCl in 50 ml D5W over 1 h
What should be monitored during K replacement?
magnesium, replace simultaneously if low
When should serum K be rechecked?
after 40mEq of K infusion
What is the role of magesium in electrolyte balance?
plays significant role in renal absorption of potassium
Where is most Mg stored?
bone
What are common causes of hypomagnesemia?
decreased absorption (malnutrition, alcohol, NG tube) and increased renal excretion (hypercalcemia, diuretics, Amphotericin B, aminoglycosides)
If a patient is asymptomatic, what should the replacement of magnesium be?
0.5 to 1 g/h
If pt is symptomatic/seizures and has Magnesium < 1, what should the replacement be?
2g in 6 ml NS over 1 min, then infusion of 0.5mEq/kg over 6 h
If Mg is <1.4 how should the replacement be?
2g over 4h x2
If Mg is 1.5 to 1.7 how should the replacement be?
2g over 4 h
If Mg is 1.8 to 2 how should the replacement be?
1g over 4 h
What is pre-eclampsia?
sever high B/P during pregnancy
What is eclampsia?
high B/P with seizures during pregnancy
What is the treatment for eclampsia?
magnesium 6g bolus then continuous infusion of 2g/h to prevent and treat seizures, also slows pre-term labor
What is the purpose of phosphorus in the cell?
Synthesis of ATP, modulates oxygen carrying capacity of hemoglobin, metabolism of carbohydrates, fat, and protein; critical element in cell membranes
What is the tx if a patient has serum phosphorus of <1.5?
stop dextrose solutions, 0.5mm/kg NaPhos in D5W 250ml over 4h
What is the tx if a patient has serum phosphorus 1.5-2?
0.25mm/kg NaPhos in D5W 250ml over 4h
What is the tx if a patient has serum phosporus 2.1-2.4?
0.15mm/kg NaPhos in D5W 250ml over 4 h
When can KPhos be used instead of NaPhos?
for phosphate replacement if K is also low; do not exceed 10 mEq K / h
What is in 1 ml stock solution of NaPhos?
3mm Phos, 4 mEq Na
What is in 1 ml stock solution of KPhos?
3mm Phos, 4.4 mEq K
What does refeeding syndrome cause?
hypophosphatemia; phosphate is taken up rapidly into cells with glucose when glucose is given to malnutritioned pts
What are the problems with hypophosphatemia?
limits oxygen unloading, immunocompromise, muscle weakness (leading to failure to wean from ventilator)
What is the tx for hypophosphatemia?
IV supplementation in emergent cases, PO supplementation routinely, keep (phos X calcium) product < 60, mag should be replenished simultaneously
Where is calcium stored?
bone
What processes is calcium important for in the body?
cardiac function, neuromuscular function, blood coagulation
What is Ca level dependent on?
parathyroid hormone, Vit D, calcitonin
What is the corrected calcium equation?
Corrected Ca= (4-Albserum)x0.8)+Caserum
What is the replacement dose of calcium?
1 to 2 g of calcium gluconate in D5W 50ml over 1 h
What should be checked before replacing Ca?
phosphate level as serum Ca X phos should not be > 60