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Flashcards in Fluid Replacement Deck (62):
1

Body water compostition

Infants (75-85%), adult men (50-60%), adult females (45-55%)

2

Fluid type composition

intracellular (2/3), extracellular (1/3)- interstitial (3/4), Plasma (1/4)

3

Maintenance requirements

Holliday-segar calculation- 100 mL/kg first 10 kg, 50 ml/kg first 10 kg, 20 ml/kg after; or estimate ~30 mL/kg

4

Two major types of fluid

crystalloids- normal saline (.9%NaCl), half normal saline (.45% NaCl), lactated ringers, Dextrose 5% in H2O; Colloid- albumin, hetastarch, plasmanate

5

Crystalloids

provide water and sodium to maintain the osmotic gradient between extravascular and intravascular spaces

6

Normal saline

.9 % NaCl, isotonic, used most common for fluid replacement, resuscitation in septic pt, can be used to correct Na or Cl deficiencies

7

1/2 Normal saline

.45% NaCl hypotonic, use for maintenance fluids for hypernatremic pt

8

Lactate ringers

approximates human plasma regarding electrolyte concentration, used for replacement of blood loss, mainstay in laboring women

9

D5W

used for free water replacement, not a resuscitative fluid, various concentrations; 5g dextrose in 100 ml, given in liters so there is 50 g in dose

10

NaCl 3%

hypertonic saline, rarely used for hypernatremia, inc ICP, dangerous! if not used appropriately, monitor very closely, give small volumes

11

Never give what as IV fluids

sterile H2O, this is LETHAL

12

Colloids

used to increase plasma oncotic pressure and move fluid from interstitial compartment to plasma compartment, use selectively for volume expansion during extreme situations like hemorrhagic shock

13

Colloid options

albumin, blood, hetastarch

14

Sodium

normal 135-145 mEq/L, extracellular cation needed to maintain cellular integrity and osmolar gradient to maintain fluid homeostasis throughout the different fluid compartments

15

Hyponatremia

most commonly encountered electrolyte disturbance in hospitalized pts, associated w/ significant morbidity and mortality

16

pseudohyponatremia

extreme elevations of lipid or proteins, osmolality is number of particles per liter H2O, measured serum osmolality is not sig affected, calc osmalitlity will be low

17

hypertonic hyponatremia

RARE, serum [Na] falls by 1.6 mEq/l for each 100 mg/dL incremental increase in blood glucose; by correcting glucose you will correct hyponatremia

18

hypotonic hyponatremia

more than 90% of cases, access ECF volume; hypovolemic, euvolemic, hypervolemic

19

hypovolemic hyponatremia

dehydration, caused by diuretics and salt losing nephropathy, treat w/ IV fluids, hypertonic NaCl in symptomatic pts or isotonic NaCl in asymptomatic

20

SIADH

syndrome of inappropriate antidiuretic hormone, water intake exceeds the capacity of the kidneys to excrete water, inability to concentrate urine

21

Causes of SIADH

tumors, CNS disorders, head trauma, stroke, meningitis, pituitary surgery, DRUGS

22

Drugs that induce SIADH

Despressin, oxytocin, carbamazepine, antipsychotics, TCAs, cyclophosphamides, chemo, NSAIDs, Morphine

23

Isovolemic hyponatremia

will likely appear as euvolemic, slight increase in ECF, caused by glucocorticoid deficiency, hypothyroidism, psychogenic polydipsia, SIADH

24

Treatment of isovolemic hyponatremia

furosemide +3% NaCL in symptomatic pts, isotonic fluids in asymptomatic pts, fluid restrictions (if correction needed quickly)

25

Hypervolemic hyponatremia

total body water increased, seen in CHF, liver failure, renal failure, nephrotic syndromes

26

Treatment of hypervolemic hyponatremia

furosemide and judicious use of 3% NaCl in symptomatic pts, furosemide in asymptomatic

27

When treating hyponatremia, NEVER...

Correct faster than .5 mEq/L/hr or 12 mEq/L/day, it can cause osmotic demylenation

28

Vasopressin receptor antagonists

Tolvaptan (Samsca), Conivaptan (Vaprisol)

29

Tolvaptan (Samsca)

only available PO, given 10-60 mg daily, $$$

30

Conivaptan (Vaprisol)

only available IV, CI, 20 mg IV load, then 20 mg infused over 24 hrs, $$$

31

MOA of vasopressin receptor antagonists

promotes excretion of free water w/o loss of serum electrolytes resulting in net fluid loss, increased urine output, decreased urine osmoloality and restoration or normal serum Na levels

32

Safety concerns w/ vasopressin receptor antagonists

risk of correcting too fast, must be initiated in hospital, must lift fluid restriction, most places only allow nephrologist to use

33

Hypervolemic hypernatremia

caused by excessive hypertonic saline resuscitation, NaCHO3 administration, excessive table salt

34

Treating hypervolemic hypernatremia

stop hypertonic fluids and give diuretics

35

hypovolemic hypernatremia

treatment by restoring hemodynamic status first, can replace with NS even though the pt is hypernatremic

36

Potassium

hypo and hyperkalemia associated w/ fatal arrythmias, each 1 mEq/L decrease in K

37

factors affecting serum [K]

kidneys, arterial pH, insulin, B agonists, Na/K pumps

38

hypokalemia caused by

diuretics, vomiting, NG drainage, magnesium depletion

39

Goal for replacement in hypokalemia

4mEq/L, oral route preferred, less risk of overshoot; K= 3-3.9 mEq/L; 10 mEq K supplement will increase [K] by .1 mEq/L; K

40

It is impossible to correct K if

mag is low, so correct mag first, then address K

41

IV KCl

preferred if pt symptomatic or NPO, rate IV replacement limited if pt has only a peripheral IV (10 mEq/hr max), central IV can run at 20 mEq/hr, Dangerous!

42

Hypokalemia w/ 3.2 mEq/L, not symptomatic

add 30 mEq KCl to IVF, or give 40 mEq PO q6hrs x3

43

hypokalemia w/ 2.7 mEq/L and sympomatic

give KCl 40 mEq IV q4h x 3, and KCl liquid 40 mEQ PO x1 dose bolus

44

Hyperkalemia

more consequential and more rare than hypokalemia, mild 5.5-6 mEq/L. mod 6-6.9 mEq/L, severe >7; some may not have symptoms if really high, still treat!

45

Management of hyperkalemia

calcium gluconate (1 gm IVPx1 dose), Humulin R (10 units IVPx1), sodium bicarb 50 mEq IVPx1, albuterol (10 mg continuous neb), hemodialysis (4 hr session), sodium polystyrene (Kayexalate, 30 gm POx1); can do combo

46

which management of hyperkalemia only stabilizes pericardium, inc threshold

calcium gluconate

47

Which management of hyperkalemia has to be given w/ dextrose and works quickly?

Humulin R

48

which management of hyperkalemia works quickly by driving K back into the cells

sodium bicarb and albuterol

49

which management of hyperkalemia has fastest onset

hemodialysis

50

which management of hyperkalemia has slower onset, works by a resin exchange of Na for K

sodium polystyrene

51

Magnesium

needed for stabilizing macromolecule structures such as DNA/RNA and related to Ca and K metabolism; regulated by intake and kidney excretion

52

Hypomagnesemia

associated w/ disorders of the GI tract or kidneys, decreased intestinal absorption, can be caused by chronic EtOH, amphotericin, diuretics, aminoglycosides

53

Treatment of hypomagnesemia

asymptomatic- PO, milk of mag, or mag ox, will cause diarrhea; symptomatic- IV mag sulfate, 1 gram Mag sulfate= 8 gEq magnesium, infuse each gram over 1 hour, exceeding this results in renal excretion (level 1-2 give .5 mEq/kg, if

54

Calcium, organs involved w/ metabolism

bone, kidneys, intestines

55

hypocalcemia

correct for albumin, accounts for protein binding, if low albumin likely have norm Ca; if mag low fix that first

56

hypocalcemia treatment

100-300 mg Ca IV over 10 mins, 1 g CaCl or 2-3 g Calcium gluconate

57

Difference in CaCl and gluconate

CaCl contains more Ca, harder on veins; CaGL contains less Ca, easier on veins

58

Hypercalcemia

seen in CA pts and hyperparathyroidism, caused by dec renal elimination, inc bone resorption, inc GI absorption

59

Hypercalcemia tx

calcitonin, most common, loop diuretic, short term (lasix inc urinary excretion), bisphosphonates- pamidronate (Aredia-IV infusion over several hours, short term only, very effective)

60

Phosphorus

critical for protein, fat and carb metabolism, modulates O2 carrying capacity of hemoglobin

61

hypophoshatemia

1mmol=1.33 mEq sodium and 1.47 Eq potassium, replace orally or enteraly w/ neutra phos packet or Kphos tab q6-8h, also NaPhos/Kphos parenterally

62

Hypophoshatemia levels/treatment

mild (2.3-3 mg/dL)- .32 mM/kg q4-6h; mod (1.6-2.2 mg/dL)- .64 mM/kG q4-6h; severe (