Lecture 10 - Fluids & Electrolytes Flashcards

1
Q

how to calculate mEq

A

( Mass (mg) X valence) / (molecular weight)

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2
Q

mOsm/L of NaCl?

A

308 mOsm/L

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3
Q

Normal plasma osmolality?

A

~ 270-295 mOsm/L

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4
Q

Isotonic Solutions

A

270-300 mOsm/L

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5
Q

Hypotonic solutions

A

< 270 mOsm/L

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6
Q

Hypertonic solutions

A

> 300 mOsm/L

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7
Q

Why should significantly hypotonic fluids ( < 154 mOsm/L) not be admin directly to patients?

A

can cause cellular swelling and cell death

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8
Q

What makes solutions Iso, Hypo, Hypertonic?

A
Hypertonic = due to Electrolyte balances
Hypotonic = due to have fraction of electrolyte of normal solution
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9
Q

Total Body Water Calculation

A

~ 50% for women (of total body weight)
~ 60% for men (of total body weight)

also ~73% of Lean body mass

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10
Q

Osmolar Gap Calculation

A

Measured Na+ mEq/L + {[(measured glucose - 100)/100] X 1.6}

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11
Q

Osmolar Gap seen when pts have which symptoms?

A
Severe Hyperglycemia
Hyperlipidemia
Azotemia/uremia
Mannitol infusion
Toxic alcohols
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12
Q

Causes of Osmolar Gap

A

high glucose or low sodium

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13
Q

Neonate fluid replacement calc (< 10kg)

A

100ml/Kg

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14
Q

Pediatric fluid replacement calc ( 10-20kg)

A

1000ml + 50ml/each kg between 10-20kg

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15
Q

Adolescent/Adult fluid replacement calc (> 20kg)

A

1500ml + 20ml/each kg > 20kg

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16
Q

Mild Dehydration Therapy

A

Replace over 8-24hrs
Provide additional 6-8oz per episode of diarrhea

ORT = Oral rehydration therapy
too much glucose can cause osmotic diarrhea
Optimal mix of fluid, electrolytes, carbs

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17
Q

Examples of Oral Rehydration solutions

A
WHO/UNICEF ORT
Ceralyte 50,70,90 (# = amount of sodium)
Infalyte
Naturalyte
Pedialyte Liquid and Freezer pops
Rehydrate
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18
Q

Moderate/Severe Dehydration Therapy

A

Req hospitalization and IV rehydration

Txm must include water deficit + maintenance fluid needs + ongoing abnormal/excessive losses

** Fluids will distribute into body fluid compartments based on osmolarity of the solution and the effective free water content**

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19
Q

Common causes of volume overload

A

HF
Liver cirrhosis
Nephrotic Syndrome

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20
Q

Acidemia

A

pH < 7.35 = higher amounts of bicarb, or lower lvls of C02

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21
Q

Alkalosis

A

pH > 7.45

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22
Q

Pulmonary & Metabolic Regulatory Mechanism

A
respiratory = if issue is in lungs
Metabolic = if issue is in kidneys
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23
Q

General Na reference range?

A

135-146mEq/L

symptoms tend not develop until lvls are above/below by 10mEq/L

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24
Q

Hyponatremia

A

Na lvl < 135

Severe < 125

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25
Q

Where do Osmotic diuretics work?

A

PCT

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26
Q

Where do Loop diuretics work?

A

Loop of Henle

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27
Q

Where do ADH & Vasopressin antagonists work?

A

Collecting duct

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28
Q

Where do Thiazide diuretics work?

A

DCT

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29
Q

Examples of Osmotic diuretics

A

Mannitol, urea, glycerol

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30
Q

How do osmotic diuretics wok?

A

create osmotic gradient and inc water excretion

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31
Q

What are osmotic diuretics used for clinically?

A

reduce increased intracranial pressure, intraocular pressure, and promote removal of toxins

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32
Q

Example of Carbonic Anhydrase Inhibitor

A

Acetazolamide, acts mainly in proximal tubule

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33
Q

IV to PO furosemide?

A

20mg IV = 40 MG PO

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34
Q

Diuretic with risk of hyponatremia?

A

Thiazide diuretics

35
Q

Spironolactone and eplerenone are antagonists for what?

A

Aldosterone

They’re potassium sparring diuretics

Generally weak activity

36
Q

Conivaptan & Tolvaptan are….

A

Vasopressin Antagonists (ADH)

increase serum osmolality & Na but don’t alter Na excretion

37
Q

Conivaptan receptor antagonist at….

A

V1a and V2

38
Q

Tolvaptan receptor antagonist at…

A

Selective V2

preferred

39
Q

Osmolarity of D5W only

A

252 = hypotonic

40
Q

Osmolarity 0.9% NaCl

A

308 = isotonic

41
Q

Osmolarity 0.45% NaCl

A

154 = hypotonic

42
Q

Osmolarity D5W + 0.225% NaCl

A

329 = hypertonic

43
Q

Osmolarity D5W + 0.45% NaCL

A

406 = hypertonic

44
Q

Lactated Ringer

A

273 = Isotonic

45
Q

Plasma-Lyte

A

294 = isotonic

46
Q

causes of Hyponatremia

A

Loss of sodium, gain of water or both

47
Q

Mild Hypoatremia

A

126-135

typically asymptomatic/non-specific

HA, Disorientation, mild confusion, blurry vison, N/V

48
Q

Moderate Hyponatremia

A

120-125

range from mild-profound confusion, no concern of seizures

49
Q

Severe hyponatremia

A

< 120

may include stupor/coma, severe neurologic changes

50
Q

Hypovolemic Hyponatremia

A

Excessive electrolyte-rich solute loss relative to TBW loss

51
Q

Euvolemic Hyponatremia

A

slight decrease/normal total body Na and normal/slightly elevated TBW (no fluid overload)

common due to SIADH

52
Q

Hypervolemic Hyponatremia

A

excessive overload leads to dilution effect in the serum

endurance athletes

53
Q

Correction rates for Hyponatremia

A

as low was 1-2 mEq/L per hour

Typical Max = 6 mEq/L in 6hrs, 12 mEq/L in 24hrs, 18 mEq/L in 48hrs

avoid rapid over correction, you’d avoid sodium based products if you do over correct

54
Q

Hypovolemic Hyponatremia treatment

A

Mild/moderate = normal saline + lactated ringer

More severe = 3% hypertonic saline

55
Q

concern with rapidly correcting patients sodium?

A

Osmotic Demylenation

56
Q

Euvolemic or Hypervolemic Hyponatremia treatment

A

Mild/moderate = volume restriction

Severe = bolus hypertonic saline prioritized over volume restriction 1st 12-24hrs

57
Q

If fluid restriction falls in Euvolemic/Hypervolemic then what….

A

Try loop diuretics, IV 20-40 Furosemide q6/12hrs

Vasopressin receptor antagonist

58
Q

Only free water available in hospital?

A

Dextrose

59
Q

Hypernatremia treatment

A

minimize sodium taking in
give them volume (“Free Water” = electrolyte free) = Dextrose infusion

want it to be sodium free

60
Q

Hypovolemia Hypernatremia treatment

A

Isotonic solution over 2-4 days at a low rate

61
Q

Hypervolemia Hypernatremia treatment

A

Loop diuresis elim excess fluid and sodium

62
Q

hypochloremia lvls

A

< 97 mEq/L

63
Q

hypochloremia treatment

A

chloride containing solution

64
Q

Hyperchloremia lvls

A

> 108 mEq/L

65
Q

Hyperchloremia treatments

A

D/c or reduce causative agent

little treatment options

sodiumbicarb can be given as buffer

66
Q

Potassium range

A

3.5-5 mEq/L

67
Q

Hypokalemia lvls

A

< 3.4 mEq/L

Give potassium, but less worrisome than Hyperkalemia

68
Q

Hyperkalemia lvls

A

> 5 mEq/L

can cause arrhythmia when > 6

69
Q

Hyperkalemia treatment

A

1st give Calcium gluconate 1-2g IV push if they are symptomatic or have ECG changes (stabilizes cardiac cell membranes)

Then reduce/remove the potassium

70
Q

Acute Hyperkalemia Treatment

A

Reduce: Insulin, Sodium Bicarb, Albuterol

To remove: Kayexalate ( sodium polystyrene sulfonate)

Hemodialysis = last stop

71
Q

Chronic Hyperkalemia Treatment

A

Patiromer (Veltassa) or sodium zirconium cyclosilicate (Lokelma)

72
Q

Phosphorus range

A

2.7-4.5 mg/dL

73
Q

Hypophosphatemia

A

< 2.6 mg/dL

74
Q

Hyperphosphatemia

A

> 4.5 mg/dL

commonly seen with CKD

75
Q

Hypophosphatemia treatment

A

Mild (2-2.5) or moderate (1-1.9) = oral supplements if functional GI

Severe (< 1) = IV

76
Q

Hyperphosphatemia Treatment

A

Treat underlying conditions

give drugs that bind to phosphate and remove it

** tied to calcium, so if have hypercalcemia then avoid calcium binder **

77
Q

Calcium ranges

A

8.5 - 10.2 mg/dL

78
Q

Hypocalcemia

A

< 8.5 mg/dL

79
Q

Hypocalcemia treament

A

Acute: Calcium glucoante > Calcium chloride
Chronic: 1-2g/elemental per day

80
Q

Hypercalcemia

A

> 10.2 mg/dL

1st clinical thought = cancer

81
Q

Hypercalcemia acute treatment

A

1st step = hydration

Severe: 200-300 ml/hr of NS for 2-6L

Bisphosphate & RANK therapy = store calcium back into bones

82
Q

Hypercalcemia chronic treatment

A

Cincalcet
Frequent Bisphosphonates
Denosumab

83
Q

Hypomagnesemia

A

< 1.5 or lower

Treatment: replace…the more severe the higher the dose

Oral = mild/moderate, IV = severe

84
Q

Hypermagnesemia

A

can give Calcium chloride