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Flashcards in Fluids and Electrolytes Deck (169):
1

What are the two major body fluid compartments?

1. Intracellular
2. Extracellular

2

What are the two sub compartments of extracellular fluid?

1. Interstitial
2. Intravascular

3

What percentage of body weight is in fluid?

60%

4

What percentage of body fluid is intracellular?

66%

5

What percentage of body fluid is extracellular?

33%

6

On average, what percentage of body weight does blood account for in adults?

7%

7

How many liters of blood are in a 70-kg man?

5 liters

8

What is the daily water requirement?

30-35 mL/kg

9

What is the daily potassium requirement?

1 mEq/kg

10

What is the daily chloride requirement?

1.5 mEq/kg

11

What is the daily sodium requirement?

1-2 mEq/kg

12

What are the levels and sources of normal daily water loss?

Urine: 1200-1500 mL (25-30 mL/kg)
Sweat: 200-400 mL
Respiratory losses: 500-700 mL
Feces: 100-200 mL

13

What are the levels and sources of normal daily electrolyte loss?

Sodium and potassium: 100 mEq
Chloride: 150 mEq

14

What are the levels of sodium and chloride in sweat?

40 mEq/L

15

What is the major electrolyte in colonic feculent fluid?

Potassium: 65 mEq/L

16

What is the physiologic response to hypovolemia?

Sodium/water retention via renin/aldosterone; water retention via ADH; vasoconstriction via angiotensin II and sympathetics; low urine output and tachycardia (early), hypotension (late)

17

What is third spacing?

Fluid accumulation in the interstitial of tissues, as in edema (e.g. loss of fluid into the interstitium and lumen of a paralytic bowel following surgery)

18

When does third-spacing occur postoperatively?

Third-spaced fluid tends to mobilize back into the intravascular space around POD #3 (switch to hypotonic fluid and decrease IV rate)

19

What are the classic signs of third spacing?

Tachycardia, decreased urine output

20

What is the treatment for third spacing?

IV hydration with isotonic fluids

21

What are the surgical causes of metabolic acidosis?

Loss of bicarbonate (e.g. diarrhea, ileus, fistula, high-output ileostomy, carbonic anhydrase inhibitors).
Increase in acids (e.g. lactic acidosis from ischemia, ketoacidosis, renal failure, necrotic tissue).

22

What are the surgical causes of hypochloremic alkalosis?

NGT suction, loss of gastric HCl through vomiting/NGT

23

What are the surgical causes of metabolic alkalosis?

Vomiting, NG suction, diuretics, alkali ingestion, mineralocorticoid excess

24

What are the surgical causes of respiratory acidosis?

Hypoventilation (e.g. CNS depression, drugs, PTX, pleural effusion, parenchymal lung disease, acute airway obstruction)

25

What are the surgical causes of respiratory alkalosis?

Hyperventilation (e.g. anxiety, pain, fever, wrong ventilator settings)

26

What is the classic acid-base finding with significant vomiting or NGT suctioning?

Hypokalemic hypochloremic metabolic alkalosis

27

Why hypokalemia with NGT suctioning?

Loss of HCl causes alkalosis, driving K into cells

28

What is the treatment for hypokalemic hypochloremic metabolic alkalosis?

IVF, Cl/K replacement

29

What is paradoxic alkalotic aciduria?

Seen in severe hypokalemic, hypovolemic, hypochloremic metabolic alkalosis with paradoxic metabolic alkalosis of serum and acidic urine

30

How does paradoxic alkalotic aciduria occur?

H is lost in the urine in exchange for Na in an attempt to restore volume

31

With paradoxic alkalotic aciduria, why is H preferentially lost?

H is exchanged preferentially into the urine instead of K because of the low concentration of K

32

What can be followed to assess fluid status?

Urine output, base deficit, lactic acid, vital signs, weight changes, skin turgor, JVD, mucosal membranes, rales, central venous pressure, PCWP, CXR

33

With hypovolemia, what changes occur in vital signs?

Tachycardia, tachypnea, initial rise in diastolic BP because of peripheral vasoconstriction with subsequent decrease in both systolic and diastolic BP

34

What are the insensible fluid losses?

Loss of fluid not measured: feces, breathing (increased with fever, tachypnea), sweat (increased with fever)

35

What quantity of bile is secreted daily?

1000 mL

36

What quantity of gastric secretions are secreted daily?

2000 mL

37

What quantity of pancreatic secretions are secreted daily?

600 mL

38

What quantity of small intestinal secretions are secreted daily?

3000 mL

39

What quantity of saliva is secreted daily?

1500 mL

40

What comprises NS?

154 mEq of Cl
154 mEq of Na

41

What comprises 1/2 NS?

77 mEq of Cl
77 mEq of Na

42

What comprises 1/4 NS?

39 mEq of Cl
39 mEq of Na

43

What comprises lactated Ringer's?

130 mEq of Na
109 mEq of Cl
28 mEq lactate
4 mEq K
3 mEq Ca

44

What comprises D5W?

5% dextrose (50 g) in water

45

What accounts for tonicity?

Mainly electrolytes (thus NS and LR are both isotonic)

46

What happens to the lactate in LR in the body?

Converted into bicarbonate, thus LR cannot be used as a maintenance fluid because patients would become alkalotic

47

What is the IVF replacement for gastric fluid loss (NGT)?

D5 1/2 NS + 20 KCl

48

What is the IVF replacement for biliary fluid loss?

LR +/- sodium bicarbonate

49

What is the IVF replacement for pancreatic fluid loss?

LR +/- sodium bicarbonate

50

What is the IVF replacement for small bowel fluid loss (ileostomy)?

LR

51

What is the IVF replacement for colonic fluid loss (diarrhea)?

LR +/- sodium bicarbonate

52

What is the 100/50/20 rule?

Maintenance IV fluids for a 24-hour period:
100 mL/kg for the first 10 kg
50 mL/kg for the next 10 kg
20 mL/kg for every kg over 20

53

What is the 4/2/1 rule?

Maintenance IV fluids for hourly rate:
4 mL/kg for the first 10 kg
2 mL/kg for the next 10 kg
1 mL/kg for every kg over 20

54

What is the maintenance for a 70-kg man?

110 mL/hr

55

What is the common adult maintenance fluid?

D5 1/2 NS with 20 mEq KCl/L

56

What is the common pediatric maintenance fluid?

D5 1/4 NS with 20 mEq KCl/L (children have decreased ability to concentrate urine)

57

Why should sugar be added to maintenance fluid?

To inhibit muscle breakdown

58

What is the best way to assess fluid status?

Urine output (unless the patient has cardiac or renal dysfunction, in which case central venous pressure or wedge pressure is often used)

59

What is the minimal urine output for an adult on maintenance IV fluids?

30 mL/hr (0.5 mL/kg/hr)

60

What is the minimal urine output for an adult trauma patient?

50 mL/hr

61

How many mL are in 12 oz?

356 mL

62

How many mL are in 1 oz?

30 mL

63

How many mL are in 1 tsp?

5 mL

64

What are common isotonic fluids?

NS, LR

65

What is a bolus?

Volume of fluid given IV rapidly.
Used for increasing intravascular volume, and isotonic fluids should be used.

66

Why not combine bolus fluids with dextrose?

Hyperglycemia may result

67

What is the possible consequence of hyperglycemia in the patient with hypovolemia?

Osmotic diuresis

68

Why not combine bolus fluids with a significant amount of potassium?

Hyperkalemia may result

69

Why should isotonic fluids be given for resuscitation?

If hypotonic fluid is given, the tonicity of the intravascular space will be decreased and water will freely diffuse into the interstitial and intracellular spaces (thus, use isotonic fluids to expand the intravascular space)

70

What portion of 1 L NS will stay in the intravascular space after a laparotomy?

In 5 hours, only 200 mL will remain in the intravascular space

71

What is the most common trauma resuscitation fluid?

LR

72

What is the most common postoperative IV fluid after laparotomy?

LR or D5LR for 24-36 hours, followed by maintenance fluid

73

After a laparotomy, when should a patient's fluid be mobilized?

Classically, POD #3 (the patient begins to mobilize the third-space fluid back into the intravascular space)

74

What IVF is used to replace duodenal or pancreatic fluid loss?

LR (bicarbonate loss)

75

What is a common cause of electrolyte abnormalities?

Lab error

76

What is a major extracellular cation?

Na

77

What is a major intracellular cation?

K

78

What is the normal range for potassium level?

3.5-5.0 mEq/L

79

What are the surgical causes of hyperkalemia?

Iatrogenic overdose, blood transfusion, renal failure, diuretics, acidosis, tissue destruction, hemolysis

80

What are the signs and symptoms of hyperkalemia?

Decreased DTRs or areflexia, weakness, paresthesias, paralysis, respiratory failure

81

What are the ECG findings with hyperkalemia?

Peaked T waves, depressed ST segment, prolonged PR, wide QRS, bradycardia, ventricular fibrillation

82

What are the critical values for potassium?

K > 6.5

83

What is the urgent treatment for hyperkalemia?

IV calcium (cardioprotective); ECG monitoring; sodium bicarbonate IV (alkalosis drives K intracellularly); glucose and insulin; albuterol; sodium polystyrene sulfonate (Kayexalate) and furosemide (Lasix); dialysis

84

What is the non-acute treatment for hyperkalemia?

Furosemide (Lasix), sodium polystyrene sulfonate (Kayexalate)

85

What is the acronym for the treatment of acute symptomatic hyperkalemia?

CB DIAL K:
Calcium, Bicarbonate, Dialysis, Insulin/dextrose, Albuterol, Lasix, Kayexalate

86

What is pseudohyperkalemia?

Spurious hyperkalemia as a result of falsely elevated K in sample from sample hemolysis

87

What acid-base change lowers the serum potassium?

Alkalosis

88

What nebulizer treatment can help lower K level?

Albuterol

89

What are the surgical causes of hypokalemia?

Diuretics, certain antibiotics, steroids, alkalosis, diarrhea, intestinal fistulae, NG aspiration, vomiting, insulin, insufficient supplementation, amphotericin

90

What are the signs and symptoms of hypokalemia?

Weakness, tetany, N/V, ileus, paresthesia

91

What are the ECG findings with hypokalemia?

Flattening of T waves, U waves, ST segment depression, PAC, PVC, atrial fibrillation

92

What is the rapid treatment for hypokalemia?

IV KCl

93

What is the maximum amount of KCl that can be given through a peripheral IV?

10 mEq/hr

94

What is the maximum amount of KCl that can be given through a central line?

20 mEq/hr

95

What is the chronic treatment for hypokalemia?

PO KCl

96

What is the most common electrolyte-mediated ileus in the surgical patient?

Hypokalemia

97

What electrolyte condition exacerbates digitalis toxicity?

Hypokalemia

98

What electrolyte deficiency can actually cause hypokalemia?

Low magnesium

99

What electrolyte must you replace first before replacing potassium?

Magnesium

100

Why does hypomagnesemia make replacement of potassium with hypokalemia nearly impossible?

Hypomagnesemia inhibits K reabsorption from the renal tubules

101

What is the normal range for sodium level?

135-145 mEq/L

102

What are the surgical causes of hypernatremia?

Inadequate hydration, diabetes insipidus, diuresis, vomiting, diarrhea, diaphoresis, tachypnea, iatrogenic (e.g. TPN)

103

What are the signs and symptoms of hypernatremia?

Seizures, confusion, stupor, pulmonary or peripheral edema, tremors, respiratory paralysis

104

What is the usual treatment supplementation given slowly over days for hypernatremia?

D5W, 1/4 NS or 1/2 NS

105

How fast should you lower the sodium level in hypernatremia?

Guideline is < 12 mEq/L per day

106

What is the major complication of lowering the sodium level too fast with hypernatremia?

Seizures (not central pontine myelinolysis)

107

What are the surgical causes of hypovolemic hyponatremia?

Diuretic excess, hypoaldosteronism, vomiting, NG suction, burns, pancreatitis, diaphoresis

108

What are the surgical causes of euvolemic hyponatremia?

SIADH, CNS abnormalities, drugs

109

What are the surgical causes of hypervolemic hyponatremia?

Renal failure, CHF, liver failure, iatrogenic fluid overload

110

What are the signs and symptoms of hyponatremia?

Seizures, coma, N/V, ileus, lethargy, confusion, weakness

111

What is the treatment for hypovolemic hyponatremia?

NS IV, correct underlying cause

112

What is the treatment for euvolemic hyponatremia?

If SIADH: furosemide and NS acutely, fluid restriction

113

What is the treatment for hypervolemic hyponatremia?

Dilutional fluid restriction and diuresis

114

How fast should you increase the sodium level in hyponatremia?

Guideline < 12 mEq/L per day

115

What may occur if you correct hyponatremia too quickly?

Central pontine myelinolysis

116

What are the signs and symptoms of central pontine myelinolysis?

1. Confusion
2. Spastic quadriplegia
3. Horizontal gaze paralysis

117

What is the most common cause of mild postoperative hyponatremia?

Fluid overload

118

What is pseudohyponatremia?

Spurious lab value of hyponatremia as a result of hyperglycemia, hyperlipidemia, or hyperproteinemia

119

What are the causes of hypercalcemia?

CHIMPANZEES:
Calcium supplementation IV; Hyperparathyroidism, Hyperthyroidism; Immobility, Iatrogenic (thiazide diuretics); Mets, Milk alkali syndrome; Paget's disease (bone); Addison's disease, Acromegaly; Neoplasm (colon, lung, breast, prostate, multiple myeloma); Zollinger-Ellison syndrome (MEN-I); Excessive vitamin A; Excessive vitamin D; Sarcoid

120

What are the signs and symptoms of hypercalcemia?

"Stones, bones, abdominal groans, and psychiatric overtones"
Polydipsia, polyuria, constipation

121

What are the ECG findings with hypercalcemia?

Short QT interval, prolonged PR interval

122

What is the acute treatment of hypercalcemic crisis?

Volume expansion with NS, diuresis with furosemide (not thiazides)

123

What are options (other than volume expansion and furosemide) for lowering the calcium level?

Steroids, calcitonin, bisphosphonates (pamidronate), mithramycin, dialysis (last resort)

124

How can the calcium level be determined with hypoalbuminemia?

(4 - measured albumin level) X 0.8, then add this value to the measured calcium level

125

What are the surgical causes of hypocalcemia?

Short bowel syndrome, intestinal bypass, vitamin D deficiency, sepsis, acute pancreatitis, osteoblastic metastasis, aminoglycosides, diuretics, renal failure, hypomagnesemia, rhabdomyolysis

126

What is Chvostek's sign?

Facial muscle spasm with tapping of facial nerve

127

What is Trousseau's sign?

Carpal spasm after occluding blood flow in forearm with blood pressure cuff

128

What are the signs and symptoms of hypocalcemia?

Chvostek's sign, Trousseau's sign, perioral paresthesia (early), increased DTRs (late), confusion, abdominal cramps, laryngospasm, stridor, seizures, tetany, psychiatric abnormalities (e.g. paranoia, depression, hallucinations)

129

What are the ECG findings with hypocalcemia?

Prolonged QT and ST interval (peaked T waves are also possible, as in hyperkalemia)

130

What is the acute treatment of hypocalcemia?

IV calcium gluconate

131

What is the chronic treatment of hypocalcemia?

PO calcium, vitamin D

132

What is the possible complication of infused calcium if the IV infiltrates?

Tissue necrosis (never administer peripherally unless absolutely necessary)

133

What is the best way to check the calcium level in the ICU?

Check ionized calcium

134

What is the normal range for magnesium level?

1.5-2.5 mEq/L

135

What is the surgical cause of hypermagnesemia?

TPN, renal failure, IV over supplementation

136

What are the signs and symptoms of hypermagnesemia?

Respiratory failure, CNS depression, decreased DTRs

137

What is the treatment for hypermagnesemia?

IV calcium gluconate, insulin and glucose, dialysis (similar for hyperkalemia), furosemide (Lasix)

138

What are the surgical causes of hypomagnesemia?

TPN, hypocalcemia, NG suction, aminoglycosides, renal failure, diarrhea, vomiting

139

What are the signs and symptoms of hypomagnesemia?

Increased DTRs, tetany, asterixis, tremor, Chvostek's sign, ventricular ectopy, vertigo, tachycardia, dysrhythmias

140

What is the acute treatment for hypomagnesemia?

IV MgSO4

141

What is the chronic treatment for hypomagnesemia?

PO Magnesium oxide

142

Hypomagnesemia may make it impossible to correct what other electrolyte abnormality?

Hypokalemia

143

What are the surgical causes of hyperglycemia?

Diabetes (poor control), infection, stress, TPN, drugs, lab error, drawing over IV site, somatostatinoma, glucagonoma

144

What are the signs and symptoms of hyperglycemia?

Polyuria, hypovolemia, confusion, coma, polydipsia, ileus, DKA (Kussmaul breathing), abdominal pain, hyporeflexia

145

What is the treatment for hyperglycemia?

Insulin

146

What is the Weiss protocol?

Sliding scale insulin

147

What is the goal glucose level in the ICU?

80-110 mg/dL

148

What are the surgical causes of hypoglycemia?

Excess insulin, decreased caloric intake, insulinoma, drugs, liver failure, adrenal insufficiency, gastrojejunostomy

149

What are the signs and symptoms of hypoglycemia?

Sympathetic response (diaphoresis, tachycardia, palpitations), confusion, coma, headache, diplopia, neurologic deficits, seizures

150

What is the treatment for hypoglycemia?

Glucose (IV or PO)

151

What is the normal range for phosphorus level?

2.5-4.5 mg/dL

152

What are the signs and symptoms of hypophosphatemia?

Weakness, cardiomyopathy, neurologic dysfunction (ataxia), rhabdomyolysis, hemolysis, poor pressor response

153

What is a complication of severe hypophosphatemia?

Respiratory failure

154

What are the causes of hypophosphatemia?

GI losses, inadequate supplementation, medications, sepsis, alcohol abuse, renal loss

155

What is the critical value for phosphorus level?

< 1.0 mg/dL

156

What is the treatment for hypophosphatemia?

Supplement with sodium phosphate or potassium phosphate IV

157

What are the signs and symptoms of hyperphosphatemia?

Calcifications (ectopic), heart block

158

What are the causes of hyperphosphatemia?

Renal failure, sepsis, chemotherapy, hyperthyroidism

159

What is the treatment for hyperphosphatemia?

Aluminum hydroxide (binds phosphate)

160

If hyperkalemia is left untreated, what can occur?

Ventricular tachycardia or fibrillation

161

Which electrolyte is an inotrope?

Calcium

162

What are the major cardiac electrolytes?

Potassium (dysrhythmias), magnesium (dysrhythmias), calcium (dysrhythmias, inotrope)

163

Which electrolyte must be monitored closely in patients on digitalis?

Potassium

164

What is the most common cause of electrolyte-mediated ileus?

Hypokalemia

165

What is a colloid fluid?

Protein-containing fluid (albumin)

166

What is the rationale for using an albumin-furosemide "sandwich"?

Albumin will pull interstitial fluid into the intravascular space and the furosemide will then help excrete the fluid as urine

167

An elderly patient goes into CHF on POD #3 after a laparotomy. What is going on?

Mobilization of the third-space fluid into the intravascular space, resulting in fluid overload and resultant CHF

168

What fluid is used to replace NGT aspirate?

D5 1/2 NS with 20 KCl

169

What electrolyte is associated with succinylcholine?

Hyperkalemia