FLUIDS-AB balance Flashcards

1
Q

What are 6 goals of perioperative fluid management

A
  1. Euvolemia
  2. CO (preload)
  3. O2-carrying capacity
  4. A-B balance
  5. Electrolyte balance
  6. Coagulation status
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2
Q

What percentage of body weight is water

A

60% (42 L in the 70-kg standard pt)

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3
Q

What percentage of total body weight are the following
Intracellular volume
Extracellular volume

A

IC vol = 40% TBW (28 L)

EC vol = 20% TBW (14 L)

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4
Q

What are the 3 major ions of the intracellular fluid

A

K+
Mg++
PO4–

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5
Q

What are the 4 major ions of the extracellular fluid

A

Na+
Ca++
Cl=
HCO3-

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6
Q

What are the divisions of ECF and their percentage of total body water

A

Interstitial fluid = 16% or 11 L

Plasma fluid = 4% or 3 L

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7
Q

How do neonates differ in total body water percentage

A

They have a higher TBW% by weight

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8
Q

How do females, the obese, and the elderly differ in total body water percentage

A

They have a lower TBW% by weight

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9
Q

What are 2 forces that move fluid from the capillary to the interstitial space

A

Pc = Capillary hydrostatic pressure (pushes fluid out)

pi if = interstitial oncotic pressure (pulls fluid out)

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10
Q

What are 2 forces that move fluid from the interstitial space into the capillary

A

Pif = interstitial hydrostatic pressure (pushes fluid in)

pi c = capillary oncotic pressure (pulls fluid in)

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11
Q

What is the equation for net filtration pressure at the capillary

A

NFP = (Pc - Pif) - (pic - piif)

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12
Q

What actions occurs with the following net filtration pressures in the capillaries
NFP > 0
NFP < 0

A

NFP > 0 = fluid EXITS capillary

NFP < 0 = fluid is pulled INTO capillary

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13
Q

What are 4 conditions that impair the integrity of glycocalyx in the capillary

A
  1. Sepsis
  2. Ischemia
  3. DM
  4. Major vascular surgery
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14
Q

What happens when the glycocalyx is disrupted in the capillary

A

It contributes to capillary leak and accumulation of fluid and debris in the interstitial space
This reduces tissue oxygenation

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15
Q

What makes up blood volume

A

The sum of plasma volume and blood cell volume

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16
Q

What is the hematocrit composed of

A

The fraction of the blood volume that is occupied by erythrocytes

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17
Q

What factors increase Hct

A

Increased number of RBCs (polycythemia)

Decreased plasma volume (hypovolemia)

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18
Q

What factors decrease Hct

A

Decreased number of RBCs (anemia)

Increased plasma volume (hemodilution)

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19
Q

What is the purpose of the lymphatic system

A

Scavenge and remove fluid, protein, bacteria, and debris from the interstitium via negative pressure

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20
Q

What causes edema in relation to the lymphatic system

A

When the rate of interstitial fluid accumulation exceeds the rate of removal by the lymphatics

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21
Q

How is lymph returned to circulatory system

A

Via the thoracic duct at the juncture of the internal jugular and subclavian vein

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22
Q

What is the significance of the left vs right thoracic ducts and venous access

A

The ducts can be injured during venous cannulation

The left side is at greater risk of chylothorax because it is larger

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23
Q

Define osmosis

A

The net movement of water across a semipermeable membrane

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24
Q

What are 2 factors that affect osmosis

A
  1. Solute concentration determine direction of water movement
  2. Water moves from areas of low to high solute concentration
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25
Q

Define diffusion

A

the net movement of a substance from an area of higher concentration to an area of lower concentration across a fully permeable membrane (both water and solute pass)

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26
Q

Define osmotic pressure

A

The pressure of a solution against a semipermeable membrane that prevents water from diffusing across that membrane

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27
Q

What is osmotic pressure a function of

A

The number of osmotically active particles in a solution NOT their molecular weights

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28
Q

What is an osmole

A

The number of osmotically active particles in a solution

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29
Q

How are osmolarity and osmolality similar

A

They both measure the concentration of particles (osmoles) in a solution

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30
Q

What is osmolarity

A

Osmoles per liter of solution (mOsm/L of total solution)

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31
Q

What is osmolality

A

Osmoles per kilogram of solvent (mOsm/kg of H2O)

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32
Q

What is the equation for plasma osmolarity

A

Osmolarity = 2(Na+) + (glucose/18) + (BUN/2.8)

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33
Q

What factors are included in the calculation of plasma osmolarity

A

Na+
Glucose
BUN

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34
Q

List solutions that are hypotonic

A

NaCl 0.45%

D5W

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35
Q

What is the effect of hypotonic solutions

A

Water enters and cells swell

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36
Q

List crystalloids that are isotonic

A

NaCl 0.9%
LR
Plasmalyte A

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37
Q

List colloids that are isotonic

A

Albumin 5%
Voluven 6%
Hespan 6%

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38
Q

List crystalloids that are hypertonic

A

NaCl 3%
D5 NaCl 0.9%
D5 NaCl 0.45%
D5 LR

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39
Q

Which colloid is a hypertonic solution

A

Dextran 10%

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40
Q

What is the effect of hypertonic solutions

A

Water moves out of cells and they shrink

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41
Q

Why is D5W a hypotonic solution

A

The glucose is metabolized to CO2 and H2O adding to free water

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42
Q

How does administration of hypotonic solutions affect ICF, ECF, and osmolarity

A
ICF = volume increase, osmolarity decreased
ECF = volume increased, osmolarity decreased
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43
Q

How does administration of isotonic solutions affect ICF, ECF, and osmolarity

A
ICF = volume and osmolarity remain the same
ECF = volume increase, osmolarity same
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44
Q

How does administration of hypertonic solutions affect ICF, ECF, and osmolarity

A
ICF = decreased volume, increased osmolarity
ECF = increased volume, increased osmolarity
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45
Q

What are the benefits of dextran 40 on blood viscosity

A

It reduces viscosity and improves microcirculatory flow in vascular surgery

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46
Q

What effect does albumin have on inflammation

A

It has anti-inflammatory properties

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47
Q

What is the replacement ratio of crystalloid vs colloid

A
Crystalloid = 3:1 
Colloid = 1:1
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48
Q

What is a disadvantage of albumin

A

It binds with Ca++ and can lead to hypocalcemia

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49
Q

What is the FDA black box warning for synthetic colloids

A

Risk of renal injury

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50
Q

How can coagulopathy related to colloids be minimized

A

Don’t exceed 20 mL/kg

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51
Q

Which colloids have the greatest risk of coagulopathy

A

Dextran > hetastarch > hextend

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52
Q

Which colloid has the greatest anaphylactic potential

A

Dextran

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53
Q

What are disadvantages of fluid replacement with crystalloids

A
  1. Limited ability to expand plasma volume
  2. Higher potential for peripheral edema
  3. Dilutional effect on coagulation factors
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54
Q

What imbalance can occur with large volumes of NaCl

A

Hyperchloremic metabolic acidosis

Increased Cl- => Increased HCO3- excretion by kidneys

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55
Q

What is the most abundant intracellular cation

A

Potassium

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56
Q

What is the role of potassium as an intracellular cation

A
  1. Regulates resting membrane potential of nervous tissue, skeletal muscle, and cardiac muscle
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57
Q

How does hypo vs hyperkalemia affect membrane potentials

A

Hypokalemia = hyperpolarizes membranes, making it harder to depolarize

Hyperkalemia = increases resting membrane potential, making depolarization easier

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58
Q

Which organ regulates potassium homeostasis

A

The kidneys

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59
Q

What 5 medications and conditions can shift K+ intracellularly causing hypokalemia

A
  1. Insulin + D50
  2. Hyperventilation
  3. HCO3
  4. Beta-2 agonist (albuterol)
  5. Hypokalemic periodic paralysis
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60
Q

What 4 medications or conditions can shift K+ extracellularly causing hyperkalemia

A
  1. Acidosis
  2. Succinylcholine
  3. Beta-blockers
  4. Hyperkalemic periodic paralysis
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61
Q

What are 3 drugs that can impair potassium excretion from the kidneys

A
  1. NSAIDs
  2. Spironolactone
  3. Triamterene
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62
Q

What are symptoms of hypokalemia

A

Skeletal muscle cramps and weakness that can lead to paralysis

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63
Q

How can hyperkalemia present

A

Cardiac rhythm disturbances

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64
Q

Describe the EKG changes with hypokalemia

A

PR interval = LONG
QT interval = LONG
T wave = FLAT
U wave present

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65
Q

Describe the EKG changes with hyperkalemia

A
EKG change = K+ concentration:
Peaked T waves = 5.5-6.5
P wave flattening, PR prolongation = 6.5-7.5
QRS prolongation = 7.0-8.0
QRS-> sine wave -> VF = >8.5
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66
Q

How is hyperkalemia treated (8)

A

Cardiac membrane stabilization:
Calcium

Redistribution (shift intracellularly)

  • Insulin + D50
  • Hyperventilation
  • HCO3
  • Beta-2 agonist (albuterol)

Elimination:

  • K+ wasting diuretics
  • Kayexalate
  • Dialysis
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67
Q

What are 5 ways potassium is lost via the GI tract

A
  1. Vomiting/diarrhea
  2. NGT suction
  3. Zollinger-Ellison syndrome
  4. Jejunoileal bypass
  5. Kayexalate
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68
Q

What is the most abundant extracellular cation and primary determinant of serum osmolarity

A

Sodium

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69
Q

3 ways that sodium homeostasis maintained

A
  1. Glomerular filtration rate
  2. Renin-angiotensin-aldosterone system
  3. Anti-natriuretic peptides (BNP)
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70
Q

To determine the cause of hypo/hypernatremia, what else must be evaluated

A
  1. Plasma osmolarity

2. ECF volume

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71
Q

Which ion is most important during neural tissue and muscle cell depolarization

A

Sodium

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72
Q

What are 3 causes of hyponatremia related to decreased total body Na+ content

A
  1. Diuretics
  2. Salt-wasting dz
  3. Hypoaldosteronism
73
Q

What are 4 causes of hyponatremia related to normal total Na+ content

A
  1. SIADH
  2. Hypothyroidism
  3. Water intoxication
  4. Perioperative stress
74
Q

What are 2 causes of hyponatremia related to increased total Na+ content

A
  1. CHF

2. Cirrhosis

75
Q

What are 3 causes of hypernatremia related to decreased total Na+ content

A
  1. Osmotic diuresis
  2. N/V
  3. Adrenal insufficiency
76
Q

What are 3 causes of hypernatremia related to normal total Na+ content

A
  1. Diabetes insipidus
  2. Renal failure
  3. Diuretics
77
Q

What are 2 causes of hypernatremia related to increased total Na+ content

A
  1. Hyperaldosteronism

2. Increased Na+ intake (3% Na+)

78
Q
What are signs and symptoms of hyponatremia for the following Na+ concentrations
130-135=
125-129=
115-124=
<115=
A
130-135= no s/sx
125-129= N/V, malaise
115-124= HA, lethargy, altered LOC
<115= Sz, coma, cerebral edema, respiratory arrest
79
Q
What are the signs and symptoms of hypernatremia based on the following serum osmolalities
350-375=
376-400=
401-430=
>431=
A
350-375= HA, agitation, confusion
376-400= Weakness, tremors, ataxia
401-430= Hyperreflexia, muscle twitching
>431= Sz, coma, death
80
Q

What is the goal for correcting sodium imbalance

A

No more than 1-2 mEq/L/hr

81
Q

What can happen is hypo/hypernatremia are corrected too quickly

A

Hyponatremia = fluid shift from ICF to ECF
-Central pontine myelinolysis

Hypernatremia = fluid shift from ECF to ICF
-Cerebral edema

82
Q

What is the distribution of calcium in the plasma

A

50% is ionized
40% bound to albumin
10% bound with an anion

83
Q

What are 3 important functions of calcium

A
  1. Second messenger system
  2. Neurotransmitter release
  3. Muscular contraction
84
Q

Which portion of the cardiac muscle cell action potential is Ca++ responsible for

A

Phase 2

85
Q

Which coagulation factor is Ca++

A

Factor IV

86
Q

How does the acid-base status affect ionized calcium concentration and why

A

Acidosis = increases ionized Ca++ (b/c albumin bind H+ and displaces Ca++)

Alkalosis = decreases ionized Ca++ (b/c albumin bind Ca++ and displaces H+)

87
Q

How does parathyroid hormone affect serum Ca++ concentration

A

PTH raises [Ca++]

88
Q

What hormone reduces serum Ca++ concentration

A

Calcitonin

89
Q

Describe the process by which serum Ca++ levels decrease

A
  1. Thyroid gland releases calcitonin
  2. Osteoclast activity is inhibited
  3. Ca++ reabsorption in kidneys decreases
  4. Ca++ levels in blood decrease
90
Q

Describe the process by which serum Ca++ levels increase

A
  1. Parathyroid gland releases PTH
  2. Osteoclasts release Ca++ from bone
  3. Ca++ is reabsorbed by kidneys
  4. Ca++ absorption in small intestine increases via vitamin D synthesis
  5. Ca++ level increases
91
Q

What are 5 causes of hypocalcemia

A
  1. Hypoparathyroidism
  2. Vitamin D deficiency
  3. Renal osteodystrophy
  4. Pancreatitis
  5. Sepsis
92
Q

What are 5 causes of hypercalcemia

A
  1. Hyperparathyroidism
  2. Cancer
  3. Thyrotoxicosis
  4. Thiazide diuretics
  5. Immobilization
93
Q

What are 6 signs and symptoms of hypocalcemia

A
  1. Muscle cramps
  2. Nerve irritability
  3. Laryngospasm
  4. Mental status change - Sz
  5. Chvostek sign
  6. Trousseau sign
94
Q

What EKG changes are present with hypocalcemia vs hypercalcemia

A

Hypo:
QT interval = LONG

Hyper:
QT interval = SHORT

95
Q

What is the treatment for hypocalcemia

A

Calcium supplement

Vitamin D

96
Q

What is the treatment for hypernatremia

A
0.9% NaCl
Loop diuretic (furosemide)
97
Q

What are 5 signs and symptoms of hypercalcemia

A
  1. Nausea
  2. Abd pain
  3. HTN
  4. Psychosis
  5. Mental status change - Sz
98
Q

Describe the relationship between Mg++ and Ca++ at the neuromuscular junction

A

Mg++ antagonizes Ca++ at the NMJ

99
Q

Normal Mg++ plasma level

A
  1. 7 - 2.4 mg/dL

1. 5 - 3 mEq/L

100
Q

Normal ionized Ca++ level

A
  • *1.16-1.32 mmol/dL**
    2. 2-2.6 mEq/L
    4. 65 - 5.28 mg/dL
101
Q

Normal plasma total Ca++ level

A
  1. 12-2.62 mmol/dL
  2. 5-5.5 mEq/L
    * *8.5-10.5 mg/dL**
102
Q

Where is Mg++ reabsorbed

A

In the renal tubules

103
Q

Mg++ dose for pre-eclampsia

A

4 g load over 10-15 minutes

Then 1 g/hr for 24 hrs

104
Q

How does magnesium infusion affect the neonate

A

Administration for >48 hrs increases the risk of neonatal respiratory depression, hotn, and lethargy d/t Mg++ ability to cross the placenta

105
Q

What is the rational for Mg++ use in multi-modal pain treatment

A

The NMDA receptor antagonism of Mg++ can decrease opioid use

106
Q

What effect can Mg++ have on the airway

A

Can be used to treat acute bronchospasm because it relaxes the airway smooth muscles (antagonizes Ca++)

107
Q

In what instances can Mg++ be administered

A
  1. Pre-eclampsia
  2. Opioid-sparing technique
  3. Acute bronchospasm
  4. Cardiac rhythm disturbances (PVCs or torsades)
108
Q

What are 5 possible causes of hypomagnesemia

A
  1. Poor intake
  2. Alcohol abuse
  3. Diuretics
  4. Critical illness
  5. Associated w/ hypokalemia
109
Q

What are 3 possible causes of hypermagnesemia

A
  1. Excessive administration
  2. Renal failure
  3. Adrenal insufficiency
110
Q

What are 3 symptoms of slightly low magnesium

A
  1. Neuromuscular irritability
  2. Hypokalemia
  3. Hypocalcemia
111
Q

What are 3 symptoms of very low magnesium

A
  1. Tetany
  2. Sz
  3. Dysrhythmias
112
Q

What are 4 symptoms of mildly elevated magnesium

A
  1. Diminished DTRs
  2. Lethargy/drowsiness
  3. flushing
  4. N/V
113
Q

What are 4 symptoms of moderately elevated magnesium

A
  1. Loss of DTRs
  2. HoTN
  3. EKG changes
  4. Somnolence
114
Q

What are 5 symptoms of extremely elevated magnesium

A
  1. Respiratory depression
  2. Complete heart block
  3. Cardiac arrest
  4. Coma
  5. Paralysis
115
Q

How can magnesium levels affect neuromuscular blockade

A

Hypermagnesemia can potentiate succinylcholine and nondepolarizers

116
Q

What does the Henderson-Hasselbalch equation represent

A

That a solutions pH is a function of the ratio of dissociated anions (HCO3-) to non-dissociated acid (CO2)

117
Q

How does the blood aid in acid-base buffering

A
  1. Bicarbonate buffer

2. Hgb (binds to H+)

118
Q

How does the respiratory system act as a buffer during acid-base imbalance

A

By altering ventilation to change PaCO2

119
Q

Describe 3 renal compensatory mechanisms that buffer during acid-base imbalance

A
  1. Reabsorption of filtered HCO3
  2. Removal of titratable acids (non-volatile)
  3. Formation of ammonia
120
Q

How can the intracellular fluid assist with buffering during an acid-base imbalance

A

By exchanging H+ into cells and K+ out of cell

121
Q

Equation to calculate anion gap

A

A Gap = Na - (Cl + HCO3)

122
Q

What are causes of metabolic acidosis with an increased anion gap

A

MUDPILES

  1. Methanol
  2. Uremia
  3. DKA
  4. Paraldehyde
  5. Isoniazid
  6. Lactate (dec DO2, sepsis, cyanide poisoning)
  7. Ethanol, ethylene glycol
  8. Salicylates
123
Q

What are causes of metabolic acidosis with a normal anion gap

A
  1. Hypoaldosteronism
  2. Acetazolamide
  3. Renal tubular acidosis
  4. Diarrhea
  5. Ureterosigmoid fistula
  6. Pancreatic fistula
124
Q

What is the difference between full and partial A-B imbalance compensation

A
Full = pH is restored to normal (but CO2 and HCO3 are abnormal)
Partial = pH is moving towards normal
125
Q

What are 4 cardiac effects of acidosis

A
  1. increased P50
  2. increased SNS tone
  3. Risk of dysrhythmias
  4. Decreased contractility
126
Q

What are 3 cardiac effects of alkalosis

A
  1. Decreased P50
  2. Decreased coronary blood flow
  3. Risk of dysrhythmias
127
Q

What are 2 CNS effects of acidosis

A
  1. Increased cerebral BF

2. Increased ICP

128
Q

What are 2 CNS effects of alkalosis

A
  1. Decreased cerebral BF

2. Decreased ICP

129
Q

What is a pulmonary effect of acidosis

A

Increased PVR (inc CO2)

130
Q

What is a pulmonary effect of alkalosis

A

Decreased PVR (low CO2)

131
Q

How does acidosis affect potassium

A

Can lead to hyperkalemia

132
Q

How does alkalosis affect potassium and calcium

A

Hypokalemia

Low iCalcium

133
Q

What are 3 etiologies for respiratory acidosis

A
  1. Increased CO2 production
  2. Decreased CO2 elimination
  3. Rebreathing
134
Q

At what pH is mechanical ventilation indicated

A

pH < 7.20

135
Q

What are 7 causes of hypercapnia r/t increased CO2 production

A
  1. Sepsis
  2. Overfeeding
  3. Malignant hyperthermia
  4. Intense shivering
  5. Prolonged Sz
  6. Thyroid storm
  7. Burns
136
Q

What are 8 causes of hypercapnia r/t decreased CO2 elimination

A
  1. Airway obstruction
  2. Increased DS
  3. Increased Vd/Vt
  4. ARDS
  5. COPD
  6. Respiratory center depression
  7. Drug OD
  8. Inadequate NMB reversal
137
Q

What are 2 causes of hypercapnia r/t rebreathing

A
  1. Incompetent unidirectional valve

2. Exhausted soda lime

138
Q

How does a change in PaCO2 affect pH in acute respiratory acidosis

A

For every 10 mmHg PaCO2 increase => pH decrease 0.08

139
Q

How does a change in PaCO2 affect pH in chronic respiratory acidosis

A

For every 10 mmHg PaCO2 increase => pH decrease 0.03

140
Q

How does the body compensate for respiratory acidosis

A

The kidneys excrete H+ and conserve HCO3

Full compensation can take days

141
Q

How does respiratory acidosis lead to hypoxemia

A

Increasing alveolar CO2 displaces alveolar O2 leading to arterial hypoxemia

142
Q

How does respiratory acidosis affect P50

A

P50 is increased, causing a right shift in the curve.

This releases more O2 at the tissues

143
Q

How does respiratory acidosis affect cardiac and smooth muscle depression

A

Acidosis affects contractile protein and enzymatic function
Causes:
Myocardial depression
Vasodilation

144
Q

How does respiratory acidosis affect SNS stimulation (5 factors)

A

CO2 activates the SNS and increases catecholamine release

  • Tachycardia (inc O2 consumption and dec delivery)
  • Vasoconstriction (inc O2 consumption)
  • Dysrhythmias
  • Prolong QT
  • Offsets myocardial depression
145
Q

How does respiratory acidosis affect alveolar ventilation

A

It increases

CO2 is a respiratory stimulant and increases minute ventilation

146
Q

How does respiratory acidosis affect K+ concentration

A

Increases by activating the H+/K+ pump***

-Buffers CO2 in exchange for releasing K+ into plasma

147
Q

How does respiratory acidosis affect Ca++ concentration

A

Increases b/c Ca++ and H+ compete for binding on plasma proteins
-H+ will bind with albumin and displace Ca++

148
Q

At what point does CO2 narcosis occur

A

When PaCO2 > 90 mmHg

149
Q

What are 8 causes of respiratory alkalosis

A
  1. Iatrogenic (mechanical ventilation)
  2. Hypoxia (altitude, profound anemia)
  3. Pain
  4. Anxiety
  5. Pregnancy
  6. Drugs (progesterone, salyicilate)
  7. PE
  8. Reduced DS with same alveolar ventilation
150
Q

What are 4 CV effects of respiratory alkalosis

A
  1. Dysrhythmias
  2. Decreased coronary BF
  3. decreased myocardial contractility
  4. Decreased P50 (left shift, less O2 release)
151
Q

What are 4 CNS effects of respiratory alkalosis

A
  1. Inhibition of respiratory drive
  2. Cerebral vasoconstriction
  3. Neuronal irritability
  4. Confusion
152
Q

What are 2 electrolyte effects of respiratory alkalosis

A
  1. Decreased potassium

2. Decreased calcium

153
Q

What are 3 etiologies of metabolic acidosis

A
  1. Accumulation of nonvolatile acids
  2. Loss of HCO3
  3. Large volume resuscitation w/ NaCl
154
Q

What is the difference between anion gap acidosis and non-gap acidosis

A

Gap acidosis = accumulation of acids

Non-gap acidosis = loss of HCO3 or ECF dilution

155
Q

How does the body compensate for metabolic acidosis

A

By eliminating volatile acids (CO2) with increased minute ventilation

156
Q

How is PaCO2 affected by HCO3 levels

A

PaCO2 decreases by 1-1.5 mmHg for every HCO3- decrease of 1 mEq/L

PaCO2 increases by 0.5-1 mmHg for every HCO3 increased of 1 mEq/L

157
Q

In what setting of metabolic acidosis is NaHCO3 indicated

A

Non-gap acidosis

Because most causes are r/t HCO3 loss

158
Q

What causes metabolic alkalosis

A
  1. Increased HCO3
  2. Loss of nonvolatile acids
  3. Increased mineralocorticoid activity
159
Q

What are causes of metabolic alkalosis related to increased HCO3

A
  1. HCO3 administration

2. Massive transfusion

160
Q

How does massive transfusion contribute to metabolic alkalosis

A

The liver converts the preservative from the transfusion into HCO3-

161
Q

What are 4 causes of metabolic alkalosis related to loss of nonvolatile acid

A
  1. Loss of gastric fluid
  2. Loss of acid in urine
  3. Diuretics
  4. ECF depletion
162
Q

What are 2 causes of metabolic alkalosis r/t increased mineralocorticoid activity

A
  1. Cushing’s syndrome

2. Hyperaldosteronism

163
Q

How does the body compensate for metabolic alkalosis

A

The body will retain volatile acid (CO2) by reducing minute ventilation

164
Q

How can metabolic alkalosis d/t increased mineralocorticoid activity be treated

A

Spironolactone

165
Q

What type of acidosis is caused by loss of bicarbonate

A

Non-gap acidosis

166
Q

Why can acetazolamide be used to treat metabolic alkalosis

A

It gets rid of HCO3

167
Q

What are the 4 steps of fluid management

A
  1. Fluid maintenance
  2. Replacing fluid deficit
  3. Replacing third space losses
  4. Replacing blood loss
168
Q

How is fluid maintenance calculated

A

4:2:1 rule
4 mL/kg/hr for first 10-kg
2 mL/kg/hr for second 10-kg
1 mL/kg/hr for each extra kg

OR Body weight in kg + 40 mL

169
Q

How is fluid deficit determined

A

fasting hours x calculated hourly maintenance = estimate fluid deficit

170
Q

How is surgical fluid loss calculated

A

Very minimal = 1-2 mL/kg/hr
-i.e. orofacial surgery

Minimal = 2-4 mL/kg/hr
-i.e. inguinal hernia repair

Moderate = 4-6 mL/kg/hr
-i.e. major non-abd surgery

Major = 6-8 mL/kg/hr
-i.e. major abd surgery

171
Q

How is fluid replacement calculated for blood loss

A
Crystalloid = 3:1 
Colloid = 1:1
172
Q

What are 7 consequences of too little volume resuscitation during surgery

A
  1. Decreased circulatory volume
  2. Decreased O2 delivery
  3. Decreased organ perfusion
  4. Hemoconcentration (increased viscosity)
  5. Myocardial ischemia
  6. Renal impairment
  7. PONV
173
Q

What are 10 consequences of too much volume resuscitation during surgery

A
  1. Excessive circulatory volume
  2. Decreased O2 delivery from congestion
  3. Impaired glycocalyx
  4. Hemodilution
  5. Increased extravascular lung water (impaired gas exchange)
  6. Impaired wound healing
  7. Increased risk of VAP
  8. Abd compartment syndrome
  9. Liver congestion
  10. Impaired gut function (delayed emptying)
174
Q

What is the goal of goal-directed fluid therapy

A

To optimize the pts position on the Starling curve

175
Q

What does the slope of the Starling curve indicate in fluid resuscitation

A

Slope = pre-load dependent

The pt is volume responsive and is a candidate for additional volume

176
Q

What does the plateau of the Starling curve indicate in fluid resuscitation

A

Plateau = optimal balance between volume and myocardial performance
-Preload independence

177
Q

What does the post-plateau down-slope of the starling curve indicate in fluid resuscitation

A

Overshoot = impaired cardiac performance

The pt is at risk for pulmonary edema

178
Q

What are 5 primary objective to enhance postsurgical outcomes in an ERAS program

A
  1. Attenuate physiologic changes that accompany surgical trauma
  2. Minimize impact of fluid shifts
  3. Maximize nutritional impact of healing
  4. Improve postop pain for faster recovery
  5. Improve pt education and compliance
179
Q

What are 5 intraop anesthetic actions used in the ERAS protocol that improve surgical outcomes

A
  1. Short-acting drugs
  2. Goal-directed fluid therapy
  3. Maintain normothermia
  4. PONV prophylaxis
  5. Thoracic epidural when appropriate