BCIT Module 4 Flashcards

1
Q

What are the characteristics of ARDS?

A
  • noncardiogenic pulmonary edema
  • severe hypoxemia (often resistant to O2 therapy)
  • characteristic x ray changes (bilateral opacities)
  • decreased lung compliance
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2
Q

What are examples of direct insults that lead to ARDS?

A

Pneumonia, aspiration, pulmonary contusion

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3
Q

What are examples of indirect insults that may result in ARDS?

A

Sepsis, pancreatitis, nonthoracic trauma

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4
Q

Who are the patients most at risk for developing ARDS?

A

Elderly

Severe acute illness

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5
Q

What is the clinical criteria for diagnosing ARDS?

A
  • within 1 week of known clinical insult or worsening respiratory symptoms
  • bilateral opacities on X-ray not fully explained by effusions, lung collapse or nodules
  • respiratory failure not explained by heart failure or fluid overload
  • P:F < 300
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6
Q

What are the 3 phases of ARDS?

A
  1. Exudative phase
  2. Fibroproliferative phase
  3. Resolution phase
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7
Q

What is the exudative phase of ARDS?

A

First 72 hours, mediators (neutrophils, macrophages, platelets) cause injury to pulmonary capillaries leading to micro thromboemboli, increased pulmonary artery pressures and interstitial edema.

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8
Q

What is the fibroproliferative phase of ARDS?

A

Disordered healing in the lungs characterized by fibrosis of the AC membrane resulting in pulmonary hypertension and hypoxemia

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9
Q

What is the resolution phase of ARDS?

A

Structural and vascular remodeling reestablish AC membrane and intraalveolar fluid is transported out of the alveoli back into the interstitium

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10
Q

What kind of V/Q mismatch is characteristic of ARDS?

A

Shunt

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11
Q

What is shunt?

A

Adequate alveolar perfusion with with inadequate ventilation

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12
Q

What causes hypoxemia in ARDS?

A
  • shunt

- impaired diffusion

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13
Q

What is a normal P:F ratio?

A

> 300

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14
Q

How do you calculate P:F?

A

PaO2 / FiO2

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15
Q

What is the P:F in mild, moderate and severe ARDS?

A
Mild = 200-300 
Moderate = 100-200
Severe = <100
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16
Q

What are typical ABGs in ARDS?

A

Initial = respiratory alkalosis
As fatigue sets in = respiratory acidosis
Progressing = metabolic acidosis (mixed acidosis)

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17
Q

What are the PA catheter changes in ARDS?

A
Increased PADP (8-15 normal)
Normal PCWP (8-12)
PADP > PCWP by >4 (I.e. pulmonary HTN)
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18
Q

What are typical ARDS ventilation strategies?

A
  • low tidal volumes (6 ml/kg, max PPlat of 30)
  • permissive hypercapnia (PaCO2 < 80, pH > 7.2)
  • use of pressure modes to limit barotrauma
  • PEEP to maintain PO2 > 90%
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19
Q

What are fluid administration strategies in ARDS?

A
  • PCWP 5-8
  • fluid restriction
  • diuretics
  • use vasoactive inotropes to support CO instead
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20
Q

What is static compliance?

A

Compliance that is only influenced by compliance of the lung (represented by PPlat in a no-flow state)

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21
Q

What is dynamic compliance?

A

Compliance that is influenced by flow rate, airway diameter and lung compliance (PIP measures dynamic compliance)

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22
Q

What is one of the consequences of increasing a patient’s respiratory rate to compensate for low tidal volumes?

A
  • higher PPlats (less time to reach PIP = increased flow)

- potential for breath stacking with shortened expiratory time

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23
Q

What are the benefits of using pressure mode ventilation over volume in ARDS?

A
  • allow you to control PPlats to prevent barotrauma

- provides laminar flow which helps to open up collapsed airways

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24
Q

What are the benefits of PEEP in ARDS?

A
  • minimizes alveolar collapse
  • reduces WOB (especially at the beginning of inspiration)
  • thins AC membrane
  • lengthens time period during which gas exchange can occur
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25
`What is a biphasic fluid management strategy?
Initial phase with hemodynamic instability from systemic inflammation, give fluids. Once initial stage has passed, restrict fluids
26
What are indications for fluid restriction in ARDS?
- worsening hypoxemia - rising PPlats & PIPs - evidence of increasing pulmonary edema
27
What are indications for fluid replacement in ARDS?
- influence of inflammatory mediators present | - increases in PEEP (I.e. reduction in preload)
28
What are the 2 positioning strategies in the management of ARDS?
Kinetic beds (preferred in hemodynamically unstable patients) Prone positioning (increases perfusion to lung areas that are less likely to be fluid-filled)
29
What are the common pharmacotherapies used in ARDS?
- antibiotic therapy - sedation - pulmonary focused drugs
30
What are the goals of sedation in ARDS?
- optimize ventilation - lower oxygen demand (pain, respiratory muscles) - RASS goal of -3 to -5 - short-acting sedatives preferred with daily sedation interruptions
31
What are the pulmonary-focused drugs used in ARDS?
- broncodilators - mucolytics - surfactant replacement therapy drugs - +/- corticosteroids - pulmonary vasodilating drugs (nitric oxide, prostacyclin)
32
What are the benefits to nitric oxide in ARDS?
- acts on endothelium promoting vasodilation - reduces pulmonary vascular resistance - improves blood flow to ventilated areas of the lungs (because it is inhaled)
33
What are the negatives to giving nitric oxide in ARDS?
- Can cause methemogolbinemia and reduce oxygen carrying capacity - can also cause renal dysfunction
34
What are the extra cellular ions?
Na HCO3 Cl Ca
35
What are the intracellular ions?
K Mg HPO4
36
What is the distribution of ICF to ECF?
1/3 ECF | 2/3 ICF
37
What are the forces of water and electrolyte movement?
``` Osmosis Hydrostatic Pressure Oncotic Pressure Diffusion Filtration Active transport ```
38
What is osmosis?
The movement of water to dilute (equalizes concentrations across membranes)
39
What is hydrostatic pressure?
Force of water/liquid against a membrane (pushes fluid out into interstitium)
40
What is oncotic pressure?
Water drawn to large solutes (pulls fluid in to vascular space)
41
What is diffusion?
Passive movement down concentration gradients
42
What is filtration and what are the factors that influence it?
Renal (glomerular) filtration Increased blood volume = increased GFR Increased cardiac output = increased GFR
43
What is active transport?
The movement of ions up the concentration gradient through the use of ATP
44
What type of fluid is D5W considered?
Hypotonic
45
What is tonicity?
Relative osmotic activity between 2 solutions (hypotonic vs hypertonic)
46
What are the organs/systems that regulate fluids and electrolytes?
``` Kidneys Cardiovascular Lungs Pituitary Adrenal gland Parathyroid ```
47
How do the kidneys regulate fluid and electrolytes?
Filter plasma (GFR) RAAS K+ balance
48
How does the cardiovascular system regulate F and E?
Cardiac output (I.e. through GFR) Baroreceptors (aortic arch) BNP/ANP (excretes sodium)
49
How do the lungs regulate F and E?
Loss of fluid through evaporation (I.e. increased RR)
50
How does the pituitary regulate F and E?
ADH osmoreceptors = increased water retention (responds to concentration) Thirst
51
How does the adrenal gland regulate F and E?
Aldosterone (increased Na, increased H2O, decreased K), responds to concentration AND volume
52
How does the parathyroid hormone regulate F and E?
Calcium balance
53
What are the lab values characteristic of over hydration? | Na, Osm, BUN, HCT
Na normal Osm normal HCT low (diluted) BUN normal-low
54
What are the lab values characteristic of dehydration?
Na normal Osm normal BUN elevated HCT low if hemorrhage, high if other cause
55
What are causes of over hydration?
- excessive fluid administration - heart failure - renal failure - liver disease
56
What are causes of dehydration?
``` Hemorrhage Vomiting Diarrhea GI suctioning Diaphoresis Decreased oral intake ```
57
What are hypertonic problems?
Hypernatremia: water deficit (common) Hypernatremia: overhydration (rare)
58
What are hypotonic problems?
Hyponatremia: water excess (common) Hyponatremia: dehydration (rare)
59
What are the causes of hypernatremia: water deficit?
``` Water deprivation (inability to communicate, immobility) Loss of hypotonic solutes (urine, diarrhea, gastric secretions, furosemide, DI) ```
60
What are the neurohormonal compensatory mechanisms of hypernatremia : water deficit?
Increased ADH Decreased BNP Increased RAAS Decreased water and Na excretion
61
What are the common lab values associated with hypernatremia: water deficit?
Na high Osm high BUN high HCT high
62
What are the treatments for hypernatremia : water deficit?
``` Treat underlying problem (I.e. diarrhea) Hypotonic fluids (water PO, D5W, 1/2 or 1/4 saline) ```
63
What are some causes of hypernatremia : overhydration?
Hypertonic IV solutions, feeding tube solutions Hyperaldosteronism Cushing’s syndrome
64
What are the neurohumoral compensatory mechanisms of hypernatremia : overhydration?
Decreased ADH Increased BNP Decreased RAAS Increased Na and water excretion
65
What are the common lab values associated with hypernatremia : overhydration?
Na increased Osm increased BUN decreased Hct decreased
66
What are some treatments for hypernatremia : overhydration?
Treat underlying problem Diuretics Possibly hypotonic fluids
67
What are some common causes of hyponatremia : water excess?
Polydipsia Water intoxication D5W IV in elderly Flushing tubes/drains with water instead of NS SIADH Renal failure, heart failure, liver failure
68
What are common lab values in hyponatremia : water excess?
Na decreased Osm decreased BUN decreased Hct decreased
69
What are some treatments for hyponatremia : water excess?
``` Treat underlying cause Restrict free water PO Avoid hypotonic IVs Maybe diuretics Maybe hypertonic saline ```
70
What are some causes of hyponatremia : dehydration?
``` Inadequate sodium intake Adrenal insufficiency Sodium loss (excessive diuretics, vomiting, diarrhea, burns) ```
71
What are common lab values seen in hyponatremia : dehydration ?
Na decreased Osm decreased BUN increased Hct increased
72
What are some treatments for hyponatremia : dehydration?
Treat underlying cause Restrict free water PO Avoid hypotonic IVs Maybe hypertonic saline
73
What are the functions of sodium?
Regulates water Affects osmolality Electrical gradient for cellular function
74
What increases sodium absorption?
ADH (indirectly) | RAAS (aldosterone specifically)
75
What causes sodium to be excreted?
BNP | ANP
76
What are causes of hypernatremia?
``` Water deprivation DI HT solutions Hyperaldosterone Cushings Diarrhea Diuretics ```
77
What are symptoms of hypernatremia?
``` Confusion Seizures Coma Thirst Fever Hypereflexia ```
78
What are causes of hyponatremia?
``` Polydipsia SIADH Renal failure Excessive diuretics GI losses Burns ```
79
What are symptoms of hyponatremia?
Confusion Seizures Coma Signs of vascular congestion
80
What are the functions of chloride?
Fluid, electrolyte, H+ balance | CO2 transport
81
What influences chloride absorption?
Follows Na
82
What causes chloride excretion?
Follows Na | Presence of bicarbonate
83
What are causes of hyperchloremia?
Hypernatremia Low bicarbonate Acidosis
84
What are symptoms of hyperchloremia?
Acidosis Tachypnea Decreased CO Decreased LOC
85
What are causes of hypochloremia?
Decreased Na Increased bicarbonate Vomiting (HCl) Diuretics use
86
What are symptoms of hypochloremia?
``` Thirst Dyspnea Cramps, twitching Dysrhythmias Alkalosis ```
87
What are the functions of potassium?
Maintains resting membrane potential Balances H+ ICF osmolality
88
What causes potassium to be absorbed?
Aldosterone
89
What causes potassium to be excreted?
Na/K pump (specifically causes a shift from ECF to ICF)
90
What are causes of hyperkalemia?
Acidosis (H+ into cell for K+) Renal failure Trauma
91
What are symptoms of hyperkalemia?
Muscle weakness Tingling GI cramps Decreased HR
92
What are causes of hypokalemia?
``` Renal losses Intracellular shifts Glucose/insulin GI losses Diuretics ```
93
What are symptoms of hypokalemia?
Muscle weakness (including respiratory muscles) Decreased GI motility (nausea, vomiting) Ventricular irritability
94
What are the functions of calcium?
Cardiac impulse transmission | Clotting
95
What are the absorbing factors of calcium?
Parathyroid hormone
96
What are the excreting factors of calcium?
Calcitonin | Phosphate
97
What are causes of hypercalcemia?
Increased PTH CA with bone mets Renal dysfunction Acidosis (increased [H] kicks Ca off albumin increasing serum levels of Ca)
98
What are symptoms of hypercalcemia?
Weakness Lethargy Shortened QT
99
What are causes of hypocalcemia?
``` Blood transfusion (binds with citrate) Alkalosis (increased Ca binding with albumin) Vitamin D deficiency Thyroid injury Loop diuretics ```
100
What are symptoms of hypocalcemia?
Tentany (signs) Prolonged QT Decreased cardiac contractility
101
What are the functions of phosphate?
Required to produce ATP | Forms 2,3 DPG (right O2D curve shift)
102
What are absorbing factors of phosphate?
GI | Calcium
103
What are excreting factors of phosphate?
Insulin (=shift to ICF) Increased Ca Kidney perfusion
104
What causes hyperphosphatemia?
Massive cellular lysis Renal dysfunction PTH dysfunction
105
What are the symptoms of hyperphosphatemia?
Same as hypocalcemia
106
What are causes of hypophosphatemia?
``` Inadequate intake GI losses Alkalosis (resp) Diuretics Sepsis Burns ```
107
What are symptoms of hypophosphatemia?
Weakness Fatigue Difficult vent weaning (L O2D curve shift due to decrease in 23DPG)
108
What are the functions of magnesium?
DNA formation ATP reactions Helps move Ca into muscle
109
What causes Mg to be absorbed?
Low Ca | Increased albumin
110
What causes Mg to be excreted?
High Ca | Low albumin
111
What are causes of hypermagnesemia?
Renal failure | High intake
112
What are symptoms of hypermagnesemia?
``` Hyperkalemia N/V Weakness Hypotension (vasodilation, flushing) Bradycardia Hypoactive reflexes ```
113
What are the causes of hypomanesemia?
Renal losses (loop diuretics) GI losses Poor diet
114
What are the symptoms of hypomagnesemia?
``` Neurological depression Confusion Tetany Ataxia Anorexia ```
115
What are the management strategies for electrolyte imbalances?
Correct underlying causes Consider influencing factors Alleviate the imbalance
116
What are the factors that influence electrolyte balance?
H+ exchanged for K+ Glucose/insulin take K and phosphate inside the cell with them H+ and Ca compete for binding sites on albumin (bound Ca is inactive) The negative charge of Cl and bicarbonate are used to balance ion excretion in the renal tubules (I.e. excessive bicarbonate excretion is balanced by excessive Cl reabsorbtion)
117
What are the effects of acidosis?
``` Decreased myocardial contractility Arterial vasodilation Pulmonary vasoconstriction (increased dead space) Decrease response to vasoactive drugs (pH<7.2) Increased likelihood of dysrhythmias Decreased LOC R O2D shifts Increased inflammatory response Decreased ATP production Decreased response to insulin ```
118
What are the key functions of the liver?
Metabolism (carbohydrates, proteins, lipids) Storage (fats, vitamins, iron, copper, blood) Filtration (bacteria, antigens, worn RBCs) Detoxification (inactivated hormones, drugs, alcohols, toxins)
119
What are the tests for liver function?
AST (like CK to cardiac) ALT (like troponin to cardiac) Albumin (more for chronic injury) PT (early marker for dysfunction)
120
What is TPN?
Total parenteral nutrition - feeding a person intravenously
121
What are the complications of TPN?
Glucose intolerance | Electrolyte imbalances
122
What is refeeding syndrome?
Feeding after starvation can lead to increased insulin production creating an anabolic environment which leads to cellular shifts of *phosphorus*, potassium and magnesium into cellular space (with ATP)
123
What is the target bG with feeding?
7-9 (both EN and TPN)
124
What is normal RA/CVP?
2-6
125
What are normal PAS/PAD?
20-30/8-15
126
What is normal PCWP?
8-12
127
What is normal CO?
4-8
128
What is normal SVR?
800-1400
129
What is normal SvO2?
60-80