Respiratory Failure Flashcards

1
Q

Respiratory failure: physiologic definition is what?

A

Inability of the lungs to meet the metabolic demands of the body.
A failure of tissue oxygenation and/or CO2 homeostasis

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2
Q

A failure of tissue oxygenation and/or CO2 homeostasis simply put is what?

A

cant take in enough O2 or eliminate CO2 fast enough

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3
Q

Components of O2 delivery
O2 Deliver (DO2) =?

A

CO x CaO2

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4
Q

CaO2= ?

A

(1.34 x Hgb x HgbSat%) + (PaO2 x 0.003)

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5
Q

Oxygen Consumption
VO2 =

A

Q x (CaO2 x CvO2)

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6
Q

O2 Extraction Ratio
O2ER =

A

VO2/DO2(normal approx. 25%)

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7
Q

Normal at Sea Level
PIO2 =?
PAO2 =?
PACO2 =?
PAH2O =?
PaVO2 =?
PaO2 =?

A

.21 x (760-47) = 150mmHg
100
40
47
40
95

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8
Q

Types of Respiratory Failure
Hypercapnic RF:

A

PaCO2 > the patients normal value (> 45mmHg in a healthy person)
Pump Failure

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9
Q

Types of Respiratory Failure
Hypoxemic RF:

A

PaO2 < 60 mmHg
Lung Failure

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10
Q

Classes of Respiratory Failure
Type 1 Hypoxemic:
Mechanism =?
Etiology =?
Clinical Setting =?

A

Shunt
Airspace Flooding
Water, Blood or Pus filling the alveoli

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11
Q

Classes of Respiratory Failure
Type 2 Ventilatory:
Mechanism =?
Etiology =?
Clinical Setting =?

A

Decreased Va
Increased Respiratory Load, Decreased ventilatory drive
CNS depression, Bronchospasm, Stiff respiratory system, respiratory muscle failure

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12
Q

Classes of Respiratory Failure
Type 3 Post-op:
Mechanism =?
Etiology =?
Clinical Setting =?

A

Atelectasis
Decreased FRC and increased closing volume
Abdominal surgery, poor inspiratory effort, obesity

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13
Q

Classes of Respiratory Failure
Type 4 Shock:
Mechanism =?
Etiology =?
Clinical Setting =?

A

Decreased CO
Decreased FRC and increased Closing Volume
Sepsis, MI, acute hemorrhage

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14
Q

Important Equations
VE =?

A

VT x RR
VE is min ventilation

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15
Q

VE = alveolar respiration + deadspace

A

VA + VD

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16
Q

PaCO2 =?

A

K x VCO2/VA

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17
Q

PaCO2 ~ ?

A

VCO2/ (1 - VD/VT) x VE

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18
Q

Causes of Hypercapnic Respiratory Failure
CNS

A

Drugs
Disease of the medulla
Idiopathic (Odine’s curse)
Hypothyroidism
Central Sleep Apnea
Metabolic Alkalosis

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19
Q

Causes of Hypercapnic Respiratory Failure
Chest Bellows

A

ALS
Polio
Cord Injury
GBS
MG
Eaton Lambert myasthenic syndrome
phrenic nerve paralysis
NM d/o
tense ascites
post-op states
porphyria
fish toxins
critical illness polyneuropathy
Myopathy
Chest wall abnormalities

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20
Q

Causes Of Hypercapnic Respiratory Failure
Airway Disorders

A

Acute Asthma
COPD

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21
Q

Acute Hypercapnic Respiratory Failure
A decrease in CNS drive leads to?

A

Decrease in RR and VT

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22
Q

Acute Hypercapnic Respiratory Failure
A decrease in RR and VT leads to?

A

Decrease in VE and VA

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23
Q

Acute Hypercapnic Respiratory Failure
A decrease in VE and VA leads to?

A

Rise in PaCO2
Decrease in pH
Decrease in PaO2 (normal or mildly increased A-a gradient)

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24
Q

Decrease in pH
delta pH =?

A

0.008 x delta PaCO2

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25
Q

Hypoventilation
Patm O2 =?
PAO2 =?
PACO2 =?
PAH2O =?
PvO2 =?
PaO2 =?

A

150mmHg
50
80
47
40
45

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26
Q

Acute Hypercapnic Respiratory Failure
Decreased muscle strength leads to?

A

Decrease in VT Increase in RR
Microatelectasis, surfactant inactivation

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27
Q

Acute Hypercapnic Respiratory Failure
Decrease in VT and Increase in RR leads to?

A

Decrease in VE and VA
Rise in PaCO2, Decrease in pH

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28
Q

Acute Hypercapnic Respiratory Failure
Microatelectasis, surfactant inactivation leads to?

A

Decreased compliance
Decreased PaO2 (Increased A-a gradient)

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29
Q

Acute Hypercapnic Respiratory Failure
Asthma/COPD flare
Limited Expiratory flow, bronchospasm and mucus leads to respiratory muscle fatigue how?

A

Increased work of breathing

30
Q

Acute Hypercapnic Respiratory Failure
Asthma/COPD flare
Hyperinflation, flattened diaphragms leads to Respiratory muscle fatigue how?

A

Inefficient breathing

31
Q

Acute Hypercapnic Respiratory Failure
Asthma/COPD flare
Fever leads to respiratory muscle fatigue how?

A

increased ventilatory demand

32
Q

Acute Hypercapnic Respiratory Failure
Asthma/COPD flare
Increased VD/VT leads to Respiratory muscle fatigue how?

A

increased work of breathing

33
Q

Classifications of Hypoxia

A

Hypoxemic
Anemic
Circulatory
Histotoxic

34
Q

Hypoxemic Hypoxia affects what portions of this equation
DO2 =(Hb x 1.34 x SaO2) + (PaO2 x 0.003) x CO

A

SaO2
PaO2

35
Q

Anemic Hypoxia affects what portions of this equation
DO2 = (Hb x 1.34 x SaO2) + (PaO2 x 0.003) x CO

A

Hb

36
Q

Circulatory Hypoxia affects what portions of this equation
DO2 = (Hb x 1.34 x SaO2) + (PaO2 x 0.003) x CO

A

CO

37
Q

Histotoxic Hypoxia affects what portions of this equation
DO2 = (Hb x 1.34 x SaO2) + (PaO2 x 0.003) x CO

A

O2 delivery is normal but metabolic pathways are blocked

38
Q

Hypoxemic Respiratory Failure
PaO2 < ? w/ normal or low ? and normal or high ?

A

60mmHg
PaCO2
pH

39
Q

What is the most common form of respiratory failure?

A

Hypoxemic

40
Q

In hypoxemic respiratory failure what is sever to interfere w/ pulmonary O2 exchange?
What is maintained?

A

lung disease
ventilation

41
Q

What is the physiologic cause of Hypoxemic Respiratory Failure?

A

V/Q Mismatch and shunt

42
Q

Causes of Hypoxemic Respiratory Failure: Pathophysiology (5)

A
  1. Decreased FiO2
  2. Hypoventilation (PaCO2)
  3. V/Q mismatch (eg. COPD)
  4. Diffusion limitation
  5. Intrapulmonary shunt
43
Q

Causes of Hypoxemic Respiratory Failure: Pathophysiology
Hypoventilation and V/Q mismatch also are forms of what?

A

Hypercapnic Respiratory Failure

44
Q

Causes of Hypoxemic Respiratory Failure: Pathophysiology
Intrapulmonary shunt examples?

A

pneumonia
Atelectasis
CHF (high pressure pulmonary edema)
ARDS (low pressure pulmonary edema)

45
Q

Sorting causes of hypoxemic respiratory failure: Value of CXR
Clear Chest x-ray can mean

A

PE
Asthma
COPD
Intracardiac shunt R to L

46
Q

Sorting causes of hypoxemic respiratory failure: Value of CXR
Focal abnormality on Chest x-ray can be?

A

Pneumonia
Atelectasis
Pneumothorax

47
Q

Sorting causes of hypoxemic respiratory failure: Value of CXR
Diffuse Infiltrates on Chest x-ray can be?

A

Cardiogenic pulmonary edema
noncardiogenic pulmonary edema
Interstitial pneumonitis or fibrosis
Infections

48
Q

The Alveolar gas equation
PAO2 =?

A

FiO2 (Patm - PH2O) - PaCO2/R
R = Respiratory quotient = 0.8

49
Q

Mount Everest (8848m)
PIO2 =?
PAO2 =?
PACO2 =?
PAH2O =?
PvO2 =?
PaO2 =?

A

.21 x 253 = 53mmHg
43
7.5
?
?
34

50
Q

Hypoxemia with a Normal A-a gradient means?

A

low FiO2
Hypoventilation

51
Q

Hypoxemia with increased A-a gradient means?

A

V/Q mismatch
Shunt

52
Q

Hypoxemic Respiratory Failure
Normal A-a gradient
Is PaCO2 elevated?
Yes =?
No =?

A

Hypoventilation
High altitude Low inspired PO2

53
Q

Hypoxemic Respiratory Failure
Increased A-a gradient
Does PaO2 improve w/ supplemental O2?
Yes =?
No =?

A

V/Q mismatch
Shunt

54
Q

V/Q mismatch can be from?

A

Airway disease (COPD, asthma, CF, BOS)
Interstitial Lung Disease (IPF, sarcoid, NSIP, DIP)
Alveolar Filling
Pulmonary Vascular Disease (thromboembolism
Fat embolism

55
Q

Shunt can be from?

A

Alveolar filling
Atelectasis
Intrapulmonary vascular shunt (pulmonary AVM)
Intracardiac Shunt (PFO, ASD, VSD)

56
Q

Examples of Alveolar Filling include?

A

Pulmonary edema
LVHF
MV disease
ALI/ARDS of any case
Pneumonia
Trauma
Alveolar Hemorrhage
Alveolar proteinosis
Drugs
TRALI
Acute interstitial pneumonitis
Acute eosinophilic pneumonia
BOOP
Aspiration
Upper airway obstruction
Near drowning

57
Q

Principles of management for respiratory failure
Hypoxemia is?
Primary objective is to?
Secondary objective is to?
Treatment of?
Patient’s CNS and CVS must be?

A

life threatening
reverse and prevent hypoxemia
control PaCO2 and respiratory acidosis
underlying disease
monitored and treated

58
Q

Oxygen Therapy
Titration is based on?

A

SaO2, PaO2 levels and PaCO2

59
Q

Oxygen Therapy
Goal is to?

A

prevent tissue hypoxia

60
Q

Oxygen Therapy
Tiissue hypoxia occurs (normal Hb & CO)
venous PaO2 < ?
arterial PaO2 <?

A

20mmHg or SaO2 < 40%
38mmHg or SaO2 < 70%

61
Q

Oxygen Therapy
Increase arterial PaO2 to > ?

A

PaO2 > 60 mmHg (SaO2 > 90%)
or venous SaO2 > 60%

62
Q

Oxygen Therapy
O2 dose is based on what two factors?

A

flow rate (L/min) or FiO2 (%)

63
Q

Oxygen Therapy
PEEP is utilized to reduce?

A

FiO2

64
Q

100% O2 flow rate (L/min) = what FiO2 (%)
NC
1
2
3
4
5
6

A

24
28
32
36
40
44

65
Q

100% O2 flow rate (L/min) = what FiO2 (%)
Venturi Mask
3
6
9
12
15

A

24
28
35
40
50

66
Q

100% O2 flow rate (L/min) = what FiO2 (%)
NRB
4-10

A

60-80

67
Q

Risks of O2 therapy
O2 toxicity
Very high levels (>100mmHg) can lead to?
Lower levels (FiO2 > 60%) and longer exposure leads to?
PaO2 > 150 can cause?
FiO2 35-40% can be safely tolerated for how long?

A

CNS toxicity and seizures
capillary damage, leak and pulmonary fibrosis
retrolental fibroplasia
indefinitely

68
Q

Risks of O2 therapy
CO2 narcosis
PaCO2 may increased significantly to cause?
PaCO2 increases secondary to combination of what?

A

respiratory acidosis, somnolence and coma
abolition of hypoxic drive to breathe
increased deadspace (worsening of VQ mismatch)

69
Q

Hypercapnic Respiratory Failure Management goals are?

A

Prevent respiratory arrest in patients who are rapidly deteriorating
Restore adequate gas exchange

70
Q

Hypercapnic Respiratory Failure Management
How to restore adequate gas exchange?

A

NPPV
Intubation and mechanical ventilation