EQUIPMENT-Resp monitors & equipment Flashcards

1
Q

Define resistance

A

The force that acts opposite to the relative motion of an object (or flow)

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2
Q

Define pulmonary compliance

A

The ability of the lungs to stretch and expand.

The change in volume fore a given change in pressure

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3
Q

What are 2 types of pulmonary compliance

A
  1. Static compliance

2. Dynamic compliance

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4
Q

What does static compliance assess

A

Assesses the pressure required to keep the lung inflated inflated to a given volume when there is no air movement
Compliance when there is no airflow to keep lungs open

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5
Q

What does dynamic compliance assess

A

Assesses the pressure required to inflate the lung to a given volume when there’s airflow
Compliance of the lung/chest wall during air movement

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6
Q

What 2 factors impact dynamic compliance

A
  1. Airway resistance

2. Tendency of the lungs/chest to collapse

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7
Q

What is PIP

A

Peak inspiratory pressure

Maximum pressure in the patients airway during inspiration

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8
Q

What is plateau pressure

A

The pressure in the small airways and alveoli after the target Vt is achieved

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9
Q

What do alterations in PIP and plateau pressure indicate

A

Pressures in resistance or compliance

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10
Q

How is increased resistance manifested with PIP and plateau pressure
Examples of increased resistance

A
PIP = increased
PP = normal

Ex: kinked tubing, bronchospasm

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11
Q

How is decreased pulmonary compliance displayed with PIP and plateau pressure

Examples

A

PIP = increased
Plateau pressure = increased

Ex: Endobronchial intubation, pulmonary edema

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12
Q

What are 5 factors that influence pulmonary compliance

A
  1. Muscle tone
  2. Degree of lung inflation
  3. Alveolar surface tension
  4. Amount of interstitial lung water
  5. Pulmonary fibrosis
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13
Q

What is the equation for dynamic compliance

A

Dynamic compliance = tidal volume/(PIP - PEEP)

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14
Q

What factor of pulmonary mechanics does plateau pressure reflect

A

Elastic recoil of the lungs and thorax during inspiratory pause

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15
Q

At what plateau pressure does barotrauma risk increase

A

P>35 cmH2O

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16
Q

What are 4 complications of elevated plateau pressure

A
  1. Ventilator-associated lung injury
  2. PTX
  3. Pneumomediastinum
  4. SQ emphysema
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17
Q

What measures can be taken to decrease the risk of barotrauma r/t increased plateau pressure

A
  1. Reduce Vt
  2. Reduce inspiratory flow (I:E ratio)
  3. PEEP
  4. Adequate sedation
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18
Q

Statis compliance equation

A

Static compliance = Tidal volume/(plateau pressure - PEEP)

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19
Q

What is the normal range for static compliance in adults and children

A
Adults = 35 - 100 mL/cmH2O
Children = > 15 mL/cmH2O
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20
Q

What does the PIP/PP waveform look like when resistance is increased

Examples

A
PIP = increased
PP = no change

Ex: kinked ett, bronchospasm, bronchial secretions, foreign body aspiration, airway compression

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21
Q
What does the PIP/PP waveform look like in the following situations
Kinked ETT
Bronchospasm
Bronchial secretions
Foreign body aspiration
Airway compression
A
PIP = increased 
PP = no change
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22
Q

What does the PIP/PP waveform look like when compliance is decreased

Examples

A
PIP = increased
PP = increased

Ex: Endobronchial intubation, pulmonary edema, effusion, PTX, atelectasis, insufflation, ascites, T-burg, inadequate relaxation

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23
Q
What does the PIP/PP waveform look like in the following situations:
Endobronchial intubation
PTX
Pulm edema
Atelectasis
Insufflation
T-burg
A

Both PIP and PP increased

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24
Q

What 3 physiologic processes are assessed by EtCO2

A

Metabolism
Circulation
Ventilation

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25
Q

What does an increased alpha angle on the EtCO2 suggest

A

Expiratory airway obstruction

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26
Q

What does an increased beta angle on the EtCO2 suggest

A

Rebreathing d/t faulty inspiratory valve

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27
Q

What is measured during phase I of the EtCO2 waveform

A

Exhalation of anatomic dead space

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28
Q

What is measured during phase II of the EtCO2 waveform

A

Exhalation of anatomic dead space + alveolar gas

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29
Q

What is measured during phase III of the EtCO2 waveform

A

Exhalation of alveolar gas

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30
Q

What is measured during phase IV of the EtCO2 waveform

A

Inspiration of fresh gas, No CO2 present

31
Q

What are examples of an increased alpha angle on EtCO2

A
  1. COPD
  2. Bronchospasm
  3. Kinked ETT

This indicates obstruciton

32
Q

Why is the anatomic dead space portion of the EtCO2 curve flat

A

Because no gas is exchange in dead space, so CO2 isn’t present

33
Q

What are the benefits of in-line EtCO2 monitoring

A
  1. Faster response time, no delay in reading

2. Doesn’t require water trap or pump

34
Q

What are disadvantages of in-line CO2 monitoring

A
  1. Attached to ETT

2. Increases apparatus dead space

35
Q

Where is in-line vs sidestream EtCO2 located in the breathing system

A
In-line = connected to ETT
Sidestream = outside of airway
36
Q

What are the advantages of sidestream CO2 monitor

A

Doesn’t add apparatus dead space because it is located outside of the airway

37
Q

What are 2 disadvantages of the sidestream CO2 monitor

A
  1. Delay in reading EtCO2

2. Requires a water trap to prevent device contamination

38
Q

What does airflow obstruction look like on EtCO2 waveform

A

Prolonged upstroke

Increased alpha angle

39
Q

How are cardiac oscillations displayed on EtCO2

A

The end of the EtCO2 waveform oscillates in-time with the HR

40
Q

What does curare cleft look like on EtCO2 waveform

What does this indicate

A

A notch just before the beta angle

Indicates:

  1. spontaneous breaths during mechanical ventilation
  2. Inadequate reversal during spontaneous respirations
41
Q

What does a low EtCO2 waveform indicate

A
  1. Hyperventilation
  2. Decreased CO2 production
  3. Increased alveolar dead space (HoTN, PE)
42
Q

What can a high EtCO2 waveform indicate

A
  1. Increased CO2 production (MH, sepsis, hyperthyroid storm)

2. Decreased alveolar ventilation (hypoventilation)

43
Q

What does an increased CO2 baseline on EtCO2 waveform indicate (5 examples)

A
  1. Rebreathing
  2. Exhausted CO2 absorbent
  3. Incompetent expiratory valve
  4. Hole of inner tube in Bain system
  5. Inadequate FGF
44
Q

How does a leak in the sample line appear on the EtCO2 waveform

A

Beginning of plateau is low because of dilute alveolar gas with atm air

Once inspiration occurs, CO2-rich gas is pushed through the sample line resulting in a peak at the end of the plateau

45
Q

Describe the biphasic expiratory plateau
Causes
Morphology of waveform

A

Causes = single-lung transplant

Morphology = Each lung has a different time constant so there are 2 peaks.

  • First peak = alveolar gas from transplanted lung with normal time constant
  • Second peak = alveolar gas from dzd lung. Air trapping results in longer time constant
46
Q

What conditions result in biphasic expiratory EtCO2 plateaus

A

Single-lung transplant

Severe kyphoscoliosis

47
Q

What are 3 factors that can increase CO2 production and EtCO2

A
  1. MH
  2. Thyrotoxicosis
  3. Tourniquet removal
48
Q

What are 3 factors that decrease alveolar ventilation and increase EtCO2

A
  1. CNS depressants
  2. COPD
  3. Residual NMB
49
Q

What are 3 equipment malfunction scenarios that increase EtCO2

A
  1. CO2 absorbent exhaustion
  2. Unidirectional valve malfunction (open)
  3. Increased apparatus dead space
50
Q

What are 4 factors that can decrease CO2 production and EtCO2

A
  1. Hypothermia
  2. Decreased CO
  3. V/Q mismatch
  4. PE
51
Q

What are 2 factors that increase alveolar ventilation and decrease EtCO2

A
  1. Hyperventilation

2. Inadequate anesthesia

52
Q

What are 3 equipment related issues that decrease EtCO2

A
  1. Esophageal intubation
  2. Poor LMA seal
  3. Sample line leak
53
Q

What 4 factors are required for EtCO2 detection

A
  1. CO2 production via metabolism
  2. Adequate pulmonary BF for CO2 delivery
  3. Adequate ventilation to transport CO2 to circuit
  4. Intact sample line
54
Q

What are the 4 categories that contribute to EtCO2 changes

A
  1. CO2 production (metabolism)
  2. Pulmonary perfusion
  3. Adequate ventilation
  4. Equipment
55
Q

On what law is the pulse oximeter based

A

Beer-Lamber Law

56
Q

What is the Beer-Lambert Law

A

Relates the intensity of light transmitted through a solution (blood) and the concentration of the solute (hgb) within the solution

57
Q

What two wavelengths of light are measured

Where are they preferentially absorbed

A
Red light (660 nm) = deoxyhgb
Near-infrared (940 nm) = oxyhgb
58
Q

Which pulse-ox monitoring sites are more responsive

A

More central sites (forehead, ear) vs peripheral (toe)

59
Q

How does the peak and trough of the pulse-ox waveform compare

A

Peak = greater amount of arterial blood in sample

Trough = greater amount of venous blood in sample

60
Q

What 2 physiologic factors affect pulse-ox monitoring sites

A
  1. Vasoconstricitve effects of SNS stimulation

2. Hypothermia

61
Q

What is the estimated PaO2 corresponding to the following SpO2 %
90% =
80% =
70% =

A
90% = PaO2 60 mmHg
80% = PaO2 50 mmHg
70% = PaO2 40 mmHg
62
Q

What is the estimated PaO2 when SpO2 is 100%

A

At least 100 mmHg, but unable to extrapolate a PaO2 without drawing and ABG

63
Q

What are 5 methods of improving SpO2 signal

A
  1. Place a digital block
  2. Warm the extremity
  3. Protect the extremity from ambient light
  4. Apply vasodilating cream
  5. Administer an arterial vasodilator
64
Q

What 4 factors does a pulse-ox noninvasively monitor

A
  1. Hgb saturation
  2. HR
  3. Fluid responsiveness (pulse pressure variation)
  4. Perfusion
65
Q

What are 3 factors that a pulse-ox does NOT monitor

A
  1. Anemia
  2. Ventilation
  3. Bronchial intubation
66
Q

Why is the pulse-ox not a good measure of ventilation

A

Pt may have a normal SpO2, especially w/ supplemental O2, but it does not indicate CO2 exchange and can become hypercarbic in the presence of 100% SpO2

67
Q

What wavelength of light does methemoglobin absorb

A

660 nm and 940 nm equally

68
Q

What will SpO2 read in the presence of MetHgb

Does this over or underestimate SpO2

A

85%
Underestimate if O2 >85%
Overestimates if O2 <85%

69
Q

What wavelength of light does carboxyhgb absorb

A

660 nm to the same degree as Oxyhgb

70
Q

How does carboxyhgb affect pulse oximetry monitoring

A

The CarboxyHgb + OxyHgb are both read and OVER estimate SpO2

71
Q

What are 6 causes of inaccurate SpO2 reading

A
  1. Decreased perfusion
  2. Altered optical characteristics (nail polish)
  3. Non-pulsatile flow
  4. Motion
  5. Skin color
  6. Electrocautery
72
Q

How does nail polish alter SpO2 quality

How can it be fixed

A

Black, blue, and green polishes can cause inaccurate reading

Fix = place probe sideways on the finger below the nail

73
Q

How do jaundice, acrylic fingernails, polycythemia, and hgb F affect the accuracy of SpO2 monitoring

A

They do NOT affect the reliability of the pulse oximeter

74
Q

How are respiratory gases analyzed

A

Infrared absorption spectophotometry