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Mar: Sem 3 - Principles I > Exam 2 Breathing Systems II [6/24/24] > Flashcards

Exam 2 Breathing Systems II [6/24/24] Flashcards

1
Q

What is a Mapleson Circuit used for?

A
  • delivery of oxygen and anesthetic agents
  • removal of carbon dioxide

S52

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2
Q

How many types of Mapleson Circuits are there?

A
  • Six Types (A → F)

S52

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3
Q

What are the components of the Mapleson Circuit?

A
  • Reservoir bag (operator end)
    • not all have this
  • Corrugated tubing
    • not all have this
  • APL valve (variable positioning)
  • Fresh gas inlet (variable positioning)
  • Patient connection/Facemask (Patient end)

S53

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4
Q

What components are absent in all Mapleson Circuit Systems?

A
  • CO2 absorber
  • Unidirectional Valves
  • Separate Inspiratory and Expiratory Limbs

S54

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5
Q

What is another name for the Mapleson Circuit Systems?

A
  • Carbon Dioxide Washout Circuits
  • Flow-controlled Breathing Systems

S54

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6
Q

How does the Mapleson Circuit System prevent rebreathing without a CO2 absorber?

A
  • FGF must be significantly greater than minute ventilation to “washout” the CO2.

S54- lecture

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7
Q

What is another name for Mapleson A?

A
  • Magill’s System

S55

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8
Q
  • Where does fresh gas flow enter in the Mapleson A circuit?
  • Where is the APL valve located in the Mapleson A circuit?
A
  • FGF enters near the reservoir bag (the operator end)
  • APL valve located on patient end

S55

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9
Q
  • Of all the systems, what is Mapleson A best at?
  • What is Mapleson A the worst at?
A
  • Best efficiency of all systems for spontaneous ventilation
  • Worst efficiency of systems for controlled ventilation

S55

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10
Q

How to prevent rebreathing with Mapleson A?

A

FGF must be ≥ minute volume to prevent rebreathing during spontaneous ventilation

S55

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11
Q

In a Mapleson A circuit, rebreathing during controlled ventilation occurs unless minute ventilation is what?

A
  • unless minute ventialtion is very high
  • more than 20 L/min

S55

normal VE=4-6L, so if 20L/min pt is breathing really fast or Vt is significantly increased. PLEASE CONFIRM

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12
Q

Mapleson A Circuit:
What is vented out from the APL valve in spontaneous ventilation during expiration?

A
  • Dead space gas (orange)
  • Alveolar gas (red)

FGF has to be very high to help vent this off.

S56

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13
Q

Mapleson A Circuit:
What is vented out from the APL valve in controlled ventilation during expiration?

A
  • APL valve does not open on expiration.

S56 + lecture

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14
Q

Mapleson A Circuit:
What is vented out from the APL valve in controlled ventilation during inspiration?

A
  • Mostly fresh gas (blue)
  • Some alveolar gas (red)
  • Increase the risk of rebreathing alveolar gas (red)

S56

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15
Q

Where are the APL Valve and Fresh gas inlet located in the Mapleson B Circuit?
Where is the reservoir bag?

A
  • APL and FG inlet located near the patient
  • reservoir bag at the end of the system

S57

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16
Q

Why is the Mapleson B Circuit considered inefficient and obsolete?

A
  • Significant fresh gas is vented through APL during exhalation
  • Blue (FGF)
  • Red (alveolar gas)

S57-58

FGF is right next to the APL, as soon as the pt breaths out & as soon as the FGF comes in, it flows through the APL valve, making this more inefficient.

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17
Q

FGF should be ____ times the minute volume during spontaneous and controlled ventilation to prevent rebreathing in the Mapleson B circuit.

A
  • FGF should be 2x minute volume

S57

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18
Q

Where are the APL Valve and Fresh gas inlet located in the Mapleson C Circuit?

A
  • APL and FGF located near the patient

S59

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19
Q

Mapleson C is identical to Mapleson B except for what specific difference?

A
  • Omission of the corrugated tubing

S59

Looks like an ambu bag

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20
Q

How much FGF is needed for the Mapleson C circuit to prevent rebreathing?

A
  • FGF needs to be 2x minute volume to maintain efficiency

S59

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21
Q

When are Mapleson’s C circuits usually used?

A
  • Emergency resuscitation

S59

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22
Q

What happens with FGF with Mapleson C?

A
  • FGF goes in, not losing as much when its vented to APL valve compared to mapleson B
  • its based on the expiratory pause [is it better or worse]

S60 Lecture

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23
Q

Mapleson D has a 3 way T piece that includes?

A
  • pt connection
  • fresh gas inlet
  • corrugated tuping

S61

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24
Q

Where are the reservoir, APL Valve, and Fresh gas inlet located in the Mapleson D Circuit?

A
  • Reservoir at the end
  • APL valve is located near the reservoir bag
  • FGF inlet is located near the patient

S61

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25
Q

what can be added to mapleson D?

A

PEEP valves may be added

S61

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26
Q

Which system is the most efficent system for controlled ventilation?

A

mapleson D

S61

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27
Q

in Mapleson D FGF is ____x minute ventialtion

A

FGF 2-2.5x minute ventilation

S61

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28
Q

what is bain modification in mapleson D?

A

FGF coaxial inside tubing

S61

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29
Q

Which circuits are known to have “T-modifications” or are known as the “T-group”?

A
  • Mapleson D
  • Mapleson E
  • Mapleson F

S61, 63, 65

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30
Q

What circuit is a modification of Mapleson D?
What is modified?

A
  • Bain Circuit
  • Fresh gas flows through a narrow inner tube (coaxial) nested within the outer corrugated tube.
  • The central fresh gas tubing enters the corrugated hose near the reservoir bag, but the fresh gas actually empties into the circuit at the patient’s end. Exhaled gases pass down the corrugated hose, around the central tubing, and are vented through the pop-off valve near the reservoir bag.
  • Exhaled gases passing down the outer corrugated hose add warmth to the inspired fresh gases by countercurrent heat exchange.

S61- lecture

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31
Q

What is the drawback of the bain circuit?

A
  • disconnection or kinks are not know it bc its inside the corrugated tubing

S61 Lecture

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32
Q

What is happening with mapleson D circuit with spontaneous breathing?

A
  • APL valve is open.

Inspiration:
- FGF come in + alveolar gas [pt gets a both]

Expiration:
- Some alveolar gas gets vented out via pop off valve.
- Dead space gas might or might not get vented out depending on FGF.
- might stay in the reservoir bag & delivered to the pt when squeezed

S62- lecture

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33
Q

what is happening in mapleson D circuit with assisted breathing?

A
  • Partially closed APL
  • If we are increasing the pressure in the system [d/t partially closed APL] when we squeeze on inspiration, the DS gas and alveolar gas can get vented out via the pop off valve
    • Depends on how much FGF goes to the reservoir bag.
    • Since FGF is towards the the pt end, a lot will go towards the pt.

S62

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34
Q

What is another name for Mapleson E?

A
  • Arye’s T-piece

S63

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35
Q

What is missing in the Mapleson E circuit?

A
  • No reservoir bag
  • No APL valve

S63

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36
Q

Where does FGF enter the Mapleson E circuit?

A
  • Near the patient

S63-lecture

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37
Q

What forms the reservoir if there is no Reservoir Bag on the Mapleson E circuit?

A
  • Corrugated Tubing atached to the T-piece forms reservoir

S63

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38
Q

What patient population is the Mapleson E circuit designated for? Why?

A
  • Spontaneous breathing pediatric patients to deliver O2
    • Age: Less than 5 years
    • Weight: Less than 20 kg
  • Has decreased resistance in the system bc of no APL valve which is why its preferred in pediatrics.

S63

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39
Q

How would you increase the pressure of the Mapleson E circuit without an APL valve?

A
  • Occluding the end of the corrugated tubing

S63- lecture

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40
Q

What is happening with mapleson E during spontaneous breathing?

A
  • limb is open to the atmosphere.
  • great for spontaneous breathing.

S64 lecture

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41
Q

what is happening with mapleson E during controlled breathing?

A
  • can only do controlled by pinching of the end of the tubing.
    • will need to pinch, which allows FGF to inflate the lungs, then release the pinch to allow to expire the gases then repeat.
  • Closely watch pressures and for chest rise and fall to prevent increases in pressure.
  • no way to give extra help without timing it appropriately. Bc we cant read it and say how much pressure is being given.

S64-lecture

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42
Q

What is the other name for the Mapleson F circuit?

A
  • The Jackson Rees Modification (of Mapleson E)

S65

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43
Q

What is missing in the Mapleson F circuit?
What is less likely to develope with this circuit?

A
  • No APL Valve
  • Excessive pressure less likely to develope.

S65

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44
Q
  • Where is the FGF inlet on the Mapleson F circuit?
  • Where is the Reservoir Bag on the Mapleson F Circuit?
  • Is there anything special about the Reservoir Bag on the Mapleson F Circuit.
A
  • FGF inlet near patient
  • Reservoir Bag on the operator side
  • Reservoir Bag is open (with a hole)

S65- lecture

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45
Q

How can pressure be generated in the Mapleson F Circuit?

A
  • The reservoir bag hole may be occluded by the operator’s hand to control bag distension and pressure or fitted with a pop-off or PEEP valve for more precise control.

S65- lecture

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46
Q

What does the reservoir bag on the Mapleson F circuit allow?

A
  • Allow for easy tactile and visual monitoring of the patient’s respiratory effort.
  • Can be used to give breaths
  • Can pinch the hole to increase pressure on the breath.

S65- lecture

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47
Q

What is the FGF rate for the Mapleson F circuit?

A
  • 2-2.5 x minute ventilation

S65

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48
Q

What is happening in mapleson F circuit?

A
  • DS gas goes to the reservoir bag and then goes to the atmosphere via the hole
    -Pt is getting mostly alveolar gas and FGF.

S66 Lecture

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49
Q

⭐️Improved rebreathing efficiency is due to what factor?

A
  • Location of the pop-off valve relative to FGF

FGF located near patients will experience less rebreathing.

S67

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50
Q

⭐️Which Mapleson Circuits will experience significant amounts of fresh gas vented through pop-off at end-expiration?

A
  • Mapleson B
  • Mapleson C

S67

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51
Q

⭐️Which systems have FGF that drive exhaled alveolar gas away from pt

A
  • Mapleson D
  • Mapleson E
  • Mapleson F

S67

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52
Q

⭐️Rank the groupings of the Mapleson Circuit in efficiency for spontaneous ventilation from GREATEST to LEAST

A
  • Mapleson A
  • Maplesons D,F,E
  • Maplesons C,B

All Dogs Can Bite

S67

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53
Q

⭐️Rank the groupings of the Mapleson Circuit in efficiency for controlled ventilation from greatest to least.

A
  • Maplesons D,F,E
  • Maplesons B,C
  • Mapleson A

Dog Bites Can Ache

S67

54
Q

What are the advantages of the Mapleson Circuit?

A
  • Simple, inexpensive, and lightweight
  • Changes in FGF composition result in rapid changes in the circuit
  • Low resistance to gas flow
  • No toxic products d/t lack of CO2 absorbent
  • No degradation w/ VAs

S68

55
Q

What are the disadvantages of the Mapleson Circuit?

A
  • Require high FGF (can be wasteful)
  • Conservation of heat and humidity less efficient
  • Scavenging challenging (Except Mapleson D)
    • when APL valve is closer to the pt end, scavenging is challenging bc it’s more wasteful bc a lot of the gas is vented out.
  • Not suitable for patients with MH (May not be possible to increase FGF to remove excess CO2)

S69

56
Q

How does gas travel through the circle system during spontaneous inspiration?

A
  • Reservoir bag deflates. Whatever mixture is the bag [Alveolar gas, SEVO, DES] travels:
    • bypasses pressure guage
    • CO2 absorber
    • Inspiratory valve
      • picking up some FGF
      • valve is open
  • Pt lungs
    • lungs expand
  • Gas sampling port
    • on exhalation, this will give the ETCO2 readout.

S70- lecture

57
Q

What does the circle system allow for?

A
  • Allows for circular and unidirectional flow

S70

58
Q

How does gas travel through the circle system during spontaneous expiration?

A
  • Expiratory valve open, inspiratory valve is closed [no flow here now]
    • gas follows path of least resistance so it goes to the expiratory valve.
  • FGF makes a U-turn/goes backwards since the inspiratory valve is closed and FGF goes to the CO2 absorber
  • Exhaled breath from the patient goes to the expiratory valve then expiratory sensors.
  • Exhaled breath meets up with FGF [thats leaving from CO2 absorber]
  • Reservoir Bag
    • On exhalation, if bag expands too much & pressure increases too much then some will go out to be vented via the APL valve.

S71- lecture

59
Q

During what respiratory cycle phase will the CO2 absorber experience the highest potential of drying out?

A
  • End of expiratory cycle d/t the fresh gas flow traveling retrograde because the inspiratory valve is closed.

S71- lecture

60
Q

For the Circle System, the extent of rebreathing and conservation of exhaled gases depends on _____.

A
  • FGF
  • Higher FGF = less rebreathing but greater amount of gas wasted

S72

61
Q

Rules to prevent rebreathing:

A
  • Unidirectional valve must be located between the pt and the reservoir bag on both the inspiratory and expiratory limbs
  • The fresh gas inflow cannot enter the circuit between the expiratory valve and the pt
  • APL valve cannot be located between the pt and the inspiratory valve (You will lose FGF)

S72

62
Q
  • What kind of circle systems are seen with contemporary/modern systems?
  • Will there be rebreathing that occurs?
A
  • Semi-closed circle system
  • Partial rebreathing occurs, but some waste flow is vented through APL or waste gas valve of the ventilator

S73

63
Q

What is an example of a semi-closed circle system?

A
  • Low-flow anesthesia
  • FGF is less than minute ventilation

S73

64
Q

What percentage of expired gas is rebreathed after CO2 removal during low-flow anesthesia?

A
  • 50%

S73

65
Q
  • What kind of circle systems are considered non-rebreathing?
A
  • Semi-open Circle System
  • Higher FGF with minimal rebreathing and more venting of waste gas

S74

66
Q

What is an example of a semi-open circle system?

A
  • Post-Op and ICU vents
  • Scuba gear
  • Mapleson Circuits

S74

67
Q

In what Circle System will the oxygen inflow rate exactly match the metabolic demand?

A
  • Closed Circle System

S75

68
Q

in a closed system rebreathing is ____ and no ____ is vented

A
  • Rebreathing is complete; no waste gas is vented

S75

69
Q

in what system are volatiles are added to the circuit in liquid form in precise amounts or through the vaporizer?

A

closed circle system

S75

70
Q
  • Example of a closed circle system.
  • why is this system impractical for use, and rarely done?
A
  • ⭐️Low- and minimal-flow anesthesia
  • bc we can now use semi-closed and still use low flow with partial rebreathing with CO2 absorbed.

S75-lecture

71
Q

Advantages of Low-Flow Anesthesia

A
  • Decreased use of volatiles
  • Improved temperature and humidity control
  • Reduced environmental pollution

S76

72
Q

Disadvantages of Low-Flow Anesthesia

A
  • Difficulty rapidly adjusting the anesthetic depth
  • Possibility of accumulating unwanted exhaled gases ( ex: CO, acetone, methane)
  • VA degradation by-products (ex: CO, compound A)

S76

73
Q

Advantages of Circle System

A
  • Low FGF can be used
  • Elimination of CO2
  • Relatively stable inspired gas concentration
  • Conservation of moisture/heat/gases
  • Prevention of OR pollution

S77

74
Q

Disadvantages of Circle System

A
  • Complex design
  • CO or compound A
  • May compromise Vt during controlled ventilation
  • ASA Closed Claims Project (Misconnections/ disconnections)

S77

75
Q

Components of the Self-Inflating Manual Resuscitators (AMBU bags)

A
  • Self-expanding Bag
  • T-shaped non-rebreathing Valve
  • Bag Inlet Valve
  • Pop-off valve
  • Excess oxygen venting valve
  • Oxygen reservoir

S78/79

76
Q

Use of Self-Inflating Manual Resuscitators

A
  • Hand ventilation in the absence of an oxygen or air source
  • Pt transport
  • CPR
  • Emergency back-up

S80

77
Q

What is happening in AMBU bag during inspiration and expiration?

A

S79

78
Q

Which piece of equipment should ALWAYS be available and set up with your anesthesia machine?

A

AMBU bag!

S80- Lecture

79
Q

Hazards of Self-Inflating Manual Resuscitators

A
  • Barotrauma or gastric insufflation
  • Significant variation of tidal volume, PIP, and PEEP
  • Nonrebreathing valves generate resistance

S81

80
Q

What is the purpose of bacteria filters?

A
  • Routine use to prevent contamination or infection by airborne diseases
    • TB, COVID, PUI [Person Under Investigation]
  • Effective at preventing contamination of anesthesia machine from airborne diseases

S82

81
Q

Where are bacteria filters placed on the breathing circuit?

A
  • Placed on the expiratory limb

S82

82
Q
  • There are 2 type of arrangements for bacterial filters. What are they?
  • What are the 2 types of bacterial filters?
A

Arrangment:
1. Small-Pore compact matrix
2. A less dense, Large-Pore size arrangment

Type:
1. Hydrophobic Filter
2. Combination [HMEF]

S83

83
Q

Describe the small-pore compact matrix bacterial filter.
- resistance
- surface area

A
  • High airflow resistance
  • Pleated to create a larger surface area.

S83

84
Q

Describe the larger-pore size arragement bacterial filter.
- resistance
- surface area

A
  • less resistance
  • Smaller surface area

S83

85
Q

The small pore compact matric and large pore arragment bacterial filter have what polarity?

A
  • Permanent electrical polarity.

S83

86
Q

Hydrophobic Bacterial Filters will prevent _____.

A
  • water penetration

S84

87
Q

When the Hydrophobic Bacterial Filters become wet, how does that affect resistance and efficiency?

A
  • Increase resistance
  • Decrease efficiency

S84

88
Q

Where are combination bacterial filters (filter + HME) placed in the breathing circuit?
What does the combination filter cause?

A
  • Placed at the Y-piece

This will cause a barrier to the inspiratory and expiratory limb, increasing resistance. (bc air will not flow well through something wet)

S84

89
Q

Complication of Bacterial Filters.

A
  • Obstruction
    • Sputum, edema fluid, nebulized aerosols, or malpositioning
  • Leakage around the housing of the gas line filter (best to monitor ETCO2 before the filter)

S85

90
Q

When is the placement of the filter on inspiratory limb recommended?

A
  • When machine may be been contaminated by the previous patient

S86

91
Q

When is the placement of the filter on expiratory limb recommended?

A
  • ALL patients
  • pleated mechanical filter preferred

S86

92
Q

When is the placement of the filter by the Y-piece recommended?

A
  • For COVID + or PUI
  • HMEF preferred

S86

93
Q

Humidity

A
  • Amount of water vapor in a gas

S87

94
Q
  • Define absolute humidity
  • What is the absolute humidity in mid trachea?
A
  • Mass of water vapor present in gas in mg H2O/L of gas
  • 34-38 mg of H2O/ L gas in mid trachea

S87

95
Q

Relative Humidity

A
  • Percent saturation
  • the amount of water vapor at a particular temp

S87

96
Q

Water Vapor Pressure

A

The pressure exerted by water vapor in a gas mixture.

S87

97
Q

Maximal contact of inspired gas occurs with the large mucosal surface area in the ____.

A
  • Nasal Cavity

S88

98
Q

Most of the heating and humidification of inspired gas has occurred by ____.
What temperature and humidity?

A
  • Mid-trachea
  • temperature =34°C
  • absolute humidity= 34 to 38 mg/L (95% to 100% relative humidity)

S88

99
Q
  • As gas travels ____, it is heated to ____ ____.
  • Absolute humidity of ____ (100% relative humidity)
  • ____ saturation boundary which is usually right at the ____, but can vary depending on volume, humidity, and temperature.
A
  • distally, body temperature [37℃]
  • 44mg/L
  • isothermic, Carina

S88 and Lecture

100
Q

What are the effects of cold ambient temperatures regarding humidification in the airway?

A
  • Little capacity to hold water vapor
  • Low absolute humidity
  • Upper airway transfers large amounts of heat and moisture

S89

101
Q

What are the effects of warm ambient temperatures regarding humidification in the airway?

A
  • Little heat energy is expended to warm inspired gases

S89

102
Q

Cool inspired gases may trigger ____

A
  • Bronchospasm

Seen more commonly in pts with COPD, asthma, and children with upper respiratory infections/problems

S89

103
Q

Effects of underhumidifaction.

A
  • Damage to the respiratory tract
    • Secretions thicken
    • Ciliary function decreases
    • Surfactant activity is impaired
    • Mucosa susceptible to injury (friable/dried out, bleeds)
  • Body heat loss (longer cases)
  • Tracheal tube obstruction (thicken secretions)
    • Increases resistance and work of breathing from thickened secretions

Cilvia Secretary Serves Manny Heated Olives

S90

very important to conserve heat and humidity to our little patients (neonates, peds)!

104
Q

Effects of overhumidifaction.

A
  • Condensation of water in the airway
    • Reduced mucosal viscosity and risk of water intoxication
    • Inefficient mucociliary transport
    • Airway resistance, risk of pulmonary infection, surfactant dilution, atelectasis, and V/Q mismatch
    • Obstruction to sensors

S91

105
Q

Functions of humidification devices.

A
  • Aim to reproduce more normal physiologic conditions in the lower respiratory tract

S92

106
Q

Types of humidification devices

A
  • Heat and moisture exchanger (HME)
    • Passive
    • can be modified to have a filter
  • Heated humidifiers
    • Active

S92

107
Q

Functions of Heat and Moisture Exchanger (HME)

A
  • Conserves some exhaled heat and water and returns them to the pt
  • Bacterial/viral filtration and prevention of inhalation of small particles (HMEF)
  • Disposable w/ exchange medium enclosed in plastic housing

S93

108
Q

Where is the placement of an HME?

A
  • Placed close to the pt, between Y piece and the proximal end of ETT or LMA

can increase DS

S93

109
Q

What happens to the ETCO2 reading if the sensor is placed:
* AFTER the HME?
* Before the HME?
* Which is more accurate?

A
  • After = Low ETCO2 reading
  • Before = accurate reading

S94

110
Q

What does the HME do to the resistance and dead space in the circuit?

A
  • ↑ resistance
  • ↑ dead space

S94

111
Q

What happens to the efficiency of the HME with a large tidal volume?

A
  • ↓ Efficiency, specifically with hydrophobic models

S94

112
Q

What are the 2 types of HME

A
  1. Hygroscopic HME
  2. Hydrophobic HME

S95

113
Q

What is a Hygroscopic HME?

A
  • Paper or other fiber barrier coated with moisture-retaining chemicals
    • May have some electrostatic properties
  • Absorb water in exhalation and release it in inspiration

S95

114
Q

What is Hygroscopic HME most efficient at?

A
  • Most efficient at retaining heat and moisture

S95

115
Q

What is the drawback of Hygroscopic HME?

A
  • Prone to becoming saturated
    • Increased inspiratory/expiratory resistance
    • Reduced heat and moisture retention efficiency

S95

116
Q

What is a Hydrophobic HME?

What is a Hydrophobic HME efficient at?

A
  • Pleated (Lg SA) hydrophobic membrane with small pores
  • More efficient filters of pathogens

S95

117
Q

Devices used to increase the humidity in O2 supplied to pts

A
  • Humidifiers
  • May be heated or unheated.

S96

118
Q

Who will benefit from humidifiers?

A
  • Neonates
  • Pts with respiratory secretions
  • Hypothermic pts

S96

119
Q

What are the different ways a humidifier can pass a stream of gas?

A
  • Bubble or cascade
  • Pass-over
  • Counter-flow
  • Inline

S96

120
Q

Where are the humidifiers placed in the breathing circuit? Where should they NOT be placed?

A
  • Placed in the inspiratory limb downstream of the unidirectional valve
  • Heated humidifiers should not be placed in the expiratory limb

S96

121
Q

Describe the Bubble/Cascade humidifier.

A
  • Active humidifier that work by passing the fresh gas flow down a tube through a water reservoir causing the gas to “bubble.”
  • Water vapor is absorbed as the bubbles pass through the reservoir

S96- lecture

122
Q

Describe the Passover humidifier.

What are the two varients of this humidifier?

A
  • Passover humidifiers work by passing gas over a heated water reservoir.
  • There are two variants: one that utilizes a wick and one that utilizes a hydrophobic membrane.

S96, lecture

123
Q

Describe the Counter-flow humidifier.

A
  • Water is heated outside the vaporizer in counter-flow humidifiers.
  • After the water is heated, it is pumped to the top of the humidifier, entering small diameter pores and running down a large surface area.
  • Gas, flowing in the opposite direction, is warmed and humidified to body temperature.

S96, lecture

124
Q

Describe the inline vaporizer humidifier.

A
  • utilize a plastic capsule that injects water vapor and heat directly into the inspiratory limb of the ventilator circuit just before the patient’s y-piece.

S96, lecture

125
Q

Most unheated humidifiers are disposable that use the bubble-through humidifier that increases the humidity in oxygen supplied to patients via a face mask or nasal cannula. They cannot deliver more than about ____ mg H2O/L.

A
  • 9 mg H2O/L

S96

126
Q

Condensation has what effect on tidal volume?

A
  • Decrease Vt

S96

127
Q

Consideration for water traps in humidifiers.

A
  • Change frequently to decrease the risk of contamination and infection

S96

128
Q

Advantages of Humidifiers

A
  • Can deliver saturated gas at body temp or higher
  • More effective than HME in longer cases in preventing hypothermia

S98

129
Q

Disadvantages of Humidifiers

A
  • Bulky
  • Potential electrical malfunction and/or thermal injury
  • Contamination, and cleaning issues
  • Higher cost than HME
  • Water aspiration risk

Bulky Humidifiers Potentially Contaminate Water

S98

130
Q

What 3 things can change where the isothermic saturation boundary is?

A
  • Volume of gas inhaled
  • humidity
  • temperature

Mar: Sem 3 - Principles I (29 decks)

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