Breathing Systems Pt. 2 (Exam II) Flashcards

1
Q

What components are missing from a Mapleson circuit?

A
  • CO₂ absorber
  • Unidirectional valve
  • Separate Ins & Exp limbs
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2
Q

Which system has the best efficiency for spontaneous ventilation?

A

Mapleson A (Magill’s System)

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3
Q

Which system has the worst efficiency for controlled ventilation?

A

Mapleson A (Magill’s System)

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4
Q

Rebreathing with a Mapleson A during a controlled ventilation situation occurs unless what?

A

Unless minute ventilation if very higher (>20 L/min)

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5
Q

How is rebreathing prevented during spontaneous ventilation with a Magill’s system?

A

FGF must be greater than (or equal to) minute volume.

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6
Q

FGF should be 2x minute volume during spontaneous and controlled ventilation to prevent rebreathing in a _________ system.

A

Mapleson B

System is obsolete

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7
Q

How does a Mapleson C circuit differ from a Mapleson B?

A

Mapleson C excludes corrugated tubing found on Mapleson B.

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8
Q

What circuit is used for emergency resuscitation?

A

Mapleson C

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9
Q

What FGF characterized a Mapleson C circuit?

A

2x minute volume.

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10
Q

What breathing circuit is most efficient for controlled ventilation?

A

Mapleson D

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11
Q

What is the Bain modification?
What breathing circuit is it used on?

A

Inspiratory gas targeted through an inner tube. Expiratory gasses exhaled into the outer corrugated tubing.

Used on a Mapleson D

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12
Q

What FGF is used with a Mapleson D system?

A

2 - 2.5 x minute ventilation

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13
Q

Which circuit has no reservoir bag or APL valve?

No capability to ventilate the patient manually

A

Mapleson E

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14
Q

Which circuit is used in spontaneously breathing patients to deliver O₂ ?

A

Mapleson E

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15
Q

What is another name for a Mapleson E circuit?

A

Ayre’s T-Piece

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16
Q

A Jackson Rees is a modified ___________ circuit, where a reservoir bag is added to the circuit.

A

Mapleson E

Mapleson E + Jackson Rees = Mapleson F

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17
Q

How is excessive pressure prevented with a Mapleson F circuit?

A

No APL valve present

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18
Q

List all the Mapleson Circuits in terms of most efficient to least efficient for spontaneous ventilation.

A

A > DFE > CB

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19
Q

List all the Mapleson Circuits in terms of most efficient to least efficient for controlled ventilation.

A

DFE > CB > A

21
Q

What are the disadvantages of Mapleson circuits?

A
  • Require high FGF
  • Can’t conserve heat & humidity
  • Scavenging difficult (except D)
  • Not suitable for MH patients (cant increase FGF to remove CO₂)
22
Q

Extent of rebreathing and conservation of exhaled gasses in a circle system depends on _____.

A

FGF

23
Q

In a circle system, higher FGF = less _________ and more ______ ____.

A

rebreathing; waste gas

24
Q

How is rebreathing prevented in a circle system?

A
  • Unidirectional valves located between patient & reservoir bag
  • FGF cannot enter circuit between exp valve & patient
  • APL valve cannot be located between patient & inspiratory valve.
25
Q

What characteristics define a semi-closed circle system?

A
  • Low-flow anesthesia
  • FGF < minute ventilation
  • 50% of expired gas is rebreathed after CO₂ removal
26
Q

In what patients would a semi-open circle system be used?
Why?

A
  • post-op & ICU vents, scuba
  • Higher FGF w/ minimal rebreathing and more venting of waste gasses.
27
Q

What are the characteristics of a closed circle system?

A
  • Complete rebreathing
  • No waste gas vented
  • O₂ matches metabolic demand
  • Minimal flow anesthesia
  • VAAs are added in precise amounts
28
Q

What are the advantages of Low-flow anesthesia?

A
  • Decreased VAA usage
  • Better temp & humidity control
  • Reduced environmental pollution
29
Q

What are the disadvantages of low-flow anesthesia?

A
  • Difficulty adjusting depth quickly
  • Possible accumulation of gasses (CO, acetone, methane, etc)
  • VAA degradation products
30
Q

What are the advantages of a circle system?

A
  • Low FGF can be used
  • CO₂ elimination
  • Conserves heat/moisture/etc.
  • OR pollution prevention
  • stable inspired gas concentration
31
Q

What are the disadvantages to a circle system?

A
  • Complex design
  • CO or compound A
  • Compromised VT during controlled ventilation
32
Q

What are the use cases for self-inflating manual resuscitators?

A
  • Pt transport
  • CPR
  • Emergency backup
  • hand ventilation in absence of O₂ or medical air
33
Q

What are hazards associated with self-inflating manual resuscitators?

A
  • Barotrauma
  • Gastric insufflation
  • Large variation in VT, PIP, and PEEP
  • non-rebreathing valves generate resistance
34
Q

Where are bacterial filters placed on the breathing system?

A

Expiratory limb

35
Q

What are the two types of bacterial filters?

A
  • Small pore (↑ resistance, pleated for ↑ surface area)
  • Large pore ( ↓ resistance, smaller surface area)
36
Q

Where would a combination bacterial filter (filter + HME) be placed?

A

At the Y-piece (inspiratory and expiratory barrier)

37
Q

What are some of the complications of bacterial filters?

A
  • Obstruction (sputum, edema fluid, etc)
  • Leakage
38
Q

At what point in the airway is heating and humidification of air complete?

A

Mid-Trachea

39
Q

Cool inspired gas may trigger ________.

A

Bronchospasm

40
Q

Absolute humidity occurs at _____ mg/L (100% relative humidity).

A

44 mg/L

41
Q

What can occur with underhumidification of air?

A
  • Resp Tract damage
  • Body heat loss
  • Tracheal tube obstruction (thickened secretions)
42
Q

What are HMEs?
Where are they placed?

A
  • Heat and Moisture Exchanger
  • Placed between Y-piece and proximal end of ETT
43
Q

What are some disadvantages with use of an HME?

A
  • Lower EtCO₂ reading
  • ↑ resistance & circuit dead space
  • Reduced efficiency w/ large VT
44
Q

What are the advantages of active humidifiers?

A
  • Can deliver gas at body temp or even higher
  • More effective than HME’s
45
Q

What are the disadvantages of active humidifiers?

A
  • Bulky
  • Contamination (hard to clean)
  • Expensive (compared to HME)
  • Electrical problems/ thermal injury potential
  • Water aspiration risk
46
Q

Extent of rebreathing and conservation of exhaled gasses in a circle system depends on _____.

A

FGF

47
Q

What are the advantages of Mapleson Circuits?

A
  • Simple, inexpensive, lightweight
  • Low resistance to gas flow
  • No toxic products d/t CO₂ absorbent
  • No degradation of VAA’s