E2 - Breathing Systems II Flashcards
What is a Mapleson Circuit used for?
A. used for the delivery of oxygen and anesthetic agents
B. used for the delivery of anesthetic agents only
C. used for the delivery of oxygen and anesthetic agents and the removal of CO2
D. used for the removal of CO2 only
C. used for the delivery of oxygen and anesthetic agents and the removal of carbon dioxide
What are the 5 components of a Mapleson Circuit?
PRCAF
- Patient connection/Facemask
- Reservoir bag
- Corrugated tubing
- APL valve
- Fresh gas inlet
What 3 components are absent in all Mapleson Circuit Systems?
CUS
- CO2 absorber
- Unidirectional Valves
- Limbs (seperate inspiratory and expiratory limbs)
What are 2 other names for the Mapleson Circuit Systems?
A. CO2 washout circuits
B. Flow-controlled breathing systems
C. CO2 controlled system
D. Corrugated Circuits
A. Carbon Dioxide Washout Circuits
B. Flow-controlled Breathing Systems
How does the Mapleson Circuit System prevent rebreathing without a CO2 absorber?
A. The pop off valve allows it to escape
B. FGF must be lower than minute ventilation
C. The CO2 goes into the reservoir bag
D. FGF must be significantly greater than minute ventilation.
D. FGF must be significantly greater than minute ventilation to “washout” the CO2.
What is another name for Mapleson A?
A. Adjustable system
B. Magill’s system
C. Bain system
D. Main system
B. Magill’s System
For MAPLESON A circuit
Where does fresh gas flow enter? Where is the APL valve located?
A. both on patient’s end
B. operator end; patient end
C. both on operator’s end
D. patient end; operator end
B. FGF enters from the operator end, near the reservoir bag; APL valve located on patient end
What is Mapleson A best at compared to the other systems?
What is Mapleson A the worst at?
- Best efficiency of all systems for spontaneous ventilation
- Worst @ controlled ventilation (b/c FGF needs to be 20 L/min or higher!)
For MAPLESON A Circuit:
What is vented out from the APL valve in spontaneous ventilation during expiration?
2 gases
- Dead space gas (yellow)
- Alveolar gas (red)
For MAPLESON A Circuit:
What is vented out from the APL valve in controlled ventilation during expiration?
A. dead space gas
B. both dead space and alveolar gas
C. alveolar gas
D. APL valve does not open
D. APL valve does not open
For MAPLESON A Circuit:
What is vented out from the APL valve in controlled ventilation during inspiration?
- Mostly fresh gas (blue)
- Some alveolar gas (red)
- Increase the risk of rebreathing alveolar gas (red)
that’s why this is the worst one for controlled ventilation!
For MAPLESON B Circuit:
Where are the APL Valve and Fresh gas inlet located?
A. near the patient
B. near the operator
C. near the reservoir bag
D. on seperate ends
A. APL and FG inlet are both located near the patient!
For MAPLESON B Circuit:
Why is the Mapleson B Circuit considered inefficient and obsolete?
- Much of fresh gas is vented through APL during exhalation
- Blue (FGF)
- Red (alveolar gas)
For MAPLESON B Circuit:
FGF should be ____ times the minute volume during spontaneous and controlled ventilation to prevent rebreathing in Mapleson B.
A. 3x
B. 2x
C. 20x
D. 10x
B. FGF should be 2x minute ventilation
for mapleson B circuit
For MAPLESON C Circuit:
Where are the APL Valve and Fresh gas inlet located?
A. near the patient
B. near the operator
C. near the reservoir bag
D. on seperate ends
A. APL and FGF both located near the patient
identical to mapleson B in this sense
Mapleson C is identical to Mapleson B except for what specific difference?
A. No reservoir bag
B. No APL valve
C. No corrugated tubing
D. No CO2 absorber
C. NO corrugated tubing
How much FGF is needed for the Mapleson C circuit to prevent rebreathing?
- FGF needs to be 2x minute volume to maintain efficiency
similar to mapleson B also
What are Mapleson C circuits used for?
- Emergency resuscitation
Emergen-C
Where are the APL Valve and Fresh gas inlet located in the Mapleson D Circuit?
A. both near reservoir bag at the end
B. APL near reservoir bag at the end + FGF inlet near the patient
C. APL near patient + FGF inlet near reservoir bag
D. both near patient
B. APL valve is located near the reservoir bag at the end of circuit + FGF inlet is near the patient
Which circuits are known to have “T-modifications” or are known as the “T-group”?
- Mapleson D
- Mapleson E
- Mapleson F
T-piece = DEF
Which circuit is the MOST efficient for controlled ventilation?
- Mapleson D
What kind of valve can be added to Mapleson D circuits?
A. another APL valve
B. expiratory valve
C. PEEP valve
D. inspiratory valve
C. PEEP Valve
FGF rate should be _______ times minute ventilation in Mapleson D circuits.
- 2 to 2.5 times
What is a Bain modification of Mapleson D?
- FGF coaxial (narrow inner tube) inside corrugated tube.
What is another name for Mapleson E?
A. Arye’s T-piece
B. Bain T-Piece
C. Emergency T-Piece
D. APL T-Piece
A. Arye’s T-piece
What is missing in the Mapleson E circuit that the other circuits have? Select 2.
A. Reservoir bag
B. CO2 absorber
C. APL valve
D. HME
E. humidifier
no reservoir bag (A) + No APL valve (C) in mapleson E circuits!
used in spontaneously breathing pts to deliver O2; mainly pediatrics!!
For MAPLESON E Circuit:
Where does FGF enter?
- Near the patient
What forms the reservoir in the Mapleson E circuit if there is no Reservoir Bag?
- Corrugated Tubing
What patient population is the Mapleson E circuit designated for? select 2
A. controlled ventilation
B. only adults
C. spontaneous breathing
D. pediatric patients
E. this one is obselete; won’t use it
C. Spontaneous breathing
D. pediatric patients
since there’s much lower resistance w this circuit
Age: Less than 5 years / Weight: Less than 20 kg
What is the other name for the Mapleson F circuit?
A. Ayre’s T piece
B. Circle system
C. Jackson Rees Circuit
D. Bain Circuit
C. Jackson Rees Circuit
What is the Jackson Rees modification of Mapleson E?
A. added APL
B. added reservoir bag
C. added FGF coaxial tubing
D. added co2 absorber
B. Reservoir bag is added!
still no APL tho similar to mapleson E
For MAPLESON F circuit:
Where is the FGF inlet?
Where is the Reservoir Bag?
What is special about the Reservoir Bag on this circuit?
- FGF inlet - near patient
- Reservoir Bag - on the operator side
- Reservoir Bag is open
How can pressure be generated in the Mapleson F Circuit since it doesn’t have an APL valve?
- The reservoir bag hole may be occluded by the operator’s hand to control bag distension and pressure
- OR fitted with a pop-off/PEEP valve for more precise control.
For MAPLESON F Circuit:
What is the FGF rate?
- 2-2.5 x minute ventilation
similar to Mapleson D circuit’s FGF rate
Improved rebreathing efficiency is due to what factor?
A. Amount of FGF
B. Minute ventilation
C. Location of the pop-off valve relative to FGF
D. Whether or not there is a CO2 absorber
C. Location of the pop-off valve relative to FGF
FGF located near patients will experience less rebreathing.
Which Mapleson Circuits will experience significant amounts of fresh gas vented through pop-off at end-expiration? Select 2.
A. mapleson A
B. mapleson B
C. mapleson C
D. mapleson D
E. mapleson E
F. mapleson F
B. Mapleson B
C. Mapleson C
see the FGF leaving thru APL near pt
Which systems have FGF drives that drive exhaled alveolar gas away from pt? hint t piece ones
A. Bain’s circuit
B. Maplesons DEF
C. Mapleson AB
D. Ayre’s
B. Mapleson DEF
Rank the groupings of the Mapleson Circuit in efficiency for spontaneous ventilation.
- Mapleson A > Maplesons DFE > Maplesons CB
Rank the groupings of the Mapleson Circuit in efficiency for controlled ventilation.
- Mapleson DFE > Mapleson BC > Mapleson A
What are the advantages of the Mapleson Circuit?
- 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
What are the disadvantages of the Mapleson Circuit?
- Require high FGF (can be wasteful)
- Conservation of heat and humidity less efficient
- Scavenging challenging (Except Mapleson D)
- Not suitable for patients with MH (May not be possible to increase FGF to remove excess CO2)
What does a Circle System allow for with Spontaneous Inspiration?
A. straight, multidirectional flow
B. straight, unidirectional flow
C. circular, unidirectional flow
D. circular, multidirectional flow
C. circular, unidirectional flow
Circle System: Spontaneous Expiration
During what respiratory cycle phase will the CO2 absorber experience the highest potential of drying out?
- End of expiratory cycle d/t the fresh gas flow traveling retrograde because the inspiratory valve is closed.
For the Circle System, the extent of rebreathing and conservation of exhaled gases depends on _______.
- FGF
Higher FGF = less rebreathing but greater amount of gas wasted
3 Rules to prevent rebreathing:
- Unidirectional valve - must be located between pt and reservoir bag on both the inspiratory and expiratory limbs
- Fresh gas inflow - cannot enter circuit between expiratory valve and pt
- APL valve - cannot be located between the pt and the inspiratory valve b/c you will lose FGF!
What kind of circle systems are seen with contemporary/ modern systems?
Does rebreathing occur?
- Semi-closed circle system
- Partial rebreathing occurs, but some waste flow is vented through APL or waste gas valve of the ventilator
What is an example of a semi-closed circle system?
A. ICU vents
B. Non-rebreathing system
C. High-flow anesthesia
D. Low-flow anesthesia
D. Low-flow anesthesia
Low-flow = FGF is less than minute ventilation but 50% of expired gas is rebreathed after CO2 removal
What percentage of expired gas is rebreathed after CO2 removal during low-flow anesthesia?
50%
What kind of circle systems are considered non-rebreathing?
Semi-open Circle System
Higher FGF with minimal rebreathing and more venting of waste gas
What are examples of semi-open circle systems? Select 2.
A. high flow anesthesia
B. scuba gear
C. low flow anesthesia
D. post-op and ICU vents
B. Scuba gear
D. Post-Op and ICU vents
In a closed circle system, how does the oxygen inflow rate correspond to the metabolic demand?
A. O2 inflow rate is less than metabolic demand
B. O2 inflow rate is greater than metabolic demand
C. O2 inflow rate exactly matches metabolic demand
D. O2 inflow rate is not related to metabolic demand
C. O2 inflow rate exactly matches metabolic demand
Complete rebreathing; no waste gas is vented
What is an example of a closed circle system?
A. high flow anesthesia
B. Low- and minimal-flow anesthesia
C. icu vents
D. scuba gear
B. Low- and minimal-flow anesthesia
Impractical for use – rarely done
Advantages of Low-Flow Anesthesia
- Decreased use of volatiles
- Improved temperature and humidity control
- Reduced environmental pollution
Disadvantages of Low-Flow Anesthesia
- Difficulty rapidly adjusting the anesthetic depth
- Possibility of accumulating unwanted exhaled gases ( ex: CO, acetone, methane)
- VA degradation by-products (ex: CO, compound A)
Advantages of Circle System
- Low FGF can be used
- Elimination of CO2
- Relatively stable inspired gas concentration
- Conservation of moisture/heat/gases
- Prevention of OR pollution
Disadvantages of Circle System
- Complex design
- CO or compound A
- May compromise Vt during controlled ventilation (Vt could be lost to corrugated tubing)
- ASA Closed Claims Project (#1 problem = Misconnections/ disconnections)
Components of the Self-Inflating Manual Resuscitators (AMBU bags)
- Self-expanding Bag
- T-shaped non-rebreathing Valve
- Bag Inlet Valve
- Pop-off valve
- Excess oxygen venting valve
- Oxygen reservoir
What is Self-Inflating Manual Resuscitators Used for? Select 2
A. post-op vent
B. pt transport
C. deliver extra PIP
D. emergency back-up
B. Pt transport
D. Emergency back-up
also for CPR and Hand ventilation in the absence of an oxygen or air source
Hazards of Self-Inflating Manual Resuscitators
- Barotrauma or gastric insufflation
- Significant variation of tidal volume, PIP, and PEEP
- Nonrebreathing valves generate resistance
BSN
What is the purpose of bacteria filters?
A. to release heat so that bacteria doesn’t grow
B. to supply humidity to tubing
C. to block bacteria from traveling backward up the ETT
D. routine use to prevent contamination or infection by airborne diseases
D. Routine use to prevent contamination or infection by airborne diseases (TB, COVID, PUI)
ALSO: Effective at preventing contamination of anesthesia machine from airborne diseases
Where are bacteria filters placed on the breathing circuit?
A. expiratory limb
B. inspiratory limb
C. both insp and exp limbs
D. on Y piece
A. expiratory limb
Related to Bacteria Filters:
- Due to the small-pore compact matrix, there will be ________ (high or low) airflow resistance.
- The small-pore compact matrix is also pleated to create a larger ________.
A. diameter
B. surface area
C. turbulent flow
D. opening
- high airflow resistance
- B. surface area
Hydrophobic Bacterial Filters will prevent _____.
A. CO2 leaks
B. CO2 penetration
C. water leaks
D. water penetration
D. water penetration
What happens if the hydrophobic Bacterial Filters become wet? Select 2.
A. increase resistance
B. decrease resistance
C. increase efficiency
D. decrease efficiency
E. increase flow
A. Increase resistance
D. Decrease efficiency
Where are combination filters (filter + HME) placed in the breathing circuit?
A. Y piece
B. inspiratory limb
C. expiratory limb
D. sample line tubing
A. at the Y-piece
But this will cause a barrier to inspiratory and expiratory limb, which increases resistance.
What are the 2 complications of Bacterial Filters? Select 2.
A. obstructions
B. breaks
C. leakage
D. twisting of tubing
E. disconnections common
A. Obstructions - sputum, edema fluid, nebulized aerosols, or malpositioning
C. Leakage of the housing of a gas line filter (monitor ETCO2 before the filter!!)
When is an inspiratory limb filter recommended?
A. when inspiratory limb disconnected from machine
B. when machine may have been contanimated by previous patient
C. when you place one on the expiratory limb
D. when the patient is already confirmed with airborne infection
B. when machine may have been contaminated by the previous patient
Expiratory limb filter recommended for ALL patients.
Define Humidity.
Amount of water vapor in a gas
Define absolute humidity.
Mass of water vapor present in a liter of gas (mg H2O/L of gas)
34-38 mg of H2O/ L gas in mid trachea
Define relative humidity.
Percent saturation; the amount of water vapor at a particular temp
95-100% in mid-trachea
Define water vapor pressure.
pressure exerted by water vapor in a gas mixture
Which body cavity does inspired gas make maximal contact w/ largest mucosal surface area?
A. laryngeal cavity
B. Pharyngeal cavity
C. Oral cavity
D. Nasal Cavity
Nasal Cavity
large mucosal surface area!
By what point in the airway does most of the heating and humidification of inspired gas occur?
A. oropharynx
B. mid-trachea
C. larynx
D. nasopharynx
B. Mid-trachea
temp: 34 C
absolute humidity: 34-38 mg H20/L
relative humidity: 95-100% in mid-trachea
What are effects of cold ambient temperatures regarding humidification in the airway?
A. Little capacity to hold water vapor
B. Low absolute humidity
C. Upper airway transfers large amounts of heat and moisture
D. A and C
E. All of the above
E. all of the above
* Little capacity to hold water vapor
* Low absolute humidity
* Upper airway transfers large amounts of heat and moisture
What is the effect of warm ambient temperatures regarding humidification in the airway?
A. Large amounts of heat energy used
B. Little capacity to hold water vapor
C. Low absolute humidity
D. Little heat energy is expended to warm inspired gases
D. Little heat energy is expended to warm inspired gases
Cool inspired gases may trigger _________.
A. shivering
B. bronchospasm
C. cough
D. rhinorrhea
B. Bronchospasm
noted for asthmatics
What are effects of underhumidifaction? Select 2.
A. secretions thicken
B. body heat increases
C. less risk of tracheal tube obstruction
D. increased resistance and work of breathing
E. surfactant functions more effectively
A. Secretions thicken –> Ciliary function decreases –> Surfactant activity is impaired –> Mucosa susceptible to injury
D. Increased resistance and work of breathing from thickened secretions
Damage to the respiratory tract
Body heat loss
Tracheal tube obstruction
What are the effects of overhumidifaction? select 3.
A. inefficient mucociliary transport
B. less airway resistance
C. risk of pulmonary infection and V/Q mismatch
D. increased mucosal viscosity
E. Obstruction to sensors
F. secretions get dried out
Condensation of water in the airway causes:
A. Inefficient mucociliary transport
C. risk of pulmonary infection, surfactant dilution, atelectasis, and V/Q mismatch, airway resistance
E. Obstruction to sensors (clogged water trap! just dump the water out)
and REDUCED mucosal viscosity and risk of water intoxication
What are the 2 types of humidification devices?
A. saline sprays
B. humidifiers
C. bacterial filters
D. HME
B. Heated humidifiers (Active humidification)
D. Heat and moisture exchanger (Passive humidification and can be modified to have a filter)
What is the main function of a Heat and Moisture Exchanger (HME)?
A. Conserves the exhaled volatiles and returns them to the pt
B. Conserves bacteria so it doesn’t go to the patient
C. Conserves some exhaled heat and water and returns them to the pt
D. Conserves CO2 and returns them to the pt
C. Conserves some exhaled heat and water and returns them to the pt
if HMEF = Bacterial/viral filtration and prevention of inhalation of small particles as well as humidification
Where is the placement of a HME?
A. between Y piece and distal end of bacterial filter
B. between distal end of ETT and Y piece
C. between Y piece and proximal end of LMA
D. between proximal end of reservoir bag and bellows
C. between Y piece and the proximal end of ETT or LMA
so close to the patient!!!
What happens to the ETCO2 reading if the sensor is placed AFTER the HME?
A. Lower ETCO2 reading
B. Higher ETCO2 reading
C. No changes
D. Water trap gets plugged causing higher ETCO2 reading
A. Lower ETCO2 reading
HME ends up trapping some of the exhaled gas
Does the HME increase or decrease:
the resistance in circuit?
the dead space in the circuit?
↑ resistance and ↑ dead space in circuit
When patient takes in a large tidal volume, does the efficiency of the HME increase or decrease?
↓ Efficiency
What describes a Hygroscopic HME and why does these matter to us? Select 2.
A. pleated with small pores to filter pathogens
B. Paper or other fiber barrier coated with moisture-retaining chemicals
C. can help decrease inspiratory resistance
D. only useful for pts with active airborne infection
E. absorb water in exhalation and release it in inspiration
B. Paper or other fiber barrier coated with moisture-retaining chemicals
E. Absorb water in exhalation and release it in inspiration
May have some electrostatic properties
What is Hygroscopic HME most efficient at? Select 2
A. increasing temperature of gas
B. releasing moisture
C. retaining heat
D. releasing heat
E. retaining moisture
F. decreasing temperature of gas
- Most efficient at C. retaining heat and E. moisture
What is a drawback of Hygroscopic HME?
A. Prone to becoming saturated
B. Can disconnect easily
C. Decreases expiratory resistance
D. increases heat and moisture retention efficiency
A. Prone to becoming saturated
which can increase inspiratory/expiratory resistance and reduce heat and moisture retention efficiency
What describes a Hydrophobic HME and why do they matter to us? Select 2.
A. paper or other fiber barrier
B. pleated with small pores
C. most efficient at retaining heat and moisture
D. has electrostatic properties
E. more efficient filters of pathogens
F. Channeling can occur
B. Pleated hydrophobic membrane with small pores
E. More efficient filters of pathogens
Name for devices used to actively increase the humidity in O2 supplied to pts?
A. Humidifiers
B. HME
C. Filters
D. Absorbents
A. Humidifiers
Which patient populations (directly from her ppt) benefit from humidifiers? Select 3.
A. Pts with dormant TB
B. Pts with 1 lung
C. Neonates
D. Pts with respiratory secretions
E. Hypothermic pts
F. COPD pts
C. Neonates
D. Pts with respiratory secretions
E. Hypothermic pts
NPH
What are the 4 different ways a humidifier can pass a stream of gas?
- Bubble or cascade
- Pass-over
- Counter-flow
- Inline
Where are the humidifiers placed in the breathing circuit? Select 2.
A. next to y piece
B. Inspiratory limb
C. upstream of the unidirectional valve
D. expiratory limb
E. downstream of unidirectional valve
Placed in the:
B. inspiratory limb
E. downstream of the unidirectional valve
Heated humidifiers should not be placed in the expiratory limb
What effect does condensation have on tidal volume?
A. Increases Vt
B. no change
C. increases Vm
D. decrease Vm
E. decreases Vt
E. Decrease Vt
What must you do with water traps?
A. leave them alone as long as not wet
B. change on every single case
C. change frequently to decrease risk of contamination and infection
D. change only when its clogged
C. Change frequently to decrease the risk of contamination and infection
What are 2 advantages of humidifiers?
A. Can deliver saturated gas at body temp or higher
B. More effective at retaining heat and moisture
C. Can conserve exhaled heat and water
D. more effective than HMEs at filtering pathogens
E. more effective than HME in longer cases in preventing hypothermia
A. Can deliver saturated gas at body temp or higher
E. More effective than HME in longer cases in preventing hypothermia
What are some disadvantages of humidifiers?
A. bulky
B. Potential electrical malfunction and/or thermal injury
C. contamination
D. water aspiration risk
E. all of the above
E. all of the above
* Bulky
* Potential electrical malfunction and/or thermal injury
* Contamination, and cleaning issues
* Higher cost than HME
* Water aspiration risk
