Anesthesia Equipment & Technology(test 2) Flashcards Preview

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Flashcards in Anesthesia Equipment & Technology(test 2) Deck (110):
1

What 2 factors affect the resistance of flow in the patients anesthesia circuit?

1. width of tubing
2. length of tubing

2

What effects does the resistance of the anesthesia circuit have on the patient?

increases the work of breathing such that a spontaneously breathing patient under anesthesia should always be assisted

3

What are the advantages of using a rebreathing circuit?

1. cost reduction
2. increased warmth and humidity of inspired gases
3. decrease of OR contamination

4

What effects do higher FGF have on rebreathing?

Higher FGF is associated with less rebreathing and the higher the FGF the more gas concentration in circuit will resemble that at the common gas outlet

5

What are 3 effects of rebreathing?

1. heat and moisture retention
2. altered inspired O2/CO2
3. altered agent concentrations

6

What factors affect rebreathing(4)?

-FGF
-apparatus dead space
-breathing system design
-empty space

7

How is hypercarbia avoided as related to dead space ventilation?

to avoid hypercarbia with increased dead space....minute ventilation must increase(alveolar ventilation = VE - VD)

8

What are 4 characteristics of a non-rebreathing circuits(4)?

-low resistance
-less dead space/empty space
-lack of unidirectional valves
-lack of CO2 absorption

9

What is the most popular non-rebreathing circuit?

Mapleson D;

10

Why is the Mapleson D the most popular non-rebreathing circuit?

as excess gas savaging is easy and most efficient during controlled ventilation
*D group most common*

11

What is the Bain modification to the Mapleson circuit?

involves placement of the FGF through the expired gases to heat inspired gases
*FGF runs inside the corrugated tube*

12

What are the advantages of using a NRB circuit(6).

* inexpensive, rugged, excellent method to deliver + pressure ventilation
* variations in minute volume affects ETC02 less (less dead space)
* in bain system: insp. limb heated by warm exhaled gases
* Resistance usu very low (supports spontan. ventilation)
* less drag on mask or ETT (lightweight)
* changes in fresh gas concentrations—> result in rapid changes
* no carbon monoxide or compound A (no C02 absorbent)

13

What are the disadvantages of the NRB circuit

* High FGF required (1.5x minute ventilation)— resulting in pollution and economic
waste
* low inspired heat and humidity— bc higher FGF
* requires frequent adjustment in FGF
* Not suitable for pt with MH history—> bc inability to increase FGF enough to blow
off C02

14

What are 3 reasons for a decline in the use of NRB circuits?

1. modern efficient ventilators
2. conservation of heat with rebreathing circuits
3. waste gas management

15

What are the advantages of the circle systems(rebreathing circuits?

* economical:
‣ expired oxygen reused
‣ anesthetic vapor reused
‣ FGF & anesthetic agent utilization are minimized
* Humidifies inspired gas
* Preserves heat and pt temp

16

What are the disadvantages of the circle systems?

* Complex
* less portable than non-rebreather
* opportunities for disconnect
* unidirectional valves may malfx
* incr. dead space
* incr. “empty space” (longer diffusion time)

17

Describe the basic configuration of the circle system in regard to location of the ventilator/bag, FGF and carbon dioxide absorbent

1. FGF enters circuit from CGO of anesthesia machine
2. FGF through the one-way valve on the inspiratory limb of the anesthesia circuit toward the patient Y
3. is exhaled from patient and goes through the one-way valve on the expiratory limb of the anesthesia circuit
4. enters and exits reservoir bag
5. excess gas if vented out through the pop-off valve to scavenging system(APL)
6. through the absorbent canister where CO2 is removed
7. then back to the patient

18

Compare semi-closed circle systems to closed and semi-open systems

Semi-closed:
-delivers positive pressure
-delivers oxygen and anesthetic gas
-Removes waste and anesthetic gas
-*Conveys excess gas to scavenging system*
-*Humidification*
-Nominal dead space
-*Low FGF*

Semi-Open:
-Delivers positive pressure
-Delivers oxygen and anesthetic gas
-Removes waste and anesthetic gases
-*Excess gas released into air*
-*No humidification*
-Minimal dead space
-*High FGF(1.5xMV)

19

What are 2 functions of the APL valve?

* releases gas into scavenging system
* controls pressure in breathing circuit

20

What are the basic characteristics of carbon dioxide absorbents(5)?

• Gas tends to travel along periphery (outside) of canister and inlet
• Carbon dioxide absorbers do not support bacterial growth
• Each canister should last 20-30 hours (25 liters of carbon dioxide per 100 grams of absorbent)
• Each canister is approximately 55% granules, 45% air space
• Smaller granules absorb more but create more dust and “cake” or harden, so usually a mixture of large and small are packaged

21

Identify moisture content and granule size of common carbon dioxide absorbents

• Soda lime: 14-19% water; 4-8 mesh granules
• Baralyme: ?
• Medisorb: 16-20% water; 4-8 mesh granules
• Dangersorb: 14% water; 4-8 mesh granules
• Ansorb: 14.5% water; 4-8 mesh granules

22

Describe the chemical reaction involving CO2 and soda lime

• Reaction occurs as water (H2O) reacts with carbon dioxide (CO2) to produce carbonic acid (H2CO3) and heat (canister may become warm)
• H2CO3 (acid) then reacts with the base in the soda lime (sodium hydroxide, or NaOH) to form sodium carbonate, water and heat
• CO2 + H2O = H2CO3
• H2CO3 + 2 NaOH=Na2CO3 + CO + 2 H2O + Heat
• Na2CO3 + Ca(OH)2=CaCO3+ 2 NaOH
• Water is necessary to react with CO2, dissipate heat and humidify gases

23

List common clinical signs(7) of CO2 canister exhaustion

1. rise in heart rate(later will fall)
2. increased respiratory rate
3. respiratory acidosis
4. dysrhythmia
5. signs of SNS activation(flushed, sweating)
6. increased bleeding
7. increased ETCO2

24

Describe the function of the expiratory valve on the circuit

The expiratory valve closes to prevent rebreathing of exhaled gas that still contains CO2. Valve incompetence is usually due to warped disks or seat irregularities. The exp. valve is especially vulnerable since it is exposed to the humidity of expired gas.

25

Identify measurement units for airway pressure

kPa or cm H20

26

What are the 4 uses of the pressure gauge?

1. used to measure circuit pressure between inspiratory and expiatory valves
2. higher pressures reflect change in compliance or resistance
3. lower pressures reflect circuit leak
4. pressure higher than 20 cmH20 opens esophageal sphincter(mask induction or anesthetic)

27

What are 4 uses for the reservoir bag?

1. provides a means for delivering positive pressure
2. can serve as a monitor for spontaneous ventilation
3. allows the use of lower FGF
4. protects the patient from excessive pressure in the breathing circuit

28

What are 3 characteristics of a closed system?

1. oxygen supply equals metabolic consumption of the patient(no "waste" of oxygen, hence term "closed circuit")
2. extremely economical as far as fresh gas and agent
3. retains more heat and humidity
4. less environmental pollution

29

What are 3 breathing circuit hazards?

1. circuit disconnection is a leading cause of critical incidents and the most common place this occurs is at the Y
2. inability to ventilate secondary to a leak in the circuit.

To detect leaks and disconnects---> circuit must be check by a positive pressure test

30

What is the component of the machine check that verifies an intact circuit?

To detect leaks and disconnects circuit must be checked by inflating and testing ability to hold positive pressure.

31

List 5 criteria activating a ventilator alarm.

• High pressure
• Pressure less than volume or pressure threshold for greater than 15 seconds
• Continuing high pressure
• Subatmospheric pressure
• Low tidal volume or minute ventilation
• High respiratory rate
• Reverse flow (incompetent expiratory limb valve)
• Apnea/disconnect alarm

32

List 5 causes of increased peak inspiratory pressure.

• Increased tidal volume
• Decreased pulmonary compliance
• CHF
• Trendelenburg
• Pleural effusion
• Abdominal packing/insufflation
• Obesity
• Tension pneumothorax
• Endobronchial intubation
• Increased airway resistance
• Kinked ET tube, airway compression
• Bronchospasm
• Secretions/foreign body

33

List 2 disadvantages to using descending ventilator bellows.

• Inability to visually detect leak
• Leak causes room air to enter the bellow
• Tidal volume lost but unknown to CRNA

34

List 2 advantages and disadvantages associated with an electronic(piston) ventilator.

• By eliminating the need for a drive gas circuit, a more stable flow can be provided
• Tidal volume more precise
• Reservoir bag is NOT isolated from breathing system and acts to modulate pressure increases in the system
• During inspiration, the bag is isolated from the breathing system and collects FGF from breathing system (bag expands and contracts)
• Disadvantages include lack of conventional bellows (up and down), no audible excursion of bellows and limited ability to adapt to nonrebreathing circuit

35

Identify a risk involved with switching ventilator modes during an anesthetic

• Must be careful when switching between modes to assess compliance changes (PIP and/or VT may be inappropriate)

36

Identify the most commonly used mode of ventilation and why it is used.

• Volume control
• Preset tidal volume is administered, independent of patient effort
• Flow rate is fixed at a constant value during inspiration
• Changes in compliance or resistance are reflected in changes in PIP
• Delivers a set volume at a set flow rate with pressure dependent on compliance and resistance
• Flow is constant throughout the inspiratory cycle (square waveform)
• Pressure increases throughout the inspiratory cycle
• Pressure waveform resembles a shark fin
• Rate of volume increase is linear

37

Define volume control ventilation(flow pattern, effect of compliance and resistance).

• Preset tidal volume is administered, independent of patient effort
• Flow rate is fixed at a constant value during inspiration
• Changes in compliance or resistance are reflected in changes in PIP
• Delivers a set volume at a set flow rate with pressure dependent on compliance and resistance
• Flow is constant throughout the inspiratory cycle (square waveform)
• Pressure increases throughout the inspiratory cycle
• Pressure waveform resembles a shark fin
• Rate of volume increase is linear

38

Define pressure control ventilation(flow pattern, effect of compliance and resistance).

• Ventilator generates pressure to set level and maintains flow
• Decelerating inspiratory flow allows alveolar recruitment (flow rates are NOT fixed)
• Tidal volume may fluctuate with changes in resistance and compliance
• Reaches a preset pressure but achieves a target volume
• Volume achieved depends on compliance and resistance
• Pressure is constant throughout the inspiratory cycle
• Flow decreases as pressure in lung decreases (plateaus) but peak flow remains the same
• Increased mean airway pressures
• Improved alveolar recruitment from decelerating inspiratory phase
• Recruits slow alveoli

39

Identify advantages and disadvantages to the use of pressure controlled ventilation(PCV).

• Advantages
• Decelerating inspiratory phase allows recruitment of slow alveoli
• PCV improves oxygenation with lung injury, OLV and obese as gas is delivered to less complaint alveoli

• Disadvantages
• Tidal volume fluctuates with changes in resistance and may be very low or high
• Increasing respiratory rate decreases inspiratory time and lowers tidal volume
• PEEP decreases tidal volume

40

Identify 2 patient populations that may benefit from PCV.

• Lung injury, OLV, obese

41

Describe the potential effects of I:E manipulation on patients with lung disease.

• Reverse I:E ratio
• Alveolar recruitment may be improved by prolonging the inspiratory period
• Slow alveoli are recruited similar to pressure control
• May be problematic in obstructive lung disease with “stacking”

• Longer I:E ratio
• Prolonged expiratory phase (1:3 or 1:4) allows compensation for flow related collapse
• Medium sized airways (generations 11-14) stay open longer
• FRC potentially improved through recruitment via “pseudo-PEEP”

42

List 2 settings which require manual adjustment during the use of SIMV and why they are necessary.

• Minimum minute ventilation must be selected
• pressure support ventilation

43

Compare SIMV and PSV(differences between the two modes, which mode is best used for an LMA).

• Designed to augment patient’s spontaneous breaths by supplying positive pressure in response to patient-initiated breaths
• Support may be pressure or flow initiated and is usually used with LMA
• Support usually pressure-based (tidal volume determined by pressure, lung compliance etc.)
• Back-up or “apneic” SIMV rate is usually part of this mode
• Psv best for LMA

44

List 3 advantages of PEEP

• Increases lung compliance and recruits alveoli
• Increases functional residual capacity
• Decreases ventilation-perfusion mismatch*
• Increases tidal volume above closing volume
• Redistribution of extravascular water

45

List 3 disadvantages of PEEP.

• May decrease venous return and blood pressure
• Potential for barotrauma
• *May worsen V/Q with OLV

46

Identify the typical minimum tidal volume with modern ventilators

• 20 mls

47

Identify the standard delivery pressure of oxygen during jet ventilation

• 50 psi

48

List 3 complications of jet ventilation


*hypercapnia
*hypoxia
*inhalation of foreign substances
• Gastric distention
• Barotrauma
• SQ emphysema
• Pneumothorax
• Ball-valve distention from tumor
• Distal bronchial seeding from tumor
• Hypoventilation

49

Identify the government agency that regulates trace gases

• OSHA

50

Identify the typical capacity of waste gas disposal in an anesthesia machine.

• The vacuum control should be adjusted to allow the evacuation of 10-15 liters of waste gas per minute

51

List 4 practices that minimize exposure to anesthesia gas

• Disconnect pipeline hoses from wall outlets and turn off cylinders at end of day
• Never sniff an agent (25x more than recommended limits)
• Avoid turning any agent on until face mask is on patient
• Avoid unnecessary disconnects of circuit
• Turn off gas and empty reservoir bag into APL prior to disconnect
• Administer 100% oxygen prior to removing airway device
• Install key-filled vaporizers whenever possible
• Connect Bain and Mapleson circuits to specialized waste adaptors when possible

52

List 4 sources of hypercapnia during anesthesia

• Hypoventilation (ETCO2 is not PCO2 )
• Inadvertent carbon dioxide administration (some machines have CO2 tanks, broken pin index system)
• Rebreathing (absorbent failure, bypassed absorbent, unidirectional valve problems such as wet, sticky)
• Inadequate FGF to Mapleson system
• Excessive dead space
• Covered face during MAC

53

List 5 sources of accidental excessive airway pressure during anesthesia

• High inflow (oxygen flush valve, closed APL valve)
• Low outflow (obstruction in expiratory limb/valve, PEEP valve inserted backward, pediatrics with use of t-piece)
• Ventilator spill valve malfunction
• Obstruction in scavenging system
• Misconnected oxygen tubing (connection of oxygen directly to trach or LMA, t-piece with closed limb)
• Unintentional PEEP (water condensed in tubing, inadequate opening of Mapleson F circuit)

54

List 5 sources of inadvertent anesthetic agent overdose or underdose

• Overdose
• Tipped vaporizer (fills chamber and increase concentration)
• Vaporizer or nitrous inadvertently turned on (ALWAYS check vaporizer before starting case)
• Incorrect agent in the vaporizer
• Improper vaporizer installation (be leary of mission trips)
• Overfilled vaporizer (difficult with keyed vaporizers)
• Vaporizer interlock failure (turning on more than one vaporizer at a time)

• Underdose
• Decreased nitrous oxide flow (accidentally using air, leaks)
• Unexpectedly high oxygen concentrations (repeatedly using oxygen flush)
• Air entrainment
• Faulty vaporizer or vaporizer leak (hence low pressure system check)
• Incorrect vaporizer setting (duh)
• Empty vaporizer (double duh)
• Incorrect agent in vaporizer
• Anesthetic agent breakdown

55

List 5 maneuvers employed for MH history

• Remove all vaporizer from machine
• Remove soda lime canisters
• Remove circuit
• Replace fresh gas hose
• Consider new bellows vs. ventilating into circuit
• Turn fresh gas flow to 15 liters/minute
• Flush circuit/machine for 30”
• New soda lime, no vaporizers on machine

56

List 4 protective features of modern anesthesia machines

• Fewer user accessible connections
• More accurate tidal volume delivery
• Prevention of excess volume delivery
• Limitation of excess airway pressure
• Advanced ventilation features
• Lower fresh gas consumption
• Low flow enhancements
• New vaporizer technologies
• Automated checkout systems
• Sophisticated alarms

57

Identify 4 standard monitors for the intubated patient undergoing general anesthesia

• FiO2, pulse oximetry, capnography, ecg, bp

58

Describe the role of the oxygen analyzer in avoiding a hypoxic mixture of gases


• *ASA standard to have oxygen analyzer in inspired limb, only machine monitor that measures downstream from flowmeters
• Galvanic/Polarographc (plug in):
• Calibrate to 21% (room air)
• > 60 seconds need to change sensor
• Expose to 100% oxygen and make sure it is close
• Most common in anesthesia machines
• Paramagnetic
• Expose to calibration gas every 6 months
• Most clinicians make sure it reads 21% every morning

59

Identify the single monitor which provides the most clinical information

• Pulse oximetry: Oxygen saturation, Heart rate, Blood pressure, Circuit disconnect, esophageal intubation

60

List wavelengths of oxygenated and deoxygenated blood and describe how this generates pulse oximeter readings

• Oxygenated (960 nm) and deoxygenated blood (660 nm) differ in their absorption of red and infrared light (Lambert-Beer Law)
• Change in light absorption when passing through vascular bed during arterial pulsation is the basis for oximetric readings

61

List 3 clinical scenarios which may result in decreased oxygen saturation

• Prior to induction (polycythemia)
• Ventilation/Perfusion mismatch
• Disconnect
• Inadequate MV
• Misplaced ET tube
• Diffusion abnormality

62

List 8 locations which may be used to monitor oxygen saturation

• Finger (convenient, most accurate)
• Nose (inconvenient, poor signal)
• Earlobe (better signal than nose but comes off)
• Forehead (ocular artery, less dependent on good perfusion)
• Lip, tongue, cheek, forehead

63

List 8 factors affecting pulse oximeter accuracy

• Electrocautery
• Motion, venous pulsations
• Ambient light/radiant warmers
• Nail polish, acrylic nails, second probe
• Low perfusion
• CO, Methemoglobin
• Methylene blue/indigo carmine (false low)
• Hypothermia
• Tourniquet
• Nonpulsatile flow (CPB)
• IABP (two systoles)

64

Identify monitoring standards for accuracy, signal adequacy and mandatory alarms(in reference to saturation)

• Accuracy between 70-100%, if accurate below 65% must be stated by manufacturer
• If affected by motion must be stated
• Must be an indication if lag time for data
• Mandatory alarm for sat < 85%
• Indication for signal inadequacy (e.g., perfusion index)

65

List 4 uses for pulse oximetry besides measuring oxygen saturation

• Estimate of systolic blood pressure
• Monitoring peripheral circulation
• Mediastinoscopy
• Shoulder surgery
• Locating arteries
• Warning of fluid extravasation

66

Identify the most commonly used technology used for anesthesia gas monitoring

• Infrared analysis

67

Describe how infrared technology works in relation to measuring anesthesia gas concentration

• IR based on the principle that gases with two or more dissimilar atoms have specific infrared light absorption
• The amount of IR light absorbed is proportional to the concentration of the absorbing molecules (usually oxygen, nitrous, CO2)
• Gas concentration may be determined by comparing IR light absorption to known standard

68

Compare and contrast limitations of non-diverting and diverting gas monitors

Non-diverting
• “Mainstream” gas monitors
• Sensor located directly in gas stream
• More accurate
• No gas is removed from breathing system
• Must be placed close to patient (cumbersome)
• Expensive

Diverting
• Requires water trap for condensation
• Accuracy decreases with increasing RR and longer sampling lines
• Requires tidal volume 150 ml
• Must be beyond HME
• Particulate matter may clog line
• If FGF high may have dilution
• Larger gradient than nondiverting/mainstream but less cumbersome

69

List 4 limitations of IR technology

• Gas interference
• Oxygen may interfere with CO2 accuracy
• Overlap of CO2 and nitrous IR peaks
• Mixture of agents causes erroneous readings
• Interference from water vapors

70

Discuss accuracy standards for capnometry

• ET tube and LMA must be verified by CO2
• CO2 reading will be within 12% of the actual value or 4 mmHg
• Manufacturer must disclose any interference by inhalation anesthetics
• Capnometer must have a high CO2 alarm for both inspired and exhaled CO2
• An alarm for low exhaled CO2 is mandatory

71

Describe mandatory alarms for capnometry.

• Capnometer must have a high CO2 alarm for both inspired and exhaled CO2
• An alarm for low exhaled CO2 is mandatory

72

List 4 factors associated with a decrease in ETCO2

• Hyperventilation
• Respiratory obstruction
• Poor mask/LMA fit
• Malposition of ET tube
• Embolism/Hypoperfusion
• Diffusion issue
• Cardiac arrest

73

List 4 sources of heat loss during anesthesia

• Heat losses occur from radiation (60%), evaporation (20%), convection (15%) and conduction (15%)

74

List 4 critical clinical events detectable by gas analysis

ELEMENTS THAT CHANGE CO2 PRODUCTION:
INCREASES IN ETCO2:
1. increased metabolic rate
2. hyperthermia
3. Sepsis
4. MH
5. shivering
6. hyperthyroidism

DECREASES IN ETCO2:
1. decreases in metabolic rate
2. hypothermia
3. hypothyroidism

ELEMENTS THAT CHANGE CO2 ELIMINATION:
Hypoventilation--->Rebreathing
Hyperventilation--->Hypo perfusion
Pulmonary Embolism

75

Identify 4 deleterious effects associated with hypothermia during anesthesia.

• Shivering (increase oxygen consumption 700%)
• Decreased metabolism of drugs
• Prolonged emergence
• Increased bleeding
• Nausea and vomiting
• Poor wound healing

76

Identify 5 clinical scenarios associated with a higher risk of hypothermia

• Elderly/Neonates/ Pediatrics
• Burn patients
• Patients with spinal cord injuries
• Open abdomen or chest
• Cold room

77

Identify the most effective method of keeping the patient warm

• Increase ambient temperature (MOST EFFECTIVE)

78

Identify the BIS range associated with a surgical plane of anesthesia

• 40-60

79

List 4 potential monitoring sites for nerve stimulators

• Ulnar nerve(Adductor pollicis-most sensitive)
• Ocular nerve (orbicularis orbiti)
• Median nerve
• Tibial nerve
• Posterior tibial nerve
• Peroneal nerve
• Facial nerve
• Mandibular nerve

80

Compare and contrast nerve stimulator monitoring for depolarizing and non-depolarizing muscle relaxants.

Non-depolarizing
• Decreased twitch height
• Fade during tetany
• Fade during TOF
• T4/T1 < 0.7
• Post-tetanic potentiation
• Absence of fasciculations
• Antagonism of block by Achase inhibitors
• Augmentation by NDMR
Depolarizing

81

List 5 clinical signs of neuromuscular function

• Head lift, leg lift (kids)
• Grip strength
• Maximal inspiratory force (NIF)
• Vital capacity
• Tidal Volume

82

Identify how excess drive gas and circuit gas from the ventilator is expelled

• Bellows re-expand as breathing system gases and fresh gas flow into it
• Driving gas is vented to atmosphere through the exhaust valve
• After bellows are fully expanded, excess circuit gas is vented to the scavenging system through the spill valve

83

Differentiate between modern ventilators based on power source and drive mechanism

Power Source and Drive Mechanism
• Gas-driven bellows
• Double circuit (driving gas O2 or room air)
• Piston ventilator
• Electric motor
• Cycling Mechanism
• Electronically time-cycled
• Flow cycled

84

List three factors that may affect the delivered tidal volume when using a ventilator

1. Fresh Gas Flow
• Older ventilators only (VT increased if FGF increased)
• New vents measure FGF and compensate by altering bellows excursion
• Another method diverts FGF into reservoir bag (fresh-gas decoupling)

2• Compliance and compression volumes
• Decreased lung compliance decreases VT as more inspiratory gas flow expended generating bellows excursion
• Newer vents compensate by altering delivered volume (measured at patient connection)

3• Leaks
• Leak around tube or supraglottic device will cause decrease in VT
• Sidestream sampling gas monitors may also decrease tidal volume

85

Define fresh gas decoupling

-With traditional ventilators tidal volume is affected by FGF
• Increased FGF increased tidal volume (decreased FGF decreased VT) (bad for kids)
• Modern ventilators/machines compensate tidal volume regardless of FGF by separating FGF from VT

86

List three standard alarms on modern ventilators

• High, medium, low priority based on immediate action, prompt action or operator awareness
• Standards mandate high pressure limit, as well as low pressure and minute ventilation alarm

87

List three disadvantages of using a face mask for general anesthesia vs. LMA

• Ties up hands, mask straps may be required
• Higher FGF required
• Access difficult during certain procedures
• *More desaturation vs. LMA*
• Higher work of breathing
• Poor correlation between ETCO2 and PCO2

88

Identify four complications from the use of a face mask

- Pressure necrosis
• Nerve injury (usually associated with mask)
• Gastric inflation
• Eye injury, jaw pain
• Cervical spine injury
• Pollution
• User fatigue
• Hypoventilation

89

Identify four methods of inserting LMA’s


• Head extended and neck flexed (sniffing position)
• Tube grasped as a pen, index finger pressing on the point where tube joins the mask
• LMA is advanced, with mask portion pressed against the hard palate with index finger
• Tube is grasped by the other hand and advanced until resistance is met
• Alternatively:

• Remove some of air from cuff, pull up on chin and advance
• Remove all of air from LMA and insert upside down into oropharynx
• Insert stylet into LMA, remove some of air from cuff, pull up on chin and insert
• Convert into modification of intubating LMA
• Very useful for flexible LMA

90

Identify two differences between an LMA classic and an intubating LMA

• LMA classic is more floppy to optimize alignment with glottis, does not accommodate an ETT
• Intibating LMA (Fastrach) Short curved stainless steel shaft, diameter sufficient to take 9.0 cuffed ET tube, Single moveable epiglottic elevator bar, Success rate of intubation 40-100%

91

List three complications of LMA insertion

- Aspiration of gastric contents
• Gastric distention
• Foreign body aspiration
• Airway obstruction (less reliable airway)
• Trauma (uvula edema)
• Dislodgement
• Laryngospasm/Bronchospasm
• Nerve injury

92

List three advantages of LMA vs ET tube

• Ease of insertion
• Smooth emergence
• Low operating pollution vs. mask
• Avoid face mask complications
• Avoid complications of intubation
• Protection from barotrauma

93

List three advantages of ET tube vs. LMA

• ETT is safer in prone/jackknife positions
• Does not limit max PPV
• More secure airway
• Less r/o gas leak and pollution
• No gastric distention

94

List two unconventional handle configurations and describe their use in specific populations

• Short handle better for obese and large breasts/chests or if patient in body cast
• Small handle better for pediatrics (does not obscure view)

95

List four uses of fiberoptic bronchoscopes (FOB)

• Intubation (awake or asleep), nasal or oral
• Confirm placement of endotracheal tube
• Confirm placement of double-lumen endotracheal tube
• Clear secretions
• Bronchoscopy with lavage for aspiration or blood in ET tube
• Bronchoscopic exam with intervention

96

List four disadvantages or limitations of FOB

DISADVANTAGES
• Expensive, fragile, difficult to use
• Requires more time and preparation
• Availability may be an issue
• Difficult or impossible with certain patients (blood, secretions, hypoxemia)
• Gastric distension, rupture have occurred with oxygen insufflation
• Laryngeal trauma has occurred
• Technical issues (light source, fogging, anatomy)

LIMITATIONS:
• Lack of experience (not practicing during routine intubations)
• Failure to adequately dry the airway
• Failure to adequately anesthetize the airway
• Nasal cavity bleeding (inadequate vasoconstriction)
• Obstructing base of tongue or epiglottis
• Inadequate sedation
• Hang up (e.g., ETT too large)
• Fogging of the FOB (suction or oxygen not attached, cold bronchoscope)

97

List four structures at risk of damage from direct laryngoscopy

• Dental injury
• Cervical spinal cord injury
• Damage to other structures
• Lips
• Tongue
• Palate
• Hypopharynx
• Larynx
• Esophagus
• TMJ dislocation

98

Identify the importance of sizing of RAE ET tubes in regard to the preformed bend

Sizing is very important as location of bend is determined

99

List two indications for armored ET tubes

• Used when an ET tube is placed in a tracheostomy
• Used when kinking of the ET tube is possible
• Prone
• Neck surgery

100

List two differences between a Microlaryngeal tube and a conventional ET tube

• Microlaryngeal tracheal tube used for ENT surgery
• Larger cuff
• Narrow body
• Longer body
• Same lumen

101

List three safety-enhancing physical characteristics of the laser ET tube

• Laser shield tube made from silicone with inner aluminum wrap
• Cuff is filled with blue indicator instead of air
• If cuff is hit the saline helps put out fire

102

List four complications of endotracheal intubation

• Trauma
• Esophageal intubation
• Inadvertent bronchial intubation
• Aspiration
• Leaks
• Tracheal tube fires
• Accidental extubation
• Upper airway edema
• Vocal cord dysfunction

103

Describe how determination is made of what size FOB to use for a specific ET tube and size

• Outside diameter determines size of ET tube or DLT used

104

List four clinical uses of fiberoptic bronchoscopy

• Intubation (awake or asleep), nasal or oral
• Confirm placement of endotracheal tube
• Confirm placement of double-lumen endotracheal tube
• Clear secretions
• Bronchoscopy with lavage for aspiration or blood in ET tube
• Bronchoscopic exam with intervention

105

Identify the type of oral airway used for awake fiberoptic intubation using the oral approach

• Oral use ovassapian airway, pull tongue

106

Identify the main advantage of using a nasal approach for awake FOB

• Nasal has most direct path to glottis

107

Identify three limitations of FOB

• Expensive, fragile, difficult to use
• Requires more time and preparation
• Availability may be an issue
• Difficult or impossible with certain patients (blood, secretions, hypoxemia)
• Gastric distension, rupture have occurred with oxygen insufflation
• Laryngeal trauma has occurred
• Technical issues (light source, fogging, anatomy)
• Lack of experience (not practicing during routine intubations)
• Failure to adequately dry the airway
• Failure to adequately anesthetize the airway
• Nasal cavity bleeding (inadequate vasoconstriction)
• Obstructing base of tongue or epiglottis
• Inadequate sedation
• Hang up (e.g., ETT too large)
• Fogging of the FOB (suction or oxygen not attached, cold bronchoscope)

108

List two anesthesia considerations with jet ventilation

• 100% oxygen is used, rise and fall of chest as monitor
• Inhalation is active with jet while exhalation is passive
• Surgeon will usually direct ventilations
• TIVA necessary as vaporizers are bypassed
• Oxygen is delivered under pressure through a reducing valve (15-30 psi) via a metal catheter
• Source is pipeline (45-55 psi)
• Flow/pressure is adjusted with reducing valve/knob
• Jet ventilation is typically performed in association with direct laryngoscopy by surgeon

109

Identify two relative contraindications to jet ventilation

• Complete upper airway obstruction
• Obesity or poor pulmonary compliance
• Distal foreign body
• Severe tracheal stenosis

110

List two complications from jet ventilation

• Gastric distention
• Barotrauma
• SQ emphysema
• Pneumothorax
• Ball-valve distention from tumor
• Distal bronchial seeding from tumor
• Hypoventilation