1
Q
Nose
A
Large surface area = primary passage providing air to lungs.
- Provides warmth, filtering, & moisture
- 2/3 of airway resistance
2
Q
What causes the soft palate to collapse?
A
- GA
- Sleep apnea
- Pregnancy
- Age
- Obesity= swelling of soft tissues
3
Q
What happens to the gag reflex during GA?
A
The gag reflex is blunted
- happens when the patient loses consciousness/ lash reflex
4
Q
What nerve branches into the recurrent laryngeal nerve ?
Where can this be found?
A
Vagus nerve
- Caution traction on this nerve can cause stretching:
Unilateral stretching = hoarseness
Bilateral stretching = stritor, cords floppy/addicted & can’t move
- Head and neck procedures are increased risk d/t R RLN being under the subclavian artery and the L RLN being under the aorta
5
Q
What 3 cartilages make up the larynx (C3-C6)
A
Arytenoid, Corniculate, Cuneiform
6
Q
4 Functions of the larynx
A
- Potency between hypopharynx and trachea
- Gag/cough reflex
- Protection from aspiration
- Phonation
7
Q
Where does the tip of the blade go during intubation?
A
Mac Blade = vallecula, anterior portion of epiglottis
Miller = pulls up posterior aspect of epiglottis
- epiglottis = key structure in intubation
8
Q
Where should the cuff be located ?
A
Below the level of the cords 1.5 - 2 cm
Or
Above the carina 4 cm
Average:
In women = 20 - 22 cm
In men = 22 - 24 cm
9
Q
The carina is sensitive to stimuli, what does this mean for intubation?
A
Increase HR & BP is 1st sign d/t sympathetic irritation
- subtle clue you are in the trachea
10
Q
What to assess with “maskability” ?
A
- Fatty airway - short thick neck
- Beard or other facial hair
- Anything blocking seal of mask (high nose, facial tumor, hematoma, burn)
- No teeth (do they have teeth, implants)
- BMI? (Increased BMI = decrease mask, swelling of soft tissue)
- Sleep apnea = collapse of soft palate
- Stiff lungs = low compliance = resisting air
11
Q
What are the classes of Mallampati Scores
A
Class 1 = Soft palate, fauces, uvula, pillars
Class 2 = Soft palate, fauces portion of uvula
Class 3 = Soft palate, base of uvula
Class 4 = Hard palate only
12
Q
What are the classes of Cormac Lehane Score
A
Classifies views obtained at the cords
Class 1 = Visualization of the entire glottis aperture
Class 2 = Visualization of just arytenoid cartilages (cuneiform & corniculate)
Class 3 = Visualization of epiglottis only
Class 4 = Visualization of tongue or of tongue and soft palate only
13
Q
What is the 3-3-2 Method?
A
- 3 finger tips between incisors
- 3 finger tips between jawline & hyoid bone (thyromental distance)
- 2 finger tips between hyoid & thyroid notch (Adam’s apple)
Absence of one or more raises likelihood of “anterior” larynx
- the more anterior = harder to intubate = higher cormac lehane & mallampati
14
Q
What are the indications for Tracheal intubation?
11
A
- High aspiration risk
- Anticipated/known difficult airway
- Intraoperative positioning (prone/lateral)
- Inability to oxygenate with supraglottic airway or mask
- Shared airway
- Surgery requiring paralysis
- Surgery affecting V/Q mismatch
- Prolonged surgical time (no SGA if > 2hrs)
- GCS < 10
- Critically ill affecting respiratory function
- Controlled management of CO2 (hence ICP)
15
Q
What are the three airway axes?
A
- Laryngeal axis
- Pharyngeal axis
- Oral axis
- need these to line up for better intubating conditions = sniff position
16
Q
Signs of poor masking (6)
A
- Poor tidal volumes
- Audible leak
- Poor chest rise/excursion
- No fogging
- Low Co2
- Decreasing O2 (late sign
17
Q
What can be altered to create better maskability
A
- Assure proper positioning = sniff position
- Consider using mask strap to seal leak
- Consider OPA (oralpharyngeal airway)
- Use two hands w/ assistant help
- Consider LMA or wake up the patient
18
Q
What are the 3 Fundamentals of a breathing circuit?
A
- Deliver O2
- Deliver anesthetic gas
- Eliminate Co2
- Washout
- Absorption
19
Q
What are 5 things that alter resistance in the breathing circuit?
A
- Diameter - smaller diameter = increased resistance
- Length - longer tube = increased resistance (have more air to shove)
- Bends - the more bends = increased resistance
- Valves - the more valves = increased resistance
- Laminar flow - straight path = decreased resistance
20
Q
What are the benefits of rebreathing/recycling?
4
A
- Warming
- Humidifying
- Lower cost
- Decrease anesthetic exposure for personnel
21
Q
What is dead space ?
A
Dead space = volume of air that is inhaled but does not partake in gas exchange
- occurs in the circuit where the FGF meets exhaled gas (Y-piece)
- increased dead space = decreased alveolar ventilation
- Spontaneously breathing patients increase RR to decrease dead space
- increased dead space = increased Co2
- In Anesthesia circuit you increase Vt to decrease dead space
- It is better to intubate than mask if you are worried about dead space b/c a mask has more
22
Q
True or False Humidification of the breathing circuit is an effective way of warming the patient in the OR.
A
False.
It is ineffective, warm blankets are better
23
Q
What is a disadvantage of humidification in the breathing circuit?
A
Humidity clogs:
- the sample line = inaccurate reading
- Soda Lyme = decreased removal of Co2
- Sticking of valves - Inspiratory & Expiratory
24
Q
What are the 4 types of breathing circuits and the differences?
A
- Open = no reservoir, no re-breathing
- nasal cannula, blow by
- Semi-open = reservoir bag, but no rebreathing
- High flow anesthesia, non-rebreather mask
- Getting 100% oxygen/FGF but exhaled gas goes out
- Semi-closed = reservoir bag, with partial rebreathing
- for the asleep but spontaneously breathing patient
- APL valve open (no peep, can turn APL valve to 5 or 10 to create Peep, partially closed)
- Flow less than MV
- Closed circuit = reservoir with re-breathing
- non-spontaneously breathing patient
- Ventilator or hand bagging (APL valve closed) - positive pressure ventilation
- LFA = less than MV
25
What are the 3 most common Mapleson circuits ?
| What are their alternative names and uses?
1. Mapleson D = Bain Circuit
- commonly used in peds
- reservoir, APL valve, & FGF close to patient
2. Mapleson E = T-piece
- used in recovery, open-ended attached to ETT
- No reservoir or APL
3. Mapleson F = Jackson Reece
- Used in peds
- Reservoir, no APL
26
______ is the entrance into the circle system where _______ is the exit
Common gas outlet = Entrance
| Scavenger system = Exit
27
What are 4 examples of classic LMAs?
1. Proseal
2. Supreme
3. I-gel
4. Fasttrach
- these are examples of mask on a stick that sit right outside the vocal cords
28
What are three examples of Pharyngeal Devices?
1. Combitube
2. Islip
3. King
- these are similar to the classic LMA but often used pre-hospital when desperate or difficult airway
- Designed to be placed blindly outside the vocal cords
29
What are 7 things to consider before placing an LMA
1. It has a flipped tip that prevents a proper seal
2. Positive pressure ventilation not recommended - but if you have to keep it less than 15cmH2O
- prone to atelectasis d/t no PEEP, but PEEP or Volume control ventilation can increase incident of air in belly = aspiration risk
3. Overinflation can cause tissue ischemia
4. Aspiration risk d/t not being a tight seal above the carina
5. 88 - 95% first time placement success rate
6. Spontaneous breathing gets best seal
7. Ideal for less than 2 hr use
- Also may not want to use if patient is overweight
30
What is the main consideration between using an oral & nasal airway?
Is the patient awake or not
- The awake patient has a gag reflex
- Too deep = obstruction of cords by pressing on epiglottis & then laryngospasm
- Too short = gagging d/t tickling of the uvula
31
How do you measure:
Oral Airway
LMA
Nasal Airway
1. Oral Airway = measure from angle of mandible or tragus of ear to lips
2. LMA = Based on kg weight with set inflation volumes
3. Nasopharyngeal Airway = tip of nose to tragus of ear
32
What are considerations for using a nasopharyngeal airway over an oral airway?
(3)
What is the most common complication of a nasal airway?
1. Marked overbite
2 Small mouth opening
3. Fragile teeth
- Bleeding is most common complication -
- Nose gets vasodilated & it is very vascular
= Should assess the patient if they can breathe better out of one side verses the other
33
What are 4 advantages of video laryngoscopes
1. Magnification of airway
2. Visualization of structures otherwise difficult to see
3. External monitor (if present) allows others to see & more readily assist & understand current airway situation
4. Recording capabilities
- Glidescope, McGrath. C-MAC, Airtraq
34
What is the Murphy’s eye?
It is the second port/opening on the ETT to allows gas movement if bevel is blocked
- or if there is a Right mainstem intubation
35
What are features on the ETT
Pilot balloon - inflates with the cuff but the location outside of the trachea serves as an indicator for the filling of air
Magill Curve = anatomical curvature of the ETT with a radius 140 mm
Blue longitudinal opaque line = so it will show up on a chest X-ray for placement
Transverse solid black lines = should be at the level of the cords, another placement identifier
36
ETT Adult Sizing
Should be based on patient ht & wt. d/t the glottis being the narrowest part of the airway
In general 7.0 F in women & 8.0 in men
- can have a 6.0 w/o significant increase in resistance/WOB/end Expiratory pressures
- & no change in FRC (functional residual capacity - expiration)
- If you go larger than a 7.0 you run the risk of trauma, sore throat & hoarseness
37
ETT Pediatric Sizing
ETT may be cuffed or uncuffed
Size = 16 + age ➗ 4
Depth = 3 x ETT size
38
What is a consequence of using Nitrous oxide (N2O) with an LMA/ETT?
The cuff is permeable and N2O can diffuse into cuff & cause cuff pressure to increase
- need to vent pressure over time to avoid ischemia
Also:
- not used often especially if its a long case
- enhances volatile agents
- makes me throw up = main reason its avoided
39
What is the benefit of a wire reinforced ETT
Kink resistant
- has more flexibility but hard to place - may need boogie or styles
- due to wire around edges it creates a smaller inner diameter
- Usually used in ENT cases b/c they want flexibility
40
What is an oral Rae?
ETT that is made to bring connections down the chin - allows circuit to lay on body
- Bend determines where the tube lies
- too long or too short can be a problem
- Used in craniotomies b/c Neuro does not want tube in their field
41
What is a Nasal Rae?
Used to bring connections up the forehead
- limited usage by size of nares and passages (assess breathing out of nostrils before use)
- Use a vasoconstrictor before placement
- May soften tube in warm water to make it more pliable and less traumatic placement
- Can’t use stylet
- Used in maxiofacial cases or dental restoration
42
What is the purpose of a Bougie
Used in difficult airway to use the tip to feel trachea rings then thread ETT over it and into the airway
43
What are most gas cylinder gauges calibrated at?
0 at atmospheric pressure
44
What is a Non-liquefied Compressed Gas
A gas that does not liquefy at room temperature regardless of pressure applied
1. Oxygen
2. Nitrogen
3. Air
4. Helium
45
What is a Liquefied Compressed Gas?
Gas that becomes liquid at ambient temperature and at pressures from 25 - 1500 psi
- Nitrous Oxide
- Carbon Dioxide
Maintains a constant pressure
- pressure on gauge not reflective of volume in cylinder
- full vs half full the pressure is exactly the same
46
Components of cylinder necks
Port
- point of gas exit (faces the machine)
- DO not screw retaining screw into port it will damage it & cause harm to the patient
Conical Depression
- This is what the retaining screw, screws into
- Holds the cylinder on the back of the anesthesia machine in the hanger yolk
Pressure Relief Valve
- Under the conical depression
- Allows cylinder to vent to atmosphere pressure if it becomes too high (warm temp, high altitude)
Handle
- opens & closes cylinder
- Turn is counter clockwise to open - making it a deliberate action
- Also called cylinder wrench
- Must have one for every machine
47
What does PISS stand for and what are the Locations
Pin Index Safety System
Holes on the cylinder neck that line up with pins on the yolk of the machine for safety of putting the right gas in the right spot
```
Oxygen = 2 & 5
Nitrous = 3 & 5
Air = 1 & 5
Entourage = 7 (this is 50% O2 & 50% N2O, used at the dentist office)
```
48
What are the cylinder PSI and L
Oxygen = 660L @ 2000 PSI
Nitrous = 1590 L @ 750 PSI
Carbon dioxide = 1590 L @ 838 PSI
Air = 625 L @ 1900 PSI
49
What is the pipeline system pressure
50 - 55 PSI
- this is in the intermittent pressure system - so it comes in at the working level of the machine
50
What is the most common pipeline alarm ?
Low pressure
| - decrease by 20% (40 psi)
51
What are 5 components of the Electrical system:
1. Master Switch (Mains Power)
- only the electrical outlets & battery charger to function
- Oxygen flush & O2 aux. flow meter (pneumatic)
2. Power failure indicator
- notifies of an AC power loss
3. Reserve power
- back up power on the machine
4. Electrical outlets
- loses function in power outage
5. Circuit Breakers
- has circuit breaker - no high frequency devices
52
What are the 3 levels of the Pneumatic System
High pressure system. = cylinder
Intermediate pressure system = machine
Low pressure system = atmospheric pressure = 1-50
Intro To Anesthesia
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