Airway Management Flashcards
(134 cards)
1
Q
Why Secure Airway?
A
o All ax > resp depression, relaxation, +/- loss of airway reflexes > patient prone to UAO
o Admin O2, volatile ax, other gases
o PPV, OLV
o Protect airway from aspiration (no cuff 100% leak proof)
o Low resistance, low dead space route for GE
o +/- protection from exposure to inhalants
2
Q
Downsides to ETT Intubation
A
o Potential for laryngeal, tracheal injury
o Improper use: inadvertent bronchial intubation, lrg amt of dead space if long tube
o Possible ^d mortality in cats? Not a good study > GP, cats not regularly intubated, only cats getting ETT systemically compromised
3
Q
Endotracheal tubes
A
- Impt factor in resistance, WOB - HP
- Internal diameter = narrowest diameter of equipment added to patient, site of greatest resistance
-Bypasses nasopharyngeal cavity, v anatomic dead space
4
Q
Wall Thickness of ETT
A
- Thicker walls = greater difference btw internal, outer diameters
- Very thick walled tubes: effectively decrease internal airway diameter
- Wall thickness to tube diameter greater in small tubes, increases resistance
5
Q
What determines size of ETT that can be placed in patient?
A
Outer diameter
6
Q
What is the potential consequence of a thin walled tube?
A
Prone to kinking, obstruction via external compression
7
Q
Ideal length of ETT
A
Incisors to thoracic inlet
Long tube will increase mechanical dead space, should trim machine end
decreased length will decrease resistance
8
Q
Why are translucent tubes preferred?
A
Visual inspection of blood, mucus, debris
9
Q
ETT Materials
A
PVC, silicone, red rubber, metal, latex
10
Q
Pros: PVC ETTs
A
Inexpensive, compatible with tissues
Stiff enough for intubation at room temp, soften at body temp
Less likely to kink than rubber tubes
Smooth inner surface
Transparent
11
Q
Cons: PVC ETTs
A
Disposable
12
Q
Pros: silicone ETT
A
Sterilized, reused
13
Q
Cons: silicone ETT
A
More expensive
14
Q
Pros: red rubber ETT
A
Cleaned, sterilized, reused
15
Q
Con: red rubber tube
A
Not transparent
Harden, become sticky overtime
More easily clogged by dried secretions
Do not soften at body temp
Risk of latex allergy
16
Q
What markings are required per ASTM?
A
- “Nasal,” “oral” or “Nasal/oral”
- ID: tube size, btw cuff and take off point of inflation tube for cuffed tubes, patient end for uncuffed
- OD for ETT <6.0
- Manufacturer
- Length, graduated markings showing distance in cm from patient end to allow depth of tube to be determined and monitored
- If disposable, single use only or do not reuse
- Radiopaque marker
17
Q
What does F29 on an ETT mean?
A
toxicity implants
18
Q
True/False: there are no standards for veterinary ETTs
A
True - should minimally have ID/OD
19
Q
How convert from French gauge/catheter scale?
A
Should reflect internal diameter of tube, often reflects outer diameter
mm = Fr/3.14
20
Q
Why is there a radiopaque marker at the end?
A
Black marker adjacent/near pilot balloon that indicates tube depth (people) -> cannot see once pas arytenoids
21
Q
Size of proximal machine connection in SA
A
15mm OD
22
Q
Size of LA large metal type that fits Bivona insert
A
22mm (Drager end)
23
Q
Size of LA silicone funnel type connector to LA wye piece
A
54mm OD
24
Q
What is the purpose of pediatric adaptors?
A
Smaller internal diameter, help improve accuracy of side stream, tidal gas sampling in smaller patients
25
Murphy ETT
o Murphy eye: hole in tube opposite of bevel
o Alternative route for gas flow should beveled end become occluded
Always on right side of tube
+/- Second eye above the bevel
Can become occluded/things get stuck in eye: stylets, bougies, fiberoptic scopes, suction
26
What direction does the Murphy ETT bevel face?
o Bevel always faces LEFT when viewed from concave aspect, with angle of bevel = 30*
27
What is the size of the Magill curve on a Murphy ETT?
anatomic curvature ~140 +/- 20mm on PVC tubes
At body temp or when placed in warm water, curve will soften so lose () angle
28
Magill ETT
o Similar to Murphy, but NO Murphy eye!
o Allows cuff to be placed closer to tip, s risk of inadvertent bronchial intubation
29
Cole ETT
thin portion in trachea, thicker portion occludes larynx
o Do not produce same degree of airway security
o Used for very small patients, patients with complete tracheal rings ie **birds, turtles**
o Resistance less than that of a comparable tube of constant lumen
30
Safe-Seal ETT
o Uncuffed, self-sealing ETT for veterinary market (no Murphy eye or inflatable cuff)
o Tube designed with series of flexible flanges at patient end of ETT that deform to contours of trachea . form seal against tracheal wall > eliminates need to inflate cuff
o Limited number of sizes
o Tube efficacy not evaluated
31
Cuffs
o Purpose: provide seal btw tube/trachea, center tube in trachea
Inflation tube + pilot balloon + inflation valve
32
Advantages of a cuff
Improved accuracy of monitoring end-tidal gases, compliance, O2 consumption
decreased risk aspiration
Ability to use high inflation pressures, low FGFs
Less OR pollution
decreased fire risk
Fewer tube changes
decreased risk spread of infectious droplets vs uncuffed?
33
Low vol, high pressure cuff
- Small diameter at rest, low residual volume
-Requires high intracuff pressure to achieve seal with trachea
- **Does not bear consistent relationship to tracheal wall pressure**
34
Low vol, high pressure cuff relationship to trachea
-Small area of contact with tracheal wall, **distends/deforms trachea to circular shape**
-Most of pressure inside cuff used to overcome poor compliance of cuff: **cuff pressure~pressure created by elastic recoil of cuff**
-Intracuff pressure doesn’t change when trachea contacted
35
Advantages low vol, high pressure cuff
* Better visibility during intubation DT streamlined cuff
* Better protection of aspiration
* Usually reusable, less expensive
* Humans: lower incidence of sore throat
36
Disadvantages low vol, high pressure cuff
* **More difficult to estimate tracheal wall pressure**, likely well above mucosal perfusion pressure
* Risk of ischemic damage to tracheal wall with prolonged use
* **Intracuff pressure, lateral pressure on tracheal wall increases sharply as increments of air added**
37
Use of low vol, high pressure cuffs
Impt to check for leaks approx 10’ after intubation: softening of cuff material at body temp, volume necessary for occlusion varies with muscle tone
38
High vol, low pressure cuffs
-Preferred: may help reduce tracheal damage from cuff overinflation
**Pressure exerted by cuff similar to intracuff pressure**
Thin, compliant wall allows seal with trachea to be achieved w/o stretching tracheal wall
Cuff inflated: first touches trachea at widest part of cuff, area becomes larger as cuff begins to inflate, cuff adapts itself to shape of tracheal surface
If cuff inflation continued, area in contact with cuff subject to increasing pressure > trachea distorted
39
High Vol, Low pressure cuff: variations during SpV
airway, cuff pressure negative during inspire, positive during expire
40
High vol, low pressure cuff: variations during CMV
airway pressure exceeds intracuff pressure, positive pressure will be applied to lower face of cuff if cuff wall pliable, unable to resist pressure > will be deformed into cone shape as distal portion is compressed, proximal portion distended
* Air in cuff will be compressed until intracuff pressure = airway pressure
41
High vol, low pressure cuff: exhalation
intra cuff pressure will decrease until resting pressure is reached
42
High vol, low pressure cuff: advantages
* As long as cuff wall not stretched, intracuff pressure closely approximates pressure on tracheal wall > possible to measure, regulate pressure exerted on tracheal mucosa
* If used properly, risk of significant cuff-induced complications with prolonged use decreases
* Easy to pass esoph stethoscopes, temp probes, etc around
43
High vol, low pressure cuff: disadvantages
* Can obscure view of tube tip, larynx DT bulkier cuff, can be problematic in smaller patients
* Cuff more likely to be torn
* Greater likelihood that dislodged???
* Humans: higher incidence of sore throat
* May not fully protect against aspiration, even at cuff pressures as high as 60 cm H2O
o Less leaking if no folds, CPAP, PEEP, PSV
* WILL NOT PREVENT HIGH PRESSURES FROM BEING EXERTED ON TRACHEAL WALL
o ANY CUFF CAN BE OVERFILLED, VOL/PRESSURE CAN DECREASE DURING USE
o Ex: N2O will diffuse into cuff, added volume will increase pressure on tracheal mucosa
44
Other types of cuff
Foam Cuf
Lanz Cuff
Jorvet
45
Foam Cuff
expansion determines pressure on tracheal wall, more foam expansion less pressure, pressure inside cuff will follow approx airway pressure during vent cycle
46
How seal foam cuff
o To seal: open inflation tube to atmosphere, allow cuff to fill with air
o Ability to remove 2-3mL air from small cuff, 5-6mL from larger cuffs and maintain seal usually signifies cuff:tracheal wall pressure ratio will allow adequate mucosal perfusion
47
Lanz Cuff
-pressure-regulating valve, eliminates need to measure cuff pressure, effective in keeping lateral tracheal wall pressure low and preventing increases in cuff pressure DT N2O
o To seal: add air until seal achieved during peak inspiration
48
What is a Jorvet cuff?
The weird baffles
49
What is the typical pressure on the lateral tracheal wall at the end of expiration per DD?
25-34 cm H2O (20-30)
* If high peak inflation pressures, will need higher cuff pressure to prevent leaks (minimum occlusion pressure) --> increases risk tracheal injury
50
At what point will tracheal mucosa become slightly pale with visible, pulsatile arterioles?
30 cmH2O
51
What are factors that can change intracuff pressure?
--N2O: increase varies directly with partial pressure of N2O, permeability of cuff wall, time
o Slowed by heated humidification
--Pressures lower during hypothermic bypass
--Increased pressures seen with nearby surgical procedures, increases in altitude, diffusion of oxygen into cuff, changes in head position away from neutral, coughing, straining, changes in muscle tone
o Not seen with foam-filled cuffs
52
At what pressure is capillary flow impeded, leading to ischemia?
48cm H2O
53
Consequences of tracheal rupture?
Pneumothorax
Pneumediastinum
SQ emphysema
54
At what pressure is there increased risk of aspiration?
<25cm H2O, increased risk aspiration
55
Three methods to check cuff pressure
* Cuff monitor: high volume, low pressure cuffs - low pressure manometer attached to pilot balloon of cuff
* Leak test: Inflate cuff with air, water, sponge until leak no longer audible when maintaining airway pressures of 20-30 cm H20
* Modified human products/Tru-Cuff syringes
56
Pilot Balloon
most have self-seal syringe activated system (spring loaded one way valve), some require clamp
External diameter of pilot balloon line <2.5mm, attached to ETT at angle
57
Combitube
Emergent intubation in field setting with people
No laryngoscope
Place tube, inflate distal cuff -> if no CO2, inflate proximal cuff to protect airway, functions as LMA
Described in dogs, not often used
58
King Airway
NOT A COMBITUBE
Distal tube goes into esophagus
No distal lumen
Supraglottic airway device, ventilates like combitube
59
Laser Resistant tubes: Hunker Tube
designed for jet ventilation – compatible with CO2, neodymium-yttrium aluminum garnet (Nd-YAG), argon laser, OD 3mm
60
Laser Resistance Tubes: Laser Shield II tube
inner aluminum wrap, outer Teflon coating
* CO2, potassium-titanyl-phosphate (KTP) lasers
* Cuff not laser resistant, contains methylene blue
61
Laser Resistance Tubes: Laser-Flex Tracheal Tube
* Stainless steel with smooth plastic surface, matte finish to reflect beam
* CO2, KTP lasers
* Adult version: two PVC cuffs, PVC tip with Murphy eye
* Fill cuffs with saline colored with methylene blue
* Still, rough surface, difficult to intubate quickly (double cuff), large external diameter, less likely to reflect CO2 laser radiation than other tubes
62
Laser Resistant Tube: Norton Tube
* Reusable, flexible, spiral-wound metal tube with stainless steel connector and thick walls
* Tube exterior: matte finish to reflection of laser beam
* CO2, KTP, Nd-YAG
* Uncuffed, can be added
* Disadvantages: coils not air-tight, angulation leads to large leak, rough outer surface, sharp edges – tissue damage, large external diameter, stiff, requires special ventilation techniques
63
Laser Resistance Tubes: Bivona Fome-Cuf Laser Tube
* Aluminum, silicone spiral with silicone covering
* Self-inflating cuff: polyurethane foam sponge, use saline intraop
* Inflation tube runs along exterior of tube, colored black so that position away when laser in use
* Marketed for use with CO2, poorly resistant to all lasers
64
Laser Resistant Tubes: Lasertubus
* White rubber, tube within a tube: if outer cuff (saline, water) perforated by laser, trachea still sealed by inner cuff (air)
* High pressure cuff
* Shaft above cuff covered by corrugated silver foil, which is covered by Merocel sponge that should be moistened before use
* Argon, CO2, Nd-YAG
65
Merocel Laser Guard
two-layered sheet of synthetic surgical sponge, adhesive-backed corrugated silver foil
o PVC, rubber tubes only
o When wet, sponge/reflective foil act like a heat sink disperse argon, CO2, Nd-YAG, KTP laser beams
66
If you don't have a specialized tube for laser sx, now what?
- Fill ETT balloon with water instead of saline
- Cover with damp gauzes and KEEP MOIST
(most in lasers section)
67
Guarded/Armored tube
Contain metal or nylon spiral wire covered by rubber, PVC, silicone to prevent kinking
Useful in situations where tube likely to compressed, kink ie extreme flexion of head or compression of trachea
* Kinking: airway obstruction, d resistance
Thicker OD, smaller ID: increased resistance to flow
68
Advantages to guarded tube
less likely to kink if tube bent or head/neck flexed, may pass more easily over fiberscope
69
Disadvantages to a guarded tube
NO MURPHY EYE
cannot be shortened, forceps or stylet sometimes needed for intubation, should not be resterilzed, elastic recoil force may increase tendency of accidental extubation
70
Ring-Adair-Elwin Tube
Preformed bend that may be temporarily straightened during intubation
Cuffed, uncuffed; nasal, oral
Used for head and neck surgery
Diameter increased, -> length, distance from distal tip to curve also increased
71
Ring-Adair-Elwin Tube PO vs Nasal parts
* PO: external portion bent at an acute angle, rests on patient’s chin with connector over patient chest when in place
* Nasal: opposite curve so that outer portion directed over patient’s forehead to reduce pressure on nares
72
Laryngotomy tube
J at patient end to insert into tracheostomy site
73
Flex Tubes
Endoflex: anterior larynx in peopke, tube can flex at cuff
Parker Flex-Tip Tube: hooded curved tapered tip with Murphy eyes on L, R, easier to advance over scope or intubating catheter
74
Tubes with Extra Lumens
Useful for respiratory gas sampling, suctioning, airway pressure monitoring, fluid/drug injection, jet ventilations
Disadvantages: secretions, blood or moisture can obstruct extra lumen; sampling tube must be securely stabilized to minimize tension on tube, moisture can enter gas lumen, cause problems with gas monitor
75
Nerve Integrity monitoring
EMG reinforced tracheal tube
Monitor RLN electromyogram (EMG) activity during sx
Wire-reinforced, four stainless steel electrodes above cuff with electrodes connected to a monitor
76
Complications during intubation
hematomas, contusions, puncture wounds, tracheal rupture, fractures, arytenoid cartilage dislocation, perforation of any structures in area
o Sore throat, hoarseness, upper airway edema, vocal cord dysfunction, ulcerations
o Neurological injuries: trigeminal, lingual, buccal, hypoglossal
77
Confirmation of correct placement into trachea
o Most reliable methods: direct visualization of tube passing btw vocal cords, capnometry, auscultation: both sides of chest (gurgling sounds – esoph), breathing system auscultation, fiberoptic visualization, pressure/flow-volume loops
ASA standard: confirm correct placement into trachea with capnometry
False negative: severe bronchospasm, cardiac arrest, no pulmonary blood flow (PE, one way obstruction in tracheal tube)
78
Other less reliable methods
feel of reservoir bag, chest wall motion, epigastric distention, moisture accumulation in trachea, gastric contents in tracheal tube, CXR, oxygenation, palpation, cuff inflation
79
Challenges of using chest wall movement to confirm placement into trachea
following conditions could stimulate tracheal intubation during esoph intubation: patients with low lung volume, obese patients, low chest wall compliance, abdominal resp
80
Strategies to troubleshoot leaking cuff
o Use pharyngeal packing to control leak, increase FGF to compensate for leak
o Fill cuff with mixture of lidocaine, saline or use saline infusion
o Continuous gas infusion into inflation tube
o Supraglottic device
o Replace ETT
81
Causes of Obstructions
Biting
kinking
materials in tube lumen (secretions, gastric contents, blood, etc)
occlusion of spiral end tube (NO MURPHY EYE) cuff herniation/bevel displacement
external compression or displacement (aorta, enlarged thyroid, etc)
defective connector
Change in body position
82
Dx: obstructions
decreased compliance or expiratory flow
increase in difference btw peak and plateau pressure with VCV
decrease VT with PCV
Wheezing
PV loops
Spontaneous ventilation: paradoxical chest movements
Capnograph: increased slope phase III, large angle – “shark fin”
83
Consequences of obstructions
o High negative intrathoracic pressure NCPE
o Permits inhalation, prevents exhalation (ball-valve obstruction): circulatory collapse, barotrauma
84
Stylets
Designed to fit inside ETT, change shape of ETT to facilitate intubation
Check patency of ETT
Means to limit depth stylet inserted into ETT
Enough malleability to shape can change easily, will yield if pressed against soft tissues, rigid enough to maintain shape
85
Bougies
Soft, flexible, cannot really shape to fit ETT – long, straight
Fabricated from polyester base with resin coating
Reusable
86
Cook Airway Exchange Catheters
More flexible, longer than a bougie
Hollow -> proximal connections allow admin of O2, jet ventilation, connection to ETCO2 or suctioning
Must be long enough so that tube can be completely removed without catheter pulled
into trachea, stiff enough so won’t kink
87
Laryngoscopes
* Aid tracheal intubation, oropharyngeal evaluation/airway exam
* Plastic with fixed blade, stainless steel with interchangeable blades of different sizes
* Handle with lighted blade - No clear advantage over lighting system
88
Fiber Optic Laryngoscope Blade
Bulb is in blade handle, blade has optical fiber -> communicate
* Halogen lamp bulb
Can be more reliable, less likely to have bulb fall off inside patient
ASTM standards: green mark
89
Bulb in Blade
Electrical (metallic) contact, has to be clean and in good working order
Overtime can erode, less consistent than fiber optic
90
Video laryngoscopy
usually used for teaching, small direct video laryngoscopy with bronchoscope
91
Other laryngoscope modifications
changes for very small, very large patients; magnification; cheek spreaders for small ruminants or rodents
92
Blades
000-5
o Tongue = main shaft, base attaches to handle
o Tip = beak
o Flange = projects off side of tongue, connected by web – guide instrumentation, deflect tissues from line of vision
o Blade flange typically on right side of blade when viewing from top
Optimal laryngeal visualization when intubating in dorsal, laryngoscope held in L hand with blade downward (inverted) and tube in R hand with concave aspect pointing up
93
Complications of Direct Laryngoscopy
dental injury
cervical spinal cord injury if aggressive head positioning
hematoma/lacerations to any oral/airway structures
shock/burn if light left on
swallowing/aspirating FB (loose light)
94
Laryngeal Mask Airways
o Human products, adapted for veterinary use
o Optimized specifically for orolaryngeal/pharyngeal anatomy of humans may not conform well to varied anatomy, patient size, species, breeds of veterinary patients
o Inappropriate SGAD +/- patient selection may lead to placement difficulties/failures, damage to tissues of oropharyngeal region, +/- improper patency of airway
95
Advantages of LMAs
o Do not require laryngoscope, do not enter larynx or trachea
Possibly faster, easier to place in some species
+/- less ax required to place
o Tube connected to elliptical mask with inflatable outer edge when placed/inflated correctly, form seal around glottis
Can PPV
Not assoc with greater leakage ax gases
96
Wiederstein and Moens 2008 (VAA):
clinically optimal position, seal around larynx adequate for manual PIP 10cmH2O 63.3% dogs, suboptimal positioning/inability to ventil in 36.7%
97
V-gels
veterinary specific product for cats, rabbits (and now dogs)
98
Why perform OLV
* Thoracoscopy, control of contamination, hemorrhage, unilateral pathology
99
Three MOA for OLV
1. double lumen tube
2. Bronchial blocker
3. Standard but long ETT
100
What are three DLT options?
Robertshaw, Carlens, White
101
Double Lumen Tubes
Two single lumen tubes bonded together, angled tip to facilitate placement into bronchus
Two elliptical cuffs: trachea, bronchus (different colors)
Allows independent ventilation of each lung or together without moving, replacing tube
Requires disconnection/reconnection, appropriate adapter for task
102
R vs L sided tubes in dogs?
placement uncertainty in dogs -> R cranial LL branches more proximally than in people, failure of complete hemithorax isolation
103
How are DLT sized?
French scale: 26-41 Fr
decreases lumen size -> increases resistance to breathing, overcome by PPV
104
Size limitations on use of DLT
Designed for humans so 5-20kg
105
Problems with the Carlens, White Tubes?
carinal hook designed to aid in proper placement, prevent movement after positioning
May hinder ETT placement
Ensure does not catch on tissues, structures
106
Which is the DLT of choice for canine patients?
o ***L ROBERTSHAW***
107
How confirm correct placement of DLT
endoscopy – direct visualization, thorascopic-assisted technique, lung sounds bilaterally following ventilation of both sides
Blind: high failure rate
Prone to movement, can prolapse into trachea -> airway obstruction
108
Bronchial Blockers
Very adaptable over wider range patient sizes, not as anatomically specific
Long catheters tipped with cuff/balloon
Usually blue to differentiate from ETTs
o Used coaxially with standard ETT, swivel adapter – ports for passing blocker, scope, etc
Length of bronchial blocker limited, may not be sufficiently long for larger patients
109
Placement of bronchial blockers
***fiber optic assisted*** direct visualization for correct placement
Used to isolate single lung lobe in addition to entire hemithorax
Once in correct place via direct manipulation of proximal portion or guide wire into bronchus, bronchial blocker channel opened lung collapses
***Open channel: CPAP, oxygen insufflation, suction***
***Right bronchus challenging, proximal branching of cranial lobe***
110
Downsides of bronchial blockers?
May not be sufficiently long enough for larger patients
Independent lung ventilation not possible without withdrawing, replacing in contralateral bronchus
Prolapse of bronchial blocker into trachea = complete airway obstruction
Placed proximally in bronchus +/- tube/bronchial blocker withdrawn inadvertently when moving or manipulating the patient
111
What can be used as a bronchial blocker?
Any Balloon catheter (Fogarty, Foley)
112
Standard but long ETT for OLV
o Least desirable: less direct control for making changes in non-intubated lung
o No specialized equipment required
o Easy to perform
113
Risks of OLV
Pulmonary reexpansion injury
VQ mismatch
anatomical concerns/difficult placement
114
Nasotracheal intubation
o Procedures involving oral cavity, sedated conscious animals that will not tolerate ETT but require O2, induction of GA in foals/calves
o Performed in many species: reported in foals, calves, horses, camelids, rabbits, kangaroo
115
Tube used for NTT
minimal curvature/straight, thin walled for larger ID, LV/HP cuff better for passage bc less bulky, HV/LP cuff better for longer periods of ax
Will be smaller than orotracheal tube, increased resistance
116
How NTT
o Extend head and neck to facilitate passage, lube *ventral nasal meatus*
o Confirmation by inflated “bulb syringe,” auscultation of lung fields, capnography
o Careful extubation to avoid nasal hemorrhage if shake head
Main complication: nasal hemorrhage
117
Wire Guided Tube Techniques
o Direct visualization of laryngeal opening not possible or obscured
o OTW technique or the Campoy feed off
o Blunt end to avoid tracheal damage
118
Tube Exchangers
o Failing cuff, placement of sterile tube, alternative tube size/length required
o Depending on size of patient, standard commercially available human tube exchangers can be used
o Be sure to dc inhalant ax if using prior to exchange, have injectable boluses ready if needed
119
Endoscopic Guided
o Abnormal anatomy, dz processes involving pharynx, head, neck or if challenging to intubate with direct laryngoscopy
o Flexible or rigid
o Placed within ETT to guide intubation directly or passed orally beside ETT to guide correct placement visually
o Also used for nasotracheal intubation
Horses/other LA with abnormal oropharyngeal, laryngeal +/- nasal anatomy where direct laryngoscopy impossible
120
Retrograde Intubation
o When direct visualization of glottis impossible
o Evaluated in camelids, mice
o Needle introduced through ventral neck btw tracheal rings, wire passed rostrally into larynx/pharynx until can be used as OTW technique to pass ETT
Ensure cuff caudal to needle puncture site to avoid forcing gas subcutaneously or into mediastinum during PPV
121
Complications of retrograde intubation
SQ emphysema, pneumothorax
122
Tracheostomy
o Surgeries involving oropharynx, traditional intubation impossible, patient requires tracheostomy post-operatively, emergent upper airway obstruction
o Simple to intubate through tracheostomy
Can be difficult in patients with very small-diameter tracheas, those with very thickened/calcified tracheal rings
123
Trach Tubes
generally shorter with acute angle, standard 15mm connection adapter, smaller sizes often do not have a cuff
o If not cleaned regularly, can become obstructed by mucus that dries within lumen
124
Risks, complications of tracheostomies
NOT TOLERATED WELL IN CATS
infection, granulomas, tracheal stricture, cartilage damage, hemorrhage, pneumothorax, subcutaneous edema, tracheocutaneous/tracheoesophageal fistula, aspiration, dysphagia, tracheal malacia
125
Tracheostomy Technique
Ventral neck
Ventral midline cutaneous incision 2-3cm cd to cricoid cartilage
Blunt dissection: separate sternohyoid m along fascial plane until trachea visualized
Transverse tracheotomy incision through annular ligament btw tracheal rings, do not incise >50% circumference
Stay sutures cr, cd to incision traction insert trach tube
126
Rhino Technique
o Similar to traditional tracheostomy
o Less surgical manipulation, no difference according to literature
Higher risk of not cannulating trachea, causing SQ emphysema, fracturing tracheal rings
Not faster (Pardo et al 2019)
o Modified Seldinger Technique: place J wire facing lungs, feed multiple dilators over J wire increase size of entry into trachea
127
Lateral Pharyngotomy
o Alternative to tracheostomy for sx procedures of mandible, maxilla, oral cavity
o Slightly less invasive than tracheostomy
o Skin incision near angle of the mandible adaptor removed machine end of tube pulled through the pharynx/skin incision reconnected
o Dentistry, similar to E tube placement
128
Why deliver oxygen
o PaO2 and promote delivery of oxygen to tissues
o Room air, PaO2 <80mmHg indicate potential for hypoxemia, <60mmHg indicates need for supplemental oxygen
o PaO2 ~ 500 x FIO2 if no major abnormalities
o Supplemental oxygen can correct hypoxemia with diffusion, VQ mismatch or hypoventilation, but may not significantly improve shunt
o Monitor improvement by patient clinical response, measuring FIO2, monitoring PaO2, SaO2, SpO2
129
Methods for oxygen delivery
o Mask Delivery: before induction, patients in resp distress
o Nasal Insufflation: delivery of oxygen at relatively high flow rates
o Tracheal Insufflation: Patients suffering from upper airway obstruction
o Oxygen Cages: small animals, regulate oxygen, humidity, temperature, and eliminate CO2
130
Flow By Oxygen
~FiO2 25-40%, FR 0.5-5L/min
131
Face Mask
~FiO2 35-60%, FR 2-8L/min
132
Nasal Insufflation
~FiO2 30-70%, FR 100-150mL/kg/min
133
Tracheal Insufflation
~FiO2 40-60%, FR 50mL/kg/min
134
Oxygen Cages
~FiO2 25-50%, FR variable
