Airway Management

VP
AIRWAY MANAGEMENT
1. Anatomy
a. Upper airway: pharynx, nose, mouth, larynx,
trachea, main-stem bronchi
b. There are two openings to the human airway:
the nose (leads to nasopharynx) and the
mouth (leads to oropharynx). They are
separated anteriorly by the palate
c. Pharynx is a U-shaped fibromuscular structure
that extends from the base of the skull to the
cricoid cartilage at the entrance to the
esophagus.
d. Nasopharynx is separated from the
oropharynx by an imaginary plane that
extends posteriorly
e. The epiglottis functionally separates the
oropharynx from the laryngopharynx and prevents aspiration by covering the glottis
when swallowing.
f. The larynx is a cargilaginous skeleton held by ligaments and muscles. It is composed
of nine cartilages: thyroid (shields conus elasticus which forms vocal cord), cricoid,
epiglottic, and (in pairs) arytenoid, corniculate, and cuneiform.
g. Sensory supply:
i. Mucous membranes of nose: CN V.1 anteriorly and V.2 posteriorly
ii. Superior and inferior surface of hard and soft palate: palatine nerves
iii. Nasal mucosa: CN I
iv. Anterior 2/3 of tongue: CN V.3 with branches of CN VII, Posterior 1/3 of
tongue: CN IX
v. Superior laryngeal branch of vagus nerve divides into:
1. External (motor) nerve (cricothyroid muscle)
2. Internal (sensory) laryngeal nerve
Provides sensory supply to the larynx between epiglottis and vocal cords
vi. Recurrent laryngeal nerve: innervates larynx below the vocal cords and
trachea
1. Innervates the muscles of larynx except the cricothyroid muscle
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h. Effects of laryngeal nerve injuries:
i. Unilateral denervation of cricothyroid muscle: very subtle clinical findings
ii. Bilateral palsy of superior laryngeal nerve: hoarseness, airway still fine
iii. Unilateral paralysis of recurrent laryngeal nerve: paralysis of ipsilateral vocal
cord -> deterioration of voice quality
iv. Assuming intact superior laryngeal nerve, acute bilateral recurrent laryngeal
nerve palsy -> stridor and respiratory distress because of tension of
cricothyroid muscle. Chronic bilateral recurrent laryngeal nerve loss rarely
provide airway problems due to compensatory mechanisms (such as
atrophy of laryngeal musculature)
v. Bilateral injury to vagus nerve affects superior and recurrent laryngeal
nerves -> flaccid midpositioned vocal cords with impairment of phonation
and airway control is of no problem
i. Blood supply to the larynx:
i. Branches of the thyroid
arteries
ii. Cricothyroid artery from
the superior thyroid artery
j. Trachea begins beneath the cricoid
cartilage and extends to the carina
-> anteriorly the trachea consists of
cartilaginous rings, posteriorly it is
membranous.
2. Routine airway management:
a. Airway assessment
b. Preparation and equipment check
c. Patient positioning
d. Preoxygenation
e. Bag and Mask Ventilation (BMV)
f. Intubation (if indicated)
g. Confirmation of endotracheal tube placement
h. Intraoperative management and troubleshooting
i. Extubation
A. Airway Assessment
a. First step in successful airway management
b. Assessments include:
i. Mouth opening: incisor distance of 3cm or greater is desirable in
adult
ii. Upper lip bite test: lower teeth are brought in front of the upper
teeth. This estimates the range of motion of the TMJ
iii. Mallampati classification: examines the size of the tongue in relation
to oral cavity. The greater the tongue obstruction the more difficult
intubation may be.
1. Class 1: Entire palatal arch including the bilateral faucial
pillars are visible down to their bases
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2. Class 2: Upper part of the faucial pillars and most of the
uvula are visible
3. Class 3: Only the soft and hard palates are visible
4. Class 4: Only the hard palate is visible
iv. Thyromental distance: Distance between mentum and the superior
thyroid notch. Distance greater than 3 fingerbreadths is desirable
v. Neck circumference: greater than 27 inches is suggestive of
difficulties in visualization of the glottic opening
vi. Patient with morbid obesity: some may present with redundant
pharyngeal tissue and increased neck circumference
B. Equipment:
a. The following equipment is routinely needed in airway mangement
situations:
i. Oxygen source
ii. BMV capability
iii. Laryngoscopes (direct and video)
iv. Several endotracheal tubes of different sizes
v. Other (not ETT) airway devices (oral, nasal airways)
vi. Suction
vii. Oximetry and CO2 detection
viii. Stethoscope
ix. Tape
x. Blood pressure and electrocardiography monitors
xi. IV access
b. Oral and nasal airways:
i. Loss of upper airway muscle tone in anesthetized patients allow the
tongue and epiglottis to fall back against the posterior wall of the
pharynx
ii. Repositioning the head or jaw thrust is preferred technique for
opening the airway
iii. Awake or lightly anesthetized patient with intact laryngeal reflex
may cough or even develop laryngospasm during airway insertion!
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iv. Adult oral airways:
1. Small (80mm, Guedel No. 3)
2. Medium (90mm, Guedel No. 4)
3. Large (100mm, Guedel No. 5)
v. Length of nasal airway can be estimated as the distance from nares
to the meatus of the ear, and should be 2-4cm longer than oral
airways and lubricated.
c. Face mask design and technique:
i. The rim of the mask is contoured and conforms to a variety of facial
features
ii. Effective mask ventilation requires gas-tight mask fit and a patent
airway.
iii. If the mask is held with the left
hand, the right hand can be used
to generate positive pressure
ventilation by squeezing the bag.
Mask is held onto the face by
thumb and index finger while the
middle and ring finger grasp the
bony mandible. Little finger is
placed under the angle of the jaw
and is used to thurst the jaw
anteriorly.
iv. In difficult situations, two hands
may be needed to provide
adequate jaw thrust and mask seal
-> needs assistant to squeeze the
bag or machine’s ventilator.
Obstruction during expiration can
be due to:
1. Excessive downward
pressure from mask ->
decrease pressure on
mask
2. Ball-valve effect of the jaw
thrust -> releasing jaw thrust during the phase of respiratory
cycle
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v. Positive pressure ventilation using mask should be limited to
20cmH2O to prevent stomach inflation
vi. Mask ventilation for long periods of time -> pressure injury to
branches of trigeminal or facial nerves. And if face mask and mask
straps are to be used for extended periods -> position should be
changed to prevent injury
vii. Tape the eye to minimize risk of corneal abrasions!
C. Positioning:
a. Relative alignment of oral and pharyngeal axis is achieved by having the
patient in sniffing position
b. If cervical spine pathology is suspected -> head must bekept in neutral
position during all airway manipulations
c. Patients with morbid obesity should be positioned on a 30 degree upward
ramp, as functional residual capacity of obese patients decreases with
supine position -> more rapid deoxygenation if ventilation is impaired.
D. Preoxygenation:
a. Preoxygenation with face mask oxygen should procede all airway
mangement interventions
b. O2 is delivered by masks for several minutes before anesthetic induction ->
functional residual capacity (patient’s O2 reserve) is purged of nitrogen.
c. Up to 90% of normal FRC of 2L following preoxygenation is filled with
oxygen -> 5-8 minute oxygen reserve.
d. Increasing duration of apnea without desaturation improves safety if
ventilation following anesthetic induction is delayed.
e. Condition that increase O2 demand (sepsis, pregnancy) and decreased FRC
(morbid obesity, pregnancy) -> reduce apneic period before desaturation
ensues
E. Bag and Mask ventilation:
a. First step in aiway management except patients undergoing rapid sequence
intubation
b. BMV is avoided to prevent stomach inflation -> potential for aspiration of
gastric contents in nonfasted patients
c. Supraglottic airway devices: consists of a tube connected to respiratory
circuit or breathing bag. Common side effect is sore throat with injuries to
lingual, hypoglossal, and recurrent laryngeal nerve has been reported.
i. Laryngeal mask airway:
1. Helpful as life-saving temporizing measure in patients with
difficult airways (cannot be ventilated or intubated)
2. Wide bore tube that connects to breathing circuit (15mm
connector) and distal end is attached to elliptical cuff that
can be inflated through pilot tube which is lubricated and
inserted blindly to hypopharynx to perform seal around the
entrance of larynx.
3. Requires anesthetic depth and muscle relaxation slightly
higher than required for insertion of an oral airway
4. Ideally positioned cuff:
a. Batas superior: base of tongue
b. Batas lateral: pyriform sinus
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c. Batas inferior: esophageal sphincter
If esophagus lies within the rim of the cuff -> gastric
distension and regurgitation is possible
Protects larynx from pharyngeal secretion but not gastric
regurgitation
Must remain in place until patient has regained airway
reflexes -> coughing, mouth opening on command
Relative contraindication: pharyngeal pathology (abscess),
pharyngeal obstruction, full stomach (pregnancy, hiatal
hernia), low pulmonary compliance (restrictive airway
disease) requiring inspiratory pressure >30cmH20
Avoided in patients with: bronchospasm, high airway
resistance
Insertion can be performed under local anesthesia and
bilateral superior laryngeal nerve blocks if airway needs to
be secured and patient is still awake.
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11. Variations in LMA include:
a. ProSeal LMA: permits passage of gastric tube to
decompress stomach
b. I-Gel: gel occluder rather than inflatable cuff
c. Fastrach intubation LMA: facilitate ETT through LMA
d. LMA Ctrach: incorporates camera to facilitate ETT
ii. Esophageal-Tracheal combitube:
1. Consists of two fused tubes, each with a 15mm connector
on proximal end
a. Longer blue tube has an occluded distal tip with side
perforations -> forces gas to exit
b. Shorter clear tube -> open tip, no side perforation
2. Usually inserted blindly through the mouth until two black
rings lie between the upper and lower teeth.
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3. Has two inflatable cuffs, 100mL proximal cuff and 15mL
distal cuff which should be fully inflated after placement.
a. Distal lumen lie in
esophagus 95% of the
time -> ventilation
through blue tube will
force gas to go
sideways through the
perforations
b. Shorter clear tube:
used for gastric
decompression
c. If it enters the trachea, ventilation through the clear
tube will direct gas into the trachea
iii. King Laryngeal Tube:
1. Tube with a small esophageal
balloon and larger balloon for
placement in hypopharynx
which inflates through one
inflation line
2. Lungs are inflated from air
that exits from two balloons
3. If ventilation is difficult -> LT
is likely inserted too deep ->
slightly withdrawing the
device until compliance
improves ameliorates the situation
F. Endotracheal intubation: employed for conduction of GA and facilitate the ventilator
management of the critically ill
a. Tracheal tubes:
i. Most commonly made from polyvinyl chloride
ii. Shape and rigidity can be altered by inserting a stylet
iii. Resistance to airflow depends primarily on tube diameter but also
by tube length and curvature. Size is usually designated in
milimeters of internal diameter or the FRENCH STYLE (milimeters of
external diameter dikali tiga)
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iv. Dilemma pemilihan tube diameter: maxinizing airflow with larger
size vs minimizing trauma with smaller size
v. Most adult TT have cuff inflation system which includes:
1. Valve: prevents air loss after cuff inflation
2. Pilot balloon: provides gross indication of cuff inflation
3. Inflating tube: connects valve to the cuff and is incorporated
into the tube’s wall.
4. Cuff: permits positive-pressure ventilation and reduce
likelihood of aspiration by creating tracheal seal. Uncuffed
tubes are often used in infants and young children to
minimize the risk of pressure injury and postintubation
croup
vi. There are two major types of cuffs:
1. High pressure (low volume): associated with more ischemic
damage to tracheal mucosa, less suitable for intubation of
long duration
2. Low pressure (high volume): increase likelihood of sore
throat (larger mucosal contact area), aspiration,
spontaneous extubation, difficult insertion (floppy cuff) ->
generally employed due to lower incidence of mucosal
damage
vii. Cuff pressure depends on several factors:
1. Inflation volume
2. Diameter of cuff in relation to trachea
3. Tracheal and cuff compliance
4. Intrathoracic pressure (cuff pressure increase with
coughing)
5. May increase during GA from diffusion of NO from trachea
mucosa into the TT cuff
viii. Specialized tubes:
1. Flexible tubes
2. Spiral-wound
3. Wire-reinforced (armored): resist kinking and useful in head
and neck surgery
4. Micro-laryngeal tubes
5. Double-lumen ETT (facilitate lung isolation and one-lung
ventilation)
6. ETT equipped with bronchial blockers (facilitate lung
isolation and one-lung ventilation)
7. Metal tubes: for laser airway surgery
8. Preformed curved tubes for nasal and oral intubation in
head and neck surgery
b. Laryngoscopes:
i. Instrument to examine the larynx and facilitate intubation of the
trachea, with the Macintosh and Miller blades being most popular
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ii. Types include:
1. Video laryngoscope:
a. Have either a video chip (DCI, GlideScope, McGrath,
Airway) or lens / mirror (Airtraq) at the end of the
tip of intubation blade
b. Proves advantageous for unskilled operators in
patients with uncomplicated / complicated airways
c. Visualization does not always lead to successful
intubation! ETT stylet is recommended when video
laryngoscopy is performed to facilitate intubation,
where bending the stylet and ETT in a manner
similar to the bend in the curve of the blade often
facilitates passage of ETT into the trachea
2. Flexible fiberoptic bronchoscopes:
a. Allows indirect visualization of larynx in patients
with unstable cervical spine, poor range of motion
of TMJ, certain congenital anomalies, or acquired
airway anomalies.
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b. Constructed of coated glass fibers that transmit light
and images by internal reflection
G. Techniques of direct and indirect laryngoscopy and intubation
a. Indications of intubation:
i. This is not a risk free procedure, not all patients with GA requires
this
ii. Indicated in patients who are at risk of aspiration and those
undergoing surgical procedures involving body cavities, head and
neck.
iii. Mask ventilation or ventuilation with LMA usually suffice for:
1. Cytoscopy
2. Examination under anesthesia
3. Inguinal hernia repairs
4. Extremity surgery
b. Preparations for direct laryngoscopy:
i. Check equipment and positioning of the patient
ii. TT should be examined and testing cuff inflation using 10mL syringe
iii. Some anesthesiologist cut the TT to preset length because:
1. Minimize dead space
2. Risk of bronchial intubation
3. Risk of occlusion from tube kinking
iv. Connector pushed firmly into the
tube to minimize disconnection
v. If using a stylet, it should be
inserted into the TT which is then
bent to resemble a hockey stick > facilitates intubation of
anteriorly positioned larynx
vi. Desired blade is locked into the
handle and bulb function is tested
vii. Extra handle, blade, TT, and stylet, functioning suctioning unit
should immediately be available
viii. Patient’s head should be level with anesthesiologist’s waist or higher
to prevent back strain
ix. Moderate head elevation (5-10cm from surgical table) and
extension of atlantooccipital joint -> sniffing position. Lower portion
of cervical spine is flexed by resting head on pillow or other soft
support
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x. Preoxygenation -> administration of 100% O2 -> margin of safety in
case patient is not easily ventilated after induction
xi. Failing to preoxygenate -> increases risk of rapid desat after apnea
xii. GA abolishes patients’ protective corneal reflex! Therefore care
must be taken to prevent injury to patient’s eyes by abrading the
cornea!
c. Orotracheal intubation:
i. Laryngoscope is held with left hand, and blade is introduced to right
side of oropharynx (avoid the teeth!) with the tongue swept to the
left and up into the floor of pharynx
ii. Tip of curved blade is inserted into vallecula, and straight blade tip
covers the epiglottis
iii. Handle is raised up and away from patient perpendicular to
patient’s mandible to expose vocal cords
iv. Avoid -> trapping lip between teeth and blade or leverage on the
teeth
v. TT is taken with right hand and its tip is passed through the vocal
cords. Backward-upward-rightward-pressure (BURP) procedure can
be done to monve an anteriorly positioned glottis posterior to
facilitate visualization of glottis.
vi. TT cuff should lie in the upper trachea, beyond the larynx
vii. While withdrawing laryngoscope, avoid tooth damage!
viii. Cuff is inflated with least amount of air to create seal during positive
pressure ventilation to minimize pressure damage to trachea
(Overinflation >30mmHg may inhibit capilary blood flow of trachea)
ix. Immediately ausculate the chest and epigastrium, and put on
capnographic tracking (definitive test) to ensure intratracheal
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xv.
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location. If doubt whether tube is in
esophagus or trachea, then repeat
laryngoscopy
Tube is then taped or tied to secure
position
Capnograph does not exclude
possibility of bronchial intubation ->
signs of which is often increase in
peak inspiratory pressure. Proper
tube location can be reconfirmed by
palpating the sternal notch while
compressing the pilot balloon.
Cuff shouldnt be left above the
cricoid cartilage for far too long
because it can cause post-operative
hoarseness and increases the risk
for accidental extubation
Oral intubation is poorly tolerated by awake and fit patient -> IV
sedation, local anesthetic spray in oropharynx, regional nerve block,
constant reassurance
Kalau gagal, do not try again the same way. Changes must be made
to increase likelihood of success -> repositioning of patient,
decrease tube size, adding a stylet, selecting different blade, using
indirect laryngoscope, attempting nasal rounte, or asistance of
another anesthesiologist is necessary
If patient is difficult to ventilate with mask, then alternative
management (LMA, combitube, cricothyrotomy, tracheostomy) can
be done.
Bougie can facilitate intubation when ETT cannot be directed into
glottis despite good visualization of laryngeal opening.
d. Nasotracheal intubation:
i. TT is advanced through nostril patient can breathe with–
nasopharynx – oropharynx before laryngoscopy
ii. Phenylephrine nose drop (0.5% or 0.25%) vasoconstrict vessels and
shirnk mucous membranes
iii. If patient is awake, then apply local anesthetic ointment (for nostril),
spray (for oropharynx), and nerve blocks
iv. TT lubricated with water-soluble jelly is introduced along the floor of
the nose below inferior turbinate at an angle perpendicular to the
face.
v. To ensure tube passes along the floor of nasal cavity, the proximal
end should be pulled cephalad
vi. Proceed until tip can be seen in oropharynx
vii. Laryngoscopy reveals the abducted vocal cords and TT is pushed
onwards. If there is difficulty, then tip of the tube may be directed
with Magill forceps but be careful not to damage the cuffs
viii. Great risk if patient has midfacial trauma -> intracranial placement
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e. Flexible fiberoptic intubation:
i. Routinely performed in awake or sedated patients with problematic
airways
ii. Ideal for:
1. Small mouth opening
2. Minimizing cervical movement in trauma or RA
3. Upper airway obstruction (angioedema, tumor)
4. Facial deformities, facial trauma
iii. Can be performed awake or asleep via oral or nasal routes
1. Awake: predicted inability to ventilate by mask, upper
airway obstruction
2. Asleep: failed intubation, minimal C spine movement in
patient who refuse awake intubation
3. Oral: facial, skull injuries
4. Nasal: poor mouth opening
iv. Likely add the anesthesia time prior to surgery
v. Airway is anesthesized with local anesthetic spray, patient sedation
is provided
vi. Dexmedetomidine -> advantage of preserving respiration while
providing sedation
vii. Both nostrils are prepared with vasoconstrictive drops, with
dominant nostril being identified.
viii. A large nasal airway can be inserted in contralateral nostril with
breathing circuit connected to administer 100% O2 during
laryngoscopy
ix. If patient unconscious and not breathing spontaneously, then
mouth can be closed and ventilation attempted through single nasal
airway -> MUST CONFIRM WITH CAPNOGRAPHY AND PULSE
O2METRY
x. The lubricated shaft of FOB is introduced to TT lumen, and make
sure that it is straight in alignment! At the distal end of the TT,
epiglottis or glottis should be visible.
xi. Advanced to within sight of carina (sign of proper positioning), and
TT pushed off the FOB
xii. Proper TT position is confirmed by viewing tip of the tube at
appropriate distance (3cm in adults) above the carina before FOB is
withdrawn.
f. Surgical airway techniques:
i. Required when “cant intubate, cant ventilate” scenario presents
ii. Options include:
1. Surgical cricothyrotomy-> incision of CTM to place breathing
tube. Seldinger catheter technique is utilized -> catheter
attached to a syringe (16 or 14 gauge) is inserted across
CTM. When air is aspirated, a guidewire is passed through
catheter into trachea. Dilator is passed over the guidewire
and breathing tube placed. THE CATHETER MUST BE
SECURED, with sufficient outflow of expired air must be
assured to avoid barotrauma. Short (1s) burst of O2 to
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ventilate the patient. Patients ventilated this way can
develop mediastinal emphysema or subcutaneous
emphysema.
2. Catheter or needle cricothyrotomy
3. Transtracheal catheter with jet ventilation
4. Retrograde intubation
H. Problems following intubation:
a. Detection of end-tidal CO2 remains gold standard to confirm placement of
ETT (harus ada cardiac output, ga bisa di pasien CABG or CP bypass)
b. Decreasing O2 sat can occur after tube placement,
i. often due to endobronchial intubation especially in small children
and babies
ii. Inadequate O2 delivery (O2 not turned on, patient not ventilated)
iii. VQ mismatch (almost any form of lung disease)
c. When sat declines, what to do?
i. Ausculate patient’s chest to listen for wheezes, rhonchi, rales
ii. Breathing circuit is checked
iii. Intraoperative chest radiograph needed to identify cause of desat
iv. Intraoperative fiberoptic bronchoscopy to confirm proper tube
placement and to clear mucous plugs
v. Bronchodilators and deeper planes of inhalation anesthetics -> to
treat bronchospasm
vi. Obese patients can desat due to reduced FRC and atelectasis
d. When end-tidal CO2 decline suddenly, what to do?
i. Consider pulmonary thrombus or venous air embolism
ii. Other causes of sudden decline in CO
iii. Leak in the circuit
e. Rising end-tidal CO2, what to do?
i. Hypoventilation
ii. Increased CO2 production -> malignant hyperthermia, sepsis
iii. Depleted CO2 absorber
iv. Breathing circuit malfunction
f. Increase in airway pressure may indicate obstructed or kinked ETT or
reduced pulmonary compliance -> suction the ETT to confirm patency and
lungs auscultated to detect bronchospasm, pulmonary edema,
endobronchial intubation, pneumothorax.
g. Decreases in airway pressure: can occur secondary to leaks in breathing
circuit or inadvertent extubation
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I.
J.
Techniques of extubation:
a. Most often, should be performed when patient is either deeply anesthetized
or awake -> adequate recovery from neuromuscular blocking agents should
be established
b. Extubation during light plane of anesthesia (antara deep and awake) is
avoided because increased risk of laryngospasm
c. To differentiate, suction the pharyngeal cavity. If there is reaction (cough,
holding breath) means the patient is in a state of light plane. If no reaction,
the patient is in a deep state
d. Eye opening or purposeful movements imply that the patient is sufficiently
awake for extubation -> associated with coughing on the TT
i. Increases heart rate
ii. Increases central venous pressure
iii. Increases arterial blood pressure
iv. Increases intracranial pressure
v. Increases intraabdominal pressure
vi. Increases intraocular pressure
vii. Can cause wound dehiscence and increased bleeding
viii. Presence of TT in asthmatic patient -> bronchospasm
ix. Decrease these effects by administering 1.5mg/kg IV lidocaine 1-2
minutes before suctioning and extubation
e. Patient’s pharynx should be suctioned prior to extubation to prevent
aspiration of mucous or blood into the lungs
f. Ventilate with 100% O2 in case it will be difficult to establish airway after TT
removal
g. Remember to remove the tape and uncuff the TT prior to extubation, and
remove the TT in a single smooth motion
Complication of laryngoscopy and intubation:
a. Airway trauma
i. Tooth damage is common
cause of malpractice claims
ii. Laryngoscopy and intubation
-> sore throat to tracheal
stenosis due to prolonged
external pressure -> tissue
ischemia, inflammation,
ulceration, granulation, and
hence stenosis.
iii. Cuff pressure of 20mmHg is
adequte to reduce
bloodflow to site by 75%. It
can be diminished by
hypotension
iv. Postintubation croup caused
by glottic, laryngeal, or
tracheal edema -> serious in
children. Efficacy of
corticosteroid
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(dexamethasone 0.2mg/kg up to maximum of 12mg) in preventing
this is controversial
v. Vocal cord paralysis from cuff compression or other trauma to the
recurrent laryngeal nerve -> hoarseness and increased risk of
aspiration
vi. Post-op hoarseness is seen more in obese, difficult intubations, and
anesthetic of long duration.
vii. Applying water-soluble lubricant or local anesthetic-containing gel
at tip or cuff of TT does not decrease incidence! Some research even
says otherwise!
viii. Smaller tubes (6.5 in women, 7.0 in men) -> fewer complaints of
postoperative sore throat
ix. Repeated attempts at laryngoscopy can lead to periglottic edema
and inability to ventilate with face mask -> deadly!!
b. Hypoxia
c. Hypercarbia
d. Dental and airway trauma
e. Tube malpositioning
f. Physiological response to airway instrumentation
g. Malfunction
K. Errors of TT Positioning:
a. Unrecognized esophageal intubation -> catastrophic (can cause esophageal
rupture, mediastinitis which presents as severe sore throat, fever, sepsis,
subcutaneous emphysema)
i. Prevented with direct visualization of tip of TT passing through vocal
cords
ii. Auscultation for presence of bilateral breath sounds and gastric
gurgling while ventilating through TT
iii. Analysis of exhaled gas for CO2
iv. Chest radiography
v. Use an FOB
b. Bronchial intubation (right more often than left)
i. Unilateral breath sounds
ii. Unexpected hypoxia with pulse oxymetry
iii. Inability to palpate TT cuff in sternal notch during cuff inflation
iv. Decreased breathing-bag-compliance (high peak inspiratory
pressure)
c. Cuff placement in larynx: laryngeal trauma. Can be identified by palpating
the cuff in the thyroid cartilage
d. Routine minimal testing includes: auscultation of the chest, routine
capnography, and cuff palpation
e. If patient is repositioned, then tube placement should be reconfirmed:
i. neck extension or lateral rotation -> TT away from carina
ii. Neck flexion -> moves tube toward the carina
L. Physiological response to airway instrumentation:
a. Laryngoscopy and tracheal intubation in light plane -> hypertension and
tachycardia
b. LMA is associated with less hemodynamic change
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c. Attenuation of hemodynamic changes can be accomplished by:
i. IV lidocaine, opioids, B-blockers, or deeper plane of inhalation
anesthesia minutes before laryngoscopy
ii. Hypotensive agents: sodium nitroprusside, nitroglycerin, esmolol,
nicardipine -> effective
iii. Cardiac arrhythmias particularly ventricular bigeminy can occur in
light plane anesthesia
d. Laryngospasm: forceful
involuntary spasm of laryngeal
musculature caused by sensory
stimulation of superior laryngeal
nerve
i. Triggering stimuli:
pharyngeal secretion,
passing TT through larynx
during extubation
ii. Prevented by extubating
patient while awake or
deeply asleep
iii. Treatment: positive
pressure ventilation with
anesthesia bag and mask
100% O2, or lidocaine IV
1-1.5mg/kg.
iv. If laryngospasm persist
and hypoxia develops,
succinylcholine 0.250.5mg/kg may be
required, or perhaps with small doses of propofol
v. Can result in negative-pressure pulmonary edema due to large
negative intrathoracic pressure
e. Aspiration can result from depression of laryngeal reflex due to prolonged
intubation and GA
f. Bronchospasm -> most common in asthmatic patient and is a clue to
bronchial intubation
g. Increased intracranial and intraocular pressure.
M. Tracheal tube malfunction:
a. Polyvinyl chloride may ignite by cautery or laser
b. Valve or cuff damage should be excluded prior to insertion
c. Obstruction can be caused by kinking, foreign body aspiration, thick
secretions in lumen
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