Transcript Compromised (difficult) airway

Adel Mikhail Fahmy, MD
Assistant professor of Anesthesia
Ain Shams University
Goals of airway management
1
2
3
Some factors in airway evaluation
History
• Previous
difficulty during
intubation
• Dental trauma
• Tracheostomy
scar
Mouth
opening (3
cm or more)
• TMJ diseases
• Trismus
Mallampati
class
•
•
•
•
I
II
III
IV
Two Important Airway Classifications:
A Cormack and Lehane classification of the view at laryngoscopy.
Grade I: most of the glottis is seen
Grade II: only posterior portion of glottis can be seen
Grade III: only epiglottis seen (none of glottis seen)
Grade IV: neither epiglottis nor glottis can be seen
B Mallampati classification of the oropharyngeal view; done with patient sitting, the head in the
neutral position, the mouth wide open, and the tongue protruding to the maximum.
Class I: visualization of the soft palate, fauces, uvula, anterior and posterior pillars.
Class II: visualization of the soft palate, fauces and uvula.
Class III: visualization of the soft palate and base of uvula.
Class IV: soft palate is not visible.
Some factors in airway evaluation
Thyro-mental
distance
• (6 cm or more)
Teeth
Tongue
• Edentulous
patients
• Prominent teeth
• Large
• Immobile
• edematous
Some factors in airway evaluation
Neck
thickness
Head
mobility
• Thick neck can
cause difficult
airway
• Limited neck
extension can
lead to poor
laryngeal view
Mandibular
protrusion &
submandibular
tissue compliance
What is the difficult airway?
Difficult intubation:
 Inability to intubate within a certain time (10 min).
 Inability to intubate within a number of attempts at
direct laryngoscopy (3).
 Cormack and Lehane Grade 3 or 4 view of larynx
(epiglottis only or no laryngeal structures).
 Requirement for additional equipment other than
traditional laryngoscope.
Difficult ventilation:
 Inability to keep oxygen saturation > 90% with 100%
oxygen by facemask.
 Catastrophic failure of mask ventilation leads to
morbidity or mortality.
Causes of Difficult Airway:
I. Non-patient factors:
1. Who is intubating and who helps him.
2. Where is the intubation technique
performed.
3. What are the equipment and drugs
used.
4. What is the position of the patient
during intubation.
Causes of Difficult Airway:
II. Patient factors:
1. Stiffness/deformities: (Immobility of the neck
or inability to open the mouth) Arthritis,
ankylosing spondylitis, scleroderma, burn or
radiotherapy contractures and cranio-cervical
fixation devices. Also, oral submucous fibrosis
and joint stiffness in DM.
2. Swelling: morbid obesity, infections e.g.
epiglottitis or Ludwig’s angina, tumors, trauma
e.g. post-surgical oedema or hematoma, neck
swellings e.g. thyroid & mediastinal tumors,
lingual tonsils.
Limited mouth opening as a result of TMJ disease
Stiffness. Rheumatoid arthritis affecting cervical spine and
temporomandibular joint
Obese individuals may be both difficult to ventilate and also
difficult to intubate as a result of redundant folds of
oropharyngeal tissue and decreased chest wall compliance
Glottic rheumatoid arthritis. The arytenoids and
ary-epiglottic folds are swollen and the airway is
narrow
Epiglottitis in a child
Laryngo-tracheo-bronchitis
Cavernoma causing airway obstruction
Causes of Difficult Airway:
II. Patient factors:
3. Foreign bodies: Accidental inhalation in
children or alcoholic adults, dentures, vomiting
& aspiration of solids and liquids during
induction of anesthesia.
4. High tariff: uncooperative patients, full
stomach, difficult venous access, and VIPs.
These
stressful
factors
can
degrade
performance.
Two classic difficult airways:
I.
Rheumatoid arthritis:





Cranio-cervical junction involved.
Temporo-mandibular joint involved.
Glottic stenosis.
Direct laryngoscopy often difficult.
Stridor common on extubation.
II. Acromegally:





Tissue hypertrophy.
Glottic stenosis.
Mask ventilation can be difficult.
Direct laryngoscopy can be difficult.
Complete obstruction on extubation.
Procedural classification:
I. Mask anesthesia: Having to use 2 hands to
control the airway, with an assistant
squeezing the bag, and oral and nasal
airways in situ is defined as difficult airway.
 Predictors of Difficult Mask Ventilation
• Age over 55 years
• Body mass index exceeding 26 kg/m2
• Presence of a beard
• Lack of teeth (edentulous)
• History of snoring
Procedural classification:
II. Difficult LMA insertion: Insertion of
LMA becomes more difficult when
mouth opening is restricted. The
lower limit of normal mouth
opening in young adults is 3.7 cm,
but LMA can be inserted with about
2.5 cm of inter-incisor distance.
Procedural classification:
III. Difficult direct laryngoscopy: This is used to be
referred to as the difficult airway. A difficult direct
laryngoscopy patient may be easily intubated with a
fiberoptic endoscope.
The Cormack and Lehan system:
Grade 1: the whole glottis is seen till the anterior
commissure.
Grade 2a: part of the vocal cords is visible.
Grade 2b: only the arytenoids are visible.
Grade 3: only the epiglottis is visible.
Grade 4: No glottic structure is visible.
N.B: Grade 2b and many of grade 3 patients can be intubated with the aid of a gumelastic bougie.
Two Important Airway Classifications:
A Cormack and Lehane classification of the view at laryngoscopy.
Grade I: most of the glottis is seen
Grade II: only posterior portion of glottis can be seen
Grade III: only epiglottis seen (none of glottis seen)
Grade IV: neither epiglottis nor glottis can be seen
B Mallampati classification of the oropharyngeal view; done with patient sitting, the head in the
neutral position, the mouth wide open, and the tongue protruding to the maximum.
Class I: visualization of the soft palate, fauces, uvula, anterior and posterior pillars.
Class II: visualization of the soft palate, fauces and uvula.
Class III: visualization of the soft palate and base of uvula.
Class IV: soft palate is not visible.
DIFFICULT AIRWAY EMERGENCY KIT
1. Rigid laryngoscope blades of alternate design and
size from those routinely used; this may include a
rigid fiberoptic laryngoscope (e.g., Bullard
laryngoscope).
2. Tracheal tubes of assorted sizes.
3. Tracheal tube guides. Examples include (but are
not limited to) semirigid stylets, ventilating tube
changer, and forceps (e.g., McGill forceps)
designed to manipulate the distal portion of the
tracheal tube.
4. Laryngeal mask airways of assorted sizes; this
may include the intubating laryngeal mask airway.
DIFFICULT AIRWAY EMERGENCY KIT
5. Flexible fiberoptic intubation equipment.
6. Retrograde intubation equipment. (e.g., kit from
Cook)
7. At least one device suitable for emergency
noninvasive airway ventilation. Examples include (but
are not limited to) an esophageal tracheal combitube
(Tyco Healthcare Nellcor Mallinckrodt, Pleasanton,
CA, www.combitube.org), a hollow jet ventilation
stylet and a transtracheal jet ventilator.
8. Equipment suitable for emergency invasive airway
access (e.g., Melker cricothyrotomy kit from Cook).
9. An exhaled CO2 detector.
Bullard Laryngoscope (rigid fiberoptic laryngoscope)
McCoy Laryngoscope with an articulating tip that can be
used to lift a big epiglottis out of the way.
CAN VENTILATE, CAN’T INTUBATE
• Ensure help is available and pulse oximeter and
capnography are in place before starting.
• Preoxygenate generously.
• Make sure head position is optimized (“sniffing
position”).
• Note the “grade” of view at laryngoscopy. (This will
be needed when you write a note in the patient’s
chart about why the patient was difficult to
intubate.)
• Ensure normocapnia and adequate depth of
anesthesia between intubating attempts.
CAN VENTILATE, CAN’T INTUBATE
• Decide how to approach your second attempt.
Would a larger blade (e.g., MAC 4) help? Would a
straight blade (e.g., Miller) help? Would a McCoy
blade help lift the epiglottis out of the way?
Would a Gum Elastic Bougie help? Would
external laryngeal manipulation help to move the
larynx into a less anterior position?
• You are allowed one final third attempt. Wisdom
may dictate that you give this chance to an
experienced anesthesiologist.
CAN VENTILATE, CAN’T INTUBATE
• If the patient can’t be intubated after three tries,
allow the patient to awaken and proceed with
awake intubation using a FOB technique.
• Alternatives to consider: Trachlight; Gum Elastic
Bougie (Echman stylet); Insert intubating LMA
(Fastrach); Insert an LMA ProSeal or a Combitube
to allow application of high ventilatory pressures
and to help prevent aspiration; Use a SyracusePatil face mask to facilitate fiberoptic intubation
(keeping patient asleep); Retrograde intubation
technique
Trachlight Intubation System
Retrograde intubation technique
Bail-Out" Algorithm CAN’T
VENTILATE WELL CAN’T INTUBATE
To awaken patient after failed intubation, where ventilation is difficult. This is a
setting where you simply want the patient to wake up and breathe
spontaneously.
1. Ensure that the patient is not in laryngospasm and that the patient’s head and
jaw are positioned properly. Call for help. Insert an airway of some kind
• oral airway
• nasopharyngeal airway
• LMA (Laryngeal Mask Airway)
• ILMA (Intubating LMA)
• Combitube (especially with LMA placement failures)
• Laryngeal tube
2. In some cases it will be helpful to utilize a two-person technique whereby one
person manages the mask and holds the jaw in position using both hands
(“jaw thrust maneuver”), while the other ventilates the patient by hand using
the rebreathing bag and the emergency oxygen flush as needed.
3. As a last resort, a surgical airway (e.g., cricothyrotomy) or TTJV is sometimes
needed.
Inhalational induction:
- Obstruction of the airway and loss of pulmonary
ventilation causes cessation of administration of
anesthetic agent and gradual re-awakening
(automatic feedback).
- Sevoflurane has almost universally replaced
halothane.
Awake fiberoptic intubation:
- In elective surgeries of patients with known
difficult airway.
- The awake patient maintains his or her own
airway until it is secured.
Awake tracheostomy:
- Very safe for patients with perilaryngeal tumors
and stridor.
Propofol with or without remifentanil in controlled
infusion induction:
- Can be used for patients with difficult airways, by
gradually increasing the rate of infusion to allow
deepening of anesthesia, whilst maintaining
spontaneous ventilation.
- If patient suffers central or obstructive apnea, the
infusion can be stopped and rapid redistribution
will allow lightening of anesthesia or full
awakening.
- These properties – maintenance of spontaneous
ventilation and redistribution during apnea –
have previously been the reasons for employing
inhalational induction in difficult airways.
- The advantage of inhaled agents over propofol is
that, on apnea, delivery ceases immediately and
automatically. Balanced against this are the
advantages of propofol:
1. suppression of airway reflexes.
2. achievement of adequate anesthesia not
affected by poor ventilation.
3. lack of lightening of anesthesia during airway
intervention.
- For awake fiberoptic intubation, the patient
experience and ease of the technique can be
improved by careful sedation with propofol or
remifentanil; these may be used singly or in
combination. The ultra-short acting opioid
remifentanil allows easy titration and rapid
reversibility of deep levels of analgesia sedation.
Thank You