Difficult airway management in ICU

DIFFICULT AIRWAY
MANAGEMENT IN ICU
DR SANJAY CHUGH (Associate Consultant)
DR VISHAL KR KANDHWAY(Senior resident)

INTRODUCTION
 The difficult airway is a common problem in adult critical care
patients. However, the challenge is not just the establishment of a
safe airway, but also maintaining that safety over days, weeks, or
longer.
 Definition: Aiway difficulty can be considered under 2 headings-
a) Difficult mask ventilation
b) Difficult tracheal intubation

 These may be encountered together or in isolation.
 DMV can be defined as the inability of an unassisted anesthesiologist
a) to maintain oxygen saturation, measured by pulse oximetry, >92%; or
b) to prevent or reverse signs of inadequate ventilation during positive-pressure mask
ventilation under general anesthesia.
 Difficult tracheal intubation (DTI) is tracheal intubation requiring “multiple intubation
attempts in the presence or absence of tracheal pathology“. However, there is no
universal definition and because the expertise of the intubator, the equipment used, and
the number of attempts made may vary.
 DTI may be the result of difficulty in visualization of the larynx—termed difficult direct
laryngoscopy or anatomic abnormality (distortion or arrowing of the larynx or trachea)
 Visualization of the larynx is usually described using the Cormack and Lehane grades
with grades 3 and 4 indicating DDL.

 Managing the Difficult Airway
This has been considered under three headings:
a) the anticipated difficult airway;
b) the unanticipated difficult airway;
c) the difficult airway resulting in a “cannot
intubate and cannot ventilate”

 Awake Intubation
Awake intubation is more time-consuming,
needsexperienced personnel, is less pleasant (thanintubation
under anesthesia), and may have to be abandoned as a
result of the patient's inability or unwillingness to cooperate.
However, because spontaneous breathing and
pharyngeal/laryngeal muscle tone is maintained, it is
significantly safer.

Intubation Under Anesthesia
 Despite the safety advantage of awake intubation in these patients
, anesthesia before attempted orotracheal intubation may be viewed as more
appropriate. This strategy should only be used by those skilled and
experienced in airway management. Preparation of the patient, equipment,
and staff is paramount. Adjuncts (see subsequently) should be available, either
to improve the chances of intubation or to provide a safe alterna-tive airway if
intubation cannot be achieved. The central principle is the in-duction of deep
anesthesia, sufficient to allow direct laryngoscopy and tracheal in-tubation
without the use of a muscle re-laxant, with maintenance of spontaneous
respiration. This involves an inhalational induction using a volatile agent (for
example, sevoflurane) or the slow administration of the iv agents like propofol
followed by inhalation technique.

Fiberoptic intubation
 Awake fiberoptic intubation is the technique of choice with an informed,
prepared patient and a trained operator with appropriate equipment. The
technique ensures that spontaneous respiration and upper airway tone can
be maintained.
 Adequate psychological preparation is essential. Numerous sedation agents
including benzodiazepines, opioids such as remifentanil, and intravenous
anesthetic agents such as (low-dose) propofol infusion. Supplemental
oxygen should be provided, usually through the contralateral nostril. Care
must be taken not to overdose the patient and to maintain spontaneous
respiration throughout.
 Topical anesthetic agents include lignocaine . Nebulized lignocaine can be
used but may result in high blood lignocaine levels, coughing, and
bronchospasm. Anesthesia of the vocal cords and upper trachea is usually
provided by a “spray as you go” technique using 2% lignocaine. Another
potential technique is superior laryngeal and recurrent laryngeal nerve
block.

 Fiberoptic intubation is more straightforward & frequently done through
nasal route then oral route.
 The operator stand behind the patient’s head. Vocal cords are visualized
and then lignocaine is sprayed through the cords.
 Scope is then advanced to the mid-tracheal level and carina is visualized
.
 The ETT may then be placed carefully & confirmation is made by EtCO2.

Fiberoptic Intubation (FBI)
 The use of a flexible bronchoscope to intubate
 The endotracheal tube is passed directly over the bronchoscope into the
trachea
 Uses: - Patients with difficult airways
- Pre-operative assessment
- Extubation assessment

 Advantages:
– This technique allows direct visualization of the airway
– Direct confirmation of ETT placement
– Can be done awake
 Disadvantages:
– Expensive,, requires care and skill
– View may be hampered by blood or secretions

Bimanual laryngoscopy
 Backward pressure on the cricoid cartilage,
 or the BURP maneuver (backward, upward, and rightward pressure),
 applied by an assistant may improve the view of the larynx at direct laryngoscopy.
 However, cricoid pressure and BURP, when performed by a “blinded” assistant, has
also been shown to impair laryngeal visualization on some occasions.
 External laryngeal manipulation (also termed bimanual laryngoscopy) involves a
cricoid pressure- or BURP-type maneuver performed initially by the laryngoscopist
and then maintained by an assistant.
 It has been shown to improve the view at direct laryngoscopy. Direct comparison has
shown that external laryngeal manipulation (bimanual laryngoscopy) is superior to
BURP in improving laryngeal visualization, whereas cricoid pressure is the least
effective technique.

Stylet
 The stylet is a smooth, malleable metal or plastic rod
 that is placed inside an ETT to adjust the curvature, typically into a J or
“hockey stick” shape to allow the tip of the ETT to be directed through a
poorly visualized or unseen glottis.
 The stylet must not project beyond the end of the ETT to avoid potential
airway injury.

Bougie
the gum elastic bougie is a blunt-ended,
malleable rod that may be passed through the poorly or non-visualized
larynx by putting a J-shaped bend at the tip and passing it “blindly” in the
midline upward beyond the base of the epiglottis.
The ETT can then be “rail-roaded” over the bougie, which is then
withdrawn. For many, it is the first choice adjunct in the difficult intubation
situation

Difficult airway management in ICU

Light wand
 The light wand is a malleable fiberoptic light source on which an ETT can be
mounted and subsequently railroaded into the trachea when the light source
has passed beyond the glottis. It facilitates blind tracheal intubation by
distinguishing the tracheal lumen from the (more posterior) esophagus as a
result of the greater intensity of light visible through anterior soft tissues of
the neck as the light source passes beyond the vocal cords. It may be used
in conjunction with the laryngeal mask airway or as part of a combined
technique with a fiberoptic scope. A potential disadvantage is the need for
low ambient light, which may not be desirable (or easily achieved) in a
critical care setting. Light wand devices may be contraindicated in patients
with known abnormal upper airway anatomy and those in whom detectable
transillumination is unlikely to be adequately achieved.

Supraglottic Devices
 Supraglottic devices are the suitable alternative to
endotracheal intubation, Useful when endotracheal
intubation has failed
 Suitable for use by those with limited experience with
endotracheal intubation
 Should be immediately available for every difficult
airway situation
 Various types available

I GEL
 2nd generation Supraglottic airway device
 Single use SAD
 Made of Medical grade thermoplastic elastomer
SEBS (Styrlene ethylene Butadiene styrene)
ADVANTAGES
 Allows ease of insertion and reduced trauma
 Gastric channel to prevent aspiration
 Integral bite block
 Eliminates rotation
 Reduces possibility of epiglottis downfolding and
obstructing airway

INTUBATING LMA
Rigid, anatomically curved, airway tube that
is wide enough to accept an 8.0 mm cuffed
ETT and is short enough to ensure passage
of the ETT cuff beyond the vocal cords.
Epiglottic elevating bar in the mask aperture
which elevates the epiglottis as the ETT is
passed through.
Available in three sizes, one size for children,
two sizes for adults

LMA Pro-Seal
 Not necessarily a Difficult Airway Device,
but is useful in situation where patient
has not been fasting
 May be useful in failed obstetric
intubation
 This has an extra tube which provides
excess access to stomach contents
 Protects against aspiration by providing
an escape for unexpected regurgitation
 Drain tube prevents against gastric
insufflation

LMA Supreme™
 Quite new to the market, combines all the
best features of all previous LMA except
you can’t intubate through it
 The SLMA is easily and rapidly inserted,
providing a reliable airway and a good
airway seal
 Rates of failure, manipulations required
and complications are very low.
 Can be used when tracheal intubation fails
in non-fasted patients
 Useful in “failed intubation” and the “can’t
intubate-can’t ventilate” situation

COMBITUBE
 The Combitube is a combined esophageal obturator and tracheal tube and is usually
inserted blindly.
 Whether the “tracheal” lumen is placed in the trachea or esophagus,
 the Combitube will allow ventilation of the lungs and give partial protection against
aspiration.
 In many situations, the Combitube is a (less widely used) alternative to the LMA,
including the “cannot intubate- cannot ventilate” situation.
 Disadvantages include the inability to suction the trachea when placed in the
esophagus (the most common position). Insertion may also cause trauma and is
contraindicated in patients with known esophageal pathology, intact laryngeal
reflexes, or in those who have ingested caustic substances

ESOPHAGEAL- TRACHEAL COMBITUBE
Useful as emergency airway
Two lumens allow function whether place
in esophagus or trachea
Esophageal balloon minimizes aspiration

FAILURE TO INTUBATE & FAILURE TO VENTILATE
 This is an absolute emergency and a grave threat to life. To ensure all involved
perform at their best, it is important to remain calm and follow an appropriate
algorithm. The options are to find a satisfactory method of ventilation without
intubation (“noninvasive”) or to perform a cricothyroidotomy or (potentially)
tracheostomy. Reduced to its simplest, the options are
a) check the basics to see if intubating conditions can be improved
b) use of a supraglottic airway
c) perform a cricothyroidotomy , which may be more easily remembered using the
phrase “Fiddle, Larry, Stick”.

SURGICAL AIRWAY
 The indication for a surgical airway is inability to intubate the trachea in a patient who
requires it and the techniques available are cricothyroidotomy or tracheostomy.

 Cricothyroidotomy may be performed using three techniques: needle, wire-guided
percutaneous, or surgical.

SURGICAL TECHNIQUES
 A cricothyrotomy is only indicated when all other devices and
techniques have failed or are not available
 Final step for CICV in all airway algorithms
 Quicker than a tracheotomy
 Life saving
 Convert to definitive airway asap
 Must be provided on all carts

SURGICAL AIRWAY TECHNIQUE
3 different techniques
 Needle Cricothyrotomy +TTJV
(Manujet)
 Large Cannulae Cricothyrotomy (Melker / Quicktrach)
 Surgical Cricothyrotomy

Pre-oxygenation and apnoeic techniques to
maintain oxygenation
 Preoxygenation with 20-25 degree head up position and continuous
positive airway pressure – delays onset of hypoxia
 Nasal oxygenation during efforts of securing endotracheal tube –
increases the apnoeic time

Choice of laryngoscope blades
 There are over 50 types of curved and straight laryngoscope blades of
varying sizes. Using specific blades in certain circumstances is felt to be very
advantageous by some but not all. In patients with a large lower jaw or “deep
pharynx,” the view at laryngoscopy may be improved significantly by using a
size 4 Mackintosh blade (rather than the more common size 3) to ensure the
tip of the blade reaches the base of the vallecula to facilitate optimal elevation
of the epiglottis. Other blades, for example, McCoy (a curved Mackin-tosh-type
blade with a laryngoscopist controlled hinged portion just proximal to the tip),
may be advantageous in specific situations.

 SNIFFING POSITION:
CONVENTIONAL LARYNGOSCOPY

 A difficult laryngoscopic view is found (i.e. Cormack and Lehane Grade III or IV),
then it is reasonable to have one further “best” attempt at Laryngoscopy which
should consist of the following components:
• an attempt by an experienced laryngoscopist,
• an optimal patient head and neck position
• external laryngeal manipulation,
• consider adjuncts to Laryngoscopy,
• consider a single change of laryngoscope blade size and type,
• consider using a smaller sized endotracheal tube.
Difficult direct laryngoscopy

EXTERNAL LARYNGEAL MANIPULATION (BURP MANEUVER):
--
-Backward
-upward
-rightward pressure
Helps to increase laryngoscopic view.
Different from Sellick’s manuever

MILLER BLADES (STRAIGHT)
The Miller blades are
commonly used for infants.
It is easier to visualize the
glottis using these blades
than the Macintosh blade in
infants, due to the larger
size of the epiglottis relative
to that of the glottis.

LEVERING LARYNGOSCOPE (MCCOY)
 Hinged tip which facilitates
elevation of the epiglottis
 Less force required to intubate
 Improves view at laryngoscopy
 Useful in patients wearing cervical
hard collars
 Inexpensive
 Steep learning curve

VIDEOLARYNGOSCOPES
Un-channelled videolaryngoscopes
 These devices can facilitate
visualization of the larynx when it
is not possible to do so with a
conventional blade.
 To achieve actual intubation the
ET tube has to be loaded onto a
stylet, then navigated into the field
of view of the videolaryngoscope,
and finally advanced into the
laryngeal inlet.
Eg: Glidescope and C-Mac®
Types of videolaryngoscopes
Videolaryngoscopes are either of the un-channelled or channelled type:

Channelled videolaryngoscopes
 These devices include a
channel for the ET tube which
is integrated into the blade of
the laryngoscope.
 The Airtraq® is an example of
a channelled videolaryngosco
 Air trach

ADVANTAGES
 Better laryngeal view
 Shorter duration of intubation time
 Reduced mucosal injury
 Reduced external manipulation
 Bigger screen

Bullard rigid fiberoptic
laryngoscope

NEEDLE CRICOTHYROTOMY
(MANUJET III WITH JET VENTILATION CATHETER)
 Useful for elective or emergency TTJV
 Perc puncture of cricothyroid ligament
 It consists of an injector with pressure gauge and adjustable driving pressure (0-4 BAR)
 Catheters available in 3 sizes Adult 13g, Child 14g and Baby 16g

TRANSTRACHEAL JET VENTILATION (TTJV)
 Jet ventilation using either specialized ventilator or high pressure driven valve
circuit via a catheter passed through the cricothyroid membrane
 Similar technique to previous
 Disadvantages
 Requires high pressure gas source
 May cause subcutaneous emphysema, pneumo-mediastinum, pneumothorax or
other types of barotrauma
 Uses:
 Emergency ventilation in the can’t intubate can’t ventilate scenario

CRICOTHYROTOMY CATHETER
(MELKER CUFFED/ QUICKTRACH)
 Syringe
 18g Introducer Needles
(5cm & 7cm)
 Guidewire
 Curved Dilator
 Airway Catheter

LARGE CANNULAE CRICOTHYROTOMY
 Used for emergency airway access when conventional ett intubation cannot be
performed
 Percutaneous entry ( seldinger ) technique via cricothyroid membrane
 Dilate the tract and tracheal entrance site to permit passage of the emergency
airway
 Cuffed catheter to protect and control airway

SURGICAL CRICOTHYROTOMY
Requirements:
 No 11 blade
 Size 6 Shiley tracheostomy
( OR small ETT size 5.0-6.0)
 Small artery forceps
Technique:
Head fully extended
longitudinal incision is made through the skin and subcutaneous fat over the thyroid
and cricoid cartilages
Tissue bluntly dissected
Cricothyroid ligament is transversely incised
Tracheal tube inserted

Retrograde Intubation
 Under local anesthesia, a cannula is inserted through the cricothyroid
membrane into the trachea and a guidewire is passed through the needle
upward through the vocal cords into the pharynx or mouth. If necessary,
forceps may be used to retrieve the guide-wire and bring it out through the
mouth. The wire is then used to guide an ETT (railroaded over an endotracheal
exchange catheter) through the vocal cords before the withdrawal of the wire
through the cannula and further advancement of the ETT into the trachea. A
common variation to this technique is to use the wire to guide a fiberoptic
scope through the vocal cords, thus facilitating a fiberoptically guided
intubation. With this technique, the wire must be longer than the fiber-optic
scope plus the airway down to the glottis. A long angiography guidewire is
appropriate, whereas a central venous catheter guidewire is not.

TFE catheter: prevent the ET tube form redundancy
over the guidewire  decrease trauma, increase
success rate

Difficult airway management in ICU

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