Introduction to Clinical Airway Management

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Introduction to Clinical Airway Management

• D. John Doyle MD PhD Professor of
  AnesthesiaCleveland Clinic

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Clinical Airway Management Series

• Part 1 Introduction to Clinical Airway Management
• Part 2 Airway Gadgets / Fiberoptic Intubation
• Part 3 Lessons from the School of Hard Knocks
• Part 4 Some Interesting Airway Cases

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Download this four-part talk series
athttp//doyleairwaytalks.homestead.com
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OUTLINE

• Goals of Clinical Airway Management
• The Past
• Preoperative Evaluation of the Airway
• Airway Management Options
• ETT Placement Confirmation
• Supraglottic Airway Devices
• Awake Intubation
• Transtracheal Jet Ventilation
• Video Laryngoscopy
• Airway Algorithms

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Objectives

• At the end of this presentation learners should
  be familiar with the following
• Key management decisions to make in difficult
  airway cases
• Three airway situations you must always have a
  plan for
• The notion of an airway management algorithm
• Recognizing situations where intubation will be
  very difficult
• The art and science of awake intubation
• Routine and specialized equipment for
  laryngoscopy / intubation

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Airway Facts

• 1.More than 85 of all respiratory-related
  malpractice claims in the US involve a
  brain-damaged or dead patient (Caplan et al
  1990).
• 2.Poor management of the difficult airway
  accounts for as many as 30 of deaths due to
  anesthesia (Benumof and Scheller 1989).
• References
• 1. Caplan RA, Posner KL, Ward RJ et al. Adverse
  respiratory events in anesthesia a closed claims
  analysis. Anesthesiology 72 828-833 (1990).
• 2. Benumof JL, Scheller MS. The importance of
  transtracheal jet ventilation in the management
  of the difficult airway. Anesthesiology 71
  769-778 (1989).

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Three Basic Management Choices...to be made for
each airway situation

• 1. Nonsurgical vs surgical airway for the initial
  approach to intubation
• 2. Maintenance of spontaneous breathing vs
  breathing for the patient
• 3. Awake intubation vs intubation after induction
  of general anesthesia

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Major Techniques of Airway Management

• Bag mask ventilation
• Endotracheal intubation
• Supraglottic airway devices
• Surgical airway management

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Goals of Clinical Airway Management
Choice of technique will depend on management
goals
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Clinical Airway Management Has Three Goals

• Maintenance of adequate oxygenation (as measured
  by PaO2 or SaO2)
• Maintenance of adequate ventilation (as measured
  by ETCO2 or PaCO2)
• Protection of the airway from injury (avoiding
  aspiration, barotrauma, infection etc.)

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Oxygenation

• Oxygenation is controlled principally by
  adjusting the fraction of inspired oxygen (FI02 )
  setting on the ventilator, although PEEP
  adjustment is equally important to improve
  oxygenation in patients with acute lung injury

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Oxygenation PEEP

• PEEP or positive end expiratory pressure, is the
  minimum lung distending pressure over expiration
  (see parameter 1 in figure)
• It is usually set between 2 and 5 cm H2O in
  patients with normal lungs

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Oxygenation PEEP
http//www.aic.cuhk.edu.hk/web8/Hi20res/Self20i
nflating20resuscitator20PEEP20valve.jpg
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Controlling Ventilation

• Ventilation is determined by adjusting two things
  on the ventilator
• tidal volume (TV)
• and
• respiratory rate (RR)
• TV typically 10 ml / kg (unless permissive
  hypercapnea desired)
• RR typically 10 / min

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Protection of the Airway From Soiling and Injury

• Protection of the airway from soiling due to
  aspiration of gastric contents is achieved in
  unconscious patients (due to general anaesthesia
  or head injury) by using a cuffed endotracheal
  tube.

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Aspiration Pneumonitis

• Unintubated patients may develop deadly
  aspiration pneumonitis if stomach contents spill
  into the lungs (especially if the pH is lt 2.5 or
  aspirated volume gt 25 ml).

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THE PAST
McCardie (1865 to 1939) mask for application of
open-drop inhalational anesthesia.
http//www.agai.at/eng/museum/default.htm
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Zang mouth gag with the end of the arms protected
by rubber from the Collection of Anesthesia and
Intensive Care Medicine at the Institute for the
History of Medicine in Vienna (Austria) catalog
number 3.47.
THE PAST
http//www.adair.at/eng/museum/equip/mouthgag/zang
1.htm
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Kuhn tracheal intubation set from the Collection
of the Instrument Maker Carl Reiner (Vienna,
Austria). The manufacturer is unknown.
THE PAST
About 1900, Franz Kuhn (1866 to 1929, German
surgeon) developed a tracheal intubation set.
Unfortunately, most of his surgical colleagues
did not recognize the importance of tracheal
intubation since they were influenced by the
surgeon Ferdinand Sauerbruch (1875 to 1951) who
refused to use this technique.
http//www.adair.at/eng/museum/equip/tracheal/kuhn
intubationsetobject01.htm
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THE PAST
http//www.adair.at/eng/museum/equip/tracheal/kuhn
intubationsetobject01.htm
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Major Techniques of Airway Management

• Bag mask ventilation
• Endotracheal intubation
• Supraglottic airway devices
• Surgical airway management

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Key Questions

• Is a supraglottic airway appropriate?
• Is there a significant aspiration risk?
• Will the patient tolerate an apneic period?

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Current Airway Management Options
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Option 1 Avoid GA

• Avoid general anaesthesia - do case under
  local or regional anesthesia with patient
  breathing spontaneously.

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Option 2 GA with SV

• General anesthesia (e.g. propofol infusion)
  with patient breathing spontaneously with an
  unprotected airway and only an oxygen mask.

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Option 3 GA with SV

• General anesthesia with patient breathing
  spontaneously with an unprotected airway using a
  nasopharyngeal airway.

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Option 4 SGA with SV

• Laryngeal mask airway or other SGA with
  patient breathing spontaneously (airway still
  unprotected against aspiration.)

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Option 5 SGA with PPV

• Positive pressure ventilation (PPV) using the
  laryngeal mask airway (LMA) or other SGA.

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Option 6 ETT with SV

• Spontaneous breathing with an airway protected
  using an endotracheal tube (ETT). An uncuffed
  ETT was once popular with children, but provides
  less complete protection against aspiration.

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Option 7 ETT with PPV

• Positive pressure ventilation (PPV) with an
  endotracheal tube (ETT). This is the most common
  option, at least for big cases

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Option 8 Surgical Airway

• A surgical airway (e.g. tracheostomy under
  local anesthesia, emergency cricothyroidotomy)
  may be required in exceptional circumstances.

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Transtracheal Jet Ventilation
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Preoperative Airway Evaluation
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• The Difficult Airway is something you anticipate,
• The Failed Airway is something you experience.
• (Walls, 2002)

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Airway Evaluation

• History interview / records
• Physical exam
• Imaging

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Some Clinical Tests

• Presence of facial dysmorphic features
• Atlanto-occipital mobility
• Mouth opening
• Visibility of oropharyngeal structures
• Thyromental distance
• Sternomental distance
• Dentition
• TMJ mobility

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Table 1. Components of the Preoperative Airway
Physical Examination. This table displays some
findings of the airway physical examination that
may suggest the presence of a difficult
intubation.
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Mallampati scoring system - 1983

• MP class I uvula, soft palate, faucial pillars
  are noted
• MP class II part of the uvula, soft palate,
  faucial pillars are noted
• MP class III only soft palate and the base of
  the uvula are visualized
• MP class IV soft palate is not visualized

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Mallampati / SamsoonYoung classification of the
oropharyngeal view. Class I uvula, faucial
pillars, soft palate visible Class II faucial
pillars, soft palate visible Class III soft
and hard palate visible Class IV hard palate
visible only (added by Samsoon and Young).
From Paul G. Barash, Bruce F. Cullen, Robert K.
StoeltingClinical Anesthesia 2001
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Mallampati Score Significance

• Poor sensitivity, specificity, PPV (positive
  predictive value)
• Interobserver variability
• Phonation improves specificity, but increases the
  false negative results
• Poor correlation with difficult bag mask
  ventilation
• Improved PPV when combined with other clinical
  tests

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Table 1. Components of the Preoperative Airway
Physical Examination. This table displays some
findings of the airway physical examination that
may suggest the presence of a difficult
intubation.
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Probability of experiencing a difficult
intubation for the combination of risk factors
Mallampati class I, II, III, or IV, short neck
(SN), protruding maxillary incisors (PI), or
receding mandible (RM). Data were obtained from
1500 patients undergoing cesarean delivery with
general anesthesia. Rocke et al.
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DL prediction is not VL prediction
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Tremblay et al. recorded demographic and
morphometric factors for 400 patients undergoing
tracheal intubation (TI). After induction, TI
using the GS was performed after the recording of
CL grade at DL. They found a high CL grades at
DL, a high upper lip bite test score, and a short
sterno-thyroid distance as predictors of
difficult GS TI. Obviously only the last two
factors can be assessed at the bedside.
VL DI prediction
Tremblay MH, Williams S, Robitaille A, Drolet P.
Poor visualization during direct laryngoscopy and
high upper lip bite test score are predictors of
difficult intubation with the GlideScope
videolaryngoscope. Anesth Analg. 2008
May106(5)1495-500
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Airway Management in the Field
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CPR Masks
Laerdal Pocket Mask
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Miniature CPR Barrier Masks
The MDI CPR Microkey
The Ambu Res-Cue Key is an inexpensive barrier
with a one-way valve that prevents direct
mouth-to-mouth contact
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OXYLATOR FR-300
The OXYLATOR FR-300 limits the maximum airway
pressure to 20 cm H2O and maintains a low
constant flow rate of 30 liters per minute.
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Emergency Suction
Laerdal V-Vac Suction Unit
replacement cartridge
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Airway Obstruction
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Complete Airway Obstruction

• Complete airway obstruction is usually managed
  by prompt intubation, but surgical airways are
  sometimes needed as a last resort when neither
  intubation nor ventilation is possible.

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http//images.webmd.com/static54/images/hwstd/medi
cal/pulmonol/n5551303.jpg
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Posterior Displacement of Tongue and Soft Palate

• Commonly, obstruction occurs, at least in
  part, when the tongue base falls back posteriorly
  to obstruct the oropharynx.
• Movement of the soft palate may also
  contribute to airway obstruction.

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http//images.webmd.com/static54/images/hwstd/medi
cal/pulmonol/n1573.jpg
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Head Tilt
http//www.brooksidepress.org/Products/Operational
Medicine/DATA/operationalmed/Manuals/HM32/Chapter
04/fig04-03.gif
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Jaw Thrust / Chin Lift
http//www.brooksidepress.org/Products/Operational
Medicine /DATA/operationalmed/Manuals/HM32/Chapter
04/fig04-04.gif
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Things that Make Mask Ventilation More Difficult

• facial obesity
• big, thick beard
• large jaw
• no teeth
• massive facial dressings
• recent nasal surgery
• delicate skin
• (burns, skin grafts, epidermolysis bullosa)

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Langeron O, Masso E, Huraux C, Guggiari M,
Bianchi A, Coriat P, Riou B Prediction of
difficult mask ventilation. Anesthesiology 2000
92122936
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Airway Adjuncts

• Airway adjuncts are often helpful in reducing
  airway obstruction in spontaneously breathing
  patients. These include oropharyngeal airways
  (usually adult sizes 8, 9, 10), nasopharyngeal
  airways (nasal trumpets inserted into one or
  both nostrils) or a supraglottic airway such as
  the laryngeal mask airway (LMA).

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Oropharyngeal Airway
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Nasopharyngeal Airway
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Supraglottic Airway Devices
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Laryngeal Mask Airway
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Laryngeal Mask Airway
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Flexible Laryngeal Mask
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Proseal Laryngeal Mask
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Intubating Laryngeal Mask
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http//spaceline.usuhs.mil/current2005/11-04/parab
olic_intubation.jpg
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Intubation
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Why Intubate?

• As part of general anesthesia
• Protect airway against aspiration
• Allow positive pressure ventilation (PPV)
• Allow airway suctioning (toilet)
• Allow drugs to be given in a code blue where IV
  access is not yet available
• epinephrine
• lidocaine
• atropine

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Methods of Tracheal Intubation

• Blind methods (including digital)
• Use of a laryngoscope
• Macintosh (curved blade)
• Miller (straight blade)
• Videolaryngoscopes
• Trachlight and similar methods
• Fiberoptic Intubation

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From Paul G. Barash, Bruce F. Cullen, Robert
K. StoeltingClinical Anesthesia 2001
(A) With the patient supine and no head support,
the oral, pharyngeal, and tracheal axes do not
overlap. (B) The sniff position maximally
overlaps the three axes.
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Intubation of obese patients can be greatly
facilitated by stacking blankets so as to achieve
the "head-elevated laryngoscopy position (HELP)
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An Aid To Airway Management For Obese Patients


Troop Elevation Pillow         Patent US
6,751,818 B1 (Mercury Medical)
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Normal Glottis
Photo Credit Dr John Sherry II
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Cherry Red Epiglottis (Epiglottitis)
Photo Credit Dr John Sherry II
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Cormack-Lehane Grading System Grade I most of
glottis is seen Grade II only posterior portion
of glottis can be seen (May not be ASA Task Force
"difficult" if some part of the vocal cords are
seen.) Grade III only epiglottis may be seen
(none of glottis seen)(ASA Task Force
"difficult.") Grade IV neither epiglottis nor
glottis can be seen (ASA Task Force "difficult.")
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Endotracheal tube placed fiberoptically through
the right orbit, which communicates with the
larynx. Sander M. Lehmann C. Djamchidi C. Haake
K. Spies CD. Kox M D WJ. Fiberoptic transorbital
intubation alternative for tracheotomy in
patients after exenteration of the orbit.
Anesthesiology. 971647, 2002
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http//www.nets.org.au/main/Intub1.jpg
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Laryngoscopes
http//www-personal.umich.edu/bwudcock/Guatemala/
Intubation.jpg
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Articulating Blade Laryngoscopes
Flexiblade by Arco Medic Ltd.
McCoy Laryngoscope
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Lighted Stylets
Macintosh Lighted Stylet In 1957, Sir Robert
Reynolds Macintosh and Harry Richards (Oxford,
England, UK) reported on a malleable introducer
for tracheal tubes which had an illuminated tip.
The proximal end was connected to a pocket
battery (Anaesthesia 12223-225, 1957). Berman
Lighted Stylet In 1959, Robert A Berman (Far
Rockaway, New York, USA) described a malleable
introducer for tracheal tubes with an illuminated
tip (Anesthesiology 20382-383, 1959).
http//www.adair.at/eng/museum/equip/stylets/defau
lt.htm
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Trachlight
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Special ETTs
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EMT (Emergency Medicine Tube) Endotracheal Tubes
The EMT tracheal tube allows one to administer
medications into the patient's lungs without
interrupting CPR or disconnecting the tube.
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Endotrol (Trigger Tube)The Endotrol tracheal
tube is designed to facilitate intubation of
patients where aid is needed in controlling the
direction of the tip of the tube. The operator
controls the direction of the tip via a ring loop
located near the external connector.
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Beck Airway-Airflow Monitor

• Magnifies airway-airflow sounds
• Activated by patient's respiration
• No moving parts
• Simple to use
• Disposable

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• The Parker Flex-TipTM tubes are available in
  sizes 6.5, 7.0, 7.5, and 8.0mm ID.
• The tapered, centered, flexible tip of the Parker
  Flex-TipTM Endotracheal Tube is designed for
• Better tip visibility
• Gentle sliding off of delicate anatomical
  structures in the airway
• Easier insertion through narrow glottic openings
• Snag-free "railroading" along fiberoptic scopes
• Gentle "skiing" down tracheal walls

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Intubation Bougies
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The Eschmann Bougie is a yellow colored, 60 cm,
15 French, stiff stylet marketed by Portex as
Catalog Number 103014 and manufactured in England
by Eschmann Health Care. It is fabricated from a
braided polyester base with a resin coating. It
costs around 75 each and can be reused.
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Eschmann Bougie I have found this stylet to be
invaluable when faced with a difficult
intubation. The technique is simple. If the tip
of the epiglottis is visible, slide the upward
angled end of the bougie along the bottom of the
epiglottis, feeling gently for the unseen glottic
opening. It is unlikely that the bougie will be
directed into the more posterior esophagus if
care is taken to maintain contact with the bottom
of the epiglottis. Once the tip is thought to be
through the cords, continue to push it into the
trachea. With experience, a positive confirmation
of tracheal placement can be made by feeling the
"clicks" as the angled tip of the bougie passes
over the tracheal rings. A 6 or 7 mm endotracheal
tube is then passed over the stylet (the modified
Seldinger technique for intubation). If the tube
hangs up at the cords, simple twisting of the
tube will usually allow it to pass.
http//www.calsocanes.com/Bulletins/vol2047-4/tip
s984.pdf
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If you cant ventilate or intubate, call for help
and open the neck!
Airway Wisdom
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Spontaneous breathing is generally safer than
paralysis with positive pressure ventilation by
mask, especially in cases of airway obstruction
Airway Wisdom
Airway Wisdom
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The awake airway is the safest airway to manage

Airway Wisdom
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Have a low threshold for waking up the elective
patient you are having trouble intubating
Airway Wisdom
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Fiberoptic intubation is usually ill-advised in
dire emergency cases, even with experience. This
is especially true with an edematous, bloody
airway.
Airway Wisdom
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Airway Wisdom
If your first intubation attempt fails ---think
about what to do differently for attempt number
two.
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If you cant intubate, ventilate! If you
cannot intubate in two or three tries, go back to
the bag-mask-valve system and contemplate your
backup plan
Airway Wisdom
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If you cant ventilate, intubate!
Airway Wisdom
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Patients die from failure to oxygenate not from
failure to intubate.
Airway Wisdom
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If you never use special airway devices in
elective cases, you'll definitely not be elegant
and slick when you try to use it in an emergency.
Airway Wisdom
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The End