Transcript Introduction to Clinical Airway Management - Doyle-Airway

Introduction to
Clinical Airway
Management
D. John Doyle MD PhD
Professor of Anesthesia
Cleveland Clinic
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
Download this four-part talk series at
http://doyleairwaytalks.homestead.com
OUTLINE
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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
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
Airway Facts
1.More than 85% of all respiratory-related
malpractice claims in the US involve a braindamaged 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).
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
Major Techniques of Airway
Management
• Bag mask ventilation
• Endotracheal intubation
• Supraglottic airway devices
• Surgical airway management
Choice of technique will depend on management goals …
Goals of Clinical
Airway Management
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.)
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
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
Oxygenation: PEEP
http://www.aic.cuhk.edu.hk/web8/Hi%20res
/Self%20inflating%20resuscitator%20PEEP%20valve.jpg
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
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.
Aspiration Pneumonitis
Unintubated patients may develop
deadly aspiration pneumonitis if
stomach contents spill into the lungs
(especially if the pH is < 2.5 or aspirated
volume > 25 ml).
THE PAST
McCardie (1865
to 1939) mask
for application of
open-drop
inhalational
anesthesia.
http://www.agai.at/eng/museum/default.htm
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/zang1.htm
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/kuhnintubationsetobject01.htm
THE PAST
http://www.adair.at/eng/museum/equip/tracheal/kuhnintubationsetobject01.htm
Major Techniques of Airway
Management
• Bag mask ventilation
• Endotracheal intubation
• Supraglottic airway devices
• Surgical airway management
Key Questions
 Is a supraglottic airway appropriate?
 Is there a significant aspiration risk?
 Will the patient tolerate an apneic period?
Current Airway
Management
Options
Option 1
Avoid GA
Avoid general anaesthesia - do
case under local or regional
anesthesia with patient breathing
spontaneously.
Option 2
GA with SV
General anesthesia (e.g. propofol
infusion) with patient breathing
spontaneously with an unprotected
airway and only an oxygen mask.
Option 3
GA with SV
General anesthesia with patient
breathing spontaneously with an
unprotected airway using a
nasopharyngeal airway.
Option 4
SGA with SV
Laryngeal mask airway or other SGA
with patient breathing spontaneously
(airway still unprotected against
aspiration.)
Option 5
SGA with PPV
Positive pressure ventilation
(PPV) using the laryngeal mask
airway (LMA) or other SGA.
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.
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
Option 8 Surgical Airway
A surgical airway (e.g. tracheostomy
under local anesthesia, emergency
cricothyroidotomy) may be required
in exceptional circumstances.
Transtracheal Jet Ventilation
Preoperative Airway
Evaluation
The Difficult Airway is something you anticipate,
The Failed Airway is something you experience.
(Walls, 2002)
Airway Evaluation
• History – interview / records
• Physical exam
• Imaging
Some Clinical Tests
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Presence of facial dysmorphic features
Atlanto-occipital mobility
Mouth opening
Visibility of oropharyngeal structures
Thyromental distance
Sternomental distance
Dentition
TMJ mobility
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.
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
Mallampati /
Samsoon–Young
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;
From
Paul G. Barash,
Bruce F. Cullen,
Robert K. Stoelting
Clinical Anesthesia 2001
Class IV: hard palate
visible only (added by
Samsoon and Young).
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
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.
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.
DL prediction is
not VL prediction
Tremblay et al. recorded
demographic and
morphometric factors for
400 patients undergoing
tracheal intubation (TI).
VL DI prediction
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.
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
May;106(5):1495-500
Airway Management
in the Field
CPR Masks
Laerdal Pocket Mask
Miniature CPR Barrier Masks
The MDI CPR Microkey
The Ambu Res-Cue Key is an
inexpensive barrier with a oneway valve that prevents direct
mouth-to-mouth contact
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.
Emergency Suction
Laerdal V-Vac Suction Unit
replacement cartridge
Airway Obstruction
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.
http://images.webmd.com/static54/images/hwstd/medical/pulmonol/n5551303
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.
http://images.webmd.com/static54/images/hwstd/medical/pulmonol/n1573.j
pg
Head Tilt
http://www.brooksidepress.org/Products/OperationalMedicine
/DATA/operationalmed/Manuals/HM32/Chapter04/fig04-03.gif
Jaw Thrust / Chin Lift
http://www.brooksidepress.org/Products/OperationalMedicine
/DATA/operationalmed/Manuals/HM32/Chapter04/fig04-04.gif
Things that Make Mask
Ventilation More Difficult
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facial obesity
big, thick beard
large jaw
no teeth
massive facial dressings
recent nasal surgery
delicate skin
(burns, skin grafts, epidermolysis bullosa)
Langeron O, Masso E, Huraux C, Guggiari M, Bianchi A, Coriat P, Riou B:
Prediction of difficult mask ventilation. Anesthesiology 2000; 92:1229–36
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).
Oropharyngeal Airway
Nasopharyngeal Airway
Supraglottic Airway Devices
Laryngeal Mask Airway
Laryngeal Mask
Airway
Flexible
Laryngeal Mask
Proseal
Laryngeal Mask
Intubating
Laryngeal Mask
http://spaceline.usuhs.mil/current2005/11-04/parabolic_intubation.jpg
Why Intubate?
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•
•
•
•
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
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
(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.
From
Paul G. Barash,
Bruce F. Cullen,
Robert K. Stoelting
Clinical Anesthesia 2001
Intubation of obese patients can be
greatly facilitated by stacking blankets so
as to achieve the "head-elevated
laryngoscopy position” (HELP)
An Aid To Airway Management
For Obese Patients
Troop Elevation Pillow
Patent # US 6,751,818 B1
(Mercury Medical)
Normal Glottis
Photo Credit: Dr John Sherry II
Cherry Red Epiglottis
(Epiglottitis)
Photo Credit: Dr John Sherry II
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.")
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. 97:1647, 2002
http://www.nets.org.au/main/Intub1.jpg
Laryngoscopes
http://www-personal.umich.edu/~bwudcock/Guatemala/Intubation.jpg
Articulating Blade
Laryngoscopes
Flexiblade by Arco Medic Ltd.
McCoy Laryngoscope
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
12:223-225, 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 20:382-383,
1959).
http://www.adair.at/eng/museum/equip/stylets/default.htm
Trachlight
Special ETTs
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.
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.
Beck Airway-Airflow Monitor
 Magnifies airway-airflow sounds
 Activated by patient's respiration
 No moving parts
 Simple to use
 Disposable
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
Intubation Bougies
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.
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/vol%2047-4/tips984.pdf
If you can’t ventilate or
intubate, call for help and
open the neck!
Spontaneous breathing is
generally safer than
paralysis with positive
pressure ventilation by
mask, especially in cases of
airway obstruction
The “awake” airway is the
safest airway to manage
Have a low threshold for
waking up the elective
patient you are having
trouble intubating
Fiberoptic intubation is usually
ill-advised in dire emergency
cases, even with experience.
This is especially true with an
edematous, bloody airway.
If your first intubation attempt
fails ---think about what to do
differently for attempt number
two.
If you can’t intubate, ventilate!
If you cannot intubate in two or three
tries, go back to the bag-mask-valve
system and contemplate your backup
plan
If you can’t ventilate, intubate!
Patients die from failure to
oxygenate not from failure to
intubate.
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.