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ASA GUIDELINE REVIEW Management of the Difficult
Airway
❦ Carin A. Hagberg, MDJOSEPH C. GABEL PROFESSOR & CHAIR ∣ Dept. of Anesthesiology!
THE UNIVERSITY OF TEXAS MEDICAL SCHOOL AT HOUSTON!
MEDICAL DIRECTOR ∣ Perioperative Services!MEMORIAL HERMANN HOSPITAL, HOUSTON, TX
Lecture Objectives
Review specifics of revised ASA DA guidelines!
Review basics of a preoperative airway exam!
Discuss appropriate options for CVCI situation!
Discuss appropriate options for extubation of the difficult airway!
Communication of DA to future caregivers
❦
The clinical situation in which a conventionally trained anesthesiologist experiences difficulty with FMV of the
upper airway, tracheal intubation, or both.!
Represents a complex interaction between patient factors, the clinical setting, and the skills of the practitioner.
Difficult Airway
❦
❦
APSF Survey Results Identify Safety Issues Priority
Airway Still #1Difficult Airway Management
Cost-Saving: Production Pressure
Anesthesia Delivery: Remote Sites
Anesthesia Delivery: Office-Based
Neurologic Deficit Due to Anes Touch
Coronary Heart Disease (pts)
Occupational Stress
Fatigue
Medication Errors
Cost-Saving Time for Pre-Op Eval 52
52
53
55
56
58
58
61
62
72
Stoelting RK: APSF Newsletter 1999; 14:6❦
Practice Guidelines Management of the Difficult Airway
Systematically developed recommendations that assist the practitioner in making decisions.!
Purpose to facilitate management of the DA & reduce the likelihood of adverse outcomes.!
Not intended as standards of care or absolute requirements.!
Revised & updated the 1993 publication of ASA’s guidelines for management of the DA.
❦Anesthesiology 2003 98:1269-77
☙An updated report by the ASA Task Force☙
Patient History
❦
Airway history should be conducted on all patients, if feasible.!
Intent is to detect medical, surgical, & anesthetic factors that may indicate DA.!
Examine previous MR, if available in a timely manner.
ESSENTIAL ROUTINE PREOPERATIVE AIRWAY EVALUATION
1) Length of upper incisors!
2) Involuntary: maxillary teeth anterior to mandibular teeth!
3) Voluntary: protrusion of mandibular teeth anterior to maxillary teeth - lip bite test !
4) Interincisor distance <4 cm!
5) Oropharyngeal class (MP 3 or 4)!
6) Narrowness of palate!
7) Mandibular space compliance
8) Mandibular space length!9) Length of neck!10) Head/Neck ROM!11) Thickness of neck
TMD <6 cm
SMD <12Anesthesiology 2003 98:1269-77
? >40 cm
Does the airway exam
predict difficult
intubation?
Identify patients w/ individual predictors!
Determine any combinations of predictors that may lead to difficulty!
Perform additional testing & obtain preop consultation!
Review w/ expert(s) to formulate plan for airway management!
Ability to better acurately predict should reduce number of adverse outcomes & improve safety of airway management!
❦ In Fleisher L (ed). Evidence-Based Practice of Anesthesiology. W.B. Saunders, 2004; 34-46
!Aim to identify factors that complicate DL & intubation!
100 Patients!BMI >40, elective surgery!
PreOperative Measurements:!TMD, SMD!height, weight!neck circumference, mouth opening!
Intubation Difficulties!Neither absolute obesity nor
BMI!Large neck circumference & high
Mallampati scores!
❦ Brodsky JB, Lemmens HJM, Brock-Utne JG, Vierra M, Saidman LI; Morbid Obesity & Tracheal Intubation. Anesth Analg; 2002; 94:732-6.
Neck Circumference
Other Options (not limited to)!✤ surgery (face mask, LMA anesthesia)!✤ local anesthesia infiltration!✤ regional nerve block!
Invasive Airway Access!Surgical or Percutaneous Tracheostomy or Cricothyrotomy!Alternative, Non-Invasive Approaches-DI (not limited to)!
✤ different laryngoscope blades!✤ LMA-intubating conduit (FOB optional)!✤ FOB!✤ intubating stylet or tube exchanger!✤ light wand!✤ retrograde intubation!✤ blind oral intubation!✤ blind nasal intubation!
Consider re-preparation of the patient for awake intubation or canceling surgery!
Emergency, Non-Invasive Airway Ventilation (not limited to)!
✤ rigid bronchoscope!✤ esophageal-tracheal combitube ventilation!✤ transtracheal jet ventilation
Other options include (not limited to): surgery utilizing face mask or SGA anesthesia (LMA, ILMA, laryngeal tube), local anesthesia infiltration or regional nerve blockade. Pursuit of these options usually implies that mask ventilation will not be problematic. Therefore, these options may be of limited value if this step in the algorithm has been reached via the
Emergency Pathway.
Invasive airway access includes surgical or percutaneous airway, jet ventilation, & retrograde intubation.
Alternative difficult intubation approaches include (not limited to) video-assisted laryngoscopy, alternative
laryngoscope blades, SGA (LMA, IL MA), as an intubation conduit (w/or w/out fiberoptic guidance), fiberoptic
intubation, intubating stylet or tube changer, light wand, and blind oral or nasal intubation
Consider re-preparation of the patient for awake intubation or canceling surgery
Emergency non-invasive airway ventilation consists of a SGA
Other options include (not limited to): surgery utilizing face mask or SGA anesthesia (LMA, ILMA, laryngeal tube), local anesthesia
infiltration or regional nerve blockade. Pursuit of these options usually implies that mask ventilation will not be problematic. Therefore, these options may be of limited value if this step in the algorithm has been
reached via the Emergency Pathway.
Invasive airway access includes surgical or percutaneous airway, jet ventilation, & retrograde intubation.
Alternative difficult intubation approaches include (not limited to) video-assisted laryngoscopy, alternative laryngoscope blades, SGA
(LMA, IL MA), as an intubation conduit (w/or w/out fiberoptic guidance), fiberoptic intubation, intubating stylet or tube changer, light
wand, and blind oral or nasal intubation
Consider re-preparation of the patient for awake intubation or canceling surgery
Emergency non-invasive airway ventilation consists of a SGA
Prediction of Difficult Mask Ventilation
Prospective Study (1,502 pts)!French university hospital!
DMV: inability to maintain O2 sat >92% or prevent/reverse signs of inadequate ventilation during PPMV under GA!
Reported incidence of DMV 5%!
❦ Langeron O, et al; Anesthesiology 2000; 92:1229-36
Difficult Mask Ventilation PreOperative Risk Factors
M: mask seal !O: BMI >26 kg/m2 !A: age >55 yrs !N: lack of teeth !S: history of
❦ Langeron O, et al; Prediction of Difficult Mask Ventilation. Anesthesiology 2000; 92:1229-36
Techniques for Difficult Ventilation✤ Esophageal tracheal combitube!
✤ Intratracheal jet stylet!
✤ Laryngeal mask airway!
✤ Oral & nasopharyngeal airways!
✤ Rigid ventilating bronchoscope!
✤ Invasive airway access!
✤ Transtracheal jet ventilation!
✤ Two-person mask ventilation
❦
!2 person effort!Triple airway maneuver:!
T: tilt head!A: advance mandible!M: mouth open!
Large oropharyngeal and/or nasopharyngeal airways!
❦
Optimal Attempt at BMV
Actively pursue opportunities to deliver
supplemental oxygen throughout the process of
difficult airway management
❦ Anesthesiology 2003; 98:1269-77
It is not possible to visualize any portion of the VC after multiple attempts at
conventional laryngoscopy!Incidence 1.5-3%!
Difficult Laryngoscopy
❦
Predicts easy intubation in 95% of cases!
!
!
<3% need any intubation adjuncts
grade 2bLikely to require
gum elastic bougie, but no other adjuncts
easy restricted difficult
COOK MODIFICATION!CORMACK-LEHANE CLASSIFICATION
Cook TM; Anesthesia 2000; 55:274-9
grade 1
grade 2a grade 3a grade 4
grade 3b
Associated w/ difficult
intubation in 75% of cases!
!
Specialist intubation
techniques are likely required
TROOP ELEVATION PILLOW
NISSEN IPAD
❦
“HELP” Head-elevated laryngoscopy position. Rich J. Anesth Analg 2004; 98(1):364-5
✤ Helps maximize upper airway patency!
✤ Improves mechanics of ventilation!
✤ Lengthens apneic time period to critical hypoxia in massive obesity
Tracheal intubation requires multiple attempts, in the presence or absence of tracheal pathology!
Incidence 1.2-3.8%!
Difficult Tracheal Intubation
❦
Sniffing Position
❦Oral Axis (OA), Paryngeal Axis (PA) & Laryngeal Axis
(LA) must be aligned to facilitate viewing of glottis by DI
PA
LA
OA
DL
Techniques for Difficult Intubation
!Alternative laryngoscope blades!
Awake intubation!
Blind intubation (oral/nasal)!
Fiberoptic intubation!
Intubating stylet-tube changer!
Light wand!
Retrograde intubation!
Invasive airway access!
x
Difficult Airway Algorithm
Consider the relative merits & feasibility!of 3 basic management choices:
vsAwake Intubation
Non-Invasive Technique!Initial Intubation Approach
Spontaneous Ventilation!Preservation
Intubation Attempts After!GA Induction
Spontaneous Ventilation!Ablation
Invasive Technique!Initial Intubation Approachvs
vs
❦ ASA Task Force on Management of the Difficult Airway.!Anesthesiology 2003; 98:1269-77
Difficult Airway Algorithm
Video-assisted laryngoscopy as an initial approach to intubation!
❦ ASA Task Force on Management of the Difficult Airway.!Anesthesiology 2003; 98:1269-77
Awake Intubation
Airway Secured!Surgical Access
FAILSUCCEED
Cancel Case Consider Feasibility of!Other Options
Surgical Airway
Airway Approached!Non-Surgical
Difficult Airway AlgorithmDevelop primary & alternative strategies!
❦ ASA Task Force on Management of the DA.!Anesthesiology 2003; 98:1269-77
Initial Intubation Attempts
UNSUCCESSFULSUCCESSFUL
Intubation Attempt After GA
❦
Face Mask !Ventilation!Adequate
Face Mask Ventilation Inadequate
Anesthesiology 2013; 118:251-70
Consider/Attempt LMA
Adequate Inadequate
EMERGENCY PATHWAYNON-EMERGENCY!PATHWAY
Alternative Approaches to Intubation
FAIL!After Multiple Attempts
Invasive Airway Access
Consider Feasibility of!Other Options
Awaken Patient
SUCCEED
Non-Emergency PathwayPatient Anesthetized, Intubation Unsuccessful!
❦ Anesthesiology 2013; 118:251-70
Mask Ventilation Adequate
Alternative Approaches to Intubation Fail After Multiple
Attempts
Invasive airway access includes:!✤ Surgical or percutaneous
trachesotomy or cricothyrotomy!
Other options include (not limited to)!✤ Surgery utilizing face mask or
LMA anesthesia!✤ LA infiltration!✤ Regional nerve block!
Consider re-preparation of the other patient for awake intubation or canceling surgery!
❦
DIFFICULT AIRWAY (DA) RECOGNIZED
Surgery Can Be Done Under Regional Anesthesia (RA)
Surgery Can Be Quickly Terminated
Surgery Cannot Be Quickly Terminated
All Patient Positions (access to airway not important)
Good Access to Airway, Patient Agrees to Awake
TI if RA Fails
Poor Access to Airway
RA Acceptable
RA Acceptable
RA Unacceptable
RA Fails
Awake TICancel Case
GA
Redo RA
RA Fails
Patient Remains Cooperative
Awake TI
GA
Patient is Not Cooperative
ASA DA Algorithm
GA with Plan B Ready to Go
DA=Difficult Airway
RA=Regional Anesthesia
GA=General Anesthesia
TI=Tracheal Intubation
In Benumof JL (ed): Airway Management Principles and Practice. St. Louis, Mosby-Year Book, 1996, 150.
❦Beware of the inexperienced, ambitious clinician, who offers to help.
❦
Emergency Pathway
Options for emergency, non-invasive airway ventilation include (not limited to): rigid bronchoscope, Combitube, TTJ, LMA ventilation
LMA & Combitube✤ Both will likely work as
ventilatory mechanisms!
✤ Both can be inserted blindly!
✤ Few complications w/their use!
✤ Combitube often unfamiliar & unavailable!
✤ Proseal & other SGA’s!
✤ Consideration of intubation conduit
Non-Pathological✤ Natural anatomy!
- Tongue!✤ Supralaryngeal ventilatory mechanism!
- LMA, etc!- Other alternative SLA
Pathological✤ Abnormal anatomy!
- Cancer!- Hematoma!- Abscess!- Edema!
✤ Subglottic ventilatory mechanism!
- Rigid bronch, TTJV!- Surgical airway
Airway Obstruction
Rigid Bronchoscopy!Able to ventilate below
obstruction!
Inexperienced!
Risk of trauma to posterior wall of trachea!
Often unavailable
Comparison of Flexible Fiberscope & Rigid Bronchoscope
❦ Rudolph C, et al; Minerva Anestesiol 2007; 73:567-74
FF RBIPreparation time Longer ShorterVisualization of tube passage No YesSuccess rate of intubation High HighMechanical strength Lower HigherEndoscopic orientation Poorer BetterIntegrated suction channel Yes NoRetromolar route No YesNasal route Yes NoMobile light source (battery, adapter)
Available AvailableLearning curve Flatter SteeperCosts (acquisition, repair) Higher Lower
Retrograde IntubationØ Techniques include classic, silk ,
guide wire, and FOB!!Ø Safe, effective and fast when
technique is familiar !!Ø Useful whenever anatomic
limitations obscure glottic opening (pathology, CSI, upper airway trauma)!!
Ø CAN VENTILATE situations
Transtracheal Jet VentilationØ May be performed via a
catheter (cric or AEC) or via a bronchoscope (rigid or flexible)!
!Ø Technique varies with type of
procedure!!Ø Vigilance is of the essence!!Ø OPEN THE AIRWAY !!!!
Transtracheal Jet Ventilation
Often unavailable!
Used innappropriately!
Significant risk of barotrauma!✤ Too large TV!✤ Too short exhalation
phase!✤ Catheter dislodgement!
!
CricothyrotomyØ Final CVCI option in ALL airway
algorithms!
Ø Life-saving technique that should be mastered!
Ø Methods include needle, percutaneous, and surgical!
Ø Universal cricothyrotomy catheter set!
Cuffed airway catheter and instrumentation for both wire-guided and surgical techniques
Curved blunt dilator
Tracheal hook
Trousseau tracheal dilator
Surgical Technique First Choice
Laryngeal/tracheal disruption!
Upper airway abscess or obstruction!
Combined mandibular maxillary fractures
Extubation & ASA Task Force
Recommendations
Consider relative merits of awake vs. deep extubation!
Evaluate factors that may interfere w/upper airway
patency!
Formulate a plan for immediate reintubation if
the airway becomes compromised!
Consider a jet stylet
❦ Anesthesiology 2003; 98:1269-77
Standard Approaches✤ Awake extubation!
✤ Anesthetized (deep) extubation!
✤ Extubating after positive “cuff leak test”!
✤ Extubating when expert help is available
Important ConsiderationsSetting & Circumstances!
Surgical Procedure!
Type of anesthetic!
Cardiorespiratory stability!
Underlying patient disease!
Establishment of present airway❦
❦ Lorraine Foley, MD, Tufts Medical School
Anticipate the possibility of DA management by performance of a thorough pre-op airway assessment!
Secure the airway awake if difficulty is suspected!
Have a back-up plan(s) if the initial plan to secure the airway fails
ASA Difficult Airway Algorithm Take Home Messages
Experience Matters.
Take Home PointsAlgorithms serve only as guidelines!
Equipment must be available!
Become educated!
Practice, practice, practice!!!
Do what works BEST for you!
You can make a difference!!
