ANTICIPATION OF THE DIFFICULT AIRWAY: THE PREOPERATIVE
AIRWAY ASSESSMENT FORM AS AN EDUCATIONAL AND QUALITY
IMPROVEMENT TOOL
Carin Hagberg, M.D.Davide Cattano, M.D., Ph.D.
Jon Tyson, M.D.Funding supplied by Research in Education Grant
fromFoundation of Anesthesia Education and Research
(FAER)
DIFFICULT AIRWAY MANAGEMENT IS ONE OF THE MOST CHALLENGING TASKS FOR
ANESTHESIOLOGISTS
“There is one skill above all else that an anaesthetist is expected to exhibit and that is to maintain the airway
impeccably”
Ian Latto and Michael Rosen
DMV grossly 1 :1000
D- Laryngoscopy 10 : 100
Difficult Intubation 1 : 100
Difficult SGA management ?
Difficult Surgical Airway ?
Does the Airway Examination Prevent Difficult Intubation ?
at a minimum, a preanesthesia physical examination should include (1) an airway exam [100% consultants (72), 100% ASA members (273)]…
APSF SURVEY RESULTS IDENTIFY SAFETY ISSUES PRIORITY: AIRWAY STILL #1
Difficult Airway Management
Cost-Saving: Production Pressures
Anesthesia Delivery: Remote Sites
Anesthesia Delivery: Office-Based
Neurologic Deficit Due to Anes
Tech
Coronary Heart Disease (Pts)
Occupational Stress
Fatigue
Medication Errors
Cost-Saving: Time for Pre-op Eval
72%
62%
61%
58%
58%
56%
55%
53%
52%
52%
Stoelting RK: APSF Newsletter 1999; 14:6
WHY IS THIS STUDY IMPORTANT?
Difficult airway management pertains to every anesthesiologist
May reduce stress for both the anesthesiologist and patient
May reduce morbidity and mortality
May create a universal evaluation system
May increase overall knowledge about airway features
STUDY DESIGN – GOALS
Primary HypothesisUse of a specially designed preoperative
airway assessment form by anesthesiology residents will result in more complete documentation of important airway features (as designated by the American Society of Anesthesiologists) compared to use of the current forms
STUDY DESIGN – GOALS Secondary Hypotheses:
New preoperative form will result in greater resident recognition of patients at high risk for difficult airway as judged independently by senior anesthesiology faculty
Greater number of awake intubations by residents using the new form
Number of multiple intubation attempts and invasive surgical intubation techniques may decrease with residents using the new form
Identify and characterize features of Difficult SGD and Surgical Airway
Increased spontaneous knowledge of important airway features by 18 months for residents using the new form
Observations during the study will help refine the new form
STUDY DESIGN – PARTICIPANTS All anesthesiology residents between July 2008-
June 2010 Locations:
MHH LBJ
2 groupsGroup A
Current preoperative assessment Postoperative evaluation
Group B Current preoperative assessment New preoperative airway assessment Postoperative evaluation
Study faculty will perform independent preoperative airway assessments
Dr. Davide Cattano Dr. Carin Hagberg Dr. Sara Guzman
STUDY DESIGN – LOGISTICS
Preoperative assessments:Specialized attending and resident will be blind
to each other’s assessment Resident should review assessment with their
assigned attending
Specialized attending will page attending assigned to case when a difficult airway is anticipated
Forms must be returned to billingCompleteness/accuracy of charting will be
assessed
CURRENT PRE-OP ASSESSMENT FORMS
NEW PREOP AIRWAY ASSESSMENT FORM
5 AREAS OF DIFFICULT AIRWAY MANAGEMENT
Difficult mask ventilation
Difficult supraglottic airway
Difficult laryngoscopy
Difficult intubation
Difficult surgical airway
Mask seal (M)
BMI > 26 kg/m2
(O)
Age > 55 yrs (A)
Lack of teeth (N)
History of snoring
(S)
DIFFICULT MASK VENTILATIONPREOPERATIVE RISK FACTORS
Langeron O et al: Prediction of Difficult Mask Ventilation. ANESTHESIOLOGY 2000; 92:1229-36
Condition in which the anesthesiologist cannot provide adequate mask ventilation due to inadequate seal, excessive leak, or resistance to gas flow
DIFFICULT SUPRAGLOTTIC AIRWAY
Result of poor device placement or inability to adequately ventilate with device successfully placed
Restricted mouth opening (R)
Obstruction of upper airway (O)
Distortion/disruption of airway (D)
Stiff lungs (reduced compliance or increased resistance) (S)
DIFFICULT LARYNGOSCOPYInability to visualize any portion of the vocal cords after multiple attempts at conventional
laryngoscopy
Grade 1
Grade 2a
Grade 2b
Grade 3
Grade 4
Yentis & Lee Modification of Cormack & Lehane Classification
DIFFICULT LARYNGOSCOPY - LEMON
Look Externally
(L)
Evaluate 3-3-2
(E)
Mallampati
class (M)
Obstruction (O)
Neck mobility
(N)
Difficult Intubation A Difficult Laryngoscopy does not automatically predict a
Difficult Intubation
Difficult Intubations Can Be Skill Related
Examples of alternative techniques:
1.FOB- fogging, bleeding
2. I-LMA- mouth opening, tonsils, alignment of axis
3. Glidescope- mouth opening, cannot pass and align the ETT
Patients’ preexisting conditions:
Severe tracheal deviation
Bleeding disorders
Neck abscess
Laryngeal and subglottic
tumor
Etc.
Difficult laryngoscopy Requires multiple attempts
Easy Laryngoscopy but conditions altering the anatomy of the larynx or the trachea
AlternativeTechniques
DIFFICULT SURGICAL AIRWAY
Surgery/disrupted airway (S)
Hematoma/infection (H)
Obese/access problems (O)
Radiation/excessive bleeding (R)
Tumors (T)
Walls R, Murphy M; National Airway Course, USA
PLAN DESCRIPTION
Note how you will proceed on the form
What type of anesthesia will you administer?
Local or general?
POSTOPERATIVE EVALUATION
MASK VENTILATION
Evaluation of mask ventilation
SGA DEVICE
Evaluation of supraglottic airway device (if used)
C-L AND INTUBATIONEvaluation of
Cormack and Lehane grade on DL
Evaluation of Intubation (if performed)
SURGICAL EVALUATION
Evaluation of surgical airway (if applicable)
EXTUBATION
Evaluate extubationRegister difficult airway
(if applicable)
Errare humanum est perseverare diabolicumSeneca the Younger or Lucius Anneus Seneca (c. 4 BC – AD 65)
TO ERR IS HUMAN, TO FORGIVE IS DIVINE
Alexander Pope [21 May 1688 – 30 May 1744] english poet