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