Difficult airway management

The Difficult Airway
ASIF A. SABERI, MD, FCCP
PULMONARY & CRITICAL CARE MEDICINE

Objectives:
!   1. Identify the situation where a difficult airway should be
anticipated

!   2. Become familiar with approach to a the difficult airway

!   3. Discuss an algorithmic approach to a difficult airway

!   4. Discuss some key and frequently used tools for managing
the difficult airway?

Disclosure
!   No conflicts

!   I will be discussing some products

!   No financial interests or conflict

How big is the problem?
!   NEAR project: 9000 ED
!   5% airway method other than first choice
!   0.9% Surgical airway

!   J Emerg Med. 2002;22(1):31
!   30% ED intubations ‘difficult’: variations based upon expertise and
experience

!   Anesthesiology. 2011;114(1):42.
!   Of 3423 patients, 351 (10%) had a Cormack-Lehane grade 3 or 4.

!   Can J Anaesth. 2005;52(6):634.
!   OR: 5% Grade 3; <1% grade 4.

!   ED/ICU: much higher

How big is the problem?
!   Difficult BMV:
!   Anesthesiology. 2000;92(5):1229.
!   5% patient

!   Difficult Cricothyrotomy
!   Unknown

!   Extra-glottic airways (LMAs, combitubes)
!   Unknown

Consequences

100%

80%

60%

40%

20%

0%
1 attempt 2 attempts 3 attempts 4+

Hypoxemia Esoph Intub Regurg/Asp

Anesth Analg 2004;99:607–13

Cardiac arrest asystole, bradycardia, or dysrhythmia w/nonmeasurable MAP & CPR during or after w/in intubation
(5 min).
HR ϭ heart rate; SBP ϭ systolic blood pressure; MAP ϭ mean arterial blood pressure; Spo2 ϭ pulse oximetry saturation; CPR ϭ cardiopulmonary

Intubation by indications
resuscitation; ETT ϭ endotracheal tube.

Table 2. Hospital Location and Complication Risk Ratio Compared to Other Areas
Hospital location % patients Complications P-value, risk ratio (95% CI)
Surgical ICU (32 beds) 27 bradycardia Ͻ0.04, 1.5 (1.1–2.2)
Medical ICU (16 beds) 21 regurgitation Ͻ0.004, 1.9 (1.2–2.9)
Floor 16 aspiration Ͻ0.002, 3 (1.6–5.7)
Neurosurgical/trauma ICU (10 beds) 12 hypoxemia Ͻ0.03, 0.6 (.43–93)
Emergency department 10 hypoxemia Ͻ0.001, 1.7 (1.7–2.2)
Coronary ICU (12 beds) 9
Radiology/cardiac catheterization/PACU 5
ICU ϭ intensive care unit; PACU ϭ postanesthesia care unit.

Table 3. Primary Disease Leading to Intubation and Intubation Attempts
Primary disease category % patients 2 or fewer attempts (%) Ͼ2 attempts (%)
All groups combined 90 10
Cardiac (CHF, MI, arrhythmia) 28 93.2 6.8
Pulmonary (pneumonia, aspiration, COPD, secretions) 24 89.8 10.2
Sepsis-SIRS (pulmonary, abdominal, misc.) 16 93.7 6.7
Neurosurgical/neurological (CVA, seizure, trauma) 14 86.9 13.1*
Trauma 12 87.8 13.9*
Metabolic (DKA, renal or liver failure, OD) 4 90.2 9.8
GI bleeding 2 85.9 14.1*
MI ϭ myocardial infarction; CHF ϭ congestive heart failure; COPD ϭ chronic obstructive pulmonary disease; Misc. ϭ miscellaneous; CVA ϭ cerebral vascular
event; DKA ϭ diabetic ketoacidosis; GI ϭ gastrointestinal; SIRS ϭ systemic inflammatory response syndrome; OD ϭ over dose.
* P Ͻ 0.03 when compared with sepsis and cardiac groups.

Table 4. Methods of Patient Preparation
Medication % patients
Topical local anesthetic or nothing 17
Thiopental (0.5–5 mg/kg, 75–500 mg) 10
Midazolam (0.02–0.12 mg/kg, 1–9 mg) 27
Midazolam & morphine (0.02–0.07 mg/kg of each, 2–5 mg each) 6
Morphine (0.04–0.1 mg/kg, 2–8 mg) or fentanyl (50–150 ␮g) 7
Etomidate (0.04–0.25 mg/kg, 4–24 mg) 27

Hypertension SBP Ͼ160 if Ͼ20% increase from baseline
Hypoxemia Spo2 Ͻ90% during intubation attempt (profound Ͻ70%)
Regurgitation gastric contents which required suction removal during laryngoscopy in a previously clear airway
Aspiration visualization of newly regurgitated gastric contents below glottis or suction removal of contents via
the ETT
Cardiac arrest asystole, bradycardia, or dysrhythmia w/nonmeasurable MAP & CPR during or after w/in intubation
(5 min).
HR ϭ heart rate; SBP ϭ systolic blood pressure; MAP ϭ mean arterial blood pressure; Spo2 ϭ pulse oximetry saturation; CPR ϭ cardiopulmonary
resuscitation; ETT ϭ endotracheal tube.

Table 2. Hospital Location and Complication Risk Ratio Compared to Other Areas
Hospital location % patients Complications P-value, risk ratio (95% CI)
Surgical ICU (32 beds) 27 bradycardia Ͻ0.04, 1.5 (1.1–2.2)
Medical ICU (16 beds) 21 regurgitation Ͻ0.004, 1.9 (1.2–2.9)
Floor 16 aspiration Ͻ0.002, 3 (1.6–5.7)
Neurosurgical/trauma ICU (10 beds) 12 hypoxemia Ͻ0.03, 0.6 (.43–93)
Emergency department 10 hypoxemia Ͻ0.001, 1.7 (1.7–2.2)
Coronary ICU (12 beds) 9
Radiology/cardiac catheterization/PACU 5
ICU ϭ intensive care unit; PACU ϭ postanesthesia care unit.

Table 3. Primary Disease Leading to Intubation and Intubation Attempts
Primary disease category % patients 2 or fewer attempts (%) Ͼ2 attempts (%)
Trauma 12 87.8 13.9*

Trauma 12 87.8 13.9*
GI bleeding 2 85.9 14.1*
MI ϭ myocardial infarction; CHF ϭ congestive heart failure; COPD ϭ chronic obstructive pulmonary disease; Misc. ϭ miscellaneous; CVA ϭ cerebral vascular
event; DKA ϭ diabetic ketoacidosis; GI ϭ gastrointestinal; SIRS ϭ systemic inflammatory response syndrome; OD ϭ over dose.
* P Ͻ 0.03 when compared with sepsis and cardiac groups.

Table 4. Methods of Patient Preparation
Medication % patients
Topical local anesthetic or nothing 17
Thiopental (0.5–5 mg/kg, 75–500 mg) 10
Midazolam (0.02–0.12 mg/kg, 1–9 mg) 27
Midazolam & morphine (0.02–0.07 mg/kg of each, 2–5 mg each) 6
Morphine (0.04–0.1 mg/kg, 2–8 mg) or fentanyl (50–150 ␮g) 7
Etomidate (0.04–0.25 mg/kg, 4–24 mg) 27
Propofol (0.5–1.9 mg/kg, 40–240 mg) 4
Diazepam (0.05–0.12 mg/kg, 5–10 mg), methohexital (0.3–1.2 mg/kg, 30–130 mg) 2
Muscle relaxant
depolarizer-succinylcholine (81% of total use) 20
nondepolarizer-vecuronium, rocuronium (19% of total use)

from 16 to 98 yr old (mean, 68.71 yr; median, 67 Ϯ 17.5 The immediate availability of advanced airway equip-
yr), with a sex distribution of 62:38 men:women. The ment was nearly nonexistent before 1995, and there-
location of the airway procedure is listed in Table 2. after, portable airway bags were made available with

Evaluation:
Looking out for the
Difficult Airway

Morphological Red-flags
!   Length of upper incisors !   Shape of palate
!   Relation of maxillary and !   Compliance of mandibular
mandibular incisors during space
normal jaw closure
! Thyromental distance
!   Relation of maxillary and
mandibular incisors during !   Length of neck
voluntary protrusion of
mandible over the maxilla !   Thickness of neck

!   Inter-incisor distance !   Range of motion of head
and neck
!   Visibility of uvula

L.E.M.O.N.
!  Look externally
!  Evaluate 3-3-2 rule
! Mallampati Score
!  Obstruction
!  Neck Mobility
Emerg Med J. 2005;22(2):99.

L.E.M.O.N.
!  Look externally
!   Abnormal facies
!   Facial hair
!   Morbid obesity
!   Dentition
!   Tongue
!   Facial/neck trauma

L.E.M.O.N.
!  Evaluate 3-3-2 rule
!   Mouth opening: 3 fingers
!   Tip of chin to thyroid: 3 fingers
!   Thyroid-hyoid distance: 2 finger

L.E.M.O.N.
!  Modified Mallampati Score

Anesth Analg. 2006;102(6):1867.

Br J Anaesth. 2011 Nov;107(5):659-67. Epub 2011 Sep 26.

L.E.M.O.N.
!  Obstruction
!   Burns
!   Laryngeal trauma
!   Swelling/edema:
!   Prior intubation
!   Angioedema
!   Foreign body

L.E.M.O.N.
!  Neck Mobility
!   Sniffing position
!   Elevate the HOB
!   Neck trauma

Difficulty with B.M.V.:
M.O.A.N.S.
!   M: Mask Seal

!   O: Obstruction/Obesity

!   A: Age

!   N: No teeth

!   S: Stiffness

M.O.A.N.S.
!   M: Mask Seal
!   Facial hair
!   Bleeding
!   Vomitus
! Facies

M.O.A.N.S.
!   O: Obstruction/Obesity
!   Obesity, BMI > 26
!   Pregnancy
!   Pulmonary edema
!   Secretions
!   Reverse Trendelenberg

M.O.A.N.S.
!   A: Age
!   Lack of elasticity
!   ?Age cut off

!   N: No teeth
!   Edentulousness

!   S: Stiffness

Difficult Cricothyrotomy
!   Access to anterior neck

!   Difficult landmarks

!   Anatomical distortion

!   Obesity, women

Difficult Extra-glottic airway:
R.O.D.S.
!   Restricted mouth opening

!   Obstruction

!   Disruption, distortion, debris

!   Stiff lung or cervical spine

Difficult airway management

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