Extubation of the difficult airway

1. Extubation of the difficult airway
Helga Komen, MD
Department of Anesthesiology
Washington University in St Louis Medical School

2. …How big is a problem?
• In claims for injuries due to inadequate
airway management, respiratory adverse
events causing death or brain damage at
induction of anesthesia have decreased over
the past years, while tracheal extubation
and/or recovery are still associated with an
unchanged rate of death or brain damage,
suggesting that education and guidance in
this area are still needed.
Peterson 2005, Langeron 2006.

3. GN Peterson Anesthesiology, 2005, 103:33-39.

4. Among claims for failed extubation
reported since 2000, death and
permanent brain damage occurred in 15
of 16 claims (94%), and there were 8
claims with difficult airway management
that occurred post-extubation in the
recovery period, all (100%) resulting in
death/brain damage.
Personal communication from Karen Posner PhD—Laura Cheney Professor in Anesthesia
Patient Safety, Department of Anesthesiology, University of Washington on November 10, 2011

5. Definition/s
• Extubation failure – inability to tolerate removal of
the translaryngeal tube
– Mechanisms – airway obstruction due to laryngospasm,
upper airway edema, bleeding, secretions, tracheal
colapse, opioids, muscle relaxants
• At-Risk Extubation – the ability of patient to maintain airway
patency and/or oxygenation after tracheal extubation is
uncertain
• Difficult extubation - `difficult decanulation of the airway`
• Weaning failure – inability to tolerate spontaneous breathing
without ventilatory support

6. • Extubation failure
– Early reintubation – mins up to 6 hours after
extubation (most frequently 0-2 hrs, it is rare….0.1-
0.45%)
• Resp. Insufficiency, airway obstruction (laryngeal edema),
bronchospasm, prolonged neuromuscular blockade, side effects of
opioids
– Late reintubation – events occurring between 6
and 72 hours after extubation
Definition/s
Cavallone L, Anesth Analg 2013;116(2):368-83

7. …at increased risk for extubation failure
• Obesity/OSA
– BMI >30kg/m2 (34% of population)
– ↑incidence of difficult mask ventilation
– ↑risk of pulmonary aspiration
– ↑airway obstruction
– ↑rapid oxygen desaturation
– Postop concerns:
• Opioids vs. resp. depression, hypoxia, patient positioning,
adequate monitoring
– ↑major airway complications

8. • Head and neck pathology/surgery
– Reintubation rate 0.7-11.1%
• Obstetrics – edema of the airway, obesity
• Cervical spine surgery (anterior) - >5hrs, >3 vertebral
levels, >300ml blood loss. !! Close respiratory
monitoring up to 48hrs.
– Pharyngeal edema, vocal cord paralysis, hematoma
…at increased risk for extubation failure

9. Causes and mechanisms of extubation failure
• Pharyngeal obstruction – mismatch between bony/soft tissue
amount, ↓tension of pharyngeal wall, retropharyngeal
hematoma, secretions
• Laryngeal obstruction – edema, laryngospasm (contraction of
adductor muscles of vocal cords) – NPPE! (0.1%), vocal cord
paralysis (uni-, bil-)
• Postoperative bleeding – hematoma compressing airway
• Masses and lesions - mediastinal
• Drugs – opioids, muscl. blockade

10. So, how to avoid extubation failure?!
• Current recommendations
– ASA, Anesthesiology, 2013.
• Practice Guidelines for Management of the Difficult
Airway - An Updated Report by the American Society of
Anesthesiologists Task Force on Management of the
Difficult Airway
– DAS, Anesthesia, 2012.
• Difficult Airway Society Guidelines for the
management of tracheal extubation

11. ASA guidelines 2013.
Anesthesiology 2013;118:1-20

12. ASA guidelines 2013.
Strategy for Extubation of the Difficult Airway
• The literature does not provide a sufficient basis for
evaluating the benefits of an extubation strategy for
the difficult airway.
– For the purpose of this Guideline, an extubation strategy is
considered to be a logical extension of the intubation
strategy.

13. Recommendations
• The anesthesiologist should have a pre-formulated
strategy for extubation of the difficult airway.
• This strategy will depend, in part, on the surgery, the
condition of the patient, and the skills and
preferences of the anesthesiologist.
ASA guidelines 2013.

14. The preformulated extubation strategy should include:
1. A consideration of the relative merits of awake extubation versus extubation
before the return of consciousness.
2. An evaluation for general clinical factors that may produce an adverse
impact on ventilation after the patient has been extubated.
3. The formulation of an airway management plan that can be implemented if the
patient is not able to maintain adequate ventilation after extubation.
4. A consideration of the short-term use of a device that can serve as a guide for
expedited reintubation. This type of device can be a stylet (intubating bougie) or
conduit.
- Stylets or intubating bougies are usually inserted through the lumen of the tracheal tube and into the
trachea before the tracheal tube is removed. […] Conduits are usually inserted through the mouth and
can be used for supraglottic ventilation and intubation The ILMA and LMA are examples of conduit.
ASA guidelines 2013.

15. Pros and cons of awake versus asleep
extubation
Fully awake
• Pros = complete recovery of airway protective reflexes and effective
spont. breathing are present and may increase safety in the
presence of possible difficult re-intubation.
• Cons = active protective airway reflexes may lead to increased risk
of re-bleeding at the site of surgery (increased venous pressure and
straining on wound).
• Caveats= if pt. awake but NOT calm and cooperative, safe
extubation procedures (e.g. flexible laryngoscopy, correct
positioning of tube exchanger) may be extremely difficult…

16. Pros and cons of awake versus asleep
extubation
Asleep (regular and effective spont. breathing must be
present)
• Pros = pt still anesthetized avoids coughing and fighting ventilator which
would lead to increased risk of re-bleeding at the site of surgery (due to
increased venous pressure and straining on sutures.)
• Cons = lack/decrease of protective airway reflexes may lead to increased
risk for aspiration and airway obstruction;
• Caveats= easy pre-operative intubation and mask ventilation are
important prerequisites; increased risk of laryngospasm if performed
during transition between deep anesthetized state and awake state…

17. Should I even consider asleep (deep)
extubation?
ASA: consider the relative merits…
DAS: Deep extubation is a technique that should be
reserved for spontaneously breathing patients with
uncomplicated airways and only performed by
clinicians familiar with the technique.

18. The preformulated extubation strategy should include:
1. A consideration of the relative merits of awake extubation versus extubation
before the return of consciousness.
2. An evaluation for general clinical factors that may produce an adverse
impact on ventilation after the patient has been extubated.
3. The formulation of an airway management plan that can be implemented if the
patient is not able to maintain adequate ventilation after extubation.
4. A consideration of the short-term use of a device that can serve as a guide for
expedited reintubation. This type of device can be a stylet (intubating bougie) or
conduit.
- Stylets or intubating bougies are usually inserted through the lumen of the tracheal tube and into the
trachea before the tracheal tube is removed. […] Conduits are usually inserted through the mouth and
can be used for supraglottic ventilation and intubation The ILMA and LMA are examples of conduit.
ASA guidelines 2013.

19. How do we perform a quantitative cuff-leak test?
Pt. mechanically ventilated with CMV:
1) measurements of expiratory tidal volumes
after 4-6 complete respiratory cycles with the
ETT cuff deflated
2) measurements of expiratory tidal volumes
with cuff deflated ONLY at the end of the
end-inspiratory pause.
G Prinianakis et al “Determinants of the cuff-leak test: a physiological study”
Critical Care 2005, 9: R24-R31
Miller RL, Chest 1996;110:1035-40
RS Sandhu et al. J Am Coll Surg 2000; 190/6: 682-687.
S Jaber et al. Intensive Care Med 2003; 29:69-74
D De Backer Critical Care 2005;9:31-33

20. How much should the leak be?
Proposed cut-off values in the literature:
• 10-12% of the TV that was measured before cuff deflation
(average-adult population)
• 110-130 ml (average – adult population)
Miller RL, Chest 1996;110:1035-40
RS Sandhu et al. J Am Coll Surg 2000; 190/6: 682-687.
S Jaber et al. Intensive Care Med 2003; 29:69-74
D De Backer Critical Care 2005;9:31-33

21. How much should the leak be?
Positive and Negative predictive value of the test:
• cuff leak < 110 ml = 0.80 PPV for post-extubation stridor
(predicts presence of stridor in 80% of pts)
• cuff leak > 110 ml = 0.98 NPV for post-extubation stridor
(predicts absence of stridor in 98% of pts)
RL Miller et al. “Association between reduced cuff leak volume and postextubation Stridor”
Chest /110/4/October, 1996, 1035-1040. Miller RL, Chest 1996;110:1035-40

22. The preformulated extubation strategy should include:
1. A consideration of the relative merits of awake extubation versus extubation
before the return of consciousness.
2. An evaluation for general clinical factors that may produce an adverse
impact on ventilation after the patient has been extubated.
3. The formulation of an airway management plan that can be implemented if the
patient is not able to maintain adequate ventilation after extubation.
4. A consideration of the short-term use of a device that can serve as a guide for
expedited reintubation. This type of device can be a stylet (intubating bougie) or
conduit.
- Stylets or intubating bougies are usually inserted through the lumen of the tracheal tube and into the
trachea before the tracheal tube is removed. […] Conduits are usually inserted through the mouth and
can be used for supraglottic ventilation and intubation The ILMA and LMA are examples of conduit.
ASA guidelines 2013.

23. Options?
• Reintubation ? (…over an AEC)
• Supra-glottic airway? (for
ventilation/reintubation)
• Tracheostomy? (if swelling expected to be
persistent…)

24. The preformulated extubation strategy should include:
1. A consideration of the relative merits of awake extubation versus extubation
before the return of consciousness.
2. An evaluation for general clinical factors that may produce an adverse
impact on ventilation after the patient has been extubated.
3. The formulation of an airway management plan that can be implemented if the
patient is not able to maintain adequate ventilation after extubation.
4. A consideration of the short-term use of a device that can serve as a guide for
expedited reintubation. This type of device can be a stylet (intubating bougie) or
conduit.
- Stylets or intubating bougies are usually inserted through the lumen of the tracheal tube and into the
trachea before the tracheal tube is removed. […] Conduits are usually inserted through the mouth and
can be used for supraglottic ventilation and intubation The ILMA and LMA are examples of conduit.
ASA guidelines 2013.

25. 11.0 Fr; L = 100 cm; ID = 2.3 mm
14.0 Fr; L = 100 cm; ID =3.0 mm
19.0 Fr; L= 56 cm; ID = 4.7 mm

26. Thomas C. Mort, Anesth Analg 2007; 105(5):1357-62.

27. Should a patient with an AEC in situ decompensate,
tracheal re-intubation is the key management strategy.
Supplemental oxygen can be
provided using standard techniques
prior to intubation.
Oxygen insufflation through an AEC appears to be associated
with a lower risk of volutrauma or barotrauma, but […] it is not
risk-free.
L Duggan, Can J Anesth/J Can Anesth (2011) 58:560–568
Use AEC for re-intubation

28. DAS guidelines 2012.
Anaesthesia. 2012 Mar;67(3):318-40

32. Specialty guidelines?
• OSA/Obese patients
• Head and Neck

33. Specific strategies for extubation of
OSA/obese patients
Seet E, Chung F. Can J Anesth (2010) 57:849-864.
Gross JB, Bachenberg KL, Benumof JL et al. Anesthesiology (2006) 104:1081-93

34. Head and
neck
surgery
IARS Meeting, Vancouver, CA, May 2011

35. Conclusions
• Extubation failure may lead to fatal outcomes
• Situations at risk are frequently recognizable
• Official Guidelines for extubation of difficult
airway
– ASA 2013.
– DAS 2012.
• Absence of large randomized trials (only expert opinions)

36. THANK YOU!