1. Five New Devices for the Difficult Airway
Ron M. Walls, MD
Brigham and Women’s Hospital
Harvard Medical School
The Difficult Airway

2. A Haiku Can’t intubate, can’t ventilate…Panic. Flail. Brain Cells
New Devices for the Difficult Airway
A Haiku
Can’t intubate, can’t
ventilate…Panic. Flail. Brain Cells
die in bunches.
The Difficult Airway

3. New Devices for the Difficult Airway
Outline
Magnitude of the problem
Where do new devices fit in?
New devices
The Difficult Airway

4. Difficult Laryngoscopy: Cormack-Lehane Score
The Difficult Airway

5. New Devices for the Difficult Airway
Magnitude of the Problem: OR
Grade 3 or 4 laryngoscopy < 5%
True grade 4 laryngoscopy < 1%
Impossible intubation 0.35% of “normals”
“CICV” ~ 1:10,000 or 0.01%
Patients are “pre-selected”
NOT applicable to ED or out-of-hospital intubations
Cormack, Karkouti, Langeron, Mallampati, Samsoon, Williams, Wilson, others
The Difficult Airway

6. How common is difficult bag mask ventilation?
In the OR (patients are pre-selected)
Difficult BMV in %
Impossible BMV in 0.16%
Difficult BMV with difficult intubation in ~ 0.3% to 5%
Difficult BMV makes DI 4x more common, and impossible intubation 12x
Numbers not known for the ED, EMS
Langeron O et al. Anesthesiology 2000 May
Kheterpal S et al. Anesthesiology 2006 Nov; 105:
The Difficult Airway

7. New Devices for the Difficult Airway
Outline
Magnitude of the problem
Where do new devices fit in?
New devices
The Difficult Airway

8. Where do new devices fit in?
Historically considered novelties, “toys”
Reserved for difficult, failed airways
Late adopters vs early adopters
The real question is…
The Difficult Airway

9. Where do new devices fit in?
If you had trained on, and used, a video laryngoscope, or a fiberoptic stylet, and DL was newly introduced:
What would the studies show?
Would you adopt the new technology?
Would the lower cost matter?
The Difficult Airway

10. Where do new devices fit in?
If you had trained on, and used, a video laryngoscope, or a fiberoptic stylet, and DL was newly introduced:
The studies? Clear inferiority!
Would you adopt? No!
Would the lower cost matter? No!
The Difficult Airway

11. Where do new devices fit in?
These are “every intubation” devices
There is a learning curve
The question is not whether, but which, and when?
The Difficult Airway

12. New Devices for the Difficult Airway
Outline
Magnitude of the problem
Where do new devices fit in?
New devices
The Difficult Airway

13. The future of difficult laryngoscopy?
All difficult laryngoscopy definitions are based on direct laryngoscopy
Most have to do with impossibility of creating “a line of sight”
Video laryngoscopes will require an entirely new way of thinking
The Difficult Airway

14. New Devices for the Difficult Airway
Glidescope
Video laryngoscope
Minimal mouth opening required
Very high intubation success rate
Allows “teacher” to share view with “student”
Portable, durable
The Difficult Airway

15. New Devices for the Difficult Airway
Glidescope
The Difficult Airway

16. How good is the Glidescope?
The Difficult Airway

17. Is there a learning curve?
728 patients, 133 operators, 18 months
133/728 had DL and GVL – GVL always equal or better view
35 with grade III/IV with DL; 24/35 better with GVL
Failure 26/728 (3.6%), 14/26 had grade I views
Cooper RM: Can J Anaesth 52:191, 2005.
The Difficult Airway

18. For Routine Airways ? DL then GL on 400 elective anesth patients
DL: 67%, 26%, 6%, 0.5% grades I-IV
GL: 89.5%, 10.5%, 0%, 0%
Success GL: 85.5%, 97.5%, 99.9% att 1-3
All <40 secs, mean 21 secs
1/400 not intubated despite Grade I view
Tremblay M-H et al. Anesth Analg 2008 May; 106:1495.
The Difficult Airway

19. For Novices ?
20 novice clinicians (paramedic students, PGY1 residents, nurses, med students)
Demo then 3 successful intubations with DL and GVL on manikins
200 patients (5+5 each)
93% vs 51% success in <120 secs
CL III/IV 8% vs 50%.
Time 63 secs vs 89 secs
Nouruzi-Sedeh P: Anesthesiology 110:32, 2009
The Difficult Airway

20. For C-Spine Injury ? 20 elective anesth patients with ILS
2 anesth residents with 30x experience
Continuous fluoro
CSpine movement comparable
Grade 1: 50% v 0%, 2: 50% v 65%, 3: 0% v 35%
Robitaille A: Anesth Analg 106:935, 2008.
The Difficult Airway

21. Is there a learning curve?
728 patients, 133 operators, 18 months
133/728 had DL and GVL – GVL always equal or better view
35 with grade III/IV with DL; 24/35 better with GVL
Failure 26/728 (3.6%), 14/26 had grade I views
Cooper RM: Can J Anaesth 52:191, 2005.
The Difficult Airway

22. McGrath Videolaryngoscope
Videoscope with built in screen
Blade design similar to GS
Plastic sheath for blade
Blade adjustable
The Difficult Airway

23. McGrath in Clinical Studies
Mostly case series and reports
143/150 patients Grade I, 6 Grade 2
98% intubation success
No comparison studies (yet)
Shippey B: British Journal of Anaesthesia (1):
Shippey B: Can J Anaesth 2007; 54:
The Difficult Airway

24. Storz Video Laryngoscope
Video/FO laryngoscope
Based on standard blades
Interchangeable video camera system
Pediatric and adult blades
High quality optics
The Difficult Airway

25. Storz CMAC® (now released)
The Difficult Airway

26. CMAC vs Storz VL Storz VL is fiberoptic coupled to CCD video
CMAC is “pure” CMOS video
Fogging vs no fogging
Two cables vs one
Expense
Complexity
Image quality
The Difficult Airway

27. How good is the Storz VL? 54 patients have DL and SVL by exp anesth
7x greater force on maxillary incisers DL vs SVL
17% grade III/IV vs 0%
Lee RA: Anesth Analg 108:187, 2009.
The Difficult Airway

28. For learning ?
49 novice intubators on manikins with normal or Diff Airways, DL vs SVL
84% vs 54% first attempt success
Less dental trauma
Greater confidence, considered intubation less difficult than DL group
Low D: Anaesthesia 63:195, 2008
The Difficult Airway

29. Pentax AWS® (not yet released in the US)
Videoscope with preload tube channel
Lenticle helps aim
Light, portable
The Difficult Airway

30. How good is the Pentax AWS?
Better view, less CS movement than MAC
46/320 patients grade III/IV with MAC:
45 Grade I, 1 Grade IIa with AWS
IDS with AWS 0 in 305, 1 in 14, 2 in 1
Decreased CS movement with bougie
Enomoto Y: British Journal of Anaesthesia (4):
Suzuki A: Anaesthesia. 63(6): , June 2008.
Takenaka I: Anesthesiology 110: , June 2009.
The Difficult Airway

31. Fiberoptic Stylets Storz Bonfils® Clarus Shikani Optical Stylet®
Clarus Levitan® Stylet
AirRIFL®
All (except Levitan) avoid DL
Rigid, + malleable
Like lighted stylet, but “visual”
Portable, have own light source
The Difficult Airway

32. SOS Malleable FO Midline approach Inexpensive Video adaptable
The Difficult Airway

33. SOS 55% less C-Spine movement than MAC DL 28 vs 17 seconds to intubate
Better and faster than DL + bougie in manikin model
Case reports, small series in children
Turkstra TP et al. Can J Anesth 54:441; 2007.
Evans A et al: Anaesthesia 61:478; 2006.
The Difficult Airway

34. Air RIFL® New dynamically adjustable FO stylet Little/no research data
No real clinical experience (yet)
Cool entrepreneurial website, though
The Difficult Airway

35. Bonfils Stylet Non-malleable Retro-molar approach Popular in N Europe
Self contained
High quality optics
Higher price than SOS
The Difficult Airway

36. New Devices for the Difficult Airway
AirTraq®
“Periscope”
Mounted tube
Disposable
Maharaj CH et al., Anesthesiology 2007 Jul; 107:53-9.
Maharaj CH et al., Anaesthesia 2008 Feb; 63:182.
Hirabayashi Y et al., Anaesthesia 2008 Jun; 63:635.
The Difficult Airway

37. Take home points? VL is superior to DL Shorter learning curve
Better glottic views
Equal or better on virtually every measure
So, what is holding us back?
The Difficult Airway

38. The Difficult Airway

39. And the Venerable Laryngoscope?
The Difficult Airway

40. Prediction By 2010, a minority of ED intubations will be done
New Devices for the Difficult Airway
Prediction
By 2010, a minority of
ED intubations will be done
using a conventional
laryngoscope and blade.
The Difficult Airway

41. New Devices for the Difficult Airway ventilate. Knew in advance.
Another Haiku
Can’t intubate. Can’t
ventilate. Knew in advance.
Plan rescues the life.
The Difficult Airway

42. The Difficult Airway
FIN
The Difficult Airway