1. The Difficult Airway: What to do when @*%% hits the fan!!
Adam Davidson
Grand Rounds
March 19th, 2009

2. The Reality
3-5% of academic ED intubations involve more than 3 attempts and of those, 80% are intubated with standard laryngoscopy1
Success rates approaching 99% with RSI and direct laryngoscopy1
7 out of 6000 cases were intubated with alternative methods to direct laryngoscopy in a 20 center study2
Levitan R. Myths and Realities: The “Difficult Airway” and Alternative Airways in the Emergency Setting. Acad EM, 2001; 8:8, 829
Walls RM, et al. 6,294 emergency department intubations: second report of the ongoing National Emergency Airway Registry (NEAR) II study. Ann Emerg Med. 2000; 36(4, part 2)

3. EM physicians are airway experts and direct laryngoscopy is very reliable…
But what if things aren’t as straight forward??

4. Direct Laryngoscopy
There are multiple variations and adjuncts to help with direct laryngoscopy
These include the Macintosh blade, the Miller blade, the McCoy blade, and the bougie
These have been around longer and most people are familiar with their use
This talk will focus on alternatives to direct laryngoscopy further down the difficult airway algorithms

5. Objectives
Review the anticipated and unanticipated difficult airway algorithms
Present alternatives to direct laryngoscopy
Review manual in-line stabilization
Review case scenarios and present options for managing airway difficulties
Glidescope Demo (Maybe)

6. July 1st 2008, Level 1 Trauma: EMS unable to intubate!

7. July 30th, 2008 - EMS Patch: Can’t intubate and can’t ventilate!

8. The Anticipated Difficult Airway
Difficult Bag-Mask (MOANS)
Mask Seal (beard, nose, etc)
Obese/Obstruction
Age >55
No teeth
Stiff (asthma, COPD)
Difficult Intubation (LEMON)
Look externally-gestalt
Evaluate 3-3-2
Mallampati
Obstruction- stridor, drooling
Neck Mobility
Double Set-Up
3-3-2 Thyromental, Mouth Opening, Larynx-Tongue
Emergency Airway Algorithm-developed because the American College of Surgeons ATLS algorithm doesn’t take into account medical indications for intubation. It also doesn’t cover neuromuscular blockade.
Walls, R. Manual of Emergency Airway Management. 2nd Ed, 2004

9. The Unanticipated or Failed Airway
Walls, R. Manual of Emergency Airway Management. 2nd Ed, 2004

10. Glidescope

11. Video Laryngoscopy (Glidescope)
Similar shape to laryngoscope blade
Exagerated curve designed to wrap around tongue, not displace into submental space
Does not require anterior lift/pressure to bring glottis into view
Accompanying rigid stylet increases ETT manouverability
Camera protected in housing with anti-fog heating
Overall glidescope success rates: 99.96%3
3 Cooper RM, et al. Early clinical experience with a new videolaryngoscope in 728 patients. Can J Anesth. 2005; 52:

12. Summarizing the Data
“Can we recommend any of these devices? Most data contains flaws, most data comes from normal patients who are rarely difficult to intubate and much of the data is heterogeneous. Accepting these limitations, the devices with robust data that performed best were the Bonfils and Ctrach in normal patients, and the Bonfils, CTrach and Glidescope in ‘difficult’ patients. Before drawing conclusions on device performance from the ‘difficult’ patient groups it is important to note the small numbers of patients studied, for each device. There is very limited and inadequate comparative data between devices and compared to the standard Macintosh laryngoscope.”

13. Glidescope vs DL with neck imobility
Ankylosing Spondylitis: 60% had C+L grade 3 or 4 airways, improved to 1 or 2 in 85%4
Another study of AS patients showed 93% of patients had C+L grade improved by 1 or more5
Manual In-Line Stabilization (MILS): Glidescope: 50% Grade 1, 50% grade 2
DL: 65% Grade 2, 35% Grade 3 (without BURP)6
Study 6: only 20 patients, all but 1 grade 3 views improved to 2 with BURP. Healthy patients, no neck pathalogy.
4 Lai HY, et al. The use of the Glidescope for tracheal intubation in patients with ankylosing spondylitis. B J Anesth. 2006; 97:3, 419.
5 Argo F, et al. Tracheal intubation using a Macintosh laryngoscope or a Glidescope in 15 patients with cervical spine immobilization. B J Anesth. 2001; 93: 705.
6 Huang WT, et al. Clinical comparisons between GlideScope video laryngoscope and Trachlight in simulated cervical spine instability. J Clin Anesth. 2007; 19(2):110-4

14. Cormack + Lehane Grades

15. Other difficult airways
Anesthesia staff/residents performing elective nasotracheal intubation: C+L G1- 94% vs 66%, with time of 23.3sec vs 43 sec and less sore throat7
2 studies on obese patients w /BMI>408,9
Device used was Airtrach videolaryngoscope
318 pts: Time: 29s vs 109s, Grades: 100/6/0/0 vs 54/36/16/0. More desats + blind attempts
108 pts: Time: 24 sec vs 56 sec, 1 vs 9 desats below 92%
Success rates for obese patients: 100 vs 99% study 1, 100% vs 89% study 2
7 Jones PM, et al. A comparison of Glidescope videolaryngoscopy to direct laryngoscopy for nasotracheal intubation. Anesth and Analg. 2008; 107:1, 144.
8 Dhonneur G, et al. Video-assisted versus conventional tracheal intubation in morbidly obese patients. Obes Surg. 2008; Sept.
9 Ndoko SK, et al. Tracheal intubation of morbidly obese patients: a randomized trial comparing performance of Macintosh and Airtraq laryngoscopes. B J Anaes. 2008; 100:2, 263.

16. C-Spine Movement
Healthy pt’s, C-spine motion from occiput to C5 measured with fluoro during intubation
No difference b/w GS and DL28
Anther compared GS, Trachlight and DL10
Movement measured with fluoro at 4 sites:occiput/C1, C1/C2, C2-C5, C5-T1
TL (%decr): 49, 72, 64, 41 (Mean 57%)
GS (%decr): 0, 0, 50%, 0
Possible C2-C5??
28 Robitaille A, et al. Cervical spine motion during tracheal intubation with manual in-line stabilization: direct laryngoscopy versus Glidescope videolaryngoscopy. Anesth Analg. 2008; 106:3, 935
Turkstra TP, et al. Cervical spine motion: a fluoroscopic comparison during tracheal intubation with lighted stylet, Glidescope, and Macintosh laryngoscope. Anesth Analg. 2005; 101,

17. Hemodynamics
Glidescope shown to have no advantage or disadvantage hemodynamically compared to direct laryngoscopy
No significant difference in MAP or HR6
6 Huang WT, et al. Clinical comparisons between GlideScope video laryngoscope and Trachlight in simulated cervical spine instability. J Clin Anesth. 2007; 19(2):110-4

18. Glidescope Problems CJA study, 14 pt’s failed despite Gr1 view3
Unable to maneuver ETT into glottis
Thought to be overcome with 90 degree stylet
Poor visualization with blood/secretions (better than flex scope)
Needs to be sterilized b/w uses or require disposable handles ($$$)
Shown to take longer with increased apnea and no difference in success for easy airways12
CJA Study: 702/ of 26 failed were Grade 1.
Cooper RM, et al. Early clinical experience with a new videolaryngoscope in 728 patients. Can J Anesth. 2005; 52
12 Lim TJ, et al. Evaluation of ease of intubation with the Glidescope or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy. Anaesth. 2005; 60, 180. :

19. Glidescope Conclusions
Will improve glottic view and success with most difficult airways
Useful teaching tool and easier for novices
Can be used as an adjunct with other devices: Trachlight, Bronchoscope
Doesn’t appear to convey any C-spine or hemodynamic advantages
Still not first-line for anticipated easy airways

20. Other Fiberoptic Laryngoscopes
C-Trach
Airtrach
McGrath
Bonfils

21. Trachlight Flexible stylet with bright LED @ end
Blind intubation technique
Re-usable

22. Trachlight vs DL Similar success rates with C+L Grades 1+213
Improved success, faster and decreased trauma with Grades 3+413
Decreased C-Spine motion compared to DL and Glidescope10
One study has shown smaller rise in HR and MAP compared to DL6
4 other studies show no difference in hemodynamics13-16
13 Davis L, et al. Lighted stylet tracheal intubation: A review. Anesth Analg. 2000; 90, 745.
14 Knight RG, et al. Arterial blood pressure and heart rate response to lighted stylet or direct laryngoscopy for endotracheal intubation. Anesthesiology. 1988; 69: 269.
15 Friedman PG, et al. A comparison of light wand and suspension laryngoscopic intubation techniques in outpatients. Anesth Analg. 1997; 85: 578.
16 Hirabayashi Y, et al. Effects of lightwand (Trachlight) compared with direct laryngoscopy on circulatory responses to tracheal intubation. B J Anaes. 1998; 81: 253.

23. Potential Advantages
Micro/retrognathia: Treacher-Collins, Pierre Robin, etc
Neck immobility: C-spine
Blood/Secretions (alone/with DL/Glidescope)
Traditional markers of difficult intubation don’t appear to affect success with Trachlight
Lack of mandibular protrusion, Mallampati, C+L grade, short hyomental distance 13,17
Davis L, et al. Lighted stylet tracheal intubation: A review. Anesth Analg. 2000; 90, 745.
17 Agro F, et al. Lightwand intubation using the Trachlight: a brief review of current knowledge. Can J Anesth. 2001; February: 592.

24. Disadvantages
Those with <6 attempts with both Trachlight and DL showed 67% success rate and averaged 22 sec longer with Trachlight compared with DL (94% success)18
Suggest benefits only to those with practice and regular use
Limited with grossly obese habitus and brightly lit rooms
Contraindicated with oropharyngeal tumours, infections, trauma, or presence of FB17
17 Agro F, et al. Lightwand intubation using the Trachlight: a brief review of current knowledge. Can J Anesth. 2001; February: 592.
18 Soh CR, et al. Tracheal intubation by novice staff: the direct vision laryngoscope or the lighted stylet (Trachlight)? Emerg Med J. 2002; 19: 292.

25. Intubating LMA’s

26. Pro-Seal LMA Shown to have better seal than classic LMA11
Allows passage of OG tube to allow stomach decompression
Larger size makes it more difficult to place than classic LMA11
99% success with 2114 pt’s when a bougie is placed through OG opening and into esophagus to guide proper placement20
Excellent when “all else fails”
Brimacombe J, et al. A multicenter study comparing the Proseal and Classic laryngeal mask airway in anesthetized, non-paralyzed patients. Anesthesiology. 2002;96: 289.
20 Goldmann K, et al. Use of Proseal laryngeal mask airway in 2114 adult patients: a prospective study. Amb Anesthesiology. 2008; 107:6, 1856.

27. Intubating LMA’s (Classic + Fasttrach)
Rescue device for failed airway
Useful adjunct for fiberoptic intubation
Definitive airway can be placed blind or with fiberoptic guidance
Multiple options to place ETT: blind, fiberoptic assist, fiberoptic placement of bougie or tube exchanger, Trachlight assist26
Can be done with patient awake21,22
21 Muraika L, et al. Fiberoptic tracheal intubatin through a laryngeal mask airway in a child with Treacher-Collins syndrome. Anesth Analg. 2003;97: 1298.
22 Asai T, et al. Awake tracheal intubation through the laryngeal mask in neonates with upper airway obstruction. Ped Anesth. 2008; 18: 77.
26 Barnett R, et al. Augmented fiberoptic intubation. Crit Care Clinics. 2000; 16:3, 453.

28. Classic LMA Common adult sizes: 3, 4, 5
Need to have bars removed in order to pass ETT (newer versions)
#3: 6-0 tube, #4: 6.5 tube, #5: 7-0 tube19
Need to take connectors off. Don’t fit with suction aparatus.
19 (Aids to fiberoptic intubation) Dr. Srinivasan, Kuwait.

29. I-LMA (Fastrach) Accomodates up to size 8-0 ETT19
Metal handle for maneuverability
Comes with flexible, cuffed ETT and stabilizing rod
(Aids to fiberoptic intubation) Dr. Srinivasan, Kuwait.

30. Youtube Video: Awake I-LMA

31. Intubating LMA’s
Success rates of 100% for fiberoptic and lightwand assisted intubations19,23
2 small studies showed blind ETT passage with I-LMA ~95%24,25
For those with predicted short course of intubation: LMA can be left in place
Prolonged LMA placement can lead to tissue ischemia, prevent NG/OG placement as well as access to possible bleeding tissue etc26
LMA will eventually need to be removed for most ER patients
24 Combes X, et al. Intubating laryngeal mask airway in morbidly obese and lean patients. Anesthesiology. 2005; 102: 1106.
25 Frappier J, et al. Airway management using the intubating laryngeal mask airway for the morbidly obese patient. Anesth Analg. 2003; 96: 1510.

32. Intubating LMA’s and Bronchoscope
Fiberoptic ETT placement can be difficult or impossible in certain situations
Retro/micrognathia: posterior tongue and anterior larynx can create angles too steep to maneuver scope26
Blood/secretions: unable to visualize larynx
Fiberoptic takes time to set up. LMA allows ventilation while preparing ETT placement
26 Barnett R, et al. Augmented fiberoptic intubation. Crit Care Clinics. 2000; 16:3, 453.

33. Retro/micrognathia
Pierre Robin
Treacher Collins

34. Intubating LMA’s and Difficult Airways
Case reports: 4 patients with Treacher-Collins and 2 with Pierre Robin
Failed awake fiberoptic intubation
100% successful with first attempt at ETT placement through I-LMA21,22
Obese pt’s (avg BMI 42 vs 23 control)
Blind passage of ETT: 96% obese vs 94%24
Another study of pt’s with average BMI 45
96.3% success rate at blind ETT passage25
Need study numbers and more details. Obese airway thought to provide guide and allow snugger fit.
21 Muraika L, et al. Fiberoptic tracheal intubatin through a laryngeal mask airway in a child with Treacher-Collins syndrome. Anesth Analg. 2003;97: 1298.
Asai T, et al. Awake tracheal intubation through the laryngeal mask in neonates with upper airway obstruction. Ped Anesth. 2008; 18: 77.
24 Combes X, et al. Intubating laryngeal mask airway in morbidly obese and lean patients. Anesthesiology. 2005; 102: 1106.
25 Frappier J, et al. Airway management using the intubating laryngeal mask airway for the morbidly obese patient. Anesth Analg. 2003; 96: 1510.

35. Issues/Problems w/ ILMA’s
Sellick’s increases difficulty of passing ETT23
Only small ETT’s able to pass through classic LMA’s (not ideal for long intubations)
Removing the LMA once ETT placed!!
This is not a simple procedure and there is a high risk of accidental extubation
23 Reardon R, et al. The intubating laryngeal mask airway: suggestions for use in the emergency department. Acad Emerg Med. 2001; 8:8, 833.

36. Removing the LMA
Needs to be planned-out and should be done with help of an assistant
Several options for LMA removal
Fasttrach comes with stabilizing rod that is designed to hold ETT in place while LMA is withdrawn (not ventilating during procedure)
Other reports of coupling 2 ETT’s together to continue ventilation while ETT is withdrawn 21,27
Once distal part of ETT visible, have assistant hold with McGill forceps
Demo ETT’s coupled together and removal of Fastrach
Muraika L, et al. Fiberoptic tracheal intubatin through a laryngeal mask airway in a child with Treacher-Collins syndrome. Anesth Analg. 2003;97: 1298.
27 Weiss M, et al. Continuous ventilation technique for laryngeal mask airway removal after fiberoptic intubation in children. Ped Anesth. 2004;14: 936.

37. Intubating LMA’s-Conclusions
Rescue device for failed airways while retaining the option for definitive airway placement
Facilitating fiberoptic intubation in difficult patients
LMA should be removed for most ER cases and this is a technical and risky process
ET tubes that fit with the Pro-Seal and Classic LMA’s are too small for prolonged intubations

38. Manual In-Line Stabilization (MILS)

40. MILS
Adopted in 1980’s after stabilization during transport improved spinal outcomes29
Since it’s advent there have been 10 cases of 2o injury associated with airway management29
These cases reviewed in Br J Anesthesiology in 2000 and found 1 possibly due to DL and intubation
This case had a neck hematoma, prolonged hypoxia and required an emergent cric.
29 Manoach S, et al. Manual in-line stabilization for acute airway management of suspected cervical spine injury: historical review and current questions. Annals Emerg Med. 2007;50:3, 236.

41. Does MILS work?
2 cadaveric studies of C-spine motion with total of 9 patients29
Data using MILS in live patients comes from 5 case series’ of 275 injured patients.
In this series, 120 patients had unstable but salvageable injuries. No secondary injury observed.
Were these results because of MILS or in spite of??

42. Is MILS a bad thing?
MILS worsens C+L view, increases chance of failed intubation29,30
Jaw thrust has shown to cause more segmental motion than DL29
Jaw thrust is ubiquitous in suspected C-spine injuries and no reports of 2o injury exist29
4 cadaveric studies and 1 on healthy volunteers found no difference or worsening of cervical motion with MILS.29 Why??
30 Santoni BG, et al. Manual in-line stabilization increases pressures applied by the laryngoscope blade during direct laryngoscopy and endotracheal intubation. Anesthesiology. 2009; 110: 24.

43. Each patient underwent standard DL and then laryngoscopy with MILS
Pressure averaged 2x greater with MILS
Previous study done by same group showed pressure transmitted to cranio-cervical motion
66% of patients with MILS had worse C+L views
Only 9 patients. Transducers applied to blade.

44. MILS Conclusions
Annals review states more research needed to come to a firm conclusion
Anesthesiology 2009 editorial by Annals authors, states lack of 2o injury in-spite, not because of MILS31
Stabilization in transport and caution during intubation likely all that’s required to prevent 2o injury
Is MILS worth a potential failed intubation??
31 Manoach S, et al. Laryngoscopy force, visualization, and intubation failure in acute trauma. Anesthesiology ; 110: 6-7.

45. Case 1

46. Awake Intubation OK if you have time OK if no C-spine concerns
Obese pt’s can desat even with sedation for awake intubation
Glidescope can be used to help position bronchoscope tip32
Glidescope can be used to move tongue and visualize landmarks for patients with large tongue, retrognathia33
Glidescope shown to be tolerated and successful for awake intubations34
32 Xue FS, et al. Glidescope-assisted awake fiberoptic intubation: initial experience with 13 patients. Anesthesiology. 2006;61: 1007
33 Vitin AA, et al. A difficult case with Glidescope-assisted fiberoptic intubation. J Clin Anesth. 2007; 564.
34 Doyle DJ. Awake intubation using the Glidescope videolaryngoscope: initial experience in 4 cases. Can J Anesthesia. 2004; 55:5, 520.

47. Case 1: RSI
Easiest and most important maneuver to maximize success????
POSITION!!!

48. Troop Pillow Available in the OR’s of all 3 hospitals.
Or could just use lot’s of blankets!!

49. Case 1: Rescue or Adjunct
Glidescope works well
Intubating LMA shown to be highly successful with obese patients
Allows ventilation while definitive airway placed
Trachlight not a good option in obese patients

50. Case 2

51. Retro/Micrognathia
Direct laryngoscopy difficult because no place to displace tongue
Fiberoptic intubation difficult because of posterior tongue and anterior larynx33
Glidescope doesn’t require displacement of tongue
Options: Glidescope, Glidescope combination with bronchoscope or lighted stylet35****
Intubating LMA as a rescue device or to facilitate fiberoptic intubation
Mention turning light off on stylet until in glottis to confirm.
33 Vitin AA, et al. A difficult case with Glidescope-assisted fiberoptic intubation. J Clin Anesth. 2007; 564.
35 Leissner KB, et al. Intubation with simultaneous use of the Glidescope and the Trachlight. J Anesth. 2008; 22: 328.

52. Case 3: Bleeding

53. Case 3: Suction, suction, suction Yonkers are your friend
Direct Laryngoscopy: push on chest and aim for bubble
Trachlight: excellent light transmission through blood/secretions17,35
Can use in combo with DL, Glidescope35
Intubating LMA with trachlight for rescue
Ask about secretions. Which induction agent can increase secretions.
17 Agro F, et al. Lightwand intubation using the Trachlight: a brief review of current knowledge. Can J Anesth. 2001; February: 592.
35 Leissner KB, et al. Intubation with simultaneous use of the Glidescope and the Trachlight. J Anesth. 2008; 22: 328.

54. Thank You!!

55. References
Levitan R. Myths and Realities: The “Difficult Airway” and Alternative Airways in the Emergency Setting. Acad EM, 2001; 8:8, 829
Walls RM, et al. 6,294 emergency department intubations: second report of the ongoing National Emergency Airway Registry (NEAR) II study. Ann Emerg Med. 2000; 36(4, part 2)
Cooper RM, et al. Early clinical experience with a new videolaryngoscope in 728 patients. Can J Anesth. 2005; 52:
Lai HY, et al. The use of the Glidescope for tracheal intubation in patients with ankylosing spondylitis. B J Anesth. 2006; 97:3, 419.
Argo F, et al. Tracheal intubation using a Macintosh laryngoscope or a Glidescope in 15 patients with cervical spine immobilization. B J Anesth. 2001; 93: 705.
Huang WT, et al. Clinical comparisons between GlideScope video laryngoscope and Trachlight in simulated cervical spine instability. J Clin Anesth. 2007; 19(2):110-4
Jones PM, et al. A comparison of Glidescope videolaryngoscopy to direct laryngoscopy for nasotracheal intubation. Anesth and Analg. 2008; 107:1, 144.
Dhonneur G, et al. Video-assisted versus conventional tracheal intubation in morbidly obese patients. Obes Surg. 2008; Sept.
Ndoko SK, et al. Tracheal intubation of morbidly obese patients: a randomized trial comparing performance of Macintosh and Airtraq laryngoscopes. B J Anaes. 2008; 100:2, 263.
Turkstra TP, et al. Cervical spine motion: a fluoroscopic comparison during tracheal intubation with lighted stylet, Glidescope, and Macintosh laryngoscope. Anesth Analg. 2005; 101,
11 Brimacombe J, et al. A multicenter study comparing the Proseal and Classic laryngeal mask airway in anesthetized, non-paralyzed patients. Anesthesiology. 2002;96: 289.
12 Lim TJ, et al. Evaluation of ease of intubation with the Glidescope or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy. Anaesth. 2005; 60, 180.
13 Davis L, et al. Lighted stylet tracheal intubation: A review. Anesth Analg. 2000; 90, 745.
14 Knight RG, et al. Arterial blood pressure and heart rate response to lighted stylet or direct laryngoscopy for endotracheal intubation. Anesthesiology. 1988; 69: 269.
15 Friedman PG, et al. A comparison of light wand and suspension laryngoscopic intubation techniques in outpatients. Anesth Analg. 1997; 85: 578.
16 Hirabayashi Y, et al. Effects of lightwand (Trachlight) compared with direct laryngoscopy on circulatory responses to tracheal intubation. B J Anaes. 1998; 81: 253.
17 Agro F, et al. Lightwand intubation using the Trachlight: a brief review of current knowledge. Can J Anesth. 2001; February: 592.
18 Soh CR, et al. Tracheal intubation by novice staff: the direct vision laryngoscope or the lighted stylet (Trachlight)? Emerg Med J. 2002; 19: 292.
19 (Aids to fiberoptic intubation) Dr. Srinivasan, Kuwait.
20 Goldmann K, et al. Use of Proseal laryngeal mask airway in 2114 adult patients: a prospective study. Amb Anesthesiology. 2008; 107:6, 1856.

56. References
21 Muraika L, et al. Fiberoptic tracheal intubatin through a laryngeal mask airway in a child with Treacher-Collins syndrome. Anesth Analg. 2003;97: 1298.
22 Asai T, et al. Awake tracheal intubation through the laryngeal mask in neonates with upper airway obstruction. Ped Anesth. 2008; 18: 77.
23 Reardon R, et al. The intubating laryngeal mask airway: suggestions for use in the emergency department. Acad Emerg Med. 2001; 8:8, 833.
24 Combes X, et al. Intubating laryngeal mask airway in morbidly obese and lean patients. Anesthesiology. 2005; 102: 1106.
25 Frappier J, et al. Airway management using the intubating laryngeal mask airway for the morbidly obese patient. Anesth Analg. 2003; 96: 1510.
26 Barnett R, et al. Augmented fiberoptic intubation. Crit Care Clinics. 2000; 16:3, 453.
27 Weiss M, et al. Continuous ventilation technique for laryngeal mask airway removal after fiberoptic intubation in children. Ped Anesth. 2004;14: 936.
28 Robitaille A, et al. Cervical spine motion during tracheal intubation with manual in-line stabilization: direct laryngoscopy versus Glidescope videolaryngoscopy. Anesth Analg. 2008; 106:3, 935.
29 Manoach S, et al. Manual in-line stabilization for acute airway management of suspected cervical spine injury: historical review and current questions. Annals Emerg Med. 2007;50:3, 236.
30 Santoni BG, et al. Manual in-line stabilization increases pressures applied by the laryngoscope blade during direct laryngoscopy and endotracheal intubation. Anesthesiology. 2009; 110: 24.
31 Manoach S, et al. Laryngoscopy force, visualization, and intubation failure in acute trauma. Anesthesiology ; 110: 6-7.
32 Xue FS, et al. Glidescope-assisted awake fiberoptic intubation: initial experience with 13 patients. Anesthesiology. 2006;61: 1007
33 Vitin AA, et al. A difficult case with Glidescope-assisted fiberoptic intubation. J Clin Anesth. 2007; 564.
34 Doyle DJ. Awake intubation using the Glidescope videolaryngoscope: initial experience in 4 cases. Can J Anesthesia. 2004; 55:5, 520.
35 Leissner KB, et al. Intubation with simultaneous use of the Glidescope and the Trachlight. J Anesth. 2008; 22: 328.