The Difficult Airway© 2009 Ron M. Walls, MD

Five New Devices for the Difficult Airway

Ron M. Walls, MDBrigham and Women’s Hospital

Harvard Medical School

The Difficult Airway© 2009 Ron M. Walls, MD

A Haiku

Can’t intubate, can’t ventilate…Panic. Flail. Brain Cells

die in bunches.

New Devices for the Difficult Airway

The Difficult Airway© 2009 Ron M. Walls, MD

Outline

• Magnitude of the problem • Where do new devices fit in?• New devices

New Devices for the Difficult Airway

The Difficult Airway© 2009 Ron M. Walls, MD

Difficult Laryngoscopy: Cormack-Lehane Score

The Difficult Airway© 2009 Ron M. Walls, MD

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

New Devices for the Difficult Airway

The Difficult Airway© 2009 Ron M. Walls, MD

How common is difficultbag mask ventilation?

• In the OR (patients are pre-selected)– Difficult BMV in 1.5 - 5%– 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 92 1229-1236. Kheterpal S et al. Anesthesiology 2006 Nov; 105:885-91.

The Difficult Airway© 2009 Ron M. Walls, MD

Outline

• Magnitude of the problem • Where do new devices fit in?• New devices

New Devices for the Difficult Airway

The Difficult Airway© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

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?

Where do new devices fit in?

The Difficult Airway© 2009 Ron M. Walls, MD

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!

Where do new devices fit in?

The Difficult Airway© 2009 Ron M. Walls, MD

• These are “every intubation” devices

• There is a learning curve

• The question is not whether, but which, and when?

Where do new devices fit in?

The Difficult Airway© 2009 Ron M. Walls, MD

Outline

• Magnitude of the problem • Where do new devices fit in?• New devices

New Devices for the Difficult Airway

The Difficult Airway© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

Glidescope

• Video laryngoscope• Minimal mouth opening required• Very high intubation success rate• Allows “teacher” to share view with “student”• Portable, durable

New Devices for the Difficult Airway

The Difficult Airway© 2009 Ron M. Walls, MD

GlidescopeNew Devices for the Difficult Airway

The Difficult Airway© 2009 Ron M. Walls, MD

How good is

the Glidescope?

The Difficult Airway© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

McGrath Videolaryngoscope

• Videoscope with built in screen• Blade design similar to GS• Plastic sheath for blade• Blade adjustable

The Difficult Airway© 2009 Ron M. Walls, MD

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 2008 100(1):116-119Shippey B: Can J Anaesth 2007; 54:307-313.

The Difficult Airway© 2009 Ron M. Walls, MD

Storz Video Laryngoscope

• Video/FO laryngoscope• Based on standard blades• Interchangeable video camera system• Pediatric and adult blades• High quality optics

The Difficult Airway© 2009 Ron M. Walls, MD

Storz CMAC®(now released)

The Difficult Airway© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

Pentax AWS®(not yet released in the US)

• Videoscope with preload tube channel• Lenticle helps aim• Light, portable

The Difficult Airway© 2009 Ron M. Walls, MD

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 2008 100(4):544-548Suzuki A: Anaesthesia. 63(6):641-647, June 2008. Takenaka I: Anesthesiology 110:1335-40, June 2009.

The Difficult Airway© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

SOS

• Malleable FO• Midline approach• Inexpensive• Video adaptable

The Difficult Airway© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

Air RIFL®

• New dynamically adjustable FO stylet• Little/no research data• No real clinical experience (yet)• Cool entrepreneurial website, though

The Difficult Airway© 2009 Ron M. Walls, MD

Bonfils Stylet

• Non-malleable

• Retro-molar approach

• Popular in N Europe

• Self contained

• High quality optics

• Higher price than SOS

The Difficult Airway© 2009 Ron M. Walls, MD

AirTraq®New Devices for the Difficult Airway

• “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© 2009 Ron M. Walls, MD

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© 2009 Ron M. Walls, MD

The Difficult Airway© 2009 Ron M. Walls, MD

And the Venerable Laryngoscope?

The Difficult Airway© 2009 Ron M. Walls, MD

Prediction

By 2010, a minority ofED intubations will be done

using a conventional laryngoscope and blade.

www.theairwaysite.com

New Devices for the Difficult Airway

The Difficult Airway© 2009 Ron M. Walls, MD

Another Haiku

Can’t intubate. Can’t ventilate. Knew in advance.

Plan rescues the life.

www.theairwaysite.com

New Devices for the Difficult Airway

The Difficult Airway© 2009 Ron M. Walls, MD

The Difficult Airway

FIN