Salvaging the Difficult Airway - A Practical Approach

Richard M. Levitan, MD (levitanr@mail.med.upenn.edu)

Department of Emergency Medicine

Hospital of the University of Pennsylvania, Philadelphia PA

1. Historical Perspective

1895: Kirstein first direct laryngoscopy

1910: Jackson vector forces, techniques (straight blades)

1930’s: Miller & Macintosh spatula blades (curved or curved tip)

1970’s: Flexible fiberoptics

1980’s: Rigid fiberoptics (Bullard)

1990’s: RSI, “Difficult Airway”, search for the holy grail

2000’s: DL revisited, Rescue ventilation

2. Intubation Devices

Standard blades (Macintosh, Miller)

Non-standard blades (Phillips, Guedel, Wis, Mac IV, reduced flange)

Articulating laryngoscope (Corazelli-London-McCoy)

Lighted stylets (Trachlight, Vital light, etc.)

Gum elastic bougie, plastic reproduction

Retrograde kit

Blind orotracheal devices: Augustine Guide, Parker Intubating Guide

Bullard laryngoscope

Wu, Upsher rigid fiberoptic laryngoscopes

Flexible fiberoptic scopes: length 26-60 cm, varying diameters, features

Fiberoptic stylets (Shikani, Visualized endotracheal tube, "Shuttle")

Intubating LMA

Surgical devices

3. Ventilation devices

Face mask

Cuffed oral pharyngeal airway--COPA

Esophageal obturator airway

Esophageal-Tracheal Combitube

Laryngeal Mask Airway (Unique, Classic, Fastrach)

Trans-tracheal jet ventilation

4. What exactly is the “difficult airway”

Multiple attempts

Poor laryngeal view--POGO score (Percentage of Glottic Opening)

Cormack and Lehane grading system

The anatomically unfavorable

The one you can’t get

Intubation Difficult Scale

5. Anatomy unfavorable to direct laryngoscopy: Four D's

Distortion (trauma, infection, neoplasm, edema, hemorrhage, vomitus)

Disproportion (tongue/pharynx, thyromental-displacement space)

Dysmobility (atlanto-occipital joint, neck mobility, TMJ)

Dentition (prominent incisors)

6. Anatomy unfavorable for ventilation

Beard

Obesity

Edentulous

Large tongue

Eldelry

7. The Elective OR Setting

Controlled, pre-operative assessment

NPO, pre-medicated: low risk aspiration

VSS and not hypoxic

Cooperative

Luxury of time

Deep sedation w/o paralysis or apnea

Wake up patient and cancel case

8. Devices for Difficult Airways in Emergency Departments

No standard training or requirements

Non-controlled setting

Limited pre-procedural evaluation

Hypoxia, hypotension, agitation, dynamic medical conditions

Numerous logistical & implementation issues

9. Logistical Issues, ED’s, & Difficult Airway Devices

Educational: skill acquisition & retention, complexity, frequency of use

Economic: purchase, maintenance, loss, repair and replacement

Implementation: speed, success and complication rates,

use with blood, vomitus, secretions, C-spine immobilization

10. Incidence of Difficult Airways

1-18% in OR depending upon criteria

Failed laryngoscopy rate in OR: 5-35 in 10,000

Cannot intubate, cannot ventilate rate: 2 in 10,000

Difficult mask ventilation 5%, inability to mask ventilate 1/1500

In ED’s, DL successful 99-99+% overall & >90% of “difficult airways”

11. Incidence of Difficult Airways: ED case series…

Nasal 0.2 - 1.3%

RSI used > 80% cases

In ED’s, 3 or more attempts: 3-5.3%

Failed laryngoscopy < 1.0%

Cric rates 0.5% - 1.2%

Sackles JC. Ann Emerg Med, 1998;31:325-32

Calderon Y. Acad Emerg Med, 1995;2:411-2

Riggs RW. Acad Emerg Med, 1996;3:528

Vissers RJ. Acad Emerg Med, 1998;5:481

12. The bottom line: HUP as an example

500 airways per year (half trauma)

25 attendings, 36 residents

Failed laryngoscopy rate: <1%, approximately 1 surgical per year

1 failed airway in 5 years per attending

Most residents will neither see nor do a surgical airway (cadaver only)

13. The real problem with “the difficult airway” for ED’s

Doesn’t occur often enough

Devices not integrated the ED airway

Historic approach or rigid algorithm

(i.e. repeat laryngoscopy until cricothyrotomy) not appropriate

? reason for difficult intubation

? need for prolonged respiratory support

? skills/experience of provider

? effective rescue ventilation options

14. A Practical Approach

-Master DL--Progressive visualization, positioning, ELM, head elevated laryngoscopy position

-Embrace simple devices that fit with what you already do--

gum elastic bougie, rescue straight blade, nasal

-Rescue ventilation for rare cannot intubate/ventilate--LMA, Combitube

-Surgical: cricothyrotomy (4 step), retrograde kit

15. The Emergency Airway 2001: An Overview… [See end of handout]

16. Nasal Intubation

Endotrol tube and BAAM whistle

Prep: 2 sprays Afrin & 2 cc’s 4% lidocaine solution,

then trumpet with lidocaine jelly placed and removed

Insert straight back, not upwards; position patient correctly (sniffing)

Use trigger tube or cuff inflation to bring tip forward

Beck Airflow Airway Monitor

Directional control tube for BNTI

17. Fiberoptic Nasal Intubation

Olympus models: T3 > LF-2 >>>> P4

T3: 36.5 cm L, 5.0 mm OD, 2.2 mm SC

LF-2: 60 cm L, 4.0 mm OD,1.5 mm SC

P-4: 30 cm L, 3.6 mm OD, no SC

18. Educational Issues FO

Too few airways require FO intubation

Short scope skills = FO intubation skill

Burke LP. Anaesthesia. 51(1):81-3, 1996.

ENT clinic practice = OR intubation

Magic number ? 10

Smith JE. Anaesth, 52:101-6, 1997.

Delaney KA. Ann E Med, 17: 919-27, 1988.

T3 scope -- single scope for both uses

19. Logistical Issues FO

Blood and secretions are the enemy of the bronchoscopist

72% success rate in ED series

Afilalo M. J Emerg Med. 11: 387-91,1993.

Repetitive laryngoscopy -- blood,edema

Cost ($6,000 P-4 to $10,000 T-3)

Repair

Cleaning

20. Cleaning & Sterilization

Fiberoptic Nasal Intubation
Technique

Working channel for suction, not O2 (barotrauma risk)

Prep, place tube into pharynx first

Sitting up if possible, or use jaw thrust or tongue traction

Place scope past cords before sliding tube off

21. Fiberoptic Nasal Intubation

Technique: Tube rotation

Hughes S. Anaesth, 51:1026-8, 1996.

90 patients, randomly assigned to 1/3 groups

Group 1: no rotation, Group 2: 90 degrees CCW, Group 3: 180 degrees CCW & then back to 90

1st pass success: 63% - 93% - 100%

22. Fiberoptic vs. blind technique, (using cuff inflation)

Van Elstraete. Anesth Analg. 87:400-2, 1998.

N=20, each twice, once with each, max 3 attempts blind, max 3 minutes for each FO attempt

Inflation 19/20 (95%), 1st try 14/20 (70%)

Fiberoptic success rate 19/20 (95%)

20.8 +/- 23 vs. 60.1 +/- 56 seconds (P < 0.01).

23. Awake DL

Topicalization / sedation

Awake look to determine likelihood of ability to intubate

Best in deeply obtunded (COPD wth hypercarbia, overdose, EtOH)

Risk of regurgitation, trauma

24. Limitations of evaluating the Four D’s in ED setting

Mallampati (tongue /pharynx ratio)--upright, no phonation, maximal effort

Often unable to check neck mobility

Prediction of difficulty even in OR setting works poorly

25. Advantages of RSI

Unparalleled success, speed, simplicity

Improved success rates vs. brutane

Lower complications vs. brutane

Succinyl choline increases LES tone

World experts with their respective alternative devices do not match the speed and overall success of DL reported by ED studies

26. RSI--Timing principle

Time to critical desaturation depends upon illness, body habitus, anemia Time to recovery from sux - 9 minutes

Preoxygenation!

Give paralytic agent before induction agent --limit apneic period

Most important with non-depolarizers, but also helps with sux

27. Ventilation

Position properly

Have oral/nasal airways, ?COPA

Mask ventilation-- Lift chin, hyoid, elevate hypopharyngeal structures

28. Laryngoscopy and Ventilation

Maximal number of attempts? 4?

Sometimes evident immediately

Repeat forceful laryngoscopy > bleeding, edema > inability to ventilate

Do something different!

Do not begin again if patient hypoxic

29. Laryngoscopy

Positioning--obesity--massive support

C spine--remove front of collar

Progresive visualization!

ELM, not cricoid, not BURP

Head Elevated Laryngoscopy Position (HELP) bring head up more

Bougie or lighted stylet for directing under epiglottis

30. Laryngeal manipulation

Moves larynx into view

Correctly sits tip of curved blade into vallecula

Allows effective indirect control of epiglottis

31. Laryngeal manipulation - historical background / efficacy

“Autoscopy by counterpressor” [Brunnings, 1912]

“laryngeal lift” [Krantz MA. J Clin Anesth 1993; 5:297-301]

“OELM” [Benumof JL. J Clin Anesth 1996; 8:136-140]

“BURP” [Knill RL. CJA 1993; 40: 798-9]

"BURP" [Takahata O. J Clin Anesth 1996; 8:136-140]

Videographic analysis [Levitan RM Anesth Analg, 2001; 92:267-70]

32. Rescue Straight Blade Technique

Paraglossal placement

Identify epiglottis first; tilt and lift

Miller lumen does not accept tracheal tube; must go around

Wisconsin, Phillips, Guedel, other historic straight designs

33. Rescue Straight Blade--Henderson design

Lumen large enough for #8.0 tube

Visible distal tip

Broad tip shape, i.e. not pointed

Fiberoptic light

Light bundle recessed--does not project into lumen

Karl Storz, $270

34. Head Elevated Laryngoscopy Position

Response to poor visualization should be additional head elevation

35. Gum Elastic Bougie

"Eschmann Stylet"
SIMS-Portex ($75 each)

Plastic copy (Greenfield Medical; $105/$10)

36. Lighted Stylet

Range from $30 to $925 (Tube-Stat, Trachlight, The Shuttle)

Ability to use as alternative stylet with standard laryngoscopy

Without laryngoscope bend 90 degrees at level of cuff

Rocking motion; trans-illumination, twist tube off CCW direction

41. Rescue Ventilation

Following failed repeat laryngoscopy immediate need for ventilation

LMA > Combitube >>> Cricothyrtotomy

LMA easiest conversion to intubation

Combitube better aspiration protection and higher airway pressures

Cric-TIME, complexity, complications

42. Rescue Intubation following rescue ventilation:

Through LMA, ILMA - blind or with fiberoptic assistance

Around Combitube or COPA

With lighted stylet

Retrograde (Cook kit, rotate tube CCW)

43. Other rescue intubation techniques: Rigid fiberoptic

Bullard, fiberoptic stylets

44. Surgical approaches

Cric--4 step, by palpation, #4 Shiley

Percutaneous cric (Melker): No faster or more successful

Psychologically less intimidating, lack of aspiration protection

45. Conclusions:

Top 10 techniques & devices to take home--all fit well within emergency airway algorithm, simple to use, relatively inexpensive

1. Recognition of posterior structures, interarytenoid notch

2. Operator directed external laryngeal manipulation - your right hand

3. Head elevated laryngoscopy technique

4. Stainless steel Macintosh blade with fiberoptic light

5. Paraglossal straight blade technique with progressive visualization

-Rescue blade (Henderson > Phillips > Wisconsin > Miller)

6. Endotrol tube with BAAM whistle for nasal intubation

7. Gum elastic bougie

8. Laryngeal mask airway (disposable version, size #3,4,5)

9. Lighted stylet

10. Retrograde intubation kit

QUESTIONS?
Emergency airway 2001: An overview

1.

Nasal intubation

Surgical airway

Oxygenation. 1 Mask ventilate as needed. . .

2. Is the oral route obviously 2 impossible?

3.

Flexible fiberoptic

Tracheotomy

Is there obvious 3 laryngeal pathology?

4. The Four D’s 4 of difficult intubation:

Cardiac arrest / pre-arrest

A. Direct laryngoscopy

B. Combitube / Laryngeal mask

C. Cricothyrotomy

Awake laryngoscopy

Nasal intubation

Alternative device

Cricothyrotomy

Distortion 5

Disproportion 6

Dysmobility 7

Dentition 8

RAPID SEQUENCE INTUBATION with the TIMING PRINCIPLE

Alternative

device:

-Lighted stylet*

-ILMA

-Rigid fiberoptic

Laryngoscopy technique

1. Positioning

2. External laryngeal manipulation

3. HELP: Head elevated laryngoscopy position

4. Lighted stylet*

5. Bougie*

6. Paraglossal straight

7. Phillips blade*

8. Alternative blades

(McCoy, Henderson)

Mask ventilation

-Oral airway

-Chin lift

-Jaw thrust

-Extra hands

-C.O.P.A.*

*Note: asterisk denotes inclusion in low cost difficult airway kit.

Rescue Intubation

A. LMA* / ILMA assisted

B. Blind (lighted stylet,* retrograde*)

C. Rigid fiberoptic

1. Cricothyrotomy

2. Flexible fiberoptic

The Low Cost Difficult Airway Kit

Instrument Supplier/Contact Cost Total

1. Your right hand Self 0 0

2. BAAM whistle Great Plains Ballistics[225-677-8553] $5 5.

3. Endotrol tube (7.0) Mallinkrodt [mallinckrodt.com] $12 12.

4. Lighted stylet Xomed, Tube-stat [xomed.com] $30. 30.

Aaron Medical [aaronmed.com]

5. Retrograde Kit Cook Critical Care

[cookgroup.com/cook_critical_care/index.html] $42 42.

6. Bougie SIMS/Portex [http://www.portexusa.com/] $70 70.

[Flex-Guide Introducer, Greenfield Medical 508-393-7907, $105. for 10]

7. Combitube (SA, A) Sheridan [armstrongmedical.com] $45 each 90.

8. Phillips blade (FO) Anesthesia Medical Specialties $68 68.

[laryngoscopes.com] [mercurymedical.com/]

8. LMA Unique (#3,4,5) LMA North America/Gensia $36 each 108.

[800-788-7999]

TOTAL: $425

The Expensive Difficult Airway Kit

Instrument Supplier/Contact Cost Total

9. Henderson blade Karl Storz [karlstorz.com] $270 270.

10. Trachlight Laerdal (1 handle/10 stylets) $398 398.

[laerdal.com/home.asp] (handle, 20 re-usable $499)

11. CLM-McCoy blade Mercury Medical/Heine $495 495.

[mercurymedical.com/] [www.heineopto.com]

12. Fiberlightview "Shuttle" Anesthesia Medical Specialties $950 950.

[laryngoscopes.com]

12. Intubating LMA (#3,4,5) LMA Co./Gensia $1420 1420.

800-788-7999

TOTAL: $3,533.

The Really Expensive Difficult Airway Kit

Instrument Supplier/Contact Cost Total

13. Bullard Laryngoscope Circon ACMI [circoncorp.com] $3,800 $3,800.

14. LF-2 Fiberscope Olympus [olympusamerica.com] $8,000 $8,000.

15. Wu-Scope Achi [achi.com] $18,155 $18,155.

TOTAL: $ 28,955.

NOTE: Unofficial prices found in catalogues, web sites, or verbal quotes as of 6/00. Contact suppliers.

Notes:

[1] Oxygenation with non-rebreather 15 liters per minute.

2 Severe angioedema, wired jaw, severe Ludwig’s angina, trauma, etc.

3 Thyroid fracture, impaled foreign body in upper neck.

4 From S. Rao Mallampati. Recognition of the difficult airway. In: Benumof JL ed, Airway management: Principles and practice, p 130. Mosby-Yearbook, St. Louis, 1996.

5 Trauma, edema, infection, neoplasm.

6 Large tongue relative to mouth size (Mallampati), recessed chin or short thyro-mental distance (small displacement space), or thick, short neck.

7 Atlanto-occipital extension (head able to be tilted backwards), neck flexion (head able to be elevated), temporo-mandibular joint mobility (mouth opening).

8 Large prominent upper dentition. Laryngoscopy is easiest with no upper dentition; ability to prognath (project lower teeth more forward than upper teeth, Jay Leno look) suggests easy distraction of jaw and large displacement space.

Cardiac arrest

Time to oxygenation is critical. Direct laryngoscopy preferred technique due to speed, familiarity, success rates. Very few patients in cardiac arrest cannot be intubated with a laryngoscope. Though cricothyrotomy provides definitive airway it takes longer than the LMA or Combitube, from start to time to ventilation. Time to ventilation amongst inexperienced clinicians > 100 seconds, regardless of open vs. percutaneous method [rapid 4 step technique not studied]: Eisenburger P. Laczika K. List M. Wilfing A. Losert H. et al. Comparison of conventional surgical versus Seldinger technique emergency cricothyrotomy performed by inexperienced clinicians. Anesthesiology. 92(3):687-90, 2000.

Utility of Combitube in cardiac arrest: Tanigawa K. Shigematsu A. Choice of airway devices for 12,020 cases of nontraumatic cardiac arrest in Japan. Prehospital Emergency Care. 2(2):96-100, 1998. Rumball CJ. MacDonald D. The PTL, Combitube, laryngeal mask, and oral airway: a randomized prehospital comparative study of ventilatory device effectiveness and cost-effectiveness in 470 cases of cardiorespiratory arrest . Prehospital Emergency Care. 1(1):1-10, 1997. Atherton GL, Johnson JC. Ability of paramedics to use the esophageal-tracheal combitube in prehospital cardiac arrest. Ann Emerg Med 1993;22:1263-7. Frass M. Frenzer R. Zdrahal F. Hoflehner G. Porges P. Lackner F. The esophageal tracheal combitube: preliminary results with a new airway for CPR. Annals of Emergency Medicine. 16(7):768-72, 1987.

Though there has been reluctance to use the LMA for cardiac arrest in the US, several studies have shown it to be effective and better than the facemask. Concerns over regurgitation may be overstated assuming proper placement and its use as an initial ventilation aid: Stone BJ, Leach AB, Alexander CA, et al: The use of the laryngeal mask airway by nurses during cardiopulmonary resuscitation--Results of a multicentre trial. Anaesthesia 49:3, 1994. Rumball CJ. MacDonald D. The PTL, Combitube, laryngeal mask, and oral airway: a randomized prehospital comparative study of ventilatory device effectiveness and cost-effectiveness in 470 cases of cardiorespiratory arrest . Prehospital Emergency Care. 1(1):1-10, 1997. Kokkinis K. The use of the laryngeal mask in CPR. Resuscitation. 1994; 27: 9-12. Verghese C, Prior-Willeard PFS, Baskett PJF. Immediate management of the airway during cardiopulmonary resuscitation in a hospital without a resident anesthesiologist. Eur J Emerg Med, 1994; 1: 123-125. . Keller C. Brimacombe J. Radler C. Puhringer F. Do laryngeal mask airway devices attenuate liquid flow between the esophagus and pharynx? A randomized, controlled cadaver study. Anesthesia & Analgesia. 88(4):904-7, 1999. Brimacombe JR, Berry A. The incidence of aspiration associated with the laryngeal mask airway: a meta-analysis of published literature. J Clin Anesth. 1995;7:297-305. Verghese C. Brimacombe JR. Survey of laryngeal mask airway usage in 11,910 patients: safety and efficacy for conventional and nonconventional usage . Anesthesia & Analgesia. 82(1):129-33, 1996.

Nasal intubation

Topicalization with Afrin (or Neosynephrine) and 2 cc of 4% lidocaine if time permits; lidocaine jelly applied to nasal trumpet prior to tube passage. Endotrol tubes (trigger tube) and Beck Airflow Airway Monitor recommended: Hooker EA. Hagan S. Coleman R. Heine MF. Greenwood P. Directional-tip endotracheal tubes for blind nasotracheal intubation. Academic Emergency Medicine. 3(6):586-9, 1996 . If Endotrol and BAAM not available, tracheal tube cuff can be inflated as advanced to help direct it to proper location (anterior and midline): Gorbach MS: Inflation of endotracheal tube cuff as an aid to blind nasal endotracheal intubation. Anesthesia Analg 1987; 66:913-22. Cuff inflation as effective as fiberoptic guided intubation: Van Elstraete AC. Mamie JC. Mehdaoui H. Nasotracheal intubation in patients with immobilized cervical spine: a comparison of tracheal tube cuff inflation and fiberoptic bronchoscopy. Anesthesia & Analgesia. 87(2):400-2, 1998.

Rapid Sequence Intubation: Timing Principle and Critical Desaturation

The timing principle involves administration of paralytic in advance of induction agent, so that onset of drugs is close together or simultaneous. This minimizes the apneic period before the patient is fully relaxed: Culling RC, Middaugh RE, Menk EJ. Rapid tracheal intubation with vecuronium: the timing principle. J Clin Anesth 1989;1:422-5. In some ED situations, even the one minute delayed effect by succinyl choline will result in desaturation. Critical desaturation with succinyl choline will occur before spontaneous breathing returns, dependent upon physiologic parameters and clinical situation: Benumof JL. Dagg R. Benumof R. Critical hemoglobin desaturation will occur before return to an unparalyzed state following 1 mg/kg intravenous succinyl choline. Anesthesiology, 1997; 87(4):979-82.

Laryngoscopy

Speed, simplicity and success rates of direct laryngoscopy make it the mainstay of emergency airway management. Multiple studies in ED, EMS setting have shown success rates @99% when pharmacologic adjuncts are used. Multiple logistical considerations with use of difficult airway devices in ED’s: Levitan RM, Kush S, Hollander JE. Devices for difficult airway management in academic emergency departments: Results of a national survey. Ann Emerg Med, 1999; 33:694-698.

The only device potentially comparable by these three parameters is the lighted stylet (Trachlight), but no large studies have repeated the results of expert users: Hung OR, Pytka S, Morris I, et al. Clinical trial of a new lightwand device (Trachlight) to intubate the trachea. Anesthesiology. 83(3):509-14, 1995. Wik L. Naess AC. Steen PA. Intubation with laryngoscope versus transillumination performed by paramedic students on manikins and cadavers. Resuscitation. 33(3):215-8, 1997. Transillumination most difficult in obesity and dark skin pigmentation--of note, the large studies on the Trachlight were done in Nova Scotia.

External laryngeal manipulation (NOT cricoid, NOT BURP) is the easiest and most effective difficult laryngoscopy technique. Originally described by the pioneers of laryngoscopy for use in laryngeal surgery: Brunnings W. Direct laryngoscopy: Autoscopy by counterpressure. In: Direct laryngoscopy, bronchoscopy, and esophagoscopy. Balliere, Tindall, & Cox, London, pp.110-115, 1912. Zeitels SM. Vaughan CW. "External counterpressure" and "internal distention" for optimal laryngoscopic exposure of the anterior glottal commissure. Annals of Otology, Rhinology & Laryngology. 103(9):669-75, 1994. Benumof JL, Cooper SD. Qualitative improvement in laryngoscopic view by optimal external laryngeal manipulation. J Clin Anesth 1996; 8:136-40. External laryngeal manipulation more effective than McCoy articulating laryngoscope blade in patients optimally positioned: Levitan RM, Ochroch AE. A videographic analysis of external laryngeal manipulation versus the McCoy laryngoscope [Abstract]. Society for Airway Management annual meeting, New Orleans, Sept. 26^th, 1999.

Head elevation, not further extension, recognized by early pioneers as critical in difficult cases: Jackson C, Jackson CL. Bronchoscopy, esophagoscopy and gastroscopy; a manual of peroral endoscopy and laryngeal surgery. Philadelphia, London, W.B. Saunders Company, 1934. Page 100. Utility in difficult laryngoscopy: Ng M. Hastings RH. Successful direct laryngoscopy assisted by posture in a patient with ankylosing spondylitis. Anesth Analg. 87(6):1436-7, 1998. Improved exposure of the glottis versus standard positionming : Hochman II. Zeitels SM. Heaton JT. Analysis of the forces and position required for direct laryngoscopic exposure of the anterior vocal folds. Ann Oto Rhino Laryn. 108(8):715-24, 1999.

The percentage of glottic opening score correlates with number of intubation attempts: Levitan RM, Ochroch AE, Hollander JE. [in press].

Lighted stylet (Laerdal “Trachlight,” Vital Signs “Lightwand,” and others) or gum elastic bougie (SIMS Portex, “Eschmann stylet’) can be useful when view is poor or only the epiglottis is seen. Lighted stylet can be used as an independent method of intubation, but is easiest to use as a stylet aid with a laryngoscope: Biehl JW. Bourke DL. Use of the lighted stylet to aid direct laryngoscopy [letter]. Anesthesiology. 1997;86(4):1012.

Utility of the gum elastic bougie: McGill JW, Vogel EC, Rodgerson JD. Use of the gum elastic bougie as an adjunct for orotracheal intubation in the emergency department [Abstract]. Acad Emerg Med, 2000; 7: 526. Dogra S. Falconer R. Latto IP. Successful difficult intubation. Tracheal tube placement over a gum-elastic bougie . Anaesthesia. 1990;45(9):774-6. Gataure PS. Vaughan RS. Latto IP. Simulated difficult intubation. Comparison of the gum elastic bougie and the stylet. Anaesthesia. 1996; 51(10):935-8.

Paraglossal straight blade technique; blade should be placed fully to the right side of the tongue—do not bring towards midline—tube should be passed around lumen (not through lumen) of Miller blade. Henderson, Phillips, Wisconsin or Guedel blades are large enough to pass tube through lumen; Henderson has smallest flange height and probably best for this technique. Henderson JJ. The use of paraglossal straight blade laryngoscopy in difficult tracheal intubation . Anaesthesia. 1997; 52(6):552-60.

Laryngoscope blade design: McIntyre JW. Laryngoscope design and the difficult adult tracheal intubation . Can J Anaesth1989; 36(1):94-8. McCoy articulating blade and Macintosh improved vision: Racz GB. Improved vision modification of the Macintosh larygoscope [letter]. Anaesthesia, 1984; 39: 1249. Gabbott DA. Laryngoscopy using the McCoy laryngoscope after application of a cervical collar. Anaesthesia, 1996; 51:812-4. Laurent SC, deMelo AE, Alexander-Williams JM. The use of the Mcoy laryngoscope in patients with simulated cervical spine injuries. Anaesthesia 1996; 51:74-5. Levitan RM. Ochroch EA. Explaining the variable effect on laryngeal view obtained with the McCoy laryngoscope [letter]. Anaesthesia. 54:599-601, 1999.

Cuffed Oral Pharyngeal Airway (C.O.P.A., Mallinkrodt)

A Guedel airway modifed with an inflatable balloon at is distal end and a 15mm connector at its proximal end which attaches to a self-inflating bag resuscitator. With the balloon down can be used a regular oral airway; with the balloon up it seals the hypopharynx and is connected directly to the bag. Does not provide protection against aspiration (neither does the face mask); and is currently not approved for emergency use. References: Rees SG. Gabbott DA. Use of the cuffed oropharyngeal airway for manual ventilation by nonanaesthetists. Anaesthesia. 54(11):1089-93, 1999. Heringlake M. Doerges V. Ocker H. Schmucker P. A comparison of the cuffed oropharyngeal airway (COPA) with the laryngeal mask airway (LMA) during manually controlled positive pressure ventilation. Journal of Clinical Anesthesia. 11(7):590-5, 1999. Heringlake M. Doerges V. Ocker H. Schmucker P. A comparison of the cuffed oropharyngeal airway (COPA) with the laryngeal mask airway (LMA) during manually controlled positive pressure ventilation. Journal of Clinical Anesthesia. 11(7):590-5, 1999.

Laryngeal Mask Airway

Easier to use and more effective ventilation than the face mask: Alexander R, Hodgson P, Lomax D, Bullen C. A comparison of the laryngeal mask airway and Guedel airway, bag and facemask for manual ventilation following formal training. Anaesthesia. 1993;48:231-234. Significantly easier for unskilled personnel to insert than a laryngoscope (following manikin only laryngoscopy instruction): Davies PRF, Tighe SQM, Greenslade GL, Evans GH. Laryngeal mask airway and tracheal tube insertion by unskilled personnel. Lancet. 1990;336:977-979. Reinhart DJ, Simmons G. Comparison of placement of the laryngeal mask airway with endotracheal tube by paramedics and respiratory therapists. Ann Emerg Med. 1994;24:260-263. Martin PD, Cyna AM, Hunter WAH, Henry J, Ramayya GP. Training nursing staff in airway management for resuscitation: a clinical comparison of the facemask and laryngeal mask. Anaesthesia.1993;48:33-37. Speed to ventilation with LMA by unskilled personnel averaged 40 seconds in a study of paramedic trainees, and was also more successful than laryngoscopy: Pennant JH. Walker MB. Comparison of the endotracheal tube and laryngeal mask in airway management by paramedical personnel. Anesthesia & Analgesia, 1992; 74(4):531-4.

LMA as a rescue device for failed intubation: Parmet JL, Colonna-Romano P, Horrow JC, et al. The laryngeal mask airway reliably provides rescue ventilation in cases of unanticipated difficult tracheal intubation along with difficult mask ventilation. Anesthesia & Analgesia. 87(3):661-5, 1998. This study looked at failed laryngoscopy in a two-year period in OR setting. 25 cases of failed airways, LMA worked in 94% (CI 77-100%), flexible fiberoptic bronchoscopy 50% (CI 0-100%), TTJV 33% (CI 0-100%), and retrograde intubation and cricothyrtomy worked in 100% (CI 33-100%) of cases [wide confidence intervals because of low numbers]. Median number of laryngoscopies was 4, range 1-9! Martin SE, Ochsner MG, Jarman RH, et al. Use of the laryngeal mask airway in air transport when intubation fails. Journal of Trauma-Injury Infection & Critical Care. 47(2):352-7, 1999. Aye T, Milne B, Use of the laryngeal mask prior to definitive intubation in a difficult airway: A case report. J Emerg Med. 1995; 13: 711-714.

Use of the LMA for airway rescue in cases of supraglottic pathology: Brimacombe J, Berry A, van Duren P. Use of a size 2 laryngeal mask airway to relieve life threatening hypoxemia in an adult with quinsy. Anaesth Intens Care 1993; 21: 475-476. King CJ, Davey AJ, Chandradeva K. Emergency use of the laryngeal mask airway in severe upper airway obstruction caused by supraglottic oedema. Br J Anesth 1995; 75: 785-786.

Intubation through the LMA: Heath, M.L. and Allagain, J. Intubation through the laryngeal mask. A technique for unexpected difficult intubation. Anaesthesia 46:545-548, 1991. Smith, J.E. and Sherwood, N.A. Combined use of laryngeal mask airway and fibreoptic laryngoscope in difficult intubation. Anaesthesia & Intensive Care 19:471-472, 1991. Benumof, J.L. Use of the laryngeal mask airway to facilitate fiberscope-aided tracheal intubation. Anesthesia & Analgesia 74:313-315, 1992.

Intubating laryngeal mask accepts a larger tracheal tube (8.0 mm) than the LMA (6-7.0 mm), and handle allows manipulation which aids tracheal tube placement. ILMA very expensive compared to disposable LMA (Fastrach $495 each vs. Unique $36 each). ILMA probably harder to use with fiberoptic scope because of more severe angle. Although manufacturer recommends special ET tube (supplied with unit) for ILMA, standard tube can be used as long as it inserted with curve reversed. References for ILMA: Joo H. Rose K. Fastrach--a new intubating laryngeal mask airway: successful use in patients with difficult airways. Canadian Journal of Anaesthesia. 45(3):253-6, 1998. Fukutome T. Amaha K. Nakazawa K. Kawamura T. Noguchi H. Tracheal intubation through the intubating laryngeal mask airway (LMA-Fastrach) in patients with difficult airways . Anaesthesia & Intensive Care. 26(4):387-91, 1998. Rosenblatt WH. Murphy M. The intubating laryngeal mask: use of a new ventilating-intubating device in the emergency department. Annals of Emergency Medicine. 33(2):234-8, 1999. ILMA simplicity and ease of placement meets the basic requirement for a rarely used rescue device: Levitan RM. Ochroch EA. Stuart S. Hollander JE. Use of the intubating laryngeal mask airway by medical and nonmedical personnel.American Journal of Emergency Medicine. 18(1):12-6, 2000. ILMA in inexperienced hands may not be more effective at intubation than laryngoscopes, however ventilation clearly easier than mask ventilation: Avida MS, Harvey A, Chitkara N, Ponte J. The intubating laryngeal mask airway compared with direct laryngoscopy. British Journal of Anesthesia, 1999; 83: 615-17.

LMA patent expires next year—expect a flood of cheap imtitations with prices $10 or less per disposable unit.

Cricothyrotomy

Cricothyrotomy should never be started with the patient already hypoxic or in arrest—outcome is terrible and time to ventilation is longer than with a rescue device: Spaite DW. Joseph M. Prehospital cricothyrotomy: an investigation of indications,technique, complications, and patient outcome. Annals of Emergency Medicine. 19(3):279-85, 1990. Eisenburger P. Laczika K. List M. Wilfing A. Losert H. Hofbauer R. Burgmann H. Bankl H. Pikula B. Benumof JL. Frass M. Comparison of conventional surgical versus Seldinger technique emergency cricothyrotomy performed by inexperienced clinicians. Anesthesiology. 92(3):687-90, 2000. Most EM residents will not perform a cricothyrotomy in their training: Chang RS. Hamilton RJ. Carter WA. Declining rate of cricothyrotomy in trauma patients with an emergency medicine residency: implications for skills training. Academic Emergency Medicine. 5(3):247-51, 1998 .

Rapid four-step technique faster than traditional method, but may have higher complication rates. Rapid technique uses #20 blade (instead of # 11), incision is made simultaneously through skin and cricothyroid membrane, traction is on cricoid ring (not thyroid cartilage) in downward (not upward) direction. The rapid technique also does not require use of a dilator if the initial incision with the larger blade has been made correctly. Davis DP. Bramwell KJ. Vilke GM. Cardall TY. Yoshida E. Rosen P. Cricothyrotomy technique: standard versus the Rapid Four-Step Technique. Journal of Emergency Medicine. 17(1):17-21, 1999. DiGiacomo JC. Angus LD. Gelfand BJ. Shaftan GW. Cricothyrotomy technique: standard versus the rapid four step technique. Journal of Emergency Medicine. 17(6):1071-3, 1999. Holmes JF. Panacek EA. Sakles JC. Brofeldt BT. Comparison of 2 cricothyrotomy techniques: standard method versus rapid 4-step technique. Annals of Emergency Medicine. 32(4):442-6, 1998.

Percutaneous methods are less intimidating to perform, but have not been shown to be faster, nor more efficacious: Eisenburger P. Laczika K. List M. Wilfing A, et al. Comparison of conventional surgical versus Seldinger technique emergency cricothyrotomy performed by inexperienced clinicians. Anesthesiology. 92(3):687-90, 2000. Chan TC. Vilke GM. Bramwell KJ. Davis DP. Hamilton RS. Rosen P. Comparison of wire-guided cricothyrotomy versus standard surgical cricothyrotomy technique. Journal of Emergency Medicine. 17(6):957-62, 1999.