DIFFICULT AIRWAY MANAGEMENT
From the Cleveland Clinic’s 10th Annual Management of the Difficult Airway
| LASERS AND THE AIRWAY —Sawsan Alhaddad, MD, Staff Anesthesiologist, Division of Anesthesiology
and Critical Care Medicine, Cleveland Clinic, Cleveland, OH
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| Introduction: Einstein first person to describe laser; acronym for light amplification by stimulated emission of
radiation; first description of lasers appeared in 1960s
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| Ordinary light vs laser light: ordinary light multidirectional; laser light collimated; wavelength range of visible
light 390 nm to 800 nm, ultraviolet light <390 nm, infrared light >800 nm; laser light almost purely one wavelength;
all waves parallel (ie, collimated; beam can be directed long distance) and coherent
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| Laser mechanism: laser medium (eg, gas, liquid, solid) contained in chamber; excitation device pumps energy
into medium and causes electrons and molecules to be excited (known as population inversion; electrons and
molecules at higher level of energy and emit more photons); excitation enlarged or magnified by mirrors located
at either end of laser medium; partial mirror intermittently allows beam to be emitted; cooling mechanism
also necessary
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| Laser medium: determines name of laser (eg, CO2 , neodymium-doped yttrium aluminum garnet [Nd:YAG],
KTP/532, argon), wavelength, color, and effect on tissues (eg, CO2 laser not suitable for coagulation; argon
and KTP laser suitable for retina, skin lesions, and coagulation of blood vessels)
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| Absorption characteristics: CO2 laser—superficial effect; most useful for airway procedures (deeper tissue unaffected);
extinction length <0.03 mm; no sequelae and little scarring; coagulates blood vessels ≤0.5 mm; Nd:YAG
laser—not absorbed by pigment tissue (mass of affected tissue 1000 times greater than with CO2 laser); produces
edema and swelling; delayed complications possible (effects may not appear on first day); used to debulk
large tumors in airway, trachea, and bronchi; coagulates blood vessels ≤5 mm; argon laser—absorbed by hemoglobin
and melanin; frequently used to coagulate blood vessels; also used for retina and skin lesions
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| Articulated arms vs fiberoptics: CO2 laser requires rigid structure or articulated arm with mirrors; all other lasers
use coaxial fibers to direct beam into tissue; beam can also be placed through fiberoptic bronchoscope or attached
to handle and applied to tissue
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| Effect of intracellular temperature: at 400°C, carbonization; at 100°C, cellular water boils; at lower temperatures,
cell protein coagulates and denatures
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| Laser mishaps: electric shock—avoid standing water on floor; smoke inhalation—special masks necessary to trap
particles; also use smoke evacuators close to field; accidental tissue exposure—health care worker and patient
at risk; patient risks include skin burns, mucosal burns, perforation of blood vessel, pneumothorax, and pneumomediastinum;
protect tissue around field to prevent accidental burn (cover area with wet cottonoid [including
eyes]); health care worker risks include skin and eye exposure (wear protective goggles; contact lenses
ineffective); fires—caused by combination of O2 source, source of ignition (eg, laser), and flammable material
(eg, cottonoid, endotracheal tube [ETT], patient’s tissue)
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| Surgical requirements: access to lesion; still field; decreased risk for fire; adequate time
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| Anesthesia requirements: provide anesthesia; access to airway; decreased risk for fire; prevent aspiration
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 | Laryngeal cases: ETT—advantages include more time, secured airway, and lack of constant interruptions;
disadvantages include limited access and increased risk for fire (introducing flammable material into airway;
protect tube [using adhesive metallic tape] or use more resistant tube; reduce O2 mixture; avoid N2 O;
place saline in cuff); types of tubes available—polyvinyl chloride (PVC; more easily ignited but easier to extinguish;
produces large amount of toxins when burning) or red rubber (more resistant to laser, but once ignited,
continues to burn and produce large amount of smoke); found safe for CO2 and KTP lasers only; no
ETT—advantages include reduced risk for fire, better surgical access, easier use in pediatrics, use of higher
fraction of inspired O2 (FiO2 ); disadvantages include unsecured airway, higher risk for barotrauma with jet
ventilation, higher risk for aspiration, and impracticality of inhalation agents; suspension laryngoscope—
spontaneous respiration (insufflating inhalation agent down channel); apneic oxygenation; manual or high-
frequency jet ventilation; transtracheal jet ventilation; stainless steel laser cannula—2 channels; high-frequency
jet ventilation
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| Endobronchial cases: using rigid bronchoscopy (easier) or fiberoptic bronchoscopy; methods of ventilation—
circuit and bag; jet ventilation; high-frequency jet ventilation; spontaneous respiration; Saunders injector;
Nd-YAG laser photoresection—indications include unresectable tumor, radiation insensitivity, and failed
chemotherapy; palliative procedure; total obstruction of one of bronchi and postobstruction pneumonitis
frequent; location of lesion determines airway management; use of stainless steel laser cannula effective;
laryngeal mask airway (LMA)—Keller study shows shaft of classic LMA (silicone) more resistant to KTP and
Nd-YAG laser; cuff of disposable LMA more resistant; filling cuff with methylene blue increases resistance;
metal, wire, lettering, or blood on cuff decreases resistance; Pandit study recommends avoiding
metal on reinforced LMA
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| Nd-YAG laser therapy: immediate complications include perforation of major vessels, hemorrhage from lesion,
endobronchial fire, pneumomediastinum, pneumoperitoneum, and cerebral air embolism
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| Precautions during laser use: post signs indicating laser usage; reduce traffic; communicate; use smoke evacuators;
use appropriate mucous membrane, eye, and skin protection; modify anesthetic technique; electrical precautions
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| Fire: stop ventilation; disconnect circuit; pull burning material out; douse area with water; extinguish fire; continue
anesthetic; resume ventilation with 100% O2 ; assess damage (perform bronchoscopy); admit and monitor patient;
give respiratory support; steroids may be necessary
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| DIFFICULT AIRWAY AND PEDIATRICS —Julie Niezgoda, MD, Chairman, Pediatric Anesthesia, Cleveland
Clinic, Cleveland, OH
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| Developmental anatomy: infant tongue relatively large; epiglottis and laryngeal inlet C1 to C2 in infants, C2 to
C3 by age 3 yr, and C5 to C6 in adults; infants and adolescents have shedding of deciduous teeth; larynx more
cephalad (airway can “flop over” arytenoids and obstruct view); cricoid only complete cartilage in laryngotracheobronchial
tree (small decreases in airway size result in large increases in resistance); cartilaginous ribs
tend to be problematic in respiratory distress; ventilation primarily diaphragmatic; intercostal muscles and diaphragm
are fast twitch (type II muscle fibers) and may be factor in development of fatigue and respiratory
failure; abdominal viscera bulky and can hamper diaphragmatic excursion
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| Ventilation: higher incidence of laryngospasm and potential for upper respiratory infection; alveolar ventilation
doubled in neonate, compared to adult; increased O2 consumption (6 to 8 mL/kg per minute in infant vs 3 mL/
kg per minute in adult) and increased CO2 production; closing volume tends to impinge on tidal volume; positive
end-expiratory pressure (PEEP) essential
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| Cardiovascular issues: chest compressions frequently used in child with difficult airway; normal heart rate (HR)
120 to 130 per min in 3-yr-old; blood pressure (BP) dependent on cardiac output and systemic vascular resistance;
cardiac output direct relationship between stroke volume and HR; child born with less contractile tissue
in left ventricle, therefore, unable to increase stroke volume to maintain BP; bradycardia in child equivalent to
ventricular fibrillation in adult (multiple foci and no ejection); speaker cognizant of HR; performs chest compressions
at onset of problems; trust monitor readout (eg, O2 saturation) and act appropriately (listen, auscultate,
ensure good HR)
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| Cooling: hypothermic child releases norepinephrine, resulting in pulmonary vasoconstriction, increased pulmonary
artery pressure, right-to-left shunting, and hypoxia
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| Positioning: place circular donut to level child before intubation; look at side view of child; know history and
planned procedure
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| Congenital lesions: laryngomalacia most common and most benign (but can sound “awful”); if parent unconcerned,
probably not acute airway problem; maxillofacial surgery can be difficult in child with cystic hygroma,
craniofacial anomaly, or Goldenhar’s syndrome
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| Acquired lesions: includes supraglottitis, croup (laryngotracheobronchitis), and foreign body (FB) aspiration
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| Epiglottitis (supraglottitis): life-threatening illness; affects older children; presenting symptoms include
odynophagia, dysphonia, and drooling; parents look fearful; child prefers to sit upright in “tripod” (sniffing)
position (to maintain airway by aligning oral, pharyngeal, and laryngeal axis); “if you really suspect epiglottitis,
[child] should be brought emergently to the OR”; requires involvement of multidisciplinary team; obtain
thorough but rapid history and physical examination; prepare for long induction
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| Human papillomavirus (HPV): number one sexually transmitted disease; ≈30% of adolescents infected; presentation
variable and includes hoarseness and stridor; papilloma located mostly above vocal cords, but can be
subglottic (infrequent in trachea and bronchus); speaker uses shaving device instead of laser to remove papilloma
(less trauma)
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| FB aspiration: causes >300 deaths in children per year; laryngeal and tracheal FB manifest as cough and dyspnea;
more common in younger child (often explore small objects orally; initial choking may be unwitnessed);
may have normal physical examination or normal chest x-ray; may be misdiagnosed as croup, asthma, or
pneumonia; complications of late diagnosis include pneumonia, atelectasis, and obstructive emphysema;
management issues include determining whether removal urgent or emergent, deciding on intravenous vs inhalational
induction, advantages and disadvantages of controlled ventilation vs spontaneous ventilation (speaker
prefers controlled ventilation)
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| Laryngeal mask airway (LMA): have age-specific equipment available; know available devices; oral airway may
be necessary (should cover from mouth to ramus of mandible; if too short, can obstruct airway, if too long
may cause child to cough and choke); position child by aligning oral, pharyngeal, and laryngeal axes; Howland
lock changes angle of laryngoscope blade (effective in adults and children; inexpensive); insert LMA inflated,
place facing posteriorly, then rotate while pushing into hypopharynx (increases success rate to 99%);
should view apertures, epiglottis, and vocal cords; then perform blind intubation and fiberoptic-aided intubation;
multiple sizes (when using LMA in pediatrics, use largest LMA that will fit; size 1 shown to cause obstruction
and increased laryngospasm; speaker uses swivel whenever possible, due to increased O2
consumption); consider LMA with oropharyngeal hemorrhage
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| Endotracheal tube: speaker always uses cuffed ETT
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| Fiberoptic intubation: do everything necessary to keep child oxygenated; speaker begins with mask induction
(not LMA-assisted); maintain PEEP when mask ventilating (due to increased chance of atelectasis); after documenting
ventilation, give muscle relaxant; then place small tube in other nostril (or oropharynx) to maintain
oxygenation (ultrathin scope has no suction port to insufflate O2 or suction through; have assistant pull tongue
forward); Ovassapian airway or oral airway may be used, but sometimes too large; advance scope through vocal
cords, use Seldinger technique for ETT, and document end-tidal CO2
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Educational Objectives
| The goal of this program is to educate the listener about the use of lasers in airway/ventilation management and
difficult airway management in pediatrics. After hearing and assimilating this program, the participant will be
better able to:
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| 1. Differentiate the absorption characteristics of various types of laser media.
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| 2. Examine the use of lasers in laryngeal and endobronchial airway management cases.
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| 3. Review the anatomic and physiologic differences in the pediatric patient and how they affect airway
management.
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| 4. Review the clinical and laboratory presentation of supraglottitis, croup, human papillomavirus, and foreign
body in the pediatric patient.
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| 5. Discuss the management options of acquired airway difficulties unique to the pediatric patient.
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Discussed on This Program
Epinephrine (several trade names)
Midazolam HCl [Versed]
Nitrous oxide (N2 O)
Propofol [Diprivan]
Suggested Reading
Alhaddad S et al: Helium and lower oxygen concentration do not prolong tracheal tube ignition time during potassium
titanyl phosphate laser use. Anesthesiology 80:936, 1994; Bourgain JL et al: Transtracheal high frequency
jet ventilation for endoscopic airway surgery: a multicentre study. Br J Anaesth 87:870, 2001; Butler MG et al:
Specific genetic diseases at risk for sedation/anesthesia complications. Anesth Analg 91:837, 2000; Cressman
WR et al: Diagnosis and management of croup and epiglottitis. Pediatr Clin North Am 41:265, 1994; Dalmeida RE
et al: Total airway obstruction by papillomas during induction of general anesthesia. Anesth Analg 83:1332,
1996; Fitzgerald D et al: Nebulized budesonide is as effective as nebulized adrenaline in moderately severe
croup. Pediatrics 97:722, 1996; Fried MP et al: Comparative analysis of the safety of endotracheal tubes with the
KTP laser. Laryngoscope 99:748, 1989; Geffin B et al: Flammability of endotracheal tubes during Nd-YAG laser
application in the airway. Anesthesiology 65:511, 1986; Infosino A: Pediatric upper airway and congenital anomalies.
Anesthesiol Clin North America 20:747, 2002; John SD et al: Stridor and upper airway obstruction in infants
and children. Radiographics 12:625, 1992; Jones S, Raffles A: Pediatric perioperative cardiac arrest (POCA) registry.
Qual Saf Health Care 11:252, 2002; Keller C et al: Liability of laryngeal mask airway devices to thermal
damage from KTP and Nd:YAG lasers. Br J Anaesth 82:291, 1999; Medici G et al: Anesthesia for endobronchial
laser surgery: a modified technique. Anesth Analg 88:298, 1999; Morray JP et al: Anesthesia-related cardiac arrest
in children: initial findings of the Pediatric Perioperative Cardiac Arrest (POCA) Registry. Anesthesiology
93:6, 2000; Mu L et al: The causes and complications of late diagnosis of foreign body aspiration in children.
Report of 210 cases. Arch Otolaryngol Head Neck Surg 117:876, 1991; Murat I: Cuffed tubes in children: a 3-year
experience in a single institution. Paediatr Anaesth 11:748, 2001; Pandit JJ et al: KTP laser-resistant properties of
the reinforced laryngeal mask airway. Br J Anaesth 78:594, 1997; Rabb MF et al: Blind intubation through the laryngeal
mask airway for management of the difficult airway in infants. Anesthesiology 84:1510, 1996; Sosis MB
et al: Saline-filled cuffs help prevent laser-induced polyvinylchloride endotracheal tube fires. Anesth Analg
72:187, 1991; Sosis MB: Evaluation of five metallic tapes for protection of endotracheal tubes during CO2 laser
surgery. Anesth Analg 68:392, 1989; Walker P et al: Croup, epiglottitis, retropharyngeal abscess, and bacterial
tracheitis: evolving patterns of occurrence and care. Int Anesthesiol Clin 30:57, 1992; Wolf GL et al: Flammability
of endotracheal tubes in oxygen and nitrous oxide enriched atmosphere. Anesthesiology 67:236, 1987.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lecturers to disclose any significant
financial relationship with the manufacturer or provider of any commercial product or service discussed.
For this issue, the faculty reported nothing to disclose.
Drs. Alhaddad and Niezgoda spoke at the 10th Annual Management of the Difficult Airway, presented November
12-13, 2005, by the Cleveland Clinic Foundation, and held in Cleveland, OH. The Audio-Digest Foundation
thanks the speakers and the sponsors for their cooperation in the production of this program.
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