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OJHAS Vol. 10, Issue 2:
(Apr-Jun 2011) |
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| The Application
of Airtraq (fibreoptic intubation device) to Otolaryngology |
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Dulani Mendis, ENT SpR, West
Midlands Deanery, Dept. of ENT
Surgery, Birmingham Children’s Hospital NHS Foundation Trust, Steelhouse
Lane, Birmingham B4 6NH,
John Oates, Consultant Otolaryngologist, Dept. ENT
Surgery, Queen’s Hospital, Belvedere Road, Burton-on-Trent, DE13 0RB. |
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Address for Correspondence |
Dept. of ENT
Surgery,
Birmingham Children’s Hospital NHS Foundation Trust,
Steelhouse
Lane,
Birmingham B4 6NH.
E-mail:
dulanimendis@yahoo.com |
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Mendis D, Oates J.
The Application
of Airtraq (fibreoptic intubation device) to Otolaryngology. Online J Health Allied Scs.
2011;10(2):16 |
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Submitted: June 24,
2011; Accepted: Jul 16, 2011; Published: Jul 30, 2011 |
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| Abstract: |
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The anaesthetic
laryngoscope Airtraq is designed for the difficult airway. This disposable laryngoscope
requires minimal cervical manipulation
and unlike other common anaesthetic larynmgoscopes contains a channel
for the guidance of an endotracheal tube. This could also be used
for diagnosis and biopsy under a general anaesthetic or potentially
under a local anaesthetic in an outpatient setting for biopsies or the
removal of hypopharyngeal foreign bodies via flexible biopsy forceps
obviating the need for a general anaesthetic. Thus
Airtraq could be included in the armoury of
pre-existing direct laryngoscopes because of its virtue of minimal airway
manipulation.
Key Words:
Difficult intubation; Laryngoscopy
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Difficult endotracheal
intubation is often associated with a difficult direct laryngoscopy
for the Otolaryngologist and subsequent poor visualisation of the larynx.
A difficult intubation is defined as “more than three attempts
to intubate in 10 minutes of time” 1, or whereby “it
is not possible to visualise any portion of the vocal cords with conventional
laryngoscopy” or “intubation requires more than one attempt, a change
in blade, an adjunct to direct laryngoscopy or use of alternative devices”.2
The difficult airway is usually assessed as being Cormack and Lehane Grade 3 and 4 or Mallampati Class 3 and 4 (Figure
1).
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Figure 1: (A) Mallampati
classification: Class 1 – visualisation of the soft palate, Class
2 – complete visualisation of the uvula, Class 3 – visualisation
of the base of the uvula, Class 4 – soft palate is not visible at
all. (B) Laryngoscopy
according to the Cormack and Lehane classification: Grade I – most
of the glottis visible, Grade II – only the posterior extremity of
the glottis visible, Grade III – only the epiglottis visible (none
of the glottis seen), Grade IV- neither epiglottis or glottis visible.
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Other contributory
patient factors may be morbid obesity and cervical spine pathology e.g.
trauma and/or degenerative disease causing instability (Rheumatoid Arthritis).
Successful tracheal intubation achieved by obtaining a good glottic
view, requires alignment of three optical axes corresponding to the
oral, pharyngeal and laryngeal planes (Figure 2).
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Figure 2:
Diagram illustrating
the oral, pharyngeal and laryngeal axes, in-order to to obtain an optimal
view prior to intubation a degree of cervical manipulation is required
for the alignment of these axes.
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During routine
laryngoscopy, a degree of manipulation of the neck is required to align
these axes. Excessive manipulation due to an unexpected difficult
airway can result in delayed intubation (hypoxia), cervical injury,
soft tissue injury and increased risk of dental trauma. In patients
with cervical spine trauma the concomitant manual in-line axial stabilisation
prevents head extension and neck flexion further limiting optimal visualisation
of the glottis.
Alternative
methods for intubating difficult cases include awake-fibreoptic intubation,
with the gold standard being a fibreoptic bronchoscope. This is
a skilled technique with a steep learning curve. The procedure
can take some time and the view may be compromised by blood and secretions.
The instrument is weighty and expensive, it requires a separate light
source or video stack and the instrument can present as a source of
infection if not properly sterilised. Awake intubation, is performed
in a controlled manner with an expected difficult intubation.
In the case of a crash intubation the Otolaryngologist may be called
upon to intubate with a side splitting Negus-type laryngoscope or as
a last resort perform an emergency surgical airway (cricothyroidotomy
or tracheostomy).
Other anaesthetic
laryngoscopes for difficult intubations in the anaesthetised patient
are the McCoy levering laryngoscope blade (Penlon Ltd, Abingdon, UK),
Bullard laryngoscope (Circon ACMI, Stamford, CT), the LMA C-Trach (LMA
North America, San Diego, CA) and the Glidescope (Saturn Biomedical,
Burnaby, British Colombia, Canada). These are essentially anaesthetic
laryngoscopes, which provide an improved view for intubation but not
necessarily the equivalent view obtained with a direct laryngoscope
(Negus, Kleinsessor, Lindholm) required in Otolaryngology for biopsy
purposes or removal of laryngeal/hypopharyngeal foreign bodies.
The Airtraq
laryngoscope, (Inventor: Pedro Acha, Gandarias, produced by Prodol
Meditec, Spain) is a new device which has recently become commercially
available in the United Kingdom. It is a disposable device with
an anatomically shaped blade. This contains a series of lenses,
prisms and mirrors that transfer the image from the illuminated blade
tip to the proximal viewfinder. The blade incorporates a endotracheal
tube (ETT) channel on the right side to guide the ETT and any type of
ETT can be used (standard, reinforced etc.)
The light is
battery powered and the battery box is located in the main body of the
Airtraq device. There are two sizes selected depending on patient
weight and size of ETT to be used; regular size - maximum blade thickness
of 17.5 mm (ETT 7.0-8.5) and small – maximum blade thickness of 15.5mm
(ETT 6.0-7.5), (Figure 3A, 3B). Two further Airtraq versions now
exist for nasotracheal and double lumen endobronchial intubations.
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Figure 3:
(A) Photo of
the disposable Airtraq device. (B) Photo demonstrating
the detachable view finder and battery pack. |
There is an
anti-fog system and an available clip-on video system to allow viewing
on to a monitor with a recording facility. The device requires
30-60 seconds to reach its maximal light and it can be passed, and the
patient intubated with the neck in a neutral position (no manipulation
of the neck is required) and so a good view of the glottis is obtained
without the need for aligning the three axes due to the inherent prism
system.
Airtraq has
been used in patients with cervical spine trauma3, morbidly
obese patients4, patients requiring rapid sequence induction5,
intubation in the upright position6, awake intubations7
and intubations without muscle relaxants. Maharaj, et al (2006)8
compared the ease of learning intubation with the Airtraq device with
a Mackintosh laryngoscope. The study concluded that the Airtraq
laryngoscope required less operator skill to use. It had a shorter
learning curve, was able to provide a good view of the larynx with minimal
airway manipulation, reduced intubation time and was associated with
less dental trauma.
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Discussion: Application to
Laryngology |
The use of
the Airtraq device in Laryngology maybe relevant for the difficult to
intubate patient as the hypopharyngeal/laryngeal view is similar to
that obtained with a direct laryngoscope with the additional advantage
of less airway manipulation whilst primarily being used as an intubating
tool. To expose the glottis the device can either be located at
the valecullar or under the epiglottis. Biopsies of relevant areas
could also be taken, which is more feasible with shorter versions of
flexible biopsy forceps (e.g those used for bronchoscopy), in order
to follow the exaggerated curvature of the laryngoscope (Figure 4).
There does not appear to be a suitably curved rigid instrument at present.
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Figure 4: Photo demonstrating
the Airtraq device with the use of a flexible biopsy forcep guided through
the intubation channel for the proposed purpose of foreign body removal
and biopsies
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The device
has been described for use in awake patients; this could be applied in
the outpatient setting for laryngeal biopsies and the effective removal
of hypopharyngeal foreign bodies with adequate local anaesthesia
using flexible forceps and an appropriate flexible suction catheter.
Mackintosh laryngoscopes have anecdotally been used previously for foreign
body removal in an awake patient but this is usually a difficult, uncomfortable
and unsuccessful procedure. This could prevent the need for a
general anaesthetic (especially relevant to patients with multiple co-morbidities,
American Society of Anesthesiology grade 3 and upwards) and the cost
of a hospital admission.
The Airtraq
is single use; the plastic viewfinder and battery box are detached from
the blade, which is disposable. Disposable items although initially
expensive when introduced to the market are desirable in terms of reducing
the risk of transmission of prion proteins (Creutzfeldt Jacob disease).
Financially,
the four Airtraq variants are costed at £35 excluding VAT (Fannin UK
Limited, Reading). The video system is an optional add-on consisting
of a clip-on camera and wireless receiver. In terms of the curved
instruments standard flexible bronchoscopy biopsy forceps are costed
at £10 each excluding VAT in boxes of ten
(Diagmed Healthcare, Yorkshire, UK) a shorter version of these
(currently 110cm in length) would be the most appropriate.
Our review
comments on the application of a new intubating device currently used
by Anaesthetists for the difficult airway, to Otolaryngology for diagnostic
purposes in such cases and on its potential use for the removal of hypopharyngeal
foreign bodies in an outpatient scenario, obviating the need for a general
anaesthetic.
We propose
the importance of including this device in the armoury of pre-existing
direct laryngoscopes because of its virtue of minimal airway manipulation.
- American
Society of Anesthesiologists. Practice guidelines for management of
the difficult airway. A report by the American Society of Anesthesiologists
Task Force on Management of the Difficult Airway. Anesthesiology. 1993;78(3):597-602.
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American
Society of Anesthesiologists. Practice Guidelines for Management of
the Difficult Airway. An Updated Report by the American Society
of Anesthesiologists Task Force on Management of the Difficult Airway.
Anesthesiology. 2003;98(5):1269–1277.
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Maharaj CH,
Buckley E, Harte BH, Laffey JG. Endotracheal Intubation in Patients
with Cervical Spine Immobilization. A Comparison of Mackintosh and Airtraq
Laryngoscopes. Anesthesiology. 2007;107(1):53-59.
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Dhonneur
G, Ndoko SK, Amathieu R, Housseini LE, Polliand C, Tual
L. A comparison of two techniques for inserting the Airtraq laryngoscpe
in morbidly obese patients. Anaesthesia. 2007;62:774-777.
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Dhonneur
G, Ndoko SK, Amathieu R, Housseini LE, Poncelet C, Tual
L. Tracheal Intubation Using the Airtraq in Morbid Obese Patients
Undergoing Emergency Cesarean Delivery. Anesthesiology. 2007;106(3):629-630.
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Ndoko SK, Amathieu R, Tual L, Polliand C, Kamoun W, Housseini
LE, Champault G, Dhonneur G. Tracheal intubation of morbidly obese patients: a randomised trial comparing
performance of Macintosh and Airtraq laryngoscopes. British Journal
of Anaesthesia. 2008;100(2):263-268.
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Suzuki A,
Toyama Y, Iwasaki H. Correspondence: Airtraq for awake tracheal
intubation. Anaesthesia. 2007;62:744-755.
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Maharaj CH,
Costello JF, Higgins BD, Harte BH, Laffey JG. Learning
and performance of tracheal intubation by novice personnel: a comparison
of the Airtraq and Mackintosh laryngoscope. Anaesthesia. 2006;61:671-677.
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