Module 14
Advanced Airway Techniques
Part 2 - New Generation Supraglottic Ventilatory Devices
Classification of Supraglottic Ventilatory Devices
CUFFED PERIPHARYNGEAL SEALERS - INTUBATING LARYNGEAL AIRWAYTM
History
The Intubating Laryngeal Airway™
(ILA, Cookgas L.L.C., St. Louis, MO) distributed by Mercury
Medical (Clearwater, FL) is a new, FDA-approved, reusable
hypercurved intubating laryngeal airway invented by Dr. Daniel
Cook who spent over 8 yrs in its development. The ILA was
introduced into clinical practice in December of 2004 for airway
management as a SGA or as a conduit for endotracheal intubation.
Device Description
The ILA is manufactured of
medical grade silicon and is 100% latex free. There are ridges
located in both the airway tube and the mask. The ridges below
the airway connector were designed to improve the tube seal.
They also allow for easy removal of the connector during
intubation through the device. The airway tube of the ILA is
hypercurved to approximate the anatomy of the oral-pharyngeal
passage  designed to eliminate the tendency to “over bend” and
kink the airway tube (Figure 6).
The large oval mask cavity allows
intubation using standard ETs (sizes 5.0-8.5 mm). There is a
keyhole-shaped airway outlet designed to direct the ETs toward
the laryngeal inlet. It also creates ample space for other
medical instruments used for intubation. There are three
internal ridges located in the distal portion of the mask that
approximate the anatomic shape of the posterior pharynx which
are designed to create increased airway stability, smooth
insertion and improved airway alignment. Once the ILA cuff is
inflated, these ridges move against the posterior larynx and
improve the anterior mask seal, thus helping to isolate the
esophagus and reduce the potential for aspiration.
There are 3 ILA sizes available
(2.5, 3.5, 4.5). Generally, the 2.5 is used in children and
adolescents 20-50 kg (smallest size ET 5.0 mm), the 3.5 is used
in small adults (50-70 kg) and the 4.5 is used on large adults
(70-100 kg). They are available in ½ sizes since these fit a
broader range of patients.
 The removal following intubation
is accomplished with the Cookgas® ILA™ Removal Stylet (Figure 7). This stylet was specifically designed to be used in
conjunction with the ILA. The stylet stabilizes the previously
inserted ET, and allows for controlled removal of the ILA
without dislodging the ET from the trachea. It is manufactured
with polypropylene and can be used up to 10 times. It must be
cleansed in a detergent solution; it is not autoclavable, as is
the ILA. The ILA Removal Stylet consists of an adapter
connected to a rod. The adapter is tapered from bottom to top,
and has horizontal ridges and vertical grooves. The taper
allows the stylet to accommodate standard ETs in multiple sizes
(5.0-8.5 mm). It is designed with ridges and groves, each
serving a purpose. The ridges engage the ET in a firm, secure
grip, giving the user control of the ET during the ILA removal
process. The grooves allow spontaneous breathing patients
unimpeded air passage within the ET during the removal of the
ILA.
Insertion Technique & Device Removal
Prior to use, the integrity of
the cuff and inflation system should be checked by completely
deflating and reinflating the cuff with the maximum recommended
volume of air. All air should then be removed from the cuff by
active aspiration with a syringe, while pressing the anterior
portion of the mask onto a sterile flat surface. The posterior
portion of the device should be lubricated with a sterile,
water-based lubricant just prior to insertion.
Although not necessary, insertion
of the ILA is best accomplished with the patient’s head and neck
in the “sniffing position”, (e.g., neck flexed and head
extended). The use of jaw lift is recommended during
insertion. This maneuver elevates the epiglottis off the
posterior pharyngeal wall, thereby enhancing passage and seating
of the device. The ILA should be inserted using a similar
technique to the LMA, gently applying inward and downward
pressure, using the curvature of the ILA mask and airway tube as
a guide. Minimal manipulation may be necessary to turn the
corner into the upper pharynx. The device should be passed into
the hypopharynx until resistance is met. The cuff should then
be inflated with enough air (10-20 cc) until a proper seal is
obtained, or up to an intracuff press of 60 cm H2O.
Usually cuff inflation with 10 cc of air is sufficient to achieve
a seal. Connect the breathing system to the 15 mm connector and
assess adequacy of ventilation. If adequate ventilation is not
obtained, an “up-down” movement may clear a downfolding
epiglottis and remedy the situation. The ILA may now be
utilized for airway management as a SGA. A bite block should be
inserted alongside the tube and then taped in place in the usual
fashion.
If tracheal intubation is
necessary or desired, ILA positioning should be assessed for
optimal ventilation (i.e., easy airflow, higher tidal volumes).
Prior to intubation, the laryngeal musculature and vocal cords
must be relaxed, either by administration of a local anesthetic
or a muscle relaxant. The patient should be preoxygenated with
100% oxygen for 3-5 minutes. An appropriately sized ET (5.0-8.5
mm) should be prepared by completely deflating the ET cuff and
lubricating the external surface. It is important to deflate
the ET cuff completely to allow the ET to slide easily within
the ILA.
The ILA connector should then be
removed (but not discarded). The previously deflated and
lubricated ET should then be inserted through the ILA to a depth
of approximately 12-15 cm, depending on the ILA size. This will
place the distal tip of the ET at or just proximal to the
opening of the ILA airway tube within the mask cavity. There
are several acceptable methods that can now be employed to
further advance the ET into the trachea.
1. Fiberoptic technique
A FOB can be directly passed
through the ET and into the trachea by indirect visualization.
Once the carina is visualized, the ET can be passed through the
laryngeal inlet and into the proximal trachea, using the scope
as a guide. The ET cuff can then be inflated, the scope removed
and the ET connector replaced. Adequacy of ventilation should
be checked by capnography, adequate chest excursion and
auscultation of bilateral breath sounds.
2. Stylet technique
An intubation stylet
(Eschmann tracheal tube introducer or Frova intubation catheter)
can be passed through the ET and into the trachea. By gently
placing the fingers of the left hand over the cricoid cartilage,
the stylet may be felt as it passes through the cricoid ring.
Once the stylet passes into the trachea, simply advance the ET
over the stylet, through the laryngeal inlet and into the
trachea, using the intubation stylet as a guide. The ET cuff
can then be inflated, the stylet removed and the 15 mm ET
connector replaced. Adequate ventilation should then be
assessed, as above.
3. Blind technique
The ET should slowly be advanced
through the ILA in the direction of the laryngeal inlet. For
spontaneously breathing patients, the circuit can be attached to
the ET connector and capnography may be used as a guide to
successful tracheal placement. The Beck Airway Airflow Monitor
(Great Plains Ballistics, Lubbock) can also be used to
facilitate blind tracheal intubation. If resistance to further
advancement is encountered, repositioning of the ILA should be
performed. Once successful tracheal intubation has been
achieved, the ET cuff should be inflated and adequate
ventilation should be assessed, as noted previously.
Once proper position of the ET is
confirmed, the 15 mm connector of the ET should be removed and
the ILA Removal Stylet (tapered end first) should be placed into
the proximal end of the ET until the adapter fits snugly within
the ET. With firm inward pressure, rotate the stylet adapter in
a clockwise direction until the adapter firmly engages the ET.
The cuff of the ILA should be deflated to allow easier removal
of the device. While exerting an inward stabilizing force on
the stylet, slowly withdraw the ILA outward over the ET-ILA
stylet and out of the patient’s mouth. Unscrew the ILA stylet
from the ET in the counter-clockwise direction using outward
tension on the ILA stylet in order to disengage it from the ET.
The 15 mm connector can then be replaced on the ET and proper
position of the ET in the trachea reconfirmed.
Indications & Advantages
As previously mentioned, the ILA
was designed for airway management as a routine airway or as a
conduit for either blind, stylet guided or fiberoptically guided
endotracheal intubation. It should only be used in unconscious
or adequately topically anesthetized patients. It incorporates
design features which facilitate ease and reliability of
insertion. Its larger bowl enhances entry into the mouth and
passage along the oropharyngeal curve. The natural curve of its
leading edge facilitates passage behind the epiglottis and
arytenoid cartilages and into the upper esophageal inlet without
the need for special deflation techniques or insertion devices.
Each ILA accepts routinely used PVC ETs (2.5 can accommodate a
5.0-6.5 mm ET, 3.5 up to 7.5 mm ET and 4.5 up to 8.5 mm ET).
Unlike the ILMA, the ILA does not
necessarily require removal once it has been used as a conduit.
It can remain in place and later used as a bridge to extubation
during emergence. Additionally, 10 cc of air is usually
sufficient to inflate the cuff of the ILA, thus the same 10 cc
syringe routinely used for the ET cuff inflation can also be
used for the ILA cuff inflation. Lastly, the ILA Removal Stylet
is designed with grooves that allow spontaneous ventilation
within the ET during ILA removal, thus facilitating the
performance of awake or asleep intubation during spontaneous
ventilation with this device.
Disadvantages
The ILA is delivered
non-sterile. It should be washed thoroughly and autoclaved
prior to its use. The ILA Removal Stylet is also delivered
non-sterile and should be washed with soap and water and rinsed
with alcohol prior to its use. Similar to the ILMA, the ILA is
only available in sizes that do not allow intubation of infants
and young children. Additionally, when simply used as a SGA, it
should not be used in anesthetized patients at increased risk of
pulmonary aspiration of gastric contents, with poor lung
compliance or increased airway resistance, or with lesions of
the oropharynx or epiglottis. Its use as an emergency airway
device has not been studied.
Comparison to Face Mask Ventilation & Endotracheal Intubation
In theory, the use of the ILA
(when utilized as a SGA) should result in less dead space
ventilation and minimal gastric inflation, if reasonable airway
pressures are used. It allows the anesthesiologists to have
their hands free to perform other tasks. Compression of the
eyes and facial and infraorbital nerves is avoided, and
operating room pollution from vapors and anesthetic is less
likely.
Guide to Endotracheal Intubation
See insertion technique and device removal.
Medical Literature
Thus far, there is little
reported in the literature regarding the ILA. An observational
study was recently performed by Klein and Jones63
which involved 28 patients scheduled for gynecologic surgery.
The ILA was used for endotracheal intubation in 22 patients. A
fiberoptic was passed down the lumen of the ILA following
placement to evaluate its relationship to airway structures in
the first 20 patients and to facilitate endotracheal intubation
in selected patients. Blind passage of an ET was attempted in 6
of the first 20 patient and in all of the final 8 patients.
They determined that the ILA is effective as a device for airway
management and as a conduit for endotracheal intubation. The
ILA was successfully placed on the first attempt in 27 / 28
(96.4%) patients. They found that leaks during manual
ventilation could be corrected with slight withdrawal of the
device. Although the glottis was visualized in all patients
with the FOB, some degree of epiglottic downfolding was observed
on fiberoptic examination on most cases. The “Klein Maneuver”
describes the correction of epiglottic downfolding by jaw lift
and withdrawal of the ILA, followed by reinsertion. Intubation
using the ILA as a conduit was 100% successful using fiberoptic
guidance. Successful blind intubation was enhanced with the
flexible reinforced tracheal tube (Mallinkrodt, Inc.). Optimal
techniques for blind intubation, as well as the utility of the
device in difficult airways, requires further investigation.
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