Difficult airway management in the emergency department.

38 S. L. Orebaugh
often placed in an awkward position. Further, an overly
rigid stylet could cause retraction of the ETT out of the
glottis when the lightwand was withdrawn (63). Newer
models have improved upon visibility of the light as well
as the ergonomics of the device (66). The Trachlite
(Laerdahl, Long Beach, CA, USA), a two-piece lighted
stylet, allows the ETT to be placed without dislodging it
when the device is withdrawn, due to a retractable wire
stylet. A locking device for the proximal portion of the
ETT and an adjustable length stylet also represent significant
improvements of the Trachlite over earlier
lighted stylets (66).
In the OR, lighted stylet intubation has proven reliable
and highly successful. Ainsworth described intubation in
200 patients under general anesthesia within 60 sec,
whereas Weiss reported a series of 250 patients with
99% success in intubation using the lighted stylet
(65,67). In 950 surgical patients, use of the Trachlite
illuminating stylet was compared to direct laryngoscopy
for efficacy in tracheal intubation (66). Direct laryngoscopy
was found to require more time, produce more
complications, and result in a higher failure rate (3% vs.
1%). In 186 documented or suspected difficult airways,
Hung utilized the lighted sylet for intubation at the
induction of anesthesia with success in 99% of these
patients (68). In a series of 28 trauma patients with
suspected cervical spine injury, the lightwand was employed
for intubation with 100% success as reported by
Weiss (69). In prehospital care, Vollmer reported the use
of the lighted stylet by Emergency Medicine residents in
24 patients with 88% success in less than 45 sec (70).
In Emergency Medicine, lighted stylets have also
proven useful for airway managment in facial trauma,
and appear to facilitate intubation while preserving immobility
of the cervical spine (70,71). The device has
been adapted for nasotracheal intubation as well as orotracheal
use (70). Complications are infrequent with use
of the lighted stylet (63).
Stylets have been modified to include optical viewing
fibers as well as lighting. Such stylets may be used for
routine or difficult tracheal intubation (73–75). These
devices allow direct visualization of structures at the tip
of the endotracheal tube as it is inserted, simplifying
intubation when a poor laryngoscopic grade is encountered,
and facilitating confirmation of tube placement.
Some of the available instruments display the image on
a video screen at the bedside, while others require the
operator to look through an objective lens as the device
is inserted into the airway (73,74). These instruments are
best used in conjunction with a laryngoscope or the hand
of an assistant to elevate the mandible and soft tissues
out of the way for optimum visualization. Limitations
include potential fogging and interference with the view
by secretions, the need to become familiar with viewing
characteristics, and the cost of the devices, which is
considerable.
The intubating fiberoptic stylet has not been subjected
to controlled, comparative studies in the management of
the difficult airway. However, in small series, it has
proven useful for airway management in the OR. In 32
patients undergoing general anesthesia for surgery, 94%
of cases were intubated successfully on the first attempt
and the remainder on the second attempt using this
device (74). Gravenstein compared the fiberoptic stylet
with direct laryngoscopy and with bronchoscopic intubation
in 75 patients under general anesthesia, evaluating
the time required for intubation, the quality of the view
of the glottis, and the frequency of complications (75).
The authors reported a shorter time for intubation using
the fiberoptic stylet than for the bronchoscope, and a
lower rate of postoperative sore throat than direct laryngoscopy,
but also noted that the least favorable laryngoscopic
view occurred with the fiberoptic stylet. When
compared to conventional intubation with direct laryngoscopy
utilizing an Eschman stylet in simulated grade 3
laryngoscopy in a mannequin model, Biro described
100% success using the fiberoptic intubating stylet in
tracheal tube placement by 45 anesthetists in 225 intubations,
whereas there was a 40% rate of tube misplacement
(20% esophageal, 20% endobronchial) utilizing
direct laryngoscopy under these circumstances (76).
Aids to Ventilation
Occasionally, the emergency physician will attempt RSI,
only to find that intubation is impossible due to abnormal
anatomy, pathology, or poor visibility. Much less frequently,
ventilation by mask will fail in the same patient,
despite attempts to optimize it (17). When both of these
conditions are met, desaturation and hypercarbia will
occur within minutes, or possibly seconds, depending on
the degree of preoxygenation, the patient’s body mass,
current oxygen utilization, and associated cardiopulmonary
pathology (34). Cricothyrotomy or transtracheal jet
ventilation should be quickly carried out, but an adjunct
to ventilation may be utilized to temporize while preparations
for the more invasive procedure are made. Aids to
ventilation are placed in either the supraglottic or infraglottic
airway, depending upon the clinical situation.
The laryngeal mask airway (LMA) (LMA of North
America) has been in widespread use by anesthesiologists
in Europe since the 1980s, when it was developed
by Brain (77). It was introduced in the U.S. in the early
1990s, and is utilized worldwide for the conduct of
anesthesia. The device is composed of a semirigid tube
attached to an inflatable “mask” that is placed into the
hypopharynx, and advanced over the larynx. When in-