Difficult airway management in the emergency department.

Clinical
Communications
PII S0736-4679(01)00435-8
DIFFICULT AIRWAY MANAGEMENT IN THE EMERGENCY DEPARTMENT
Steven L. Orebaugh, MD
Department of Anesthesiology, University of Pittsburgh Medical Center, Southside, Pittsburgh, Pennsylvania
Reprint Address: Steven L. Orebaugh, MD, Department of Anesthesiology, UPMC-Southside, 2000 Mary St., Pittsburgh, PA 15228
e Abstract—Most airway management in the emergency
department is straightforward and readily accomplished by
the emergency physician. The exact incidence of difficult
intubations is difficult to discern from available evidence,
but these are probably more frequent in the Emergency
Department than in the operating room, given the urgent
nature of the procedure and the lack of preparation of the
patient population. A variety of adjuncts for airway management
are available to assist in both intubation and ventilation.
The utility of these adjuncts is detailed in this
review, with emphasis on techniques most useful to the
emergency physician. © 2002 Elsevier Science Inc.
e Keywords—airway management; intubation; ventilation
laryngoscopy; airway adjuncts; difficult intubation and
ventilation
INTRODUCTION
Emergency physicians are frequently required to provide
timely, definitive airway management in acutely ill patients.
As the specialty has emerged and then matured
over the last two and a half decades, practitioners of
Emergency Medicine have become increasingly proficient
in this skill, and have modified their approaches to
airway management significantly, relying less and less
on assistance from other medical specialists (1). Residency
training in Emergency Medicine, however, provides
little training in the nonsurgical approach to the
difficult airway (2). Emergency physicians are expected
to emerge from residency with competence in the surgical
management of the airway, but with improved intubation
rates have come reduced opportunity for cricothyrotomy
(3). Because patients presenting with difficult
airways are uncommon but not rare, and because the very
nature of emergency practice may predispose to difficulties
with airway management, it behooves the emergency
physician to become familiar with a range of airwaymanagement
techniques, including direct laryngoscopy
with rapid sequence intubation (RSI), alternatives to
laryngoscopy for intubation, rescue ventilation techniques,
and surgical approaches to the airway. This review
will concentrate upon recognition of the difficult
airway, preparation for managing the difficult airway,
and the various adjuncts available to facilitate intubation
and ventilation in this setting.
Definitions
RECEIVED: 29 December 2000; FINAL SUBMISSION RECEIVED: 2 July 2000;
ACCEPTED: 17 July 2000.
31
The Journal of Emergency Medicine, Vol. 22, No. 1, pp. 31–48, 2002
Copyright © 2002 Elsevier Science Inc.
Printed in the USA. All rights reserved
0736-4679/02 $–see front matter
The term “difficult airway” defies simple definition. It
may be construed to mean difficult laryngoscopy, difficult
mask ventilation, difficult endotracheal tube placement,
or the failure to intubate or ventilate. Some of
these ideas have been expressed quantitatively: difficult
mask ventilation is defined by the American Society of
Anesthesiology as the inability of a trained anesthetist to
maintain the oxygen saturation above 90% by using
face-mask ventilation (when the initial saturation was in
the normal range) whereas difficult intubation is defined

32 S. L. Orebaugh
Figure 1. Grades of laryngeal exposure (reprinted with permission by Blackwell Science, Ltd. (9)).
as an inability to place an endotracheal tube within 10
min or three attempts (4).
Difficult intubation usually corresponds to poor glottic
visualization during direct laryngoscopy, or a highgrade
laryngeal view with no ability to see the vocal
cords or the glottic aperture (Figure 1) (5). Cormack and
Lehane, in a paper that described the likelihood of difficult
intubation in obstetrics, proposed a classification
scheme for views of the laryngeal inlet obtained at laryngoscopy
(5). This four-grade scheme has become the
standard measurement of glottic views, and facilitates
communication between researcher and practitioners as
to the impact of the view obtained on the success of
tracheal tube placement. Grade 1 corresponds to a view
of all or most of the glottis; Grade 2 to a view in which
only the posterior portion of the glottis is visible; Grade
3 to visualization of only the epiglottis; and grade 4 to
inability to see the glottis or epiglottis at all (5). The
authors maintain that Grade 3 and 4 views are rare and
likely to be difficult to manage, whereas grades 1 and 2
are quite common and easily managed by the practicing
anesthesiologist.
Difficulty with glottic exposure at direct laryngoscopy
also can be quantitated by the “Percent of Glottic Opening
(POGO)” score, which corresponds to the proportion
of the opening that can be visualized (6). In addition,
Adnet et al. have more recently proposed an intubation
difficulty scale, which they then validated prospectively
in 626 patients, and which corresponds well to the time
required for intubation and a visual analog scale assessment
of procedural difficulty by intubators (7).
Prediction
Predicting which patients will present challenging or
impossible ventilation, laryngoscopy, or intubation is
troublesome and most assessments lack accuracy. Falsepositive
and false-negative predictions are inevitable.
However, some predictors have proven consistently useful,
and combinations of predictors even more so. Perhaps
the most utilized predictive scheme for airway
assessment in anesthesiology is the Mallampati classification,
which assigns three gradations of increasing difficulty
in visualizing the posterior pharyngeal structures
in order to predict difficult laryngeal exposure (8). The
Samsoon and Young modification breaks this assessment
into four classes, the highest grade divided into those
whose soft palate can be seen and those whose cannot
(Figure 2) (9). These predictive tools evaluate the size of
the tongue, which must be displaced in order to view the
glottis, relative to the oropharynx. In one study, 14 of 15
Figure 2. Samsoon and Young modification of Mallampati classification, evaluating relative size of oropharyngeal structures in
order to predict difficulty in laryngeal exposure during direct laryngoscopy. Higher class number suggests greater difficulty in
glottic exposure (reprinted with permission by Blackwell Science, Ltd. (9)).

Difficult Airway Management 33
patients whose airway assessment fell into the Mallampati
Class 3 were determined to have a poor laryngoscopic
grade at direct laryngoscopy (10).
Many other airway assessment schemes have been
proposed and evaluated, including evaluation of the jaw
size, thyromental distance, and cervical range of motion
(11–14). Each of these has limited sensitivity and specificity,
and most anesthesiologists combine an assessment
of the Mallampati class, mouth opening, cervical
range of motion, and thyromental distance to comprise a
multifactorial approach to predicting difficulty in direct
laryngoscopy. This approach successfully predicts difficulty
in nearly all instances (15,16). A simple “Rule of
Three’s” also can be applied: If one can place three
fingerbreadths between the teeth, between the mandibular
genu and the hyoid bone, and between the thyroid
cartilage and the sternal notch in neutral position, direct
laryngoscopy probably will be successful (15). Recent
evidence suggests that difficult bag-valve-mask (BVM)
ventilation may be more frequent than previously
thought (17). Langeron found that 5% of 1502 patients
were difficult to ventilate by BVM under general anesthesia
(SaO 2 fell below 92% or unable to obtain evidence
of effective ventilation) but this situation was anticipated
in less than one fifth of these cases. Body mass index,
advancing age, presence of a beard, lack of teeth, and a
history of snoring all predicted difficult ventilation by
BVM.
Unfortunately, these assessment tools have been derived
from studies in which cooperative, composed patients
are examined by anesthesiologists on preoperative
rounds rather than by emergency physicians evaluating
patients in extremis. The utility of these tools in the
Emergency Department (ED) setting has not been demonstrated.
Nevertheless, an appreciation of mouth opening,
cervical mobility, thyromental distance, and tongue
size can be rapidly gained and may help the emergency
physician avoid a disastrous sequence of events when
difficulty is likely.
Incidence
Much had been done to document the occurrence of
difficult airways in the perioperative setting. Grade 3
laryngoscopy, requiring multiple attempts at intubation,
occurs in 1–4% among all types of patients, but was
estimated to occur in only 1 of 2000 obstetric patients,
who have relatively normal necks and cervical mobility
(5,11,18,19). Inability to intubate due to severe Grade 3
or Grade 4 laryngoscopic views is present in only 0.05–
0.35% of operating room (OR) cases, but again appears
to be more rare among those with normal cervical mobility
(5,9,18,20). Difficult mask ventilation occurs 5%
of the time, as outlined above (17). Fortunately, inability
to ventilate combined with inability to intubate is very rare
in the OR, comprising less than 2 in 10,000 cases (13,21).
Mild difficulty with intubation requiring a change of blades
or operators is fairly common, reportedly occurring in
1–18% of intubations in the OR (21–23).
Management of the difficult airway in the ED has not
been as well studied as that in the OR. Indeed, it is
necessary to extrapolate from descriptive studies of airway
management in the ED, in which significant portions
of the population under study are excluded from the
investigation for various reasons. Sakles et al., describe
610 patients undergoing intubation in an urban ED over
1 year, 84% of these were rapid sequence intubations
(RSI) with a 99% success rate, and 1% required cricothyrotomy
(25). Five percent of patients initially received
an esophageal intubation; we can surmise, then, that
6% of these patients had a difficult airway. Overall, 5%
required three or more attempts at direct laryngoscopy,
and these could perhaps be added to the other 6% (if we
presume no overlap between these and the patients having
an esophageal tube), and thus some difficulty in
intubation would range between 6% and 11%. However,
some 16% of patients were deemed unfit for RSI, and the
reasons for this are not apparent in all cases.
In the study of Tayal et al., the proportion of difficult
airways among patients intubated is also somewhat obscure
(26). Thirty percent of patients who were intubated
were not included in the analysis because they did not
meet the investigators’ requirement for eligibility for
RSI. Again, 1% required cricothyrotomy. Thus, the actual
incidence of difficult airways lies somewhere between
the extremes of 1% and 30%. Even if we choose the
lower figure, difficult airways in the ED population will not
be considered rare, and they are probably much more
commonly encountered in this setting than in the OR.
More recently, a multicenter study of ED airway
management has been conducted (27). This investigation,
a prospective, observational study of almost 6300
cases, comprises the most comprehensive data regarding
emergency physician practices in management of the
airway. In a query of the National Emergency Airway
Registry data, Li reported esophageal intubation in 4%
of cases, though only a small fraction of these were not
immediately recognized (28). Rapid sequence intubation
was the predominant method used to provide airways in
this population, with over 98% success in over 4400
patients. Other methods included oral intubation with
sedation only, oral intubation with no medications, and
blind nasal intubation, all of which were significantly
less successful techniques than RSI in securing the airway.
Thus, RSI appears to be the most frequently used
and most successful means of intubating the trachea in
Emergency Medicine.

34 S. L. Orebaugh
As noted above, the very nature of emergency practice
may contribute to difficulties in airway management
not encountered in more elective settings. The inability
to ask the patient if he or she has encountered prior
airway problems (including surgery or adverse anesthesia
occurrences) due to confusion, extremis, or obtundation
is common. Further, having the patient adopt a
sitting position while examining the pharynx, thyromental
distance, and cervical range of motion is frequently
impossible due to the acute nature of the patient’s illness
or the impracticality of adopting such positions. The
presumption of a “full stomach” in all patients intubated
emergently dictates the use of the RSI technique. The
imposition of cricoid pressure and laryngoscopy at the
earliest possible moment place increased demands upon
the physician preparing to intubate the patient (29). The
trauma patient places even more obstacles to intubation
in the path of the emergency physician. Facial distortion,
secretions, swelling, mandibular injury, and potential
cervical spine injury all combine to make these patients
among the most challenging airway-management problems
(30). Cervical collars and in-line immobilization
impact glottic exposure adversely, and up to 20% of
these patients may have a Grade 3 or Grade 4 laryngoscopic
view (31).
In summary, the difficult airway can be defined in
different ways, and its exact incidence in the ED is not
clearly delineated. Poor laryngoscopic grade is apparently
more common in the ED population than in patients
presenting for elective surgery, given the frequency of
multiple attempts at intubation and esophageal intubation
cited in the studies above. Nevertheless, failure to secure
the airway by nonsurgical means is quite infrequent in
the ED, on the order of 1% of cases.
Approach to the Recognized Difficult Airway
In many cases, difficulty with glottic exposure may be
predicted from even a cursory examination of the patient.
In others, it is only apparent after a hypnotic and relaxant
have been administered, during attempted direct laryngoscopy.
This situation may quickly lead to multiple
attempts to secure the airway, supraglottic swelling and
bleeding, deterioration of ventilation, and hypoxemia
with potential morbidity (32–34). Because of the potential
for injury and mortality when airway disasters occur,
the American Society of Anesthesiology (ASA) developed
the ASA Difficult Airway Algorithm, which was
introduced to the anesthesia community in 1993 (Figure
3) (4). Since its implementation in the United States,
morbidity, mortality, and claims related to airway mismanagement
in the OR have fallen significantly (35).
Unfortunately, the ASA algorithm has a number of
characteristics that prevent direct application to the practice
of Emergency Medicine, because of dissimilarities in
airway management in the OR and the ED (Table 1). All
airway management in the ED is urgent or emergent,
often depriving the physician of the time necessary to
evaluate the patient and plan this lifesaving intervention.
Furthermore, each patient is presumed to have a full
stomach in the ED, and therefore must undergo RSI, with
its attendant time pressure and requirement for cricoid
pressure, which may distort the view of the glottis. As
noted above, the trauma patient presents unusual demands
for airway management, including potential facial,
cervical, and airway injury, and cervical immobilization
during intubation. In the ED, intubation is
conducted on the basis of patient need, whether for
airway patency and protection or acute respiratory failure,
whereas in the OR, patients are usually intubated to
guarantee airway protection and ventilation during a
reversible, pharmacologically maintained unconscious
state. This leads to a strong emphasis in the ASA algorithm
on preserving the option of reemergence from
anesthesia to resume spontaneous ventilation if difficulty
is encountered (4). This approach is often impossible in
Emergency Medicine because the patients’ pathology
dictates that a definitive airway be obtained by whatever
means possible. Finally, the orientation toward the surgical
airway is different among anesthesiologists and
emergency physicians, as the latter generally have more
training in provision of cricothyrotomy (36).
Can emergency physicians benefit from an algorithm
similar to that of the ASA for management of the difficult
airway? Perhaps. Walls, in his text on airway management
in the ED, recommends the use of a “Universal
Algorithm” for emergent provision of the airway, along
with several more specific algorithms for consideration
in specific circumstances (“difficult airway algorithm,”
“crash airway algorithm,” “failed airway algorithm”)
(37). Although these guidelines lack prospective validation,
they represent a more appropriate application of
principles and constraints to airway management in the
ED setting.
Adjuncts for Difficult Airways
Aside from the emergency surgical airway achieved by
open or percutaneous cricothyrotomy, which has been
effectively used by emergency physicians for difficult
airway management for more than two decades, there is
a broad array of adjuncts to assist with ventilation or
intubation (34). When the patient can be ventilated by
BVM, but not intubated, these adjuncts may be employed
to facilitate placement of an endotracheal tube.
Some of these techniques are minor modifications of

Difficult Airway Management 35
Figure 3. American Society of Anesthesiology Difficult Airway Management Guideline.
direct laryngoscopy. There are noninvasive and invasive
techniques, blind techniques, and those involving direct
visualization. Some are effective for unforgiving anatomy,
but less so for glottic or supraglottic pathology. A
discussion of the various adjuncts, procedures, and devices
follows, with particular emphasis on those most
appropriate for the emergency practitioner. It is of paramount
importance, however, that when ventilation by
BVM fails after inability to intubate the trachea, one
makes immediate preparations for provision of a surgical
airway or transtracheal jet ventilation, because hypoxemia
will rapidly occur (34,37,38).
Blades for Direct Laryngoscopy
A large variety of retraction blades for laryngoscopy are
available. Although many variations of the curved and
straight blade exist, the Miller and MacIntosh blades,
introduced about 50 years ago, remain pre-eminent

36 S. L. Orebaugh
Table 1. Comparison of Airway Management in the ED and the OR
Aspects of Airway
Management Emergency Medicine Anesthesiology
Goals Obtain definitive airway Assure patent airway and ventilation while patient is unconscious
Patient characteristics Always urgent or emergent Usually elective situation
Frequent C-spine precautions Infrequent C-spine precautions
Respiratory failure common Respiratory failure rare
All presumed full stomach Usually NPO
Usual preparatory time Seconds to minutes Hours to days
Alternatives for failed airway Must progress to definitive airway Emphasis on awakening patient to secure awake airway,
or cancel
(39,40). Conventionally, the straight blade is inserted
beneath the epiglottis and used to directly expose the
glottis, whereas the curved blade fits into the vallecula,
pulling on the hypoepiglottic ligament as it is lifted, to
flip the epiglottis out of the way, allowing the operator to
see the exposed glottis. Certain situations, such as a very
“deep” glottis, or protuberant “buck” teeth, seem to favor
use of the straight blade (41). Some variants of the Miller
blade, such as the Phillips blade, have a higher vertical
profile, answering one of the deficiencies of this type of
blade: excellent visualization but inadequate space for
endotracheal tube insertion (42). Other varieties of laryngoscope
blade that may prove useful in unusual situations
include angled blades, blades with no vertical
flange, and blades with mirrors (Table 2) (39,40,42–48).
Most of these are rarely used in clinical practice.
Of recent interest is a blade that can incorporate a
prism for refraction, to improve the operator’s view of
the larynx, and that also may be used without the prism
for conventional laryngoscopy (45). Deemed the Belscope,
it is a straight blade with a 45° angulation at its
midpoint, and is available in three sizes. This blade has
been studied extensively by its originator, for whom it is
named, and applied successfully to normal anatomy and
difficult airways (49). The McCoy laryngoscope blade is
Table 2. Selected Retraction Blades
an articulating blade that allows one to lift the distal tip
of the blade to improve the view of the glottis if the
epiglottis impedes visibility (47). This blade has been
compared in several studies to the standard MacIntosh
blade, and can improve the laryngoscopic grade significantly,
but does not do so consistently (50,51). A doubleangled
laryngoscope blade has been developed that combines
features of both the straight and curved
laryngoscope blade (46). Its utility remains unproven.
Lastly, the “Improved View MacIntosh” blade allows an
enhanced view of the larynx, due to a concavity in the
flat portion of the blade (48).
Aids to Direct Laryngoscopy
Aids to direct laryngoscopy include prisms, mirrors, and
bougies, or Eschmann stylets. Initial use of the optical
prism dates to the early 20th century, but little development
of the technique occurred until the late 1960s, when
Huffman described a prism made from Plexiglas for
attachment to the vertical flange of the standard MacIntosh
blade, which provides 20° of refraction (52). This
helped the laryngoscopist gain a view of the glottis when
a grade 3 or grade 4 view was present, facilitating intu-
Blade Characteristics Uses/Advantages References
Miller Straight, low vertical profile Normal airways, long epiglottis
Prominent incisors, “deep” glottis
39
MacIntosh Curved blade Normal airways 40
Phillips Straight, higher vertical profile More room for ETT* placement than Miller
blade offers
42
Bizzarri-Giuffrida Flangeless version of MacIntosh blade For small mouth or prominent teeth 44
Siker Incorporates mirror into blade Better visualization of anterior-situated
larynx
43
Double-angle Blade has 20° and 30° angle bends Better exposure of anterior larynx 46
Belscope Angulated, and has optional prism Can use for routine airway, or add prism 45
McCoy Articulated, levering version of
MacIntosh blade
if poor visualization
Moves fulcrum to lower pharynx to
minimize dental trauma in lifting the
epiglottis
Improved-view MacIntosh Concavity in blade Provides better view of anterior glottis 48
* ETT, endotracheal tube
47

Difficult Airway Management 37
Figure 4. Gum elastic bougie, employed to facilitate intubation
of a poorly visualized glottic aperture (reprinted with
permission by Mosby-Year Book, Inc. (55)).
bation. These prisms are available today at low cost and
are easy to use, although fogging can be troublesome
unless the device is warmed before use, and the prism
reduces the room for manipulation of the endotrachael
tube (ETT).
Mirrors have been used to facilitate ETT placement
when the glottis is difficult to visualize. These include
blades with an integral mirror that provide an inverted
view of the glottis, such as the Siker blade (43). The
Neustein blade involves a mirrored attachment to the
MacIntosh balde that includes a guide channel for a
stylet, over which the ETT is passed after the blade is
removed (53). Both of these devices result in an inverted
image as viewed by the laryngoscopist, with some degree
of initial unfamiliarity making their use cumbersome.
Neither is frequently used in clinical practice.
At times, it is beneficial to insert a guiding catheter, or
bougie, into the glottis, then slide an ETT over it. The
device thus provides a means to intubate blindly during
direct laryngoscopy, when the glottis is not well visualized
(54–56). The malleable Eschmann stylet, with its
stiff, angulated end, lends itself to this task because it is
small enough to be maneuverable in the pharynx, where
it is used to “probe” for the glottic opening, and its end
is firm enough to rattle against the tracheal rings as it is
placed in the trachea, providing the intubator a sense of
correct placement (Figure 4). It is frequently used for
difficult airway management in the ED in the U.K. (57).
Little comparative data exist to support the use of the
Eschmann stylet in preference to other means of managing
the airway in the ED, but numerous case reports and
case series attest to its value in difficult intubation in the
OR, and more recently in emergency practice (54–56).
Interest in this low-cost, simple device appears to be
increasing among emergency physicians. Moscati reported
the efficacy of this device in three cases in the ED
in which the glottic inlet could not be visualized and
intubation by direct laryngoscopy had repeatedly failed
(58).
The recently introduced Frova intubating stylet (Cook
Critical Care, Bloomington, IN, USA) similarly allows
blind intubation and passage of an ETT over the device,
but is hollow and has an adaptor allowing jet ventilation
or oxygen insufflation during the intubation. Other devices
also can be used as stylets, including airwayexchange
catheters, which permit attachment to an anesthetic
circuit, resuscitation bag, or jet ventilation system.
Use of a laryngotracheal anesthesia kit, with its plastic
stylet, likewise has been described for this purpose (59).
Blind Nasotracheal Intubation
Blind nasotracheal intubation (BNTI) remains a viable
option for intubation in the ED, in routine intubation and
difficult airway management. In the National Emergency
Airway Registry study, this method was utilized in about
5% of all intubations, with a success rate of 85.7% within
three attempts. In Dronen’s comparison of BNTI to direct
laryngoscopy for intubation, the rate of successful
intubation was significantly lower at 68%, in comparison
to direct laryngoscopy with the use of succinylcholine
for muscle relaxation, with which there were no failures
(60). In addition, complication rates, mostly nasal bleeding
and emesis, were much higher with BNTI. When
paramedics utilized BNTI in 219 intubations, the rate of
appropriate ETT placement improved from 58% to 72%
when a directional tip control tube was utilized (61).
Lighted and Optical Stylets
Stylets have evolved in function, cost, and complexity. In
the late 1950s, Yamamura described transillumination
for use in nasotracheal intubation (62). Use of the lighted
stylet, or lightwand, has been well described since then,
as a blind technique in the face of difficult intubation, as
well as for routine airway management (63–65). Early
commercial lightwands suffered from poor illumination
and misdirection of the light, so that a darkened room
was necessary to see the halo produced in the glottic area
during insertion into the airway. The lamp switch was

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-

Difficult Airway Management 39
flated, this mask provides a seal around the glottic aperture
(78). The LMA is available as a reusable device as
well as a disposable one, in sizes ranging from those for
neonates to those for large adults.
LMA insertion requires skill, practice, and familiarity
with the conformation of the device (77). However, it
may be inserted without muscle relaxants, and lends
itself to emergency ventilation, because it provides a
greater degree of airway patency than does a face mask.
The LMA has been utilized as an emergency ventilation
adjunct in a variety of circumstances (78–80). It also can
be used effectively as a “bridge” to fiberoptic intubation,
because an ETT of size 6.0 or smaller may be passed
through the LMA and over the fiberscope, while the
lumen of the device effectively guides the bronchoscopist
to the laryngeal opening (79–81). Limitations include
a seal that is unreliable at high peak inspiratory
airway pressures: about one-third of the tidal volume is
lost during positive pressure ventilation with the LMA
when the peak inspiratory pressure reaches 30 cm of
H 2O, and the effectiveness of ventilation deteriorates
further as peak airway pressures increase (82). Failure to
protect the patient against aspiration of gastric contents is
another concern. Mucosal trauma may occur on insertion
of the LMA, and placement is occasionally difficult,
particularly for the unfamiliar operator (77–80). A new
version of the LMA, which soon will be introduced in the
U.S., will have a port for gastric emptying (83).
The LMA has proven useful both as an alternative to
BVM in cardiopulmonary arrest and as a rescue device in
difficult airway management. Among intensive care unit
nurses, Martin found that the LMA proved easier to use,
and provided a better tidal volume with less likelihood of
airway obstruction than BVM ventilation with or without
an oral airway (84). When untrained volunteers were
assessed for the ability to ventilate patients under general
anesthesia, Alexander described marked improvement in
success of ventilation and oxygenation when the LMA
was used, compared to BVM ventilation (85). He reported
a 43% rate of failure to ventilate effectively with
the latter device, whereas the LMA was successful in all
but 13% of cases. Likewise, Smith found that anesthetists
were better able to maintain oxygen saturation and a
patent airway in 64 patients under general anesthesia
randomly assigned to ventilation using the LMA as opposed
to a face mask (86).
In an evaluation of LMA utility in prehospital care,
Pennant described placement of LMA by paramedics in
100% of cases in less than 40 sec, whereas endotracheal
tube placement required more than twice that long and
resulted in 31% misplacement (87). Davies described
placement of an ETT or LMA in a mannequin by paramedics
with little training: 94% of LMA insertions were
successful, compared to only 51% of ETT insertions
(88).
Little comparative clinical data exist to support use of
the LMA in the ED. It has been well established during
difficult airway management and rescue ventilation in
the OR (79–81). Experienced practitioners can usually
insert the LMA within 20 s, with a success rate of
ventilation of 98% (89). Parnet described the use of the
device as the adjunct of first choice by academic anesthesiologists
facing difficult-intubation or difficult-ventilation
situations in 17 cases over 2 years, with a 94%
success rate, whereas other modalities were significantly
less successful (90). Only one case report has been
published to date describing failure of the LMA in a
cannot-intubate/cannot-ventilate situation (91). Thus, the
considerable experience with the LMA in unexpected
difficult airway management in the OR may substantiate
an attempt at its use when considering a surgical airway
for the failed airway in the ED because it can be inserted
so quickly and with high expectation of success (92). Its
use may allow the conduct of an orderly, composed
surgical airway, as opposed to a very hastened procedure
in a desaturating patient.
In a meta-analysis of the literature, Brimacombe
found that the incidence of reported aspiration of gastric
contents during use of the LMA is exceedingly low, on
the order of 2/10,000 cases, a rate similar to that encountered
with general anesthesia with the use of a cuffed
endotracheal tube (93). A new model of the LMA, recently
introduced, incorporates a dorsal cuff, a drainage
tube for insertion of a gastric tube, a double cuff configuration,
and an introducer device. The Proseal LMA
(Laryngeal Mask Company, Henley-on-Thames, UK)
has been evaluated in a randomized, crossover study in
anesthetized patients, in which it was compared to the
LMA (94). The authors reported 100% success with
both devices, but noted that the LMA was judged
easier to insert, and could be placed more quickly,
with higher success on the first attempt. A gastric tube
was placed successfully through the Proseal LMA in
all cases.
The intubating laryngeal mask airway (ILMA) (Fastrach,
LMA of North America, Long Beach, CA, USA)
is a derivation of the LMA that facilitates endotracheal
intubation after placement of a laryngeal mask and which
has some features distinct from the conventional one.
The laryngeal mask is attached to a rigid stainless-steel
airway tube, which has a larger internal diameter than the
standard adult LMAs, and which has a handle to ease
placement. This tube admits a flexible, reinforced endotracheal
tube specially manufactured for this laryngeal
mask. The mask and tracheal tubes come in three sizes
for adults.
The ILMA has received significant study in anesthe-

40 S. L. Orebaugh
siology, but little in the ED. Nonetheless, the device has
promise for managing the difficult airway in either setting.
The enormous popularity of the LMA in Europe and
other areas around the world has led to ready acceptance
of the ILMA. In Australia, Agro described its use in 110
patients slated for general anesthesia, with 95% success
in establishing ventilation through the laryngeal mask
(95). However, the authors encountered resistance to
ETT insertion, requiring some form of adjustment of the
apparatus, in 60% of patients, with an intubation time
averaging 79 s. In a multicenter study from the U.K.,
Baskett assessed the efficacy of the ILMA in intubation
of 500 patients undergoing general anesthesia, again with
95% success in ventilation through the mask portion of
the device (96). The authors had 80% success on the
first intubation attempts, with 4% of patients requiring
three attempts and a failure rate of 4%. In another report
from Britain, Brain used the ILMA to attempt intubation
of 150 patients undergoing general anesthesia, with success
in ventilating all of the patients with the laryngeal
mask (97). In half of patients, resistance to ETT placement
was encountered, requiring one of several adjusting
maneuvers before intubation was successful. The study
included 13 patients with “potential or known” airway
difficulty, all of whom were intubated successfully. A
slate of four different adjusting maneuvers is described,
based upon the level at which resistance to ETT advancement
is encountered (97). In 38 patients with known
difficult airways, based on historical failure of laryngoscopy
or physical examination features predicting difficulty,
Joo assessed the utility of the ILMA compared to
awake intubation with the fiberoptic bronchoscope
(FOB) (98). All awake FOB attempts were successful,
but only half of patients could be intubated blindly with
the ILMA. The other half required the use of a bronchoscope,
and 10% required involvement of a second operator
to place the ETT.
Less data exist that evaluate the ILMA for airway
management in the ED. Asai, simulating trauma resuscitation
with manual in-line immobilization of the cervical
spine in anesthetized patients, evaluated the ILMA
for intubation in 40 cases (99). The ILMA was used in
conjunction with FOB to ensure correct placement, and
this tandem was compared to direct laryngoscopy with
use of an Eschmann stylet. The authors reported 85%
success of intubation with the ILMA under these circumstances,
but less than half of the patients in the laryngoscopy
group were successfully intubated with these restrictions.
Rosenblatt reported three cases of successful
intubation with the ILMA in patients in whom direct
laryngoscopy had failed in the ED (100). The authors
commented of the ILMA that “proficiency in its use
requires practice under controlled conditions,” and suggested
that “the emergency physician seek out elective
practice” before assuming it can be used successfully
under emergent circumstances.
Some authors have attempted to study the utility of
the ILMA in the hands of unskilled or inexperienced
operators, as might occur among paramedics or nurses
during resuscitation attempts. When use of the ILMA
was evaluated among untrained airway operators, and
compared with their ability to perform direct laryngoscopy
and intubation in a random cross-over trial involving
anesthetized patients, Avidan found that the participants
performed poorly with each device, with a 35–40%
overall success in intubation (101). In a cadaver study,
medical students were assessed in their ability to ventilate
with the ILMA or the LMA (102). The authors found
that the students could more effectively ventilate with the
ILMA than the LMA (92% vs. 76%, respectively). However,
they could intubate successfully with the ILMA in
only 67% of cases. Thus, the ILMA may be preferred to
the LMA for emergency ventilation in the ED, given its
higher success rate and its potential for converting ventilation
to intubation of the trachea. However, intubation
through the device requires practice and familiarity, and
is not met with a high degree of success in the neophyte.
Furthermore, the device is much more expensive than the
disposable LMA.
The esophageal-tracheal combitube (ETC) (Sheridan
Catheter Corporation, Argyle, NY, USA) is another airway
rescue device that facilitates ventilation by bringing
the source of oxygen closer to the glottis than does the
standard face mask. This dual lumen tube is generally
inserted blindly into the pharynx, and is then advanced
into either the esophagus (95–99% of cases) or the trachea
(103). Ventilation through the color-coded, numbered
tubes is then employed to determine the position of
the tube. The ETC enjoys more popularity in the emergency
setting than the LMA in the U.S. (104,105).
The ETC has been used effectively in routine and
emergent airway management in anesthesia, in prehospital
airway management, in cardiopulmonary resuscitation,
and in the ED management of difficult airways
(103,105–107). The ETC has been shown to be a reliable
device for prolonged mechanical ventilation in ICU patients
(108). During cardiac arrest, this device has proven
efficacious to provide adequate ventilation with shorter
intubation times than standard direct laryngoscopy (109).
Critical care nurses were able to ventilate with the ETC
during resuscitations as effectively as physicians intubating
these patients (107). Among prehospital providers
not trained to intubate the trachea, a modified, randomized,
cross-over study design was used to compare the
ease of insertion and adequacy of ventilation among the
ETC, LMA, and pharyngeal tracheal lumen airway
(105). Successful insertion and ventilation occurred more

Difficult Airway Management 41
frequently with the ETC than with the other two devices,
and was preferred by this group of providers.
Indications for use of the ETC include predicted difficult
airway and inability to visualize the glottis during
direct laryngoscopy (103,104,106). This adjunct may be
inserted with the use of a laryngoscope as well as blindly.
Advantages of the ETC include the potential for reduced
risk of aspiration when compared to a face mask or the
LMA, preservation of cervical spine immobilization, and
the ability to insert the device when a laryngoscope is not
available (103–106). The relatively large size of the ETC
and its inherent stiffness predispose to esophageal dilatation,
and lacerations of the piriform sinus and esophagus
have been reported (110,111).
Transtracheal Jet Ventilation
At times, the ETC and LMA are rendered ineffectual by
supraglottic or glottic pathology, such as swelling, abscess,
tumor or foreign body, or by unfavorable anatomy
that precludes their placement, such as limited mouth
opening. Under such circumstances, an approach to
emergent ventilation that utilizes an infraglottic, percutaneous
route is an alternative. Transtracheal “jet” ventilation
(TTJV) requires the placement of a large-bore
i.v. or other catheter through the cricothyroid membrane,
or even directly into the trachea (12,113). This is connected,
preferably by a tight-fitting luer-lock connection,
to a high-pressure oxygen source, which is used to oxygenate
and ventilate the patient (114,115). The catheter
also may be attached to a resuscitation bag via the
connector of a size 3 ETT or to wall oxygen from a
regulator at its highest flow, utilizing a hole cut in the
tubing to control flow of oxygen by periodic occlusion
with the thumb or finger (116,117). These arrangements
do not provide ventilation as effectively as does a high
pressure (50 PSI) oxygen source, which may be delivered
either by an oxygen tank with a “step down” regulator
or directly by the hospital’s wall oxygen system
(112,118). A variety of components can be assembled
piecemeal to create such a system, but commercially
available systems are more reliable and are reasonably
priced (112,119).
When oxygen at high pressure (20–50 PSI) and high
flow (0.5–1.0 L/sec) is delivered by TTJV, air may be
entrained at the catheter tip, augmenting the tidal volume
and increasing the risk of barotrauma. Given the low
rates and high pressures involved, adequate tidal volume
for an adult usually can be delivered in 0.5–1 sec. Utilizing
a lung model with a set compliance of 50 mL/cm
H 20, a 1-sec inspiratory time and a 50 PSI oxygen
source, tidal volumes generated vary from about 600 mL
with an 18-gauge i.v. catheter to over 1200 mL with a
14-gauge catheter (112).
TTJV was demonstrated to be successful in providing
adequate ventilation in cardiac arrest patients as early as
1972, when Jacobs described its use in 40 cases (116).
While utilizing a high-pressure oxygen source, the author
was able to maintain an average pO 2 of 300 mm Hg, and
a pCO 2 of 22 mm Hg with peak airway pressures of
15–25 cm H 2O. Smith in 1975 described the use of TTJV
in 80 patients who underwent airway surgery under anesthesia
(120). Fifty-two of these cases involved elective
use of the technique, while 28 of the patients were
managed while in respiratory distress. Provided that adequate
pressures are utilized to provide necessary flow
rates, numerous investigators have demonstrated that
normocarbia can be maintained while ventilating patients
with this technique (115,116). Most of the patients described
in these investigations were under general anesthesia,
in contrast to patients in acute respiratory failure
who are frequently encountered in the ED. TTJV also has
been useful in high-grade upper airway obstruction, as in
the case of a patient with a large carcinoma at the base of
the tongue who sustained a respiratory arrest (120).
TTJV has been used effectively as a ventilation strategy
in cannot-intubate and cannot-ventilate (“failed airway”)
situations (112,118,119). The technique has also proven
useful in pediatric airway emergencies (122).
When TTJV is utilized, ample time must be allowed
for the passive recoil of the lungs to force exhalation of
the insufflated gas (2–3 sec), or “stacking” of breaths,
and barotrauma may result. Pneumothorax, pneumomediastinum,
and subcutaneous (s.c.) air have all occurred
as a result of TTJV (120,123). Contraindicatons to TTJV
include distorted anatomy that would make placement of
the catheter difficult or impossible, bleeding diathesis,
and complete airway obstruction (112). Adverse effects
include barotrauma, as described above, bleeding at the
site of insertion, and loss of position of the catheter if it
is not held firmly during ventilation (115,118,119).
Retrograde Intubation
Retrograde intubation (RI) was first reported in 1960
(124). This invasive technique allows for blind placement
of an endotracheal tube over a guidewire or catheter
that is inserted percutaneously at the level of the
cricothyroid membrane or cricotracheal ligament and
directed “retrograde” through the pharynx to the mouth
or nose. The procedure was originally described with use
of a red-rubber catheter introduced through a tracheostomy,
and has evolved to include the use of a guidewire
placed percutaneously through the lumen or Murphy Eye
of an endotracheal tube (Figure 5) (125,126). Because an

42 S. L. Orebaugh
Figure 5. Retrograde intubation, comparing the technique of
guidewire-through-lumen of ETT (A) to the technique of
guidewire-through-Murphy eye of ETT (B). Use of the Murphy
eye permits further advancement of the endotracheal
tube into the airway before wire is removed (reprinted with
permission by Mosby-Year Book (35)).
ETT has the potential to move laterally about the wire,
and impact on the aryepiglottic fold or arytenoid cartilages,
the technique frequently incorporates a guide catheter
placed over the wire before the ETT is inserted
(127). Available commercial kits frequently include this
catheter as well.
The technique of retrograde intubation has been used
effectively in the traumatized patient as the presence of
blood or secretions in the pharynx does not detract from
successful intubation via this route (125,128). Retrograde
intubation also has been useful in difficult airway
management in both anesthesiology and Emergency
Medicine (125,129,130). However, this technique has
not been widely applied in Emergency Medicine. Data
regarding its application are limited to case reports and
case series. RI has been described anecdotally in a number
of difficult airway situations, including management
of patients with large oral cancers, spinal cord injury,
oral infections, pharyngeal edema, laryngeal carcinomas,
and airway anomalies (126). Barriot described its use by
emergency physicians in the field, where it was employed
successfully in 13 patients with severe maxillofacial
trauma who could not be intubated by direct laryngoscopy
in the prehospital setting, and in another six
patients in whom the technique was used electively
(128). In the hands of those who use the technique
frequently, RI appears to have a high success rate. Of 383
applications described in the literature by 1996, the technique
was effective in 98.5% of cases (126).
However, preparation and administration of retrograde
intubation usually requires over 2 min to complete,
and sometimes considerably longer (126,128). This
means of managing the difficult airway may therefore be
useful when a patient presents with an obvious or suspected
difficult airway, yet has relatively well-preserved
oxygenation and ventilation (as in head or facial trauma).
RI also could be employed when RSI fails, but mask
ventilation is still possible, allowing time to complete the
procedure.
RI is a reasonably safe procedure. Adverse effects
include bleeding and, rarely, hematoma formation
(99–101). Subcutaneous emphysema or pneumomediastinum
may occur but these complications are usually
transient and self-limited (97,102,103). Bleeding diathesis
is a relative contraindication to the technique, as
are distorted neck anatomy and laryngeal injury
(93,104,105).
Variations on the technique of RI include the use of an
epidural catheter instead of a guide wire, and its use in
combination with fiberoptic bronchoscopy (136,138,139).
The guide wire may be placed through the suction channel
of the fiberscope, leading the endoscopist directly to
the laryngeal opening despite secretions or unfavorable
anatomy. The wire is then removed and the intubation
carried out with direct visualization through the fiberscope.
Fiberoptic Bronchoscopic Intubation
Introduced in the 1960s, FOBs are available in a variety
of sizes, depending upon their use, and are usually 55 or
60 cm in length (140). Instruments used solely for intubation
tend to be smaller in diameter (1.8–4.0 mm) than
those used for diagnosis and therapy of pulmonary disease,
which feature a larger working channel to admit
biopsy forceps and other instruments. The fiberscope
consists of a universal cord, which carries light in fiberoptic
bundles from the light source; a handle containing
an eyepiece, control lever for bending the distal tip of the
scope, suction button and access port to the working
channel; and an insertion cord that contains light bundles
and the image transmission bundle, along with the tip
control wires to allow bending of the tip forward or
backward (141).
Awake intubation with a fiberscope requires ample
time and preparation of the patient. Even in emergent
circumstances, bronchoscopy requires 5–6 min to perform,
and, ideally, with such preparatory measures as

Difficult Airway Management 43
patient sedation, topical and regional anesthesia of the
airway, and administration of an anticholinergic preparation
to dry secretions, 15–20 min is required (130,140).
While controlled studies or comparisons of efficacy
are few, case reports and series abound in the anesthesia
literature of the utility of FOB in management of the
difficult airway (142–148). The effectiveness of FOB for
intubation of the patient with a cervical spine injury is
well established (143,146,148). The intubating bronchoscope
plays a very important role in awake intubation of
the patient with a suspected or known difficult airway
(130). Under these circumstances, the success rate of the
procedure is almost 99%. The simultaneous use of direct
laryngoscopy with FOB may improve the success rate of
the technique by displacing soft tissues that can impede
the fiberscopic view of the glottis (149).
The nasotracheal approach to the airway with FOB is
often simpler than the oral approach because the instrument
is aimed directly at the glottis as it emerges from
the nasopharynx into the hypopharynx (140). Intubation
over the bronchoscope can be successfully performed
through an LMA and around the ETC (130,150). There
are many advantages to the technique, including applicability
to all age groups, excellent airway visualization,
ability to insufflate oxygen during the procedure, high
success rate, and immediate confirmation of ETT placement
(146).
There are significant limitations to bronchoscopic intubation.
In the presence of uncontrolled secretions, mucus,
or bleeding in the airway, visibility is difficult or
impossible. Suction through these instruments is relatively
ineffective, but by attaching an oxygen source to
the suction channel of the instrument, oxygen insufflation
may be used to blow offending matter away from the
lens to improve visibility. Furthermore, the natural compression
of soft tissues of the oropharynx and hypopharynx
in the supine, anesthetized patient can make the
approach to the airway difficult due to physical obstruction
and poor visibility. This is a greater problem in oral
intubation than nasal intubation. Effective means to address
this concern include use of a specialized oral airway
such as the Ovassapian airway or Williams airway,
a jaw thrust by an assistant, or direct laryngoscopy provided
by an assistant (130,140,141). Finally, advancement
of the endotracheal tube over the FOB is difficult in
up to 25% of cases, as the bevel of the tube may catch on
the arytenoid cartilages or aryepiglottic folds. Withdrawing
the endotracheal tube, and rotating it 90° in either
direction usually solves this problem, but about 10% of
the time one cannot advance the tube, requiring a change
to a smaller tube or a different approach to the airway
(140). Barriers to facility include an initial training period,
a relatively slow learning curve, and failure to
retain skills when the procedure is infrequently utilized
(140).
In the ED, little systematic study has accrued on the
utility and efficacy of FOB in airway management.
Delaney reported a series of 57 intubations carried out by
two emergency physicians trained on a mannequin in the
use of a 50-cm fiberoptic scope (151). The cases were
selected for the skill level of the physicians (more than
half were overdose patients). The authors reported a 13%
failure rate, and 22% of the patients had significant
bleeding with the nasotracheal approach. In another
study of fiberoptic intubation in the ED, the authors
reported that only 75% of 39 patients were successfully
intubated by use of the fiberscope, whereas 95% of a
comparable group of patients were managed successfully
with direct laryngoscopy (152). Levitan, in a study of ED
practices at U.S. teaching hospitals, found that the FOB
was seldom employed as a means of management of the
difficult airway (2).
Rigid Fiberoptic Laryngoscopes
Several rigid fiberoptic laryngoscopes are available. The
oldest, and most familiar, is the Bullard laryngoscope
(Circon, ACMI, Stamford, CT, USA). The operator inserts
the scope into the hypopharynx, and under indirect
vision through the eyepiece, advances the blade into
position cephalad to the glottis. The endotracheal tube
can then be pushed forward off the stylet, into the glottis
during visualization. The Bullard laryngoscope is indicated
for airway management when the glottis is difficult
to visualize due to unfavorable anatomy, and when preservation
of cervical spine immobilization is essential. It
also may be used for routine laryngoscopy and intubation.
Other rigid fiberoptic scopes include the Upsherscope
(the Upsher Laryngoscope Corporation, Foster
City, CA, USA) and the WuScope (Actis Corporation,
Dublin, CA, USA).
None of these devices has undergone rigorous trials in
the ED to compare them with conventional means of
managing the airway. Watts described a comparison of
the time required for intubation and the degree of cervical
extension utilizing the Bullard scope and direct laryngoscopy,
both with and without in-line cervical immobilization,
in patients under general anesthesia (154).
The degree of spine extension and the time to intubation
were similar, except when cervical immobilization was
imposed, at which time the average duration required for
intubation with the Bullard laryngoscope was significantly
prolonged, from 25–40 sec. However, Schulman
reported in a randomized trial in 50 patients under anesthesia
that, in comparing the Bullard scope to a flexible
fiberscope during in-line cervical immobilization, intu-

44 S. L. Orebaugh
bation was significantly easier to accomplish, and required
less time with the rigid apparatus (155).
The Upsherscope, a relatively new rigid scope incorporating
a C-shaped steel blade with enclosed fiberoptic
bundles and an intubation channel, proved to have no
advantage over direct laryngoscopy in enabling intubation
in a group of 300 patients randomly assigned to
airway management in the OR by either technique (156).
In fact, the authors reported a 15% failure rate with the
Upsherscope, compared to only 3% with direct laryngoscopy.
Yet another rigid fiberoptic scope, the WuScope,
was compared to direct laryngoscopy in 87 patients randomized
to either form of airway management during
in-line cervical immobilization to simulate potential cervical
injury during anesthesia for elective surgery (157).
The authors found similar rates of intubation success, but
longer times to intubation and lower glottic visualization
scores using the WuScope.
Surgical Airway
The time-honored means of obtaining a rapid definitive
airway when both intubation and ventilation fail is the
insertion of a tracheal tube through an incision in the
neck. Although discouraged in the early part of the 20 th
century because of complications occurring after the
procedure, chiefly subglottic stenosis, cricothyrotomy
was reestablished as a safe technique for airway management
after the paper by Brantigan appeared, documenting
a much lower complication rate than expected
(158). The technique involves a vertical incision in the
midline over the palpable laryngeal cartilages, followed
by a transverse incision in the cricothyroid membrane, or
a single transverse incision through the skin, s.c. tissue,
and cricothyroid membrane if the interval is palpable
(158,159). Recent studies have focused on the “rapid
four-step technique” for cricothyrotomy (160). Holmes
described its use in cadavers by inexperienced personnel,
and compared this method to the standard technique
(161). The authors reported equal success with each
method (88% vs. 94%, respectively), with identical complication
rates of 38%, but more rapid tracheal tube
insertion with the rapid four-step technique, which required
an average of only 43 sec compared to an average
of 134 sec for the conventional method. In another cadaver
model, Davis described a significantly higher incidence
of complications with the rapid four-step technique,
primarily cricoid cartilage fracture (162).
Cricothyrotomy also may be accomplished with a
wire-guided technique, similar to the Seldinger technique
for cannulating blood vessels. After puncture of the
cricothyroid membrane with a thin-walled needle and
aspiration of air to confirm position, a wire is advanced
through the needle, which is then removed. After a small
incision in the skin and insertion of a dilator, the airway
is inserted over the dilator and wire. In a randomized,
cross-over trial performed on cadavers, Chan et al. compared
the standard technique of cricothyrotomy to the
Melker wire-guided method (164). The authors found
that 14 of 15 physicians participating preferred the wireguided
technique, while overall success was similar for
both methods. Eisenberger reported that inexperienced
clinicians attempting to perform cricothyrotomy on cadavers
had a low success rate of only 60–70%, with
either the standard or wire-guided technique (165).
Whatever method is chosen to perform cricothyrotomy
by the emergency physician, this procedure remains
the most reliable and time-honored definitive airway
procedure in a “failed airway” scenario (37). The
morbidity and mortality of this technique, when carried
out for long-term airway management, appears to be
similar to that of tracheostomy (158,166).
In the prehospital realm, surgical airways generally
have been employed for massively injured patients with
significant facial trauma. Spaite described attempted cricothyrotomy
in 16 patients with an 88% success rate, and
a complication rate of 31% (167). Boyle, in a retrospective
study of cricothyrotomy by flight nurses in a teaching
hospital helicopter program, described 69 attempts of
this procedure among 2108 patients transported. The
procedure was accomplished successfully in 98.5% of
cases with only one failure, and a low complication rate
of 8.7% (168).
Preventing the “Failed Airway”
Perhaps the best means of coping with the problem of
difficult intubation or failed airway is to prevent their
occurrence altogether. This requires that the initial attempt
at direct laryngoscopy is optimized, in order to
avoid repeated attempts at intubation that may cause
bleeding and swelling in the pharynx and supraglottic
area, and then a vicious cycle in which each attempt
leads to a greater likelihood of failed intubation and
ventilation with potentially disastrous consequences
(41). Optimizing laryngoscopy requires appropriate positioning
of the patient to align the pharyngeal, oral, and
laryngeal axes for visualization of the glottis; effective
muscle relaxation with an appropriate dose of succinylcholine
or a nondepolarizing agent; the use of a laryngoscope
blade type and size which best fits the situation;
and the use of optimal external laryngeal pressure by the
laryngoscopist (41,169). In this maneuver, laryngeal
pressure is exerted by the right hand during laryngoscopy,
to maneuver the larynx into a position in which the
glottis can be best seen. An assistant then maintains this

Difficult Airway Management 45
Figure 6. Optimal external laryngeal pressure requires laryngoscopist
to utilize right hand to manipulate the larynx while
viewing the glottis with the laryngoscope, before grasping
the ETT, and then requesting an assistant to maintain this
directed pressure while the tube is placed in the airway by
the now-liberated right hand (reprinted with permission by
Mosby Year-Book (36)).
directed pressure while the laryngoscopist accepts and
places the ETT with the right hand. The maneuver,
which initially seems awkward, is rapidly learned, and
has been shown to substantially improve the laryngoscopic
view in most patients (Figure 6) (170). Alternately,
the assistant may apply pressure “backwards,
upwards and rightwards” (BURP maneuver) (169).
When all of these factors are taken into account, the first
attempt at laryngoscopy is likely to be the best attempt,
without loss of precious seconds to correct suboptimal
aspects of the procedure after a poor view of the glottis
becomes evident.
CONCLUSIONS
Emergency physicians manage the airway with great
efficacy for the vast majority of cases that present to the
ED requiring such intervention. However, a small subset
of patients will cause difficulty in laryngoscopy, intubation,
and BVM ventilation, because of either unfavorable
anatomy or facial, airway or cervical pathology. This is
more likely in the ED than elsewhere in the hospital
because of the emergent nature of most airway management
and the inability to assess the patient ahead of time.
A large variety of adjuncts are available for assistance
with both intubation and ventilation. Identifying a set of
tools and techniques with which the practitioner is familiar
and comfortable can serve to alleviate anxiety and
improve efficiency when direct laryngoscopy is insufficient
to manage the airway. Optimizing direct laryngoscopy
with attention to patient positioning, muscle relaxation,
type of laryngoscope blade, and external laryngeal
pressure serves to reduce the incidence of poor laryngoscopic
visualization. For those situations in which adjuncts
are not useful or in which ventilation by BVM is
impossible, direct access to the larynx via a surgical
airway or transtracheal jet ventilation is necessary.
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