manejo_de_la_via_aerea_dificil - Verónica Bernal

Vista previa del material en texto

Management of the difficult airway:
alternative airway techniques and adjuncts
Kenneth H. Butler, DO, FACEPa,*, Brian Clyne, MDb
aEmergency Medicine Residency Program, Division of Emergency Medicine,
Department of Surgery, University of Maryland School of Medicine,
419 West Redwood Street, Suite 280, Baltimore, MD 21201, USA
bDivision of Emergency Medicine, Brown University School of Medicine,
593 Eddy Street, Samuels 2, Providence, RI 02903, USA
Management and stabilization of the airway is the single most important
procedure in emergency medicine and truly defines the specialty. No other
organ system can be resuscitated successfully without its securement.
Emergency physicians are frequently called on to provide expeditious
airway interventions for patients in extremis, many of whom have acute
respiratory deterioration and airway compromise under the most difficult
circumstances. Failure to secure a patient’s airway can lead to permanent
neurologic damage or death in a matter of minutes. Often, little time is
available to obtain an adequate patient history or to prepare the patient
as in conventional airway management. Accordingly, the few seconds or
minutes spent in evaluation, planning, and preparation for such scenarios
can make the difference between life and death. To provide optimal care
under these circumstances, the emergency physician must be skilled in a
variety of methods in airway management and have the proper equipment
and devices available at all times.
As the specialty of emergency medicine matures, physicians are becoming
increasingly proficient in airway management and are relying less frequently
on assistance from other medical specialties [1]. Despite this trend, a national
survey of emergency medicine residency training programs showed that only
half of these programs provided any experience with an alternative device
and little training in nonsurgical approaches to the difficult airway [2]. Many
emergency physicians thus graduate from residency programs with in-
adequate training in the management of a difficult airway. Residency
Emerg Med Clin N Am
21 (2003) 259–289
* Corresponding author.
E-mail address: kbutler@smail.umaryland.edu (K.H. Butler).
0733-8627/03/$ - see front matter � 2003, Elsevier Inc. All rights reserved.
doi:10.1016/S0733-8627(03)00007-5
workshops on airway management tend to focus on standard laryngoscopic
procedures and seldom cover alternative methods for managing a difficult
airway. As a result, most graduating physicians are more competent in estab-
lishing a surgical airway than in applying alternative nonsurgical airway
skills, even though new Advanced Cardiac Life Support (ACLS) guidelines
include the laryngeal mask airway (LMA) and esophageal-tracheal Com-
bitube (ETC) as better alternatives to facemask ventilation and as accept-
able alternatives to tracheal intubation [3].
Despite technologic advances and the development of new devices for
airway management, rapid-sequence intubation (RSI) remains the standard
of care in the practice of emergency medicine. Direct laryngoscopy remains
almost exclusively the manner in which all emergency airways are secured.
Numerous emergency department (ED) case series and multicenter studies
have shown intubation success rates at or greater than 98% using RSI and
direct laryngoscopy. Standard laryngoscopic intubation, however, may not
provide a definitive airway in every patient with a difficult airway. Instead of
repeating the standard approach and increasing complications, the clinician
should consider an alternative device or method of securing the airway.
Furthermore, clinical pathways for controlled situations, such as the awake
intubation arm of the American Society of Anesthesiologists difficult airway
algorithm (Fig. 1) [4,5], are not applicable to the acuity of the ED patient
who is agitated, hypoxic, and traumatized, with bloody secretions and
vomitus. As these patients tend to be our ‘‘difficult airways,’’ reliance on
preparation, prediction, evaluation, and familiarity with an alternative
airway management device will increase our rate of successful intubation.
The incidence of difficult intubations in the ED cannot be extrapolated
from the anesthesiology literature. It seems reasonable to expect that difficult
airways will be more frequent in EDs than in operating rooms, given the
urgent need for the procedure and the lack of preparation of the patient [6].
When assessing a patient in need of airway support, the emergency physician
first should attempt to identify clinical clues that suggest the presence of
a difficult airway and, when appropriate, select an alternative device. This
strategy can prevent a patient’s deterioration or demise caused by multiple
attempts using standard methods. Alternative devices and techniques include
the laryngeal mask airway, dual-lumen devices, tracheal introducers,
transillumination intubation, flexible fiberoptic scopes, and semi-rigid stylets.
Fig. 1. Difficult airway algorithm. *Nonsurgical tracheal intubation choices consist of
laryngoscopy with a rigid laryngoscope blade (many types), blind orotracheal or nasotracheal
technique, fiberoptic/stylet technique, retrograde technique, illuminating stylet, rigid broncho-
scope, and percutaneous dilational tracheal entry. Always consider calling for help (eg,
technical, medical, surgical) when difficulty with mask ventilation or tracheal intubation is
encountered. ++Consider the need to preserve spontaneous ventilation. From Benumof J. The
laryngeal mask airway and the ASA difficult airway algorithm. Anesthesiology 1996;84:686–99;
with permission.
c
260 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
261K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
The American Society of Anesthesiologists Task Force on Management of
the Difficult Airway defines a difficult airway as a ‘‘clinical situation in
which a conventionally trained anesthesiologist experiences difficulty with
mask ventilation, difficulty with tracheal intubation, or both’’ [7]. The task
force defines difficult mask ventilation as occurring when it is not possible to
maintain the PO2 [ 90% using 100% oxygen and positive pressure mask
ventilation, and difficult intubations as occurring when more than three
attempts are required using conventional laryngoscopy. Despite careful
preprocedure evaluation, airway management difficulties may not be pre-
dicted in some cases; therefore, strategies for managing the unanticipated dif-
ficult airway should be formulated and practiced. The ‘‘A’’ in the ABCs also
can represent an ‘‘alternative device’’ in airway management.
Prediction of the difficult airway
One single preprocedural indicator specifically for determining a difficulty
in ventilation, laryngoscopy, or intubation has not been found. The grading
tools used by anesthesiologists provide accuracy in the preoperative as-
sessment of stable patients. In contrast, emergency patients are difficult to
assess. They are acutely decompensating, have a low margin for safety,
hypoxemia, hypertension, hypotension, and other stressors, and require
rapid intubation under suboptimal conditions. Often they are in extremis,
agitated, and combative, have facial or laryngeal trauma, full stomachs, and
cervical immobilization, and are unable to speak, making any assessment
extremely difficult.
Some predictors have proven consistently useful; combinations of
predictors are the most sensitive. The most used predictive scheme for
airway assessment in anesthesiology is the Mallampati classification. This
system assigns three gradations based on increasing difficulty in visualizing
the posterior pharyngeal structures to predict difficult laryngeal exposure
(Box 1) [8]. Samsoon and Young modified the Mallampati scoring system
Box 1. Mallampati airway classification system
Class I Soft palate, fauces, uvula, anterior and posterior tonsillar
pillars are visible
Class II Soft palate, fauces, uvula are visible
Class IIISoft palate, base of uvula are visible
Class IV Soft palate not visible at all
Reproduced with permission from Deem S, Bishop MJ: Evaluation and
management of the dicult airway. Crit Care Clin 1995; 11:1–27 (citing Mallampati
SR, Gatt SP, Gugino LD, et al. A clinical sign to predict dicult tracheal intubation:
a prospective study. Can Anaesth Soc J 1985;32:429–34.)
262 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
into four classes; increasing class number suggests greater difficulty in glottic
exposure (Fig. 2) [9]. This predictive score evaluates the size of the tongue in
relation to the oropharynx, which indicates the ease or difficulty of achieving
optimal visualization. Airway assessment scoring systems have been based
on variables such as the evaluation of mouth opening, jaw size, thyromental
distance, and cervical range of motion, each individually having limited
sensitivity and specificity. Combining scoring systems provides better
prediction. The ‘‘Rule of Threes’’ offers the simplest predictor at the bed-
side. If the examiner can place three finger breaths (approximately 6–7 cm)
between the upper and lower teeth, between the mandible and the hyoid
bone, and between the thyroid cartilage and the sternal notch, direct
laryngoscopy is usually successful [10]. Significant difficulty with two or
more of these components justifies a more detailed assessment, because the
probability of difficulty increases threefold. Predictors of difficult bag-valve-
mask (BVM) ventilation (ie, high body mass index, advancing age, presence
of a beard, lack of teeth) also should be factored into a prediction, because
recent evidence suggests the incidence of failure with this technique may be
higher than previously believed [11]. In the presence of predictors of airway
difficulty, the use of an alternative device should be anticipated.
Preparation
The frequency of failed intubations in the emergency department is
approximately 1 in 500 [12]. The single most important factor in dictating
the success or failure of airway management remains the skill level of the
airway manager. The intubating physician must be familiar with various
types of airway equipment and must select and apply the appropriate device
Fig. 2. Samsoon and Young modification of Mallampati classification, evaluating relative size
of oropharyngeal structures to predict difficulty in laryngeal exposure during direct
laryngoscopy. Higher class number suggests greater difficulty in glottic exposure. From
Samsoon GLT, Young JRB. Difficult tracheal intubation. Anaesthesia 1987;42:487–90; with
permission.
263K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
or technique for every airway resuscitation. Knowledge of and skill main-
tenance for ‘‘plan B’’ strategies prepares the intubator for difficult cases
and facilitates establishment of a stable airway if initial intubation attempts
fail. The airway manager must check all airway equipment personally
before each emergency department shift. Equipment should be arranged
in an easily accessible order at the head of the bed.
Prehospital intervention
The difficult airway may first declare itself in the field when emergency
medical services (EMS) personnel report that multiple attempts using
standard laryngoscopic techniques failed, that the patient remained agitated
and combative because of hypoxia, or that intravenous (IV) access could not
be established. Although paramedics are well trained in airway management
and frequently respond to patients in respiratory distress, one fourth of
endotracheal tubes (ETTs) inserted by prehospital personnel in urban EMS
systems are misplaced [13]. All patients intubated in the field must have their
airway reassessed in the ED. Direct laryngoscopic confirmation of ETT
placement and use of a colorimetric or end-tidal carbon dioxide (ETCO2)
detector should be first priorities on arrival. Pediatric patients may not
benefit from endotracheal intubation if BVM ventilation can be performed
properly by EMS personnel. The addition of out-of-hospital endotracheal
intubation (ETI) to a paramedic scope of practice that already included
BVM ventilation did not improve survival or neurologic outcome of
pediatric patients in an urban EMS system [14]. A detailed mental picture
of the patient’s condition and stability of the airway conveyed by radio
transmission should help ED personnel prepare the resuscitation room
before the patient’s arrival.
The risk for intubation failure increases if the resuscitation room
equipment is not inventoried properly and checked routinely for proper
function. The simple mnemonic S-O-A-P-ME [15] should be used in the
anticipatory phase and facilitates a ‘‘clean’’ intubation: S ¼ suction,
O ¼ oxygen, A ¼ airway equipment, P ¼ pharmacologic agent, ME ¼
monitoring equipment. In this phase, the intubator checks the suctioning
device and connection, selects the appropriate BVM and attachment to a wall
oxygen source, verifies illumination of the laryngoscope blade, ensures
accessibility of sedation and paralytic drugs, and prepares all mechanical
monitoring equipment.
Initial evaluation
On arrival at the ED, all patient moorings should be checked, secured,
and transferred to a permanent source. A second IV line should be
established, as many placed in the field have been infiltrated or lost as a result
264 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
of physical movement. Patients should be rehydrated, as their insensible
water loss has been increased by tachypnea. Adults should receive a liter
of normal saline before intubation if their cardiopulmonary status per-
mits. Fluid administration may decrease the incidence of postintubation
hypotension caused by the change from negative intrathoracic pressure to
the positive intrathoracic pressure of mechanical ventilation. The decrease in
venous return associated with an increase in intrathoracic pressure leads to
a decrease in cardiac output and a subsequent decrease in blood pressure
[16]. The patient’s anatomic airway should be evaluated in tandem with
physiologic monitoring.
In 1993, the American Society of Anesthesiologists published an
algorithm for management of difficult intubations in the operating room
[4]. An update published in 1996 (Fig. 1) incorporates the laryngeal mask
airway. As in preprocedure assessments, this algorithm for stable patients
may not be applicable to the practice of emergency medicine. In the ED,
intubation is conducted to secure the airway and prevent the underlying
condition from causing rapid deterioration. Obstruction, trauma, altered
level of consciousness, respiratory and pulmonary failure, or underlying
shock does not allow the option of bringing the patient out of anesthesia to
resume spontaneous ventilation or awakening the patient if difficulty is
encountered, as recommended in the algorithm. In addition, the ASA
suggestion to ‘‘cancel the case and regroup’’ may not be realistic for
emergency medicine physicians, especially those in community hospitals.
Emergency physicians must optimize their first attempt at intubation. If
failure is inevitable, they must provide proper BVM ventilation and be
skilled in at least one alternative device for securement of the airway.
Aids to ventilation
The laryngeal mask airway
The laryngeal mask airway (LMA) (North America, Inc., San Diego,
CA) is an innovative airway management device intended as an alternative
to facemask use. For ventilation, the LMA is more effective than a BVM
alone in anesthetized patients, because BVM ventilation often requires two
hands to maintain a good seal [17]. The LMA provides an effective
emergency airway in a variety of crisis situations. For anesthesiologists and
anesthetists, the LMA is likely the most familiar first option in the algorithm
for managing a difficult airway (Fig. 3) [5].
The LMA consists of a semirigid tube attachment and an inflatable mask
that is placed into the hypopharynx and advanced over the larynx. Wheninflated, the mask cuff provides a seal around the glottic aperture (Fig. 4)
[18]. The LMA is available as a reusable latex-free device and as a disposable
one. Sizes range from those appropriate for neonates to large adults. If
endotracheal intubation has failed, the LMA may be successful [4].
265K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
266 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
Insertion technique
The LMA lies in a supraglottic position in the hypopharynx, and its ease
of insertion is usually independent of anatomic and pathologic factors
associated with the difficult airway (Box 2). Placement of the LMA is
unrelated to the Mallampati [23], Cormack, and Lehane scores, and is
unaffected by manual inline stabilization or the presence of a rigid cervical
collar [24].
Once the LMA is inserted, its aperture is lined up anatomically with the
glottis, which makes it useful as an aid to intubation while giving oxygen
and monitoring ventilation by way of capnography (Fig. 5). Hypoxic
damage resulting from persistent conventional attempts to intubate a
cyanotic patient may be avoided. Cricoid pressure can be maintained with
the LMA in situ [25]. Once hypoxia is resolved, an alternative technique can
be considered if the need for endotracheal intubation remains (eg, use of
a flexible fiberoptic scope).
Indications and advantages
When a surgical airway is being considered, an attempt to ventilate with
the LMA may be beneficial simply because it usually can be inserted within
Fig. 4. The components of the laryngeal mask airway. From LMA North America, Inc., San
Diego, CA; with permission.
Fig. 3. The laryngeal mask airway (LMA) fits into the ASA algorithm on the management of
the difficult airway in five places, as an airway (ventilatory device) or a conduit for a fiberscope.
From Benumof J. The laryngeal mask airway and the ASA difficult airway algorithm.
Anesthesiology 1996;84:686–99; with permission.
b
267K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
Fig. 5. Dorsal view of the laryngeal mask airway, showing position in relation to pharyngeal
anatomy. From LMA North America, Inc., San Diego, CA; with permission.
Box 2. Primary advantages of the laryngeal mask airway in
management of the difficult airway
Reliance on direct visualization of the cords for successful airway
control is obviated [19,20].
Neuromuscular blockade is not required for insertion and
function (but obtunded airway reflexes are required) [20].
The LMA usually can be inserted readily despite abnormal
supraglottic anatomy. [19,21] It is not recommended for
patients with acute epiglottitis. Intraglottic problems may
impede LMA effectiveness after placement.
The LMA can be used alone or as an aid to endotracheal
intubation [20,22].
Adapted from Pollack CV Jr. The laryngeal mask airway: a comprehensive
review for the emergency physician. J Emerg Med 2001;20(1):53–66.
268 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
a few seconds and the first-pass success rate is high [26]. In cardiopulmonary
resuscitation, the LMA has been used successfully by physicians, nurses,
and paramedics [27–29]. Its insertion is independent of anatomic features
used to predict or score difficult intubation and is not impeded by manual in-
line cervical immobilization or a rigid collar [30]. It can even be inserted in
prone patients and those with otherwise ‘‘inaccessible’’ airways [31,32]. The
LMA has demonstrated usefulness for difficult airway management in
children and adults. The Pediatric Emergency Medicine Committee of the
American College of Emergency Physicians advocates the LMA as ‘‘the
optimum alternative when RSI is unsuccessful’’ [33].
The success rate of the application of the LMA depends on the operator’s
familiarity with the device. The standard LMA may be used as a conduit for
passing an ETT by way of a gum elastic bougie, flexible fiberoptic scope, or
lighted stylet, but its use as an adjunct for these procedures is expected to
decline now that the intubating LMA is available [34–36]. The LMA also
may be a conduit for the administration of resuscitation medication.
Epinephrine and aerosolized albuterol have been delivered successfully by
way of the LMA [37,38].
Contraindications and disadvantages
The most important issue mitigating use of the LMA in the ED is the risk
for aspiration of gastric contents. Unlike an ETT with an inflated cuff, the
ventilating device does not physically separate the respiratory and alimentary
tracts [39]. Another contraindication to the use of the LMA for ventilation is
the need for high pulmonary inflation pressures because of increased airway
resistance or very low lung compliance. Inadequate ventilation because of air
leakage and gastric distention are the predictable adverse effects of
attempting positive-pressure ventilation in tight asthmatics.
The primary limitation of the LMA is the concern over incomplete
protection of the airway. This should not be considered an absolute con-
traindication to its use because a living patient with aspiration pneumonitis
is preferable to a patient dead for lack of an airway.
The primary concerns about use of the LMA are (1) the risk for gastric
insufflation, (2) the potential for inadequate ventilation because of sub-
optimal positioning, and (3) the inability to generate high inflation pressures
in bronchospastic patients. Table 1 compares the LMA with other means of
ventilation in patients with difficult airways.
The intubating LMA
The intubating LMA (ILMA) (LMA-Fastrach, Gensia Automedics, San
Diego, CA) was designed specifically for blind tracheal intubation. The
ILMA functions as an airway in the same fashion as the LMA. Its shorter,
wider ventilating conduit makes the ILMA easy to pass or withdraw over
a translaryngeal tube.
269K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
Insertion technique
A redesigned, tapered tracheal tube is passed blindly through the ven-
tilating airway (Fig. 6). The orotracheal tube can be as large as 8 mm. The
ILMA has a flat metal handle that projects posteriorly. This allows the intu-
bator to stand above the head of a supine patient and reposition the ILMA
for blind attempts to pass the tracheal tube.
Indications and advantages
The ILMA is indicated in anticipated or unexpected difficult airway
situations and for use as a guide for intubation of the trachea. Similar to the
LMA, the ILMA does not reliably protect the airway from regurgitation and
aspiration, but in the emergency pathway of ‘‘cannot intubate, cannot
ventilate,’’ the risk for aspiration must be weighed against the potential for
establishing an airway. Burgoyne and Cyna compared the ILMA and LMA
for ease of insertion and successful ventilation when used by inexperienced
resuscitators (nonanesthetic personnel). There were no clinically relevant
differences in the mean time to airway insertion (within 2 minutes), successful
ventilation, or expired tidal volume [40]. Emergency physicians using the
Table 1
Comparison of laryngeal mask airway (LMA) with other approaches for difficult or failed
airways
Characteristic
ET
intuba-
tion
LMA/
intubating
LMA BVM Combitube�
Lighted
stylet
Fiber-
scope
Surgical
airway
Avoidance of
laryngoscopy
0 ++++ ++++ ++++ +++ ++ ++++
Avoidance of
esophageal
intubation
++ ++++ ++++ + ++ ++ +++
Ease of placement ++ +++ +++ +++ ++ + +
Allows ventilation
without intubation
0 ++++ ++++ +++ NA 0 NA
Patient tolerance + +++ +++ + + ++ +
Cardiovascular/
sympathetic
response
++ +++ ++++ ++ ++ +++ +++
Aspiration risk ++ +++ ++++ ++ ++ ++ +++
PPV requirement ++++ ++ +++ +++ NA NA ++++
Security of airway ++++ +++ + ++ NA NA +++
Use with distorted
facial anatomy
++ ++++ + ++ + + +++
Pediatric use ++++ ++++ +++ 0 0 ++ +
Anesthetic depth +++ +++ + ++++ +++ ++ NA
Learning curve + +++ +++ ++++ ++ + +
Abbreviations: BVM, bag, valve, mask; NA, not applicable; PPV, positive pressure
ventilation.From Pollack CV Jr. The laryngeal mask airway: a comprehensive review for the emergency
physician. J Emerg Med 2001;20:53–66.
270 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
ILMA for the first time achieved ventilation in less than 15 seconds and
tracheal intubation in less than 1 minute [41]. In a large study involving 245
patients with difficult airways (ie, patients with Cormack-Lehane grade 4
views, immobilized cervical spines, airways distorted by tumors, surgery, or
radiation therapy, or wearing sterotactic frames), insertion of the ILMA was
accomplished in three attempts or fewer. The overall success rates for blind
and fiberoptically-guided intubation through the ILMA were 96.5% and
100%, respectively, suggesting the device is useful in the emergent treatment
of patients for whom intubation with standard rigid laryngoscopic failed
[41,42]. The ILMA also has been compared with fiberoptic intubation for
management of the difficult airway and proved to have a high success rate and
a comparable time to achieve tracheal intubation [43]. The ILMAalsomay be
used in children who weigh more than 30 kg (Table 2). Most investigators
agree that proficiency in use of the ILMA requires practice in a controlled
setting before it can be used successfully under emergent circumstances.
Fiberoptic intubation
Flexible fiberoptic intubating scopes have become more advanced and
geared to use in the emergency setting. Scopes have become smaller in
diameter, compared with those used by pulmonologists, and completely
Fig. 6. Insertion technique for intubating laryngeal mask airway (LMA-Fastrach). If no
resistance is felt, continue to advance the ETT while holding the LMA-Fastrach steady until
intubation has been accomplished. From Gensia Automedics, Inc., San Diego, CA; with
permission.
271K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
portable. Their built-in battery light source eliminates the time-consuming
setup and connection to a bulky power source.
Fiberoptic intubation, like all alternatives to RSI, has a place in airway
management for selected patients. Awake intubation benefits patients with
marked laryngeal or cervical pathology, for whom paralysis and suppression
of the respiratory drive or insertion of a laryngoscope blade may be detri-
mental. A study of more than 13,000 intubations demonstrated that a simple
algorithm for endotracheal intubation confined to only two methods (con-
ventional or fiberoptic intubation) is reliable, successful (failure rate,
0.045%), and easy to learn [44].
Insertion technique
The nasotracheal approach to the airway with a flexible fiberoptic scope
is often simpler than the oral approach because the instrument is aimed
directly at the glottis as it emerges from the nasopharynx into the hypo-
pharynx. Intubation over a fiberoptic scope can be performed successfully
through an LMA and around the ETC.
Indications and advantages
There are many advantages to the use of this technique, including
application to all age groups, excellent airway visualization, ability to in-
sufflate oxygen during the procedure, high success rate, and immediate con-
firmation of ETT placement [45].
Contraindications and disadvantages
There may be difficulty in the use of a fiberoptic scope in the emergency
setting. The presence of uncontrolled secretions, mucus, or active bleeding
markedly impairs visualization. Suction through these instruments is
Table 2
Larynegeal mask airway (LMA) and intubating LMA sizes and maximum cuff inflation
volumes
Mask
size
Patient
description
Available in
LMA-ClassicRM
Available in
LMA-Unique�
(disposable)
Available in
LMA-Fastrach�
(intubating LMA)
Max. cuff
volume (cc)
1 Infants up to 5 kg X 4
1.5 Infants 5–10 kg X 7
2 Infants and
children 10–20 kg
X 10
2.5 Children 20–30 kg X 14
3 Children 30–50 kg X X X 20
4 Adults 50–70 kg X X X 30
5 Adults 70–100 kg X X X 40
6 Large adults >100 kg X 50
From Pollack CV Jr. The laryngeal mask airway: a comprehensive review for the emergency
physician. J Emerg Med 2001;20:53–66.
272 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
ineffective. Attaching an oxygen source to the suction channel may increase
the field of view by blowing away offending secretions or debris. Advance-
ment of the ETT over the fiberoptic scope may be difficult, as the bevel of
the tube may catch on the arytenoids, cartilages, or aryepiglottic folds.
Withdrawing and rotating the ETT 90� and readvancing or changing to
a smaller tube usually solves this problem.
In a study of 60 consecutive intubations using a flexible fiberoptic
nasotracheal technique, the failure rate was 13% and bleeding occurred
in 22%, demonstrating its limitations [46]. Other emergency department
studies have shown that immediate airway control is often difficult with
fiberoptic-aided endotracheal intubation; therefore, the technique should be
used only in selected patients [47]. In a study of ED practices at U.S.
teaching hospitals, Levitan found that fiberoptic intubation was seldom
used as a means of managing the difficult airway [2].
Barriers to the selection of flexible fiberoptic intubation include the
following: (1) it is not standard equipment in most emergency departments,
(2) an initial training period is required, (3) the learning curve is steep, and
(4) skills decay because the procedure is used so infrequently.
Combitube
The esophageal-tracheal Combitube (ETC) (Combitube�, Kendall-
Sheridan Catheter Corp, Argyle, NY) is a blindly inserted, double-lumen
tube designed to facilitate ventilation during cardiopulmonary resuscitation
(CPR) [12]. Its predecessor, the esophageal obturator airway (EOA), led
to complications such as esophageal rupture and tracheal obstruction,
prompting an improved design [48]. The ETC combines the concept of the
EOA with that of the ETT. The device consists of two lumens:
a ‘‘pharyngeal’’ lumen and a ‘‘tracheal’’ lumen separated by a partition
wall. One lumen has an open distal end, similar to an ETT, and the other is
closed at the distal end, with multiple ventilating eyes proximal to its
inflatable cuff. A second larger oropharyngeal balloon inflates to secure the
ETC in position. Because ventilation is possible through either lumen, the
Combitube can be used after esophageal or tracheal insertion (Figs. 7, 8).
The device comes in two sizes: a 41 Fr for adult males and a 37 Fr
(Combitube� SA) for women and small adults.
Insertion technique
The ETC was designed to be inserted blindly; however, some investigators
recommend use of a laryngoscope to limit trauma and facilitate insertion
[48,49]. While grasping the patient’s tongue and jaw between the thumb and
forefinger, the clinician inserts the device to a depth at which the two black
ring markers are between the front teeth or alveolar ridges. With blind in-
sertion, there is a high probability the distal tip will enter the esophagus [48].
The oropharyngeal balloon is then inflated with 100 mL of air using the large
273K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
prepackaged syringe. This seals the tube in the posterior pharynx, limiting
aspiration of oral contents and minimizing movement. Next the esophageal
cuff is inflated with 15 mL of air, sealing the esophagus. Ventilation should be
attempted first through the pharyngeal lumen and the chest auscultated for
breath sounds. If breath sounds are absent or end-tidal CO2 is not present, the
distal tip was blindly inserted into the trachea and the patient should be
ventilated through the tracheal lumen and the chest again auscultated for
breath sounds. Tube placement can be confirmed by conventional means
such as auscultation, end-tidal CO2, and self-inflating bulb [50,51].
Fig. 7. The Combitube in the esophageal position. Reproduced with permission from
Combitube� and Combitube� SA (Small Adult) dual-lumen airways; Kendall, a unit of Tyco
Healthcare Group, LP, Mansfield, MA.
274 K.H. Butler, B. Clyne / Emerg Med ClinN Am 21 (2003) 259–289
Indications and advantages
The Combitube is indicated as an alternative to endotracheal intubation
(ETI) for medical personnel unskilled in airway management. As such, it is
best suited for the prehospital setting, where patient positioning and
environmental conditions may preclude laryngoscopy. For those skilled in
airway management, the main indication for the Combitube is as a rescue
device for the failed airway or the ‘‘cannot intubate, cannot ventilate’’ sce-
nario in which cricothyrotomy is contraindicated, unsuccessful, or not im-
mediately available.
The main advantage of the Combitube for the emergency physician is
that it may obviate the need for cricothyrotomy in patients with failed
airways and those with maxillofacial or neck trauma [52]. The insertion
technique is easily learned, allowing medical personnel without training in
laryngoscopy to establish airway support in emergency situations. Studies of
untrained providers indicate that use of the Combitube is safe, effective, and
easily learned [53–55]. The ETC has been used successfully in the prehospital
Fig. 8. The Combitube in the tracheal position. Reproduced with permission from Combitube�
and Combitube� SA (Small Adult) dual-lumen airways; Kendall, a unit of Tyco Healthcare
Group, LP, Mansfield, MA.
275K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
environment and was preferred in one study over the LMA by emergency
medical personnel [56]. Oxygenation and ventilation using the Combitube
are comparable to, if not better than, those achieved with standard ETI, and
the Combitube may be used for prolonged ventilation [12,57].
It has been suggested that the ETC may offer an advantage over ETI in
patients with cervical spine injuries because it is inserted with the head and
neck in the neutral position, but this claim is not supported consistently by
the literature [58,59]. The Combitube offers adequate protection of the
airway from aspiration [60].
Contraindications and disadvantages
The Combitube is contraindicated in patients with intact laryngeal or
pharyngeal reflexes, known esophageal pathology, or corrosive ingestions. It
is also contraindicated in patients with upper airway obstruction caused by
a foreign body or pathologic conditions. The Combitube SA, designed for
small adults, should not be used in patients under 4 feet tall. It is not
available in pediatric sizes. As with other blind techniques, the ETC presents
the potential for esophageal or pharyngeal trauma. There are case reports of
subcutaneous emphysema resulting from piriform sinus perforation or
esophageal laceration, apparently caused by direct esophageal trauma
during ETC insertion [61–63]. Pneumomediastinum and pneumoperitoneum
also have been reported with its use [63]. Unlike an ETT, suction of tracheal
secretions is not possible with the Combitube.
The literature supports use of the ETC as an effective alternative to
endotracheal intubation. It is a noninvasive, easily acquired skill, and the
device functions when inserted into either the esophagus or the trachea.
Although its primary role is in prehospital care, emergency physicians
should be familiar with the device and consider it for difficult and failed
airway situations. Whenever conventional intubation cannot be performed
readily, the Combitube may be a useful alternative.
Lighted stylet
Light-guided intubation evolved from the observation that a bright light
transilluminates the soft tissues of the anterior neck when placed in the
trachea [64]. Using this principle, several lighted stylets or light wand de-
vices have been developed for blind oral or nasal endotracheal intubation.
Among the more popular is the Trachlight� (Laerdal Medical, Armonk,
NY), a light wand device with three parts: (1) a reusable handle containing
a battery pack and light source, (2) a flexible tube with a light bulb at the distal
tip, and (3) and a retractable stylet within the light wand to provide stability.
Insertion technique
The lighted stylet should be lubricated and positioned within a standard
ETT so the light bulb is just at the distal end of the tube. The tube is then
276 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
bent to a sharp 90� angle just proximal to the endotracheal cuff to facilitate
insertion around the tongue and maximize light intensity at the anterior
neck. The intubator can approach the patient from the head or the side. The
tongue and jaw are gently pulled forward from the side of the mouth with
the nondominant hand and the ETT is inserted blindly into the back of the
mouth at the midline. The tip of the ETT then is moved gently anteriorly
until a bright, well defined glow illuminates the thyroid prominence (Fig. 9).
The stylet then is retracted 5–10 cm to allow flexibility at the tip and the tube
is advanced until the light disappears just below the sternal notch. At this
point, the tip of the ETT is reliably positioned between the cords and the
carina. The stylet then is removed, followed by standard confirmation of
tube placement.
Indications and advantages
Most emergency physicians have limited experience with lighted stylets
and continue to use direct laryngoscopy as the primary method of securing
the airway. In difficult airway situations, however, the lighted stylet is an
appropriate backup choice. Indications for the lighted stylet include difficult
airways caused by anatomic considerations, temporomandibular immobil-
ity, large overbites, restricted mouth opening, or poor dentition [26,65]. It
has been used as a nasotracheal or orotracheal adjunct for severe facial
trauma [66,67].
Lighted stylet intubation requires training, but proficiency is acquired
quickly and emergency physicians have used these devices with success [68].
Studies comparing lighted stylet intubation with direct laryngoscopy have
shown faster times to intubation, fewer intubation attempts, less trauma,
and fewer adverse hemodynamic effects with the stylet [68–71]. Also, in
patients with limited neck mobility or cervical spine injury, the lighted stylet
is able to negotiate oropharyngeal angles better than laryngoscopy, with
little or no head or neck manipulation [72]. In difficult airways, the light
wand can be used as intended or as a standard stylet to aid in direct
visualization of the cords.
Contraindications and disadvantages
There are no absolute contraindications to lighted stylets, but limitations
may be encountered in patients with known inflammatory laryngeal
disorders such as epiglottitis, retropharyngeal abscess, and tracheal stenosis.
They are relatively contraindicated in patients known to have laryngeal
tumors, polyps, foreign bodies, or an unknown cause of upper airway
compromise [73].
Factors such as copious oropharyngeal blood, dark skin, obesity, or
bright ambient lighting may limit the degree of transillumination achieved
with the lighted stylet. Conversely, in thin, fair-skinned patients, trans-
illumination may be present with esophageal placement [68]. It should be
277K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
stressed that lighted stylet intubation is a blind technique and tracheal
placement should be confirmed by standard means. Trauma to the upper
airway using the lighted stylet is generally minor (bleeding, dysphagia, sore
throat) and less common than with direct laryngoscopy.
For the emergency physician, lighted stylet intubation can be a valuable
tool in difficult airway situations. It is an easily learned technique that is
Fig. 9. Light-guided intubation with Trachlight� is based on the principle of transillumination
of the soft tissues in the neck. This technique takes advantage of the anterior location of the
trachea relative to the esophagus. A well defined, circumscribed glow can be seen in the anterior
neck when the endotracheal tube and light enter the glottic opening. If the tip of the tube is
placed in the esophagus, the light glow is diffuse and is not seen easily. Trachlight�illustration
courtesy of Laerdal Medical Corporation.
278 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
quick and reliable and has minimal complications. In the ED, it is best used
as a backup technique for the patient who cannot be intubated by
traditional laryngoscopy but who can be ventilated. For patients with
unstable cervical spine injuries or patients who cannot be intubated orally, it
may be a faster, more accessible first choice over fiberoptic intubation. As
with any airway device, preparation and frequent practice are essential to
maintain skills.
Gum elastic bougie
The gum elastic bougie or Eschmann stylet is an endotracheal tube
introducer originally described by Macintosh in 1949 as an aid to intubation
[74]. The standard bougie is a semirigid malleable device, 60 cm long, made
of woven polyester with a resin coating. It has a diameter of 15 Fr (5 mm),
allowing easier passage through the vocal cords, and has a 40� angle 3.5 cm
from its distal tip to facilitate tracheal placement [75]. A plastic, less
expensive version of the bougie is available in the United States as the Flex-
Guide endotracheal tube introducer (ETTI) (GreenField Medical Sourcing,
Inc., Northborough, MA) [76]. The bougie is commonly used in Europe for
difficult intubations and has reduced the incidence of failed intubation and
cricothyrotomy [76–78].
Insertion technique
When visualization of the vocal cords is poor or impossible, the
lubricated bougie is passed posterior to the epiglottis with the distal tip
angled anteriorly. If it enters the trachea, palpable clicks are felt as the tip of
the stylet passes over the tracheal cartilage rings. This ‘‘washboard’’ effect
and the fact the stylet cannot be passed beyond 40 cm (as the tip reaches the
small bronchi) are reliable signs of tracheal placement [79]. With esophageal
placement, clicks are not felt and the device can be advanced unobstructed
beyond 45 cm. With the bougie stabilized in place by an assistant and the
laryngoscope maintaining anterior displacement of the oropharyngeal
structures, an ETT is passed over the bougie into the trachea (Fig. 10).
Passage of the ETT is made easier by rotating the tube 90� counterclock-
wise, keeping the bevel of the tube posterior [80].
Indications and advantages
The bougie is indicated whenever anatomic, traumatic, or pathologic
factors prevent a good view of the vocal cords by direct laryngoscopy. It has
proven particularly useful in patients with airway edema, neck trauma, and
cervical spine immobilization [81–83]. It is reasonable to attempt one
bougie-assisted intubation before performing a cricothyrotomy in certain
failed airway situations. It should be stressed that the bougie is no substitute
for proper technique and should be used only after other attempts to
optimize the laryngoscopic view have failed.
279K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
The bougie is an inexpensive, nonsurgical device that can be readily
available for urgent use in the ED. Unlike other airway adjuncts, it requires
little training time and no technical expertise beyond the skill of lar-
yngoscopy. Its flexibility allows the airway manager to customize the
bougieto suit the patient’s anatomy and increase the likelihood of success.
When inserted properly, the bougie is reliable in avoiding esophageal
intubations.
Contraindications and disadvantages
The bougie is contraindicated when the epiglottis cannot be visualized
under any circumstances. Unlike some airway adjuncts, it is not a blindly
inserted device and should be guided under the epiglottis or through the
vocal cords under direct vision. It is not indicated for patients who require
nasotracheal intubation. The smallest ETT the standard bougie can
accommodate is a 6.0 mm ETT, limiting use to adults. Minor complications
associated with the bougie are uncommon and include local trauma to the
Fig. 10. Gum elastic bougie directed into the trachea. The endotracheal tube is inserted over the
bougie. From McCarroll SM, Lamont BJ, Buckland MR, Yates APB. The gum elastic bougie:
old but still useful [letter]. Anesthesiology 1988;68:643–4; with permission.
280 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
airway, sore throat, and hoarseness [84]. Major complications such as
pharyngeal perforation, pneumothorax, hemopneumothorax, and medias-
tinal emphysema have been reported only rarely [85,86].
The bougie is an inexpensive, easily used device and should be the first
backup device considered for the anticipated or known difficult airway.
Routine or difficult, a bougie should be kept within arm’s reach during every
intubation.
Digital intubation
Blind digital intubation or tactile intubation is an uncommon technique
in which the intubator guides the ETT into the trachea with his or her
fingers. The emergency physician has other devices and skills for manage-
ment of the difficult airway, but digital intubation deserves mention as a
valuable technique for some rarely encountered situations.
Technique
Using a stylet, the clinician forms an ETT into a U-shape. The intubator
approaches with the nondominant hand closest to the patient and an
assistant retracts the tongue. This pulls the epiglottis upward and facilitates
palpation of the epiglottis and glottic opening. The index and middle fingers
of the nondominant hand are inserted palm down toward the base of the
tongue. The middle finger is used to identify the epiglottis and direct it
anteriorly. The ETT with stylet is then passed between the index and middle
fingers and advanced into the glottic opening, guided by the middle finger.
The stylet is then withdrawn and placement is confirmed.
Indications and advantages
Digital intubation is indicated when poor lighting, patient positioning,
copious airway secretions, or equipment failure render direct laryngoscopy
difficult or impossible [87]. These situations are more likely to occur in the
prehospital setting than in the emergency department. Other indications
include cervical spine immobilization and disrupted airway anatomy. It
should be considered a last resort before cricothyrotomy for the failed
airway [88]. It can be performed as an adjunct to blind nasotracheal
intubation [89]. Other than an ETT and a stylet (and gloves), digital
intubation requires no technical equipment and can be performed rapidly in
poorly lit environments with the patient in any position, making it
particularly suitable to the prehospital setting. It has been used successfully
in pediatric patients and is preferred by some for neonatal resuscitation [90].
Contraindications and disadvantages
In the awake or semiconscious patient with intact oropharyngeal reflexes,
digital intubation is relatively contraindicated. Attempting this technique on
responsive patients can lead to oropharyngeal trauma and biting injuries.
281K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
Placing a bite block to prevent the patient from biting down reflexively and
double gloving may help minimize the risk for infectious disease trans-
mission. Other relative contraindications include caustic ingestion, thermal
burns, and upper airway foreign bodies.
The length of the intubator’s fingers relative to the dimensions of the
patient’s oropharynx is an important predictor of success. Factors such as
limited mouth opening, large teeth, and distorted anatomy can further place
the intubator at a disadvantage. Iatrogenic trauma to the upper airway is
possible but can be avoided with gentle technique. Esophageal intubation is
a concern with digital intubation; therefore, diligent confirmation of
tracheal placement is required.
Although rarely used, difficult to perform, and risky, digital intubation
can be a life-saving skill and can prevent the need for creation of a surgical
airway. It should be considered for select patients with difficult airways
when alternative techniques are unavailable or inoperative. As with any
airway technique, digital intubationrequires preparation and practice.
Retrograde intubation
Retrograde intubation (RI) is an invasive technique that involves
puncture through the cricothyroid membrane and passage of a guide wire
‘‘retrograde’’ into the oropharynx to facilitate ETT placement. Originally
described in 1960, RI is simplistic in principle but requires time and practice
to perform [91].
Technique
Commercially available kits for RI contain a syringe, an 18-gauge
introducer needle with catheter, a guide wire with a soft J-tip, and an
introducer catheter. Although RI is used most commonly for patients with
limited neck mobility, ideally the patient’s neck should be hyperextended.
The cricothyroid membrane is identified and, time permitting, local an-
esthesia is infiltrated after skin preparation. While the larynx is stabilized, an
18-gauge needle attached to a syringe partially filled with saline is used to
puncture through the cricothyroid membrane in a cephalad direction.
Aspiration of air confirms placement in the trachea. The guide wire is then
threaded through the needle cephalad into the oropharynx and is retrieved
under direct visualization using Magill forceps. The guide wire then can be
placed directly into the lumen of an ETT or through the Murphy eye of the
ETT. Passing the wire through the Murphy eye permits slightly more
advancement of the ETT below the vocal cords [92]. Alternatively, a guide
catheter can be placed over the guide wire to prevent lateral movement of
the ETT and ease its passage through the vocal cords [93]. With the ETT
advanced through the vocal cords and abutting the cricothyroid membrane,
the guide wire is pulled out through the proximal end of the ETT and the
ETT is advanced into its proper position. A common variation of this
282 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
technique involves threading a fiberoptic bronchoscope over the guide wire,
allowing direct visualization of the patient’s anatomy and the ability to
deliver continuous oxygen [94].
Indications and advantages
RI is indicated for the difficult airway resulting from cervical spine
immobilization, anatomic abnormality, or trauma, particularly upper
airway trauma that makes oral or nasal access difficult or impossible. It
should be considered when intubation has failed but adequate oxygenation
and ventilation can be maintained and when cricothyrotomy is impossible
or unavailable. RI has been used successfully in the prehospital setting and
the emergency department [95,96].
Contraindications and disadvantages
Relative contraindications to RI include unfavorable upper airway ana-
tomy such as flexion deformity of the neck, pretracheal mass or infection,
obesity, coagulopathy, and laryngeal injury [97]. Bleeding is a common
but generally minor problem with RI. Other potential complications
include subcutaneous emphysema, pneumomediastinum, infection, and
injuries to the trachea and laryngeal structures. Data on RI for the pediat-
ric population are limited, but the procedure seems to be useful and safe in
experienced hands, particularly with the adjunct use of a fiberoptic bron-
choscope [98].
Emergency physicians and anesthesiologists have used RI with success
for difficult airway management. It should be considered when cervical spine
immobilization, anatomic derangements, copious secretions, or blood
prevents adequate laryngoscopy, and after failed intubation when time
and patient status allow. Drawbacks to RI are that it is invasive, it can be
time consuming, and the equipment may not be readily available.
Jet ventilation
Percutaneous transtracheal jet ventilation (TTJV) involves puncturing
the cricothyroid membrane with a large-bore catheter for temporary
ventilation in failed airway situations. It is a simple, quick, and effective
technique associated with fewer complications than surgical cricothyrot-
omy. Although rarely performed, emergency physicians should be familiar
with this lifesaving skill for desperate, ‘‘cannot intubate, cannot ventilate’’
scenarios when surgical cricothyroidotomy is unavailable or unsuccessful. It
is considered the surgical airway of choice in children younger than 12 years
of age as a bridge to securing a definitive airway.
Technique
If permissible, the patient’s neck should be hyperextended while the
cricothyroid membrane is identified. With the larynx stabilized, a large-bore
283K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
(12- to 16-gauge) catheter-over-needle attached to a 20-mL syringe partially
filled with saline is directed caudally through the cricothyroid membrane.
Large-bore wire-coiled transtracheal catheters that are less likely to kink are
preferable to intravenous catheters. Tracheal puncture is marked by
aspiration of air bubbles. The needle is then withdrawn slightly and the
catheter is advanced over the needle and into the airway with the aid of a small
skin incision. The catheter should be advanced to the hub, and placement in
the trachea reconfirmed by aspiration of air. Once in place, great care should
be taken to stabilize the catheter andprevent subsequent air leak at the incision
site. The hub of the catheter is then connected to the jet ventilation system.
A variety of TTJV systems are available. The most commonly used is
composed of high-pressure tubing in line with a regulator, a pressure gauge,
and a jet ventilation toggle switch. The jet ventilation system is connected to
a wall oxygen source of 50 pounds per square inch (psi). In children older
than 5 years of age, the oxygen pressure should be down-regulated to 20–30
psi to prevent barotrauma, and in children younger than 5 years of age, a bag
should be used for ventilation. Ordinarily, less than 1 second of inspiration
is required to provide an adequate tidal volume to the lung, whereas
exhalation occurs passively because of the elastic recoil of the lung in 2–3
seconds. An inspiration to expiration ratio (I:E) of 1:3 therefore is
recommended to allow adequate time for exhalation and avoid barotrauma.
Maintaining upper airway patency by using a jaw thrust maneuver with
oropharyngeal and nasopharyngeal airways helps maximize exhalation,
preventing air trapping and high expiratory pressures.
Indications and advantages
In the emergency department, TTJV is rarely used. It is indicated for
‘‘cannot intubate, cannot ventilate’’ situations when a surgical airway is not
possible and when the equipment or personnel for conventional airway
management are unavailable. It is generally considered to be quicker and
less prone to complications than surgical cricothyrotomy; however, fa-
miliarity with the jet ventilator assembly is critical for rapid execution of this
technique [99]. It can be performed in all age groups and is the preferred
surgical airway in children.
Contraindications and disadvantages
Airway obstruction below the vocal cords and complete upper airway
obstruction render exhalation difficult or impossible and constitute relative
contraindications to TTJV. In these situations, surgical cricothyrotomy is
the best choice. Complications with TTJV are uncommon but include
subcutaneous emphysema, esophageal puncture, bleeding, exhalation dif-
ficulty, and barotrauma [100–103]. The catheter used in TTJV can become
kinked or obstructed and does not confer airway protection.
TTJV should be viewed as a temporary rescue technique, primarily for
children under 12 years of age, until a definitive airway can be established.
284 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
Despite the infrequent need for TTJV in the ED, emergency physicians
should be well versed in this technique for crisis situations.
Summary
Rapid-sequence intubation using conventional laryngoscopic technique
remains the standard of airway management in emergency medicine and
continues to have a success rate of approximately 98%. Preparation and
proper intubation technique must be optimized at the initial attempt using
direct laryngoscopy. Failure causes multiple repeatedattempts, leading to
a failed airway. Each repeated attempt increases the likelihood of bleeding,
oral, pharyngeal, and laryngeal edema, and malposition, causing decreased
visualization of the glottic opening, equipment failure, and hypoxia.
Preparation must be an ongoing process. Faulty suction, no oxygen source,
choice of the wrong laryngoscopic blade or ETT, poor light source, or
misplaced equipment can domino into mechanical failure. Intubation equip-
ment stations must be inventoried constantly, organized, and kept simple
in their layout to decrease confusion during selection. Medication for seda-
tion and paralysis should be readily available and not kept distant from the
intubation station in a medication-dispensing unit that would require time
for acquisition.
Proper positioning of the patient remains paramount for alignment of the
oral, pharyngeal, and laryngeal axis to provide optimal visualization of the
vocal cords. Proper technique during insertion of the laryngoscope blade in
the oral cavity for displacement of the tongue must be ensured. Without
proper technique, even with proper positioning, the glottic opening cannot
be visualized. Laryngeal pressure to maneuver the larynx into position
should be exerted initially by the laryngoscopist’s right hand and, when in
view, maintained by an assistant to free the laryngoscopist’s hand for ETT
insertion. With preparation and proper technique, the first attempt is the
best attempt, and the vicious cycle of multiple attempts and complications
will be averted.
Acknowledgment
The authors thank Linda J. Kesselring, MS, ELS, Division of Emergency
Medicine, University of Maryland School of Medicine, for help with
manuscript preparation.
References
[1] Ma OJ, Bentley B, DeBenhnke DJ. Airway management practices in emergency medicine
residencies. Am J Emerg Med 1995;13:501–4.
[2] Levitan RM, Kush S, Hollander JE. Devices for difficult airway management in academic
emergency departments: results of a national survey. Ann Emerg Med 1999;33:694–8.
285K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
[3] Barnes TA, MacDonald D, Noland J, et al. Airway devices. Proceedings of the
International Guidelines 2000 Conference for Cardiopulmonary Resuscitation and
Emergency Cardiac Care. Ann Emerg Med 2001;37(Suppl):S145–8.
[4] Caplan RA, Benumof JL, Berry FA, et al. Practice guidelines for management of the
difficult airway: a report by the American Society of Anesthesiology Task Force on
Management of the Difficult Airway. Anesthesiology 1993;78:597–602.
[5] Benumof JL. Laryngeal mask airway and the ASA difficult airway algorithm.
Anesthesiology 1996;84:686–99.
[6] Orebaugh SL. Difficult airway management in the emergency department. J Emerg Med
2002;22(1):31–48.
[7] Mallampati SR. Clinical signs to predict difficult tracheal intubations. Can Anaesth Soc J
1983;30:316–8.
[8] Mascia MF, Mattasck MT. Emergency airway management by anesthesiologists.
Anesthesiology 1993;79:A1054.
[9] Samsoon GLT, Young JRB. Difficult tracheal intubations. Anaesthesia 1987;42:487–90.
[10] Watson CB. Prediction of difficult intubation. Resp Care 1999;44:777–98.
[11] Langeron O, Masso E, Huraus C, et al. Prediction of difficult mask ventilation.
Anesthesiology 2000;92:1229–36.
[12] Frass M, Frenzer R, Zdrahal F, et al. The esophageal tracheal Combitube: preliminary
results with a new airway for CPR. Ann Emerg Med 1987;16:768–72.
[13] Katz SH, Falk JL. Misplaced endotracheal tubes by paramedics in an urban emergency
medical services system. Ann Emerg Med 2001;37(1):32–7.
[14] Gausche M, Lewis RJ, Stratton SJ, et al. Effect of out-of-hospital pediatric endotracheal
intubation on survival and neurological outcome: a controlled clinical trial. JAMA
2000;283(6):783–90.
[15] Strange GR, editor. APLS: The Pediatric Emergency Medicine Course. 3rd edition.
Dallas, Texas: American College of Emergency Physicians; and Elk Grove Village,
Illinois: American Academy of Pediatrics; 1998. p. 17–27.
[16] Hubmayr RD, Irwin RS. Mechanical ventilation: initiation. In: Irwin RS, Cerra FB,
Rippe JM, editors. Intensive care medicine. 4th edition. Philadelphia: Lippincott-Raven;
1999. p. 738.
[17] Brain AIJ. The laryngeal mask—a new concept in airway management. Br J Anaesth
1983;55:801–5.
[18] Pennant JH. Laryngeal mask airway. Anesthesiology 1993;79:144–63.
[19] Berry AM, Brimacombe JR, Verghese C. The laryngeal mask airway in emergency medi-
cine, neonatal resuscitation, and intensive care medicine. In: Ferson DZ, Brimacombe JR,
Brain AIJ, editors. The laryngeal mask airway. Int Airway Clin 1998;36(2):91–109.
[20] Brimacombe JR, Berry AM, Daves SM. The laryngeal mask airway. In: Hanowell LH,
Waldron RJ, editors. Airway management. Philadelphia: Lippincott-Raven Publishers;
1996. p. 195–211.
[21] King CJ, Davey AJ, Chandradeva K. Emergency use of the laryngeal mask airway
in severe upper airway obstruction caused by supraglottic oedema. Br J Anaesth 1995;75:
785–6.
[22] Aye T, Milne B. Use of the laryngeal mask prior to definitive intubation in a difficult
airway: a case report. J Emerg Med 1995;13:711–4.
[23] Brimacombe J, Berry A. Mallampati classification and laryngeal mask airway insertion.
Anaesthesia 1993;48:347.
[24] Pennant JH, Pace NA, Gajraj NM. Role of the laryngeal mask airway in the immobilized
cervical spine. J Clin Anesth 1993;5:226–30.
[25] Brimacombe J, Berry A. Effect of cricoid pressure on ease of insertion of the laryngeal
mask airway. Br J Anaesth 1994;71:800–2.
[26] Crosby ET, Cooper RM, Douglas MJ, et al. The unanticipated difficult airway with
recommendations for management. Can J Anesth 1998;45:757–76.
286 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
[27] Kokkinis K. The use of the laryngeal mask airway in CPR. Resuscitation 1994;27:9–12.
[28] Samarkandi AH, Seraj MA, el Dawlatly A, Mastan M, Bakhamees HB. The role of the
laryngeal mask airway in cardiopulmonary resuscitation. Resuscitation 1994;28:103–6.
[29] Stone BJ, Leach AB, Alexander CA, et al. The use of the laryngeal mask airway by nurses
during cardiopulmonary resuscitation: results of a multicentre trial. Anaesthesia 1994;
49:3–7.
[30] Asai T, Neil J, Stacey M. Ease of placement of the laryngeal mask during manual in-line
neck stabilization. Br J Anaesth 1998;80:617–20.
[31] Green MK, Roden R, Hinchley G. The laryngeal mask airway: two cases of prehospital
care. Anaesthesia 1992;47:688–9.
[32] McCaughey W, Bhanumurthy S. Laryngeal mask placement in the prone position.
Anaesthesia 1993;48:1104–5.
[33] Gerardi MJ, Sacchetti MJ, Cantor RM, et al. Rapid sequence intubation of the pediatric
patient. Ann Emerg Med 1996;28:55–74.
[34] Allison A, McCrory J. Tracheal placement of a gum elastic bougie using a laryngeal mask
airway. Anaesthesia 1990;45:419–20.
[35] Asai T. Fiberoptic tracheal intubation through the laryngeal mask in an awake patient
with cervical spine injury. Anesth Analg 1993;77:404.
[36] Benumof JL. Laryngeal mask airway: indications and contraindications. Anesthesiology
1992;77:843–6.
[37] Challiner A, Rochester S, Mason C, Anderson H, Walmsley A. Spread of intrapulmonary
adrenaline administered via the laryngeal mask. Resuscitation 1997;34:193.
[38] Spain BT, Riley RH. Salbutamol via the laryngeal mask for relief of broncospasm.
Anaesthesia 1992;47:1107.
[39] Asai T, Morris S. The laryngeal mask airway: its features, effects and role. Can J Anaesth
1994;41:930–60.
[40] Burgoyne L, Cyna A. Laryngeal mask vs intubating laryngeal mask: insertion and
ventilation by inexperienced resuscitators. Anaesth Intens Care 2001;29(6):604–8.
[41] Martel M, Reardon RF, Cochrane J. Initial experience of emergency physicians using the
intubating laryngeal mask airway: a case series. Acad Emerg Med 2001;8(8):815–22.
[42] Ferson DZ, Rosenblatt WH, Johansen MJ, et al. Use of the intubating LMA-Fastrach in
254 patients with difficult-to-manage airways. Anesthesiology 2001;95(5):1175–81.
[43] LangeronO, Semjen F, Bourgain JL, Marsac A, Cros AM. Comparison of the intubating
laryngeal mask airway with the fiberoptic intubation in anticipated difficult airway
management. Anesthesiology 2001;94(6):968–72.
[44] Heidegger T, Gerig HJ, Ulrich B, et al. Validation of a simple algorithm for tracheal
intubation: daily practice is the key to success in emergencies. An analysis of 13,248
intubations. Anesth Analg 2001;92:517–22.
[45] Ovassapian A, Schreaker SC. Fiberoptic aided bronchial intubation. Semin Anesth
1987;6:133–45.
[46] Delany KA, Hessler R. Emergency flexible fiberoptic nasotracheal intubation: a report of
60 cases. Ann Emerg Med 1988;17(9):919–26.
[47] Mlinek Jr EJ, Clinton JE, Plummer D, Ruiz E. Fiberoptic intubation in the emergency
department. Ann Emerg Med 1990;19(4):359–62.
[48] Frass M. The Combitube: esophageal/tracheal double lumen airway. In: Benumof JL,
editor. Airway management, principles and practice. St Louis: Mosby; 1996. p. 444–54.
[49] Wissler RN. The esophageal-tracheal Combitube. Anesth Rev 1993;20:147–52.
[50] Butler BD, Little T, Drtil S, et al. Combined use of the esophageal tracheal Combitube
with a colorimetric carbon dioxide detector for emergency intubation/ventilation. J Clin
Monit 1995;11:311–6.
[51] Salem MR, Wafai Y, Baraka A, et al. Effectiveness of the self-inflating bulb for
verification of proper placement of the esophageal tracheal Combitube. Anesth Analg
1995;80:122–6.
287K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
[52] Blostein P, Koestner A, Hoak S. Failed rapid sequence intubation in trauma patients:
esophageal tracheal Combitube is a useful adjunct. J Trauma 1998;44:534–7.
[53] Atherton G, Johnson J. Ability of paramedics to use the Combitube in prehospital cardiac
arrest. Ann Emerg Med 1993;22:1263–8.
[54] Staudinger T, Brugger S, Watschinger B, et al. Emergency intubation with the
Combitube: comparison with the endotracheal airway. Ann Emerg Med 1993;22:1573–5.
[55] Yardy N, Hancox D, Strang T. A comparison of two airway aids for emergency use by
unskilled personnel: the Combitube and laryngeal mask. Anaesthesia 1999;54:181–3.
[56] Rumball CJ, MacDonald D. The PTL, Combitube, laryngeal mask, and oral airway:
a randomized prehospital comparative study of ventilatory device effectiveness and cost-
effectiveness in 470 cases of cardiorespiratory arrest. Prehosp Emerg Care 1997;1:58–9.
[57] Frass M, Rodler S, Frenzer R, et al. Esophageal tracheal Combitube, endotracheal
airway, and mask: comparison of ventilatory pressure curves. J Trauma 1989;29:1476–9.
[58] Brimacombe J, Keller C, Kunzel KH, Garber O, Boehler M, Puhringer F. Cervical spine
motion during airway management: a cinefluoroscopic study of the posteriorly de-
stabilized third cervical vertebrae in human cadavers. Anesth Analg 2000;91:1274–8.
[59] Mercer MH, Gabbott DA. The influence of neck position on ventilation using the
Combitube airway. Anaesthesia 1998;53:146–50.
[60] Urtubia RM, Aguila CM, Cumsille MA. Combitube: a study for proper use. Anesth
Analg 2000;90:958–62.
[61] Klein H, Williamson M, Sue-Ling HM, et al. Esophageal rupture associated with the use
of the Combitube. Anesth Analg 1997;85:937–9.
[62] Richards CF. Piriform sinus perforation during esophageal-tracheal Combitube
placement. J Emerg Med 1998;16:37–9.
[63] Vezina D, Lessard MR, Bussieres J, et al. Complications associated with the use of the
esophageal-tracheal Combitube. Can J Anesth 1998;45:823–4.
[64] Yamamura H, Yamamoto T, Kamiyama M. Device for blind nasal intubation.
Anesthesiology 1959;20:221.
[65] Hung OR, Pytka S, Morris I, et al. Lightwand intubation: II. Clinical trial of a new
lightwand for tracheal intubation in patients with difficult airways. Can J Anaesth
1995;42:826–30.
[66] Verdile VP, Heller MB, Paris PM. Nasotracheal intubation in traumatic craniofacial
dislocation: use of the lighted stylet. Am J Emerg Med 1988;6:39–41.
[67] Verdile VP, Chiang JL, Bedger R, et al. Nasotracheal intubation using a flexible lighted
stylet. Ann Emerg Med 1990;19:506–10.
[68] Ainsworth QP, Howells TH. Transilluminated tracheal intubation. Br J Anaesth 1989;
62:494–7.
[69] Hung OR, Pytka S, Morris I, et al. Clinical trial of a new lightwand device (Trachlight) to
intubate the trachea. Anesthesiology 1995;83:509–14.
[70] Hung OR, Pytka S, Murphy MF, et al. Comparative hemodynamic changes following
laryngoscopic or lightwand intubation. Anesthesiology 1993;79(Suppl 3A):A497.
[71] Knight RG, Castro T, Rastrelli AJ, et al. Arterial blood pressure and heart rate response
to lighted stylet or direct laryngoscopy for endotracheal intubation. Anesthesiology
1988;69:269–72.
[72] Weis FR. Lightwand intubation for cervical spine injuries [letter]. Anesth Analg 1992;
74:622.
[73] Hung OR, Stewart RD. Illuminating stylet (lightwand). In: Benumof JL, editor. Airway
management, principles and practice. St Louis: Mosby; 1996. p. 342–52.
[74] Macintosh RR. An aid to oral intubation. Br Med J 1949;1:28.
[75] McCarroll SM, Lamont BJ, Buckland MR, Yates AP. The gum-elastic bougie: old but
still useful. Anesthesiology 1988;68:643–4.
[76] Moscati R, Jehle D, Christiansen G, et al. Endotracheal tube introducer for failed
intubations: a variant of the gum elastic bougie. Ann Emerg Med 2000;36:52–6.
288 K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
[77] Gataure PS, Vaughan RS, Latto IP. Simulated difficult intubation: a comparison of the
gum elastic bougie and the stylet. Anaesthesia 1996;51:935–8.
[78] Nocera A. A flexible solution for emergency intubation difficulties. Ann Emerg Med
1996;27:665–7.
[79] Kidd JF, Dyson A, Latto IP. Successful difficult intubation: use of the gum elastic bougie.
Anaesthesia 1988;43:437–8.
[80] Dogra S, Falconer R, Latto IP. Successful difficult intubation: tracheal tube placement
over a gum-elastic bougie. Anaesthesia 1990;45:774–6.
[81] Groves J, Edwards N, Hood G. Difficult intubation following thoracic trauma. Anaes-
thesia 1994;49:698–9.
[82] Nolan JP, Wilson ME. Orotracheal intubation in patients with potential cervical spine
injuries: an indication for the gum elastic bougie. Anaesthesia 1993;48:630–3.
[83] Randalls B, Toomey PJ. Laryngeal oedema from a neck haematoma. Anaesthesia
1990;45:850–2.
[84] Nolan JP, Wilson ME. An evaluation of the gum elastic bougie: intubation times and
incidence of sore throat. Anaesthesia 1992;47:878–81.
[85] Kadry M, Popat M. Pharyngeal wall perforation—an unusual complication of blind
intubation with a gum elastic bougie. Anaesthesia 1999;54:404–5.
[86] Viswanathan S, Campbell C, Wood DG, et al. The Eschmann tracheal tube introducer
(gum elastic bougie). Anesth Rev 1992;19:29–34.
[87] Murphy MF, Hung OR. Blind digital intubation. In: Benumof JL, editor. Airway
management, principles and practice. St Louis: Mosby; 1996. p. 277–81.
[88] Stewart RD. Digital intubation. In: Dailey RH, Simon B, Stewart RD, et al, editors. The
airway: emergency management. St Louis: Mosby; 1992.
[89] Korber TE, Henneman PL. Digital nasotracheal intubation. J Emerg Med 1989;7:275–7.
[90] Woody NC, Woody HG. Direct digital intratracheal intubation for neonatal re-
suscitation. J Pediatr 1968;73:903–5.
[91] Butler FS, Cirillo AA. Retrograde tracheal intubation. Anesth Analg 1960;39:333.
[92] Bourke D, Levesque PR. Modification of retrograde guide for endotracheal intubation.
Anesth Analg 1974;53:1013–4.
[93] Benumof JL. Management of the difficult airway. Anesthesiology 1991;75:1087–110.
[94] Gupta B, McDonald JS, Brooks HJ, Mendenhall J. Oral fiberoptic intubation over
a retrograde guidewire. Anesth Analg 1989;68:517–9.
[95] Barriot P, Riou B. Retrograde technique for tracheal intubation in trauma patients. Crit
Care Med 1988;16:712–3.
[96] McNamara RM. Retrograde intubation of the trachea. Ann Emerg Med 1987;16:680–2.
[97] Sanchez A, Pallares V. Retrograde intubation technique. In: Benumof JL, editor. Airway
management, principles and practice. StLouis: Mosby; 1996. p. 320–41.
[98] Audenaert SM, Montgomery CL, Stone B. Retrograde-assisted fiberoptic tracheal
intubation in children with difficult airways. Anesth Analg 1991;73:660–4.
[99] Benumof JL. Transtracheal jet ventilation via percutaneous catheter and high-pressure
source. In: Benumof JL, editor. Airway management, principles and practice. St Louis:
Mosby; 1996. p. 455–74.
[100] O’Sullivan TJ, Healy GB. Complications of venturi jet ventilation during microlaryngeal
surgery. Arch Otolaryngol Head Neck Surg 1985;111:127–31.
[101] Poon YK. Case history number 89: a life threatening complication of cricothyroid
membrane puncture. Anesth Analg 1976;55:298–301.
[102] Smith RB, Babinski M, Klain M, et al. Percutaneous transtracheal ventilation. J Amer
Coll Emerg Physicians 1976;10:765–70.
[103] Smith RB, Schaer WB, Pfaeffle H. Percutaneous transtracheal ventilation for anesthesia:
a review and report of complications. Can J Anesth 1975;22:607–12.
289K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259–289
	Management of the difficult airway: alternative airway techniques and adjuncts
	Prediction of the difficult airway
	Preparation
	Prehospital intervention
	Initial evaluation
	Aids to ventilation
	The laryngeal mask airway
	Insertion technique
	Indications and advantages
	Contraindications and disadvantages
	The intubating LMA
	Insertion technique
	Indications and advantages
	Fiberoptic intubation
	Insertion technique
	Indications and advantages
	Contraindications and disadvantages
	Combitube
	Insertion technique
	Indications and advantages
	Contraindications and disadvantages
	Lighted stylet
	Insertion technique
	Indications and advantages
	Contraindications and disadvantages
	Gum elastic bougie
	Insertion technique
	Indications and advantages
	Contraindications and disadvantages
	Digital intubation
	Technique
	Indications and advantages
	Contraindications and disadvantages
	Retrograde intubation
	Technique
	Indications and advantages
	Contraindications and disadvantages
	Jet ventilation
	Technique
	Indications and advantages
	Contraindications and disadvantages
	Summary
	Acknowledgment
	References