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Emergency airway management
Michele Blanda, MD, FACEP*,
Ugo E. Gallo, MD, FACEP
Northeastern Ohio Universities College of Medicine and Summa Health System,
41 Arch Street, Room 519, Akron, OH 44304, USA
Emergency airway management is one of the most crucial aspects in
caring for critically ill patients. The patient’s rapidly evolving condition as
well as the spectrum of acute airway disorders confronted in an emergency
setting requires both knowledge and skill in all aspects of acute airway
management. The need for intubation can be determined by assessing
the integrity of the airway, the adequacy of oxygenation and ventilation, the
ability to protect the airway, and the need for intubation based on the
patient’s present condition or therapy required. This determination is dy-
namic; the emergency physician should consider the need for intubation
not only at the time of presentation but also in the management of the
patient’s condition. Endotracheal intubation is used to establish, maintain,
or protect an airway that is compromised or has a potential for compro-
mise. In addition, it is used to improve pulmonary toilet and to enhance
oxygenation and ventilation. It is the first choice for invasive airway
management when simple positioning or bag valve mask ventilation is
inadequate. Consideration of the patient’s airway in this context allows the
emergency physician to anticipate and prepare for the difficult airway, thus
avoiding a potential forced and hurried intubation.
A standard definition for the difficult airway has not been identified. In
this article, a difficult airway is defined as a clinical situation in which the
practitioner experiences difficulty with ventilation, laryngoscopy, or tracheal
intubation. There is strong evidence that specific strategies facilitate man-
agement of the difficult airway. Although the exact degree of benefit cannot
be determined, there is strong agreement that a preformulated strategy will
lead to improved outcomes [1–4]. The strategy will depend in part upon the
patient’s condition and the physician’s skills and preferences.
Emerg Med Clin N Am
21 (2003) 1–26
* Corresponding author. Department of Emergency Medicine, Summa Health System,
41 Arch Street, Room 519, Akron, OH 44304.
E-mail address: blandam@summa-health.org (M. Blanda).
0733-8627/03/$ - see front matter � 2003, Elsevier Science (USA). All rights reserved.
doi:10.1016/S0733-8627(02)00089-5
This article assumes the reader is knowledgeable and experienced in
routine endotracheal intubation techniques. It focuses on identification
and management of the difficult airway, including alternative noninvasive
techniques such as tactile intubation, directional tubes, stylets, combination
tubes, and the laryngeal mask airway. Invasive techniques discussed are
retrograde intubation, needle cricothyrotomy, and surgical cricothyrotomy.
Methods for intubation such as rapid sequence intubation and awake
intubation techniques are also reviewed.
Difficult intubations
The experienced clinician can usually anticipate when intubation may be
difficult (Box 1) [5]. This is determined by obtaining a directed airway
history and thorough physical exam. In many cases history and physical
examination may be abbreviated because of emergent circumstances, but
they should not be omitted. This assessment is a reliable indicator of the
patient’s overall state of health and is useful in predicting potential dif-
ficulties [3,5–7]. Occasionally, despite a thorough evaluation, a patient may
present with an unexpected problem during intubation. At these times the
practitioner should depend on a preformulated plan of action.
History
The historical data obtained should be brief and include information
about previous intubations with delineation of any problems, the presence
of dental appliances (bridges, fillings) or loose teeth, and the time of last
meal, because this may influence the choice of pretreatment and paralysis
medications.
Medical disease history should be directed to determine if there is
congenital or acquired disease that may interfere with the mobility of the
cervical spine, atlanto-occipital joint, mandible, or soft tissues of the oral
cavity and neck; such diseases include arthritis (especially rheumatoid) and
ankylosing spondylitis. If nasotracheal intubation is contemplated, inquiries
about clotting disturbances, nasal polyps, and a history of epistaxis should
be obtained.
Physical exam
A general assessment of the patient’s overall condition, especially the level
of consciousness and the ability to breathe should be performed. Examination
of the airway includes exam of the temporomandibular joint (TMJ),
mandible, lips oral cavity, tongue, teeth, neck, and cervical spine. The nose,
septum, and nasal pharynx should be included if nasotracheal intubation is
being used or considered as a rescue technique in the breathing patient.
2 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
The function of the TMJ is complex and involves articulation and
movement between the mandible and the cranium. There are two distinct
movements involved in opening the mouth, and each contributes ap-
proximately 50% to the degree of opening of the mouth [8]. The first is a
hinge-like movement of the condyle through the synovial cavity, and the
second is the forward displacement of the condyle.
Assessment of the TMJ is performed by having the patient open their
mouth widely (Fig. 1). The practitioner should listen and palpate for clicks
and crepitus, both of which indicate joint dysfunction, and assess the width
of the opening. Normal adults are capable of inserting three fingers, held
Box 1. Predisposing factors for difficult intubation
Anatomic variations
Short, thick mandible
Thick/fat ‘‘bull’’ neck
Narrow mouth opening
Large tongue
Dental anomalies/protruding teeth
Limited range of motion of cervical spine
Congenital abnormalities
Scoliosis
Mandibular hypoplasia
Maxillary hypoplasia
Klipper-Feil syndrome (decreased number of cervical
vertebrae)
Cleft lip/palate
Disease states
Temporomandibular joint disorder
Degenerative cervical spine disease/arthritis
Ankylosing spondylitis
Infection (retropharyngeal abscess, Ludwig’s angina)
Airway edema
Foreign objects
Malignancy
Previous tracheostomy
Trauma
Facial
Mandibular
Maxillary
Cervical
3M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
vertically in the midline into their mouth, which corresponds to a maximum
mandibular opening of 50 to 60 mm [9]. This width is important because
the depth of the McIntosh #3 laryngoscope blade (Hospital Equipments
Manufacturing Company, New Delhi, India) is 20 mm. If the mandibular
opening is less than this, the McIntosh #3 laryngoscope blade cannot be
inserted into the mouth, necessitating a technique different than orotracheal
intubation.
Mandible hypoplasia is frequently associated with difficult intubation.
In a normal adult, the distance from the hyoid bone to the mandibular
symphysis is about three finger widths. If this measurement is two finger
widths or less, the mandible is considered hypoplastic.
The patient’s oral hygiene should be assessed; if dentures are present,
they should be removed. In the pediatric population, an occasional foreign
object such as candy or chewing gum may be hidden in the recesses of the
oral cavity. Cleft lip deformities may present problems during intubation
because the laryngoscope blade tends to enter the cleft. Long, protruding
teeth may limit the size of the mouth opening and may be damaged during
intubation.
Two features of the tongue that may impede the clinician’s ability to see
the airway are size and mobility. Occasionally, the tongue may be so large
that it obstructs the view of the uvula, the pillars, and even the soft palate.
The Mallampati classification is commonly used in anesthesia to describe
the oral opening (Fig. 2) [6]. If the tongue is fixed in a position by tumor or
other disease state, the view of the airway may be compromised.
The neck andcervical spine should be examined before intubation. In the
traumatic patient, one should presume there is a cervical spine injury when
attempting intubation. In the atraumatic patient, the general contour of the
neck should be inspected. Obese patients with short, muscular, thick necks
Fig. 1. Temporomandibular joint assessment.
4 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
typically have a limited range of motion and are more difficult to intubate.
Skin pigmentation changes may be secondary to recent radiotherapy, which
can cause acute inflammatory changes, scarring, and fibrosis in the neck
region. Previous tracheostomy scars suggest tracheal stenosis and diffi-
cult intubation. All neck masses warrant concern, especially if related to a
vascular injury, since the airway can be occluded without warning. Infec-
tions such as a retropharyngeal abscess, or Ludwig’s angina can distort the
anatomy to such a degree that there is soft tissue displacement of the trachea.
Vocal quality and the presence of stridor also suggest airway com-
promise. Lesions that are predominantly supraglottic are typically asso-
ciated with inspiratory stridor, whereas subglottic lesions tend to cause both
inspiratory and expiratory stridor.
Fig. 2. Mallampati classification to describe oral opening. (From McGill JW, Clinton JE.
Tracheal intubation. In: Roberts JR, Hedges JR, editors. Clinical procedures in emergency
medicine. 3rd Edition. Philadelphia: WB Saunders; 1998. p. 15–44.)
5M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
Mobility of the cervical spine is measured by flexion or extension. The
optimal position for endotracheal intubation is flexion of the cervical spine
and extension of the head at the atlanto-occipital joint. Flexion or extension
deformities of the cervical spine associated with arthritides can make direct
laryngoscopy more difficult, if not impossible.
Suboptimal standard technique can also make a routine intubation
difficult [10]. The most common mistake made during intubation is
‘‘cranking back’’ on the laryngoscope handle to lever the top of the blade
to provide better visibility. This maneuver may improve glottic visual-
ization, however, it restricts the intubators’ ability to manipulate the tube by
limiting the size of the oral opening and it jeopardizes the teeth. During
direct laryngoscopy, damage to the teeth is usually caused by excessive
pressure on the teeth. Lifting the laryngoscope and blade upward and
forward both improves the glottic visibility and increases the oral opening,
allowing more room for manipulating the endotracheal tube.
Alternative noninvasive techniques
Several modifications of the standard technique, as well as adjuncts and
alternative techniques, have been reported to assist in difficult intubations
(Box 2) [11,12]. Changing the laryngoscope blade from curved to straight or
vice versa is a simple technique that may favorably affect the intubators’
ability to see the glottis or manipulate the tube successfully. Straight (Miller)
blades (Hospital Equipments Manufacturing Company, New Delhi, India)
are narrow blades with a curved central canal. A patient may be easier to
intubate with a straight blade if they have overriding teeth, a very floppy
epiglottis, or a thick neck that is difficult to maneuver. Straight blades are
better for intubating small children. The curved (McIntosh) blade has a
broad, flat surface and a tall flange to enhance movement of the tongue.
For adults, a McIntosh #3 or #4 or a Miller #2 blade is most useful.
Occasionally a patient with a thick neck will require a Miller #3.
Position of the patient is a simple maneuver that may aid visualization of
the vocal cords. To establish this line of sight, there are three axis that must
be obtained (Fig. 3) [13]. The first is the axis of the mouth to the posterior
pharynx, the second is a line running parallel to the posterior pharynx, and
third is the line of the larynx as it traverses into the trachea. At rest, none of
these axes are completely aligned. To establish a clear line of sight, it is
important to first flex the neck on the shoulders to align the posterior
pharynx and the larynx. Approximately 30� of flexion is necessary to achieve
this alignment. It is useful to place towels or folded sheets under the occiput
of the patient to assist in holding this position. Next, it is important to
extend the head on the neck to approximate a line of sight from the mouth,
with the line of the pharynx and with the now aligned larynx. This requires
approximately 20� of extension, although more may be necessary depending
on the soft tissue of the posterior pharynx. This extension occurs at the
6 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
atlanto-occipital joint and thus, the cause of difficulty if there is arthritis or
cervical spine abnormalities. This final alignment is conducive to direct
visualization of the vocal cords and is called the ‘‘intubating’’ or ‘‘sniffing’’
position.
Digital/tactile intubation
During laryngoscopy, the only structure commonly seen is the epiglottis.
A blind technique using anatomical landmarks is the digital or tactile
technique. The endotracheal tube is passed blindly by sliding the end of
the tube along the under surface of the epiglottis and through the glottic
opening [13,14]. By palpating the epiglottis with the index and long fingers,
the epiglottis can be picked up by the long finger and directed anteriorly.
The tube is guided by the index finger under the epiglottis and into the
Box 2. Invasive and noninvasive alternatives, modifications,
and adjuncts
Invasive techniques
Translaryngeal guided or ‘‘retrograde’’ intubation
Fiberoptic endotracheal intubation
Percutaneous transtracheal ventilation or needle
cricothyrotomy
Surgical cricothyrotomy
Percutaneous tracheostomy
Surgical tracheostomy
Noninvasive techniques
Changing laryngoscope blades
Endotracheal tube stylet
Magill forceps
Directional tip control tubes
Blind orotracheal passage based on landmarks
Use of an assistant
Special laryngoscope blades
Guiding stylets
Lighted stylets
Tactile orotracheal intubation
Pharyngeotracheal lumen airway
Esophageal–tracheal combitube airway
Laryngeal mask airway
Standard nasotracheal intubation
Tactile nasotracheal intubation
7M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
trachea. A stylet bent at a 90� angle 4 to 6 cm from the tip of the tube should
be used to assist in placement.
Advantages of ‘‘tactile intubation’’ include rapidity (when experienced),
no need for special equipment and no movement of the head and neck. The
limitation to this technique is to be successful the patient must be deeply
unconscious or there may be injury to the intubator’s hand.
Fig. 3. Head tilt axes. (From McGill JW, Clinton JE. Tracheal intubation. In: Roberts JR,
Hedges JR, editors. Clinical procedures in emergency medicine. 3rd Edition. Philadelphia: WB
Saunders; 1998. p. 15–44.)
8 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
Directional tubes
Endotracheal tubes (Endotrol tubes�, Mallinckrodt, Hazelwood, MD)
with directional tip controls allow the intubator to alter the distal curve of
the tube as needed during insertion [14]. This avoids intubation delays
caused by having to readjust the tube curve. Magill forceps, while designed
primarily for assisting with nasotracheal intubation, may also be useful for
directing a tube during attempted orotracheal intubation. This is a two-
person technique with an assistant used to retract the laryngoscope with the
intubators’ guidance. After adequate glottic exposure is attained by the
assistant, the intubators manipulate the tube into the glottic opening using
the Magill forceps.
Stylets
Stylets are commonly used to ensure that the tube is rigid and to allow
greater curvature of the tube for reaching the more ‘‘anteriorly’’ situated
larynx. The rigid stylet should never extend beyond the tip of the tube
because it may cause pharyngeal or laryngeal trauma.Passing a smaller
guide through the glottis initially may facilitate tube insertion in cases where
the glottic opening can be seen but endotracheal tube insertion is difficult
(eg, glottic edema in a burn patient). Devices successfully used for this
purpose include suction catheters or tracheal tube exchangers over stylet
wires. In addition, there are specially designed stylets with distal directional
control that assist in moving the tube into the tracheal opening.
Lighted stylets
A transillumination technique for blind orotracheal or nasotracheal
intubation is the lighted stylet or ‘‘light wand’’ [15–18]. The light at the tip
of the stylet is positioned within 0.5 cm of the end of the endotracheal tube.
Using a 90� angle placed 4 to 6 cm from the end of the tube, the tube is guided
by observing the anterior neck for transillumination through the soft tissue. A
bright red glow in the midline at the level of the larynx indicates proper
guidance of the tube. (Fig. 4) The tip of the tube is in the pyriform sinus if the
bright red glow is off themidline. A dull diffuse glow represents passage of the
Fig. 4. Lighted stylet tube placement.
9M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
tube into the esophagus.An advantage of this technique is the lack of head and
neck manipulation. This technique is limited by overhead lighting, which
creates difficulty seeing the stylet light. Also, because it is a blind technique, it
is not recommended in patients with anatomic abnormalities of the upper
airway such as tumors, polyps and infections (epiglottitis).
Esophageal–tracheal tubes
Initially designed for prehospital care, these airways may provide
adequate ventilation as a temporizing measure until a more secure airway
can be obtained [19–21]. These combination tubes are currently part of the
ASA recommendation for a patient that cannot be intubated or ventilated.
Esophageal obturator airway (EOA) tubes had been widely used by pre-
hospital emergency medical personnel before the development of com-
bination tubes. The EOA’s major limitation was that ventilation was
impossible if there was tracheal placement.
The Combitube (The Kendall Company, Mansfield, MA) is currently the
more commonly used tube (Fig. 5). This airway device is a double lumen
ventilation tube with two cuffs, a small distal cuff and a larger proximal
cuff. One tube has a sealed distal end with perforations located on the sides
between the cuffs. The other tube has an open distal end. If the tube passes
blindly into the trachea, the tube with the open distal lumen is used for
Fig. 5A. Esophageal and tracheal Combitube placement. For esophageal placement: (1) the
blue port connects with fenestrations to indirectly ventilate the lungs; (2) ventilations through
the blue port exit the Combitube through fenestrations just above the trachea; (3) the large latex
cuff seals the pharynx and prevents ventilations from exiting; (4) the distal end of the
Combitube has an opening, but is not used.
10 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
ventilation as an endotracheal tube. If the tube passes into the esophagus,
the shorter tube is used to ventilate the lungs similar to the EOA.
The advantage of this device is that it avoids the problem of accidental
tracheal intubation and no ability to ventilate that may occur with an EOA.
It may be helpful if there is massive bleeding or regurgitation. It requires no
head or neck movement and can be used on cervical spine injury patients.
The disadvantage is a contraindication in patients under 16 years of age or
less than 150 inches tall. The Combitube must be used in patients without
an intact gag who are unconscious. Combination tubes are an accepted
alternative for rescue airway but are most often seen in patients from the
field. Familiarity with these devices is important to ensure proper use.
Laryngeal mask airway
The laryngeal mask airway (LMA) was approved for use in the United
States in 1992. It was developed in the 1980s and was used in the United
Kingdom in the latter portion of that decade. It serves as a bridge between
endotracheal intubation and face mask ventilation [22]. This device consists
of a tube resembling an endotracheal tube with a distal mask structure
designed to form a seal around the glottic structures in the hypopharynx. It
is placed in unconscious patients and traditionally has been used on patients
under anesthesia. A blind technique is used to place the LMA using the
thumb and index finger to advance the tube and mask horizontally over the
hard palate until it reaches into the posterior pharynx. Here the mask moves
vertically until resistance is met. The cuff is then inflated and breathing is
assessed by normal excursion, breath sounds, and no evidence of extraneous
Fig. 5B. For tracheal placement: (A) the clear port connects with the distal lumen and provides
direct ventilation; (B) the distal end of the Combitube has an opening.
11M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
sounds. Slow, controlled breaths work best to avoid leakage around the cuff
and the appearance of ineffective placement and unnecessary removal.
The LMA comes in multiple sizes ranging from 1 to 5. Sizes 1 and 2 (with
half sizes) are recommended for children, Generally size 4 is used for
normal-sized adults and size 5 is used for adults weighing more than 70 kg.
Both a disposable and reusable LMA are available. In addition, an intu-
bating LMA permits intubation through the device itself using a specifically
designed endotracheal (ET) tube.
The LMA is an excellent replacement for face mask ventilation. It does
not replace the endotracheal tube largely because of the risk of aspiration.
In addition, laryngospasm and inability to ventilate can still occur [23].
Inability to ventilate can occur because of glottic rigidity or any soft tissue
obstruction above the level of the glottis. Experience with this device in
emergency airway situations is limited at present, but it may offer another
temporary measure until a more secure airway can be obtained.
Nasotracheal intubation
Awake, blind nasotracheal intubation is different from endotracheal
intubation because it requires a breathing patient. The nasal procedure is
somewhat more difficult, is more time-consuming, and has a lower success
rate than the orotracheal route [24,25].
Indications for nasotracheal intubation include dyspneic patients in
whom the supine position is impossible or contraindicated and in whom the
oral cavity is not accessible to orotracheal intubation. Examples of this
are wired jaws, anatomical problems (eg, a small mouth), TMJ arthritis,
trismus, tetanus, intraoral infections, active seizures, obstructing lesions of
the anterior oropharynx (eg, tumors), Ludwig’s angina, lingular swelling/
hematoma, or dental abscesses. Other indications are unsuccessful oro-
tracheal intubation despite multiple attempts or patients in whom para-
lyzing agents are contraindicated.
The tube for nasotracheal intubation should be approximately 1 mm
smaller in diameter than the tube used for orotracheal intubation. It should
be made of clear polyvinylchloride to allow breath condensation to be seen
on the inside walls of the tube. Directional tubes are preferred.
There are three anesthetic techniques that may be helpful in nasotracheal
intubation: nasal, pharyngeal and translaryngeal. Nasal anesthesia is ob-
tained using either topical viscous lidocaine (2% to 4%) and phenylephrine
(1%) or cetacaine solution and phenylephrine (1%) or cocaine solution 2% to
10% [26]. One to two milliliters of solution in each nares should be sufficient
and can be applied with cotton swabs, pledgets, or spray. These combinations
allow both anesthesia and vasoconstriction. Cocaine is the only topical
anesthetic agent that provides both vasoconstriction and anesthesia.
Lidocaine and cetacaine anesthesia require approximately 60 seconds for
onset, whereas cocaine takes 5 minutes [25]. Hypertension is a relativecontraindication to the use of both cocaine and phenylephrine [27].
12 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
Pharyngeal anesthesia is performed by spraying lidocaine or cetacaine to
the posterior pharynx. It is controversial whether pharyngeal anesthesia
predisposes patients to aspiration [28]. Translaryngeal anesthesia is not
generally used in emergency medicine because it is unnecessary, time-
consuming, and has complications [28].
Blind nasotracheal intubation is performed with the patient supine or
sitting in the ‘‘sniffing’’ position. The patient, if conscious, should receive
step-by-step instructions before and during the procedure. Lack of proper
psychological preparation will lead to fear, anxiety, movement, and lack of
cooperation. The edge of the tube is placed against the nasal septum of the
chosen nostril, to prevent abrasions and bleeding, and the tube is directed
perpendicular to the facial plane with the curvature of the tube facing
superiorly. The tube is then inserted through the nasal passage and into the
pharynx by using a continuous forward pressure. If difficulty with passage
occurs, one can try a smaller tube or use the other nostril. Once the tube
is in the pharynx, it should be rotated 180� so that the curvature faces
inferiorly. The tube now serves as a nasal airway and facilitates the re-
mainder of the procedure. If the tube impedes on the posterior pharyngeal
wall, redirection by traction on the ring of the directional tube will over-
come this obstacle.
Upon advancing the tube forward approximately 2.5 to 5.0 cm, the
operator will note air movement passing through the tube. As the intubator
appreciates airflow, an assistant should apply gentle but firm pressure on the
cricoid cartilage (the Selek maneuver). The patient should be instructed to
breathe in and out, and during inspiration the tube is advanced beyond the
vocal cords. Balloon inflation and tube confirmation is performed using
standard techniques.
The nasotracheal tube can lie in only one of five locations outside the
trachea: (1) the vocal cords outside the larynx, (2) the vallecula, (3) the left
pyriform fossa, (4) the right pyriform fossa, or (5) the esophagus. A
misdirected tube at the vocal cords outside the larynx results in obstruction
to passage of the tube despite good detection of breath sounds and can be
corrected by gentle rotation. A tube that impacts the vallecula will often
cause a midline supralaryngeal bulge in the neck. Retracting the tube a few
centimeters, followed by gentle pressure in the area just above the larynx, or
by slight flexion of the head, will solve this problem. Misdirection of the
tube into either the left or right pyriform fossae will often result in a
corresponding lateral bulge in the neck. This problem is corrected by (1)
displacing the patient’s larynx slightly in the direction of the bulge, (2)
rotating the tube, (3) moving the head toward the side of the displacement,
or (4) by any combination of these maneuvers.
There is debate concerning the desirability of oral versus nasotrachea
intubation for patients in whom a prolonged intubation is expected.
Nasal airways are better tolerated by patients, but they carry the risk of
turbinate necrosis and sinusitis with prolonged use [24]. Relative
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contraindications to performance of nasotracheal intubation include
severe nasal or oral hematomas or hemorrhage, infections or hemato-
mas of the upper neck, maxillary facial trauma, blood clotting abnor-
malities, nasopharyngeal obstruction (deviated septum, masses) and acute
epiglottitis.
Apnea or near apnea is an absolute contraindication only in use of
the standard blind technique. However, use of the lighted stylet fiberoptic
endoscope, or tactile technique has been reported to aid in nasotracheal
intubation in the apneic patient [26,29–31]. This technique has not been
reported outside the anesthesia literature. Also, even with vasoconstriction
and gentle tube manipulation, problematic epistaxis can occur [24,32,33].
Invasive airway management
Translaryngeal guided (‘‘retrograde’’) intubation
Retrograde tracheal intubation is an effective emergency technique for
securing an airway should conventional means of endotracheal intubation
fail. Nevertheless, this technique has not yet gained wide clinical acceptance.
This may be because of its invasive nature and the potential difficulty
associated with cricothyroid puncture; in addition, it is rarely taught in the
clinical setting [34]. Retrotracheal intubation requires minimal operator
experience and can be performed without head or neck movement [35,36].
Use of retrograde intubation is indicated in a clinical setting in which an
alternative technique is desired because of bleeding, secretions, or vomitus in
the upper airway that obscures glottic visualization and there is inability
to orally or nasally intubate using standard techniques. It is an alterna-
tive to surgical cricothyrotomy [34,35,37]. Stable, cooperative patients, and
comatose patients with free access to the posterior pharynx and spontaneous
respiratory efforts are the most suitable candidates. Retrograde tracheal
intubation may not be suitable for patients requiring immediate intubation
and ventilation, since the procedure can be expected to take up to 5 minutes
for completion [38].
Cases have been reported in which retrograde intubation has proved
effective in patients with abnormal anatomical or pathologic conditions
of the upper airway, including congenital orofacial lesions, tumors, and
infections such as acute epiglottitis. Retrograde tracheal intubation has also
been useful in patients with other conditions limiting visualization of the
glottis such as cervical spondylosis, trauma, or severe kyphosis. Patients
sustaining severe orofacial trauma, in whom distortion of normal anatomy
and a blood field precludes convention endotracheal intubation, are con-
sidered candidates as well [39–42].
Preparation for retrograde intubation includes preoxygenation and local
anesthesia. Oxygen should be provided through a face mask. Use of retro-
grade tracheal intubation allows unimpeded upper airway management
up to the point of retrieval of the guide catheter/wire from the posterior
14 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
pharynx. Bag mask ventilation may also be added if spontaneous respi-
rations are deemed inadequate
After preoxygenation of the patient and equipment preparation, the
posterior pharynx is sprayed with a topical anesthetic. A sterile technique is
advisable if time permits. One milliliter of 1% lidocaine is injected into the
skin overlying the cricothyroid membrane, and another 2 ml is injected into
the glottic space and supraglottic lumen. In the conscious patient, care
should be taken to remove the needle quickly after this maneuver to avoid
injury from subsequent coughing.
Retrograde intubation is performed using a 16- to 18-gauge needle placed
in the cricothyroid membrane, directing the needle at 30� to 40� angle
cephalad. When positioning the needle, it should be connected to a syringe
filled with saline, and the bevel of the needle should be aligned with the scale
marked on the barrel of the syringe. This allows direction of the bevel
cephalad once inside the larynx. The syringe can then be aspirated as it is
being inserted to ensure that the needle tip has entered the laryngotracheal
lumen (Fig. 6). A small stab incision with a #11 surgical blade may facilitate
entrance of the needle to the skin.
A through-the-needle catheter or, preferably, a soft-tipped guide wire is
then passed retrograde from the larynx to the oral cavity where it is
retrieved. The guide wire needs to be long enough to pass out of the mouth.
A 100-cm wire is recommended to allow manipulation of the tube or use of
adjunct equipment. The needle is removed and the guide wire is secured at
the skin over the cricothyroid membrane with a hemostat.
The endotrachealtube is placed over the guide wire at the proximal end
of the wire (near the oral cavity). The wire is threaded into the distal side
hole (Murphy’s eye) and out the proximal end of the tube (Fig. 7) [43]. The
tube is then passed along the guide wire into the larynx while the guide is
held taut. Mild to moderate pressure must be held on the ET tube to
advance it into the trachea. The wire is withdrawn from the mouth in a
retrograde direction to prevent contamination of cervical soft tissues at the
Fig. 6. Confirmation of placement in the laryngotracheal lumen.
15M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
puncture site. It is important that the motion of pulling the wire and the
advancement of the tube occur simultaneously; in addition, this maneuver
requires both hands and pressure. This is to ensure that when the guide is
released the tube will move down through the larynx and into the trachea
and not fall back into the hypopharynx. The advancing beveled edge of the
endotracheal tube may strike against the vocal cords; if this occurs, use of
force to move the tube through the glottis must be avoided. Rather, use
simple counterclockwise rotation of the endotracheal tube 90� to bring
Murphy’s eye anterior and align the bevel perpendicular to the glottis slits,
which allows the tube to pass [40].
Modifications of this technique have been described using a plastic sheath
protector, a Cook exchange catheter, or a flexible stylet through the ET tube
into the distal trachea just before releasing the guide wire [34]. This may help
prevent the ET tube from falling back into the hypopharynx.
An absolute contraindication to this procedure is complete upper airway
obstruction. Other relative contraindications include severe trauma to the
larynx or laryngotracheal separation, the presence of an enlarged thyroid
gland, soft tissue infection or abscess over the cricothyroid area, co-
agulopathy, and inability to open the mouth for catheter retrieval. The
major limitation of this technique is that if the endotracheal tube falls into
the hypopharynx at guide release, the procedure must be repeated.
Percutaneous transtracheal ventilation or needle cricothyrotomy
Percutaneous transtracheal ventilation or needle cricothyrotomy can be
used as a temporizing measure when oral or nasal intubation is not possible.
It is not recommended if there is complete airway obstruction, although this
has been recently debated if a large catheter is used.
The technique is similar to the retrograde technique. The cricothyroid
membrane is identified, and a 12- to 16-gauge over-the-needle catheter that
Fig. 7. Endotracheal tube guidewire threading.
16 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
is attached to a saline-filled syringe is inserted at a 30� to 45� angle caudally.
Unlike the retrograde technique, it is not directed toward the head because
no wire has to be directed to the oral cavity. The catheter is threaded into
the hub. The catheter tip is then connected to a pressurized oxygen ap-
paratus capable of delivering approximately 50 psi of oxygen. One-second
inflations are provided at a rate of approximately 12 per minute. If a high-
pressure oxygen source is not available, another alternative is to attempt
to use a bag-valve apparatus connected to the catheter. The proximal con-
nector of an 8.0 ET tube will fit tightly inside a 3-cc syringe, which could be
connected to the catheter. In addition, the proximal connector of a 3.0 ET
tube will fit into a catheter hub.
An alternative to this technique is to use a Seldinger catheter introducer
set, such as an 8.5-Fr introducer kit commonly used for pulmonary artery
catheters. The needle can be used to make the initial puncture and the
guidewire inserted securely into the distal trachea. The catheter is then
inserted over the wire using the dilator. The 8.5-Fr catheters have been
shown to provide some exhalation and have been used successfully in
models of complete airway obstruction.
It is most important to remember that this is a temporary procedure until
a more secure airway can be attained. In addition, its effect is limited
because oxygenation can only be maintained for about 30 minutes because
of the lack of adequate ventilation and progressive hypercapnia.
Surgical cricothyrotomy
There are few situations in emergency medicine that inspire more concern
than an airway that needs to be managed surgically. The incidence is low and
the acquisition of the necessary skill is difficult. Even when a clinical situation
requires a surgical airway, there is often a psychological reluctance to
attempt the procedure. This tends to make the procedure even more diffi-
cult because delay only places greater time constraints on the emergency
physician to achieve a successful airway. The only mandatory indication for
a surgical airway is total upper airway obstruction. The most common
reason is failure to achieve intubation by nonsurgical means. The emergency
physician is usually more familiar and comfortable with alternative forms of
airway management, and often persists in attempts to achieve oral or nasal
intubation, when in fact the patient needs a surgical airway.
Surgical cricothyrotomy is indicated in the setting of severe maxillofacial
trauma preventing oral intubation, known unstable cervical spine fracture,
laryngotracheal trauma except for tracheal transection, complete upper
airway obstruction oropharyngeal obstruction or inability to secure the
airway by other intubation techniques. It is contraindicated in pediatric pa-
tients less than 12 years old or if there is laryngotracheal separation or
tracheal transection. The latter contraindication is because the transected
airway may be tenuously held together by the cervical fascia. An incision
dividing the fascia will cause the distal stump of the trachea to retract into
17M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
the mediastinum with disastrous consequences for the patient. If an
endotracheal tube cannot be passed across the separation to act as a stent,
a tracheostomy is the preferred surgical approach. Penetrating trauma to
the neck in either high Zone 2 or Zone 3 associated with an expanding
hematoma is also a contraindication.
Surgical cricothyroidotomy is performed by first locating the cricothyroid
membrane. The easiest way to remember this technique is to break it into
four steps: palpation, incision, insertion and intubation. The larynx is
palpated and stabilized by bracing the laryngeal cartilage with the thumb
and middle finger. The position of the cricothyroid membrane is maintained
with the index finger (Fig. 8). A skin incision is then made and can be
a midline, vertical incision (3–4 cm) or a horizontal incision over the cri-
cothyroid membrane. An incision is then made through the cricothyroid
membrane just above the cricoid cartilage. A Trousseau dilator, tracheal
hook, hemostat, or blade handle should be immediately inserted in the
opening. A tracheostomy tube (a #4 is appropriate for an average adult) or
an endotracheal tube (6.0 mm is adequate for an average adult) should be
inserted to secure the airway. It is very important not to lose control of the
opening that has been made.
A rapid, four-step cricothyrotomy technique has been described in the
literature [44]. In this technique, the skin incision is made horizontally at
the same time the incision is made through the cricoid membrane. This
technique, however, has been reported to have an increased incidence of
cricoid cartilage fracture [45].
It is important to remember that cricothyrotomy is an emergency
procedure, which is guided by palpation of the anatomy. When indicated, it
must be performed rapidly and it can usually be completed in less than 30
seconds. It is a procedure guided by touch, not sight. The time required to
dissect the neck tissues adequately to see the cricothyroid membrane would
likely require several minutes; such a time delay would almost certainly be
detrimentalto the patient.
Fig. 8. Position maintenance of cricothyroid membrane.
18 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
This technique has limitations in severe laryngotracheal trauma, cervical
hematoma, or swelling of the neck, which can make performance of it very
difficult. In addition, cricothyrotomy is useless in complete tracheal
transection or tracheal foreign body.
Rapid sequence intubation
Rapid sequence intubation (RSI) involves the use of neuromuscular
blocking agents and sedatives or hypnotic agents to facilitate intubation and
limit the potential adverse effects of laryngoscopy and intubation [34,46,47].
It also allows the patient to be intubated without experiencing the phy-
siological trauma of being intubated while conscious. Rapid sequence in-
tubations are now considered routine in most emergency departments,
accounting for 70% to 84% of all emergency department intubations [4,48].
The use of pharmacologic agents to assist intubations seems to decrease
complications. Comparisons of paralytic assisted and nonparalytic assisted
intubations, using historical controls, showed that non-RSI patients had
15% more aspirations, 25% more airway trauma, and 3% more deaths [49].
RSI is not a ‘‘one method fits all’’ technique. Drugs selected to be used
for RSI should be tailored to the specific scenario and the individual patient.
The clinician should be familiar with an array of pharmacological options
for emergent endotracheal intubation, including barbiturates, nonbarbitu-
rate hypnotics, benzodiazepines, opiates, associative agents, and neuro-
muscular blocking agents (Table 1). Each scenario should be evaluated to
find out if there are any relative contraindications to RSI. The major risk of
RSI is that the physician could potentially paralyze a nonapneic patient,
making it impossible to intubate, ventilate, or create a surgical airway.
The emergency physician may choose to perform an awake intubation in
certain circumstances. This option is easily employed in patients who are
spontaneously breathing but have strong contraindications to paralysis.
These include patients with any anatomical barriers that may obstruct the
airway and prevent intubation. Patients who are candidates for awake in-
tubation may receive nebulized 4% lidocaine to reduce their gag reflex, light
sedation with midazolam, or other appropriate sedating/hypnotic agents
[50,51].
Approach to RSI
RSI can be divided into five stages: preparation, preoxygenation,
premedication with sedation and anesthesia, paralysis, and intubation.
Preparation
Preparation includes appropriate placement of intravenous lines, con-
tinuous cardiac and pulse oximetry monitoring, and preoxygenation. Cardiac
monitoring is important because the procedure itself may cause cardiac
19M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
T
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20 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
dysrhythmias [52]. Pulse oximetry alerts the intubator if the patient is
becoming hypoxic. Studies have shown that pulse oximetry can reduce the
frequency and duration of hypoxemia associated with clinical intubation [53].
Preoxygenation
Preoxygenation begins with administration of high-flow oxygen to maxi-
mize arterial oxygenation. The goal is to avoid using positive pressure ventila-
tion to prevent hyperinflation of the stomach, vomiting, and aspiration. Five
minutes of 100% oxygen is best; however, one study showed that eight deep
breaths over 60 seconds significantly slowed the hemoglobin desaturation
that occurs with apnea [10]. This preoxygenation phase replaces the nitrogen
reserves in the lungs with oxygen and allows 3 to 5 minutes of apnea without
serious hypoxemia in a patient with normal hemodynamics.
Premedication
Premedication using pharmacological agents can be given to facilitate
endotracheal intubation. These agents are given to prevent the patient from
experiencing the physiologic consequences of intubation, such as increases
in pulse, blood pressure, intracranial and intraocular pressure [34,54–56].
Sedative and hypnotic agents produce a continuum of physiological effects
that range from sedation to induction of anesthesia, depending on the dose
administered [51,57–61]. Numerous different agents can be successful in
various scenarios (Table 2). The author recommends that the induction
doses not be used, but that decreased doses be given and repeated to achieve
desired effects.
Intravenous lidocaine may reduce the cardiovascular response to en-
dotracheal tube placement. Studies on this topic are conflicting [46,
62,63]. Intravenous lidocaine administered 3 to 5 minutes before intuba-
tion may blunt the associated rise in intracranial pressure, though the
evidence for this is limited [64–68]. There is no evidence that lidocaine
should be given routinely for rapid sequence intubation in the emergency
department. However, it is frequently administered to patients at risk for
Table 2
Sedative scenario table
Condition Sedatives
Normotensive + euvolemia Propofol, etomidate, thiopental
› ICP and normal BP Propofol, thiopental
› ICP and fl BP Etomidate
Severe hypotension or hypovolemia Etomidate, ketamine
Status asthmaticus Ketamine, etomidate, propofol
CHF Etomidate
Status epilepticus Thiopental, propofol, midazolam
Combative patient Propofol, etomidate, thiopental
Abbreviations: BP, blood pressure; CHF, congestive heart failure; ICP, intracranial pressure.
21M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
intracranial hypertension, including those with head trauma, presumed
central nervous system bleeding, or intracranial mass lesions. No ill effects
have been reported.
Paralysis
Neuromuscular blocking agents are used to induce complete paralysis;
this relaxes the upper airway musculature and makes laryngoscopy easier.
There are two classes of neuromuscular blocking agents: depolarizing and
nondepolarizing (Table 3). Succinylcholine is the most commonly used de-
polarizing agent because of its rapid onset and short duration of action
(usually less than 10 minutes). Nondepolarizing agents competitively block
the acetylcholine receptor on the motor end plate preventing stimulation of
the skeletal muscle. Nondepolarizing agents do not produce fasciculations;
rather, they produce flaccid paralysis.
Administration of succinylcholine in patients with pseudocholinesterase
deficiencies or underlying medical problems may prolong paralysis sub-
stantially [69]. Limitations to use of succinylcholine include elevation of
intracranial pressure, elevated intragastric pressure, prolonged paralysis,
hyperkalemia in the susceptible patient, and cardiac dysrhythmias (eg, brady-
cardia and asystole) [47,70–74]. Succinylcholine commonly induces mus-
culoskeletal fasciculation. If the clinician wishes to avoid fasciculationsassociated with succinylcholine, a subparalytic dose of a nondepolarizing
agent can be administered [70,75]. Occasionally, a subparalytic dose of
a nondepolarizing agent may induce clinical paralysis with ventilatory
compromise within 2 to 3 minutes; the clinician should always be prepared
for this scenario. Increased intracranial pressure, concomitant ocular
trauma, and patients whose oral intake status is not known are patients
for which a subparalytic defasciculating dose of a nondepolarizing agent is
recommended.
Intubation
Pressure on the cricoid cartilage (Selek’s maneuver) should be applied as
spontaneous respirations begin to cease. Release should not occur until the
patient is intubated and the cuff is inflated [62,71]. The Selek maneuver
should be discontinued immediately if the patient vomits. Approximately 45
to 60 seconds after administration of succinylcholine, the patient should be
Table 3
Paralytic agents
Drug Time to intubation Clinical duration
Succinylcholine 40–60 s 6–12 min
Subparalytic dose + SCh 90–120 s 6–12 min
Rocuronium 45–75 s 30–60 min
Vecuronium 2–3 min 30–90 min
Rapacuronium 45–75 s 15–25 min
22 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
totally apneic and the jaw should be completely relaxed. If these conditions
are not met, the physician should wait an additional 15 seconds and reassess
for optimal conditions. It is better to wait for optimal paralysis than to rush
into a difficult intubation [75].
Once the patient has met optimal conditions, the clinician should
intubate the patient under direct visualization of the glottis. The tube should
be passed between the vocal cords, the stylet should be removed, the cuff
should be inflated, and placement should be confirmed with auscultation as
well as capnometry. Cricoid pressure should be released. Once there has
been confirmation of proper placement of the endotracheal tube, post-
intubation care should be undertaken (eg, sedation and paralysis, or, if
needed, ventilatory management and appropriate diagnostic tests).
Summary
Airway control is one of the most critical interventions required for
saving a life. It is essential that practitioners be as well trained as possible in
the numerous techniques available to establish airway control. This article
reviews some of the available techniques, though other techniques that are
not discussed (such as fiberoptic-assisted endotracheal intubation) may also
be useful. Perhaps the most important aspect of advanced airway manage-
ment is the ability to anticipate and prepare for the difficult airway. This
article gives numerous options for the difficult airway situation.
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26 M. Blanda, U.E. Gallo /Emerg Med Clin N Am 21 (2003) 1–26
	Emergency airway management
	Difficult intubations
	History
	Physical exam
	Alternative noninvasive techniques
	Digital/tactile intubation
	Directional tubes
	Stylets
	Lighted stylets
	Esophageal–tracheal tubes
	Laryngeal mask airway
	Nasotracheal intubation
	Invasive airway management
	Translaryngeal guided (‘‘retrograde’’) intubation
	Percutaneous transtracheal ventilation or needle cricothyrotomy
	Surgical cricothyrotomy
	Rapid sequence intubation
	Approach to RSI
	Preparation
	Preoxygenation
	Premedication
	Paralysis
	Intubation
	Summary
	References