Diagnosis and management of central airway obstruction Authors
Armin Ernst, MD, FCCP Felix JF Herth, MD, PhD Heinrich D Becker,
MD, FCCP Section Editor Praveen N Mathur, MB, BS Deputy Editor
Kevin C Wilson, MD Disclosures All topics are updated as new
evidence becomes available and our peer review process is complete.
Literature review current through: feb 2012. | This topic last
updated: mar 30, 2010. INTRODUCTION Central airway obstruction can
occur secondary to a number of malignant and benign processes
(table 1) [1]. Patients may develop symptoms suddenly (eg,
obstructing foreign body) or more gradually (eg, most malignant
obstructions). In many cases, patients are incorrectly diagnosed as
having asthma or chronic obstructive pulmonary disease, which
contributes to delayed recognition and therapy. Interventional
options for central airway obstruction are subject to the
availability of experienced personnel and equipment. In addition,
the stability of the patient, the nature of the underlying problem,
and the patient's overall prognosis and quality of life impact the
choice of intervention [1-5]. The broadest range of management
options are available at centers where a multidisciplinary team
specializes in the evaluation and management of the impaired
airway. The diagnosis and general approach to central airway
obstruction will be reviewed here. Specific management modalities
are discussed in detail separately. DIAGNOSIS The hallmark of the
severely compromised airway is impairment of oxygenation and
ventilation. Patients with minor obstruction are often
asymptomatic, since airflow limitation is mild. However, rapid
deterioration may occur if swelling or secretions increase the
degree of luminal impingement during a respiratory tract infection.
It is not uncommon for patients with subcritical lesions to be
misdiagnosed as suffering from an exacerbation of asthma or chronic
obstructive pulmonary disease (COPD) while the true etiology is
anatomic airway obstruction. Patients with airway obstruction also
frequently present with pneumonia; if symptoms and/or radiographic
infiltrates do not resolve within four to six weeks, bronchoscopy
should be considered. (See "Nonresolving pneumonia".) Symptoms and
signs develop when airflow impairment reaches a critical threshold.
Patients complain of shortness of breath, which is often constant
and unresponsive to bronchodilators. Monophonic wheezing may be
present, and can be unilateral if the lesion is distal to the
carina. Stridor is a sign of severe subglottic or tracheal
obstruction. Breathing becomes labored in advanced phases and
heralds impending respiratory failure.
The onset and progression of symptoms depend upon the nature of
the problem (acute with foreign bodies, slowly progressive with an
expansile goiter) and the location of the lesion (tracheal versus
bronchial). Patients with long-term artificial airways are at
increased risk for subglottic or tracheal stenosis and
tracheomalacia. Removal of the airway or capping of a tracheostomy
tube can result in shortness of breath or stridor, which should
prompt a thorough airway evaluation. (See "Endotracheal tube
management and complications" and "Overview of tracheostomy".) A
number of studies are employed to confirm the presence of central
airway obstruction and estimate its magnitude:
Plain chest radiographs are rarely diagnostic. Chest computed
tomography (CT) may detect airway compromise, but the test as
generally performed is not sensitive. If an airway lesion is
suspected and time permits, a high resolution CT with
three-dimensional airway reconstruction can prove helpful [6].
These new imaging protocols may assist in both the initial
assessment of the lesion and in objective grading of therapeutic
success and followup (figure 1). (See "Radiology of the trachea".)
Flow volume loops can show the characteristic changes of airway
obstruction, frequently before abnormalities in the spirometric
volumes are noted (figure 2A-E). (See "Flow-volume loops".) Direct
bronchoscopic visualization is the gold standard for confirming the
presence of airway obstruction and also aids in discerning its
underlying etiology. Often the differentiation of endobronchial or
extrinsic lesions can be accomplished only at bronchoscopy (figure
3). (See "Flexible bronchoscopy: Indications and
contraindications".)
MANAGEMENT Management of central airway obstruction is divided
into two phases: initial stabilization and airway interventions.
Initial stabilization In a stable patient, imaging studies and
pulmonary function tests should be obtained as outlined above. A
patient with severe tracheal or mainstem obstruction and marginal
lung function requires initial stabilization to secure ventilation
and oxygenation.
Endotracheal intubation is preferred. In the presence of a
compromised trachea, this is most safely performed with an awake or
mildly sedated patient who is still actively breathing. The use of
paralytic agents may be hazardous, since intubation may be
difficult or impossible. (See "Endotracheal tube management and
complications".) In cases of severe tracheal obstruction, use of
the open ventilating rigid bronchoscope is the preferred method of
airway control. (See "Rigid bronchoscopy: Intubation techniques".)
The rigid bronchoscope not only provides a secure airway during
visualization, but is also a therapeutic tool [7]. In emergent
cases, the airway can be dilated with the barrel of the scope
(figure 4A-B).
Bronchoscopy should be performed after the airway has been
secured and appropriate gas exchange documented. During the
bronchoscopic examination, the airway is inspected, lesions are
assessed, distal secretions are suctioned, and diagnostic tissue is
obtained if needed. This information is used to plan further
interventions aimed at opening an airway and maintaining patency.
If no dedicated airway team is available, patient transfer to a
specialized center should be considered after the patient has been
stabilized. An appropriate course of antibiotics should be
administered after a patent airway has been reestablished in
individuals with postobstructive infections. The usefulness of
empiric antibiotic therapy after interventions in the absence of
evidence of infection is unproven. Similarly, there is no evidence
that corticosteroids are effective in reducing complications in
this setting. It is advisable for all patients with a history of
airway obstruction to carry a card or bracelet identifying them as
patients with complicated airways or indwelling airway stents.
Airway interventions Further interventions are planned following
the initial assessment [1]. The number and scope of therapeutic
options has increased dramatically, and a given intervention must
be chosen carefully in the context of an individual patient's
situation [8]. Multimodality approaches featuring a combination of
several interventions are preferred for their mucosal sparing
effects and long term success over dilation alone (figure 5 and
table 2) [1,3]. The rigid bronchoscope is the preferred instrument
for unstable patients and when significant bleeding is expected.
Its nonflammable nature also makes it the preferred tool for many
laser bronchoscopies. For most other interventions, the flexible
bronchoscope with use of conscious sedation provides a therapeutic
alternative. (See "Rigid bronchoscopy: Instrumentation" and
"Flexible bronchoscopy: Equipment, procedure, and complications".)
Foreign body extraction Foreign body aspiration is more common in
children than adults, and can lead to sudden, catastrophic, central
airway obstruction. Both flexible and rigid bronchoscopy can be
used for foreign body extraction; the selection of procedure and
technique of removal are discussed elsewhere. (See "Airway foreign
bodies in adults".) Rigid or balloon dilation In emergent cases,
the airway may be dilated with the rigid bronchoscope. During this
procedure (called bronchoplasty), the patient is intubated with the
instrument under general anesthesia. The optical telescope is
advanced through the stenotic airway opening and the barrel then
pushed through the obstruction in a rotating motion. Bleeding is
usually minimal due to compression of the lesion by the rigid
instrument (figure 4A-B). In less urgent cases, sequential balloon
or rigid dilators may be used, particularly when the stenosis
occurs after transplantation or long term intubation. For
sequential rigid dilation, the patient must be preoxygenated
carefully, which may not be feasible in severe airway stenosis.
Balloon dilation can safely be performed with the flexible
bronchoscope (figure 6) [9]. The major advantage of sequential
rigid versus balloon dilation is that there generally is less
mucosal trauma. (See "Flexible fiberoptic bronchoscopy balloon
dilation".)
Dilation is immediately effective for intrinsic and extrinsic
lesions, but the results are usually not sustained. Mucosal
disruption from these techniques may in fact produce granulation
tissue and accelerate recurrent stenosis [10]. For this reason,
dilation is frequently followed by laser and/or stenting
procedures, as described below [11]. Laser therapy Nd:YAG laser
therapy is frequently performed utilizing the rigid bronchoscope,
but can be safely performed with the flexible bronchoscope by
experienced endoscopists [12]. The tissue-light interaction leads
to thermal tissue damage and destruction of obstructing lesions
[13]. (See "Basic principles of medical lasers" and "Bronchoscopic
laser resection".) Laser therapy is indicated for short
endobronchial central airway lesions with a visible distal lumen.
The technique is most commonly applied in cases of malignant
intrinsic airway obstruction or in postintubation tracheal
stenosis. The effects upon airway lumen size are usually immediate
and accompanied by excellent control of bleeding, but as is true
with dilation, they are not long-lasting. Large series have
demonstrated the safety of laser therapy in experienced hands [14].
Complications include combustion of the endotracheal tube or
fiberoptic bronchoscope, hypoxemia, respiratory failure, and
destruction of bronchial wall components. Electrocautery and argon
plasma coagulation These therapies also rely on thermal tissue
destruction. With electrocautery, a high-frequency current is
applied to the lesion with bipolar probes. When the current is
directly applied to the tissue, heat develops and leads to tissue
necrosis. (See "Endobronchial electrocautery".) Argon plasma
coagulation is a related therapeutic intervention [15]. Argon gas
is emitted through a Teflon tube that can be passed through a
flexible bronchoscope. This gas is ionized because of exposure to
high-frequency current and an electrical arc is formed which allows
for desiccation and tissue destruction without direct contact. The
penetration depth is reliably 2 to 3 mm, which makes the argon
plasma coagulator a valuable tool in treating superficial bleeding
and debulking granulation tissue and tumors such as papillomas
(figure 7) [1]. Photodynamic therapy Photodynamic therapy is
approved for malignant intrinsic airway obstruction due to lung
cancer that is unresponsive or unsuitable for laser therapy. After
injection of a photosensitizing agent and a suitable time interval,
tumor tissue that has retained the photosensitizing agent is
exposed to a laser light of 630 nm wavelength. The laser is
delivered through a fiber introduced through the flexible
bronchoscope. A nonthermal phototoxic reaction leads to delayed
cell death [1,16,17]. (See "Photodynamic therapy of lung cancer".)
This therapeutic approach is also suitable for completely
obstructed airways due to the predictable penetration depth of 5 to
10 mm. Follow-up bronchoscopy is necessary to remove debris and
secretions. The main adverse effect of this approach is associated
skin photosensitivity, which can last up to six weeks.
Cryotherapy As opposed to the thermal effects of laser therapy,
cryotherapy relies on repeated freeze/thaw cycles for tissue
destruction. Cryotherapy may be performed through the flexible
bronchoscope and spares cartilaginous structures due to their poor
vascularity. The intervention is more time-consuming than laser
therapy because of the need for repeat cycles, and a repeat
bronchoscopy for clearance of debris and secretions is usually
necessary [18,19]. (See "Bronchoscopic cryosurgery: Principles and
technique" and "Bronchoscopic cryosurgery: Indications,
contraindications, and outcomes".) Cryotherapy can be performed
safely in complete mainstem obstruction, but its delayed effects do
not make it a first choice in acute situations or severe tracheal
stenosis. As with any tissue-destroying interventions, long-term
stabilization of the airway is often necessary. Stenting or
radiation in the case of malignant lesions may achieve this.
External beam radiation and brachytherapy Radiation therapy is a
variably effective treatment for malignant airway obstruction, and
therapeutic effects may be quite delayed. External beam radiation
also may produce unwanted effects on thoracic structures outside
the airway, further compromising gas exchange. Endobronchial
brachytherapy is a treatment modality that has fewer of these
drawbacks and is particularly useful in patients who have received
previous maximal doses of external beam radiation [20]. (See
"Endobronchial brachytherapy".) After a patent airway has been
established by laser resection, dilation, or other methods, a
hollow catheter is introduced through the flexible bronchoscope and
positioned under direct vision. After the catheter is secured, it
is loaded with a radioactive source [21,22]. Depending upon the
results, airway stenting should be considered. Adverse effects of
brachytherapy are usually minimal (tracheobronchitis, cough), but
severe hemoptysis and fistula formation have been reported [22].
Airway stents Stenting should be considered to prevent reocclusion
after patency has been restored to occluded or severely stenotic
airways. Stents are the intervention of choice for external
obstruction and are also highly effective for persistent proximal
bronchopleural fistulas and tracheoesophageal fistulas [23,24]. The
first dedicated tracheobronchial stent was introduced in 1990;
numerous designs with various advantages and disadvantages are now
available [25-27]. (See "Airway stents".) Silicone stents generally
require introduction with a rigid bronchoscope, but are
comparatively inexpensive. Most metal stents can be introduced with
the flexible bronchoscope; their greater expense is partially
offset by the fact that neither an operating room nor general
anesthesia is needed [28,29]. New stent designs combining different
materials are currently being evaluated [30-32]. Stents are
generally well tolerated, but patients require periodic follow-up.
Patients should carry a card detailing type and size of the
indwelling stent. Stents do not contraindicate subsequent
intubation, but intubation should preferably be performed under
fiberoptic guidance if the stent is in the tracheal position.
Meticulous follow-up is indicated to identify potential problems
at an early stage. These include recurrence of obstruction, growth
of granulation tissue, as well as stent occlusion and migration. If
identified early, these complications can be addressed in an
elective manner. At our institution, a first follow-up bronchoscopy
after stent placement is performed after six to eight weeks, which
allows for repositioning of migrated metallic stents. Thereafter,
we perform interval bronchoscopies every three to six months and as
problems arise. Surgical resection Surgical intervention for airway
obstruction is usually reserved for severe, benign, relatively
short tracheal lesions. Patient selection is crucial, as the
operative morbidity and mortality may be unacceptable in patients
with limited cardiopulmonary reserve. Patients should be referred
to a center with a large cumulative experience if surgical
resection is a consideration. Techniques that are commonly employed
are primary end-toend anastomosis and tracheal sleeve resection
[33-35]. Anastomotic complications that result in recurrent
stenosis may necessitate multiple dilations, reoperation, or
permanent tracheostomy. These complications were noted in 9 percent
of patients in one large single center series of over 900
procedures [36]. Risk factors for complications following tracheal
resection in this study included diabetes, prior tracheal
resection, and stenotic lesions longer than 4 cm [36]. Patients
undergoing laryngotracheal resection were also at increased risk of
anastomotic complications in this report. In the future, biological
tissue engineering techniques may be used to create tracheal
bioprostheses covered with mucosal tissue [37-44]. Tracheal
transplantation, which has been difficult to achieve because of the
limited blood supply to the airway, may also be possible as muscle
flap reconstruction techniques continue to improve [45,46].
RECOMMENDATIONS Central airway obstruction may be extrinsic or
intrinsic and may cause a variety of symptoms, from shortness of
breath to respiratory failure and death. In the decompensated
patient, immediate restoration of ventilation and oxygenation is of
vital importance. Subsequent interventions are based upon the
nature of the obstruction and refined according to issues involving
quality of life and the duration of expected survival. Frequently,
the best therapeutic approach employs a combination of several
treatment modalities, and should be chosen at any given time in
such a way that leaves open options for further therapy (figure 5).
Close follow-up is necessary in order to recognize complications
early and intervene accordingly. The most comprehensive assessment
and therapy can be provided by centers with a multidisciplinary
airway team specializing in compromised airways. Use of UpToDate is
subject to the Subscription and License Agreement.
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TOPIC OUTLINE
INTRODUCTION DIAGNOSIS MANAGEMENT Initial stabilization Airway
interventions - Foreign body extraction - Rigid or balloon dilation
- Laser therapy - Electrocautery and argon plasma coagulation -
Photodynamic therapy - Cryotherapy - External beam radiation and
brachytherapy - Airway stents - Surgical resection RECOMMENDATIONS
REFERENCES
GRAPHICSView All
FIGURES CT reconstruction of trachea Upper airway obstruction
Flow volume loops airway obstr Mainstem bronchial obstr Partial
mainstem bronchial obs End inspiratory tail Central obstruction
types Rigid bronchoscope Dilation with rigid scope Management
central obstruction Balloon dilation Juvenile papillomatosis bronch
TABLES Causes central airway obstruct Interventions cent
obstruction
RELATED TOPICS
Airway foreign bodies in adults Airway stents Basic principles
of medical lasers Bronchoscopic cryosurgery: Indications,
contraindications, and outcomes Bronchoscopic cryosurgery:
Principles and technique Bronchoscopic laser resection
Endobronchial brachytherapy Endobronchial electrocautery
Endotracheal tube management and complications Flexible
bronchoscopy: Equipment, procedure, and complications Flexible
bronchoscopy: Indications and contraindications Flexible fiberoptic
bronchoscopy balloon dilation Flow-volume loops Nonresolving
pneumonia Overview of tracheostomy Photodynamic therapy of lung
cancer Radiology of the trachea Rigid bronchoscopy: Instrumentation
Rigid bronchoscopy: Intubation techniques
Help improve UpToDate. Did UpToDate answer yo The failed airway
in adults Authors Ron M Walls, MD, FRCPC, FAAEM Michael F Murphy,
MD, FRCPC
Section Editor John A Marx, MD Deputy Editor Jonathan Grayzel,
MD, FAAEM Disclosures All topics are updated as new evidence
becomes available and our peer review process is complete.
Literature review current through: feb 2012. | This topic last
updated: jun 14, 2010. INTRODUCTION A failed airway exists at any
time during an attempt at endotracheal intubation when there is an
inability to intubate the patient (even with a single attempt) and
an inability to ventilate the patient adequately with a bag and
mask to maintain oxyhemoglobin saturations above 90 percent. This
is the "can't intubate, can't ventilate" type of failed airway. A
second form of failed airway has been defined for emergency
intubation, and exists when there have been three failed attempts
to intubate by an experienced operator, even when bag and mask
ventilation is capable of maintaining adequate oxyhemoglobin
saturation [1]. This is the "can't intubate, can ventilate" type of
failed airway. When either of these two situations arises during
emergency airway management, the clinician must take effective
action immediately to avoid oxygen desaturation with resultant
cerebral hypoxia. A failed airway can arise during a rapid sequence
intubation, during management of a difficult airway, or during
management of a crash airway. Regardless of the circumstances
leading to the airway failure, a deliberate approach must be used
to ensure that oxygenation is preserved, and that the airway is
ultimately secured. This topic review will discuss management of
the failed airway. Discussions of other aspects of airway
management are found elsewhere. (See "Rapid sequence intubation in
adults" and "The difficult airway in adults" and "The difficult
pediatric airway" and "Emergent endotracheal intubation in
children".) INCIDENCE OF THE FAILED AIRWAY The incidence of the
failed airway, as defined above, is not known for emergency
department (ED) airway management, nor for patients undergoing
anesthesia in the operating room. Analysis of nearly 9000 ED
intubations in the National Emergency Airway Registry (NEAR) found
that rapid sequence intubation is successful in approximately 97
percent of cases for which it is the first method chosen, and that
surgical cricothyroidotomy (also called cricothyrotomy) is required
in approximately 0.8 percent of all emergency intubations and 1.7
percent of intubations of trauma patients [2,3]. An earlier, single
center study of 610 emergency intubations noted a cricothyroidotomy
rate of 1.1 percent [4]. (See "Emergent surgical cricothyrotomy
(cricothyroidotomy)".) It is likely that the incidence of failed
airway, particularly of the can't intubate, can ventilate type, is
much higher than this. Regardless of the incidence, the failed
airway represents a potential catastrophe if not managed
effectively. The failed airway scenario is best avoided
by a systematic preintubation evaluation of patients for
difficult airway attributes. (See "The difficult airway in
adults".) THE FAILED AIRWAY ALGORITHM When a failed airway occurs,
the failed airway algorithm provides a series of actions to guide
management (algorithm 1) [1,5]. The critical question is whether
adequate oxygenation (ie, oxyhemoglobin saturation [SpO2] above 90
percent or stable in the high 80s) can be maintained. If
oxygenation is adequate, there is time to plan a series of actions
to manage the airway; if the patient's oxygenation cannot be
maintained, immediate rescue by (usually) cricothyrotomy is
necessary. If time permits, there are a number of alternative or
rescue devices that can be used when direct laryngoscopy has
failed. In some cases, the rescue airway may provide a definitive
airway, with a cuffed endotracheal tube (ETT) in the trachea. If
the airway is secured by a cuffed ETT, the airway is considered to
be managed, and general resuscitation continues. If adequate
oxygenation and ventilation are achieved, but the airway is not
protected by a cuffed ETT in the trachea, resuscitation can
continue, but arrangements must be made to establish a definitive
airway at the earliest appropriate opportunity. As with the
difficult airway algorithm, the response to the failed airway can
be thought of as a series of discrete steps. Each of these steps is
described in detail below. Assistance in the form of personnel,
equipment, or airway devices, should be obtained as needed at the
moment the failed airway is recognized. Is there time? At the
outset, the key determination is whether the patient is being
adequately oxygenated (ie, oxyhemoglobin saturation [SpO2] above 90
percent or stable in the high 80s). If so, there is time to create
and execute a deliberate rescue plan, perhaps customized to the
patient's particular circumstances. This is the "can't intubate,
can ventilate" scenario. If the patient cannot be oxygenated
adequately with a bag and mask, despite use of optimal technique
(ie, can't intubate, can't oxygenate), immediate cricothyrotomy is
indicated. Although an alternative airway device might rescue the
patient without cricothyrotomy, the extremely brief time before
cerebral hypoxia ensues argues for immediate surgical intervention.
Attempts to establish an alternative airway, if unsuccessful, may
delay the initiation of cricothyrotomy leading to hypoxic brain
injury. Thus, we equate "can't intubate, can't ventilate" with
cricothyrotomy in the emergency setting. There is one modification
to this approach. Placement of a single "best" alternative device,
usually an extraglottic airway (eg, Laryngeal Mask Airway (LMA) or
King LT Airway) can be attempted in parallel with preparations for
the surgical airway. If the operator is able to insert an
extraglottic airway and attempt ventilation, while a second
clinician simultaneously prepares for a cricothyrotomy, then
valuable time is not lost if ventilation using the extraglottic
device is unsuccessful. Similarly, a single operator might make one
attempt with an extraglottic device, then proceed directly to
cricothyrotomy if ventilation is not promptly achieved. This
approach
involves a single attempt using a single "go to" device, and
cannot delay significantly the initiation of cricothyrotomy if
ventilation is not achieved immediately. Whether this single,
parallel rescue maneuver is attempted but unsuccessful or not
attempted, the primary rescue technique is cricothyrotomy. The
performance of cricothyrotomy is discussed separately. (See
"Emergent surgical cricothyrotomy (cricothyroidotomy)".)
ALTERNATIVE AIRWAY DEVICES The initial goal for failed airway
management is to provide adequate oxygenation sufficient to support
the patient until a definitive airway can be achieved. So long as
the patient is adequately oxygenated using a bag and mask, the
clinician may use any of several alternatives to direct
laryngoscopy to rescue the failed airway. The devices briefly
described below are discussed in detail separately. (See "Devices
for difficult emergency airway management in adults".) List of
devices
Fiberoptic or video stylet - There are several rigid or
semi-rigid fiberoptic and video stylets available (eg, Shikani
Optical Stylet [SOS] or Storz Bonfils laryngoscope). These stylets
have fiberoptic or video viewers at their distal end and are
inserted through the endotracheal tube (ETT). The image generated
can be used to guide the ETT between the vocal cords without need
of a conventional laryngoscope. Video laryngoscopes - Video
laryngoscopes (eg, Glidescope or Storz C-MAC) contain video cameras
on the blade that generally provide an excellent view of the
glottis, without the need to align the airway axes to achieve a
direct view from outside the patient's mouth. These devices
function well with the patient in the neutral position, and
obstacles to conventional laryngoscopy, such as limited mouth
opening or a large tongue, generally do not present a problem.
Optical devices Various optical devices are available for
intubation of the failed airway or as an alternative to direct
laryngoscopy. The best studied of these is the AirTraq, a
periscope-like device that uses prisms and mirrors to provide an
indirect view of the glottis. The AirTraq incorporates a channel
for the ETT, which is advanced when the glottis is properly
sighted. Extraglottic airway - Various laryngeal mask airways
(LMAs) are available, some specifically designed to facilitate
subsequent intubation, some intended strictly as ventilatory
devices in their own right. A second type of extraglottic airway is
inserted into the esophageal inlet and has two balloons that are
inflated to occlude both the esophagus and the pharynx thereby
permitting sidestream ventilation of the trachea. Available devices
include the Combitube and the King LT airways. Flexible
bronchoscope - The flexible bronchoscope, usually an intubating
bronchoscope, provides access to the glottis without having to
correct for the various angles of the oropharynx, as is required
for direct laryngoscopy. Intubation can be achieved nasally or
orally, but by either route, attempts can be timeconsuming, making
this device more appropriate for a planned approach to certain
difficult airways, rather than for the rescue of a failed airway.
Attempts using the fiberoptic bronchoscope may have to be
abbreviated or abandoned because of the difficulty maintaining
oxygenation during fiberoptic airway procedures. Flexible
bronchoscopes require training and practice, but have high
success rates when time permits [6]. Was a cuffed endotracheal tube
placed in the trachea? Many of the alternative airway devices
listed above result in a cuffed ETT in the trachea, in which case,
the airway is secured. Others, such as the extraglottic airways,
provide for ventilation and oxygenation, but do not protect the
airway. If one of the nonprotective devices has been used,
resuscitation can proceed, but a plan must be initiated to secure
the airway at the earliest opportunity. If at any time oxygenation
fails, and the patient reverts to a can't intubate, can't ventilate
situation, cricothyrotomy remains the rescue technique of first
resort. SUMMARY AND RECOMMENDATIONS
A failed airway exists at any time during an attempt at
endotracheal intubation when there is an inability to intubate the
patient (even with a single attempt) and an inability to ventilate
the patient adequately using a bag and mask or an extraglottic
device (ie, maintain oxyhemoglobin saturations [SpO2] above 90
percent or stable in the high 80s). This is the "can't intubate,
can't ventilate" type of failed airway. A failed airway also exists
when there have been three failed attempts to intubate by an
experienced operator, even when ventilation with a bag and mask or
an extraglottic device maintains adequate SpO2. This is the "can't
intubate, can ventilate" type of failed airway. (See 'Introduction'
above.) We recommend that cricothyrotomy be used as the primary
rescue maneuver for the "can't intubate, can't ventilate" failed
airway (Grade 1C). Cricothyrotomy has a high success rate and
relatively low complication rate, and can be performed using open
surgical technique or a Seldinger method. (See 'The failed airway
algorithm' above.) The critical question in failed airway
management is whether adequate oxygenation (ie, SpO2 above 90
percent or stable in the high 80s) can be maintained. If
oxygenation is adequate there is time to plan a series of actions
to manage the airway; if the patient's oxygenation cannot be
maintained, immediate rescue by (usually) cricothyrotomy is
necessary. (See 'The failed airway algorithm' above and "Emergent
surgical cricothyrotomy (cricothyroidotomy)".) For the can't
intubate, can ventilate patient, there are several possible rescue
devices. (See 'Alternative airway devices' above.) For ventilation
only: Extraglottic airway (eg, Combitube, King LT, Laryngeal mask
airway)
For intubation:
Intubating LMA Rigid fiberoptic or video stylet Video
laryngoscope Optical device (eg, AirTraq) Flexible fiberoptic
scope
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REFERENCES1. Walls, RM. The Emergency Airway algorithms. In:
Manual of Emergency Airway Management, Walls, RM, Murphy, MF,
Luten, RF, et al (Eds). Philadelphia, Lippincott, Williams and
Wilkins 2004. p 8. 2. Sagarin MJ, Barton ED, Chng YM, et al. Airway
management by US and Canadian emergency medicine residents: a
multicenter analysis of more than 6,000 endotracheal intubation
attempts. Ann Emerg Med 2005; 46:328. 3. Walls, RM, et al.
Emergency Airway Management: A Multi-center Report of 8937
Emergency Department Intubations. J Emerg Med 2010; [Epub ahead of
print]. 4. Sakles JC, Laurin EG, Rantapaa AA, Panacek EA. Airway
management in the emergency department: a one-year study of 610
tracheal intubations. Ann Emerg Med 1998; 31:325. 5. The airway
management algorithms cited in this review are reproduced with
permission from: The Difficult Airway Course: Emergency, and Walls,
RM, Murphy, MF. Manual of Emergency Airway Management, 3rd ed,
Lippincott Williams & Wilkins, Philadelphia 2008. 6. Dunn S,
Connelly NR, Robbins L. Resident training in advanced airway
management. J Clin Anesth 2004; 16:472. Topic 274 Version 3.0 The
difficult pediatric airway Author Nathan W Mick, MD Section Editor
Susan B Torrey, MD Deputy Editor James F Wiley, II, MD, MPH
Disclosures All topics are updated as new evidence becomes
available and our peer review process is complete. Literature
review current through: feb 2012. | This topic last updated: oct
12, 2011. INTRODUCTION Effective airway management includes
anticipating and planning for problems. Difficulties frequently
occur as the result of patient characteristics that interfere with
spontaneous breathing, bag mask ventilation, laryngoscopy, and/or
intubation of the trachea. Identifying characteristics of the
difficult airway and developing a plan for managing problems are
essential principles of anesthesia practice [1]. These principles
have been modified and effectively used to evaluate adults in the
emergency department [2]. Children infrequently require aggressive
airway management and difficulties do not occur often [3]. As a
result, evidence specific for children regarding identification and
management of difficult airways is limited [4]. Nevertheless, a
reasonable, systematic approach for children can be developed from
experience with adult patients in the operating room and emergency
department.
This topic will review conditions in children that can make
airway management difficult, anatomic characteristics that may
identify those conditions, and management strategies. General
principles of airway management in children, including rapid
sequence intubation, and the adult with a difficult airway are
discussed separately. (See "Basic airway management in children"
and "Emergent endotracheal intubation in children" and "Rapid
sequence intubation in children" and "The difficult airway in
adults".) DEFINITION A difficult airway is generally defined as a
situation in which a clinician experiences difficulty with face
mask ventilation, laryngoscopy, or intubation [1,2]. In an
emergency setting, this also includes difficulty performing an
emergency surgical airway, such as needle cricothyroidotomy. These
difficulties may arise whenever any of the following maneuvers
cannot be successfully performed:
Positioning to optimally align the pharyngeal and tracheal axes
(picture 1). Achieving sufficient positive pressure with a
resuscitation bag to inflate the lungs. Opening the mouth and
controlling oral structures with the laryngoscope blade.
Visualizing the larynx and intubating the trachea. Identifying
landmarks in the neck for performing a surgical airway.
CAUSES OF THE DIFFICULT PEDIATRIC AIRWAY Normal pediatric airway
Predictable differences in the pediatric airway (as compared with
adult airway anatomy) may make management difficult. These
differences, most evident in children less than two to three years
of age, include the following (see "Emergency airway management in
children: Unique pediatric considerations"):
A large occiput affects positioning. A large tongue and small
mouth may make laryngoscopy difficult. The larynx may be harder to
locate with the laryngoscope because it is higher and more anterior
than in an adult. The epiglottis is large and floppy and may
difficult to control.
Anatomic features of the normal pediatric airway are reviewed
elsewhere. (See "Basic airway management in children", section on
'Anatomic considerations' and "Emergent endotracheal intubation in
children".) Congenital abnormalities Numerous congenital conditions
have features that may make airway management difficult (table 1).
In addition, children with underlying airway abnormalities who
acquire an acute condition (such as croup or an upper respiratory
tract infection) may quickly develop respiratory compromise.
Congenital features that may interfere with airway management
include the following:
Misshapen head Positioning of the head to optimally align the
pharyngeal and tracheal axes may be difficult if the head is
misshapen, as can occur with
craniosynostosis (such as Apert's or Crouzon's syndrome) or
hydrocephalus. (See "Craniosynostosis syndromes" and
"Hydrocephalus".) Facial abnormalities Facial asymmetry or
underdevelopment may make it difficult to achieve a good seal
between the face and a mask, creating difficulties with bag mask
ventilation (picture 2). As examples, maxillary hypoplasia is a
feature of Apert's syndrome, while Goldenhar syndrome includes
unilateral hypoplasia of the mandible. (See "Syndromes with
craniofacial abnormalities".) Abnormal neck mobility Limited neck
mobility (as occurs with Klippel- Feil syndrome) or cervical spine
instability (which can occur with Down syndrome and the
mucopolysaccharidoses) may interfere with positioning of the head.
(See "Clinical features and diagnosis of Down syndrome", section on
'Atlantoaxial instability' and "Complications and management of the
mucopolysaccharidoses", section on 'Anesthesia'.) Small oral
aperture Opening the mouth for laryngoscopy may be difficult in
children with microstomia, which is a feature of Freeman-Sheldon
and HallermannStrieff syndromes. Small oral cavity Children with
small mandibles or palatal abnormalities (such as high arched or
cleft palates) have a smaller oral cavity. This may make
laryngoscopy and control of oral structures difficult. For
instance, mandibular hypoplasia is a feature of the Robin sequence
and Treacher Collins' syndrome (picture 3). Large tongue A large
tongue may obstruct the airway during bag mask ventilation or be
difficult to control during laryngoscopy. Macroglossia occurs in
several conditions (such as hypothyroidism, Beckwith-Wiedeman
syndrome, and Down syndrome). It is also a feature of infiltrative
diseases such as the mucopolysaccharidoses. Masses Masses in the
neck (such as cystic hygromas) may interfere with positioning.
Masses within the airway (such as teratomas or hemangiomas) may
obstruct the airway and interfere with visualization of the larynx.
Mediastinal masses may make tube placement difficult and interfere
with ventilation after successful intubation [5]. (See "Congenital
anomalies of the jaw, mouth, oral cavity, and pharynx" and
"Epidemiology; pathogenesis; clinical features; and complications
of infantile hemangiomas", section on 'Airway hemangiomas'.)
Laryngeal and subglottic abnormalities Abnormalities of the larynx
or subglottic trachea may interfere with intubation (picture
4).
Acquired conditions Acquired conditions that can cause
difficulties with airway management may develop as the result of
infection, allergic reactions, trauma, or aspiration of a foreign
body. Infection The specific difficulties in airway management that
arise because of Infection depend upon where the infection is
located within the airway.
Retropharyngeal and peritonsillar abscesses may interfere with
laryngoscopy and visualization of the larynx. These conditions do
not typically require emergency airway management. (See
"Retropharyngeal infections in children".)
Epiglottitis is characterized by rapidly progressive
inflammation and edema of the supraglottic structures. Airway
management is difficult because laryngeal anatomy is distorted and
the glottic opening may be small and difficult to identify. Since
the introduction of conjugate Haemophilus influenza type B
vaccines, the incidence of epiglottitis in children has declined
dramatically. (See "Epiglottitis (supraglottitis): Clinical
features and diagnosis".) Croup and tracheitis cause subglottic
airway obstruction. As a result, it may be difficult to deliver
effective bag mask ventilation or to pass an endotracheal tube
through the subglottic trachea. Fortunately, both conditions
generally respond to medical management. (See "Clinical features,
evaluation, and diagnosis of croup", section on 'Pathogenesis' and
"Approach to the management of croup".)
Anaphylaxis Edema involving the tongue, retropharynx, and/or
larynx, that can interfere with laryngoscopy and visualization of
the larynx, may develop as the result of anaphylaxis. Symptoms
typically respond to aggressive medical management (table 2).
Trauma Injury to the face or airway (as the result of blunt or
penetrating trauma, thermal burns, or caustic ingestions) may
complicate airway management. Facial burns may make it difficult to
deliver bag mask ventilation because an adequate seal between the
mask and face cannot be achieved. An expanding hematoma in the
pharynx can interfere with laryngoscopy. Injury to the larynx or
subglottic trachea may be exacerbated by intubation. Spinal
immobilization with a rigid cervical collar, regardless of the
presence of injury can make direct laryngoscopy difficult because
the clinician is unable to optimally position the patient in the
sniffing position and adequately align the visual axis. (See
'Management' below.) Foreign body A foreign body in the airway may
cause significant obstruction and require immediate treatment.
Identification and removal of the foreign body during laryngoscopy
can be challenging. In addition, normal anatomic landmarks may be
distorted by the foreign body. (See "Emergent evaluation of acute
upper airway obstruction in children", section on 'Causes'.)
Piercings around the mouth and tongue may interfere with or become
dislodged during laryngoscopy [6]. Other causes Other acquired
conditions in children that may make airway management difficult
include tumors, previous surgery, or radiation treatment.
IDENTIFICATION OF THE DIFFICULT PEDIATRIC AIRWAY The initial
evaluation of any critically ill or injured child should include a
brief, systematic assessment of the airway to identify
characteristics that may complicate management. These
characteristics must be taken into consideration when developing an
airway management plan. (See "Emergent endotracheal intubation in
children" and "Rapid sequence intubation in children", section on
'Preparation'.) Anesthesiologists have used bedside evaluation
tools to identify patients for whom airway management may be
difficult [1]. None of these indicators has been tested in
emergency
departments or in children. Nevertheless, a reasonable approach
can be developed using evidence from the operating room and
clinical experience in the emergency department to identify
children who may have difficult airways [2]. Bag mask ventilation
Bag mask ventilation may be difficult in children with the
following features:
A misshapen head (as the result of trauma or a congenital
anomaly) or limited neck mobility (such as a patient whose cervical
spine is immobilized) can interfere with proper positioning
(picture 1). Facial burns or any disruption of lower facial
continuity (as can occur with facial trauma or a congenital anomaly
with facial asymmetry) can make it difficult to achieve an adequate
seal between the face and the mask. Patients who are obese or who
have significant lung disease (such as severe asthma) may be
difficult to ventilate with a bag and mask [7].
Laryngoscopy or intubation A combination of several clinical
features appears to be a sensitive predictor of difficult
laryngoscopy or intubation for adults [8-10]. These features
include:
Interincisor gap is the distance between the upper and lower
incisors with the mouth open as wide as possible. For adult
patients, the width of three of the patient's fingers is considered
an adequate distance for laryngoscopy [2]. Mallampati score
assesses the view of the posterior pharynx with the mouth wide open
(figure 1). Intubation may be difficult for patients with a poor
view (Class III or IV). However, when used alone, the score has
limited accuracy for predicting a difficult airway [11].
Thyromental distance is the distance between the tip of the chin
and the thyroid notch. Typically, the width of three of the
patient's fingers is considered normal for adults [2]. Difficulty
visualizing the larynx may occur when the distance is longer or
shorter.
Cricothyroidotomy Needle cricothyroidotomy, which permits
percutaneous transtracheal ventilation, should always be considered
a difficult technique in children because normal landmarks are
difficult to identify and the caliber of the airway is small. In
addition, few if any practitioners are able to gain proficiency
with these techniques because clinical scenarios that require them
occur rarely. (See 'Surgical airway' below.) The LEMON approach to
difficult airway assessment The mnemonic LEMON has been developed
by researchers in emergency airway management as a tool for rapidly
identifying adult patients who may have a difficult airway (table
3) [2,12]. The tool has not been tested in children. Components of
the mnemonic include the following:
L: Look externally for indicators of a difficult airway (such as
a misshapen head, facial abnormalities, or neck masses). E:
Evaluate mouth opening, thyromental distance, and the distance
between the mandible and the thyroid cartilage (this correlates
with the distance between the
base of the tongue and the larynx) (figure 2). Adequate mouth
opening and thyromental distance should be the width of three of
the patient's fingers. The distance between the mandible and
thyroid cartilage should be the width of two fingers. M: Mallampati
score: Assigning a Mallampati score may be difficult in young
children. For the obtunded, supine patient, a crude assessment can
be made using a tongue blade (figure 1) [2]. O: Obstruction: Signs
of airway obstruction (such as stridor, a muffled voice, or
difficulty handling secretions) always indicate that airway
management may be difficult. Upper airway obstruction can interfere
with bag mask ventilation, as well as with laryngoscopy and
intubation. N: Neck mobility: Conditions that limit neck mobility
(such as congenital anomalies or cervical spine immobilization) can
usually be identified by observation.
ALTERNATIVE AIRWAY TECHNIQUES Alternative strategies for
providing oxygenation and ventilation must be considered for the
child who may be difficult to intubate with direct laryngoscopy.
These techniques may be temporizing (such as laryngeal mask airway,
combitube, or a percutaneous needle cricothyrotomy) or provide
alternative approaches to tracheal intubation (as with fiberoptic
intubation or a lighted stylet). Several factors impact the choice
of device including the clinical situation, type of airway
difficulty, and experience of the operator. (See "Devices for
difficult endotracheal intubation in children", section on 'Choice
of device' and "Emergency rescue devices for difficult pediatric
airway management", section on 'Choice of device'.) Laryngeal mask
airway The laryngeal mask airway (LMA) consists of a cuffed mask,
designed to fit over the larynx, which is attached to a tube
similar to an endotracheal (ET) tube. The LMA is inserted into the
mouth and blindly passed along the palate into the posterior
pharynx until resistance is met. The cuff is then inflated and the
mask forms a partial seal around the larynx. Positive pressure
ventilation can then be delivered through the tube. The procedure
for placing the LMA in children is described in detail separately.
(See "Emergency rescue devices for difficult pediatric airway
management", section on 'Laryngeal mask airway (LMA)'.) The device
is available in multiple sizes suitable for infants, children, and
adults. The appropriate size is based on the patient's weight
(table 4). The LMA has been used extensively by anesthesiologists
in the operating room for children with normal and difficult
airways [13-16]. It is relatively easy to insert, although
complications with its use have been reported in infants and small
children [17]. It has been used as a primary airway and as an
adjunct for fiberoptic tracheal intubation [18,19]. (See 'Flexible
fiberoptic intubation' below.) The LMA may provide effective airway
management for adults during resuscitation [20]. In addition,
successful oxygenation and ventilation with an LMA have been
described in adults with upper airway obstruction from supraglottic
edema [21]. However, experience with the device as a rescue airway
in children is limited [22]. Case series and reports suggest that
an adequate airway can be achieved with an LMA in neonates when
bag-mask ventilation and tracheal intubation have failed [23].
An LMA with a modified cuff (Proseal LMA) appears to provide a
better seal over the larynx for children, allowing for more
effective delivery of positive pressure ventilation [24,25]. The
device also has an esophageal drainage tube through which a gastric
tube can be placed to empty the stomach. It is available in the
full range of pediatric sizes. Intubating introducers (gum elastic
bougie) Intubating introducers are helpful when the epiglottis is
visible but the vocal cords cannot be seen. These devices are
semi-rigid solid or hollow rods with the distal tip bent at a 30
degree angle (figure 3 and figure 4). Pediatric sized introducers
allow placement of endotracheal tubes as small as 4.0 mm (internal
diameter). Lighted stylet The pediatric lighted stylet is a rescue
device that does not require direct visualization of the vocal
cords [26]. A stylet with a fiberoptic light source is inserted
into an endotracheal tube that is then blindly placed into the
posterior pharynx and advanced. The tube is usually located in the
trachea when a cherry-red glow is noted at the suprasternal notch.
The stylet can then be carefully removed, endotracheal tube
placement confirmed, and the tube secured. This technique has been
used successfully for infants and children but has a relatively low
success rate (75-83%) when the technique is performed by
inexperienced users [27,28]. It can often be performed with minimal
movement of the patient's head and neck, making it particularly
useful for trauma patients whose cervical spines are immobilized
[29]. (See "Devices for difficult endotracheal intubation in
children", section on 'Lighted stylet'.) Fiberoptic stylets These
devices combine features of the lighted stylet with features of a
flexible fiberoptic bronchoscope to create a device that can be
used for blind intubation similar to a lighted stylet or visually
guided intubation. With this technique an endotracheal tube is
loaded onto a stylet with a fiberoptic lens that allows the
clinician to visualize the glottis. The endotracheal tube is then
threaded through the glottis and secured. (See "Devices for
difficult endotracheal intubation in children", section on
'Fiberoptic stylets'.) Flexible fiberoptic intubation Flexible
fiberoptic techniques have been used extensively by
anesthesiologists for difficult intubations [1,19]. Experience with
this approach in the emergency department is almost exclusively in
adult patients [30]. Typically, an endotracheal tube is threaded
onto the end of a flexible fiberoptic bronchoscope. The scope is
then introduced into the nose or mouth. The trachea is visualized
and intubated with the scope and endotracheal tube. The scope is
then withdrawn, placement of the endotracheal tube in the trachea
is confirmed, and the tube is secured. (See "Devices for difficult
endotracheal intubation in children", section on 'Flexible
fiberoptic bronchoscope'.) Fiberoptic intubation should be
considered in cases where the pre-intubation assessment suggests
that orotracheal intubation via RSI (preferred in most emergency
department intubation scenarios) is unlikely to be successful.
Examples include congenital airway anomalies such as micrognathia
or conditions where difficulty aligning the oral, pharyngeal, and
laryngeal axes is predicted (such as when neck mobility is
limited). The small size of the nasal passages in very young
children may preclude the nasal route for intubation.
In the hands of an experienced clinician, flexible fiberoptic
laryngoscopy is an excellent method for endotracheal intubation for
a patient with a difficult airway who is breathing spontaneously.
Availability of equipment and experienced personnel, as well as
time considerations, are usually the limiting factors for using
this technique for emergency airway management. Video laryngoscopy
Video laryngoscopes provide indirect laryngoscopy and display the
glottic view on a video monitor during endotracheal intubation.
Several devices are available in sizes appropriate for infants and
children. (See "Devices for difficult endotracheal intubation in
children", section on 'Video laryngoscope'.) Combitube The
Combitube is a dual-cuff, dual-lumen tube that is placed blindly in
the esophagus. The distal balloon is designed to occlude the
esophagus, while the proximal balloon will occlude the hypopharynx.
Positive pressure ventilation can be delivered through side ports
when the tube is in the esophagus, or through the tip when it is
placed in the trachea, which rarely occurs. Minimal training is
required to use the device effectively, and it can be placed
quickly, with minimal movement of the cervical spine [31]. The
Combitube does not provide a definitive airway. In addition, it is
only available in sizes appropriate for patients taller than 48
inches (1.2 m) [32]. (See "Emergency rescue devices for difficult
pediatric airway management", section on 'Combitube'.)
Complications may occur more commonly with the Combitube than with
an LMA [33]. Reported complications with the Combitube include
esophageal rupture, pyriform sinus perforation, and tongue
engorgement [34-36]. Mucosal ischemia may occur as the result of
pressure from the balloons [37]. Surgical airway Rarely,
noninvasive rescue devices fail to provide an airway. As a result,
emergency healthcare providers should be familiar with surgical
airway techniques, such as needle or surgical cricothyroidotomy,
although in reality few if any practitioners have enough
opportunity with these approaches to gain proficiency. Surgical
cricothyroidotomy should be avoided in infants and young children.
Equipment required for needle and surgical cricothyroidotomy,
particularly a setup for delivering transtracheal ventilation,
should be organized in advance and readily available in locations
where emergency airway procedures are performed. Step by step
instructions on how to perform needle or surgical cricothyroidotomy
and on how to perform percutaneous transtracheal ventilation are
discussed separately. (See "Needle cricothyroidotomy with
percutaneous transtracheal ventilation" and "Emergent surgical
cricothyrotomy (cricothyroidotomy)".) MANAGEMENT Anticipating and
preparing for advanced airway management, including intubation, for
a critically ill or injured child who may have a difficult airway
should begin before the patient arrives in the emergency
department. Emergency departments should have equipment and
supplies available in a readily identifiable location, such as a
"difficult airway box". (See 'Alternative airway techniques'
above.)
Once the child with a difficult airway is identified, a specific
plan for management must be developed that includes mobilizing
appropriate personnel and assembling specialized equipment
(algorithm 1 and algorithm 2 and algorithm 3). The child may
improve with supportive care and aggressive treatment of the
underlying condition. For children who require intubation, airway
management must include a rescue plan and preparation for a failed
airway (algorithm 4). Supportive care Care for all patients with
respiratory difficulties who may have a difficult airway should
include the following:
Provide supportive care and careful monitoring. Children who are
developing respiratory compromise must be rapidly identified. (See
"Initial assessment and stabilization of children with respiratory
or circulatory compromise".) Aggressively treat the underlying
condition. As an example, a patient with a congenitally abnormal
airway who develops croup should quickly receive nebulized
epinephrine and corticosteroids. In most cases, the child's
condition will improve and advanced airway management will not be
necessary. (See "Approach to the management of croup".) Avoid
situations that could worsen airway compromise. As an example, a
child with a retropharyngeal abscess who requires sedation for
imaging studies should receive reversible agents, whenever
possible. (See "Procedural sedation and analgesia in children".)
Anticipate the need for advanced airway management. Children with
conditions that rapidly and predictably progress to involve edema
and distortion of normal airway anatomy despite aggressive medical
management (such as thermal or chemical airway burns) should be
intubated early, in as controlled a setting as possible.
Airway management In the case of a predicted difficult airway,
the first intervention should be to call for help if such help is
available. The most expert physician available may be from
anesthesia or otorhinolaryngology rather than emergency medicine or
pediatrics, and they may provide valuable assistance in the rare
case of a difficult pediatric airway. An approach to management
decisions should consider the urgency of establishing an airway
("crash airway") and the likelihood that rapid sequence intubation
(RSI) will be successful. In comparison to adults, fewer
interventions are available for children who have a failed airway.
Crash airway Children who are in extremis are considered a "crash
airway" and should receive bag mask ventilation, followed by
orotracheal intubation (algorithm 3). Numerous studies have
demonstrated that effective BMV, especially in the prehospital
arena, is an effective means of supporting respirations [38,39].
BMV may provide oxygenation and ventilation as personnel and
equipment are being mobilized for endotracheal intubation, even in
situations with significant soft tissue obstruction such as
epiglottitis [40]. Alternative airway techniques (such as laryngeal
mask airway or needle cricothyrotomy) should be employed when
attempts to intubate the trachea are unsuccessful. (See
'Alternative airway techniques' above and 'Approach to the failed
airway' below.)
Rapid sequence intubation Rapid sequence intubation should be
considered for children who are not in extremis when the clinician
is confident that the child can be adequately ventilated with a bag
and mask and that oral tracheal intubation will be successful
(algorithm 1). Preparations should always be made for alternative
airway management (such as a laryngeal mask airway). (See "Rapid
sequence intubation in children" and 'Alternative airway
techniques' above.) Awake intubation Awake intubation, using
sedation and local anesthesia, is an approach that is frequently
used for adults [41]. With this technique, the patient is sedated
but not paralyzed and continues to breath spontaneously. There are
no reports describing experience with this technique for children
in the emergency department. It is likely that the degree of
sedation required to perform awake intubation in a frightened young
child would depress airway protective reflexes and spontaneous
respiration, placing the patient at risk for aspiration and
hypoxia. Alternative airway techniques Alternatives for airway
management when RSI or awake intubation are not feasible include a
laryngeal mask airway or fiberoptic intubation. (See 'Alternative
airway techniques' above and 'Approach to the failed airway'
below.) Approach to the failed airway A child with respiratory
failure for whom bag mask ventilation is not effective and the
trachea cannot be intubated has a failed airway. This situation is
often referred to as a "can't ventilate, can't intubate" scenario
[2]. Prompt intervention to improve oxygenation and ventilation is
essential (algorithm 4). The most expert clinician available should
be managing the airway. There is no evidence to guide
recommendations for management of these rare, but lifethreatening,
situations. Therefore, any intervention that could be possibly
helpful and is unlikely to worsen the patient's condition, should
be considered. An LMA should be used initially for most children
with failed airways who do not have complete airway obstruction.
Positive pressure ventilation through a device that is sealed
around the larynx may be effective for those with partial airway
obstruction, even if the obstruction is subglottic (such as with
croup or a subglottic foreign body). Temporary improvement in
oxygenation may be life-saving, while other interventions are
implemented. A surgical airway should be performed for a child with
a complete upper airway obstruction. Needle cricothyroidotomy is
recommended for children 10 years of age. A surgical airway should
also be considered for children with airway conditions that could
be worsened by injury from attempts to place an LMA (such as
expanding hematomas, significant midface trauma, or large
abscesses). (See "Needle cricothyroidotomy with percutaneous
transtracheal ventilation".) SUMMARY AND RECOMMENDATIONS Effective
airway management includes anticipating and planning for
difficulties. A reasonable, systematic approach for children can be
developed from experience with adult patients.
Problems with airway management can occur with positioning,
positive pressure ventilation, laryngoscopy, visualizing and/or
intubating the trachea, or identifying landmarks for performing a
surgical airway. (See 'Definition' above.) Conditions in children
that may make airway management difficult include characteristics
of the normal airway and congenital or acquired conditions. (See
'Causes of the difficult pediatric airway' above.) Airway
characteristics that may identify a difficult airway can be rapidly
assessed using the mnemonic LEMON (table 3). (See 'The LEMON
approach to difficult airway assessment' above.) L: Look externally
for indicators of a difficult airway E: Evaluate mouth opening,
thyromental distance, and the distance between the mandible and the
thyroid cartilage (figure 2) M: Mallampati score (figure 1) O:
Obstruction: Signs of airway obstruction N: Neck mobility
Alternative airway techniques that may be useful for managing a
difficult airway include a laryngeal mask airway (LMA), fiberoptic
laryngoscopy, video laryngoscopy, a lighted stylet, a combitube, or
performing a surgical airway. (See 'Alternative airway techniques'
above.) General management issues for all patients include
providing supportive care, monitoring, treating the underlying
condition, avoiding situations that could worsen airway compromise,
and anticipating the need for advanced airway management. (See
'Management' above.) Once the child with a difficult airway is
identified, a specific plan for management must be developed that
includes mobilizing appropriate personnel and assembling
specialized equipment (algorithm 1 and algorithm 2 and algorithm
3). The child may improve with supportive care and aggressive
treatment of the underlying condition. For children who require
intubation, airway management must include a rescue plan and
preparation for a failed airway (algorithm 4). We suggest that an
LMA be used as the initial rescue device for a child with a failed
airway who does not have complete upper airway obstruction or an
airway condition that could be worsened by injury from attempts to
place an LMA (Grade 2B). (See 'Approach to the failed airway'
above.) A surgical airway is the only option for a child who has a
failed airway with complete upper airway obstruction or an airway
condition that could be worsened by injury from attempts to place
an LMA. Children 10 years of age should receive a needle
cricothyrotomy. For children who are older than 10 years, the
surgical approach may be dictated by experience of the clinician.
(See 'Approach to the failed airway' above and "Needle
cricothyroidotomy with percutaneous transtracheal ventilation".) We
suggest that oxygen be delivered from a low pressure source when a
needle cricothyrotomy is performed (Grade 2C). Jet ventilation is
unlikely to improve ventilation and the risk of injury may be
significant.
Use of UpToDate is subject to the Subscription and License
Agreement.
Emergency airway management in the adult with direct airway
trauma Authors Trevor J Mills, MD, MPH Peter DeBlieux, MD Section
Editor Ron M Walls, MD, FRCPC, FAAEM Deputy Editor Jonathan
Grayzel, MD, FAAEM Disclosures All topics are updated as new
evidence becomes available and our peer review process is complete.
Literature review current through: feb 2012. | This topic last
updated: feb 9, 2012. INTRODUCTION Airway management in patients
who have sustained direct trauma to the airway is among the most
challenging problems for emergency clinicians. Blunt or penetrating
injuries to the head, oropharynx, neck, or upper chest can result
in immediate or delayed airway obstruction. Immediate, definitive
airway management is needed when the patient cannot protect their
airway or is unable to adequately oxygenate or ventilate. Emergent
or urgent airway management is indicated when a patient develops
respiratory distress or when symptoms are progressing rapidly. In
addition, airway management often is indicated when the patient
appears clinically stable, but the clinician anticipates clinical
decline (eg, smoke inhalation, edema, subcutaneous air, hematoma)
or feels that an unprotected airway presents a risk to the patient
who requires transport to another facility or to radiology for
extensive diagnostic studies. The higher rate of complicated
airways in this population mandates that the clinician be prepared
to use advanced airway techniques, including a surgical airway.
Airway assessment and management in adults with direct airway
trauma will be reviewed here. Other aspects of airway management,
including a general approach to the difficult airway, the decision
to intubate, and advanced tools for airway management, are
discussed separately. (See "The difficult airway in adults" and
"Rapid sequence intubation in adults" and "Devices for difficult
emergency airway management in adults" and "The decision to
intubate" and "Basic airway management in adults".) The general
management of trauma to the head and neck is also discussed
separately. (See "Facial trauma in adults" and "Penetrating neck
injuries" and "Skull fractures in adults".) CAUSES OF AIRWAY TRAUMA
Common causes of direct airway trauma include the following:
Blunt or penetrating maxillofacial injury Blunt or penetrating
neck injury Smoke inhalation or facial burns Caustic ingestion
Face and neck injuries from blunt or penetrating trauma can
cause severe bleeding into the oropharynx, expanding hematomas
within soft tissue, and disruption of bone and soft tissue. Smoke
inhalation, burns of the face and oropharynx, and caustic
ingestions are all capable of causing mucosal injury and severe
swelling and edema within the oropharynx, larynx, and
tracheobronchial tree. It is crucial that emergency airway managers
recognize that such injuries are dynamic and that conditions can
deteriorate quickly. Hematomas and soft tissue swelling can expand
rapidly, converting a partially obstructed airway into a completely
obstructed airway. The general management of the injuries listed
here is discussed separately. (See "Facial trauma in adults" and
"Penetrating neck injuries" and "Smoke inhalation" and "Emergency
care of moderate and severe thermal burns in adults" and "Caustic
esophageal injury in adults".) AIRWAY ASSESSMENT Determining the
need for immediate intervention The first step in managing patients
with direct airway trauma is to rapidly assess the patient and
their airway to determine whether a definitive airway is needed
emergently. Unresponsive patients and those with inadequate
respiratory function are intubated during or immediately following
evaluation. Patients in obvious respiratory distress also require
prompt intubation. This includes patients struggling to breathe
because of their injuries and those who have sustained severe burns
of the face or who demonstrate blistering or edema of the
oropharynx. Patients incapable of protecting their airway, as
demonstrated, for example, by inability to clear debris from the
oropharynx (eg, teeth, bone fragments, foreign bodies, emesis),
also require prompt intubation. A simple assessment consisting of
four basic questions often distinguishes patients requiring
intubation from those who may be observed. An affirmative answer to
any of the following questions identifies the need for intubation
in nearly all scenarios involving direct airway trauma:
Is there failure of airway maintenance or protection? Is there
failure of ventilation? Is there failure of oxygenation? Is
deterioration, particularly of the airway, anticipated? (ie, What
is the expected clinical course?)
This approach to intubation and management of the failed airway
is discussed in detail separately. (See "The decision to intubate"
and "The failed airway in adults".) Direct trauma to the airway can
cause conditions that deteriorate precipitously leading to complete
airway obstruction. Examples include expanding hematomas following
blunt or penetrating trauma and soft tissue swelling following
smoke inhalation or caustic ingestion. Of note, the progression of
an airway injury, such as a soft tissue hematoma, may involve the
deep tissue planes of the neck and therefore not become clinically
apparent until airway
obstruction is nearly complete and the chance for successful
intervention is slim. Therefore, the risk of rapid airway
compromise is a common and important reason for early intubation in
patients with direct airway trauma. Signs of airway compromise In
patients with direct trauma to the face, neck, or upper chest who
do not have a crash airway, the clinician performs a careful
examination looking for signs of airway compromise. These signs may
include any of the following:
Direct signs of airway compromise: Dyspnea Stridor Indirect
signs of airway compromise: Drooling Trismus Painful swallowing
(odynophagia) Tracheal deviation or other anatomical abnormality
involving the larynx or trachea Signs of developing airway
compromise: Nonsuperficial burns of the face or neck Severe
bleeding in the oropharynx or nasopharynx Subcutaneous air
(crepitus) in the neck or upper chest Hematoma in the neck or lower
face Hoarseness or other alterations in voice Subjective sense of
shortness of breath despite adequate oxygen saturation
If any such signs are identified, it is generally prudent to
secure the patient's airway early, before significant further
deterioration occurs. Of note, the signs listed above may not be
present during the clinician's initial examination. Frequent
reexamination is needed in patients who have sustained significant
direct trauma to the airway but whose airway is not secured early.
(See 'Patients appropriate for observation' below.) A subset of
initially stable patients is at higher risk of progressing to an
unstable and potentially difficult airway. Patients with any of the
following signs or conditions often require early intubation to
prevent subsequent airway compromise or collapse:
Unstable mandible or midface injuries Steady bleeding into the
oropharynx or nasopharynx Worsening or fluctuating level of
consciousness
Determining difficulty with management Emergency clinicians
should assess the patient's airway for potential difficulty with
bag-mask ventilation, endotracheal intubation, rescue device
placement, and cricothyrotomy. Mnemonics that can be used for
these
assessments are provided here and discussed in detail separately
(table 1 and table 2 and table 3 and table 4). (See "The difficult
airway in adults".) [1]. Difficulty with bag-mask ventilation
should be anticipated in patients who have sustained severe
maxillofacial injuries that disrupt bones and create instability or
disfigurement in the middle or lower face. Such injuries make it
difficult to maintain a proper mask seal. Obstruction from heavy
bleeding, soft tissue swelling, or hematoma can interfere with
effective bag-mask ventilation. Posterior displacement of severe
fractures of the maxilla or mandible can also obstruct the
patient's airway [2]. Subcutaneous air in the neck or communicating
injury that establishes an external opening from any part of the
airway (mouth, oropharynx, larynx, trachea) makes bag-mask
ventilation impossible and also increases the likelihood that
bag-mask ventilation will further distort anatomy, making
subsequent airway rescue maneuvers more difficult. Bleeding and
disruption of normal anatomy can make laryngoscopy and intubation
extremely difficult. Mouth opening may be limited and should be
carefully assessed with the anterior portion of the cervical collar
removed. Bleeding, soft tissue swelling, and debris can obscure the
view of the glottis during laryngoscopy, making effective suction
essential. In-line stabilization of the neck is recommended in all
blunt trauma patients during intubation, although it increases the
difficulty of the procedure. In penetrating trauma, the role of
in-line stabilization is controversial. Victims of isolated
penetrating trauma who are neurologically intact rarely have
unstable bony spinal columns and so are at low risk of sustaining a
spinal cord injury during intubation [3]. However, a patient with
penetrating injury may have concomitant blunt injury. Examples
include a patient who is shot then falls down a flight of stairs or
a patient who sustains a stab wound to the neck while also being
beaten about the head and neck with blunt objects. Although in-line
stabilization should be maintained if the clinician harbors any
doubt about spinal column injury, the risk of unstable bony injury
is so low in isolated penetrating injury with intact neurological
examination that, if the operator is unable to see the glottis
satisfactorily to intubate, it may be preferable to relax spinal
immobilization somewhat to achieve a gentle intubation rather than
allow hypoxemia to occur. Judgment is required to determine which
of the two threats (hypoxemia caused by a failed airway versus
spinal cord injury caused by spinal column movement) represents a
more realistic or serious risk to the patient. Placement of a
rescue device (eg, laryngeal mask airway) can be difficult if mouth
opening is limited, if the airway is disrupted or distorted (eg, by
swelling), or if debris such as teeth or bone fragments are
present. Cricothyrotomy can be difficult if normal anatomic
relationships are disrupted or a hematoma is present at the
anterior neck. MANAGEMENT
Guiding principle: Secure the airway early Injuries sustained
from direct trauma to the airway are often dynamic and conditions
can deteriorate quickly [4]. As examples, hematomas and soft tissue
swelling can expand rapidly, converting a partially obstructed
airway into a completely obstructed airway. Signs suggestive of
imminent obstruction are described above. (See 'Signs of airway
compromise' above.) It is best to secure the airway early whenever
signs of active or impending obstruction are identified or there is
doubt about the extent of the injuries or their likely course.
Doing so enables clinicians to secure the airway under relatively
controlled circumstances before complete obstruction occurs and a
crisis ensues. The basic and advanced techniques used to manage the
airway are discussed separately. (See "Rapid sequence intubation in
adults" and "The difficult airway in adults" and "Basic airway
management in adults" and "Devices for difficult emergency airway
management in adults".) Crash airway: No time available Patients
with direct trauma to their airway may present in extremis,
unresponsive to the examiner and without effective ventilation or
circulation (ie, crash airway). The basic approach to the crash
airway remains unchanged in such patients. Algorithms outlining the
basic approach to the traumatized airway and the crash airway are
provided (algorithm 1 and algorithm 2). The airway management
algorithms are discussed in detail separately. (See "Advanced
emergency airway management in adults" and "The failed airway in
adults".) Management of the patient with an exposed trachea, most
likely from a stab wound to the neck or a "clothesline" type
injury, differs from the standard management of a crash airway. In
such a circumstance, the airway manager prevents the inferior
portion of the trachea from retracting into the chest by grasping
it with a towel clip or clamp and the exposed trachea is then
intubated directly. The general management of penetrating neck
wounds is discussed separately. (See "Penetrating neck injuries".)
Time available and difficult airway anticipated The difficult
airway algorithm provides the fundamental approach to the patient
with direct airway trauma who requires intubation and whose airway
is anticipated to be difficult (algorithm 3 and algorithm 1). The
specific approach selected is determined by the patient's injuries,
patient attributes that suggest difficult airway management, the
skills of the airway manager, and the resources available. The
traumatized airway can be difficult to manage and it is important
to obtain whatever help is available. The general approach to the
difficult airway is discussed separately; aspects of management
related to the traumatized airway are discussed below. (See "The
difficult airway in adults".) The most important questions to ask
when faced with a traumatized airway (or any difficult airway)
are:
Is there time? In other words, can the patient's oxygen
saturation (SpO2) be maintained above 90 percent? Is difficulty
with bag-mask ventilation (BMV) anticipated?
If the SpO2 can be maintained above 90 percent, there is some
time to consider different approaches and to make preparations. If
adequate oxygenation cannot be maintained, a failed airway is
present, and a definitive airway must be established promptly
(algorithm 4). (See "The failed airway in adults".) If the SpO2
remains above 90 percent and no risk factors for difficult BMV are
identified, the clinician may elect to use standard rapid sequence
intubation (RSI) to secure the airway. If difficult BMV is
anticipated, RSI may pose risks, and an awake approach to
intubation may be best. Alternatively, RSI may be undertaken using
a "double set-up" in which the patient undergoes RSI with one or
two brief attempts at laryngoscopy, proceeding directly to a
cricothyrotomy if intubation is not possible. Both the intubation
and the cricothyrotomy are prepared for in advance. (See "Rapid
sequence intubation in adults".) Of note, subcutaneous emphysema
usually represents a contraindication to BMV because gases forced
into the airway during BMV can expand the neck's soft tissues,
compromising subsequent efforts to ventilate or to intubate. In
patients with very minimal detectable subcutaneous air, gentle,
controlled bag-mask ventilation might be attempted, but its
effectiveness is not assured and it should be abandoned if the
subcutaneous air increases in volume. The awake approach to
securing the airway involves sedation to the level used for common
emergency department procedures (eg, using propofol or ketamine) in
conjunction with topical airway anesthesia (eg, using atomized or
nebulized lidocaine, or lidocaine paste or jelly). This approach
allows the patient to continue to breathe spontaneously while
sedation and topical anesthesia enable the clinician to overcome
the patient's protective airway reflexes. Excessive blood or
secretions in the airway limit the effectiveness of topical
anesthetics and may preclude use of the awake approach if
adequately deep sedation without topical anesthesia cannot be
achieved. (See "The difficult airway in adults", section on 'Awake
look'.) The awake but sedated patient can undergo standard direct
laryngoscopy, video laryngoscopy, or fiberoptic laryngoscopy. The
presence of a large amount of upper airway blood will likely make
flexible fiberoptic laryngoscopy difficult or impossible. If the
vocal cords are visualized, the clinician can opt to intubate
during the awake look without additional medications or to withdraw
the laryngoscope and perform standard RSI. We believe in general it
is best not to remove the laryngoscope and perform RSI in a patient
with direct airway trauma due to the risk of the glottic view
deteriorating during the interim. Direct, fiberoptic, and video
laryngoscopy are the primary awake intubation techniques used in
the setting of the traumatized airway. Flexible fiberoptics require
patient stability, time, and operator expertise. Rigid fiberoptic
devices (eg, optical stylet) may enable clinicians to obtain a more
rapid view of the glottis. Copious blood or secretions in the
airway can make fiberoptic laryngoscopy difficult or impossible.
Devices used for difficult
airway management are discussed separately. (See "Devices for
difficult emergency airway management in adults".) In some
instances the clinician will judge RSI to be the best approach
despite the presence of a potentially difficult airway,
particularly if performed early before significant deterioration
occurs (ie, when the anatomy is still close to normal). Several
observational studies suggest that RSI is effective in patients
with traumatized airways [5,6]. An approach incorporating a double
set-up is often prudent when