Management of the Difficult Airway Alternative Airway Techni

8/13/2019 Management of the Difficult Airway Alternative Airway Techni

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Management of the difficult airway:

alternative airway techniques and adjuncts

Kenneth H. Butler, DO, FACEPa,*, Brian Clyne, MDb

aEmergency Medicine Residency Program, Division of Emergency Medicine,

Department of Surgery, University of Maryland School of Medicine,419 West Redwood Street, Suite 280, Baltimore, MD 21201, USA

bDivision of Emergency Medicine, Brown University School of Medicine,

593 Eddy Street, Samuels 2, Providence, RI 02903, USA

Management and stabilization of the airway is the single most important

procedure in emergency medicine and truly defines the specialty. No other

organ system can be resuscitated successfully without its securement.

Emergency physicians are frequently called on to provide expeditious

airway interventions for patients in extremis, many of whom have acuterespiratory deterioration and airway compromise under the most difficult

circumstances. Failure to secure a patients airway can lead to permanent

neurologic damage or death in a matter of minutes. Often, little time is

available to obtain an adequate patient history or to prepare the patient

as in conventional airway management. Accordingly, the few seconds or

minutes spent in evaluation, planning, and preparation for such scenarios

can make the difference between life and death. To provide optimal care

under these circumstances, the emergency physician must be skilled in a

variety of methods in airway management and have the proper equipmentand devices available at all times.

As the specialty of emergency medicine matures, physicians are becoming

increasingly proficient in airway management and are relying less frequently

on assistance from other medical specialties [1]. Despite this trend, a national

survey of emergency medicine residency training programs showed that only

half of these programs provided any experience with an alternative device

and little training in nonsurgical approaches to the difficult airway [2]. Many

emergency physicians thus graduate from residency programs with in-

adequate training in the management of a difficult airway. Residency

Emerg Med Clin N Am

21 (2003) 259289

* Corresponding author.

E-mail address: [email protected] (K.H. Butler).

0733-8627/03/$ - see front matter 2003, Elsevier Inc. All rights reserved.

doi:10.1016/S0733-8627(03)00007-5


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workshops on airway management tend to focus on standard laryngoscopic

procedures and seldom cover alternative methods for managing a difficult

airway. As a result, most graduating physicians are more competent in estab-lishing a surgical airway than in applying alternative nonsurgical airway

skills, even though new Advanced Cardiac Life Support (ACLS) guidelines

include the laryngeal mask airway (LMA) and esophageal-tracheal Com-

bitube (ETC) as better alternatives to facemask ventilation and as accept-

able alternatives to tracheal intubation [3].

Despite technologic advances and the development of new devices for

airway management, rapid-sequence intubation (RSI) remains the standard

of care in the practice of emergency medicine. Direct laryngoscopy remains

almost exclusively the manner in which all emergency airways are secured.Numerous emergency department (ED) case series and multicenter studies

have shown intubation success rates at or greater than 98% using RSI and

direct laryngoscopy. Standard laryngoscopic intubation, however, may not

provide a definitive airway in every patient with a difficult airway. Instead of

repeating the standard approach and increasing complications, the clinician

should consider an alternative device or method of securing the airway.

Furthermore, clinical pathways for controlled situations, such as the awake

intubation arm of the American Society of Anesthesiologists difficult airway

algorithm (Fig. 1) [4,5], are not applicable to the acuity of the ED patientwho is agitated, hypoxic, and traumatized, with bloody secretions and

vomitus. As these patients tend to be our difficult airways, reliance on

preparation, prediction, evaluation, and familiarity with an alternative

airway management device will increase our rate of successful intubation.

The incidence of difficult intubations in the ED cannot be extrapolated

from the anesthesiology literature. It seems reasonable to expect that difficult

airways will be more frequent in EDs than in operating rooms, given the

urgent need for the procedure and the lack of preparation of the patient [6].

When assessing a patient in need of airway support, the emergency physicianfirst should attempt to identify clinical clues that suggest the presence of

a difficult airway and, when appropriate, select an alternative device. This

strategy can prevent a patients deterioration or demise caused by multiple

attempts using standard methods. Alternative devices and techniques include

the laryngeal mask airway, dual-lumen devices, tracheal introducers,

transillumination intubation, flexible fiberoptic scopes, and semi-rigid stylets.

Fig. 1. Difficult airway algorithm. *Nonsurgical tracheal intubation choices consist oflaryngoscopy with a rigid laryngoscope blade (many types), blind orotracheal or nasotracheal

technique, fiberoptic/stylet technique, retrograde technique, illuminating stylet, rigid broncho-

scope, and percutaneous dilational tracheal entry. Always consider calling for help (eg,

technical, medical, surgical) when difficulty with mask ventilation or tracheal intubation is

encountered. ++Consider the need to preserve spontaneous ventilation. FromBenumof J. The

laryngeal mask airway and the ASA difficult airway algorithm. Anesthesiology 1996;84:68699;

with permission.

c

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261K.H. Butler, B. Clyne / Emerg Med Clin N Am 21 (2003) 259289


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The American Society of Anesthesiologists Task Force on Management of

the Difficult Airway defines a difficult airway as a clinical situation in

which a conventionally trained anesthesiologist experiences difficulty withmask ventilation, difficulty with tracheal intubation, or both [7]. The task

force defines difficult mask ventilation as occurring when it is not possible to

maintain the PO2[ 90% using 100% oxygen and positive pressure mask

ventilation, and difficult intubations as occurring when more than three

attempts are required using conventional laryngoscopy. Despite careful

preprocedure evaluation, airway management difficulties may not be pre-

dicted in some cases; therefore, strategies for managing the unanticipated dif-

ficult airway should be formulated and practiced. The A in the ABCs also

can represent an alternative device in airway management.

Prediction of the difficult airway

One single preprocedural indicator specifically for determining a difficulty

in ventilation, laryngoscopy, or intubation has not been found. The grading

tools used by anesthesiologists provide accuracy in the preoperative as-

sessment of stable patients. In contrast, emergency patients are difficult to

assess. They are acutely decompensating, have a low margin for safety,

hypoxemia, hypertension, hypotension, and other stressors, and require

rapid intubation under suboptimal conditions. Often they are in extremis,

agitated, and combative, have facial or laryngeal trauma, full stomachs, and

cervical immobilization, and are unable to speak, making any assessment

extremely difficult.

Some predictors have proven consistently useful; combinations of

predictors are the most sensitive. The most used predictive scheme for

airway assessment in anesthesiology is the Mallampati classification. This

system assigns three gradations based on increasing difficulty in visualizing

the posterior pharyngeal structures to predict difficult laryngeal exposure

(Box 1) [8]. Samsoon and Young modified the Mallampati scoring system

Box 1. Mallampati airway classification system

Class I Soft palate, fauces, uvula, anterior and posterior tonsillar

pillars are visible

Class II Soft palate, fauces, uvula are visible

Class III Soft palate, base of uvula are visibleClass IV Soft palate not visible at all

Reproduced with permission from Deem S, Bishop MJ: Evaluation and

management of the dicult airway. Crit Care Clin 1995; 11:127 (citing Mallampati

SR, Gatt SP, Gugino LD, et al. A clinical sign to predict dicult tracheal intubation:

a prospective study. Can Anaesth Soc J 1985;32:42934.)



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into four classes; increasing class number suggests greater difficulty in glottic

exposure (Fig. 2) [9]. This predictive score evaluates the size of the tongue in

relation to the oropharynx, which indicates the ease or difficulty of achievingoptimal visualization. Airway assessment scoring systems have been based

on variables such as the evaluation of mouth opening, jaw size, thyromental

distance, and cervical range of motion, each individually having limited

sensitivity and specificity. Combining scoring systems provides better

prediction. The Rule of Threes offers the simplest predictor at the bed-

side. If the examiner can place three finger breaths (approximately 67 cm)

between the upper and lower teeth, between the mandible and the hyoid

bone, and between the thyroid cartilage and the sternal notch, direct

laryngoscopy is usually successful [10]. Significant difficulty with two ormore of these components justifies a more detailed assessment, because the

probability of difficulty increases threefold. Predictors of difficult bag-valve-

mask (BVM) ventilation (ie, high body mass index, advancing age, presence

of a beard, lack of teeth) also should be factored into a prediction, because

recent evidence suggests the incidence of failure with this technique may be

higher than previously believed [11]. In the presence of predictors of airway

difficulty, the use of an alternative device should be anticipated.

Preparation

The frequency of failed intubations in the emergency department is

approximately 1 in 500 [12]. The single most important factor in dictating

the success or failure of airway management remains the skill level of the

airway manager. The intubating physician must be familiar with various

types of airway equipment and must select and apply the appropriate device

Fig. 2. Samsoon and Young modification of Mallampati classification, evaluating relative size

of oropharyngeal structures to predict difficulty in laryngeal exposure during direct

laryngoscopy. Higher class number suggests greater difficulty in glottic exposure. From

Samsoon GLT, Young JRB. Difficult tracheal intubation. Anaesthesia 1987;42:48790; with

permission.



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or technique for every airway resuscitation. Knowledge of and skill main-

tenance for plan B strategies prepares the intubator for difficult cases

and facilitates establishment of a stable airway if initial intubation attemptsfail. The airway manager must check all airway equipment personally

before each emergency department shift. Equipment should be arranged

in an easily accessible order at the head of the bed.

Prehospital intervention

The difficult airway may first declare itself in the field when emergency

medical services (EMS) personnel report that multiple attempts using

standard laryngoscopic techniques failed, that the patient remained agitated

and combative because of hypoxia, or that intravenous (IV) access could not

be established. Although paramedics are well trained in airway management

and frequently respond to patients in respiratory distress, one fourth of

endotracheal tubes (ETTs) inserted by prehospital personnel in urban EMS

systems are misplaced [13]. All patients intubated in the field must have their

airway reassessed in the ED. Direct laryngoscopic confirmation of ETT

placement and use of a colorimetric or end-tidal carbon dioxide (ETCO2)

detector should be first priorities on arrival. Pediatric patients may not

benefit from endotracheal intubation if BVM ventilation can be performed

properly by EMS personnel. The addition of out-of-hospital endotracheal

intubation (ETI) to a paramedic scope of practice that already included

BVM ventilation did not improve survival or neurologic outcome of

pediatric patients in an urban EMS system [14]. A detailed mental picture

of the patients condition and stability of the airway conveyed by radio

transmission should help ED personnel prepare the resuscitation room

before the patients arrival.

The risk for intubation failure increases if the resuscitation room

equipment is not inventoried properly and checked routinely for proper

function. The simple mnemonic S-O-A-P-ME [15] should be used in the

anticipatory phase and facilitates a clean intubation: S suction,

O oxygen, A airway equipment, P pharmacologic agent, ME

monitoring equipment. In this phase, the intubator checks the suctioning

device and connection, selects the appropriate BVM and attachment to a wall

oxygen source, verifies illumination of the laryngoscope blade, ensures

accessibility of sedation and paralytic drugs, and prepares all mechanical

monitoring equipment.

Initial evaluation

On arrival at the ED, all patient moorings should be checked, secured,

and transferred to a permanent source. A second IV line should be

established, as many placed in the field have been infiltrated or lost as a result



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of physical movement. Patients should be rehydrated, as their insensible

water loss has been increased by tachypnea. Adults should receive a liter

of normal saline before intubation if their cardiopulmonary status per-mits. Fluid administration may decrease the incidence of postintubation

hypotension caused by the change from negative intrathoracic pressure to

the positive intrathoracic pressure of mechanical ventilation. The decrease in

venous return associated with an increase in intrathoracic pressure leads to

a decrease in cardiac output and a subsequent decrease in blood pressure

[16]. The patients anatomic airway should be evaluated in tandem with

physiologic monitoring.

In 1993, the American Society of Anesthesiologists published an

algorithm for management of difficult intubations in the operating room[4]. An update published in 1996 (Fig. 1) incorporates the laryngeal mask

airway. As in preprocedure assessments, this algorithm for stable patients

may not be applicable to the practice of emergency medicine. In the ED,

intubation is conducted to secure the airway and prevent the underlying

condition from causing rapid deterioration. Obstruction, trauma, altered

level of consciousness, respiratory and pulmonary failure, or underlying

shock does not allow the option of bringing the patient out of anesthesia to

resume spontaneous ventilation or awakening the patient if difficulty is

encountered, as recommended in the algorithm. In addition, the ASAsuggestion to cancel the case and regroup may not be realistic for

emergency medicine physicians, especially those in community hospitals.

Emergency physicians must optimize their first attempt at intubation. If

failure is inevitable, they must provide proper BVM ventilation and be

skilled in at least one alternative device for securement of the airway.

Aids to ventilation

The laryngeal mask airway

The laryngeal mask airway (LMA) (North America, Inc., San Diego,

CA) is an innovative airway management device intended as an alternative

to facemask use. For ventilation, the LMA is more effective than a BVM

alone in anesthetized patients, because BVM ventilation often requires two

hands to maintain a good seal [17]. The LMA provides an effective

emergency airway in a variety of crisis situations. For anesthesiologists and

anesthetists, the LMA is likely the most familiar first option in the algorithm

for managing a difficult airway (Fig. 3) [5].The LMA consists of a semirigid tube attachment and an inflatable mask

that is placed into the hypopharynx and advanced over the larynx. When

inflated, the mask cuff provides a seal around the glottic aperture (Fig. 4)

[18]. The LMA is available as a reusable latex-free device and as a disposable

one. Sizes range from those appropriate for neonates to large adults. If

endotracheal intubation has failed, the LMA may be successful [4].



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Insertion technique

The LMA lies in a supraglottic position in the hypopharynx, and its ease

of insertion is usually independent of anatomic and pathologic factors

associated with the difficult airway (Box 2). Placement of the LMA is

unrelated to the Mallampati [23], Cormack, and Lehane scores, and is

unaffected by manual inline stabilization or the presence of a rigid cervical

collar [24].

Once the LMA is inserted, its aperture is lined up anatomically with the

glottis, which makes it useful as an aid to intubation while giving oxygenand monitoring ventilation by way of capnography (Fig. 5). Hypoxic

damage resulting from persistent conventional attempts to intubate a

cyanotic patient may be avoided. Cricoid pressure can be maintained with

the LMA in situ [25]. Once hypoxia is resolved, an alternative technique can

be considered if the need for endotracheal intubation remains (eg, use of

a flexible fiberoptic scope).

Indications and advantages

When a surgical airway is being considered, an attempt to ventilate withthe LMA may be beneficial simply because it usually can be inserted within

Fig. 4. The components of the laryngeal mask airway. From LMA North America, Inc., San

Diego, CA; with permission.

Fig. 3. The laryngeal mask airway (LMA) fits into the ASA algorithm on the management of

the difficult airway in five places, as an airway (ventilatory device) or a conduit for a fiberscope.

From Benumof J. The laryngeal mask airway and the ASA difficult airway algorithm.

Anesthesiology 1996;84:68699; with permission.

b



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Fig. 5. Dorsal view of the laryngeal mask airway, showing position in relation to pharyngeal

anatomy.FromLMA North America, Inc., San Diego, CA; with permission.

Box 2. Primary advantages of the laryngeal mask airway in

management of the difficult airwayReliance on direct visualization of the cords for successful airway

control is obviated [19,20].

Neuromuscular blockade is not required for insertion and

function (but obtunded airway reflexes are required) [20].

The LMA usually can be inserted readily despite abnormal

supraglottic anatomy. [19,21] It is not recommended for

patients with acute epiglottitis. Intraglottic problems may

impede LMA effectiveness after placement.

The LMA can be used alone or as an aid to endotrachealintubation [20,22].

Adapted from Pollack CV Jr. The laryngeal mask airway: a comprehensive

review for the emergency physician. J Emerg Med 2001;20(1):5366.



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a few seconds and the first-pass success rate is high [26]. In cardiopulmonary

resuscitation, the LMA has been used successfully by physicians, nurses,

and paramedics [2729]. Its insertion is independent of anatomic featuresused to predict or score difficult intubation and is not impeded by manual in-

line cervical immobilization or a rigid collar [30]. It can even be inserted in

prone patients and those with otherwise inaccessible airways [31,32]. The

LMA has demonstrated usefulness for difficult airway management in

children and adults. The Pediatric Emergency Medicine Committee of the

American College of Emergency Physicians advocates the LMA as the

optimum alternative when RSI is unsuccessful [33].

The success rate of the application of the LMA depends on the operators

familiarity with the device. The standard LMA may be used as a conduit forpassing an ETT by way of a gum elastic bougie, flexible fiberoptic scope, or

lighted stylet, but its use as an adjunct for these procedures is expected to

decline now that the intubating LMA is available [3436]. The LMA also

may be a conduit for the administration of resuscitation medication.

Epinephrine and aerosolized albuterol have been delivered successfully by

way of the LMA [37,38].

Contraindications and disadvantages

The most important issue mitigating use of the LMA in the ED is the riskfor aspiration of gastric contents. Unlike an ETT with an inflated cuff, the

ventilating device does not physically separate the respiratory and alimentary

tracts [39]. Another contraindication to the use of the LMA for ventilation is

the need for high pulmonary inflation pressures because of increased airway

resistance or very low lung compliance. Inadequate ventilation because of air

leakage and gastric distention are the predictable adverse effects of

attempting positive-pressure ventilation in tight asthmatics.

The primary limitation of the LMA is the concern over incomplete

protection of the airway. This should not be considered an absolute con-traindication to its use because a living patient with aspiration pneumonitis

is preferable to a patient dead for lack of an airway.

The primary concerns about use of the LMA are (1) the risk for gastric

insufflation, (2) the potential for inadequate ventilation because of sub-

optimal positioning, and (3) the inability to generate high inflation pressures

in bronchospastic patients. Table 1 compares the LMA with other means of

ventilation in patients with difficult airways.

The intubating LMA

The intubating LMA (ILMA) (LMA-Fastrach, Gensia Automedics, San

Diego, CA) was designed specifically for blind tracheal intubation. The

ILMA functions as an airway in the same fashion as the LMA. Its shorter,

wider ventilating conduit makes the ILMA easy to pass or withdraw over

a translaryngeal tube.



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Insertion technique

A redesigned, tapered tracheal tube is passed blindly through the ven-

tilating airway (Fig. 6). The orotracheal tube can be as large as 8 mm. TheILMA has a flat metal handle that projects posteriorly. This allows the intu-

bator to stand above the head of a supine patient and reposition the ILMA

for blind attempts to pass the tracheal tube.


The ILMA is indicated in anticipated or unexpected difficult airway

situations and for use as a guide for intubation of the trachea. Similar to the

LMA, the ILMA does not reliably protect the airway from regurgitation and

aspiration, but in the emergency pathway of cannot intubate, cannotventilate, the risk for aspiration must be weighed against the potential for

establishing an airway. Burgoyne and Cyna compared the ILMA and LMA

for ease of insertion and successful ventilation when used by inexperienced

resuscitators (nonanesthetic personnel). There were no clinically relevant

differences in the mean time to airway insertion (within 2 minutes), successful

ventilation, or expired tidal volume [40]. Emergency physicians using the

Table 1

Comparison of laryngeal mask airway (LMA) with other approaches for difficult or failed

airways

Characteristic

ET

intuba-

tion

LMA/

intubating

LMA BVM CombitubeLighted

stylet

Fiber-

scope

Surgical

airway

Avoidance of

laryngoscopy

0 ++++ ++++ ++++ +++ ++ ++++

Avoidance of

esophageal

intubation

++ ++++ ++++ + ++ ++ +++

Ease of placement ++ +++ +++ +++ ++ + +

Allows ventilation

without intubation

0 ++++ ++++ +++ NA 0 NA

Patient tolerance + +++ +++ + + ++ +

Cardiovascular/

sympathetic

response

++ +++ ++++ ++ ++ +++ +++

Aspiration risk ++ +++ ++++ ++ ++ ++ +++

PPV requirement ++++ ++ +++ +++ NA NA ++++

Security of airway ++++ +++ + ++ NA NA +++

Use with distorted

facial anatomy

++ ++++ + ++ + + +++

Pediatric use ++++ ++++ +++ 0 0 ++ +

Anesthetic depth +++ +++ + ++++ +++ ++ NA

Learning curve + +++ +++ ++++ ++ + +

Abbreviations: BVM, bag, valve, mask; NA, not applicable; PPV, positive pressure

ventilation.

FromPollack CV Jr. The laryngeal mask airway: a comprehensive review for the emergency

physician. J Emerg Med 2001;20:5366.



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ILMA for the first time achieved ventilation in less than 15 seconds and

tracheal intubation in less than 1 minute [41]. In a large study involving 245

patients with difficult airways (ie, patients with Cormack-Lehane grade 4

views, immobilized cervical spines, airways distorted by tumors, surgery, or

radiation therapy, or wearing sterotactic frames), insertion of the ILMA was

accomplished in three attempts or fewer. The overall success rates for blindand fiberoptically-guided intubation through the ILMA were 96.5% and

100%, respectively, suggesting the device is useful in the emergent treatment

of patients for whom intubation with standard rigid laryngoscopic failed

[41,42]. The ILMA also has been compared with fiberoptic intubation for

management of the difficult airway and proved to have a high success rate and

a comparable time to achieve tracheal intubation [43]. The ILMA also may be

used in children who weigh more than 30 kg (Table 2). Most investigators

agree that proficiency in use of the ILMA requires practice in a controlled

setting before it can be used successfully under emergent circumstances.

Fiberoptic intubation

Flexible fiberoptic intubating scopes have become more advanced and

geared to use in the emergency setting. Scopes have become smaller in

diameter, compared with those used by pulmonologists, and completely

Fig. 6. Insertion technique for intubating laryngeal mask airway (LMA-Fastrach). If no

resistance is felt, continue to advance the ETT while holding the LMA-Fastrach steady until

intubation has been accomplished. From Gensia Automedics, Inc., San Diego, CA; with

permission.



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portable. Their built-in battery light source eliminates the time-consuming

setup and connection to a bulky power source.

Fiberoptic intubation, like all alternatives to RSI, has a place in airway

management for selected patients. Awake intubation benefits patients withmarked laryngeal or cervical pathology, for whom paralysis and suppression

of the respiratory drive or insertion of a laryngoscope blade may be detri-

mental. A study of more than 13,000 intubations demonstrated that a simple

algorithm for endotracheal intubation confined to only two methods (con-

ventional or fiberoptic intubation) is reliable, successful (failure rate,

0.045%), and easy to learn [44].

Insertion technique

The nasotracheal approach to the airway with a flexible fiberoptic scopeis often simpler than the oral approach because the instrument is aimed

directly at the glottis as it emerges from the nasopharynx into the hypo-

pharynx. Intubation over a fiberoptic scope can be performed successfully

through an LMA and around the ETC.


There are many advantages to the use of this technique, including

application to all age groups, excellent airway visualization, ability to in-

sufflate oxygen during the procedure, high success rate, and immediate con-firmation of ETT placement [45].


There may be difficulty in the use of a fiberoptic scope in the emergency

setting. The presence of uncontrolled secretions, mucus, or active bleeding

markedly impairs visualization. Suction through these instruments is

Table 2

Larynegeal mask airway (LMA) and intubating LMA sizes and maximum cuff inflation

volumes

Mask

size

Patient

description

Available in

LMA-ClassicRM

Available in

LMA-Unique

(disposable)

Available in

LMA-Fastrach

(intubating LMA)

Max. cuff

volume (cc)

1 Infants up to 5 kg X 4

1.5 Infants 510 kg X 7

2 Infants and

children 1020 kg

X 10

2.5 Children 2030 kg X 14

3 Children 3050 kg X X X 20

4 Adults 5070 kg X X X 30

5 Adults 70100 kg X X X 40

6 Large adults >100 kg X 50

FromPollack CV Jr. The laryngeal mask airway: a comprehensive review for the emergency

physician. J Emerg Med 2001;20:5366.



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ineffective. Attaching an oxygen source to the suction channel may increase

the field of view by blowing away offending secretions or debris. Advance-

ment of the ETT over the fiberoptic scope may be difficult, as the bevel ofthe tube may catch on the arytenoids, cartilages, or aryepiglottic folds.

Withdrawing and rotating the ETT 90 and readvancing or changing to

a smaller tube usually solves this problem.

In a study of 60 consecutive intubations using a flexible fiberoptic

nasotracheal technique, the failure rate was 13% and bleeding occurred

in 22%, demonstrating its limitations [46]. Other emergency department

studies have shown that immediate airway control is often difficult with

fiberoptic-aided endotracheal intubation; therefore, the technique should be

used only in selected patients [47]. In a study of ED practices at U.S.teaching hospitals, Levitan found that fiberoptic intubation was seldom

used as a means of managing the difficult airway [2].

Barriers to the selection of flexible fiberoptic intubation include the

following: (1) it is not standard equipment in most emergency departments,

(2) an initial training period is required, (3) the learning curve is steep, and

(4) skills decay because the procedure is used so infrequently.

Combitube

The esophageal-tracheal Combitube (ETC) (Combitube, Kendall-

Sheridan Catheter Corp, Argyle, NY) is a blindly inserted, double-lumen

tube designed to facilitate ventilation during cardiopulmonary resuscitation

(CPR) [12]. Its predecessor, the esophageal obturator airway (EOA), led

to complications such as esophageal rupture and tracheal obstruction,

prompting an improved design [48]. The ETC combines the concept of the

EOA with that of the ETT. The device consists of two lumens:

a pharyngeal lumen and a tracheal lumen separated by a partition

wall. One lumen has an open distal end, similar to an ETT, and the other isclosed at the distal end, with multiple ventilating eyes proximal to its

inflatable cuff. A second larger oropharyngeal balloon inflates to secure the

ETC in position. Because ventilation is possible through either lumen, the

Combitube can be used after esophageal or tracheal insertion (Figs. 7, 8).

The device comes in two sizes: a 41 Fr for adult males and a 37 Fr

(Combitube SA) for women and small adults.

Insertion technique

The ETC was designed to be inserted blindly; however, some investigatorsrecommend use of a laryngoscope to limit trauma and facilitate insertion

[48,49]. While grasping the patients tongue and jaw between the thumb and

forefinger, the clinician inserts the device to a depth at which the two black

ring markers are between the front teeth or alveolar ridges. With blind in-

sertion, there is a high probability the distal tip will enter the esophagus [48].

The oropharyngeal balloon is then inflated with 100 mL of air using the large



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prepackaged syringe. This seals the tube in the posterior pharynx, limiting

aspiration of oral contents and minimizing movement. Next the esophageal

cuff is inflated with 15 mL of air, sealing the esophagus. Ventilation should beattempted first through the pharyngeal lumen and the chest auscultated for

breath sounds. If breath sounds are absent or end-tidal CO2 is not present, the

distal tip was blindly inserted into the trachea and the patient should be

ventilated through the tracheal lumen and the chest again auscultated for

breath sounds. Tube placement can be confirmed by conventional means

such as auscultation, end-tidal CO2, and self-inflating bulb [50,51].

Fig. 7. The Combitube in the esophageal position. Reproduced with permission from

Combitube and Combitube SA (Small Adult) dual-lumen airways; Kendall, a unit of Tyco

Healthcare Group, LP, Mansfield, MA.



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Indications and advantagesThe Combitube is indicated as an alternative to endotracheal intubation

(ETI) for medical personnel unskilled in airway management. As such, it is

best suited for the prehospital setting, where patient positioning and

environmental conditions may preclude laryngoscopy. For those skilled in

airway management, the main indication for the Combitube is as a rescue

device for the failed airway or the cannot intubate, cannot ventilate sce-

nario in which cricothyrotomy is contraindicated, unsuccessful, or not im-

mediately available.

The main advantage of the Combitube for the emergency physician isthat it may obviate the need for cricothyrotomy in patients with failed

airways and those with maxillofacial or neck trauma [52]. The insertion

technique is easily learned, allowing medical personnel without training in

laryngoscopy to establish airway support in emergency situations. Studies of

untrained providers indicate that use of the Combitube is safe, effective, and

easily learned [5355]. The ETC has been used successfully in the prehospital

Fig. 8. The Combitube in the tracheal position. Reproduced with permission from Combitube

and Combitube SA (Small Adult) dual-lumen airways; Kendall, a unit of Tyco Healthcare

Group, LP, Mansfield, MA.



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environment and was preferred in one study over the LMA by emergency

medical personnel [56]. Oxygenation and ventilation using the Combitube

are comparable to, if not better than, those achieved with standard ETI, andthe Combitube may be used for prolonged ventilation [12,57].

It has been suggested that the ETC may offer an advantage over ETI in

patients with cervical spine injuries because it is inserted with the head and

neck in the neutral position, but this claim is not supported consistently by

the literature [58,59]. The Combitube offers adequate protection of the

airway from aspiration [60].


The Combitube is contraindicated in patients with intact laryngeal orpharyngeal reflexes, known esophageal pathology, or corrosive ingestions. It

is also contraindicated in patients with upper airway obstruction caused by

a foreign body or pathologic conditions. The Combitube SA, designed for

small adults, should not be used in patients under 4 feet tall. It is not

available in pediatric sizes. As with other blind techniques, the ETC presents

the potential for esophageal or pharyngeal trauma. There are case reports of

subcutaneous emphysema resulting from piriform sinus perforation or

esophageal laceration, apparently caused by direct esophageal trauma

during ETC insertion [6163]. Pneumomediastinum and pneumoperitoneumalso have been reported with its use [63]. Unlike an ETT, suction of tracheal

secretions is not possible with the Combitube.

The literature supports use of the ETC as an effective alternative to

endotracheal intubation. It is a noninvasive, easily acquired skill, and the

device functions when inserted into either the esophagus or the trachea.

Although its primary role is in prehospital care, emergency physicians

should be familiar with the device and consider it for difficult and failed

airway situations. Whenever conventional intubation cannot be performed

readily, the Combitube may be a useful alternative.

Lighted stylet

Light-guided intubation evolved from the observation that a bright light

transilluminates the soft tissues of the anterior neck when placed in the

trachea [64]. Using this principle, several lighted stylets or light wand de-

vices have been developed for blind oral or nasal endotracheal intubation.

Among the more popular is the Trachlight (Laerdal Medical, Armonk,

NY), a light wand device with three parts: (1) a reusable handle containinga battery pack and light source, (2) a flexible tube with a light bulb at the distal

tip, and (3) and a retractable stylet within the light wand to provide stability.

Insertion technique

The lighted stylet should be lubricated and positioned within a standard

ETT so the light bulb is just at the distal end of the tube. The tube is then



19/31

bent to a sharp 90 angle just proximal to the endotracheal cuff to facilitate

insertion around the tongue and maximize light intensity at the anterior

neck. The intubator can approach the patient from the head or the side. Thetongue and jaw are gently pulled forward from the side of the mouth with

the nondominant hand and the ETT is inserted blindly into the back of the

mouth at the midline. The tip of the ETT then is moved gently anteriorly

until a bright, well defined glow illuminates the thyroid prominence (Fig. 9).

The stylet then is retracted 510 cm to allow flexibility at the tip and the tube

is advanced until the light disappears just below the sternal notch. At this

point, the tip of the ETT is reliably positioned between the cords and the

carina. The stylet then is removed, followed by standard confirmation of

tube placement.


Most emergency physicians have limited experience with lighted stylets

and continue to use direct laryngoscopy as the primary method of securing

the airway. In difficult airway situations, however, the lighted stylet is an

appropriate backup choice. Indications for the lighted stylet include difficult

airways caused by anatomic considerations, temporomandibular immobil-

ity, large overbites, restricted mouth opening, or poor dentition [26,65]. It

has been used as a nasotracheal or orotracheal adjunct for severe facial

trauma [66,67].

Lighted stylet intubation requires training, but proficiency is acquired

quickly and emergency physicians have used these devices with success [68].

Studies comparing lighted stylet intubation with direct laryngoscopy have

shown faster times to intubation, fewer intubation attempts, less trauma,

and fewer adverse hemodynamic effects with the stylet [6871]. Also, in

patients with limited neck mobility or cervical spine injury, the lighted stylet

is able to negotiate oropharyngeal angles better than laryngoscopy, with

little or no head or neck manipulation [72]. In difficult airways, the lightwand can be used as intended or as a standard stylet to aid in direct

visualization of the cords.


There are no absolute contraindications to lighted stylets, but limitations

may be encountered in patients with known inflammatory laryngeal

disorders such as epiglottitis, retropharyngeal abscess, and tracheal stenosis.

They are relatively contraindicated in patients known to have laryngealtumors, polyps, foreign bodies, or an unknown cause of upper airway

compromise [73].

Factors such as copious oropharyngeal blood, dark skin, obesity, or

bright ambient lighting may limit the degree of transillumination achieved

with the lighted stylet. Conversely, in thin, fair-skinned patients, trans-

illumination may be present with esophageal placement [68]. It should be



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stressed that lighted stylet intubation is a blind technique and tracheal

placement should be confirmed by standard means. Trauma to the upper

airway using the lighted stylet is generally minor (bleeding, dysphagia, sore

throat) and less common than with direct laryngoscopy.

For the emergency physician, lighted stylet intubation can be a valuable

tool in difficult airway situations. It is an easily learned technique that is

Fig. 9. Light-guided intubation with Trachlight is based on the principle of transillumination

of the soft tissues in the neck. This technique takes advantage of the anterior location of the

trachea relative to the esophagus. A well defined, circumscribed glow can be seen in the anterior

neck when the endotracheal tube and light enter the glottic opening. If the tip of the tube is

placed in the esophagus, the light glow is diffuse and is not seen easily. Trachlight illustration

courtesy of Laerdal Medical Corporation.



21/31

quick and reliable and has minimal complications. In the ED, it is best used

as a backup technique for the patient who cannot be intubated by

traditional laryngoscopy but who can be ventilated. For patients withunstable cervical spine injuries or patients who cannot be intubated orally, it

may be a faster, more accessible first choice over fiberoptic intubation. As

with any airway device, preparation and frequent practice are essential to

maintain skills.

Gum elastic bougie

The gum elastic bougie or Eschmann stylet is an endotracheal tube

introducer originally described by Macintosh in 1949 as an aid to intubation[74]. The standard bougie is a semirigid malleable device, 60 cm long, made

of woven polyester with a resin coating. It has a diameter of 15 Fr (5 mm),

allowing easier passage through the vocal cords, and has a 40 angle 3.5 cm

from its distal tip to facilitate tracheal placement [75]. A plastic, less

expensive version of the bougie is available in the United States as the Flex-

Guide endotracheal tube introducer (ETTI) (GreenField Medical Sourcing,

Inc., Northborough, MA) [76]. The bougie is commonly used in Europe for

difficult intubations and has reduced the incidence of failed intubation and

cricothyrotomy [7678].

Insertion technique

When visualization of the vocal cords is poor or impossible, the

lubricated bougie is passed posterior to the epiglottis with the distal tip

angled anteriorly. If it enters the trachea, palpable clicks are felt as the tip of

the stylet passes over the tracheal cartilage rings. This washboard effect

and the fact the stylet cannot be passed beyond 40 cm (as the tip reaches the

small bronchi) are reliable signs of tracheal placement [79]. With esophageal

placement, clicks are not felt and the device can be advanced unobstructedbeyond 45 cm. With the bougie stabilized in place by an assistant and the

laryngoscope maintaining anterior displacement of the oropharyngeal

structures, an ETT is passed over the bougie into the trachea (Fig. 10).

Passage of the ETT is made easier by rotating the tube 90 counterclock-

wise, keeping the bevel of the tube posterior [80].


The bougie is indicated whenever anatomic, traumatic, or pathologic

factors prevent a good view of the vocal cords by direct laryngoscopy. It hasproven particularly useful in patients with airway edema, neck trauma, and

cervical spine immobilization [8183]. It is reasonable to attempt one

bougie-assisted intubation before performing a cricothyrotomy in certain

failed airway situations. It should be stressed that the bougie is no substitute

for proper technique and should be used only after other attempts to

optimize the laryngoscopic view have failed.



22/31

The bougie is an inexpensive, nonsurgical device that can be readilyavailable for urgent use in the ED. Unlike other airway adjuncts, it requires

little training time and no technical expertise beyond the skill of lar-

yngoscopy. Its flexibility allows the airway manager to customize the

bougieto suit the patients anatomy and increase the likelihood of success.

When inserted properly, the bougie is reliable in avoiding esophageal

intubations.


The bougie is contraindicated when the epiglottis cannot be visualizedunder any circumstances. Unlike some airway adjuncts, it is not a blindly

inserted device and should be guided under the epiglottis or through the

vocal cords under direct vision. It is not indicated for patients who require

nasotracheal intubation. The smallest ETT the standard bougie can

accommodate is a 6.0 mm ETT, limiting use to adults. Minor complications

associated with the bougie are uncommon and include local trauma to the

Fig. 10. Gum elastic bougie directed into the trachea. The endotracheal tube is inserted over the

bougie.FromMcCarroll SM, Lamont BJ, Buckland MR, Yates APB. The gum elastic bougie:

old but still useful [letter]. Anesthesiology 1988;68:6434; with permission.



23/31

airway, sore throat, and hoarseness [84]. Major complications such as

pharyngeal perforation, pneumothorax, hemopneumothorax, and medias-

tinal emphysema have been reported only rarely [85,86].The bougie is an inexpensive, easily used device and should be the first

backup device considered for the anticipated or known difficult airway.

Routine or difficult, a bougie should be kept within arms reach during every

intubation.

Digital intubation

Blind digital intubation or tactile intubation is an uncommon technique

in which the intubator guides the ETT into the trachea with his or her

fingers. The emergency physician has other devices and skills for manage-

ment of the difficult airway, but digital intubation deserves mention as a

valuable technique for some rarely encountered situations.

Technique

Using a stylet, the clinician forms an ETT into a U-shape. The intubator

approaches with the nondominant hand closest to the patient and an

assistant retracts the tongue. This pulls the epiglottis upward and facilitates

palpation of the epiglottis and glottic opening. The index and middle fingersof the nondominant hand are inserted palm down toward the base of the

tongue. The middle finger is used to identify the epiglottis and direct it

anteriorly. The ETT with stylet is then passed between the index and middle

fingers and advanced into the glottic opening, guided by the middle finger.

The stylet is then withdrawn and placement is confirmed.


Digital intubation is indicated when poor lighting, patient positioning,

copious airway secretions, or equipment failure render direct laryngoscopydifficult or impossible [87]. These situations are more likely to occur in the

prehospital setting than in the emergency department. Other indications

include cervical spine immobilization and disrupted airway anatomy. It

should be considered a last resort before cricothyrotomy for the failed

airway [88]. It can be performed as an adjunct to blind nasotracheal

intubation [89]. Other than an ETT and a stylet (and gloves), digital

intubation requires no technical equipment and can be performed rapidly in

poorly lit environments with the patient in any position, making it

particularly suitable to the prehospital setting. It has been used successfullyin pediatric patients and is preferred by some for neonatal resuscitation [90].


In the awake or semiconscious patient with intact oropharyngeal reflexes,

digital intubation is relatively contraindicated. Attempting this technique on

responsive patients can lead to oropharyngeal trauma and biting injuries.



24/31

Placing a bite block to prevent the patient from biting down reflexively and

double gloving may help minimize the risk for infectious disease trans-

mission. Other relative contraindications include caustic ingestion, thermalburns, and upper airway foreign bodies.

The length of the intubators fingers relative to the dimensions of the

patients oropharynx is an important predictor of success. Factors such as

limited mouth opening, large teeth, and distorted anatomy can further place

the intubator at a disadvantage. Iatrogenic trauma to the upper airway is

possible but can be avoided with gentle technique. Esophageal intubation is

a concern with digital intubation; therefore, diligent confirmation of

tracheal placement is required.

Although rarely used, difficult to perform, and risky, digital intubationcan be a life-saving skill and can prevent the need for creation of a surgical

airway. It should be considered for select patients with difficult airways

when alternative techniques are unavailable or inoperative. As with any

airway technique, digital intubation requires preparation and practice.

Retrograde intubation

Retrograde intubation (RI) is an invasive technique that involves

puncture through the cricothyroid membrane and passage of a guide wireretrograde into the oropharynx to facilitate ETT placement. Originally

described in 1960, RI is simplistic in principle but requires time and practice

to perform [91].

Technique

Commercially available kits for RI contain a syringe, an 18-gauge

introducer needle with catheter, a guide wire with a soft J-tip, and an

introducer catheter. Although RI is used most commonly for patients with

limited neck mobility, ideally the patients neck should be hyperextended.The cricothyroid membrane is identified and, time permitting, local an-

esthesia is infiltrated after skin preparation. While the larynx is stabilized, an

18-gauge needle attached to a syringe partially filled with saline is used to

puncture through the cricothyroid membrane in a cephalad direction.

Aspiration of air confirms placement in the trachea. The guide wire is then

threaded through the needle cephalad into the oropharynx and is retrieved

under direct visualization using Magill forceps. The guide wire then can be

placed directly into the lumen of an ETT or through the Murphy eye of the

ETT. Passing the wire through the Murphy eye permits slightly moreadvancement of the ETT below the vocal cords [92]. Alternatively, a guide

catheter can be placed over the guide wire to prevent lateral movement of

the ETT and ease its passage through the vocal cords [93]. With the ETT

advanced through the vocal cords and abutting the cricothyroid membrane,

the guide wire is pulled out through the proximal end of the ETT and the

ETT is advanced into its proper position. A common variation of this



25/31

technique involves threading a fiberoptic bronchoscope over the guide wire,

allowing direct visualization of the patients anatomy and the ability to

deliver continuous oxygen [94].


RI is indicated for the difficult airway resulting from cervical spine

immobilization, anatomic abnormality, or trauma, particularly upper

airway trauma that makes oral or nasal access difficult or impossible. It

should be considered when intubation has failed but adequate oxygenation

and ventilation can be maintained and when cricothyrotomy is impossible

or unavailable. RI has been used successfully in the prehospital setting and

the emergency department [95,96].


Relative contraindications to RI include unfavorable upper airway ana-

tomy such as flexion deformity of the neck, pretracheal mass or infection,

obesity, coagulopathy, and laryngeal injury [97]. Bleeding is a common

but generally minor problem with RI. Other potential complications

include subcutaneous emphysema, pneumomediastinum, infection, and

injuries to the trachea and laryngeal structures. Data on RI for the pediat-

ric population are limited, but the procedure seems to be useful and safe inexperienced hands, particularly with the adjunct use of a fiberoptic bron-

choscope [98].

Emergency physicians and anesthesiologists have used RI with success

for difficult airway management. It should be considered when cervical spine

immobilization, anatomic derangements, copious secretions, or blood

prevents adequate laryngoscopy, and after failed intubation when time

and patient status allow. Drawbacks to RI are that it is invasive, it can be

time consuming, and the equipment may not be readily available.

Jet ventilation

Percutaneous transtracheal jet ventilation (TTJV) involves puncturing

the cricothyroid membrane with a large-bore catheter for temporary

ventilation in failed airway situations. It is a simple, quick, and effective

technique associated with fewer complications than surgical cricothyrot-

omy. Although rarely performed, emergency physicians should be familiar

with this lifesaving skill for desperate, cannot intubate, cannot ventilate

scenarios when surgical cricothyroidotomy is unavailable or unsuccessful. Itis considered the surgical airway of choice in children younger than 12 years

of age as a bridge to securing a definitive airway.

Technique

If permissible, the patients neck should be hyperextended while the

cricothyroid membrane is identified. With the larynx stabilized, a large-bore



26/31

(12- to 16-gauge) catheter-over-needle attached to a 20-mL syringe partially

filled with saline is directed caudally through the cricothyroid membrane.

Large-bore wire-coiled transtracheal catheters that are less likely to kink arepreferable to intravenous catheters. Tracheal puncture is marked by

aspiration of air bubbles. The needle is then withdrawn slightly and the

catheter is advanced over the needle and into the airway with the aid of a small

skin incision. The catheter should be advanced to the hub, and placement in

the trachea reconfirmed by aspiration of air. Once in place, great care should

be taken to stabilize the catheter and prevent subsequent air leak at the incision

site. The hub of the catheter is then connected to the jet ventilation system.

A variety of TTJV systems are available. The most commonly used is

composed of high-pressure tubing in line with a regulator, a pressure gauge,and a jet ventilation toggle switch. The jet ventilation system is connected to

a wall oxygen source of 50 pounds per square inch (psi). In children older

than 5 years of age, the oxygen pressure should be down-regulated to 2030

psi to prevent barotrauma, and in children younger than 5 years of age, a bag

should be used for ventilation. Ordinarily, less than 1 second of inspiration

is required to provide an adequate tidal volume to the lung, whereas

exhalation occurs passively because of the elastic recoil of the lung in 23

seconds. An inspiration to expiration ratio (I:E) of 1:3 therefore is

recommended to allow adequate time for exhalation and avoid barotrauma.Maintaining upper airway patency by using a jaw thrust maneuver with

oropharyngeal and nasopharyngeal airways helps maximize exhalation,

preventing air trapping and high expiratory pressures.


In the emergency department, TTJV is rarely used. It is indicated for

cannot intubate, cannot ventilate situations when a surgical airway is not

possible and when the equipment or personnel for conventional airway

management are unavailable. It is generally considered to be quicker andless prone to complications than surgical cricothyrotomy; however, fa-

miliarity with the jet ventilator assembly is critical for rapid execution of this

technique [99]. It can be performed in all age groups and is the preferred

surgical airway in children.


Airway obstruction below the vocal cords and complete upper airway

obstruction render exhalation difficult or impossible and constitute relative

contraindications to TTJV. In these situations, surgical cricothyrotomy isthe best choice. Complications with TTJV are uncommon but include

subcutaneous emphysema, esophageal puncture, bleeding, exhalation dif-

ficulty, and barotrauma [100103]. The catheter used in TTJV can become

kinked or obstructed and does not confer airway protection.

TTJV should be viewed as a temporary rescue technique, primarily for

children under 12 years of age, until a definitive airway can be established.



27/31

Despite the infrequent need for TTJV in the ED, emergency physicians

should be well versed in this technique for crisis situations.

Summary

Rapid-sequence intubation using conventional laryngoscopic technique

remains the standard of airway management in emergency medicine and

continues to have a success rate of approximately 98%. Preparation and

proper intubation technique must be optimized at the initial attempt using

direct laryngoscopy. Failure causes multiple repeated attempts, leading to

a failed airway. Each repeated attempt increases the likelihood of bleeding,

oral, pharyngeal, and laryngeal edema, and malposition, causing decreasedvisualization of the glottic opening, equipment failure, and hypoxia.

Preparation must be an ongoing process. Faulty suction, no oxygen source,

choice of the wrong laryngoscopic blade or ETT, poor light source, or

misplaced equipment can domino into mechanical failure. Intubation equip-

ment stations must be inventoried constantly, organized, and kept simple

in their layout to decrease confusion during selection. Medication for seda-

tion and paralysis should be readily available and not kept distant from the

intubation station in a medication-dispensing unit that would require time

for acquisition.Proper positioning of the patient remains paramount for alignment of the

oral, pharyngeal, and laryngeal axis to provide optimal visualization of the

vocal cords. Proper technique during insertion of the laryngoscope blade in

the oral cavity for displacement of the tongue must be ensured. Without

proper technique, even with proper positioning, the glottic opening cannot

be visualized. Laryngeal pressure to maneuver the larynx into position

should be exerted initially by the laryngoscopists right hand and, when in

view, maintained by an assistant to free the laryngoscopists hand for ETT

insertion. With preparation and proper technique, the first attempt is thebest attempt, and the vicious cycle of multiple attempts and complications

will be averted.

Acknowledgment

The authors thank Linda J. Kesselring, MS, ELS, Division of Emergency

Medicine, University of Maryland School of Medicine, for help with

manuscript preparation.

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