Airway integrity, assurance of oxygenation, ventilation, and
prevention of aspiration are the mainstays of emergency airway management.
The indications for tracheal intubation in the ED include correction
of hypoxia or hypercarbia, prevention of impending hypoventilation,
and ensuring maintenance of a patent airway. Secondary indications
include provision of a route for resuscitative medication administration
and to permit temporizing paralysis during diagnostic testing.
Rapid-sequence intubation (RSI) is the simultaneous administration
of an induction agent and neuromuscular blocking agent to facilitate
endotracheal intubation. It is the method of choice for emergency
airway management.1 RSI is associated with the
highest intubation success rate in the majority of emergency airway
cases and is superior to sedation alone.
There are two circumstances in which RSI may not be the first
technique of choice. Patients in cardiac or respiratory arrest,
or near-arrest, in whom a response to laryngoscopy is unlikely and
time is very limited, may be intubated without pharmacologic assistance.
The second exception is patients with anticipated airway difficulties
in whom the risks of failed intubation, bag-mask ventilation, or
rescue are considered too high to remove the patient’s
airway protection and respirations with paralysis. Although RSI-facilitated
endotracheal intubation is the foundation of emergency airway management,
providers must anticipate airway difficulties and be facile with
alternative airway techniques, bag-mask ventilation, rescue airway
devices, and surgical airways.
Endotracheal intubation is the most reliable way to ensure a
patent airway, provide oxygenation and ventilation, and prevent
Clinical assessment alone of oxygenation and ventilation may
be unreliable in a chaotic ED. Pulse oximetry and capnography help
guide decisions regarding tracheal intubation.
Equipment needed at the bedside before beginning intubation is
listed in Table 30-1.
Table 30-1 Equipment Needed
for Airway Management
| Save Table
Table 30-1 Equipment Needed
for Airway Management
|Oxygen source and tubing|
|Clear face masks—various sizes and shapes|
|Oropharyngeal airways—small, medium, large|
|Nasopharyngeal airways—small, medium, large|
|Endotracheal tubes—various sizes|
|Laryngoscope blades and handles|
|Water-soluble lubricant or anesthetic jelly|
|Alternative or rescue devices: laryngeal mask airway, intubating laryngeal
mask airway, Combitube® (Sheridan Catheter Corp.,
Argyle, NY), King LT® (King Systems, Noblesville,
|Surgical rescue equipment—surgical cricothyroidotomy
|Medications for topical airway anesthesia, sedation, or rapid-sequence intubation|
Rescue devices and a surgical airway option are ideally located
in a designated difficult airway cart in the ED. Similar equipment
available in pediatric sizing should also be present and is discussed
in detail in Chapter 29, Pediatric Airway Management.
When preparing for intubation, select the appropriate-size endotracheal tube (ETT)
and an additional tube (0.5 to 1.0 mm in diameter smaller), and
check the cuffs for air leaks with a 10-mL syringe. ETTs with high-volume,
low-pressure cuffs are preferred. The approximate sizes for ETTs
are 8.0- to 8.5-mm inner diameter for an adult male and 7.5- to
8.0-mm inner diameter for an adult female. The second hole at the
end of the tube above the bevel is called the Murphy eye. This
hole permits some uninterrupted airflow if the tip is occluded.
Test the light on the laryngoscope and then pick an appropriate-size blade.
Laryngoscopes can be fitted with either straight or curved blades. The
straight Miller blade is used to physically lift the epiglottis.
The curved Macintosh blade is placed in the vallecula above the
epiglottis and is used to indirectly lift the epiglottis off the
larynx when applying traction on the hypoepiglottic ligament (Figure 30-1). Expertise with both blade types
is desirable because they offer different advantages. The curved
blade may cause less trauma and is less likely to stimulate an airway
reflex, because, when used properly, it does not directly touch
the larynx. It also allows more room for adequate visualization
during tube placement and is helpful in the obese patient. The straight
blade is mechanically easier to insert in many patients who do not
have large central incisors. Selecting the proper-size blade greatly
facilitates intubation. In adults, the curved Macintosh #3
is the most popular, and #4 is more useful in large patients.
The straight Miller #2 or #3 is popular for the
A. Curved or Macintosh blade. B. Straight
or Miller blade.
There are a variety of other straight and curved blades available.
For example, the Guedel blade is a straight blade with an acute,
72-degree angle to the handle. The Schapira straight blade has a
side concavity that helps cradle the large tongue and push it toward
the left side of the mouth. The CLM curved laryngoscope blade has
a hinged tip, which permits elevation of the epiglottis with minimal
force, as the fulcrum is repositioned down within the pharynx.
Begin preoxygenation as soon as intubation becomes a consideration. Preoxygenate
all patients being intubated, including those with no apparent hypoxia.
Preoxygenation displaces nitrogen with oxygen in the alveolar space,
creating a potential reservoir of oxygen that may prevent hypoxia
for several minutes of apnea. Even with adequate preoxygenation,
hypoxia develops more quickly in children, pregnant women, obese
patients, and in hyperdynamic states. To preoxygenate, administer
100% oxygen for 3 minutes, using a non-rebreather mask
supplied with 15 L/min of oxygen. Nasal cannulas do not
provide optimal preoxygenation. Non-rebreather masks typically
deliver 65% to 75% oxygen. Circumstances may require
preoxygenation with an appropriate bag-mask ventilator, which can
deliver 90% to 97% oxygen. There are a number
of bag-mask devices, which vary significantly in their oxygen delivery.
The optimal bags ...