Airway Devices

Question 1

What FiO2 range would expect a nasal cannula to

deliver?

Answer 1

The FiO2 delivered by a nasal cannula can vary significantly, but
the ranges you can predict that would be delivered by varying flow
rates are: 1 L/min: 0.21-0.24, 2L/min: 0.23-0.28, 3L/min: 0.27-
0.34, 4L/min: 0.31-0.38, 5 or 6 L/min: 0.32-0.44.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 1282.

Question 2

What are the two main factors that determine the

resistance to gas flow in an anesthesia circuit?

Answer 2

Resistance to gas flow is a function of the length of the tube and
its diameter. The shorter the length and the larger the diameter,
the less resistance it offers.
Dorsch JA, Dorsch SE. A Practical Approach to Anesthesia
Equipment. Philadelphia, PA: Lippincott Williams and Wilkins,
2011: 111.

Question 3

What is meant by zero, low, medium, and highcapacity

oxygen delivery devices?

Answer 3

The capacity of an oxygen delivery device refers to the size of the
built-in oxygen reservoir. A nasal cannula is a zero-capacity
device as it has no oxygen reservoir. A tracheostomy mask or
pediatric face mask is considered a low capacity device. A simple
face mask and an aerosol face tent are both considered medium
capacity devices. A nonrebreather mask is a high capacity device.
Sandberg W, Urman RD, and Ehrenfield JM. The MGH Textbook
of Anesthetic Equipment. Philadelphia, PA: Elsevier; 2011: 73-74.

Question 4

Why should cuff pressure be monitored in patients
undergoing long-term ventilation via an endotracheal
tube?

Answer 4

Cuff pressure that is too high can cause ischemia of the tracheal
wall. Low cuff pressure in the endotracheal tube increases the
risk that material can pass beside the cuff and into the lungs and
is associated with an increased risk of pneumonia in patients on
long-term ventilation.
Dorsch JA, Dorsch SE. A Practical Approach to Anesthesia
Equipment. Philadelphia, PA: Lippincott Williams and Wilkins,
2011: 352-353.

Question 5

What are the concerns one may have when using an

LMA?

Answer 5

An LMA doesn’t protect against gastric secretions. Ventilation
requiring pressures in excess of 20 cm H2O may result in inflation
of the stomach. It can become malpositioned, resulting in an
inability to ventilate. It is contraindicated in pharyngeal pathology
such as tumor or abscess. Pathology at or below the level of the
LMA may make it an ineffective means of ventilation.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 451.

Question 6

How do you choose the appropriate size LMA?

Answer 6

The LMA comes in several sizes: 1 for infants, 2 for children 6.5-
20 Kg, 2.5 for children 20-30 Kg, 3 for children and small adults
greater than 30 Kg, and size 4-5 for larger adults.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 319.

Question 7

Does an LMA protect the airway from pharyngeal

secretions?

Answer 7

Yes. It does not, however, protect the airway from gastric
secretions. Aspiration is a possibility in patients who experience
reflux during the anesthetic.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 317

Question 8

Will an LMA protect against laryngospasm?

Answer 8

No. The LMA is a supraglottic airway. Because it does not stent
the cords open as an endotracheal tube would, it is unable to
prevent laryngospasm. Additionally, a laryngeal mask airway
normally produces a gas leak when air pressures reach 20 cm
H2O and would be ineffective in producing the amount of positive
pressure required to break a laryngospasm.
Longnecker DE, Newman MF, Brown DL, Zapol WM.
Anesthesiology. 2nd ed. New York: McGraw-Hill; 2012: 556.

Question 9

What are the advantages and disadvantages of a lowvolume,

high-pressure cuff on an endotracheal tube?

Answer 9

A low-volume, high pressure cuff offers increased visibility during
intubation because the cuff lies flat against the tube when not
inflated. It also offers greater protection against aspiration.
Because it requires a high intracuff pressure to overcome the
decreased compliance of the cuff wall, it is difficult to assess how
much pressure is being applied to the tracheal wall. Because this
results in an increased risk for tracheal ischemia it is not suitable
for long-term intubations.
Dorsch JA, Dorsch SE. Understanding Anesthesia Equipment.
5th ed. Philadelphia, PA: Lippincott Williams and Wilkins, 2008:
575.

Question 10

What is the indication for using an anode (armored)

endotracheal tube?

Answer 10

The anode (or armored) tube contains an embedded wire that is
designed to prevent kinking when the tube is bent.
Longnecker DE, Newman MF, Brown DL, Zapol WM.
Anesthesiology. 2nd ed. New York: McGraw-Hill; 2012: 560.

Question 11

What is the indication for using an oral or nasal RAE

endotracheal tube?

Answer 11

Nasal and oral RAE tubes possess pre-formed bends that direct
the tube away from the surgical field and are especially useful in
oral and facial surgeries.
Longnecker DE, Newman MF, Brown DL, Zapol WM.
Anesthesiology. 2nd ed. New York: McGraw-Hill; 2012: 560.

Question 12

What is the indication for using a double-lumen

endotracheal tube?

Answer 12

Double-lumen tubes and bronchial blocker tubes possess the
ability to direct gas flow to one or another lung during surgery.
Longnecker DE, Newman MF, Brown DL, Zapol WM.
Anesthesiology. 2nd ed. New York: McGraw-Hill; 2012: 560.

Question 13

How should the endotracheal tube be positioned when

performing a nasal intubation?

Answer 13

When performing a nasotracheal intubation, the tracheal tube
should be inserted into the nares at an angle perpendicular to the
face with the bevel directed away from the turbinates.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 330.

Question 14

What internal diameter endotracheal tube would be

appropriate for a full-term infant?

Answer 14

For a full-term infant, a 3.5 mm internal diameter tube is
recommended. For older children, the formula: 4 + (Age/4) is a
useful predictor for the appropriate endotracheal tube size.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 321.

Question 15

What is the most reliable method of confirming

placement of the endotracheal tube in the trachea?

Answer 15

Although several factors such as chest rise, oxygen saturation,
direct visualization, and breath sounds should be assessed,
persistent end-tidal carbon dioxide detection is the most reliable
indicator that the endotracheal tube is positioned in the trachea.
Dorsch JA, Dorsch SE. A Practical Approach to Anesthesia
Equipment. Philadelphia, PA: Lippincott Williams and Wilkins,
2011: 371.

Question 16

What is the primary advantage of the video-assisted

laryngoscope (ex. Glidescope)?

Answer 16

It can provide equal or better visualization of the airway without
manipulation of the head into the sniffing position.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 457

Question 17

What are the advantages and disadvantages of the

Bullard laryngoscope?

Answer 17

The Bullard laryngoscope is quicker to use than a flexible,
fiberoptic scope. It is useful in patients with limited neck or
oropharyngeal mobility. It results in less dental trauma and has a
lower risk of failed intubation than traditional laryngoscopy and is
more resistant to problems with secretions. It does not
accommodate double-lumen or metallic laser tubes well and using
an andotracheal tube larger than 7.5 mm can result in posterior
displacement of the introducing stylet.
Dorsch JA, Dorsch SE. A Practical Approach to Anesthesia
Equipment. Philadelphia, PA: Lippincott Williams and Wilkins,
2011: 323.

Question 18

What are some of the limitations of the traditional
flexible fiberoptic laryngoscope? How can they be
overcome?

Answer 18

The lens of the scope can become fogged, making visualization
difficult. This is more common if the scope is cold, so soaking it
in warm saline prior to the procedure helps prevent fogging. The
fiberoptic strands in the scope are fragile and can become broken
easily. As strands break, visualization can become limited. Care
must be taken to protect the instrument from damage and it
should be stored in a safe, secure location. Secretions and blood
can obstruct the view of the scope. It contains a suction channel
that runs the length of the scope that can be irrigated with normal
saline to wash secretions out of the viewing area.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 454-455.

Question 19

What are the advantages of the use of a lighted stylet

over traditional laryngoscopy?

Answer 19

Although the success rate in using a lighted stylet such as the
Trachlite is similar to that of traditional laryngoscopy, it is less
affected by an anterior airway, is less stimulating than
laryngoscopy, and results in a lower incidence of sore throat.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 453.

Question 20

What are the components on all self-inflating manual

resuscitators? What components are optional?

Answer 20

All self-inflating manual resuscitators have a self-expanding bag, a
bag inlet valve, and a nonrebreathing valve. Optional components
include CO2 detectors, airway pressure monitor, PEEP valve,
pressure-limiting devices, and scavenging devices.
Dorsch JA, Dorsch SE. A Practical Approach to Anesthesia
Equipment. Philadelphia, PA: Lippincott Williams and Wilkins,
2011: 183.

Question 21

What are the factors that determine the patient’s
minute volume when being ventilated by a self-inflating
manual resuscitator?

Answer 21

The tidal volume, respiratory rate, and operator skill level are the
determinants of the patient’s minute volume when being ventilated
by a self-inflating manual resuscitator. The operator must be able
to maintain an open airway and adequate seal when using the
device to deliver adequate minute ventilation.
Dorsch JA, Dorsch SE. A Practical Approach to Anesthesia
Equipment. Philadelphia, PA: Lippincott Williams and Wilkins,
2011: 188.

Question 22

According to ASTM standards, what is the minimum
FiO2 a self-inflating manual resuscitator should be
able to deliver when connected to an oxygen source?

Answer 22

40%
Dorsch JA, Dorsch SE. A Practical Approach to Anesthesia
Equipment. Philadelphia, PA: Lippincott Williams and Wilkins,
2011: 188-189.

Question 23

With what airway device is the risk of high airway
pressure the greatest when ventilating with a selfinflating
manual resuscitator?

Answer 23

High airway pressure is a hazard when using a self-inflating
manual resuscitator if a pressure relief valve is not utilized. The
risk is greater with endotracheal tubes than with mask or
supraglottic devices such as the LMA or laryngeal tube which tend
to leak at a lower pressure than an endotracheal tube.
Dorsch JA, Dorsch SE. A Practical Approach to Anesthesia
Equipment. Philadelphia, PA: Lippincott Williams and Wilkins,
2011: 189

Question 24

Which cuff should be inflated after insertion of a

Combitube?

Answer 24

After inserting a Combitube, you should inflate both the proximal
and distal cuffs. The Combitube will be placed within the
esophagus in 95% of insertions in which case ventilation through
the blue tube will force air through the side perforations and into
the larynx. If the Combitube enters the trachea, ventilation can
proceed by connecting the circuit to the shorter, clear tube.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 320.

Question 25

Which endotracheal tube stylet allows the stylet angle

to be adjusted during laryngoscopy?

Answer 25

The Schroeder stylet is a plastic, disposable stylet that allows the
stylet angle to be adjusted while performing the laryngoscopy.
Miller RD, Pardo MC. Basics of Anesthesia. 6th ed. Philadelphia,
PA: Elsevier Saunders; 2011: 231.

Question 26

What serves as confirmation of correct placement of

an Eschmann stylet?

Answer 26

Confirmation of appropriate placement of an Eschmann stylet
(gum elastic bougie) is made when you feel the stylet travel across
the bumpy surface of the tracheal rings, but this sensation may
not always be noticed. Although the stylet may strike a surface
and stop, this can occur in both the esophagus and the trachea
and is not confirmation.
Nagelhout JJ, Zaglaniczny KL. Nurse Anesthesia. 4th ed.
Philadelphia, PA: WB Saunders Company; 2010: 454.