Airway Management in the Adult

Question 1

What is the preferred pathway for passage of nasal airway devices?

Answer 1

The inferior meatus, between the inferior turbinate and the floor of the nasal cavity, is the preferred pathway for passage of nasal airway devices

Question 2

Beneath the tongue, the … muscles separate the floor of the mouth into the sublingual space superiorly and the submental space inferiorly. Cellulitis (… angina) or hematoma formation in these spaces can cause elevation and posterior displacement of the tongue and resultant airway obstruction

Answer 2

mylohyoid

Ludwig’s

Question 3

The oropharynx begins at the … and extends inferiorly to the level of the …

Answer 3

soft palate

epiglottis

Question 4

The oropharynx lateral walls contain the …, also termed the …, respectively; these folds contain the palatine tonsils, which can hypertrophy and cause airway obstruction

Answer 4

palatoglossal folds and the palatopharyngeal folds

anterior and posterior faucial (tonsillar) pillars

Question 5

The base of the tongue lies in the anterior aspect of the oropharynx, connected to the epiglottis by the … folds, which bound paired spaces known as the …

Answer 5

glossoepiglottic

valleculae (although these are frequently referred to as a single space called the vallecula)

Question 6

The hypopharynx begins at the level of the epiglottis and terminates at the level of the cricoid cartilage, where it is continuous with the esophagus. The larynx protrudes into the hypopharynx, creating …

Answer 6

two piriform recesses on either side

Question 7

The cricoid cartilage, at the level of the … vertebra, is the inferior limit of the larynx and is anteriorly connected to the thyroid cartilage by the cricothyroid membrane

Answer 7

sixth cervical

Question 8

The … are the most superior structure within
the laryngeal cavity

Answer 8

ventricular folds (also referred to as the vestibular folds
or false vocal cords)

Question 9

The space between the vocal cords is termed…

Answer 9

the glottis

Question 10

The portion of the laryngeal cavity above the glottis is known as the …, and the portion inferior to the vocal cords is known as the …

Answer 10

vestibule

subglottis

Question 11

The trachea begins at the level of the cricoid cartilage and extends to the carina at the level of the … vertebra; this length is … in the adult

Answer 11

fifth thoracic

10 to 15 cm

Question 12

A Mallampati zero classification has been proposed when …

Answer 12

the epiglottis can be visualized during examination of the oropharynx

Question 13

During DL, the tongue is displaced into the submandibular space; glottic visualization may be inadequate if this space is diminished because of a small mandible. This scenario is frequently referred to as an …

Answer 13

anterior larynx

Question 14

What find in the physical examitaion may indicate a reduced mandibular space?

Answer 14

A thyromental distance of less than 6.5 cm (3 fingerbreadths), as measured from the thyroid notch to the lower border of the mentum, is indicative of reduced mandibular space and may predict difficulty with intubation

Question 15

Describe the Simplified Airway Risk Index

Answer 15

Mouth opening
< 4 cm: 1 point
≥ 4 cm: 0 points

Thyromental distance
< 6.0 cm: 2 points
6.0 - 6.5: 1 point
> 6.5 cm: 0 points

Mallampati
I: 0 points
II: 0 points
III: 1 point
IV: 2 points

Neck movement
< 80°: 2 points
80 - 90°: 1 point
> 90°: 0 points

Ability to prognath
Yes: 0 points
No: 1 point

Weight
< 90kg: 0 points
90 -110kg: 1 point
> 110kg: 2 points

History of difficult intubation
Definite: 2 points
Questionable: 1 point
None: 0 points

A score of ≥ 4 indicates difficult direct laryngoscopy

Question 16

The routine use of drugs as prophylaxis against aspiration pneumonitis is not recommended by the ASA guidelines but may be beneficial in patients with specific risk factors for aspiration, such as a …

The goal of aspiration prophylaxis is twofold: …

Commonly used agents include …
These drugs may be used alone or in combination

Answer 16

full stomach, symptomatic gastroesophageal reflux disease (GERD), hiatal hernia, presence of a nasogastric tube, morbid obesity, diabetic gastroparesis, or pregnancy

to decrease gastric volume and to increase gastric fluid pH

nonparticulate antacids (e.g., Bicitra), promotility drugs (e.g., metoclopramide), and H2-receptor antagonists.

Question 17

One of the most important teleologic functions of the larynx is that of airway protection, which is primarily provided by the…

This reflex is triggered by sensory receptors in the … and results in strong …

Answer 17

glottic closure reflex

glottic and subglottic mucosa

adduction of the vocal cords

Question 18

An exaggerated, maladaptive manifestation of the glottic closure reflex is called laryngospasm

Laryngospasm is usually provoked by … stimulation attributable to …

Answer 18

glossopharyngeal or vagal

airway instrumentation or vocal cord irritation (e.g., from blood or vomitus) in the setting of a light plane of anesthesia (stage II of the Guedel classification), but it can also be precipitated by other noxious stimuli and can persist well after the removal of the stimulus

Question 19

Explain the Larson Maneuver

Answer 19

Bilateral pressure at the laryngospasm notch between the condyle of the mandible and the mastoid process.

It can be effective at treating laryngospasm by causing an intense, painful stimulus, which may function to terminate laryngospasm by arousing a semiconscious patient or by activating autonomic pathways

Question 20

In combination with propofol …/kg, remifentanil …/kg can reliably provide good-toexcellent intubating conditions. When combined with cricoid pressure and an avoidance of mask ventilation, this induction technique can be used for rapid sequence induction

Answer 20

2 mg

4 to 5 μg

Question 21

In awake tracheal intubation, topical application of local anesthetic should primarily be focused on the …

Answer 21

base of the tongue (pressure receptors here act as the afferent component of the gag reflex), the oropharynx, the hypopharynx, and the laryngeal structures

Question 22

Before topical application of local anesthetic to the airway, administration of … should be considered to …

Answer 22

an anticholinergic agent

aid in the drying of secretions, which helps improve both the effectiveness of the topical local anesthetic and visualization during laryngoscopy

Question 23

In an awake intubation, topical application of local anesthetic to the airway mucosa is often sufficient.

If supplemental anesthesia is required, then a variety of nerve blocks may be used. Three of the most useful are the …

Answer 23

glossopharyngeal nerve block, superior laryngeal nerve block, and translaryngeal block

Question 24

The glossopharyngeal nerve supplies sensory innervation to …, and is the afferent pathway of the…

Answer 24

the posterior third of the tongue, vallecula, the anterior surface of the epiglottis, and the posterior and lateral walls of the pharynx

gag reflex

Question 25

How to perform a glossopharyngeal nerve block?

Answer 25

To block this nerve, the tongue is displaced medially, forming a gutter (glossogingival groove). A 25-gauge spinal needle is inserted at the base of the anterior tonsillar pillar, just lateral to the base of the tongue, to a depth of 0.5 cm. After negative aspiration for blood or air, 2 mL of 2% lidocaine is injected. The process is then repeated on the contralateral side.
The same procedure can be performed noninvasively with cotton-tipped swabs soaked in 4% lidocaine; the swabs are held in place for 5 minutes

Question 26

The superior laryngeal nerve, a branch of the vagus nerve, provides sensory input from …

Answer 26

the lower pharynx and the upper part of the larynx, including the glottic surface of the epiglottis and the aryepiglottic folds

Question 27

Blockade of superior laryngeal nerve may be achieved …

Answer 27

using one of three landmarks:
- Using either the superior cornu of the hyoid or the superior cornu of the thyroid cartilage, a 25-gauge spinal needle is walked off the cornu anteriorly toward the thyrohyoid ligament. Resistance is felt as the needle is advanced through the ligament, usually at a depth of 1 to 2 cm. After negative aspiration for blood and air, 1.5 to 2 mL of 2% lidocaine is injected and then repeated on the opposite side.

The third landmark for the superior laryngeal nerve block is particularly useful in patients who are obese, in whom
palpation of the hyoid or the superior cornu of the thyroid cartilage may be difficult or uncomfortable for the patient.
In this approach, the needle is inserted 2 cm lateral to the superior notch of the thyroid cartilage and directed in a posterior and cephalad direction to 1 to 1.5 cm depth, where 2 mL of 2% lidocaine is infiltrated and, again, repeated on
the contralateral side

Question 28

Translaryngeal (or transtracheal) block provides anesthesia of the …

This block may be particularly useful in situations where …; it makes the presence of the ETT in the trachea more comfortable.

The CTM is identified, and a 20- to 22-gauge needle attached to 5-mL syringe is directly advanced posteriorly and slightly caudally until
air is aspirated, at which point … mL of either 2% or 4% lidocaine is quickly injected. This causes the patient to cough anesthetizing the vocal cords and the trachea. To minimize the risk of trauma, a catheter may first be placed over the needle and the local anesthetic then injected through the catheter

Answer 28

trachea and vocal cords

a neurologic examination is needed after intubation

4

Question 29

The maximum dose of lidocaine for application to the airway is not well established; different sources suggest total doses in the range of …

Answer 29

4 to 9 mg/kg

Question 30

Predictors of Difficult Mask Ventilation

Answer 30

□ Obstructive sleep apnea or history of snoring
□ Age older than 55 years
□ Male gender
□ Body mass index of 30 kg/m2 or greater
□ Mallampati classification III or IV
□ Presence of a beard
□ Edentulousness

Question 31

The LMA ProSeal (PLMA, LMA North America, San Diego, CA) is a reusable second-generation SGA that incorporates a posterior cuff, improving the perilaryngeal seal and allowing for PPV at pressures up to 30 cm H2O. It also incorporates a …

Answer 31

gastric drainage tube that allows for gastric access with an orogastric tube and channels any regurgitated gastric contents away from the airway, effectively isolating the respiratory and gastrointestinal tracts

Question 32

The LMA Gastro is a single-use silicone LMA designed for …

Answer 32

upper gastrointestinal endoscopy procedures, simultaneously protecting the airway and facilitating passage of an endoscope

Question 33

Predictors of Difficult Laryngoscopy

Answer 33

□ Long upper incisors
□ Prominent overbite
□ Inability to protrude mandible
□ Small mouth opening
□ Mallampati classification III or IV
□ High, arched palate
□ Short thyromental distance
□ Short, thick neck
□ Limited cervical mobility

Question 34

Surgical cricothyrotomy materials and technique

Answer 34

Equipment
□ No. 10 scalpel
□ Bougie with a coudé (angled) tip
□ Cuffed endotracheal tube (ETT) with a 6-mm internal diameter

Technique
1. Stand on the patient’s left-hand side if you are right handed
(reverse if left handed).

2. Stabilize the larynx using the left hand.
3. Use the left index finger to identify the cricothyroid membrane (CTM). If the CTM is not palpable, make a 8-10 cm vertical incision in the midline and use blunt dissection with the fingers of both hands to separate tissues and identify and stabilize the larynx with the left hand.
4. Holding the scalpel in your right hand, make a transverse stab
   incision through the skin and cricothyroid membrane with the cutting edge of the blade facing toward you.
5. Keep the scalpel perpendicular to the skin and turn it through
   90° so that the sharp edge points caudally (toward the feet).
6. Swap hands; hold the scalpel with your left hand.
7. Maintain gentle traction, pulling the scalpel toward you (laterally) with the left hand, keeping the scalpel handle vertical to the skin (not slanted).
8. Pick the bougie up with your right hand.
9. Holding the bougie at a right angle to the trachea, slide the coudé tip of the bougie down the side of the scalpel blade furthest from you into the trachea.
10. Rotate and align the bougie with the patient’s trachea and
    advance gently up to 10-15 cm.
11. Remove the scalpel.
12. Stabilize trachea and tension skin with left hand.
13. Railroad a lubricated size 6.0 mm cuffed tracheal tube over
    the bougie.
14. Rotate the tube over the bougie as it is advanced. Avoid
    excessive advancement and endobronchial intubation.
15. Remove the bougie.
16. Inflate the cuff and confirm ventilation with capnography.

Question 35

Complications associated with extubation

Answer 35

□ Laryngospasm and bronchospasm
□ Upper airway obstruction
□ Hypoventilation
□ Hemodynamic changes (hypertension, tachycardia)
□ Coughing and straining, leading to surgical wound dehiscence
□ Laryngeal or airway edema
□ Negative-pressure pulmonary edema
□ Paradoxical vocal cord motion
□ Arytenoid dislocation
□ Aspiration

Question 36

Factors associated with increased extubation risk

Answer 36

Airway Risk Factors
□ Known difficult airway
□ Airway deterioration (bleeding, edema, trauma)
□ Restricted airway access
□ Obesity and obstructive sleep apnea
□ Aspiration risk

General Risk Factors
□ Cardiovascular disease
□ Respiratory disease
□ Neuromuscular disease
□ Metabolic derangements
□ Special surgical requirements