Exam 1 Airway

Question 1

What cranial nerve innervates the posterior one-third of the tongue and carries the sensation of taste?

Answer 1

The glossopharyngeal nerve (cranial nerve IX) provides sensory innervation of the posterior one-third of the tongue and carries taste sensations.

Question 2

What cranial nerve innervates the anterior two-thirds of the tongue and carries the sensation of taste?

Answer 2

The facial nerve (cranial nerve VII) provides sensory innervation of the anterior two-thirds of the tongue and carries taste sensations.

Question 3

Which region of the respiratory tract serves as the principal “physiologic heat and moisture exchanger” (hme)?

Answer 3

Upper respiratory tract (especially the nose)

Question 4

What is the primary function of the larynx? What are two other functions?

Answer 4

Primary: protect lungs from aspiration
Also: functions in respiration and in phonation

Question 5

What muscle acts as a barrier to regurgitation in the conscious subject?

Answer 5

In the awake subject, the cricopharyngeus muscle is the primary muscular barrier to regurgitation.

Question 6

Identify the muscles that abduct and adduct the vocal cords.

Answer 6

The posterior cricoarytenoids abduct (open) the cords; the lateral cricoarytenoids adduct (close) the cords.

Question 7

What intrinsic laryngeal muscle dilates the cords?

Answer 7

Posterior cricoarytenoids

Question 8

Which muscle tenses the vocal cords? Will the voice go up or down in pitch when the cords are tensed?

Answer 8

The cricothyroid muscle lengthens (tightens or tenses) the vocal cords. The voice will go up in pitch when the cords are tensed.

Question 9

What muscle relaxes the vocal cords?

Answer 9

thyroarytenoid relaxes the cords

Question 10

What nerve

provides sensation below the cords? What nerve provides sensation above the cords?

Answer 10

RLN: sensation below cords

internal branch of SLN: above cords

Question 11

What nerve provides sensation to the anterior and posterior surfaces of the epiglottis?

Answer 11

The internal branch of the superior laryngeal nerve supplies sensory fibers to the anterior and posterior surfaces of the epiglottis.

Question 12

Laryngospasm is caused by stimulation of which nerve?

Answer 12

stimulation of the superior laryngeal nerves

Question 13

What muscles are involved in laryngospasm? What motor (efferent) nerve is involved?

Answer 13

The cricothyroids are the muscles involved in laryngospasm. The cricothyroids adduct and tense the true vocal cords. Laryngospasm is mediated by the external branch of the superior laryngeal nerve. The external branch of superior laryngeal nerve provides motor innervation to the cricothyroid muscle.

Question 14

Injury to what nerve will prevent the vocal cords from coming together? What intrinsic laryngeal muscles are involved?

Answer 14

When the recurrent laryngeal nerve is damaged, the paralyzed vocal cord assumes a position intermediate between the abducted and adducted states. The paralyzed cord cannot adduct. The lateral cricoarytenoid causes adduction of the cords.

Question 15

When is a nasopharyngeal airway preferable to an oropharyngeal airway?

Answer 15

A nasopharyngeal airway (nasal airway, nasal trumpet) is better tolerated than an oral airway if the patient has intact airway reflexes. A nasal airway is preferable if the patient’s teeth are loose or in poor condition, if there is trauma or pathology of the oral cavity and can be used when the mouth cannot be opened.

Question 16

List four (4) contraindications to using a nasopharyngeal airway.

Answer 16

Contraindications to a nasopharyngeal airway include (1) anticoagulation, (2)basilar skull fracture, (3)pathology, sepsis, or deformity of the nasal cavity or nasopharynx, and (4) a history of nosebleeds requiring medical treatment.

Question 17

How do you estimate the correct length fora nasopharyngeal airway?

Answer 17

The length of a nasal airway can be estimated as the distance from the nares to the meatus (opening) of the ear. The length should be 2-4 cm longer than a corresponding oral airway.

Question 18

What is the purpose of an oral airway? List five (5)uses for an oral airway.

Answer 18

Any airway creates an artificial, patent passage to the hypopharynx. Oral airways are used to (1) prevent the patient from biting an oral tracheal tube, (2) protect the patient from biting the tongue, (3) facilitate oropharyngeal suctioning, (4) obtain a better mask fit, and (5) provide a pathway for inserting devices into the esophagus orpharynx.

Question 19

When is an oral airway indicated? C/I?

Answer 19

An oral airway is indicated for an obstructed upper airway in an unconscious patient and when there is need for a bite block in an unconscious patient. An oral airway is contraindicated in the awake or lightly anesthetized patient—the patient may cough or develop laryngospasm during air way insertion if laryngeal reflexes are intact.

Question 20

What is the purpose of the laryngoscope flange?

Answer 20

The flange projects off the left side of the laryngoscope and serves to sweep the tongue out of the way an to guide instrumentations along the laryngoscope blade.

Question 21

What is a lighted intubation stylet and when is it useful?

Answer 21

Alighted intubation stylet (lightwand, {flexible} lighted stylet, Trachhght”, illuminating or lighted intubating or intubation stylet) uses transillumination of the soft tissues in the anterior neck to guide the tip of the tracheal tube into the trachea or to determine the position of the tracheal tube or other airway device. During direct laryngoscopy, the lighted stylet can be used to improve the view in the hypopharynx. The lighted stylet is especially useful in situations where a fiberscope is unavailable or endoscopy is difficult to perform (e.g., when an airway is obscured by blood or secretions or when a patients head cannot be flexed or extended).

Question 22

Inspiratory pressure should be limited to what value when providing positive-pressure ventilation by a manual resuscitator (bag-valve mask, for example)?

Answer 22

When providing positive-pressure ventilation with a manual resuscitator, such as a bag-valve mask, it is imperative to limit the positive pressure
to 25 cm H2O to avoid inflating the stomach, which increases the risk of regurgitation.

Question 23

An end-tidal CO2 (ETCO2) partial pressure of < 5 mm-Hg is diagnostic of what?

Answer 23

Esophageal Intubation

Question 24

How can temporomandibular joint mobility be evaluated? What is the usual cause of temporomandibular joint immobility?

Answer 24

Temporomandibular joint mobility isbest evaluated by having the patient open his/her mouth as wide as possible. Arthritis is the usual cause of temporomandibular joint immobility.

Question 25

How wide should the adult be able to open his/her mouth?

Answer 25

The adult should be able to open his/her mouth so that there is a 40mm distance (two large finger breadths) between upper and lower incisors.

Question 26

Temporomandibular joint mobility may be assessed by measuring how far the mouth can be opened. What does this evaluate?

Answer 26

The motion of the condylar heads.

Question 27

Measuring the distance . from the anterior mandible to the thyroid cartilage tells you what?

Answer 27

This measurement, which is normally 6.5 cm or more in adults, helps preoperatively to assess the probable ease of tracheal intubation. If this distance is less than 6cm, it will be impossible to visualize the larynx.

Question 28

Why is the distance from the lower border of the mandible to the thyroid cartilage assessed with finger breadth preoperatively?

Answer 28

The laryngoscope displaces the tongue into this space. If this dimension is two finger breadths or less, visualization of the glottis may be compromised. If the distance from the lower border of the mandible to the thyroid notch with the neck fully extended is less than3-4 finger breadths, one may have difficulty visualizing the glottis.

Question 29

During airway evaluation, only the soft palate is seen during the"mouth fully opened, tongue protruded, no phonation" maneuver. What is the Mallampati classification of this patient?

Answer 29

Class III

Question 30

The preoperative evaluation of the patient reveals no organic, physiologic, biochemical, or psychiatric disturbances. What ASA classification is this patient?

Answer 30

ASA: Class I Healthy Patient

Question 31

Describe the ASA Class II status and list seven pathophysiologic examples.

Answer 31

The ASA Class II patient has mild to moderate systemic disturbance that may not be related to the reason for surgery. Seven examples of pathophysiologic disturbances consistent with ASA Class II are: (1) heart disease that slightly limits physical activity; (2) essential hyper-tension; (3) diabetes mellitus; (4) chronic bronchitis; (5) anemia; (6) morbid obesity; and, (7) extremes of age.

Question 32

Explain why peak inspiratory pressure (pip) may increase during the case.

Answer 32

Increases in peak inspiratory pressure (pip) may indicate increased airway resistance owing to:(1)endotracheal tube obstruction,(2)accumulation of secretions, blood or edema fluid in the airway, (3) an increase in bronchial smooth muscle tone (bronchospasm), or (4) endobronchial intubation.

Question 33

What are signs and symptoms of intraoperative bronchospasm?

Answer 33

Intraoperative bronchospasm is usually manifested as wheezing, increasing peak inflation pressures (pip) secondary to decreased pulmonary compliance, decreasing exhaled tidal volumes, or a slowly rising waveform on the capnograph.

Question 34

If the endotracheal tube slips into the mainstem bronchus, what changes will be observed?

Answer 34

With unintentional endobronchial intubation, oxygen saturation (SOJ W.II decrease and peak inspiratory pressure will increase. Unilateral breath sounds also signify endobronchial intubation.

Question 35

Which gas mixture would decrease the work of breathing of patients with partial respiratory obstructions?

Answer 35

Helium-oxygen (Heliox)

Question 36

State five (5) risk factor for difficult mask ventilation, from greatest risk to least.

Answer 36

greatest to least risk are: (1) presence of a beard, (2) body mass index >26 kg/m^ (3) lack of teeth (edentulous), (4) age > 55 years, and (5) history of snoring.

Question 37

What is the pressure limit for positive-pressure face mask ventilation?

Answer 37

Positive-pressure ventilation via a face mask should normally be limited to 20cm H^O to avoid stomach inflation.

Question 38

List three functions of the laryngeal mask airway (lma).

Answer 38

(1) an alternative to ventilation through a face mask (2) partial protection of the larynx from pharyngeal (but not laryngeal) secretions (3) hand-free ventilation (it is not necessary to use one hand constantly to support the face mask on the mandible)

Question 39

List four situations for which the laryngeal mask airway (lma) is appropriately used?

Answer 39

(1) as a substitute for the classic mask airway to eliminate the presence of a relatively large mask and practitioner's hand that may interfere with surgical access; (2) to establish an emergency airway in awkward settings for intubation such as the lateral or prone positions; (3) to establish an airway in the patient in whom either mask ventilation or tracheal intubation is difficult; (4) to provide a conduit to facilitate fiberoptic or blind oraltracheal intubation (for endotracheal tubes that are not larger than 6.0 mm internal diameter).

Question 40

Can the laryngeal mask airway (lma) be used in place of an endotracheal tube during administration of anesthesia?

Answer 40

No. The laryngeal mask airway (lma) is clearly nota replacement for the endotracheal tube. The lma provides an alternative to ventilation through a face mask or endotracheal tube.

Question 41

The laryngeal mask airway (lma) can be used with up to how many cm H2O pressure?

Answer 41

ventilatory pattern should be chosen which results in peak airway pressures < 20 cm H2O.

Question 42

The laryngeal mask airway is (lma) contraindicated in four conditions. Identify these four conditions.

Answer 42

(1) who are at risk for aspiration including gross or morbid obesity, pregnancy, multiple or massive injury, acute abdominal or thoracic injury, any abdominal condition associated with delayed gastric emptying, or use of opioid medication prior to fasting, or patients who have not fasted; (2) with fixed decreased pulmonary compliance, such as pulmonary fibrosis, because it forms a low pressure seal around the larynx; (3)With long-term mechanical ventilatory support; and, (4) with intact upper airway reflexes, as the reflexes may cause laryngospasm.

Question 43

Block of which nerve abolishes the gag reflex and decreases the hemodynamic response to laryngoscopy?

Answer 43

The glossopharyngeal (GPN) block is highly effective in abolishing the gag reflex and decreasing the hemodynamic response to laryngoscopy, including awake laryngoscopy.

Question 44

What is the Murphy eye on a tracheal tube?What is the purpose of the Murphy eye?

Answer 44

A Murphy eye is a hole through the tracheal tube wall opposite to the bevel. The purpose of the Murphy eye is to provide an alternate pathway for gas flow if the bevel becomes occluded.

Question 45

What is the name for tracheal tubes that lack a Murphy eye?

Answer 45

Magill type tubes

Question 46

What are three advantages of a Macintosh blade compared with a Miller blade?

Answer 46

Advantages of the Macintosh blade include (1)a smaller likelihood of dental trauma, (2) more room for passing the endotracheal tube, and (3) less bruising of the epiglottis.

Question 47

If an attempt at intubating the general surgery patient has failed but mask ventilation with 100% 02 is possible, what options should be considered?

Answer 47

Something must be changed to increase the likelihood of success such as: (1) reposition patient; (2) decrease tube size; (3) use a retrograde wire (sty let) to assist with the intubation; (4) change blade; (5) try nasal intubation; (6) ask for assistance from another anesthetist or anesthesiologist, or (7) use an lma.