NBCRNA EXAM QUESTIONS AND ANSWERS
What muscle abducts the vocal cords? - Answers- posterior cricoarytenoid
What is the only muscle that tenses (elongates) the vocal cords? - Answers-
cricothyroid "cords tense"
What muscle opens the glottis? - Answers- thyroepiglottic
What two muscles close the glottis? - Answers- aryepiglottic
oblique arytenoid
Recurrent laryngeal innervates... - Answers- below vocal cords --> the trachea
Branches off vagus in thorax
Motor: all intrinsic except cricothyroid
Glossopharyngeal innervates... - Answers- the vallecula
topside of epiglottis
soft palate
oropharynx
post 1/3 of tongue
tonsils
*afferent limb of gag reflex*
CN IX - sensory
Superior laryngeal innervates... - Answers- posterior epiglottis --> vocal cords
Internal branch is sensory - underside of epiglottis
External branch is motor - cricothyroid muscle
Trigeminal (V) V3 innervates... - Answers- anterior 2/3 tongue
Trigeminal nerve (V) contains what 3 branches? - Answers- V1 ophthalmic (anterior
ethmoidal) - nares/ant 1/3 septum
V2 maxillary (sphenopalatine) - turbinates/septum
V3 Mandibular (lingual)
Superior laryngeal nerve block: - Answers- 3ml at the inferior aspect of the greater
cornu of hyoid bone bilaterally
- helps tolerate FO intubation once past the oropharynx
Glossopharyngeal block: - Answers- 1-2 ml at the tonsillar pillar bilaterally
Transtracheal block: - Answers- 3-5 ml through the cricothyroid membrane
,What is most likely to injure the left RLN while sparing the right RLN? - Answers- Mitral
stenosis (LA enlargement compresses the nerve and may present as hoarseness)
PDA ligation
Aortic arch aneurysm
Thoracic tumor
Causes of left OR right RLN injury: - Answers- parathyroid or thyroid surgery
external pressure from LMA/ETT
neck tumor
neck extension
What muscles adduct the vocal cords and arytenoids?
- there are two - Answers- lateral cricoarytenoid
transverse arytenoid
What muscle shortens the vocal cords? (relaxes?)
- there are two - Answers- thyroarytenoid "they relax"
vocalis
The cricothyroid muscle is innervated by? - Answers- external branch of SLN
- the only branch that tenses (elongates) the VCs
The internal branch of the SLN is purely?
- sensory or motor? - Answers- sensory
Where does the right RLN loop?
left RLN loop? - Answers- under the right subclavian artery
- left under the aorta (more susceptible to injury)
For the patient in sitting position, order the cartilages from superior to inferior:
cricoid
epiglottis
arytenoid
corniculate - Answers- epiglottis
corniculate
arytenoid
cricoid
How many unpaired cartilages present in the larynx?
Paired? - Answers- 3 unpaired
3 paired
9 cartilages total
Where is the adult larynx located?
Infant larynx? - Answers- C3-C6
Infant is C2-C4
,What is the narrowest part of the airway? adult/infant - Answers- Vocal cords for adult
Cricoid for infant, if paralyzed = vocal cords
Risk factors for intraoperative laryngospasm? - Answers- GERD
Exposure to 2nd hand smoke
recent URI
Age < 1 year
HYPOcapnia
light anesthesia
saliva or blood in the upper airway
What is the definition of laryngospasm? - Answers- Sustained and involuntary
contraction of the vocal cord Adductors that result in the inability to ventilate.
Tensor palatine opens? - Answers- nasopharynx
Genioglossus opens? - Answers- the oropharynx
Hyoid muscles open? - Answers- the hypopharynx
Landmarks for the Larson's maneuver? - Answers- posterior: mastoid process
superior: skull base
Anterior: ramus of mandible
Muller's maneuver? - Answers- inhaling against a closed glottis
Which type of pneumocystis produce surfactant? - Answers- type 2
Three types of pneumocytes? - Answers- type 1 - 3
type 1 - cover 80% of alveolar surface
type 3 - macrophages that fight lung infection
Most common etiology of hypoxemia in the PACU? - Answers- V/Q mismatch:
specifically atelectasis
Result as FRC becomes smaller and there is less radial traction to hold the airways
open: - Answers- result is atelectasis, R -> L shunt, and hypoxemia
Intrapleural pressure becomes positive during: - Answers- The ONLY time intrapleural
pressure becomes positive is during forced exhalation, and pneumothorax
What is transpulmonary pressure? - Answers- alveolar pressure - intrapleural pressure
- always positive, keeps airway open
- Intrapleural always negative - keeps lungs inflated
, What muscles provide the most significant contribution to forced exhalation? - Answers-
rectus abdominus
Contraction of the inspiratory muscles reduces thoracic pressure and increases thoracic
volume, what law is this? - Answers- boyles law
What muscles contract during inspiration? - Answers- diaphragm and external
intercostals (tidal breathing)
accessory muscles: sternocleidomastoid and scalenes
Muscles of exhalation? - Answers- active exhalation: abdominal muscles
internal intercostals serve as secondary role in active
Alveolar compliance = - Answers- alveolar volume / alveolar pressure
The best ventilated alveoli are the? - Answers- most compliant!
- exchange more gas, volumes change more.
these alveoli reside at the steep slope of the curve
The least ventilated alveoli are the? - Answers- least compliant!
- exchange less gas, volumes change very little
reside near the top of the curve
Dead space is... - Answers- ventilation without perfusion
Shunt is... - Answers- perfusion without ventilation
Perfusion is what L/min?
Ventilation? - Answers- perfusion = 5L/min (greatest at lung base - gravity)
ventilation = 4L/min (greatest at base - higher compliance)
Compared to spontaneous ventilation, what happens to the Vd/Vt ratio when a patient is
placed on a ventilator? - Answers- The ratio increases.
What does the Vd/Vt ratio mean? - Answers- fraction of the tidal volume lost to dead
space
- gas not involved in alveolar gas exchange
Calculations for Vd/Vt ratio? - Answers- Vd = 2ml/kg
Vt = 6ml/kg
ex: 150/450 = 0.33%
Mechanical ventilation increases what west zone? - Answers- 1
- increases alveolar pressure and this increases ventilation relative to perfusion.
Increases to 0.5 or 50%
What muscle abducts the vocal cords? - Answers- posterior cricoarytenoid
What is the only muscle that tenses (elongates) the vocal cords? - Answers-
cricothyroid "cords tense"
What muscle opens the glottis? - Answers- thyroepiglottic
What two muscles close the glottis? - Answers- aryepiglottic
oblique arytenoid
Recurrent laryngeal innervates... - Answers- below vocal cords --> the trachea
Branches off vagus in thorax
Motor: all intrinsic except cricothyroid
Glossopharyngeal innervates... - Answers- the vallecula
topside of epiglottis
soft palate
oropharynx
post 1/3 of tongue
tonsils
*afferent limb of gag reflex*
CN IX - sensory
Superior laryngeal innervates... - Answers- posterior epiglottis --> vocal cords
Internal branch is sensory - underside of epiglottis
External branch is motor - cricothyroid muscle
Trigeminal (V) V3 innervates... - Answers- anterior 2/3 tongue
Trigeminal nerve (V) contains what 3 branches? - Answers- V1 ophthalmic (anterior
ethmoidal) - nares/ant 1/3 septum
V2 maxillary (sphenopalatine) - turbinates/septum
V3 Mandibular (lingual)
Superior laryngeal nerve block: - Answers- 3ml at the inferior aspect of the greater
cornu of hyoid bone bilaterally
- helps tolerate FO intubation once past the oropharynx
Glossopharyngeal block: - Answers- 1-2 ml at the tonsillar pillar bilaterally
Transtracheal block: - Answers- 3-5 ml through the cricothyroid membrane
,What is most likely to injure the left RLN while sparing the right RLN? - Answers- Mitral
stenosis (LA enlargement compresses the nerve and may present as hoarseness)
PDA ligation
Aortic arch aneurysm
Thoracic tumor
Causes of left OR right RLN injury: - Answers- parathyroid or thyroid surgery
external pressure from LMA/ETT
neck tumor
neck extension
What muscles adduct the vocal cords and arytenoids?
- there are two - Answers- lateral cricoarytenoid
transverse arytenoid
What muscle shortens the vocal cords? (relaxes?)
- there are two - Answers- thyroarytenoid "they relax"
vocalis
The cricothyroid muscle is innervated by? - Answers- external branch of SLN
- the only branch that tenses (elongates) the VCs
The internal branch of the SLN is purely?
- sensory or motor? - Answers- sensory
Where does the right RLN loop?
left RLN loop? - Answers- under the right subclavian artery
- left under the aorta (more susceptible to injury)
For the patient in sitting position, order the cartilages from superior to inferior:
cricoid
epiglottis
arytenoid
corniculate - Answers- epiglottis
corniculate
arytenoid
cricoid
How many unpaired cartilages present in the larynx?
Paired? - Answers- 3 unpaired
3 paired
9 cartilages total
Where is the adult larynx located?
Infant larynx? - Answers- C3-C6
Infant is C2-C4
,What is the narrowest part of the airway? adult/infant - Answers- Vocal cords for adult
Cricoid for infant, if paralyzed = vocal cords
Risk factors for intraoperative laryngospasm? - Answers- GERD
Exposure to 2nd hand smoke
recent URI
Age < 1 year
HYPOcapnia
light anesthesia
saliva or blood in the upper airway
What is the definition of laryngospasm? - Answers- Sustained and involuntary
contraction of the vocal cord Adductors that result in the inability to ventilate.
Tensor palatine opens? - Answers- nasopharynx
Genioglossus opens? - Answers- the oropharynx
Hyoid muscles open? - Answers- the hypopharynx
Landmarks for the Larson's maneuver? - Answers- posterior: mastoid process
superior: skull base
Anterior: ramus of mandible
Muller's maneuver? - Answers- inhaling against a closed glottis
Which type of pneumocystis produce surfactant? - Answers- type 2
Three types of pneumocytes? - Answers- type 1 - 3
type 1 - cover 80% of alveolar surface
type 3 - macrophages that fight lung infection
Most common etiology of hypoxemia in the PACU? - Answers- V/Q mismatch:
specifically atelectasis
Result as FRC becomes smaller and there is less radial traction to hold the airways
open: - Answers- result is atelectasis, R -> L shunt, and hypoxemia
Intrapleural pressure becomes positive during: - Answers- The ONLY time intrapleural
pressure becomes positive is during forced exhalation, and pneumothorax
What is transpulmonary pressure? - Answers- alveolar pressure - intrapleural pressure
- always positive, keeps airway open
- Intrapleural always negative - keeps lungs inflated
, What muscles provide the most significant contribution to forced exhalation? - Answers-
rectus abdominus
Contraction of the inspiratory muscles reduces thoracic pressure and increases thoracic
volume, what law is this? - Answers- boyles law
What muscles contract during inspiration? - Answers- diaphragm and external
intercostals (tidal breathing)
accessory muscles: sternocleidomastoid and scalenes
Muscles of exhalation? - Answers- active exhalation: abdominal muscles
internal intercostals serve as secondary role in active
Alveolar compliance = - Answers- alveolar volume / alveolar pressure
The best ventilated alveoli are the? - Answers- most compliant!
- exchange more gas, volumes change more.
these alveoli reside at the steep slope of the curve
The least ventilated alveoli are the? - Answers- least compliant!
- exchange less gas, volumes change very little
reside near the top of the curve
Dead space is... - Answers- ventilation without perfusion
Shunt is... - Answers- perfusion without ventilation
Perfusion is what L/min?
Ventilation? - Answers- perfusion = 5L/min (greatest at lung base - gravity)
ventilation = 4L/min (greatest at base - higher compliance)
Compared to spontaneous ventilation, what happens to the Vd/Vt ratio when a patient is
placed on a ventilator? - Answers- The ratio increases.
What does the Vd/Vt ratio mean? - Answers- fraction of the tidal volume lost to dead
space
- gas not involved in alveolar gas exchange
Calculations for Vd/Vt ratio? - Answers- Vd = 2ml/kg
Vt = 6ml/kg
ex: 150/450 = 0.33%
Mechanical ventilation increases what west zone? - Answers- 1
- increases alveolar pressure and this increases ventilation relative to perfusion.
Increases to 0.5 or 50%
