General Flashcards
1
Q
List the anatomic differences between paediatric and adult airways (8).
A
1) Proportionately smaller infant/child larynx 2) Narrowest portion: Cricoid cartilage in infant/child; vocal folds in adult 3) Relative vertical location: C3–C5 in infant/child; C4–C6 in adult 4) Epiglottis: Longer, narrower, and stiffer in infant/child 5) Aryepiglottic folds closer to midline in infant/child 6) Vocal folds: Anterior angle with respect to perpendicular axis of larynx in infant/child 7) Pliable laryngeal cartilage in infant/child 8) Mucosa more vulnerable to trauma in infant/child
2
Q
What are the main laryngeal muscle groups?
A
1) extrinsic - move the larynx as a whole 2) intrinsic - move the various cartilages in relation to each other
3
Q
What is the innervation of the larynx?
A
2 branches of each vagus nerve a) superior laryngeal b) recurrent laryngeal
4
Q
The ____________ nerve supply all of the intrinsic muscles of the larynx except for the ____________
A
recurrent laryngeal, cricothyroid
5
Q
List the characteristics of the cricothryoid membrane
A
1) joins the superior aspect of the cricoid cartilage and the inferior edge of the thyroid cartilage 2) 8-12mm in width, 10.4-13.7mm in height 3) 1-1.5 finger breadths below the laryngeal prominence/thyroid notch 4) central portion known as the conus elasticus and two lateral thinner portions 5) proximity to the vocal folds (which may be 0.9 cm above the ligaments’ upper border) *** any incisions should be made in the lower 1/3 and pointed posteriorly, to his the back side of the cricoid cartilage ring
6
Q
In the adult, the first tracheal ring is anterior to the ________ cervical vertebrae.
A
sixth
7
Q
The trachea ends at the carina, opposite the _______ thoracic vertebra)
A
fifth
8
Q
Cartilaginous rings support the first _____ generations of the bronchi.
A
seven
9
Q
What airway anomalies are associated with Pierre Robin syndrome
A
Micrognathia, macroglossia, glossoptosis, cleft soft palate
10
Q
What airway anomalies are associated with Treacher Collins syndrome
A
Auricular and ocular defects; malar and mandibular hypoplasia, microstomia, choanal atresia
11
Q
What airway anomalies are associated with Goldenhar syndrome
A
Auricular and ocular defects; malar and mandibular hypoplasia; occipitalization of atlas
12
Q
What airway anomalies are associated with Down syndrome
A
Poorly developed or absent bridge of the nose; macroglossia, microcephaly, cervical spine abnormalities
13
Q
What airway anomalies are associated with Klippel–Feil syndrome
A
Congenital fusion of a variable number of cervical vertebrae; restriction of neck movement
14
Q
What airway anomalies are associated with Alpert syndrome
A
Maxillary hypoplasia, prognathism, cleft soft palate, tracheobronchial cartilaginous anomalies
15
Q
What airway anomalies are associated with Beckwith syndrome
A
Macroglossia
16
Q
What airway anomalies are associated with Cretinism
A
Absent thyroid tissue or defective synthesis of thyroxine; macroglossia, goiter, compression of trachea, deviation of larynx/trachea
17
Q
What airway anomalies are associated with Cri du chat syndrome
A
Microcephaly, micrognathia, laryngomalacia, stridor
18
Q
What airway anomalies are associated with Meckel syndrome
A
Microcephaly, micrognathia, cleft epiglottis
19
Q
What airway anomalies are associated with von Recklinghausen disease
A
Increased incidence of pheochromocytoma; tumors may occur in the larynx and right ventricle outflow tract
20
Q
What airway anomalies are associated with Hurler/Hunter syndrome
A
Stiff joints, upper airway obstruction due to infiltration of lymphoid tissue; abnormal tracheobronchial cartilages
21
Q
What airway anomalies are associated with Pompe disease
A
Muscle deposits, macroglossia
22
Q
What airway anomalies are associated with Rheumatoid arthritis
A
Temporomandibular joint ankylosis, cricoarytenoid arthritis, deviation of larynx, restricted mobility of cervical spine
23
Q
What airway anomalies are associated with Ankylosing spondylitis
A
Ankylosis of cervical spine; less commonly ankylosis of temporomandibular joints; lack of mobility of cervical spine
24
Q
What airway anomalies are associated with Acromegaly
A
Macroglossia; prognathism
25
What are the sensitivity and specificity of the Mallampati score?
49, 86
26
What are the sensitivity and specificity of the thyromental distance?
20, 94
27
What are the sensitivity and specificity of the sternomental distance?
62, 82
28
What are the sensitivity and specificity of mouth opening?
46, 89
29
What are the 4 conditions in which tracheal intubation should be considered non-routine?
(1) The presence of equally important priorities to the management of the airway (such as a full stomach or open globe) (2) abnormal airway anatomy (3) an emergency (4) direct injury to the upper airway and lar- ynx and/or trachea.
30
What are the criteria for difficult BMV?
1) Inability for one anesthesiologist to maintain oxygen saturation \>92% 2) Significant gas leak around face mask 3) Need for ≥4 L/min gas flow (or use of fresh gas flow button more than twice) 4) No chest movement 5) Two-handed mask ventilation needed 6) Change of operator required
31
List the independent risk factors for difficult intubation in order of utility - odds ratio (5)
Presence of beard (3.18) BMI \> 26 (2.75) Lack of teeth (2.28) Age \> 55 (2.26) History of snoring (1.84)
32
List the uses of U/S in airway management
confirmation of tracheal intubation exclusion of esophageal intubation, lung excursion (and assuring bilateral ventilation), verifying ventilation in the absence of CO2 detection, and identifying the cricoid membrane.
33
List the uses of U/S in airway management
1) confirmation of tracheal intubation 2) exclusion of esophageal intubation 3) lung excursion (and assuring bilateral ventilation) 4) verifying ventilation in the absence of CO2 detection 5) identifying the cricoid membrane 6) structural abnormalities 7) estimating tube size
34
The nitrogen volume of the lung can be as much as _____ of the functional residual capacity
95%
35
List the time to desaturation
a) 6mins b) 2.7 mins c) 1-2 mins
36
Compared to prolonged TV breathing on room air, 4 VC breaths produce a high ______ , but \_\_\_\_\_\_\_\_\_
PaO2, shorter time to desaturation
37
What techniques help with maximum pre-oxygenation in the obese patient?
head up position, Bi-pap
38
What is the anatomic effect of the sniffing position?
anteriorizing the base of the tongue and the epiglottis
39
Name some conditions that increase the risk of epistaxis with nasal airway insertion?
1) coagulopathy (inherited, iatrogenic, pathological) 2) pregnancy 3) HHT 4) malignant HTN
40
How do you size a nasal airway?
from the nare to the thyroid notch
41
How do you size an oral airway?
teeth (or alveolar ridge) to the mandibular angle
42
SGAs are associated with lower incidence of \_\_\_\_\_\_\_, \_\_\_\_\_\_\_\_\_\_, ___________ on emergency as compared to tracheal intubation.
sore throat, coughing, laryngospasm
43
The disposable version of the LMA classic is:
The LMA unique
44
For LMAs, adequacy of the seal depends on __________ and \_\_\_\_\_\_\_\_, not \_\_\_\_\_\_\_\_\_\_\_\_
size and placement, not cuff filling
45
The LMA intracuff pressure should never exceed ________ (and should be periodically monitored if nitrous oxide is used)
60cm H20
46
[t/f] Classic LMAs have no effect on aspiration risk in elective cases
T
47
List the advantages of LMAs
1) Improved protection of the airway from blood and surgical debris 2) Reduced cardiovascular responses 3) Reduced coughing on emergence 4) Reduced laryngospasm after airway device removal 5) Improved oxygen saturation after airway device removal 6) Ability to administer oxygen until complete restoration of airway reflexes
48
Contraindications to SGA use
1) risk of gastric content aspiration (full stomach, hiatus hernia, GERD, obstruction, delayed gastric emptying) 2) poor lung compliance or high airway resistance 3) glottic or subglottic airway obstruction 4) mouth opening
49
How do rates of sore throat compare in ETT vs SGA
4-50% for SGA, 30-70% of ETT
50
What are the nerves at risk from pressure neuropraxia with SGA use?
hypoglossal, lingual, inferior alveolar
51
What are the drawbacks of the laryngeal tube?
a) less effective than LMA for kids under 10 b) not recommended for kids under 10kg c) more pressure on posterior hypophayrnx with ulceration risk
52
List the SGAs in use today
1) LMA classic (reusable)/unique (disposable) 2) LMA flexible - designed for ENT/ophtho surgery 3) Laryngeal tube/laryngeal tube suction - double cuff, aspiration protection 4) Cookgas Air-Q - intubating LMA (not as good as Fastrach) 5) Proseal (reusable)- double lumen LMA 6) Supreme - disposable Proseal with fixed Fastrach curvature 7) I gel - double lumen LMA in solid elastomer gel body, with gastric drain
53
List the features of the Proseal LMA
1) Gastric drain - Position confirmation, Suprasternal notch test, No gas leak via gastric drain, Successfully passing gastric tube, Active gastric emptying, Passive gastric emptying, Protection from gastric-content aspiration 2) Posterior cuff - Increased seal pressure 3) Bite block - Prevents patient biting, obstruction, Position confirmation, 50% or more of the bite block should be within the oral cavity 4) Wire reinforced airway barrel - Reduced overall size, Decreased ability to tracheal intubate 5) Large barrel/bite block - First insertion less successful than LMA classic, rotational stability, size down from LMA classic
54
What is the difference in positive pressure allowable with the proseal?
40mmH20 with proseal compared to 30mmH20 with others
55
What are the specifications of the true sniffing position?
Neck flexes 35 degrees, head extended 15 degrees
56
[t/f] Full atlanto-occipital extension limits mouth opening
False, increases mouth opening by 26%
57
Mallampati score is large an approximation of:
relative mass of tongue
58
Unan- ticipated failure of DL is primarily a problem of:
tongue displacement
59
\_\_\_\_\_\_\_\_\_\_\_\_\_\_ as the most commonly undiagnosed cause of unanticipated difficult DL.
lingual tonsil hyperplasia
60
What are the definitions of the Mallampati scores?
Class I: uvula, facial pillars, soft palate Class II: faucial pillars, soft palate Class III: soft and hard palate Class IV: hard palate only
61
What are the definitions of the Cormack and Lehane laryngeal view scoring system?
Grade 1: visualization of the entire glottic aperture Grade 2: includes visualization of only the posterior aspects of the glottic aperture Grade 2A: partial vocal cord view Grade 2B: only arytenoids and epiglottis Grade 3: is visualization of the tip of the epiglottis, and grade 4: is visualization of no more than the soft palate
62
A Cormack–Lehane grade 3 or 4 is expected in \_\_\_% to \_\_\_% of adult laryngoscopies.
1.5 - 8.5
63
What is the POGO score?
Percent of glottic opening (during direct laryngoscopy) 0-100% of the span form the anterior commissure to the interarytnoid notch
64
What are the average ETT depths for female and male?
21cm (F), 23cm (M)
65
What are the gold standard for intubation confirmation?
a) direct visualization b) sustained detection of exhaled CO2
66
What are the accessory methods of intubation confirmation? (7)
1) auscultation over the chest and abdomen 2) visualization of chest excursion 3) observation of condensation in the ETT 4) use of a self-inflating bulb 5) lighted stylet 6) fiberoptic devices 7) ultrasound or chest X-ray
67
[t/f] Claims for laryngeal injury during DL arise more often in “easy” as opposed to difficult laryngoscopies.
T
68
The 60-degree angulation of the GlideScope reduces cervical spine motion by ____ at the C2 to C5 segments compared with Macintosh laryngoscopy.
50%
69
[T/F] There is no significant advantage of the GlideScope in preventing hemodynamic responses to orotracheal intubation as compared with the Macintosh direct laryngoscope.
T (although studies vary)
70
What is the advantage of the airtraq over VL?
tracheal tube distal end can be visualized throughout its course reducing the opportunity for soft tissue trauma.
71
Who are the patients at risk for aspiration?
a) Full stomach (recent ingestion) b) Diabetes mellitus (with autonomic neuropathy) c) Gastroesophageal reflux/hiatal hernia d) Pregnancy e) Acute pain/acute opioid therapy f) renal colic g) Bowel obstruction/intra-abdominal process
72
Summarize the ASA Fasting guidelines
Water 2hrs Breast milk 4hrs Infant forumula 6h Nonhuman milk 6h Light meal 6 hrs Full or fatty meal 8hrs
73
What are the methods to reduce aspiration risk?
1) Minimize intake, adequate preoperative fasting, clear liquids only if necessary 2) Increase gastric emptying, prokinetics (e.g., metoclopramide) 3) Reduce gastric volume and acidity, Nasogastric tube, nonparticulate antacid (e.g., sodium citrate), H2-receptor antagonists (e.g., famotidine), proton pump inhibitors (e.g., lansoprazole) 4) Airway management and protection, cricoid pressure, cuffed endotracheal intubation
74
[T/F] The extent of delayed gastric emptying with diabetes mellitus correlates does not correlate with age, duration of disease, preprandial HbA1C, peripheral neuropathy or autonomic neuropathy.
F. The extent of delayed gastric emptying with diabetes mellitus correlates well with the presence of autonomic neuropathy, but not with age, duration of disease, preprandial HbA1C, or periph- eral neuropathy.
75
[T/F] Famotidine effectively reduces gastric volume and increases gastric pH better than ranitidine given a few hours before surgery.
T
76
How are PPIs most effectively administered?
Two successive doses, in the evening before and on the morning of anesthesia. Single dose rabeprazole and lansoprazole should be administered on the morning of anesthesia. Single-dose therapy with omeprazole is best given the previous night
77
How is sodium citrate most effectively administered?
1 hour pre-op
78
[T/F] In situ NG reduces the efficacy of cricoid pressure
F
79
Cricoid pressure entails the downward displacement of the __________ against \_\_\_\_\_\_\_\_\_\_.
cricoid cartilage, vertebral bodies
80
Contraindications to cricoid pressure?
1) active vomiting 2) cervical spine fracture 3) laryngeal fracture
81
Successful blind intubation via the LMA Fastrach occurred in \_\_\_\_% of patients
97%
82
If intubation is unsuccessful, Fastrachs should not be used for procedures longer than
15 mins
83
List the subjective criteria for routine awake extubation (6)
1) Follows commands 2) Clear oropharynx/hypopharynx (e.g., no active bleeding, secretions cleared) 3) Intact gag reflex 4) Sustained head lift for 5 s, sustained hand grasp 5) Adequate pain control 6) Minimal end expiratory concentration of inhaled anesthetics
84
List the objective criteria for routine awake extubation (7)
1) Vital capacity: ≥10 mL/kg 2) Peak voluntary negative inspiratory pressure: \>–20 cm H2O 3) Tidal volume \>6 cc/kg 4) Sustained tetanic contraction (5 s) 5) T1/T4 ratio \>0.7 6) Alveolar–arterial Pao2 gradient (on Fio2 of 1):
85
List the causes of ventilatory compromise during tracheal extubation (17)
Residual anesthetic Poor central respiratory effort Decreased respiratory rate Decreased respiratory drive in response to CO2 Decreased respiratory drive in response to O2 Reduced tone of upper airway musculature Reduced gag and swallow reflex Decreased threshold to laryngospasm Surgical airway compromise Surgical airway edema Vocal cord paralysis Arytenoid cartilage dislocation Supraglottic edema with airway obstruction by the epiglottis Retro arytenoid edema with limited vocal fold abduction Subglottic edema Tracheomalacia (from long-standing tracheal intubation) Bronchospasm
86
List the complications of tracheal extubation (13)
Respiratory drive failure Hypoxia (e.g., atelectasis) Upper airway obstruction (e.g., edema, residual anesthetic) Vocal fold–related obstruction (e.g., vocal cord paralysis) Tracheal obstruction (e.g., subglottic edema) Bronchospasm Aspiration Hypertension Increased intracranial pressure Increased pulmonary artery pressure Increased bronchial stump pressure (e.g., after pulmonary resection) Increased ocular pressure Increased abdominal wall pressure (wound dehiscence risk)
87
Laryngospasm at the time of extubation accounts for \_\_\_% of all critical postoperative respiratory events in adults.
23
88
What is the physiological process of laryngospasm?
contraction of the lateral cricoarytenoids, the thyroarytenoid, and the cricothyroid muscles
89
Sugammadex can be used for which NMBs?
Rocurimium or Vecuronium
90
How does recurrent laryngeal nerve paralysis compromise ventilation?
Unopposed adduction
91
In \_\_\_\_\_\_\_\_, the cuff-leak test was found to be especially unreliable.
trauma patients
92
[T/F] single-dose injection of dexamethasone given 1 hour before extubation does not reduce the number of patients requiring reintubation.
T. Multiple doses throughout surgery are required.
93
What morbidity is associated with airway exchange catheters?
loss of airway control, mucosal trauma, pneumothorax, esophageal intubation, and death. Complication rates of up to 60% have been reported.
94
What are the pre-requisites for AEC use?
1) the patient should meet extubation criteria 2) should have been breathing 100% oxygen 3) AEC with an external diameter closest to the internal diameter of the in situ ETT should be used (less chance of murphy's eye passage) 4) marks may be matched with the markings on the ETT 5) maintaining AEC position as the ETT is removed 6) if ventilation required, The patient should be flaccid or muscle relaxed to prevent glottic closure, an oral airway or other device should be used to maintain an open upper airway, and careful inspiratory pressure and dura- tion must be titrated to observed chest expansion and recoil.
95
Contraindications to regional anesthesia from an airway management perspective
Cavity-invading surgery Significant sedation needed Extensive neuroaxial/local anesthetic required or risk of intravascular injection/absorption is high Poor access to the airway Surgery cannot be stopped once started
96
Cautions for awake intubation?
cardiac ischemia/risk bronchospasm increased IOP increased ICP
97
Contraindications to awake intubation?
patient refusal inability to cooperate allergy to local anesthetics
98
What are the doses of dexmedatomidine used for sedation intubation?
A loading dose of dexmedetomidine is 1 μg/kg intravenously over 10 minutes, and maintenance infusion dose is 0.2 to 0.7 μg/kg/h
99
What is the max dose of topical 4% cocaine
200mg
100
How is cocaine metabolized?
pseudocholinesterase
101
Systemic absorption is (higher, lower) with nebulizer use
higher
102
Benzo- caine may produce \_\_\_\_\_\_\_\_\_\_\_, which is treated by the administration of \_\_\_\_\_\_\_\_\_\_\_\_\_.
methemoglobinemia, methylene blue (1 to 2 mg intravenously over several minutes).
103
Benzocaine may produce \_\_\_\_\_\_\_\_\_\_\_, which is treated by the administration of \_\_\_\_\_\_\_\_\_\_\_\_\_.
methemoglobinemia, methylene blue (1 to 2 mg intravenously over several minutes).
104
What is the innervation of the nasal cavity?
1) greater and lesser palatine nerves (innervating the nasal turbinates and most of the nasal septum) from the sphenopalatine ganglion 2) anterior ethmoid nerve (innervating the nares and anterior third of the nasal septum).
105
What is the innervation of the nasal cavity?
1) greater and lesser palatine nerves (innervating the nasal turbinates and most of the nasal septum) from the sphenopalatine ganglion 2) anterior ethmoid nerve (innervating the nares and anterior third of the nasal septum).
106
Describe the oral approach to nasal block
In the oral approach, a needle is introduced into the greater palatine foramen, which can be palpated in the posterior lateral aspect of the hard palate, 1 cm medial to the second and third maxillary molars. Anesthetic solution (1 to 2 mL) is injected with a spinal needle inserted in a superior/ posterior direction at a depth of 2 to 3 cm.
107
What is the innervation of the oropharynx?
The oropharynx is innervated by branches of the vagus, facial, and glossopharyngeal nerves.
108
Describe the course, branches and innervation of the glossopharyngeal nerve
The glossopharyngeal nerve travels anteriorly along the lateral surface of the pharynx a) lingual branch supplies the posterior third of the tongue, the vallecula, the anterior surface of the epiglottis b) pharyngeal branch: the walls of the pharynx c) tonsillar branch: tonsils (internal branch of the superior laryngeal nerve innervates base of tongue, epiglottis, aryepiglottic folds, and arytenoids)
109
Describe the glossopharyngeal nerve block
The branches of this nerve are most easily accessed as they transverse the palatoglossal folds. Operator displaces the extended tongue to the contralateral side and a 25-gauge spinal needle is inserted into the fold near the floor of the mouth.
110
Which branch of the glossopharyngeal nerve is most easily block with the transoral approach?
lingual
111
Which branches of the vagus innervates the larynx and what structures?
a) internal branch of the superior laryngeal nerve innervates base of tongue, epiglottis, aryepiglottic folds, and arytenoids b) recurrent laryngeal - vocal folds and trachea
112
the external branch of the superior laryngeal nerve supplies motor innervation to the \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
cricothyroid muscle.
113
Describe the external block of the internal branch of the superior laryngeal nerve
The clinician identifies the superior cornu of the hyoid bone beneath the angle of the mandible. Using one hand, medially directed pressure is applied to the contralat- eral hyoid cornu, displacing the ipsilateral hyoid cornu toward the clinician. Caution must be taken to locate the carotid artery and displace it if necessary. The needle can be inserted directly over the hyoid cornu and then “walked” off the cartilage in an anterior–caudad direction until it can be passed through the ligament to a depth of 1 to 2 cm. Local anesthetic (1.5 to 2 mL) is injected in the space between the thyrohyoid membrane and the pharyngeal mucosa.
114
How do you block the recurrent laryngeals?
transtracheal injection through the CTM
115
What drug can be used to minimize nasal bleeding?
oxymetazoline, xylometazoline (otrivin)
116
Relative contraindications to FOB (5)
Hypoxia Heavy airway secretions not relieved with suction or antisialagogues Bleeding from the upper or lower airway not relieved withsuction Local anesthetic allergy (for awake attempts) Inability to cooperate (for awake attempts)
117
List the common causes of FOB failure
1) Lack of experience: Not practicing on routine intubations 2) Failure to adequately dry the airway: Underdose or rushed technique 3) Failure to adequately anesthetize the airway of the awake patient: Secretions not dried; rushed technique 4) Nasal cavity bleeding: Inadequate vasoconstriction; rushed technique; forcible ETT insertion 5) Obstructing base of tongue or epiglottis: Poor choice of intubating airway; require chin lift/jaw thrust 6) Inadequate sedation of the awake patient 7) Hang-up: ETT too large 8) Fogging of the FOB: Suction or oxygen not attached to working channel; cold bronchoscope
118
Rate of can't LMA
1:800,000
119
Rate of can't intubate/ventilate
1:10,000
120
What is the major disadvantage of the LMA
lack of mechanical protection from regurg and aspiration
121
Contraindications to cricothryoidotomy
Children less than 6 Laryngeal fracture
122
What are the appropriate pressures and rate for jet ventilation?
A 50 psi source with a metered and adjustable hand-controlled valve and a Luer-lock connector is down-regulated to 15 to 30 psi of oxygen (central hospital supply or regulated cylinder) is delivered directly through the catheter, with insufflations of 1 to 1.5 seconds at a rate of 12 insufflations per minute. If a 14-gauge catheter has been placed, this system will deliver a tidal volume of 400 to 700 mL.
123
Draw the ASA difficult airway algorithm
