Airway Flashcards
T/F
breathing can be performed exclusively by the diaphragm
True
in normal lungs this is possible
In the adult, the tip of an orotracheal tube moves an average of __ cm with flexion/extension of the neck, but can travel as much as ___ cm. In infants and children, displacement of even __ cm can move the tube above the vocal cords or below the carina
In the adult, the tip of an orotracheal tube moves an average of 3.8 cm with flexion/extension of the neck, but can travel as much as 6.4 cm. In infants and children, displacement of even 1 cm can move the tube above the vocal cords or below the carina
When ____ is reduced, larger changes in pleural pressure are needed to create the same tidal volume (Vt).
lung compliance
Patients with low lung compliance breathe with (smaller/larger) Vt and more rapidly, making spontaneous ____ the most sensitive clinical index of lung compliance.
smaller Vt
respiratory rate
Carotid and aortic bodies are stimulated by ____ values less than ____.
Thus, patients who depend on hypoxic ventilatory drive must have PaO2 values below ____.
PaO2
60 to 65 mmHg
65 mmHg
The three etiologies of hyperventilation
arterial hypoxemia
metabolic acidemia
central etiologies (e.g., intracranial hypertension, hepatic cirrhosis, anxiety, pharmacologic agents).
Increases in dead space ventilation primarily affect ____ elimination (with minimal influence on arterial oxygenation)
Increases in physiologic shunt primarily affect ____ (with minimal influence on CO2 elimination).
Increased dead space ventilation affects CO2 elimination
Increased shunt affects arterial oxygenation
*dead space: volume of ventilated air that does not participate in gas exchange; fills the conducting zone of respiration made up by the nose, trachea, and bronchi
alveolar ventilation : dead space ventilation ratio
What is it during spontaneous breathing?
What is it during during positive-pressure ventilation?
2:1
1:1
*When on vent, need higher minute ventilation than during spontaneous ventilation to achieve the same PaCO2.
PaCO2 ≥ PETCO2 unless the patient inspires/receives…
exogenous CO2
The difference between PaCO2 and PETCO2 is due to…
dead space ventilation
The most common reason for an acute increase in dead space ventilation is…
decreased cardiac output
What happens with reduced functional residual capacity (FRC)?
-tachypnea (reduced lung compliance )
-arterial hypoxemia (venous admixture increases)
The thoracic cage is shaped like…
a truncated cone
small superior aperture
larger inferior opening (attaches to diaphragm)
Thorax
horizontal plane that passes through the vertebral column at…
T4 or T5
Thorax
The horizontal plane separates which two structures?
the superior from the inferior mediastinum
During ventilation, the upper thoracic diameter mostly changes in the ____ direction & the lower thorax changes in the ____ direction.
thoracic diameter changes:
upper thorax: anteroposteriorly
lower thorax: lateral/transverse
Work of breathing is the energy expenditure of ___.
ventilatory muscles
Ventilatory muscles are ____ muscles. They are susceptible to ____.
endurance
fatigue
Some causes of respiratory fatigue
inadequate oxygen delivery
poor nutrition
increased work secondary to COPD with gas trapping or increased airway resistance
ventilatory muscles (7)
- diaphragm
- intercostal muscles
- abdominal muscles
- cervical strap muscles
- sternocleidomastoid muscles
- back muscles
- intervertebral muscles of the shoulder girdle
The diaphragm performs most of the muscle work during….
nonstrenuous breathing
Exhalation is usually (active/passive).
passive
Patients with c-spine injurty rely on which muscles to breathe?
rely on abd & back muscle
the cervical strap muscles are not working
(Increased work of breathing)
Initial increase will require help from ____ muscles. Further increase in WOB recruits ____ muscles. Maximal work incorporates ____ muscles.
Initial: abdominal muscles rib depression, forced exhalation (felt as rib pain when atheletes forcibily exhale)
Further: cervical strap muscles(elevate sternum & upper chest = optimize thoracic dimensions)
Maximal work: back & paravertebral muscles of the shoulder girdle
Most powerful muscles of expiration
muscles of the abdominal wall
ie: coughing
____ twitch muscles are most susceptible to fatigue.
fast
(“the fast and fatigued”)
What creates negative pressure in the intrapleural space?
diaphragm descends
ribcage expands
Functional residual capacity (FRC)
Definition
The volume of gas remaining in the lungs at PASSIVE end-expiration
created by equal and opposing forces at end-inspiration
At FRC, the intrapleural space has a slightly subambient pressure of…
-2 to -3 mmHg
The 3 divisions of lung parenchyma
Which airway division is responsible for bulk gas movement?
conductive
T/F
Gas exchange occurs in the transitional airways.
True
Transitional airways: gas movement, limited gas diffusion and exchange.
T/F
Gas exchange occurs in the smallest respiratory airway.
True
the primary function of the smallest respiratory airways is gas exchange
The trachea is part of the ____ airway division.
conductive
(T/F)
The transitional airway division contains the alveolar sacs.
False.
The respiratory airway contains the alveolar sacs.
The transitional airway division contains the alveolar ducts.
Which airway are the alveoli located in?
Respiratory
Alveoli and their sacs are in the respiratory airway.
R & L Mainstem bronchi
Which bronchus has the greater diameter?
Angles of each?
Which has longer length before the branching point?
right bronchus has larger diameter
right bronchus leaves the trachea at 25 degrees (less acute)
left bronchus is about 45 degrees.
right main bronchus ~2.5 cm long
left main bronchus ~5 cm
T/F
In all populations, endobronchial intubation and aspiration are more likely in the right bronchus.
False
<3 Y/O: bronchi angles are about equal (55 degrees)
Dr H: “it’s a crapchute where it goes”
The last airway component incapable of gas exchange
bronchioles
First site in the tracheobronchial tree where gas exchange occurs?
respiratory bronchiole
note how it follows the terminal bronchiole
(you’d think terminal means last but w/e)
Alveolar sacs open into what structure?
alveolar clusters
terminal bronchiole > respiratory brionchiole (gas exch starts) > alveolar ducts > alveolar sacs > alveolar clusters
Alveolar-capillary membrane has two primary functions. What are they?
- transport of respiratory gases (oxygen and carbon dioxide)
- production of a wide variety of local and humoral substances
“I’m good at 2 things: breathing and being hormonal”
Surfactant
keeps alv. membrane open
needed for gas exch.
Pulmonary Vascular System Flow
mixed-venous blood RV –> pulmonary capillary bed via two pulmonary arteries
gas exchange occurs in the pulmonary capillary bed
blood is returned to the left atrium via four pulmonary veins
How many pulmonary arteries do we have? how many veins?
2 arteries
4 veins
looks like we prioritize transport of O2 rich blood
What provides oxygen to the conductive airways and pulmonary vessels?
The bronchial arterial system
similar to how the heart has coronary arteries
What determines the lung’s response to external forces?
two main characteristics:
1. ease of elastic recoil of the chest wall
2. resistance to gas flow within airways
Response = recoil & resistance
“R & R”
The natural tendency of the lungs is to…
collapse due to elastic recoil
Older people have (more/less) recoil.
Less recoil
Asthma (increases/decreases) airway resistance.
increases
Physiologic work of breathing includes which types of work? What are they for?
elastic work (inspiratory work; overcome the elastic recoil of the pulmonary system)
resistive work (work to overcome resistance to gas flow in the airway)
What is shown from the pressure-volume relationship of the thorax and lungs?
how normal breathing relates pressure (Vt) to curves when illness affects breathing
Pressure-volume relationship of thorax and lung results in a ___ curve
sigmoidal
How do we find FRC on a pressure-volume relationship?
vertical line drawn at end-expiration coincides with FRC
(Pressure-volume relationship)
Humans breathe on which part of the sigmoid curve? What does this tell us?
The steepest part
shows total lung capacity
(Pressure-volume relationship)
What causes right shift of the compliance curve?
restrictive Dz (less FRC and Vt)
Restrictive = Right shift
T/F
Decreased lung compliance = larger FRC.
False
Decreased lung compliance results in lower FRCs.
Compliance inversely r/t elastic recoil
High compliance = pliable
ie: grocery bag; easy inflation, no elastic recoil
Low compliance = stiff
ie: thick balloon; hard to inflate, high elastic recoil
Increase lung compliance requires (less/more) elastic work to inspire & have (increased/decreased) elastic recoil. This ultimately leads to….
higher compliance:
-less elastic work to inspire
-decreased elastic recoil
result: larger than normal FRC (gas trapping)
High compliance lung = plastic bag
What can cause active exhalation?
high FRC & compliance; gas trapping
COPD & asthma
active exhalation: must use ventilatory muscles to exhale
Diseases characterized by high compliance
COPD
acute asthma
Gas trapping is seen in elevated ____.
FRC
⭐️
What do we need to measure to determine compliance and inspiratory elastic work per breath
airway pressure (Paw)
intrapleural (Ppl) pressure
tidal volume
Laminar Flow Characteristics
-zero velocity at container wall
-maximum velocity at the center of the advancing “cone”.
-conical front: some fresh gas reaches the end of the tube before its completely filled
Laminar flow in the airways allows…
alveolar ventilation even when the tidal volume (Vt) is less than anatomic dead space
(conical front: some fresh gas reaches the end of the tube before its completely filled)
Which type of flow is audible? Which is inaudible?
Audible: turbulent
Inaudible: laminar
Four conditions that will change laminar flow to turbulent flow
- high gas flows
- sharp angles within the tube
- branching/irreg shape in the tube
- decrease in tube diameter
Relationship between resistance and gas flow rate in laminar and turbulent flow
laminar flow
⬆️ resistance = ⬇️ flow rate. (inversely proportional)
turbulent flow
⬆️ flow rate = ⬆️ resistance significantly in proportion
The conscious subject can detect small increases in…
inspiratory resistance
The normal response to increased inspiratory resistance is…
increased inspiratory muscle effort
little change in FRC
An asthmatic pt is showing increased PaCO2 in the setting of increased airway resistance. What does this tell us?
the patient’s compensatory mechanisms are nearly exhausted
acute ventilatory failure!
asthmatic pts can usually compensate for increased airway resistance and keep their paCO2 in the lower normal range
Can asthmatic pts compensate for increased airway resistance? What happens to their PaCO2?
Yes
PaCO2 stays in the low normal range
***PaCO2 = measured the partial pressure of carbon dioxide in arterial blood.
Increased airway resistance may indicate/result from…
BRONCHOSPASM
musocal edema/plug
epitheal desquamination
tumors
foreign bodies
How does recoil affect FRC?
less recoil = high FRC (and residual volume)
How does compliance affect WOB?
diminished compliance of the chest wall = increased WOB
“Noncompliant pts are more work”
Age related changes in respiratory fxn
decreased recoil (elastance)
increased residual vol
increased FRC
decreased chest wall compliance (higher WOB)
usually normal gas exch at rest & exertion
modest decrease in PaO2
no change in PaCO2
decreased sensitivity to hypoxemia and hypercapnia; blunted ventilatory response when challenged by heart failure, airway obstruction, or pneumonia
⭐️
Breathing
act of inspiring and exhaling
requires energy for muscle work
limited by energy reserves
⭐️
Inhalation induction would be (ventilation/respiration).
ventilation
⭐️
Ventilation
movement of gas in and out of the lungs
⭐️
Respiration
- energy is released from organic molecules
- dependent on the movement of gas molecules (CO2 & O2) across membranes
⭐️
humans breathe to _____ and ventilate to ______.
we breathe to ventilate
we ventilate to respire
⭐️
Eupnea
good breathing!
continuous inspiratory and expiratory movement without interruption
⭐️
Apnea
“No breathing”: cessation of ventilatory effort at passive end-expiration (lung volume = FRC)
⭐️
When is lung volume equal to FRC?
during apnea
⭐️
Apneusis
TB definition: Cessation of ventilatory effort with lungs filled at TLC
Google: prolonged, gasping inhalations followed by extremely short and inadequate exhalations.
⭐️
Apneustic ventilation
Apneusis with periodic expiratory spasms
Dr. H: full lungs w/ periodic exp. spasms
⭐️
Biot
Ventilatory gasps interposed between periods of ventilation apnea; also “agonal ventilation”
biot = ‘bouta meet Jesus
Where are the most basic ventilatory control centers?
medulla oblongata
Dorsal Respiratory Group (DRG)
pacemaker for respiratory system
source of elementary ventilatory rhythmicity
“PACE the DRG so you don’t kill the pt”
ventral respiratory group (VRG)
ventral medullary reticular formation
serves as the expiratory coordinating center
How do DRG and VRG control breathing?
-DRG= impulse to inspire
-inspiration occurs
-DRG impulse quenched by a reciprocating VRG impulse
-VRG prohibits further use of the inspiratory muscles
-passive expiration
pneumotaxic respiratory center
limits the depth of inspiration
“the PNEUMOTAXI will take us this DEEP into the city”
peripheral chemoreceptors are composed of…
the carotid and aortic bodies
Where are the carotid bodies? What do they do?
located at the bifurcation of the common carotid artery
predominantly ventilatory effects
How do the carotid bodies control ventilation?
- reaches the central respiratory centers via the afferent glossopharyngeal nerves
- stimulated by decreased PaO2
-PaO2 must reach 60 to 65 mmHg to increase neural activity to substantially augment minute ventilation
“C.I.M.V. (Candy in my van)
Carotid Bodies Increase Minute Ventilation”
During withdrawal of mechanical ventilatory support in a patient who depends on hypoxic ventilatory drive, the PaO2 must fall to less than __ mmHg for spontaneous ventilation to resume.
65
When do the carotid bodies increase minute ventilation?
PaO2 must decrease to 60-65 mmHg
80% of the ventilatory response to inhaled carbon dioxide originates in the…
central medullary centers
Acid–base regulation involving carbon dioxide, H+, and bicarbonate is related primarily to…
chemosensitive receptors located in the medulla
(central chemoreceptors)
Central Chemoreceptors characteristics
-ventilatory response to inhaled anesthetics
-acid-base regulation
-sensitive to ECF H+ [ ]
(Acid-base regulation)
Carbon dioxide has a potent but indirect effect by reacting with water to form ____, which dissociates into ___ & _____ ions.
CO2 + H2O = carbonic acid
carbonic acid dissociates –> H & bicarb ions
Which passes readily through the blood–brain and blood–CSF barriers?
CO2
H+
Carbon dioxide
Which is a more potent ventilatory stimulus?
-acute increase in PaCO2
-acute increase in arterial H+ [ ] from a metabolic source
An acute increase in PaCO2
Carbon dioxide, but not H+, passes readily through the blood–brain and blood–CSF barriers
What are the ventilatory responses to changes in PaCO2?
Onset?
Duration?
increased Vt
increased respiratory rate
rapid; peaks within 1 to 2 minutes after an acute change in PaCO2
increase in ventilation declines over a period of several hours (if CO2 stimulant persists)
Desaturation in a healthy patient takes how long? De-nitrogenating buys us how much time?
3-4 mins
wash out nitro can buy us 10 mins of apnea (in healthy pts)
Breathing 100% oxygen prior to breath-holding
-how long can pt be apneic?
2 to 3 minutes
or
until PaCO2 rises to 60 mmHg
⭐️
Innervation of the Larynx
2 Branches of the Vagus Nerve innervate the Larynx
Superior Laryngeal Nerve
Recurrent Laryngeal Nerve- supply all of the Intrinsic Muscles of the larynx (except the cricothyroid)
SCAR
Super laryngeal
Cricothyroid muscle
All other muscles
Recurrent Laryngeal
Hyperventilation with 100% FiO2 extends the apenic period from ___ minutes to ___ minutes.
3-4
6-10
The rate of PaCO2 rise in awake, preoxygenated adults with normal lungs who hold their breath without previous hyperventilation is ___ mmHg/min in the first 10 seconds, ___ mmHg/min in the next 10 seconds, and ___ mmHg/min thereafter.
7
2
6
⭐️
What causes the CO2 rise in apneic patients under general anesthesia?
“breath-hold” at FRC rather than at vital capacity, which tends to accelerate the rate of PaCO2 rise
However, CO2 rise is still slower than awake state
⭐️
PaCO2 rises in apneic anesthetized patients is __ mmHg during the first minute and __ mmHg/min thereafter
12
3.5
⭐️
Which pt would have a faster rise in CO2? Why?
-apneic under general anesthesia
-pre-oxygenated, awake
Rate of rise of PaCO2 in apneic anesthetized pt is slower than awake state
metabolic rate and carbon dioxide production are significantly less when under anesthesia
lower rate of PaCO2 rise under anesthesia.
T/F
If pt is refusing supplemental O2, hyperventilation with room air can be performed.
False
hyperventilation before prolonged breath-holding can cause loss of consciousness due to arterial hypoxemia
blow off all CO2 = no stimulus to breathe
Is it okay to give aggressive intermittent positive-pressure breathing treatments for patients with COPD?
Nah (if they have a carbon dioxide–based ventilatory drive)
it can depress minute ventilation sufficiently to create arterial hypoxemia
T/F
Lung capacities are based on weight.
False
height
Capacities are composed of….
2+ lung volumes
Tidal Volume (Vt)
volume of gas that moves in and out of the lungs during quiet breathing
~ 6 to 8 mL/kg
“tidal volume; think of tides moving in AND out”
What would decrease tidal volume (Vt)?
decreased lung compliance
reduced ventilatory muscle strength
less flexibility and strength = less Vt
Vital capacity (VC)
Definition
Normal value
Google: the volume of exhaled air after maximal inspiration
60 ml/kg
can vary ~20% in healthy ppl
deep breathing and effective coughing. It is decreased by restrictive pulmonary disease such as pulmonary edema or atelectasis
What would decrease vital capacity (VC)?
restrictive pulmonary disease
-pulmonary edema
-atelectasis
mechanically induced, extrapulmonary restriction:
-pleural effusion
-pneumothorax
-pregnancy
-large ascites
-ventilatory muscle weakness
Things that would press against you exhaling
Inspiratory capacity
largest volume of gas that can be inspired from the resting expiratory level
decreased: significant extrathoracic airway obstruction; obesity
“relax. now take the deepest breath you can”
Residual volume
gas remaining within the lungs at the end of forced maximal expiration; cannot get any more air out
(Residual=what’s left over)
The 2 fxns of FRC on curve
1.resting ventilation on the pulmonary volume–pressure curve
2.elastic pressure–volume relationships in the lung
greatly influences ventilation–perfusion relationships within the lung!
primary determinant of oxygen reserve in humans when apnea occurs
FRC
resting expiratory volume of the lung
FRC
What can FRC tell us (not regarding the curve)
-quantify the degree of pulmonary restriction
-primary determinant of oxygen reserve in humans when apnea occurs
-resting expiratory volume of the lung
Reduces FRC
acute lung injury
pulmonary edema
pulmonary fibrotic processes
atelectasis
(these also reduce compliance)
pregnancy
obesity
pleural effusion
posture
The ____ decreases 10% when a healthy subject lies supine.
FRC
T/F
COPD increases compliance.
True
due to gas trapping
lungs recoil less forcibly
Gas Trapping
retain an abnormally large volume at the end of passive expiration
Forced vital capacity (FVC)
volume of gas that can be expired as forcefully and rapidly as possible after maximal inspiration.
Normally, FVC is equal to vital capacity
FVC may be reduced in…
-chronic obstructive diseases (even if vital capacity is ~normal).
-restrictive diseases
FVC values lower than __ mL/kg are associated with an increased incidence of post-op pulmonary complications (PPCs).
15
and its your fault ;)
Forced expiratory volume (FEVT)
Definition
what does it tell us?
forced expiratory volume of gas over a given time interval during the FVC maneuver
Dr. H: the most gas you can exhale over a time period
-measures flow and severity of airway obstruction!
The most important application of FEVT is…
The most common FEVT?
its comparison with the patient’s FVC
normal: expire 75%+ of FVC in one second
most common: FEVT1 (1 second)
Normal results for FEVT
0.5 sec: expire 50% to 60% of FVC
1 sec: 75% to 85%
2 sec: 94%
3 sec: 97%
tldr: normally, we can forcibly expire nearly all FVC in ~3 secs
reduced= obstructive Dz
FEF25%–75%
“maximum mid-expiratory flow rate”
average forced expiratory flow during the middle half of the FEV maneuver
length of time required for a subject to expire the middle half of the FVC is divided into 50% of the FVC.
Airway management always begins with…
A thorough airway-relevant history and physical examination.
Preoxygenation is also known as…
denitrogenation
should be practiced in all cases when time allows
What is the goal of direct laryngoscopy?
direct line of sight to the larynx
Videolaryngoscopy
mimics direct laryngoscopy, but places an imaging device toward the distal end of the laryngoscope blade
moves the provider’s point of view past the tongue, avoiding the need for a direct line of sight to the glottis
Steps for favorable airway outcome
(1) thorough airway history and physical examination
(2) direct or indirect laryngoscopy
(3) preinduction plan that includes supraglottic ventilation (e.g., facemask supraglottic airway [SGA])
(4) aspiration risk
(5) risk of failed airway maneuvers
Airway
refers to the upper airway
-nasal cavity
-oral cavities
-pharynx
-larynx
-trachea
-principal bronchi
Say pharnyx/larnyx so we can see Dr. H throw the shoe!
The airway in humans is primarily a ___ pathway.
conducting
We want our thyromental distance to be…
3+ finger breadths
The laryngeal skeleton consists of ___ cartilages. It houses the ___.
nine (3 paired; 3 unpaired)
vocal folds
⭐️
Movement of the laryngeal structures are controlled by…
two groups of muscles:
extrinsic muscles- move the larynx as a whole
intrinsic muscles- move the cartilages in relation to one another
⭐️⭐️⭐️
The larynx is innervated by the…
superior and recurrent laryngeal nerves (branches of the vagus nerve)
⭐️
Supplies all of the intrinsic muscles of the larynx (with the exception of cricothyroid muscle)
Recurrent
SCAR
Superior laryngeal nerve
Cricothyroid
All other muscles
Recurrent laryngeal nerve
Unilateral recurrent laryngeal nerve injury
hoarseness
aspiration risk!
Bilateral laryngeal nerve injury
risk complete airway obstruction due to fixed cord adduction (surgical emergency)
Cricothyroid membrane (CTM)
where it at
what it do
1 to 1.5 fingerbreadths below the laryngeal prominence (thyroid notch)
below thyroid cartilage & above cricoid cartilage
coverage for cricothyroid space
Any incisions or needle punctures to the CTM be made in…
its inferior third
directed posteriorly (a posterior probing needle will strike the back side of the ring-shaped cricoid cartilage)
How long is the adult trachea?
where does it end?
15 cm
ends @ t5; carina
bifurcates into R & L principal bronchi
Which bronchi deviates from the sagittal plane at a less acute angle?
right principle bronchus
part of why accidental intubation and aspiration are more common here
Edentulous patients pose what challenge to airway management?
(no teeth)
difficult mask ventilation
Thyromental distance reflects…
neck mobility
degree of retrognathia (bull-dog look)
remember, we want 3 finger breadths!
Thyromtental distance: tip of mentum to thyroid notch in neck-extended position
Mallampati grade
Describes the relationship between mouth opening, tongue size, and pharyngeal space
predicts ease of laryngoscopy
Vocal folds
extends from the thyroid cartilage to arytenoid cartilage
Thyroid cartilage
Shield shaped; protects vocal mechanism from the anterior aspect
Increases aspiration risk
GERD not responsive to medication
pregnancy >12 wks
post partum <2 days
frequent pneumonia(could be from frequent aspiration!)
voice changes
hiatal hernia
diabetic (gastroparesis)
vocal cord polyp
acute narcotic therapy
What airway should be used for pts with increased aspiration risk?
ETT
the truly secure airway bc of the balloon blocking passage
How do we measure thyromental distance
distance measured from tip of mentum to thyroid notch in neck-extended position
Mallampati I
Can see:
tonsillar pillars
uvula
full view soft palate
Mallampati II
Can see:
upper uvula
soft palate
Mallampati III
Can see:
soft palate
Mallampati IV
Can see:
hard palate only
Mallampati score?
II
Mallampati score?
IV
can see hard palate only
Mallampati score?
III
can see soft palate
Cannot see uvula or its upper portion
Common assessments of airway
thyromental distance
mouth opening
mallampati
head & neck mobility
ability to prognath- bring lower teeth in front of top teeth; jaw mobility
Airway concerns for Down Syndrome
Poorly developed or absent bridge of nose
Macroglossia
Microcephaly
C-spine abnormalities
Ariway concerns for Pierre Robin Syndrome
Micrognathia (lower jaw (mandible) is smaller than normal)
Macroglossia
Cleft Soft Palate
Is the LMA a secure airway?
No; only ETT is
Barriers to proper mask ventilation
beard
sleep apnea
neck radiation
>55 Y/o
no teeth
obese
BONES (beard, obese, no teeth, elderly, sleep apnea)
De-nitrogenating can replace up to 95% of the ____ with ___ to provide an apneic reservoir.
FRC
oxygen
Does nitrogen pass thru alveoli?
No
Before induction, etO2 should be at least
90
etO2 NOT etCO2
Several minutes of preoxygenation with 100% O2 via a tight-fitting facemask may support at least __ minutes of apnea before desaturation occurs.
8
What happens if mask straps are too tight?
facial nerve (CN VII) ischemia
compresses buccal branch of CN VII
⭐️
A patient with normal lung compliance should require no more than ___ pressure for lung inflation, as measured on the anesthesia circle manometer.
20-25 cm H2O
higher can cause belly expansion –> regurg
Nasal airways
Pros and Cons
less likely to stimulate coughing, gagging, or vomiting in the lightly anesthetized patient
may cause epistaxis
Inability to mask ventilate could mean that your patient is experiencing…
laryngospasm, a local reflex closure of the vocal folds
-foreign body (e.g., oral or nasal airway)
-saliva
-blood
-vomitus
…..touching the glottis.
Laryngospasm
definition
causes
reflex closes the vocal folds
may be triggered by a foreign body (e.g., oral or nasal airway), saliva, blood, or vomitus touching the glottis
Laryngospasm
consequences
treatment
Hypoxia
noncardiogenic (negative pressure) pulmonary edema (if pt ventilates against closed vocal cords/ other obstruction)
Treatmeant:
-remove offending stimulus
-oxygen with continuous positive airway pressure (CPAP),
-deepen the anesthesia (IV)
-if unsuccessful, use rapid-acting muscle relaxant
Early extubation may cause…
noncardiogenic (negative pressure) pulmonary edema
Laryngeal Mask Airway (LMA)
positioning
inflation
fit
-in hypopharynx with the opening overlying the laryngeal inlet
-distal tip in the esophageal inlet, it does not reliably seal it
-cuff fills hypopharyngeal space = seal allows positive pressure ventilation up to 20cm of H2O pressure
-Adequacy of the seal is dependent upon correct placement and appropriate size
Supraglottic Airway (SGA)
ABOVE the vocal cords
T/F
LMAs protect against aspiration.
False
Advantages of using LMA
-can give oxygen until complete restoration of airway reflexes
-reduced risk laryngospasm
-less aspiration risk than mask ventilation
-reduced cardiovascular responses
-reduced coughing on emergence
-Reduced intraoperative bronchospasm
SGA removal
when to remove?
when not to remove?
-deeply anesthetized or
-after protective airway reflexes have returned and the patient is able to open the mouth on command
DONT REMOVE:
during excitation stages of emergence –> coughing, laryngospasm
Confirming airway placement
-chest rise
-ausc
-etCO2
-condensation
“piece of C.A.E.C.”
and watch it go into vocal cords ofc
SGA contraindications
-high aspiration risk
-full stomach/hiatus hernia
- significant GERD
-bowel obstruction
-delayed gastric emptying
-unclear history
-muscle relaxant
-laparoscopic surgery
CORDS (C-spine injury, obstruction, restricted mouth opening, distorted airway, stiff lungs)
Tracheal Intubation
Before any case, what do we need?
Oxygen (ambu)
Suction
Stimulation of _____ will cause vagal reactions. These include…
The Internal Branch of the Superior Laryngeal Nerve
laryngospasm
bradycardia
hypertension
Mac blade
-curved
-displace epiglottis out of the line of sight
-placed anterior to epiglottis into the vallecula
-should not contact the epiglottis while lifting!
-tenses of the glossoepiglottic ligament
Mac blades are curved like the “c” in “Mac”
A= mac
B = miller
Miller blade
-straight
-reveals the glottis by compressing the epiglottis against the base of the tongue
-blade is placed over (posterior to) the epiglottis
-DOES contact epiglottis while lifting
A= mac
B = miller
We sweep the tongue to the (right/left).
left
Which blade is better to use if there is little room to pass a tube (small mouth)?
Mac
“a small macintosh apple”
A= mac
B = miller
Better blade for anterior airways
Miller
A= mac
B = miller
The tracheal tube cuff should be placed…
advance it 2 cm past the glottic opening for midtracheal placement
ETT sizing for men and women?
When is larger sizing appropriate?
Men 8-9
Woman 7-8
“why was 6 afraid of 7?”
“Cause 7, 8, 9!”
use larger sizing for bronchoscopy
T/F
Gastric intubation will not show CO2 values.
False
CO2 can come from the stomach; ie: pt had a soda; if we’ve ventilated the belly
Use your ____ hand to hold the laryngoscope.
left
Just a gentle reminder to NEVER TAKE YOUR EYES OFF THE CHORDS
⭐️
Extubation criteria
-Return of Consciousness
-Spontaneous Respiration
-Resolution of Neuromuscular Blockade (sustained tetany – 5 sec)
-follow commands
-Sustained Head lift for 5 seconds
-Sustained hand grasp
-Spontaneous Tidal Volume >6cc/kg
-Negative Inspiratory Pressure > 20cm H2O
Which practice of anesthesia is considered benign?
none lol
Which nare do we attempt to intubate first?
right
ASA definition of difficult airway
situation in which the conventionally trained anesthesiologist experiences difficulty with mask ventilation of the upper airway, endotracheal intubation, or both
Considerations of difficult airway management
difficulty of the patient’s airway in terms of:
-Laryngoscopy and Intubation
-Supraglottic Ventilation Techniques
-Aspiration Risk
-Apnea Tolerance
Start ASA difficult airway algorithm at which 2 root points?
-awake intubation
-Intubation attempts after Induction of General Anesthesia
T/F
The difficult airway algorithm can only be applied to difficult airways.
False
relevant in ALL instances where the airway is managed!
Awake intubation would be good for which situations?
airways we only get one shot at
Ludwig’s angina
angioedema
epiglottitis
Can you give sedation for an awake intubation?
Yes! but very little
transtracheal block (local anes)
If awake intubation doesnt work, what do we do?
must use judgement: cancel case vs. consider other options vs. invasive airway.
Use invasive airway if surgery is vital to survival
⭐️
Regional Anesthesia with a Difficult Airway:
When to use and when not to?
can use regional with difficult airway depending on situation
consider toxicity if large dose is needed (extensive neuraxial local anesthetic)
Awake airway management
Sedation can be used to decrease patient anxiety (small doses of benzos maintain spont Respirations)
Anti-sialagogues administered (dry up secretions)
Vasoconstriction of nasal passages
Supplemental Oxygen during the procedure
My drug-addicted patient when I tell him he’s getting cocaine for his nasal intubation
-highly effective local anesthetic & a potent vasoconstrictor
-4% solution applied to mucosa
-max dose 200mg in adults
Lidocaine
onset
preparations
administration
Applied topically- 15min peak onset
Injectable/Topical solution- 1%,2%, 4%
Viscous solution- 1%, 2%
Ointment- 1%, 5%
Aerosol- 10%
Adminstration:
inject into trachea (air aspiration to confirm location)
push hard to induce coughing, which distributes the medication
____ are a cornerstone of awake airway management.
local anesthetics
Benzocaine
onset /duration
preparations
toxic dose
Rapid Onset & Short Duration
Available in 10%, 15% & 20% solutions
Hurricane spray- Benzocaine + Tetracaine
half-second spray delivers 30mg of benzocaine
toxic dose is 100mg
Cetacaine spray
Benzocaine + tetracaine, butyl aminobenzoate, benzalkonium chloride and cetydimethyl ammonium bromide
May produce methemoglobinemia(treat with methylene blue)
*methemoglobinemia: diminution of the oxygen-carrying capacity of circulating hemoglobin; conversion of iron species
Nasopharynx is innervated by…
greater and lesser Palatine Nerves (nasal turbinate & most of the septum)
(Palatine nasal nerves–>Palpatine and his big nose)
How long should cotton-tipped applicators stay in place for nasal anesthetics?
5-10 mins
The Pharynx/ Base of the Tongue is
Innervated by…
branches of the Vagus, Facial & Glossopharyngeal
How to administer local anesthetics to pharynx/base of tongue
aerosolization or “swish & swallow”
What kind of nerve block is done for the Hypopharynx/ Larynx/ Trachea?
Superior Laryngeal Nerve Block
Contraindications to Fiberoptic Bronchoscopy
Hypoxia
Heavy Airway Secretions- not relieved with suction or anti-sialagogues
Bleeding from the Upper or Lower Airway- not relieved with suction
Local Anesthetic Allergy (for awake attempts)
Inability to Cooperate (for awake attempts)
Which route is “easiest” for fiberoptic bronchoscope?
nasal
The glidescope is a brand name. It performs…
video laryngoscopy
Their Laryngoscope blade 60 degree angle. Its good bc:
-Similar technique as conventional DL
-Video display team can see
-Less stress on the airway (Dr. H calling BS on this)
Retrograde Wire-Aided Tracheal Intubation procedure
“last ditch effort”
Inject local anesthetic over mid-cricothyroid membrane (18 guage)
45 degree angle to the chest
aspirate air
guidewire sheath is advanced into the trachea
advance wire until the wire emerges from the mouth
7.0 OET placed over the guidewire into the trachea
Check tube placement
Remove guidewire
Airway Bougie
-semimalleable
-stylets
may be blindly manipulated through the glottis when a poor laryngeal view is obtained
-“clicks” as it touches tracheal rings; you’re in!
⭐️
Percutaneous Transtracheal Jet Ventilation (PTJV)
“Jet Ventilator”
“CANNOT INTUBATE/ CANNOT VENTILATE” situation
An IV catheter (12,14 or 16 gauge)- attached to a 5ml syringe (empty or filled with local)
Once in the airway remove the sharp
Attach the luer-lock of the jet ventilator to the Angio Cath
“twinkle twinkle little star” (each syllable) = tempo for delivering breaths
⭐️
NPO guidelines
-clears 2H
-breast milk 4H
-nonhuman milk 6H
-light meal 6H
-fatty meal/meats 8H+
Intubating LMAs
when to use
how to use
-if RSI fails
-ETT is inserted through the LMA
-use #5 classic LMA for 7.0 ETT (like male to female shoe sizing!)
⭐️
Complications of Retrograde wire-aided intubation (RWI)
bleeding
subcutaneous emphysema
pneumomediastinum
pneumothorax
breath-holding
caudal migration of wire
trigeminal nerve trauma
Complication of Jet ventilation
barotrauma!
Preoxygentation:
Most common reason for not achieving max alveolar FiO2?
loose fitting mask
Preoxygenation:
if pt refuses mask, what else can we do?
Can work around the need for 5 min pre-oxygenation!
Have pt take four vital capacity breaths
Hold LMA in which hand
dominant
(left for laryngoscope and mask)
What are the single and paired cartilages of the larynx?
3 unpaired (single) cartilages: epiglottis, thyroid, cricoid
3 paired catilages: arytenoid, corniculate, cuneiform
Surgical airways
Cricothyrotomy (emergent/temporary)
Tracheostomy
⭐️
Which branches of the vagus nerve innervate the hypopharynx?
Superior laryngeal nerve
Recurrent laryngeal nerve: supplies all of intrinsic muscles of the larynx (except the cricothyroid)
⭐️
The Superior laryngeal nerve provides sensory information from the level of ____ to the ____.
level of the vocal cords to the underside of the epiglottis
What does the recurrent laryngeal nerve innervate in the larynx?
Recurrent laryngeal nerve innervates the supply of all the intrinsic muscles of the larynx except the cricothyroid
Trauma to which laryngeal structure can cause vocal cord dysfxn?
recurrent laryngeal nerve
Cranial nerve ____ is responsible for the gag reflex.
CN IX Glossopharyngeal
Characteristics associated with difficult intubation
Think features of the
Mouth
Teeth
Jaw
Neck
Other common anesthesia assessments
high arched palate
Small mouth opening
long incisors
prominent overbite
retrognathic jaw
inability to sublux jaw
short-thick neck
reduced cervical mobility
Mallampati 3 or 4
short thyro-mental distance
**sublux: partial dislocation of a joint or organ
The sniffing position
cervical flexion, atlanto-occipital extension
oral, pharyngeal, and laryngeal axes into alignment during laryngoscopy
T/F
The mallampati score is a comprehensive airway exam.
False
used alone, it is a poor predictor of a difficult airway
use in addition to other assessments
Laryngeal View grading
*Grade I: Visualization of Entire Glottic Aperture
*Grade II: Visualization of Only Posterior Aspects of Glottic Aperture *Grade III: Visualization of the Tip of the Epiglottis
*Grade IV: Visualization of No More Than the Soft Palate
External anesthesia assessments
Evaluate 3-3-2
-fit 3 fingers between incisors?
-Is the mandible 3 fingers from the mentum to the hyoid bone?
-Is the distance from the hyoid bone to the thyroid 2 fingers?]
sellicks maneuver (cricoid pressure)
How and why do you perform this maneuver?
● The patient is not ventilated
● esophagus is compressed by applying pressure to the cricoid ring against the C5 vertebra.
● apply pressure before LOC & until intubation confirmed
● Pressure before LOC = 20 Newtons or about 2 kg
● Pressure after LOC = 40 Newtons or about 4 kg
crush that cricoid after they’re out cold lol
goal: compress esophagus to prevent regurgitation
Facemask
-use
-flow rate
-how to properly ventilate
-max pressure
● equipment used to preoxygenate patients with 100 oxygen at flow of 10 to 12 L/min
● Successful Mask Ventilation:
-positioning: supine; head and neck in “Sniffing” position
-proper oral/nasal airway size prevents coughing, vomiting and laryngospasm
-hold with left hand
-right hand squeezing bag
-thumb over the mask/bridge of nose
-index over wide edge of the mask near the patient’s chin
-middle, ring and pinky on the bony prominence of patient’s jaw.
NO more than 20-25 cm H20 of pressure to inflate the lungs
Which blade has higher risk of vagal stimulation?
miller blade
bradycardia
Intubation setup
Oxygen source
Ambu bag
oropharyngeal and nasopharyngeal airways
tracheal tubes
stylet
suction
laryngoscope handle (tested before)
laryngoscope blades (MacIntosh and Miller)
Pillow
Towel
Blanket or Foam for head positioning
Stethoscope
How do size an LMA?
pick largest size that will sit comfortably in mouth
Mallampati exam assesses the _____ space.
oropharyngeal
Inter-incisor gap assessment
what does it assess?
why is it important?
assesses ability to open mouth
directly affects ability to align the oral, pharyngeal & laryngeal axes
What does a smaller inter-incisor gap mean?
Whats normal?
smaller gap = more acute angle between oral & glottic openings
normal: 2-3 finger breadths/4 cm
What increases chance of tooth damage?
buck teeth
Laryngoscopy
Displace the tongue into the _____ to expose the glottic opening. What conditions make this more difficult?
submandibular space
tumor, radiation, submandib. abscess
T/F
The transitional airways can perform limited gas exchange.
True
the respiratory airways are not the only airways that can perform gas exchange
A thyromental distance (TMD) of less than ____ or above ___ indicates difficult intubation.
TMD
6< or >9 cm = difficult intubation
Mandibular protrusion test (MPT)
assess TMJ fxn
have pt sublux jaw
compare position of lower incisors to upper
stage 3 = more difficult intubation
(pt cannot extend lower past upper)
Atlanto-occipital joint mobility
importance to intubation
conditions that impair
affects our ability to place pt in sniffing position
impair AO mobility:
-degen. joint Dz
-rheumatoid arthritis
-ankylosing spondylitis
-trauma
-surgical fixation
-klippel-feil
-down syndrome
-DM
The grading system that helps us measure the laryngoscopic view we obtain during direct vision laryngoscopy
Cormack & Lehane score
LEMON
For intubation:
Look externally
Evaluate 3-3-2
Mallampati
Obstruction
Neck mobility
Which traits would demand higher PiP?
poor lung compliance
higher airway resistance
Mendelson Syndrome
risk factors
how to reduce risk
chemical injury caused by the inhalation of sterile gastric contents
risk factors: gastric pH <2.5; gastric volume >25 ml (0.4ml/kg)
clears 2H before surgery: reduces gastric volume; increases gastric pH
Cricoid pressure
complications
- airway obstruction (difficult laryngoscopy, poor glottic view)
- esoph. rupture if pt is vomiting
Angioedema
whats our chief concern?
etiologies?
primary concern: airway obstruction
causes:
-anaphylaxis
-ACE inhibitors
-hereditary
-C-1 esterase deficiency
Anaphylactic angioedema treatment
epi
antihistamine
steroids
-Icatibant (bradykinin receptor antag)
-FFP (enzymes to brkdwn bradykinin)
-C-1 esterase concentrate
-ecallantide (kalikrein inhibitor; stops kininogen–> bradykinin)
ACE inhibitor/C-1 esterase deficiency angioedema treatment
C-1 inhibitor concentrate
FFP
Icatibant
Ecallantide
Ludwig’s Angina
aggressive cellulitis on floor of the mouth
inflammation & edema compress the submandibular, submaxillary and sublingual spaces
primary concern: pushes tongue posteriorly –> complete supraglottic airway obstruction
What happens if the tongue is displaced more posteriorly?
supraglottic airway obstruction
How do we intubate with Ludwig’s angina?
awake nasal intubation
awake trach
Conditions that cause enlarged tongues
Beckwith Syndrome
Trisomy 21 (Downs)
B. T. = big tongue
Conditions that cause small/underdeveloped mandible
Pierre Robin
Goldenhar
Treacher Collins
Cri du chat
P-lease
G-et
T-hat
C-hin
Conditions that cause cervical spine anomaly
Klippel-fiel
Trisomy 21
Goldenhar
“Try Klipping Gold”
The sniffing position aligns which axes?
oral
pharyngeal
laryngeal
Sniffing position includes ___ flexion and ___ extension.
cervical flex
atlanto-occipital extension
Intubation positioning for morbidly obese patients
their body anatomy places chest above the level of the head
HELP position
Head Elevated Laryngoscopy Position
Benefits of the HELP position
unloads diaphragm
may prolong time until desat when apneic
How can head position shift the ETT? (3 positions)
nose to chest = toward carina 2 cm
nose away from chest = away from carina 2 cm
lateral head rotation = away from carina 0.7 cm
Aggressive jaw thrust can damage the _____ nerve. This will show as…
facial nerve
facial sagging, drooling, may affect chewing
Why shouldn’t we leave the ETT connector on the patient’s face?
supraorbital nerve compression
eye pain, forehead numbness, photophobia
An oro/nasopharyngeal airway relieves ____ obstruction by…
upper airway obstruction
moves tongue & epiglottis away from posterior wall of pharynx
How to size an OPA
measure corner of mouth to earlobe OR angle of mandible
flange should protrude outside lips
pharyngeal end should rest at base of tongue
What happens if we use an OPA that is too short? Or one that’s too long?
too short = airway obstruction
too long = displaces epiglottis (obstructs)
airway trauma
How to size a NPA
measure nare to earlobe OR angle of mandible
What happens if we use an NPA that is too short? Or one that’s too long?
too short = won’t relieve obstruction
too long = displaces epiglottis towards glottis; risk trauma
Inserting an NPA in a pt with a cribiform plate injury may cause…
brain injury
Contraindications to NPA
Cribiform plate injury
coagulopathy
h/o transsphenoidal hypophysectomy
h/o Caldwell Luc surgery
nasal fracture
What are these fractures called? What significance do they have to nasal intubation?
Lefort fractures
Nasaltracheal intubation contraindicated in Le Fort II or III fractures (possible cribriform plate involvement)
Cricoid pressure vs. BURP
“BURP” (Backwards Upwards Rightwards Pressure) improve the view of the glottis during laryngoscopy/intubation, rather than to prevent regurgitation (cricoid pressure)
BURP maneuver
larynx is displaced backward (B) against the cervical vertebrae, upward (U, superiorly) and to the patient’s right (R), using pressure (P) over the thyroid cartilage
improves glottic visualization
ETT cuff can cause ischemia if its pressure is….
25+ cm H2O
Tracheal ischemia can occur if the ETT cuff pressure exceeds the ____ pressure.
tracheal mucosal perfusion
Whats the best way to reduce risk of tracheal ischemia?
measure pressure using nanometer
without out, measurement is not accurate
Murphy Eye
small hole opposite of the bevel
provide alternate path of air if ETT tip occludes or is blocked by touching tracheal wall
Low vol, high pressure cuff
vs.
high vol, low pressure cuff
low vol, high prssr:
-better aspiration protection
-less sore throat
-better view when intubating
-prolonged intubation = tracheal ischemia
high vol, lo prssr:
-cuff pressure close to pressure exerted on trachea
-can underestimate pressure
-N2O increases cuff prsr
-OGT/NGT can pass
Pediatric ETT formulas
ETT w/o cuff = (age/4) +4
ETT + cuff = (age/4) + 3.5
depth = Internal diameter x 3
LMA
max PP ventilation
max cuff pressure
max PPV = 20 cm H2O
max cuff = 60 cm H2O (target 40-60)
Video Laryngoscopy
Non-channeled vs channeled
Channeled integrates ETT onto the device
Non-channeled: ETT separate from device
If video laryngoscopy fails, consider…..
awake fiberoptic
Apertures on the LMA
prevents epiglottis from obstructing tube
LMA ___ is the most common cause of nerve damages. The nerves at risk are….
cuff overinflation
lingual hypoglossal
RLN (recurrent laryngeal nerve)
If LMA does not have a good seal…
add air to cuff
LMA sizing
Airway obstruction at or below the ___ is a contraindication for LMA.
glottis
Those at risk for tracheal ___ should not use an LMA.
collapse (tracheomalacia, external tracheal compression)
gastric regurgitation with LMA
leave LMA in place (avoid displace contents already behind it)
Trendelenburg
deep anesthetic
100% O2 ambu unless contents in circuit
low flow & Vt
suction catheter thru LMA
fiberoptic to assess if contents in trachea (if so, consider ETT + aspiration protocol)
LMA with asthmatic pt
less risk of bronchospasm vs. ETT
volatiles can cause aggressive return of resp reflexes on emergence, worsened with ETT b/c it sits in trachea
Volatile anesthetics initially ___ respiratory reflexes, but can cause _____ on emergence.
blunt
coughing/bronchospasm
ETT can intensify response on emergence
Which airway device is least stimulating?
LMA
Direct laryngoscopy can cause _____ stimulation.
SNS
increase catecholamines
HTN
tachycardia
arrhythmia
Bspasm
Combitube
supraglottic
double lumen
difficult airway
blindly placed in hypopharynx
Size 37 (4-6ft) 40-85 ml
size 41 (>6ft) 40-100 ml
distal cuff always 5-12 ml
not for under 4 ft
inflate orophar. first
if in esoph vent thru blue lumen
if in trachea vent thru tracheal lumen
King Tube
blindly inserted
distal cuff obstructs upper esoph.
proximal cuff seals oral and nasal pharynxes
Combi vs King tube
King:
only one ventilation lumen
inflates both balloons at once
child sizes 10 kg +
both have same considerations
both blindly inserted
Gold standard for maintaining difficult airway in awake spont. breathing pt
flexible fiberoptic bronch
How to maneuver fiberoptic scope
Fiberoptic Bronch indications
Gold standard for maintaining difficult airway in awake spont. breathing pt
C-spine limitations: cerv. stenosis/fixation, chiari malformation, vertebral art. insuff
limited mouth opening: TMJ, facial burn, mandib-maxillary fixation
Fiberoptic Bronch contraindications
Absolute: too uncooperative, near total upper arwy obstrutn, massive trauma (unless using retrograde intubation)
Moderate: mildly uncoopertv, obstruction enough to prevent intubation, copious blood/sectrns, hypoxia (not enough time)
Relative: concern for vocal crd damage if ETT is passed over bronchoscope, infxn that may impair sterility, coagpathy, allergy to local anes.
***picture is retrograde intubation
Bullard Laryngoscope
when to use
rigid, fiberoptic
indirect laryngoscopy
Use for:
small mouth opening (minimum 7mm)
impaired C-spine mobility
short/thick neck
treacher collins syndrome
Pierre Robin syndrome
adult + peds sizes
Compared to DVL, the Bullard causes less ___.
cervical spine displacement
Examples of Rigid Fiberoptic devices
Bullard
Wuscope
Upsher
Intubating stylet is also known as ___ & ___.
Eschmann
bougie
A Cormack & Lehane score of __ warrants use of the angled tip (coude) intubating stylet.
3
⭐️
If you don’t feel clicks, but believe you’re in the trachea, assess for the ___ sign. If you dont feel this, then you are in the ____.
Hold up sign
advance bougie to 45 cm max
stop when increase in resistance
bougie becomes lodged in the smaller airways
bougie stops at carina
no sign = esophagus
If ETT catches on larynx soft tissue, rotate it ___ degrees (clockwise/counterclockwise). This will orient the bevel ____.
90 degrees
counterclockwise
posteriorly
T/F
Lighted stylets can be used for blind intubation.
True
transilluminate anterior neck to facilitate intubation
How do we know if the lighted stylet is in the trachea?
well-defined circumscribed glow
A= trachea
B = esophagus (diffuse; no circum. glow)
Lighted Stylet
Pros
Cons
Pros:
-anterior airways
-small mouth opening
-minimal neck manipul8n (C-spine issues, pierre-robin)
-less stimulating/sore throat than direct laryn.
-oral/nasal intubation
Cons:
-short/thick neck difficult
-not for emergent/cant intubate/cant ventilate (use jet vent for this)
-blind technique! (no tumors, foreign body, airway injury, epiglottitis)
-not for traumatic laryngeal airway
Retrograde intubation is a ____ procedure. ETT is passed….
BLIND
over a wire
⭐️
Steps for Retrograde intubation
- Puncture Cricothyroid membrane (14 - 18g needle)
- Aspirate air = inside tracheal lumen
- Pass a wire through the needle and advance it in a cephalad direction.
- The wire should travel in-between the vocal cords exit thru the mouth
- Load the endotracheal tube over the wire
- Once the ETT is in the trachea and cannot be advanced any further, withdraw the wire
- advance the ETT to final position
Needle gauge for retrograde intubation
14-18 G
indications for retrograde intubation
-unstable C spine (most common)
-upper airway bleeding (can’t see glottis)
-failed intubation but ventilation possible (allows for time needed)
Can retrograde intubation be performed on awake patient?
yes!
that’s gotta be a horrible day
contraindications for retrograde intubation
Anatomy:
-neck flexion deformity (can’t access CTM)
-severe obesity (unable to identify landmarks)
-Pretracheal abscess/mass (goiter)
Laryngotracheal Dz:
-trach. stenosis under punctr site
-tumor in wire path
-coagulopathy
⭐️
complications for retrograde intubation
-bleeding
-pneumomediastinum
-pneumothorax
-trigeminal nerve trauma
-breath holding
-wire goes in wrong direction
**Pneumothorax = air leaks between lung & chest wall or visceral & parietal pleura
**Pneumomediastinum = air in the mediastinum
The surgical airways include….(3)
EMERGENCY:
1. Percutaneous cricothyroidotomy with transtracheal jet ventilation
2. Surgical cricothyroidotomy
controlled situation:
3. Tracheostomy
Percutaneous cricothyroidotomy with transtracheal jet ventilation
inserting a large-bore needle through CTM
ventilate with high-pressure oxygen source (ie: jet ventilator)
CTM =cricothyroid membrane
Jet ventilation requires a high-pressure oxygen source, about ___ psi during ___.
50 psi
inhalation
Airway obstruction in jet ventilation
can prevent exhalation
contraindication!
Surgical Cricothyroidotomy
small, horizontal incision in cricothyroid membrane (percutan uses large bore needle)
insert cuffed ETT
Contraindications for tracheostomy
nun
Surg. Cricothyroidotomy contraindications
-challenging prediatric cricothyroidotomy (more pliable/mobile larynx)
-Percutan. Cric is best in emergency <6yrs
Surg. Cricothyroidotomy complications
-tracheal stenosis
-trach/esoph injury
-hemorrhage
-disordered swallowing
-SubQ/mediastinal emphysema
The ____ commonly covers the CTM in children.
thryoid isthmus
Percutaneous Cricothyroidotomy contraindications
upper airway obstruction
laryngeal injury
Percutaneous Cricothyroidotomy complications
any obstruction above jet vent tip will prevent exhaling
barotrauma
pnemothor
subQ/mediastinal emphysema
Tracheostomy complications
Acute:
airway obstruction
hypoventilation
pneumo
bleeding
Longterm:
tracheal stenosis
tracheomalacia
tracheoesophageal fistula
tracheal necrosis
Can we extubate patients in a state of consciousness between deep or awake?
no
ExTT when deep or awake, no inbetween
Guedel stage 1
awake, disoriented, airway reflexes intact
Guedel stage 2
light anesthetic plane
hyperactive airway reflex
risk laryngospasm
Guedel stage 3
Deep anesth. plane
airway reflexes weak
Which Guedel stage is associated with risk of laryngospasm
2
Awake ExTT
pros
cons
P
airway intact
maintain their airway patency
lower risk aspiration
C
higher:
CV & SNS stimulation
coughing
ICP
IOP (intra oc prsr)
intra-abd prsr
Deep ExTT
pros
cons
P
less CV, SNS stimulation & coughing
C
ineffective airway reflexes
higher risk obstruction, aspiration
Know the difficult airway algorithm
2022 version
prevent complications of awake extubation
CV & SNS stimulation:
Betablockers
Ca channel blockers
vasodilators
Coughing:
Lidocaine (IV or thru ETT cuff)
opioids
techniques for extubating the difficult airway
- ExTT while fully awake
-extubate over a flexible fiberoptic bronchoscope
-extubate then placeLMA
-airway exchange catheter
Reintubating a difficult airway (post extubation)
AEC is used as a stylet
Seldinger technique (similar to retrograde wire)
https://www.youtube.com/watch?v=27V7puDyMAY
**AEC= airway exchange catheter
The airway exchange catheter (AEC) lumen can be used to…
End-tidal CO2 measurement
Jet ventilation (via Luer lock adapter)
Oxygenation insufflation (via 15mm adapter)
(Re-intubating a difficult airway)
Complications of exchange catheter (AEC)
barotrauma
pnemothorax
inability to replace ETT
Endotracheal tube
PVC
placed between the vocal cords through the trachea
provide oxygen and inhaled gases to the lungs
muscles elevate the sternum
cervical trap muscles
Left shift on the P-V curve signifies…
obstructive Dz
(increased FRC)
____ airflow swirls when going from ___ to ___ area.
Turbulent
large
small
Carotid bodies are part of the (central/peripheral) chemoreceptors.
peripheral
central = medulla
The (central/peripheral) chemoreceptors account for 80% of respiratory response.
central
⭐️
In apneic patients, PaCO2, increases of ___ mmHg in the first minute and ___ mmHg per minute afterwards.
12
3.5
V:P ratio is determined by
FRC
anatomic location of the 1st tracheal ring
anterior to C6
ends at the carina ~T5
T/F
The carina bifurcates into R & L bronchi
False
trachea
Do we bag patients?
Not unless they’re dying
If they’re not dying, we are ventilating them
Its not preoxygenating, its _____.
denitrogenizing
Non-cardiogenic pulmonary edema is the result of…
a spontaneous breath against a
closed glottis
Direct Laryngoscopy
Black lines on ETT should be …
on either side of the vocal cords
Procedures when its best to nasally intubate
facial trauma, jaw wiring, maxillofacial surgery
Awake intubation is best when the patient has which conditions/diagnoses?
Ludwig’s angina
Epiglottitis
angioedema
Onset of topical Lidocaine
15 mins
Easiest route for fiberoptic bronch
nasal
How far in advance of surgery should the pt stop smoking?
2 months
reduces PPC risk
What surgery has highest risk of PPC?
nonlaparoscopic upper abdominal surgery
most important aspect of postoperative pulmonary care and prevention of PPC is…
early ambulation
Reduced FRC ultimately results in…
arterial hypoxemia
low FRC –> venous admixture increases –> arterial hypoxemia
rapid-sequence induction
gain control of the airway in the shortest period of time after the ablation of protective airway reflexes with the induction of anesthesia
Airway access via the extrathoracic trachea may be warranted when…
intubation and mask and SGA ventilation fail
Know the airway approach algorithm
