Airway Management Flashcards
The upper airway consists of the _____.
pharynx, nose, mouth, larynx, trachea, and mainstem bronchi
Functions of the upper airway
warms and humidifies air, filters particulates and prevents aspiration
The nose leads to ____.
the nasopharynx
The mouth leads to ____.
the oropharynx
The epiglottis prevents _____.
aspiration by covering the glottis during swallowing
The larynx is composed of _____.
nine total cartilages
3 unpaired
3 paired
What are the 3 unpaired cartilages of the larynx?
- Thyroid
- Cricoid
- Epiglottis
What are the 3 paired cartilages of the larynx?
- Arytenoids
- Corniculates
- Cuneiforms
The thyroid cartilage shields the _____.
conus elasticus, which forms the vocal cords.
The trigeminal nerve provides ____.
general sensation to the anterior two-thirds of the tongue
The glossopharyngeal nerve is AKA ____ and provides ____.
cranial nerve IX and provides general sensation to the posterior one-third of the tongue, the roof of the pharynx, the tonsils and the undersurface of the soft palate.
The vagus nerve is AKA __ and provides ___.
cranial nerve X and provides sensation to the airway below the epiglottis.
What are the branches of the vagus nerve?
1) The superior laryngeal
2) The recurrent laryngeal nerve
The superior laryngeal is a branch of the _____ divides into ____.
branch of the vagus nerve
an external (motor) nerve and an internal (sensory) branch.
*The internal branch provides sensory supply to the larynx between the epiglottis and the vocal cords.
The recurrent laryngeal nerve innervates ____.
the larynx below the vocal cords and the trachea.
The muscles of the larynx are innervated by the ___.
recurrent laryngeal nerve, with the exception of the cricothyroid muscle, which is innervated by the external (motor) superior laryngeal nerve
Muscles that tense and relax the vocal cords
CricoThyroid: “Cords Tense”
ThyroaRytenoid: “They Relax”
Muscles that abduct and adduct the vocal cords
Posterior CricoArytenoid: “Please Come Apart”
Lateral CricoArytenoid: “Let’s Close Airway”
Damage to the External Branch of the Superior Laryngeal Nerve
Damage to the external laryngeal nerve may paralyze the cricothyroid muscle.
This impacts the vocal cords’ ability to tense and produces a raspy voice.
Unilateral Recurrent Laryngeal Nerve Damage
This injury is characterized by hoarseness and a paralyzed cord that assumes an intermediate position (midway between abduction and adduction).
This is the most common injury after subtotal thyroidectomy.
Bilateral Recurrent Laryngeal Nerve Damage
This injury results in paralyzed cords and aphonia.
Each paralyzed cord assumes an intermediate position (midway between abduction and adduction).
The cords can flop together causing airway obstruction during inspiration which requires immediate intubation.
The trachea begins ____.
beneath the cricoid cartilage and extends to the carina, the point at which the right and left mainstem bronchi divide.
How many cm above the carina should an ETT be placed?
5-7 cm
The ETT is more likely to advance in the ___.
right bronchus than the left bronchus
Anteriorly, the trachea consists of ____.
cartilaginous rings; posteriorly, the trachea is membranous.
Components of GA airway management
- Preanesthetic airway assessment
- Preparation and equipment check
- Patient positioning
- Preoxygenation (denitrogenation)
- Bag and mask ventilation
- Intubation or placement of a laryngeal mask airway (if indicated)
- Confirmation of proper tube or airway placement
- Extubation
Standard Preanesthetic Assessment includes
- Mouth opening: an incisor distance of 3 cm or greater is desirable in an adult.
- Thyromental distance: This is the distance between the mentum (chin) and the superior thyroid notch. A distance greater than 3 fingerbreadths is desirable.
- Neck circumference: A neck circumference of greater than 17 inches is associated with difficulties in visualization of the glottic opening.
- Prominent overbite, neck ROM, shape of palate
- Mallampati classification: a frequently performed test that examines the size of the tongue in relation to the oral cavity. The more the tongue obstructs the view of the pharyngeal structures, the more difficult intubation may be.
Mallampati classification
Class I - The entire palatal arch, including the bilateral faucial pillars, is visible down to the bases of the pillars.
Class II - The upper part of the faucial pillars and most of the uvula are visible.
Class III - Only the soft and hard palates are visible.
Class IV - Only the hard palate is visible.
Indications of Difficult Bag Mask Ventilation
- Mask seal impeded by beards, anatomy, or nasogastric tube
- Obstruction of upper or lower airway
- Obesity with redundant upper airway soft tissue
- Age greater than 55 r/t loss of upper airway elasticity
- Absence of teeth
- Decrease lung elasticity
- Obstructive sleep apnea or snoring
Pneumonic = “BONES” Beard, obstruction, no teeth, elderly, sleep apnea
Indications of Difficulty with Direct and Video Laryngoscopy with Tracheal Intubation
- Evaluate the 3-3-2 rule
- Mallampati score (classes III and IV indicating increased difficulty)
- Obstruction of the upper airway
- Obesity with increased neck circumference and redundant soft tissue
- Scarring, radiation, or masses on the neck
- Neck mobility that is impaired by disease of immobilization
“LEMON”
Look externally face shape, obesity, face and neck pathology
Evaluate 3 3 2
Mallampati
Obstruction
Neck mobility
Indication of Difficulty With Supraglottic Airway Device Placement and Ventilation
Restricted mouth opening
Obstruction of the upper airway
Distortion of airway anatomy preventing an adequate seal
Stiff lungs (e.g., increases in airway resistance or decreases in pulmonary compliance)
Pneumonic = RODS
Indication of Difficulty With Cricothyrotomy Airway Placement
- Distortion of neck anatomy (e.g., hematoma, infection, abscess, tumor, scarring from radiation)
- Obesity or a short neck limiting cricothyroid identification
- Trauma in or around the cricothyroid area
- Impediments causing limited access to the neck (e.g., halo device, fixed flexion abnormality)
- Surgery causing limited access to anatomic landmarks
Pneumonic = SHORT (surgery, hematoma, obesity, radiation, tumor/trauma)
What equipment should be routinely available for airway management?
- An oxygen source
- Capability to ventilate with bag and mask
- Laryngoscopes (direct and video)
- Several ETTs of different sizes with available stylets and bougies
- Other (not ETT) airway devices (eg, oral, nasal, supraglottic airways)
- Suction
- Pulse oximetry and CO2 detection
- Stethoscope
- Tape
- Blood pressure and electrocardiography (ECG) monitors
- Intravenous access
Preoxygenation before anesthetic induction and tracheal intubation
designed to increase the body oxygen stores and thereby delay the onset of arterial hemoglobin desaturation during apnea.
the need for preoxygenation is desirable in all patients
routine preoxygenation before the tracheal extubation has also been recommended
End points of maximal preoxygenation (efficacy) would be ____.
an end-tidal oxygen concentration of 90%
The sniffing position can help ____.
align the oral, laryngeal and pharyngeal axises
Patients with morbid obesity may have ____.
redundant tissue of the back and require a ramp to align these axises
Which patients must remain in a neutral position?
Those with unstable cervical spines and/or in c-collars
Which scenarios would NOT include bag mask ventilation?
patients undergoing rapid sequence intubation or elective awake intubation
Effective mask ventilation requires both ____.
1) a sealed mask fit, and 2) a patent airway; and will result in chest rise, end-tidal CO2 detected condensation in the clear mask
The recurrent laryngeal nerve (RLN) innervates all of the muscles of the airway EXCEPT ____.
The cricothyroid- which is innervated by the superior laryngeal nerve (SLN)
If you’re having trouble ventilating, ask yourself: ___?
- Do I have a good mask seal?
- Do I have a patent airway?
Face straps can be used to improve mask seal but can cause ____.
trigeminal and/or facial nerve injury if used for a prolonged period
What would be a sign of poor mask seal?
A deflated reservoir bag, despite the adjustable pressure-limiting valve being closed, suggests a poor mask seal.
Use your little finger to bring the mandible towards the face mask
What would be a sign of an obstructed airway or obstructed tubing?
The generation of high breathing circuit pressures with minimal chest movement and breath sounds.
Oral pharyngeal airways can help improve the patency of many airways when the correct size is used
One-handed face mask technique
The mask is held with the left hand and the right hand is used to generate positive-pressure ventilation by squeezing the reservoir bag
- The thumb and index finger apply downward pressure
- The middle and ring finger grasp the mandible and extend the atlantooccipital joint
- The little finger ⭐️ is placed under the angle of the jaw and used to thrust the jaw anteriorly
Two-handed face mask technique
This technique can be used if there is difficulty obtaining an adequate mask seal and/or a patent airway
The anesthesia professional uses two hands to provide adequate jaw thrust and to create a mask seal
The assisting clinician ventilates by squeezing the reservoir bag
Basic facts about an oral airway
- Holds tongue down
- Objective is to keep the tongue from blocking the airway
- Should reach the base of tongue but not beyond
- May stimulate airway reflexes
Supraglottic airway devices
When do we use them and what do they do?
Supraglottic airway devices (SADs) are used with both spontaneously breathing and ventilated patients during anesthesia. Also, they are used to aid endotracheal intubation when both BMV and endotracheal intubation have failed.
SADs consist of a tube that is connected to a respiratory circuit or breathing bag, directing airflow to the glottis, trachea, and lungs
Examples of supraglottic devices include ____.
the esophageal-tracheal combitube, king laryngeal tube, and the commonly used, laryngeal mask airway (LMA)
What is an LMA? How is it inserted?
A laryngeal mask airway (LMA) consists of a wide-bore tube whose proximal end connects to a breathing circuit and whose distal end is attached to an elliptical cuff that can be inflated through a pilot tube
The deflated cuff is lubricated and inserted blindly into the hypopharynx so that, once inflated, the cuff forms a low-pressure seal around the entrance to the larynx.
Considerations for an LMA
This requires anesthetic depth and muscle relaxation slightly greater than that required for the insertion of an oral airway.
The LMA is not a secure airway and does not protect against gastric regurgitation
To avoid insufflating the stomach, positive pressure ventilation should not be administered through an LMA at pressures higher than 20 mmHg
10 steps of an LMA insertion
- Choose the appropriate size and check for leaks before insertion.
- The leading edge of the deflated cuff should be wrinkle free and facing away from the aperture.
- Lubricate only the back side of the cuff.
- Ensure adequate anesthesia before attempting insertion.
- Place patient’s head in sniffing position .
- Use your index finger to guide the cuff along the hard palate and down into the hypopharynx until an increased resistance is felt. The longitudinal black line should always be pointing directly cephalad (ie, facing the patient’s upper lip).
- Inflate with the correct amount of air.
- Ensure adequate anesthetic depth during patient positioning.
- Obstruction after insertion is usually due to a down-folded epiglottis or transient laryngospasm.
- Avoid pharyngeal suction, cuff deflation, or laryngeal mask removal until the patient is awake (eg, opening mouth on command).
LMA Sizes and Cuff volume
Advantages and disadvantages of the laryngeal mask airway compared with face mask ventilation or tracheal intubation
Endotracheal Intubation (use and size selection)
ETTs are often used to for general anesthesia and to facilitate ventilation
A stylet can be used prior to insertion to adjust the shape of the ETT
The ETT end is beveled to aid visualization during intubation
ETT size selection is based on maximizing airflow and minimizing airway trauma
- Typically, adult men receive a 7.5 (mm) ETT and women 7.0 (mm) ETT
- Both tubes are 24 cm long
ETT cuff inflation system consisting of ____.
a valve, pilot balloon, inflating tube, and cuff
The valve prevents air loss after cuff inflation.
The pilot balloon provides a gross indication of cuff inflation
a tracheal seal, ETT cuffs permit positive-pressure ventilation and reduce the likelihood of aspiration.
What are the two types of ETT cuffs?
1) High-pressure cuffs
2) Low-pressure cuffs
* Other types of tubes include armored tubes, double lumen tubes, laser safe tubes and preformed curve tubes
Full term infant (ETT internal diameter & cut length)
Internal Diamter = 3.5 mm
Cut length = 12 cm
Child
Internal Diamter = 4 +(Age divided by 4) in mm
Cut length = 4 +(Age divided by 2) in cm
Adult female (ETT internal diameter & cut length)
Internal Diamter = 7.0-7.5 mm
Cut length = 24 cm
Adult male (ETT internal diameter & cut length)
Internal Diamter = 7.5-9.0 mm
Cut length = 24 cm
General Info on Laryngoscopes
A laryngoscope is used in anesthesia to facilitate tracheal intubation with a direct view of the vocal cords.
The handle contains batteries which power a light on the laryngoscope blade
Confirm the batteries and light are working when you are preparing for the case
There are unique laryngescopes that are MRI compatible
What are the two most common laryngoscopes?
The Macintosh and Miller are the most popular laryscope blades
The Macintosh’s (Mac) curved blade is placed in the patient’s vallecula
The Miller’s straight blade lifts the patient’s epiglottis
Layryngoscope blade selection depends on provider’s preference and patient anatomy
Video Layngeoscopes (general information)
a video chip at the end of the blade to provide a view of the vocal cords without aligning the oral, pharyngeal and laryngeal axises
helpful for anesthesia trainees or patient’s with difficult airways as they improve visualization of the vocal cords **Note: improved view does not always translate to improved placement of ETT into the trachea
Examples of video laryngoscopes include the Glidescope, McGrath laryngoscope, CMAC, and the Airtraq
What is a flexible fiberoptic scope?
A flexible fiberoptic scope (FOS) has coated glass fibers that transmits light and images and can provide a high-resolution image of the vocal cords.
FOS have an aspiration channel for suctioning, oxygen or instillation of local anesthetics (for an awake intubation)
FOS have dials to help maneuver the scopes tip through the vocal cords
When can I use a flexible fiberoptic scope (FOS)?
Patient types - advantageous in patients with unstable cervical spines, poor mouth opening and/or upper airways anomalies
Induction types – asleep or awake intubations
Tracheal tube types – oral and nasal tracheal tubes
Anesthesia Indication for Tracheal Intubation
High risk of aspiration of blood (e.g., head and neck trauma, bleeding into respiratory tract) or gastric contents (e.g., severe gastroesophageal reflux disease, inadequate gastric emptying, gastrointestinal obstruction)
Predicted difficult airway
Intraoperative patient positioning that may impede access to the airway (e.g., prone, lateral decubitus)
Ineffective oxygenation or ventilation with supralaryngeal airway (e.g., mask ventilation, laryngeal mask airway)
Surgical Indications for Tracheal Intubation
Airway access shared with surgeon (e.g., otolaryngologic and head-neck surgery)
Surgery requiring paralysis by neuromuscular blocking medications (e.g., intraabdominal surgery)
Surgical procedures affecting ventilation and perfusion (e.g., cardiothoracic surgery)
Prolonged surgical time
Medical Indications for Tracheal Intubation
Inadequate airway protection or suppressed airway reflexes (e.g., Glasgow coma scale less than 10)
Ineffective oxygenation or ventilation (e.g., noninvasive positive pressure respiratory assist device, mask ventilation, laryngeal mask airway)
Critical illness (e.g., inadequate respiratory function, acute respiratory distress syndrome, sepsis)
Controlled management of arterial carbon dioxide content (e.g., prevention of hypercapnea for increased intracranial pressure)
Preparation for Direct Laryngoscopy
- Checking equipment and properly positioning the patient
- The tube’s cuff can be tested by inflating the cuff using a syringe
- The ETT’s stylet should be bent like a hocky stick to facilitate intubation of an anterior larynx
- The desired blade is locked onto the laryngoscope handle, and bulb function is tested
- An extra handle, blade, ETT (one size smaller than the anticipated optimal size), stylet, and intubating bougie should be immediately available.
- A functioning suction unit is needed to clear the airway in case of unexpected secretions, blood, or emesis.
- To avoid back strain, raise the OR bed so the patient’s head is at waist level
- Preoxygenate the patient to increase apnea time without desaturation
Steps of Orotracheal Intubation
1) The mouth is scissored open widely by placing the thumb and middle finger of the right hand on the patient’s right molars
2) The laryngoscope is placed in the left hand and gently introduced on the right side of the patient’s mouth
3) With the laryngoscope blade, the tongue is swept to the left side of the mouth
4) The tip of a curved blade is usually inserted into the vallecula, and the straight blade tip covers the epiglottis.
5) The handle is raised up and away from the patient *Avoid 1) pinching the lip between the teeth and blade, and 2) rocking back on the upper teeth
6) External Backward, upward, rightward pressure (BURP) can be helpful to bring the vocal cords into view
7) The ETT is held in the right hand and the tip is placed between the vocal cords
8) The ETT stylet is removed, and the tube is advanced, so the cuff is beyond the vocal cords & the laryngoscope blade is gently removed
9) The ETT cuff is inflated with an appropriate volume.
10) The chest and epigastrium are immediately auscultated, and three appropriate capnographic tracings (the definitive test) are monitored to ensure intratracheal location
Examples of adjustments to make after an unsuccessful intubation
repositioning the patient, selecting a different blade, using an indirect laryngoscope and/or requesting the assistance of another anesthesia provider
What must happen if the patient is also difficult to ventilate with a mask?
alternative forms of airway management (eg, second-generation supraglottic airway devices, jet ventilation via percutaneous tracheal catheter, cricothyrotomy, tracheostomy) must be immediately pursued.
What questions should you ask with a difficult airway?
- Is airway management necessary?
- Will DL or TI be difficult?
- Can a supralaryngeal ventilation be used?
- Has the risk for aspiration been minimized, or is the stomach empty?
- In the event of airway failure, will the patient tolerate an apneic period?
When is a nasal intubation indicated?
for ENT procedures and/or difficult airways
Steps involved in nasal intubation
The nares are prepared with phenylephrine nasal spray to promote vasoconstriction and mitigate bleeding
Nasal tubes are selected based on the patient’s height. Nasal tubes are placed in warm sterile water to make more malleable during placement
Once asleep, the nares can be dilated with nasal trumpets
Placement of a nasal tube can be facilitated with a FOS scope or with McGill forceps
The cuff of nasal tubes can get torn on nasal turbninates during placement
What are the different surgical airway techniques?
surgical cricothyrotomy, catheter or needle cricothyrotomy, transtracheal catheter with jet ventilation, and retrograde intubation.
If a surgical cricothyrotomy is not available, what would happen next?
a 16- or 14-gauge intravenous cannula is attached to a syringe and passed through the cricothyroid membrane toward the carina. Air is aspirated and the catheter is secured.
If a jet ventilation system is not be available, what next?
a 3-mL syringe can be attached to the catheter and the syringe plunger removed. A 7.0-mm internal diameter ETT connector can be inserted into the syringe and attached to a breathing circuit or an AMBU bag. Allow ample time for exhalation to avoid barotrauma.
This is a temporary bridge to surgical airway.
Complications after a tracheal intubation
Damage to airway anatomy
Hypoxia
Aspiration
Esophageal intubation
Complications after a tracheal extubation
Residual Neuromuscular Blockade
Laryngospasm
Global Criteria for Extubation
- Acceptable hemodynamic status
- Normothermia
- Ability to maintain patent airway
- Adequate muscular strength
- Acceptable metabolic indicators
- Acceptable hematologic indicators
- Adequate analgesia for optimal respiratory effort
Respiratory Criteria for Extubation
Adequate respiratory mechanics
- Vital capacity greater than 15 mL/kg
- Maximal negative inspiratory force greater than −20 cm H2O
- Adequate tidal volume of at least 4–5 mL/kg
Ability to maintain adequate oxygenation (with Fio2 less than 50%)
- SpO2 greater than 90 % & PaO2 greater than 60 mm Hg
Ability to maintain adequate alveolar ventilation
- PaCO2 less than 50 mm Hg
- Acceptable spontaneous respiratory rate (breaths/minute)
Treatment of Laryngospasm
- Remove stimulus (e.g., suction the pharyngeal space)
- Administration of 100% oxygen
- Provide an open and clear airway (e.g., placement of an oral airway)
- Perform a jaw thrust (e.g., Larson maneuver or pressure on the laryngospasm notch)
- Apply positive-pressure ventilation (e.g., 10–30 cm H2O pressure–beware of gastric insufflation)
- Consider deepening the anesthesia with propofol (e.g., 0.5 mg/kg IV)
- Administer succinylcholine (e.g., 0.2–2 mg/kg IV or 4–5 mg/kg IM)
Sphincter Function is controlled by what muscles?
Aryepiglottic & Interarytenoid
Primary outcome with muscle contraction of Aryepiglottic = closes laryngeal vestibule
Primary outcome with muscle contraction of Interarytenoid = closes posterior commissure of glottis
Which muscles adduct the vocal cords?
Thyroarytenoid
Lateral cricoarytenoid
(closes glottis)
Which muscle abducts the vocal cords?
Posterior cricoarytenoid
(widens glottis)
Which muscles adjust their length (tension) of the vocal ligaments?
Cricothyroid- elongates (tenses)
Vocalis- shortens (relaxes)
Thyroarytenoid- shortens (relaxes)
High-pressure ETT cuffs are associated with what?
more ischemic damage to the tracheal mucosa and are less suitable for intubations of long duration.
Low-pressure ETT cuffs may ____.
may increase the likelihood of sore throat (larger mucosal contact area), aspiration, spontaneous extubation, and difficult insertion
Infant LMA size, weight and cuff volume
size 1
weight <6.5kg
cuff volume = 2-4cc
child LMA size weight and volume
size 2 or 2.5
2 = 6.5-20kg, 10cc
2.5 = 20-30kg, 15cc
small adult LMA size
size 3
30-70kg
20cc
adult LMA sizes
4 and 5
4 = 70kg, 30cc
5 = >70kg, 30cc
LMA vs Bag Mask pros and cons
Advantages: hands free, better seal with beards, better for ENT, easier to maintain airway, protects against secretions, less facial nerve and eye trauma, less OR pollution
Disadvantages: more invasive, risk of airway trauma, takes skill, need deeper anesthesia, need TMJ mobility, N2O diffusion into the cuff, and multiple contraindications
LMA vs ETT pros and cons
Advantages: less invasive, good with difficult intubations, less tooth and laryngeal trauma, less laryngospasm and bronchospasm, no NMBs or neck mobility, no risk of esophageal intubation
Disadvantages: r/o aspiration and GI distention, less safe with positions like jackknife, limits max PPV (20mmHG), less secure airway, r/o gas leak and pollution
DAS: Difficult Airway Algorithm
Plan A
Maximize success of tracheal intubation on the 1st attempt by prepping, preoxygenate, and positioning.
limit laryngoscopy to 3 attempts total
DAS: Difficult Airway Algorithm
Plan B
Maintain O2 with SAD/LMA
can use video or fiberoptic guided TI > blind/bougie/through SADs due to risk of trauma
Max 3 attempts
DAS: Difficult Airway Algorithm
Plan C
Facemask to oxygenate
IF POSSIBLE → awaken patient or provide complete paralysis
DAS: Difficult Airway Algorithm
Plan D
CANNOT INTUBATE/VENTILATE → surgical airway.
cricothyrotomy - with scalpel
cont to oxygenate the pt with facemask/SAD/nasal cannula.
