Week 13 - Advanced Airway Flashcards
What is an unexpected failed airway?
Same thing as unanticipated difficult airway –> Although pre-operative airway assessments preformed didn’t indicate the patient as having a difficult airway, they do.
What two things are generally the common causes of unanticipated difficult airways?
- Enlarged lymphoid tissue at the base of the tongue
- Lingual tonsil hyperplasia –> Some indicators include sore throat, dysphagia, globus sensation, snoring, palpation of lump in the throat, and OSA
Experiencing difficulty with either face mask ventilation, laryngoscopy, intubation, or all of these terms the patient as what?
Difficult airway
What are the 4 strategies of airway management?
- Bag mask ventilation
- Placement of a SAD (LMA)
- ETT into the trachea
- Cricothyrotomy
What are indicators of a potential difficult airway?
Anatomic (Mallampati III or IV)
Pathophysiologic (laryngeal mass, neck hematoma)
Trauma (face/neck)
Physiologic (servere hypoxia or hypotension, acidosis)
What are some indications of a difficult face mask ventilation seal/oxygenation?
Gas flow leaks –> increasing the use of the O2 flush, poor chest rise, absent or inadequate breaths, gastric air entry, poor EtCO2 and altered waveform, O2 saturations less than 92%, necessity of oral/nasal airways or two handed mask ventilation
What are some indications for tracheal intubation?
Aspiration risk, NMBA used, patient positioning (prone, lateral decubitus)…
What is considered a difficult tracheal intubation on the Cormack & Lehane grading scale?
Inability to visualize a portion of the vocal cords (Cormack and Lehane III or IV)
What is considered a difficult invasive airway placement (cricothryotomy)?
Bleeding at insertion site, inability to identify correct anatomic structures, and trouble accessing the cricothyroid membrane and puncturing the trachea.
Major complications associated with airway management?
1:22,00 –> Brain damage, emergency surgical airway placement, and unanticipated ICU admission
1:180,000 –> Death
Common causes of SAD failure
Inadequate seal from improper placement, surgical table rotation, poor dentition, male gender, and increased BMI.
What patient population are placed at the highest risk of difficult intubation/ventilation?
Patients with neck or mediastinal pathology, previous surgery, or radiation.
Where are difficult airways encountered more frequently?
Outside the OR –> 30 to 60 times more common in the ED or ICU because these providers aren’t AIRWAY EXPERTS
What 5 questions need to be considered which are part of the airway approach algorithm?
- Is airway management necessary?
- Is DL or VL and TI anticipated to be difficult?
- Can a SAD be used or deemed potentially difficult?
- Risk of aspiration?
- Patient at risk for rapid desaturation?
If all questions are answered yes –> Proceed, airway is deemed manageable
If any question is answered no –> Abandon airway management and proceed with an alternative plan (MAC)
What are the two most commonly used airway algorithms?
ASA and DAS –> ASA is cited and used more.
Should airway algorithms always be used?
No, dependent of the patient.
These ARE NOT a replacement for sound clinical judgement and implementation of interventions you deem necessary, only a guide.
Simplified ASA airway algorithm
- Tracheal intubation via DL, if failed –> attempt calling for help, awakening the patient, and returning to spontaneous ventilation from this point forward –> 2
- Face mask ventilation, if failed –> 3
- SAD ventilation, if failed –> 4
- Intubation by special means (different blades, LMA with intubation conduit, fiber optic…), if failed –> 5
- Emergency airway
What are the 4 endpoints in the ASA airway management algorithm?
- Awake or asleep intubation
- Face mask (1st) or LMA ventilation (2nd)
- Approach to intubation by special means (different blades, LMA with intubation conduit, fiber optic…)
- Surgical and non surgical emergency airway access
What should be done if you are suspicious of airway trouble?
Awake intubation
When making intubation choices, you should ___________
Do what you do best
If you get into trouble but can still ventilate the patient, what should be the next step?
Awaken the patient.
What is the key component in the DAS algorithm?
Communication with the OR team and verbalizing failure and moving onto a new step.
According to the DAS algorithm, you should maximize the patient for intubation success on what attempt?
1st! –> includes preparation, positioning, and pre oxygenating. Limit attempts to 3 tries before moving onto the next step.
According to the DAS algorithm, what is plan B?
Insertion of the supraglottic airway –> Use a 2nd generation because of its benefits (high seal pressures, first time placements, can be used as a conduit)
Placement should be limited to three attempts
According to the DAS algorithm, what should be done in plan C after face mask ventilation fails?
Provide complete paralysis and move to plan D.
According to the DAS algorithm, what should be done in plan C if face mask ventilation is adequate?
Awaken the patient
Why are laryngoscope attempts limited to 3 attempts or less?
To prevent excessive airway trauma.
When you have a patient with an anticipated difficult airway, what should be done during the first attempt at intubation?
This should be your best attempt with proper patient position, pre oxygenation and preparation.
When you have a patient with an unanticipated difficult airway, what should be done during the first attempt at intubation?
This is used as the awareness look or view, scoping out the airway. The second attempt should be the “best” attempt with the most experienced provider.
What should be included in a difficult airway cart?
Each facility should have one! –> No standardized list but developed by each department. Some good things to have are –>
Standard laryngoscope, intubation supplies by alternative means, tube position control, equipment to anesthetize the airway, and may or may not include video/FOB laryngoscopy
Awake intubation generally calls for what 2 intubating techniques?
Video laryngoscopy to facilitate TI or determine a difficult airway AND fiberoptic endoscope with preloaded ETT
What are some benefits to awake intubation?
Patient maintains their own ventilation and preserves their pharyngeal and laryngeal muscle tone improving the size of the pharynx and decreased risk of aspiration
Absolute contraindications to awake intubation?
None, if it is your safest option then you do it.
Sedative medications may be appropriate for awake intubations, when do they become problematic?
When the patient is over sedated. This takes away all the benefits of awake intubation. Causes respiratory depression and relaxation of muscle tone which can lead to total obstruction of the airway.
(DEXMED, propofol, etomidate, midazolam, fentanyl…)
Can generally do without these and just use local.
For an awake intubation with a patient who has topical anesthetic allergies, what medication should be used?
Dexmedetomidine
How would you define “awake” in an awake intubation?
Patient is cooperative and ventilating spontaneously.
How might awake laryngoscopy to determine a difficult airway be useful?
Allows you to decide
1. Proceed with video or FIS while the patient is awake
2. Proceed with anesthesia induction and NMBA to optimize airway conditions
What is something that can be done preoperatively to determine airway difficulty?
Preoperative endoscopic airway exam using minimal sedation and topical prior to entering the OR
What are some situations that awake intubation would be necessary?
Patients with previous airway difficulty, unstable neck fractures, halo devices, small or limited oral openings, upper airway mass, facial or neck trauma, physiologic compromise, and in the critical care setting.
What must be done for maximal patient cooperation during an awake intubation?
Procedure must be clearly explained and consent must be obtained.
What antisialagogue can be given in an awake intubation? How does this help with intubation?
Atropine –> 0.5 - 1 mg IV
Glycopyrolate –> 0.2 - 0.4 mg IV or IM
Give 20 minutes prior!
These will decrease sections which will maximize laryngeal view
True or False
Antisialagogue can enhance topical anesthetics penetration?
True, these decrease secretions allowing more of the anesthetic to penetrate the mucosa.
How is the risk of aspiration affected in an awake intubation?
Decreased, patient will maintain more esophageal sphincter tone while awake
Medications to decrease stomach acid production and promote gastric emptying should still be considered (H2 blockers)
What precautions should be taken prior to a nasal intubation?
Give a vasoconstrictor such as Afrin (0.05%) or Phenylephrine 2-3 minutes prior to application of local anesthetic to decrease risk of mucosal damage and hemorrhage.
What is the most commonly used local anesthetic?
Lidocaine 2% –> Peak levels are highest after 30 minutes
Others used are cocaine (4%), benzocaine (20%), and tetracaine
Maximum safe dose of lidocaine shouldn’t exceed _________________
4-5 mg per kg IV –> Always assess for signs and symptoms of toxicity!
Methods of airway blockade via medications
Topical, infiltration or both
What three nerves/branches are we blocking when preforming an airway all day block?
Trigeminal, glossopharyngeal, and the vagus nerves.
What nerve provides sensory innervation to the lateral wall and nasal septum? What branches of this nerve?
Trigeminal –> Ophthalmic and maxillary branches
What nerve provides sensory innervation for the anterior 2/3 of the tongue?
Lingual nerve –> This stems from the trigeminal nerve which branches into the mandibular nerve and then into the lingual.
Where does the glossopharyngeal nerve innervate?
Posterior 1/3 of tongue, upper pharynx, and the inner surface of the tympanic membrane via its lingual branches.
What does the vagus nerve innervate in the mouth/airway?
Hypopharynx, larynx, and trachea via the SLN and RLN
What does the internal SLN innervate specifically?
Sensation above the vocal cords
What does the RLN innervate?
Subglottic area (below the cords)
What nerve branches are blocked via topical anesthetic to the nasal septum and lateral wall?
Anterior ethmoidal, nasopalatine, and sphenopalatine nerves stemming from the ophthalmic and maxillary branches of the trigeminal nerve
How can the nasal septum and lateral walls be anesthetized using topical?
Viscous 4% lidocaine can be sprayed down each nostril
Can use a CTA and slowly work lidocaine into each nare
How can the nasal and oral cavities (nasopharynx and oropharynx) be anesthetized via topical methods?
Adding 4-10 mL of 4% lidocaine and 1 mL of 1% phenylephrine to a nebulizer –> This takes 10-20 minutes, may need additional topical if doing awake intubation!
This method is also used during anesthetization of the subglottic tissue
What is atomization?
This is like nebulization but it produces much larger droplets, resulting in more medication coating the upper airway mucosa and producing a denser block.
Should be done via 5-8 big breaths through nose/mouth
What is a good concoction for atomization of the oral and pharyngeal cavities?
10 mL or less of 4% lidocaine and a small amount of 5% lidocaine paste.
What is the purpose of anesthetizing the mouth and oropharynx prior to intubations?
Decreases the cough and gag reflexes associated with awake intubations.
Why should you be careful when anesthetizing the tongue and mouth with Benzocaine 20% spray?
Because the toxic dose of this drug is 100 mg or more. With just a half of a second spray, this delivers 0.15 mL or 30 mg of medication, a third of the toxic level
What common side effect has been reported with the use of benzocaine topical spray?
Methemoglobinemia (affects how Hgb delivers oxygen throughout your body) –> Treatment includes Methylene blue
What is a good method for anesthetizing the posterior tongue, vallecula, and anterior epiglottis?
Lidocaine lollipop –> Coat a tongue blade with 5% lidocaine paste and apply to the back of the tongue –> This allows the paste to melt and coat the base of the tongue, vallecula, anterior epiglottis, and sometimes even the vocal cords.
Should allow 1-2 minutes for this paste to liquify and coat the tongue
What is a good method for anesthetizing the posterior tongue, vallecula, and anterior epiglottis if lidocaine paste isn’t available/lidocaine lollipop method?
Atomization with a 4% lidocaine solution
Best method for anesthetizing the vocal cord?
Directly spraying them –> Can be done by depositing local down the ET tube when in close proximity of the vocal cords and instructing the patient to take a deep breath.
This causes the patient to cough which sprays the vocal cords.
How can you anesthetize the vocal cords via atomization?
While viewing the vocal cords with a flexible intubating endoscope or video laryngoscope, you can visually deposit 4% lidocaine onto the cords.
If using fiberoptic scope –> place an 18 gauge epidural catheter through the suction channel and inject topical onto cords.
Step by step process to preforming a glossopharyngeal nerve block. 5 steps.
- Anesthetize the tongue with topical, have the patient open their mouth and protrude the tongue forward.
- Displace tongue to opposite side of where you will inject with a tongue blade
- Insert a 23-25 gauge spinal needle approximately 0.25-0.5 cm into the lingual gutter (where lingual gutter meets palatoglossal arch)
- Aspirate –> If air you are too deep and needle should be withdrawn until no air is aspirated, if blood you are too lateral and should reinsert more medial to avoid possible intra carotid injection (Injecting here can cause seizures)
- Once correct placement, inject 1-2 mL of 2% lidocaine. Repeat this process for the other side
Swish and gargle/spit method for topical anesthetic?
Use 2-4% lidocaine, have patient swish and gargle this for 2 minutes –> then spit out
Step by step process to preforming a superior laryngeal nerve block. 6 steps
- Locate the greater cornu of the hyoid bone (beneath the angle of the mandible and can be palpated on either side of the neck as a rounded structure)
- Displace hyoid bone towards the side you are injecting to stabilize the bone and to facilitate identification of structures.
- Insert needle perpendicular to the skin and advance to contact the inferior boarder of the greater cornu
- Needle is then “walked off” the caudal edge of the hyoid bone where it hits the thyrohyoid membrane –> Needle may feel resistance and bounce on this membrane
- Aspirate and ensure no blood or air –> air = too deep and needs to be withdrawn until no air. blood = needs to be withdrawn and reinserted
- Inject 1 mL (2% lidocaine) above the thyrohyoid membrane, then pierce membrane and inject 2 mL. Repeat on other side
Step by step process to preforming a transtracheal nerve block.
- Palpate the cricothyroid membrane
- Insert 22-24 gauge needle puncturing the membrane in a caudal direction (prevents potential vocal cord injury) while aspirating continuously
- When you start seeing air bubbles, you know you are in the trachea –> Instruct the patient to take a deep breath then inject 3-5 mL of 2% lidocaine
- This will cause the patient to cough spraying the vocal cords, make sure to stabilize needle! Use of a softer angio catheter may decrease trauma
What is the purpose of cricoid pressure?
Posterior displacement of the cricoid cartilage against the cervical vertebrae preventing regurgitation of gastric contents by compressing the esophagus during the induction of general anesthesia –> Should be done with the patients head elevated 20 degrees.
How much pressure should be applied to the cricoid during cricoid pressure?
10-20 N (1-2 kg of force) prior to loss of consciousness
30-40 N (3-4 kg of force) after loss of consciousness
This is equivalent to applying firm pressure to the bridge of the nose that would cause discomfort
Drawbacks to cricoid pressure?
Been questioned of its efficacy –>
Studies only conducted on cadavers, can interfere with the visualization of the airway on laryngoscopy, and may even INDUCE relaxation of the lower esophageal sphincter!
MRI found that in 50% of patients their esophagus is lateral to the cricoid ring, not directly posterior as suggested
What should be done if you are holding cricoid pressure and your patient begins to vomit?
Should release pressure immediately! This can actually cause a buildup of pressure if you don’t release, leading to a perforated esophagus
What are some contraindications to cricoid pressure?
Cervical spine injury and RSI (decreases upper and lower esophageal tone)
What are supraglottic airway devices? (SAD)
Devices which provide ventilation above the glottic opening –> LMA, face mask
What are some common retroglottic or infraglottic airway devices (still considered SADs because ventilation is provided superiorly to the glottic opening)?
Combitube, King LT airway –> These devices pass behind the larynx and enter the upper esophagus.
No mask that covers the laryngeal opening but two cuffs –> distal balloon sealing the esophagus.
NOT SUITABLE AS A CONDUIT
What are the 3 reasons to use a supraglottic airway device?
- Rescue ventilation after difficult mask ventilation or failed tracheal intubation
- A primary means of ventilation or alternative to ETT if appropriate
- As a conduit to facilitate ET tube intubation
In daily clinical use, the LMA can be used in place of __________ during general anesthesia, if apporpriate.
Bag mask ventilation
How are LMA’s sized?
Weight based in kg
What size LMA would a 80 kg patient get?
Size 5 –> 70 - 100 kg
The PLMA (Proseal) offers a better airway seal than the LMA classic allowing for ______________
increased peak ventilation pressures (up to 28-30 cm H2O)
What is the disposable version of the PLMA (Proseal)
LMA supreme (curved fixed design) –> Allows less peak ventilation pressures of 26-28 cm H2O, compared to PLMA of 28-30 cm of H2O but first time insertion rates are higher with the LMA supreme over the PLMA
What is an i-gel SAD?
Second generation SAD, no inflatable cuff –> just medical grade thermoplastic elastomer. Can also be used as a conduit for ETT intubation.
Associated with high seal pressures, lower incidence of sore throat, and relative ease of insertion
What is the most well known and used intubating LMA?
LMA Fastrach –> Allows continuous ventilation until TI is accomplished
After successful intubation when using the LMA Fastrach, what should occur next?
Remove the rigid LMA Fastrach to avoid sustained pressure on the hypopharyngeal tissue
What intubating SAD can be used in pedatrics?
air-Q –> LMA Fastrach doesn’t provide pediatric sizes
What is the Trachlite lighted stylet?
A lighted stylet that uses transillumination of the neck to accomplish ET intubation
- Blind approach
- Less stimulation than other methods and can be used when awake
- LESS affected by anterior airway
When using the Trachlite, what drawbacks are present when intubating extremely thin patients?
False positive –> The glow will look brighter, making you think you could have correct placement but are in the esophagus.
What is the Eschmann Stylet (Gum eleastic bougie)?
Blind intubation technique –> Used when the glottic opening is difficult to visualize (Grade IIb or III)
15 Fr, 60 cm long with a 40 degree bent tip
What can be an indication that the Eschmann Stylet (Gum eleastic bougie) is in the trachea?
Can feel the stylet bounce along the tracheal rings –> May not always be felt though.
Once this is in the trachea, an ETT is slid over the stylet and guided into the trachea.
What is an airway exchange catheter (AEC)?
Very long tube that can be used for ET tube change, or placed prior to extubation in a difficult airway
Indications for use of the flexible fiberoptic intubating scope (FIS)?
When using the flexible fiberoptic intubating scope (FIS), how should to cord look during the procedure?
Should be kept taut
Common reasons for failed flexible fiberoptic intubating scope (FIS)?
What are some disadvantages to flexible fiberoptic intubating scope (FIS)?
Which cricothyrotomy procedure is reserved as the last resort between the three procedures?
Needle with TTJV –> Evidence of significant failure rates
What risk to the lungs are present with needle cricothyrotomy with TTJV
Barotrauma, the O2 source is plugged directly into pipeline pressure of 50 psi –> regulator is present and should be decreased to 25 psi
After the cricothyroid membrane has been pierced with a needle or trocar device and the wire in threaded into the trachea, what is the next steps for a percutaneous (wire-guided) cricothyrotomy?
What is a surgical cricothyrotomy?
Cutting through the cricothyroid membrane with a scalpel and then placing a cuffed tracheostomy or ETT.
How should the initial incision be preformed in a surgical cricothyrotomy? What do you do next?
Make a horizontal incision first at the top of the cricoithyroid membrane and then rotate scalpel 90 degrees, now –> vertical cut down incision from the thyroid cartilage, moving caudad several centimeters to the cricoid cartilage.
What happens during a surgical cricothyrotomy after the incision has been made to the cricothyroid membrane?
A bougie is advanced into the trachea while the scalpel is still in place
What is the Seldinger technique?
Complications of tracheal extubation?
Standard extubation criteria?
Four things that can be done during extubation in a patient with a difficult airway to aid in re intubation if indicated?
- Extubate over a flexible intubating endoscope
- Extubate followed by the placement of an SAD
- Extubate over an AEC
- Leave ET tube in place until extubation criteria has been met.
