Airway Mgmt Flashcards
What is the recommendation for clear liquids before surgery?
2 hours
Clear liquids help reduce gastric volume and increase gastric pH, lowering the risk of Mendelson syndrome.
What is the recommended time frame for breast milk before surgery?
4 hours
This is part of the guidelines to ensure safety during surgical procedures.
How long before surgery should nonhuman milk, infant formula, or solid food be ingested?
6 hours
This guideline is to minimize risks related to anesthesia.
What may require eight hours or more before surgery?
Ingestion of fried and fatty foods
These types of foods can increase gastric contents and complicate anesthesia.
What syndrome is reduced by ingesting clear liquids two hours before surgery?
Mendelson syndrome
This syndrome is associated with aspiration of gastric contents during anesthesia. Risk factors = gastric pH <2.5 and gastric volume > 25 ml (0.4 mL/kg)
What are predictors of difficult laryngoscopy?
Small mouth opening, prominent overbite/retrognathic jaw, inability to bite upper lip with lower teeth, long incisors, Mallampati class three or four, high arched palate, short thick neck, short thyromental distance, reduced cervical mobility.
What does a Cormack-Lehane grading system class four indicate?
You cannot see the epiglottis or any of the structures. This indicates a difficult airway and is not a predictor of a difficult airway.
How does a lightly anesthetized patient tolerate nasopharyngeal airway compared to oropharyngeal airway?
The lightly anesthetized patient is more tolerant of a nasopharyngeal airway than of an oropharyngeal airway.
An oropharyngeal airway in a lightly anesthetized patient can precipitate laryngospasm.
What are the contraindications to using a nasopharyngeal airway (NPA)?
Contraindications to an NPA include:
• Coagulopathy (risk of epistaxis)
• Basilar skull fracture
• Nasal fracture
• CSF rhinorrhea
• Previous transsphenoidal hypophysectomy
• Previous Caldwell-Luc procedure
What is the LMA-Classic size for patients under 5 kg?
1
What is the LMA-Classic size for patients between 5 kg and 10 kg?
1.5
What is the LMA-Classic size for patients between 10 kg and 20 kg?
2
What is the LMA-Classic size for patients between 20 kg and 30 kg?
2.5
What is the LMA-Classic size for patients between 30 kg and 50 kg?
3
What is the LMA-Classic size for patients between 50 kg and 70 kg?
4
What is the LMA-Classic size for patients between 70 kg and 100 kg?
5
What is the LMA-Classic size for patients over 100 kg?
6
What is the largest ETT that fits for LMA Class Size 1?
3.5
Cuff vol is 4.0.
What is the largest ETT that fits for LMA Class Size 1.5?
4.0
Cuff vol 7.
What is the largest ETT that fits for LMA Class Size 2?
4.5
Cuff vol 10.
What is the largest ETT that fits for LMA Class Size 2.5?
5.0
Cuff vol 14
What is the largest ETT that fits for LMA Class Size 3?
6.0 cuffed
Cuff vol 20
What is the largest ETT that fits for LMA Class Size 4?
6.0 cuffed
Cuff vol 30
What is the largest ETT that fits for LMA Class Size 5?
7.0 cuffed
Cuff vol 40.
What is the largest ETT that fits for LMA Class Size 6?
7.0 cuffed
Largest ETT is 7.0 cuffed.
What are the complications of LMA use?
Nerve injury: recurrent laryngeal, hypoglossal, lingual; Pharyngeal necrosis; Trauma to the uvula; Sore throat
What conditions can increase the risk of complications with LMA?
LMA is too small; Nitrous oxide (if cuff pressure isn’t monitored throughout the procedure); Non-supine positions
What is the only absolute contraindication to cricothyroidotomy?
Young age (age < 10 years)
Children have pliable and mobile laryngeal and cricoid cartilages, making the procedure challenging.
What is the preferred surgical airway technique for children under 10 years?
Tracheostomy
**Footnote
Percutaneous transtracheal ventilation
When is cricothyroidotomy useful?
When facial trauma impairs conventional airway management methods.
Is an unstable cervical spine a contraindication for cricothyroidotomy?
No, as long as cervical spine immobilization is employed.
Does a neck burn injury contraindicate cricothyroidotomy?
No, it can make landmark identification more difficult but is not a contraindication.
What does thyromental distance (TMD) help estimate?
The size of the submandibular space
A TMD less than 6 cm or greater than 9 cm correlates with an increased risk of difficult intubation.
What is the significance of a thyromental distance less than 6 cm?
It correlates with an increased risk of difficult intubation
A TMD greater than 9 cm also indicates increased risk.
What does the mandibular protrusion test (MPT) assess?
The function of the temporomandibular joint
The patient is asked to sublux the jaw during this assessment.
What is a Class 3 MPT indicative of?
Increased difficulty of intubation
The comparison is made between the positions of the lower and upper incisors.
What joint’s mobility is crucial for placing a patient in the sniffing position?
Atlanto-occipital joint
Conditions that impair this mobility include arthritic disease, trauma, and Down syndrome.
Fill in the blank: A TMD greater than _______ cm correlates with an increased risk of difficult intubation.
9
Fill in the blank: The ability to expose the glottic opening during laryngoscopy requires displacing the tongue into the _______ space.
submandibular
True or False: A small or poorly compliant submandibular space can hinder tongue movement necessary for glottis exposure.
True
What conditions that impair AO mobility:
• Degenerative joint disease
• Rheumatic arthritis
• Ankylosing spondylitis
• Trauma
• Surgical fixation
• Klippel-Feil
• Down syndrome
• Diabetes mellitus (joints become less mobile)
What indicates a higher likelihood of airway difficulties according to the 3-3-2 rule?
Airway difficulties are more likely when:
• Inter-incisor gap < 3 finger breaths
• Thyromental distance < 3 finger breaths
• Thyrohyoid < 2 finger breaths
What is the Cormack and Lehane grading system used for?
It helps measure the laryngoscopic view obtained during direct vision laryngoscopy.
What does Grade 1 in the Cormack and Lehane grading system indicate?
Complete or nearly complete view of the glottic opening.
What does Grade 2A in the Cormack and Lehane grading system indicate?
Posterior region of the glottic opening.
What does Grade 2B in the Cormack and Lehane grading system indicate?
Corniculate cartilages and posterior vocal cords (no glottic opening).
What does Grade 3 in the Cormack and Lehane grading system indicate?
Epiglottis only.
What does Grade 4 in the Cormack and Lehane grading system indicate?
Soft palate only.
How does the Cormack and Lehane score relate to intubation difficulty?
Grade 1 & 2A = Easier intubation; Grade 2B & 3 = Harder intubation (consider a bougie); Grade 4 = Requires an alternative approach to intubation.
What are the 5 questions to ask before anesthetizing someone?
- Will I be able to mask ventilate? (BONES)
- Will I be able to intubate? (LEMON)
- Will I be able to place a supraglottic airway? (RODS)
- Will I be able to place an invasive airway? (SHORT)
- How fast must I secure the airway? (2, 4, 6, 8)
What does BONES stand for in airway management?
BONES: beard, obese BMI >26kg, no teeth, elderly >55 yrs, snoring
What does LEMON stand for in airway management?
LEMON: look externally at pathology of neck and head, evaluate 3-3-2, mallapati score, obstruction, neck mobility
What does RODS stand for in airway management?
RODS: restricted mouth opening, obstruction, distorted airway, stiff lungs or c spine
What does SHORT stand for in airway management?
SHORT: surgery, hematoma, obesity, radiation, tumor
What are the time intervals for securing the airway?
2, 4, 6, 8
What congenital condition is associated with a large tongue?
Beckwith syndrome and Trisomy 21 (Down syndrome)
Remember ‘Big Tongue’
What congenital conditions are associated with a small or underdeveloped mandible?
Pierre Robin, Goldenhar, Treacher Collins, Cri du Chat
Remember ‘Please Get That Chin’
What congenital conditions are associated with cervical spine anomalies?
Klippel-Feil, Trisomy 21, Goldenhar
Remember ‘Kids Try Gold’
What is the ‘sniffing position’?
The ‘sniffing position’ consists of cervical flexion and atlanto-occipital extension, aligning the oral, pharyngeal, and laryngeal axes during laryngoscopy.
How does obesity affect laryngoscopy?
In morbidly obese patients lying supine, excess adipose tissue can misalign the oral, pharyngeal, and laryngeal axes.
What is the HELP position?
The HELP position (Head Elevated Laryngoscopy Position) addresses misalignment issues in obese patients.
What is the effect of reverse Trendelenburg position?
Putting the bed in reverse Trendelenburg position unloads the diaphragm and may prolong the time between apnea and desaturation.
How does head position affect ETT placement after intubation?
Nose to chest → ETT tip moves towards the carina (risk of endobronchial intubation).
Nose away from chest → ETT tip moves away from the carina (risk of extubation).
Lateral rotation of the head → ETT tip moves away from the carina (risk of extubation).
What is the BURP maneuver?
The BURP maneuver involves applying Backward, Upward, and Rightward Pressure on the thyroid cartilage to improve glottic visualization during laryngoscopy.
What cuff pressure should be maintained to prevent tracheal ischemia?
The cuff pressure should be less than 25 cm H2O.
What is the best method to monitor cuff pressure?
Monitoring cuff pressure with a manometer is the best method to reduce the risk of tracheal ischemia.
What is the Murphy eye?
The Murphy eye is a small hole on the opposite side of the bevel of the endotracheal tube, providing an alternate passage for air movement if the tip becomes occluded.
How do you calculate the size of a pediatric endotracheal tube without a cuff?
ETT size without cuff = (age / 4) + 4.
How do you calculate the size of a pediatric endotracheal tube with a cuff?
ETT size with cuff = (age / 4) + 3.5.
How do you calculate the depth placement of an endotracheal tube?
Depth placement = Internal diameter x 3.
What is the purpose of inflating the LMA cuff?
Inflating the LMA cuff creates a seal over the larynx, allowing for positive pressure ventilation and shielding the larynx from pharyngeal secretions.
It does not reliably protect against gastric regurgitation.
What factors primarily affect the integrity of the LMA seal?
The integrity of the seal is primarily dependent on size and position, and less dependent on cuff volume or pressure.
What is the maximum positive pressure ventilation (PPV) pressure for LMA?
Max PPV pressure = 20 cm H2O.
What is the target cuff pressure for LMA?
Max cuff pressure = 60 cm H2O (target = 40 - 60 cm H2O).
What should be considered if cuff pressure exceeds 60 cm H2O and a good seal cannot be achieved?
The LMA may be improperly positioned, the patient inadequately anesthetized, or there may be a partial or complete laryngospasm.
What effect does nitrous oxide have on the LMA cuff?
Nitrous oxide diffuses into the cuff, increasing cuff pressure. Use a manometer when using N2O.
What is the most common cause of nerve injury related to LMA use?
Cuff overinflation is the most common cause of nerve injury.
The lingual, hypoglossal, and recurrent laryngeal nerves are at risk.
What complications can arise from cuff overinflation?
Cuff overinflation increases the risk of sore throat and pharyngeal necrosis.
What are the contraindications for using an LMA?
The LMA should not be used in cases of:
- Risk of gastric regurgitation and aspiration (e.g., full stomach, hiatal hernia, small bowel obstruction, symptomatic GERD, delayed gastric emptying)
- Airway obstruction at the level of the glottis or below
- Patient at risk of tracheal collapse (tracheomalacia or external tracheal compression)
- Poor lung compliance
- High airway resistance
What are the three ways to create a surgical airway?
- Percutaneous cricothyroidotomy with transtracheal jet ventilation (usually an emergent situation)
- Surgical cricothyroidotomy (usually an emergent situation)
- Tracheostomy (usually a controlled situation)
How is percutaneous cricothyroidotomy with transtracheal jet ventilation performed?
It is performed by inserting a large-bore needle through the cricothyroid membrane and ventilating with a high-pressure oxygen source, such as a jet ventilator.
What is required for transtracheal jet ventilation?
A high-pressure oxygen source (50 psi) during inspiration. Exhalation is passive, and upper airway obstruction can prevent exhalation (risk of barotrauma).
How is cricothyroidotomy performed?
By creating a small, horizontal incision through the cricothyroid membrane, and then inserting a cuffed endotracheal tube through the hole.
What is a contraindication for cricothyroidotomy?
Cricothyroidotomy is contraindicated in children less than 6 years of age (some texts say 10 years).
Why is tracheostomy less attractive for emergent situations?
It tends to require more time than cricothyroidotomy.
Are there any absolute contraindications to tracheostomy?
No, there are no absolute contraindications to tracheostomy.
What does the ASA Difficult Airway Algorithm provide?
A step-by-step method for dealing with anticipated and unanticipated difficult airway.
What neuromuscular blocker is recommended if proceeding with anesthetic induction?
Rocuronium (+ sugammadex if needed) instead of succinylcholine.
What is emphasized throughout the airway management process?
Optimizing oxygenation, limiting attempts, and being aware of time and oxygen saturation.
What are the primary objectives in a ‘can’t ventilate and can’t intubate’ scenario?
Call for help, place a supraglottic airway device, and possibly awaken the patient.
What should be attempted if a supraglottic airway device does not resolve the situation?
Alternative intubation approaches as preparation for emergency invasive airway.
What are some options for emergency invasive airway access?
Surgical cricothyrotomy, percutaneous cricothyrotomy with jet ventilation, rigid bronchoscopy, and ECMO.
What strategies are recommended for extubation?
Enlist skilled help, optimize oxygenation, use an airway exchange catheter (in adults), and consider elective tracheostomy.
What does the Difficult Airway Society Difficult Airway Algorithm (DAS DAA) include?
The DAS DAA includes 4 plans with clear instructions for succeeding or failing at each step.
What is Plan A of the DAS DAA?
Plan A involves facemask ventilation and tracheal intubation.
What happens if tracheal intubation succeeds in Plan A?
If tracheal intubation succeeds, proceed with laryngoscopy.
What should be done if intubation fails in Plan A?
If intubation fails, follow Plan B.
What is Plan B of the DAS DAA?
Plan B focuses on maintaining oxygenation through SAD insertion.
What are the options if SAD ventilation fails in Plan B?
Options include: 1. Wake the patient up 2. Intubate trachea via the SAD 3. Proceed without intubating the trachea 4. Tracheostomy or cricothyroidotomy.
What is Plan C of the DAS DAA?
Plan C involves facemask ventilation as a final attempt.
What does CICO stand for in Plan C?
CICO stands for Can’t Intubate, Can’t Oxygenate.
What happens if facemask ventilation succeeds in Plan C?
If it succeeds, wake the patient up.
What is Plan D of the DAS DAA?
Plan D is emergency front of neck access via cricothyroidotomy.
When should extubation be performed?
Extubation should be performed when the patient is deep or awake - NOT in-between!
How should the decision to extubate be made?
The decision of when to extubate should be made on a patient-to-patient basis.
What are the risks associated with awake extubation?
Risks associated with awake extubation include increased SNS stimulation, increased ICP, increased IOP, and increased IAP.
What are the risks associated with deep extubation?
Risks associated with deep extubation include airway obstruction and aspiration.
What is required for extubation of the difficult airway?
Extubation of the difficult airway requires the same degree of thought and planning required for the initial intubation.
What are some techniques for extubating the difficult airway?
Techniques for extubating the difficult airway include:
• Extubating fully awake
• Extubating over a flexible fiberoptic bronchoscope
• Extubating asleep and then placing an LMA
• Using an airway exchange catheter
What is a common indication for retrograde intubation?
Unstable cervical spine
Most common use of retrograde intubation.
When is retrograde intubation indicated regarding airway bleeding?
Upper airway bleeding when visualization of the glottis is not possible.
When is it best to use retrograde intubation?
When intubation has failed but ventilation is still possible.
Retrograde intubation requires time (~ 5-7 minutes for experienced practitioners).
Can retrograde intubation be performed on awake patients?
Yes, retrograde intubation can be performed in an awake patient.
