Respiratory IV: Airway Management
How does a CRNA insert a Combitube and anatomically, what does each of the cuffs occlude?
- The Combitube is blindly inserted into the hypopharynx -Inflating the oropharyngeal balloon (proximal cuff) occludes the hypopharynx - Inflating the distal balloon occludes the esophagus (usually)
What is the difference between an LMA ProSeal and the LMA Classic?
- The LMA ProSeal has a better seal and has a max pressure for PPV < 30 cm H2O (LMA Classic is < 20 cm H2O)
What are the four special features of the LMA Fastrach?
1. Metal handle (not suitable for use in the MRI suite) 2. Specially designed ETT (uses a high-pressure cuff) 3. Tube pusher 4. Epiglottic elevating bar
What are the movements of the FOB?
Non-dominant = moves the lever Dominant hand = holds the cord
What is the normal inter-incisor gap?
Normal = 2-3 finger breadths or 4 cm Long incisors reduce the gap Buck teeth increase the risk of dental damage
When dealing with a obese pt, what position should you have them in order to intubate?
The HELP position (Head Elevated Laryngoscopy Position) by using blankets or a positioning device to elevate the head and upper torso Optimal positioning is achieved when the sternum and the external auditory meatus are in the same horizontal plane. Also, putting the bed in reverse T position unloads the diaphragm and may prolong the time between apnea and desat.
What is so special about the LMA Fastrach?
The LMA fastrach is an intubating LMA. The LMA can be removed after intubation, or it can remain in place throughout the procedure (this leads to a higher incidence of sore throat and hoarseness).
What does the mandibular protrusion test (upper lip bite test) assess and how is it performed?
The MPT assesses the function of the temporomandibular joint. The pt is asked to sublet the jaw, and the position of the lower incisors is compared to the position of the upper incisors.
What joint is imperative in order to properly put the pt in the sniffing position? What's the normal flexion and extension of said joint?
The ability to put the pt in the sniffing position is dependent on the Atlanta-occipital joint mobility. Normal AO flexion and extension = 90-165 degrees Normal AO extension = 35 degrees (laryngoscopy will be difficult if < 23 degrees)
What is the benefit of a ETT without a Murphy's eye?
The cuff is closer to the tip, and this architecture minimizes the risk of endobronchial intubation. Useful in pediatrics.
What should the ETT cuff pressure be?
The cuff pressure should be less than 25 cmH2O so as to not cause tracheal ischemia.
What is the LMA Supreme?
The disposable version of the ProSeal
What are four ways to minimize cuff pressure?
The literature says it's unlikely you'll be able to accurately access the pressure inside the cuff and that we're underestimating the pressure exerted on the tracheal mucosa. 1. Use a manometer after intubation and periodically during the case 2. Fill the cuff with the same O2/N2O mixture that you will use during the case 3. Fill the cuff with water or saline. Provides a more stable cuff pressure, but it takes longer to deflate (really bad if there's an airway fire) 4. Use an ETT with a Lanz pressure-regulating valve
Which balloon is inflated first and what's the volume of air that each balloon can hold?
The oropharyngeal balloon is inflated first (Size 37 = 40-85 mL and Size 41 = 40-100 mL + option for additional 50 mL) The distal cuff is inflated second (Both sizes = 5-12 mL)
What are we assessing during the mallampati exam?
The oropharyngeal space. It helps us quantify the size of the tongue relative to the volume in the mouth. The more space the tongue occupies, the less space there is to work.
What is the ideal head/neck position while using the Bullard?
The pts head and neck must stay in a neutral or slightly flexed position - any extension will make glottic visualization more difficult.
Nose to chest pushes the tube where?
towards the carina (2 cm)
What is the relationship between the stylet of the Bullard and the ETT?
- Stylet and ETT sit to the right of the blade, the stylet can be manipulated to position the ETT over the glottis -Lubricate the stylet - The ETT may hangup on the right arytenoid cartilage, but you can fix this with cricoid pressure or lifting the blade anteriorly
What are the physical signs of Treacher Collins?
- Small mouth - Small/underdeveloped mandible - Nasal airway is blocked by tissue (choanal atresia) - Ocular and auricular anomalies
What is the difference between the Bullard and DVL as well as FOB?
- Compared with DVL, the Bullard causes less cervical spine displacement - Compared to FOB, intubation with the Bullard is usually faster
What is a lighted stylet and what pt population is it useful in?
- The lighted stylet is a blind technique that transilluminates the anterior neck to facilitate endotracheal intubation - Useful in pts with microstomia (small mouth), mandibular hypoplasia and severe oropharyngeal bleeding - The lighted stylet is a blind technique. There's no camera obstruction from a bloody airway that would occur if using a FOB and Bullard.
What are a couple considerations when using a lighted stylet?
- When the lighted stylet is in the trachea, the light has to travel through less tissue, so you'll observe a well-defined circumscribed glow below the thyroid prominence. Less glow if the stylet is in the esophagus, obviously.
How is Trisomy 21 (Down syndrome) characterized?
- small mouth - Large tongue - Atlantoaxial instability - small subglottic diameter (subglottic stenosis)
What are the five relative contraindications to a FOB intubation?
1. Hypoxia (lack of time) 2. Secretions not relieved by suction or an antisialagogue 3. Hemorrhage that impairs visualization 4. Unvooperative patient (for an awake attempt) 5. Local anesthetic allergy (awake attempt) *There are no absolute contraindications
What are the six contraindications to a Combitube?
1. Intact gag reflex 2. Prolonged use (> 2-3 hrs) d/t risk of ischemia from oropharyngeal 3. Esophageal disease (Zenker's diverticulum) 4. Ingestion of caustic substances 5. Do NOT use a size 37-F in someone < 4ft 6. Do NOT use a size 41-F in someone < 6ft *There are no options for pts < 4ft *Zenker's diverticulum is a condition where diverticulum (pouches) form in the pharyngeal mucosa
What are the 4 disadvantages of the lighted stylet?
1. It's difficult to use in the patient with a short, thick neck 2. It should not be used in an emergency or a can't ventilate can't intubate scenario 3. It's a blind technique and should not be used in the presence of a tumor, foreign body, airway injury, or epiglottis 4. Do NOT use in a pt with a traumatic laryngeal injury
What are the three reasons why the cuff pressure would exceed 60 cm H2O and you cannot get a good seal?
1. LMA is improperly positioned 2. pt is inadequately anesthetized 3. partial or complete laryngospasm
What are the six steps you should take if you observe gastric contents inside the airway tube of the LMA?
1. Leave the LMA in place. There may be gastric contents behind the LMA cuff. 2. Place the pt in the trendelenburg position and deepen the anesthetic if necessary. 3. Give 100% oxygen via ambu bag (if gastric contents are present inside the breathing circuit you don't want to push them into the lungs) 4. Use a low FGF and low Vt 5. Use a flexible suction catheter to suction through the LMA 6. Use a FOB to evaluate the presence of gastric contents in the trachea. If present, then consider intubation and aspiration protocols
What are the six risk factors for difficult supraglottic device placement?
1. Limited mouth opening 2. Upper airway obstruction (anything that prevents passage of the device into the pharynx) 3. Altered pharyngeal anatomy (anything that prevents a seal) 4. Poor lung compliance (requires excessive PIP) 5. Increased airway resistance (requires excessive PIP) 6. Lower airway obstruction
What are the two causes of angioedema and what are there treatments?
1. ACEi (enalaprilat is the only ACEI available IV) Treatment = Epinephrine, antihistamines, steroids (just like anaphylaxis) 2. Hereditary angioedema (C1 esterase deficiency) Treatment = C1 esterase concentrate or FFP
What are the five risk factors for difficult invasive airway placement?
1. Abnormal neck anatomy (tumor, hematoma, abscess, hx of radiation) 2. Obesity (difficult to identify the cricothyroid membrane) 3. Short neck (difficult to identify the cricothyroid membrane) 4. Laryngeal trauma 5. Limited access to the cricothyroid membrane (halo, neck flexion deformity)
What are the six complications of applying cricoid pressure?
1. Airway obstruction 2. Diff. with DL 3. Impaired glottic visualization 4. Difficult intubation 5. Reduced lower esophageal sphincter pressure 6. Esophageal rupture if pt is actively vomiting
What are some key points to a FOB intubation?
1. Anti-fog solution should be applied to the tip of the FOB 2. Glycopyrrolate 0.2 mg IV minimizes secretions 3. Vasoconstrictors minimize epistaxis during nasal approach 4. The Williams or ovassapian airway helps the FOB stay midline, may stimulate the gag reflex in the awake pt. 5. A second provider can grab the tongue with a 4x4 and pull it anteriorly. This clears space for the FOB 6. An LMA can be used in conjunction with the FOB
What are the other two indications for a FOB?
1. C-spine limitation: severe cervical stenosis, cervical fracture, Chiari malformation, vertebral artery insufficiency 2. Limited mouth opening: TMJ disease, facial burns, mandibular-maxillary fixation
What are the two key elements of the sniffing position?
1. Cervical flexion: moves the chin to the chest 2. Atlanto-occipital joint extension: Extends the head on the neck
What is the tendency of airway device placement to activate the SNS (from most to least stimulating)?
1. Combitube 2. DVL 3. FOB 4. LMA
What are the five contraindications of a NPA?
1. Cribriform plate injury - LeFort 2 or 3 fracture - Basilar skull fracture - CSF rhinorrhea - Racoon eyes - Periorbital edema 2. Coagulopathy (risk of epistaxis) 3. Previous transsphenoidal hypophysectomy 4. Previous Caldwell-Luc procedure 5. Nasal fracture
What 8 conditions impair AO mobility?
1. Degenerative joint disease 2. Rheumatic arthritis 3. Ankylosing spondylitis 4. Trauma 5. Surgical fixation 6. Klippel-Feil 7. Down syndrome 8. DM (joint glycosylation)
What are the four key features of the LMA Flexible?
1. Flexible 2. Wire-reinforced (not suitable for use in the MRI suite) 3. Longer than the LMA Classic 4. Narrower than the LMA Classic Useful for head and neck surgery where the airway tube of the LMA classic would limit access to the surgical site.
What two types of pts is the Combitube useful in?
1. Full stomach 2. Klippel-Feil syndrome (doesn't require neck extension to place)
What are the 3 "How to" steps in using the Eschmann Introducer (Bougie)?
1. Hook the angled tip under the epiglottis (grade 3 view) 2. Advance the tip into the trachea (23-25 cm). Lubricating the EI will facilitate "railroading" the ETT over it into the trachea 3. Feeling the click of the tracheal rings confirms placement
What are the six guidelines for the use of an LMA for a laparoscopic procedure?
1. Observe the "15" rule: Use <15 degree tilt, < 15 cm H2O IAP, and < 15 minutes of insufflation 2. Select an LMA that allows for gastric drainage (LMA ProSeal or Supreme) 3. Use in pts with normal BMI 4. Observe traditional NPO fasting guidlines 5. Avoid light anesthesia 6. Be an experienced LMA user
What are the 7 benefits of a Combitube?
1. Provides a secure airway (aspiration protection) 2. Ability to decompress the stomach 3. Useful for the obese population 4. Uses a blind insertion technique (minimal training required) 5. Does not require neck extension 6. Allows high ventilatory pressures (up to 50 cm H2O) 7. Does not need to be taped to the pt
What are the four contraindications of an LMA?
1. Risk of gastric regurgitation and aspiration: full stomach, hiatal hernia, small bowel obstruction, symptomatic GERD, delayed gastric emptying 2. Airway obstruction at the level of the glottis or below the glottis 3. Poor lung compliance 4. High airway resistance
Once inserted, what are the steps to ventilate the pt using the Combitube?
1. Since the tip usually enters the esophagus, attempt ventilation through the blue (proximal or esophageal) lumen 2. If the tip enters the trachea, then you can ventilate through the clear (distal or tracheal) lumen. 3. Tip of the tracheal lumen is open, tip of esophageal lime in closed
What are the six instances we would use a Bullard Laryngoscope?
1. Small mouth opening (minimum mouth opening = 7 mm) 2. Impaired cervical spine mobility 3. Short, thick neck 4. Treacher Collins syndrome 5. Pierre-Robin syndrome 6. Adult and pediatric sizes are available *There are NO absolute contraindications
What are the seven benefits of using the lighted stylet?
1. Useful for the anterior airway 2. Useful with small mouth opening 3. Requires very little manipulation of the neck 4. Less stimulating than DVL 5. Less sore throat than DVL 6. Can be used for oral or nasal intubations 7. Useful for cervical spine abnormality, Pierre-Robin syndrome, severe burn contractures
Besides laryngospasm, what other complications (4) are there from a OPA or NPA?
1. Vomiting (if the gag reflex is intact) 2. Dental injury (if the pt bites down) 3. Oropharyngeal trauma 4. Ischemia (compresses blood flow to affected areas)
What are the ten risk factors for a difficult intubation?
1. small mouth opening 2. Long incisors 3. Prominent overbite 4. High, arched palate 5. Mallampati class 3 or 4 6. Retrognathic jaw 7. Inability to sublux jaw 8. Short, thick neck 9. Short thyromental distance 10. Reduced cervical mobility
What other complications (2) does cuff overinflation cause?
1. sore throat 2. pharyngeal necrosis
What should the cuff pressure on a combitube not exceed?
Cuff pressures should not exceed 60 cm H2O Overzealous inflation of the cuffs can rupture the esophagus
What are the preop fasting guidelines (2,4,6,8 hrs)?
2 hrs = clear liquids 4 hrs = breast milk 6 hrs = nonhuman milk, infant formula, solid food 8 hrs = fried or fatty foods Ingestion of clear liquids 2 hrs before surgery reduces gastric volume and increases gastric pH --> reduces risk of mendelson syndrome (gastric pH < 2.5 and gastric volume > 25 mL (0.4 ml/kg))
What is the max PPV pressure when using an LMA?
20 cm H2O
What mallampati class (1-4) is associated with a more difficult intubation?
3-4
What is the max cuff pressure of an LMA?
60 cm H2O (target = 40-60 cm H2O)
What is Ludwig's Angina?
A bacterial infection characterized by a rapidly progressing cellulitis in the floor of the mouth. -Most significant concern is posterior displacement of the tongue resulting in complete supraglottic airway obstruction.
What grade view on the Cormack and Lehane grading system does the Eschmann introducer provide the MOST significant benefit?
A grade 3 view
What type of cuff is a microthin cuff and what are its benefits?
A high volume, low pressure cuff Benefits over a standard high-volume, low-pressure cuff include: 1. Lower pressure on the tracheal mucosa 2. Better protection against liquid aspiration
What is angioedema?
Angioedema is a sudden swelling of the face, palate, tongue, and airway.
What is the most common cause of nerve injury when using an LMA and what three nerves are at risk?
Cuff overinflation 1. Lingual 2. Hypoglossal 3. RLN Others: LMA is too small, lidocaine lubrication, and traumatic insertion
What's the best way to secure the airway with a pt that has Ludwig's angina?
Awake nasal intubation or awake tracheostomy Retrograde intubation is contraindicated in pts with an infection above the level of the trachea.
What are the five independent risk factors for difficult mask ventilation?
BONES: 1. Beard 2. Obese (BMI > 26) 3. No teeth 4. Elderly (age > 55) 5. Snoring
How much cricoid pressure should be applied before and after LOC?
Before LOC = 20 Newtons or 2 kg After LOC = 40 N or 4 kg
In what scenario should an LMA be used even if the patient is at risk of aspiration?
Can't ventilate and can't intubate In this situation, hypoxemia (not aspiration) is the greatest risk to the patient.
What does the mnemonic PUSH stand for when describing the different classes in the mallampati score?
Class 1: Pillars, Uvula, Soft palate, Hard palate Class 2: Uvula, Soft palate, Hard palate Class 3: Soft palate, Hard palate Class 4: Hard palate
What are the three classes of the MPT?
Class 1: Pt can move LI past UI and bite the vermillion of the lip (where the lip meets the facial skin) Class 2: Pt can move LI in line with UI Class 3: Pt cannot move LI past UI (increased risk of difficult intubation)
What must you watch out for in a neonate with Klippel-Feil?
Congenital fusion of cervical vertebrae --> neck rigidity
What anatomical structures is the cuff (distal, proximal, sides) of an LMA adjacent too?
Distal end: Upper esophageal sphincter (cricopharyngeus muscle) Sides: Pyriform sinuses Proximal end: Base of the tongue
For pediatrics, how do you calculate the ETT size (without a cuff and with a cuff). Also, the calculation to determine the depth.
ETT size without cuff = (age/4) + 4 ETT size with cuff = (age/4) + 3.5 Depth placement = ID x 3
What is the gold standard for managing a difficult airway?
FOB in the awake, spontaneously ventilating patient Like we haven't heard this enough
How do you manipulate the Ballard handle to obtain glottic exposure?
Glottic exposure occurs when the handle (blade) is pulled straight up (90 degree angle to the spine) - not up and caudally as you would with direct laryngoscopy.
In general, how does the Cormack and Lehane score correlate with intubation?
Grade 1 & 2A: Easier intubation Grade 2B & 3: Harder intubation Grade 4: Requires an alternative approach to intubation
What is a Grade 2A and 2B view?
Grade 2A: You can see the posterior region of the glottic opening Grade 2B: Only see the corniculate cartilages and posterior vocal cords. You cannot see any part of the glottic opening.
What TMD is indicative of a difficult laryngoscopy?
If the TMD is less than 6 cm (3 finger breadths) or greater than 9 cm
What is the "hold-up sign" when using a Eschmann introducer?
If you don't feel clicks, then you can look for the "hold-up sign" as a secondary way to confirm placement. You will feel the EI "hold-up" as it encounters resistance at the carina (35-40 cm) - Only use the "hold-up" sign if you don't feel clicks but you think you're in the trachea, as this technique increases the risk of tracheal and/or bronchial trauma *Keep the laryngoscope in place during the entire intubation process.
What is the purpose of the Murphy eye?
It's there to provide an alternative passage for air movement in the case the tip of the ETT becomes occluded or abut the tracheal wall.
What are some characteristics of the LMA ProSeal?
Its an adaptation of the classic LMA. It's a double lumen LMA. -Gastric drain tube (the second lumen) for easy gastric decompression - Do NOT place suction directly to the drain. Pass OGT through second lumen. - Larger mask - Bite block
Beckwith syndrome
Large tongue
What two factors contribute to a TMD less than 6cm and what three factors contribute to a TMD more than 9cm?
Less than 6 cm: 1. Mandibular hypoplasia 2. Small submandibular space More than 9 cm: 1. The larynx assumes a more caudal position 2. Because the tongue is fixed at the hyoid bone, the tongue moves caudally as well 3. These changes shift the glottic opening beyond the line of sight.
What are two downsides of FOB under general anesthesia?
Loss of pharyngeal tone and upper airway obstruction.
How do you size up a NPA?
Measure from the care to the earlobe or the angle of the mandible Too short: fails to relieve the obstruction Too long: NPA displaces the epiglottis towards the glottis
How do you size up a OPA?
Measure from the corner of the mouth to the earlobe or the angle of the mandible - Too short: OPA can obstruct the airway by causing the tongue to kink - Too long: OPA displaces the epiglottis towards the glottis
What occurs to the LMA when using N2O?
N2O diffuses into the cuff--> increases cuff pressure Use a manometer when using N2O.
Which airway (OPA or NPA) is better tolerated in a lightly anesthetized pt?
Placing an airway into a lightly anesthetized pt can precipitate a laryngospasm. An NPA is better tolerated in this situation
What is the LMA C-Trach?
The C-Trach is very similar to the Fastrach, but it includes a camera so you can visualize intubation
What are the different types of OPAs and what are there specific uses?
Relieve upper airway obstruction. Opens airway by displacing the tongue and epiglottis from the posterior wall of the pharynx.
What characteristics would you see in a kid with Goldenhar?
Small/underdeveloped mandible Cervical spine abnormality
Cri du chat
Small/underdeveloped mandible Laryngomalacia Stridor
How is the congenital condition Pierre Robin categorized?
Small/underdeveloped mandible (micrognathia or mandibular hypoplasia) A tongue that falls back and downwards (glossoptosis) Cleft palate Neonate often requires intubation
Steep trendelenburg position has what affect on the position of the ETT?
Steep T causes stomach contents to shift towards the chest --> increases risk of endobronchial intubation
What are the borders of the submandibular space?
Superior border = Mentum Inferior border = Hyoid bone Lateral border = Either side of the neck
When should we use the Eschmann Introducer?
To facilitate intubation of a very anterior glottis. Best time to use the EI = Grade 3 view Next best time to use the EI = Grade 2b view Worst time to use the EI = Grade 4 view (the chance of successful intubation is unacceptably low)
What is the relationship between LMA and asthma?
VA obtund the pulmonary reflexes. However, upon emergence if there is an ETT in place the patient may cough or suffer bronchospasm Asthmatic patients have a higher likelihood to experience wheezing during emergence. LMAs sits over the glottis and are less stimulating than ETTs in asthmatic pts.
What is the Cormack and Lehane score?
Your grade view of the glottis on intubation
Lateral rotation of the head moves the tip where?
away from the carina (0.7 cm)
Nose away from the chest pulls the tip where?
away from the carina (2 cm)
