AIRWAY Flashcards
Nasal passages includes
septum, turbinates, adenoids
Function of nasal passages
accounts for 2/3 of total upper airway resistance
Humidifiy
filter and warm
Innervation of nasal passages
Branches of the trigeminal nerve (CN V)
Oral cavity includes
Teeth
Tongue (Predominate cause of airway resistance in oral cavity)
Hard palate soft palate
Innervation of oral cavity
Trigeminal Nerve (CN V) Hard and soft palate and * anterior 2/3 tongue Glossopharyngeal (CN IX) Posterior 1/3 tongue Soft palate Oropharynx
The pharynx connects
The nasal and oral cavities
Pharynx is divided into
Nasopharynx (Border is soft palate)
Oropharynx (Border is the epiglottis Tonsils, Uvula)
Hypopharynx/ Larygopharynx
Innervation of the pharynx
Glossopharyngeal (CN IX)
Vagus (CN)
Larynx is located
Located at C4 - C6
in the adult
Larynx functions:
Airway protection, Respiration,
Phonation
Inlet to trachea
Thyroid Cartilage (Unpaired cartilage)
Large and most prominent
Anterior attachment for vocal cords
Epiglottis (Unpaired cartilage)
Covers opening to the larynx during swallowing
: cartilaginous flap that serves as the anterior border of the laryngeal inlet. It functions to divert food away from the larynx during the act of swallowing
Cricoid cartilage (Unpaired cartilage)
Only complete cartilaginous signet-shaped ring
Narrowest portion of the pediatric airway
Larynx made is up of?
9 cartilages
3 pair and
3 unpaired- Thyroid cartilage, cricoid cartilage and epiglottis.
Paired cartilages of the larynx
Arytenoid
Corniculate
Cunieform
Arytenoid
Posterior attachment for the vocal cords
falsely identified in an anterior airway
Corniculate
Posterior portion of the aryepiglottic fold
cuneiform
In the aryepiglottic fold, not always present
Lateral to the corniculates
Vocal Cords are formed and attached
Appear pearly white
Formed by the thyroarytenoid ligaments
Attached anteriorly tot he thyroid cartilage and posteriorly to the arytenoid cartilages.
Glottic Opening
Triangular fissure between the cords
Narrowest portion of the adult airway.
Intrinsic Laryngeal Muscles Glottic Opening
Lateral Cricoarytenoid
Arytenoid Muscles
Posterior Cricoarytenoid
Lateral Cricoarytenoid Muscle
adducts the vocal cords
Arytenoid Muscles
Oblique arytenoids and transverse arytenoids
Adduct the vocal cords
Posterior Cricoarytenoid muscle
The only vocal cord abductor
Intrinsic Laryngeal Muscles Vocal Cord Length
Cricothyroid
Thyroarytenoid
Vocalis
Cricothyroid Muscle
Tenses/Elongates vocal cords
Thyroarytenoid Muscle
Relaxes/ Shortens vocal cords
Vocalis Muscle
Relaxes/ shortens vocal cords
Intrinsic Laryngeal Muscles
Control the movements of the laryngeal cartilages.
-Control the length and tension of the vocal cords and the size of the glottic opening
Cricothyroid muscle is innervated by
The external branch of the superior laryngeal nerve a branch of the Vagus nerve (CN X)
All others innervated by the recurrent laryngeal nerve a branch of the Vagus nerve (CN X)
Extrinsic Laryngeal Muscles
Move larynx as a whole
Suprahyoid Group
Infrohyoid Group
Suprahyoid group
Suprahyoid Group
Stylohyoid, mylohyoid, geniohyoid, digastric
Raises larynx cephalad
Infrahyoid Group
Sternothyroid, sternohyoid, thyrohyoid, omohyoid
Moves larynx caudad
Trachea
Fibro muscular Tube
10 to 20 cm length 22 diameter
16-20 U shaped cartilages
Bifurcates lower border T4
Trachea
Fibro muscular Tube
10 to 20 cm length 22 diameter
16-20 U shaped cartilages
Bifurcates lower border T4- Carina
Carina-Trachea divides into Right & Left mainstem bronchi
Right bronchi is 2.5 cm long with angle of 25
Left bronchi is 5 cm with an angle 45
Airway assessment
Critical:
“No single test has been devised to predict a difficult airway accurately 100% of the time”
p. 1651
Previous difficult intubation should always raise suspicion
Review prior anesthetic records when possible for guidance on prior AW management
Airway assessment goal
Is to identify potential airway problems and identify a difficult airway.
Airway Assessment
Thorough and systematic airway assessment and physical exam should be performed in the preoperative period.
Followed by a patient specific plan for anesthesia.
Airway Assessment Questions to ask
Radiation or burn to head/neck? C-spine pain of LROM? TMJ pain? Rheumatoid arthritis? Ankylosing spondylitis? Abscess or tumor? Prior intubation or tracheotomy? Snoring or sleep apnea? Dysphagia or stridor?
Airway Assessment
General appearance --Head, neck size and fullness Range of motion Dentition Mouth Tongue, lips, tissues, gums Mouth opening --30-40 mm or 2-3 fingers
Airway Assessment
Body habitus Mallampati classification* Thyromental distance* Mandibular Protrusion Test* History of previous difficult airway Diagnosis Planned surgery
Components of the Physical Examination of the Airway
• Visual inspection of the face and neck
• Assessment of mouth opening
• Evaluation of oropharyngeal anatomy and dentition
• Assessment of neck range of motion (ability of the patient to
assume the sniffing position)
• Assessment of the submandibular space
• Assessment of the patient’s ability to slide the mandible
anteriorly (test of mandibular prognathism)
Oropharyngeal Evaluation
–Mallampati Classification
Correlates the oropharyngeal space with the ease of direct laryngoscopy and tracheal intubation
Hypothesis:
When the base of the tongue is disproportionately large, the tongue overshadows the larynx resulting in difficult exposure of the vocal cords during laryngoscopy
Assessment:
Pt sitting upright, head neutral, mouth open as wide as possible and tongue maximally protruded. No AAAH!
Limited use as a stand alone test
Mallampati Classification
Class I
Class I: Faucial pillars, uvula, and soft palate are visualized.
Class II
Class II: Base of the uvula and soft palate are visualized.
Class III
Class III: Soft palate only is visualized.
Class IV
Class IV: Hard palate only is visualized.
Cormack and Lehane Score
Grade I: most of the glottis visible
Grade II: Only the posterior portion of glottis visible
Grade III: Only epiglottis visible
Grade IV: No airway structures visualized
Mallampati Classification and the Cormack and Lehane Score
Cormack and Lehane score is the laryngoscopic view of the glottis
Mallampati class is correlated to what can be seen on direct laryngoscopy (Cormack and Lehane score)
Cormack and Lehane Score
Grade I: most of the glottis visible
Grade II: Only the posterior portion of glottis visible
Grade III: Only epiglottis visible
Grade IV: No airway structures visualized
Mallampati Classification and the Cormack and Lehane
Cormack and Lehane score is the laryngoscopic view of the glottis
Mallampati class is correlated to what can be seen on direct laryngoscopy (Cormack and Lehane score)
Cormack and Lehane Score
Grade I: most of the glottis visible
Grade II: Only the posterior portion of glottis visible
Grade III: Only epiglottis visible
Grade IV: No airway structures visualized
Thyromental Distance
Distance from lower border of mandible to thyroid notch with neck fully extended
Normal 6-6.5 cm or 4 Fingerbreadths
Difficult intubation < 3 fingers, receding mandible; “anterior airway”
Mandibular Protrusion Test
Class A: Lower incisors can be protruded anterior to the upper incisors
Class B: The lower incisors can be brought to the edge with the upper incisors.
Class C: The lower incisors cannot be brought to the edge with upper incisors
The inability to extend the lower incisors beyond the upper incisors may be indicative of difficult laryngoscopy.40 A similar evaluation, the upper lip bite test (ULBT) described by Khan and colleagues, has been shown to predict difficult laryngoscopy with higher specificity and less interobserver variability than the Mal- lampati classification; an inability of the lower incisors to bite the upper lip is associated with more difficult laryngoscopy.41,42
The inability to extend the lower incisors beyond the upper incisors may be indicative of difficult laryngoscopy.40 A similar evaluation, the upper lip bite test (ULBT) described by Khan and colleagues, has been shown to predict difficult laryngoscopy with higher specificity and less interobserver variability than the Mal- lampati classification; an inability of the lower incisors to bite the upper lip is associated with more difficult laryngoscopy.41,42
Preparing for induction M S M A I D S
Monitors on and settings appropriate Suction on and at head of bed Machine checked, means of positive pressure ventilation Airway IV Drugs (emergency and case/pt specific) Special equipment
Pre-oxygenation Goal
Increase O2 concentration in functional residual capacity (FRC) by “washing out” nitrogen (79% in RA) in the FRC with oxygen
FRC= volume of air left in the lung at end of passive expiration
3-5 minutes of “tight” mask fit during normal tidal breathing with100% FiO2 at> 6L/min flow = 10 minutes of safe apnea time
4 vital capacity breaths within 30 seconds with 100% FiO2 at >6L/min= 5 minutes of safe apnea time
8 breaths over 60 seconds will > effectiveness over 4br/ 30sec
An end-tidal concentration of oxygen greater than 90% is considered to maximize apnea time.
Aspiration
Loss of AW reflexes has major risk of aspiration
Premise of NPO guidelines
High risk:
full stomach, symptomatic gastroesophageal reflux disease (GERD), hiatal hernia, presence of a nasogastric tube, morbid obesity, diabetic gastroparesis, or pregnancy
Aspiration prophylaxis: decrease gastric volume and to increase gastric fluid pH
nonparticulate antacids (e.g., Bicitra), promotility drugs (e.g., metoclopramide), and H2-receptor antagonists. These drugs may be used alone or in combination.
Airway Set up
Appropriate sized face mask* Means of Positive Pressure Ventilation (PPV)-> ambu-bag, machine circuit; O2 source Suction on and easily accessible Tongue depressor Appropriate sized oral and nasal airways* Laryngoscope handle* 2 different blades* Endotracheal Tube (ETT)- 2 sizes* Stylet Syringe Appropriate sized Laryngeal Mask Airway (LMA) (difficult airway)* Tape
Anesthetic Face Masks
Many types sized for adult and pediatric use
Patient characteristics may predict difficult mask fit
Examples: Beard, edentulous, short mandible
Head strap and potential nerve injuries
Technique:
Hold mask in Left Hand and Reservoir Bag in Right. Put Thumb on upper aspect of mask, index and middle fingers on lower aspect, and 4th/5th fingers under chin for chin lift/jaw thrust.
Predictors of Difficult Mask Ventilation
- Obstructive sleep apnea or history of snoring • Age older than 55 years
- Male gender
- Body mass index of 30 kg/m2 or greater
- Mallampati classification III or IV • Presence of a beard
- Edentulousness
The technique for mask ventilation is dependent on two key elements:
(1) maintenance of a seal between the facemask and the patient’s face and (2) an unobstructed upper airway.10 The mask is usually held with the left hand, with the thumb and index finger forming a C around the collar of the connector, the third and fourth digits on the ramus of the mandible, and the fifth digit on the angle of the mandible (Figure 55-11). The thumb and index finger are used to produce downward pressure to ensure a tight mask seal, while the remaining digits provide upward dis- placement of the mandible (jaw thrust) to aid with airway patency. The right hand is free to provide manual ventilation.
Mask Ventilation
Effectiveness is assessed by: chest rise, exhaled tidal volumes, pulse oximetry, and capnography. Adequate tidal volumes should be achieved with peak inspiratory pressures less than 20cm H2O.
higher pressures should be avoided to prevent gastric insufflation
NOT ADEQUATE @ <20 cm H2O?
airway patency and pulmonary compliance should be assessed.
Obstruction
Common problem during induction of anesthesia is airway obstruction by the tongue and epiglottis due to relaxation of the genioglossus muscle
Oral airways types
Berman (BOA) and Guedel. Adult sizes small BOA (80 mm) = Guedel #3 medium BOA (90) = Guedel #4 large BOA (100) = Guedel #5 Sized by measuring from the corner of a patient’s mouth to the angle of the jaw or the earlobe Complications/Precautions: Laryngospasm Bleeding Soft tissue damage Lingual nerve palsy Damage to teeth Worsening obstruction (mis-sized)
Oral airways
Because they place pressure on the base of the tongue and may come in contact with the epiglottis, oropharyngeal airways can precipitate coughing, retching, or laryngospasm if laryngeal and pharyngeal reflexes are not sufficiently blunted; therefore they are not appropriate for use in conscious patients.
A tongue depressor can be used to displace the tongue anteriorly as the oropharyngeal airway is inserted with the curvature facing anteriorly.
Nasal Airway/Trumpet
Used to provide passageway, nose pharynx beneath the relaxed and obstructing tongue
Diameter-French sizes 24, 26,…36
Length- estimated as distance from nares to meatus of ear
Lubricate!
Used in series (small to large) to dilate prior to elective nasal intubation
Usually tolerated better than oral airway during light anesthesia
Complications/Precautions:
epistaxis, nasal or basal skull fractures, adenoid hypertrophy, anticoagulants?
Nasal Airway Precaution
Nasal septal deviation is common in the adult population6; therefore the more patent side should be determined before passing instrumentation through the nasal passages (p. 1648)
Floor of the nasal cavity is the preferred pathway for passage of nasal airway devices7; improper placement of objects in the nose can result in avulsion of a turbinate (p. 1648)
The roof of the nasal cavity is formed by the cribriform plate, part of the ethmoid bone. This fragile structure, if fractured, can result in communication between the nasal and intracranial cavities and a resultant leakage of cerebrospinal fluid. Because the mucosal lining of the nasal cavity is highly vascular, vasoconstrictor should be applied, usually topically, before instrumentation of the nose to avoid epistaxis (p. 1648).
Nasopharyngeal airways should be well lubricated before insertion and inserted with the bevel facing the nasal septum. To avoid epistaxis, force should never be used during insertion of a nasopharyngeal airway.
Potential Hazards to Advanced Airway Management
Dental damage Soft tissue/mechanical injury Laryngospasm Bronchospasm Vomiting/Aspiration Hypoxemia/Hypercarbia SNS stimulation Esophageal/Endobronchial intubation
Laryngospasm
Laryngospasm: Laryngospasm is usually provoked by glossopharyngeal or vagal stimulation attributable to airway instrumentation or vocal cord irritation (e.g., from blood or vomitus) in the setting of a light plane of anesthesia (stage II of the Guedel classification), but it can also be precipitated by other noxious stimuli and can persist well after the removal of the stimulus. Treatment of laryngospasm includes removal of airway irritants, deepening of the anesthetic, and the administration of a rapid-onset neuromuscular blocking drug (NMBD), such as succinylcholine. Other tx: CPAP with 100% O2, Bilateral pressure at the laryngospasm notch between the condyle of the mandible and the mastoid process can be effective at treating laryngospasm by causing an intense, painful stimulus, which may function to terminate laryngospasm by arousing a semiconscious patient or by activating autonomic pathways.
Bronchospasm
Bronchospasm: Irritation of the lower airway by a foreign substance activates a vagal reflex–mediated constriction of bronchial smooth muscle, resulting in bronchospasm. Untreated bronchospasm can result in an inability to ventilate because of an extremely elevated airway resistance. Treatment includes a deepen- ing of anesthetic with propofol or a volatile agent and the administration of inhaled β2-agonist or anticholinergic medications.
SNS Stimulation
SNS stimulation: Endotracheal intubation, as well as laryngoscopy and other airway instrumentation, provides an intense nox- ious stimulus via vagal and glossopharyngeal afferents that results in a reflex autonomic activation, which is usually manifested as hypertension and tachycardia in adults and adolescents; in infants and small children, autonomic activation may result in bradycardia. Hypertension and tachycardia are usually of short duration; however, they may have consequences in patients with significant cardiac disease. Central nervous system activation as a result of airway management results in increases in electroencephalographic (EEG) activity, cerebral met- abolic rate, and cerebral blood flow, which may result in an increase in intracranial pressure in patients with decreased intracranial compliance.60 (p. 1654)
Predictors of Difficult Laryngoscopy
- Long upper incisors
- Prominent overbite
- Inability to protrude mandible
- Small mouth opening
- Mallampati classification III or IV • High, arched palate
- Short thyromental distance
- Short, thick neck
- Limited cervical mobility
Laryngoscopes and Blades
Handles-> check the battery! Adult Pediatric Blades-> check the light! Want one of each Macintosh (1-4) Miller (0-4)
Macintosh or Miller
Laryngoscope is held in the left hand.
Macintosh is most commonly used for adults, whereas the straight blades are typically used in pediatric patients.178 Curved blades provide greater room for passage of an ETT through the oropharynx, attributable to their larger flange, and are generally considered less likely to cause dental damage.179 Straight blades are preferred in patients with a short thyromental distance and usually provide a better view of the glottis in patients with a long, floppy epiglottis. Often, when one style of laryngoscope does not provide an adequate view of the glottis, the other may be more effective. For most adults, a Macintosh size 3 or a Miller size 2 blade is usually the proper size; in larger patients or patients with a very long thyromental distance, a larger blade may be more appropriate.
Endotracheal Tubes
Gold standard for AW management
Absolute indications:
full stomach
high risk for aspiration of gastric secretions or blood
critically ill
significant lung abnormalities (e.g., low lung compliance, high airway resistance, impaired oxygenation)
surgery requiring lung isolation
otorhinolaryngologic surgery where an SGA would interfere with surgical access (AW management discussed w/ surgeon)
anticipated need for postoperative ventilatory support
failed SGA placement
Others
surgical requirement for NMBDs,
positioning that does not allow quick access to the AW (e.g., prone, etc)
predicted difficult airway
prolonged procedures
ET Tubes (ETT)
A variety of types based on pt needs and surgical requirements
Common features:
Standard 15-mm adapter
high-volume, low-pressure cuff
Purpose: create a seal to protect against gastric aspiration
Ensures tidal volume delivered reached the lungs
beveled tip: facilitates passage through the vocal cords
“Murphy eye” additional distal opening in the side wall
Back-up portal for ventilation should the distal end of the lumen become obstructed by either soft tissue or secretions
Pilot balloon with one-way valve
Cuff inflation & assessment of cuff pressure
Minimal inflation volume to attain air leak ~20- 25cm H2O
ETT Cuff Pressure
Excessive cuff pressure may result in tracheal mucosal injury, vocal cord dysfunction from recurrent laryngeal nerve palsy, and sore throat. Monitoring the cuff pressure with a pressure gauge is recommended. When N2O is used as part of the anesthetic, cuff pressure should be periodically measured throughout the surgery; N2O diffusion into the cuff can result in increases in cuff pressure to potentially dangerous levels (p. 1666).
Black Intubation
Black intubation depth markers located 3 cm proximal to the cuff can be seen in some designs (see Fig. 5.1 ). These assist the accurate placement of the tracheal tube tip within the trachea. The vocal cords should be at the black mark in tubes with one mark, or should be between marks if there are two such marks. However, these are only rough estimates and correct tracheal tube position depth should always be confirmed by auscultation.
High Pressure-Low Volume:
High pressure-low volume:
- These can prevent the passing of vomitus, secretions or blood into the lungs.
- At the same time, they exert a high pressure on the tracheal wall. If left in position for long periods, they may cause necrosis of the tracheal mucosa.
High Volume - Low Pressure
High volume-low pressure:
These exert minimal pressure on the tracheal wall as the pressure equilibrates over a wider area ( Fig. 5.6 ). This allows the cuff to remain inflated for longer periods.
They are less capable of preventing the aspiration of vomitus or secretions. This is due to the possibility of wrinkles forming in the cuff.
Endotracheal Intubation
ETT size based on internal diameter (ID) Adult ETT want 2 sizes available Female: 6.5-7.0 mm id Male: 7.5-8.0 mm id Ideal position: distal end in mid-trachea 4 cm above the carina and 2 cm below the vocal cords Males approximately 23 cm Females approximately 21 cm IDx3= approximate depth Nasal vs. Oral Securement to maxilla (fixed) ALWAYS listen for bilateral breath sounds, look for bilateral chest rise and presence of end-tidal CO2!
Small ETTs
Smaller ETTs result in increased airway resistance and work of breathing, and ETTs with a smaller than 8-mm ID preclude therapeutic fiberoptic bronchoscopy. Larger ETTs are more likely to be associated with laryngeal or tracheal mucosal trauma and have a higher incidence of sore throat after general anesthesia. Generally, in patients intubated only for the purposes of a general anesthetic, a smaller ETT may be used than on the patient who will remain intubated in the medium to long term as a result of respiratory failure; typically a 7-mm ETT is used for women and an 8-mm ETT is used for men.
Nasotracheal Intubation
Nasotracheal intubation is generally indicated when the orotracheal route is not possible (e.g., when the mouth opening is severely limited) or when the need for surgical access precludes an orotracheal route. In addition, certain intubation techniques, such as blind intubation, awake intubation, and FSI, are significantly easier when performed through the nose. Nasotracheal intubation is relatively contraindicated in the setting of maxillary or skull base fractures.
Orotracheal
The orotracheal route is potentially less traumatic and presents a lower risk of bleeding, it usually allows for the placement of a larger ETT, and it provides for more options in terms of airway management techniques.
ETT Tubeplacement
The most important and objective indicator of endotracheal intubation, however, is the presence of a normal capnogram (carbon dioxide [CO2] waveform) for the presence of at least three breaths. Severe bronchospasm, equipment malfunction, cardiac arrest, or hemodynamic collapse may prevent the appearance of a capnogram tracing, despite proper ETT placement. If doubt remains, then fiberoptic bronchoscopy, although not routinely used, is very reliable at confirming ETT placement. (p.1670)
ETT Options
Preformed tubes, such as the nasal and oral Ring-Adair-Elwin (RAE) tubes, have a specific contour to maintain a low profile and to avoid surgical interference. Armored (reinforced) tubes have an embedded coil that minimizes kinking of the tube when it is subjected to angulation. Microlaryngeal tubes, which have small IDs with a longer length tube, are useful in laryngeal surgery or for specific applications, such as intubation through a cLMA. Other specialized tubes include laser-resistant tubes and both single- and double-lumen tubes that allow for one-lung ventilation.
Stylet
shaping the ETT with a malleable stylet into a hockey stick shape
60-degree angle formed 4 to 5 cm from the distal end
removed when the tip of the ETT is right at the level of the vocal cords
limits trauma to the tracheal mucosa
Optimal Intubating Position
Sniffing” position- aligns the 3 axis
Oral axis
Pharyngeal axis
Laryngeal axis
This position provides the most optimal visualization of the vocal cords
Allows for the most effective mask ventilation
Positioning is key for success especially for the novice practitioner
Sniffing Positions
Assessment of a patient’s ability to assume this position should be included in the airway examination; an inability to extend the neck at the atlantooccipital joint is associated with difficult laryngoscopy (p. 1653).
Alignment of three anatomic axes— oral, pharyngeal, and laryngeal.170 Positioning the patient in the sniffing position approximates this alignment. Cervical flexion aligns the pharyngeal and laryngeal axes, and maximal head extension at the atlantooccipital joint brings the oral axis closer into alignment (p 1666)
Sniffing position: Requires 35 degrees of cervical flexion, which is accomplished by a 7- to 9-cm elevation of the head on a firm cushion
Assessment of a patient’s ability to assume this position should be included in the airway examination; an inability to extend the neck at the atlantooccipital joint is associated with difficult laryngoscopy (p. 1653).
Obesity and Sniffing Position
Patients who are obese often require elevation of the shoulders and upper back to achieve adequate cervical flexion, which can be accomplished by placing the patient in the ramped position using either a specialized device, such as the Troop Elevation Pillow (Mercury Medical, Clearwater, FL) or folded blankets. Confirming horizontal alignment of the external auditory meatus with the sternal notch is useful for ensuring optimal head elevation in both obese and nonobese patients (p.1666)
Mouth Opening
Mouth opening is best achieved using the scissors technique; the right thumb pushes caudally on the right lower molars while the index or third finger of the right hand pushes on the right upper molars in the opposite direction (p. 1667)
Laryngeal Mask Airway (LMA)
A supraglottic airway device “perilaryngeal sealer” Multipurpose: primary airway management device a rescue airway device conduit for endotracheal intubation. Appropriate Size is based on patient weight Adult sizes 30-50 Kg LMA 3 50-70 Kg LMA 4 70-100 Kg LMA 5 >100 Kg LMA 6
cLMA The Original Version
The original version, the LMA Classic (cLMA), consists of an oval-shaped, silicone mask with an inflatable cuff that sits in the hypopharynx and forms a seal around the periglottic tissues (Figure 55-14). An air- way tube attached to the mask exits the mouth and has a standard 15-mm connector for attachment to an anesthesia circuit or to a bag-valve device. The seal around the laryngeal inlet allows for the delivery of oxygen and inhaled anesthetics during spontaneous ventilation and permits PPV at pressures up to 20 cm H2O. The cLMA is reusable up to 40 times and is available in a variety of sizes from size 1 (neonate) to size 6 (large adult, >100 kg).
Classic VS. Supreme LMA
LMA Supreme has a modified cuff design, a drain- age tube that allows for gastric access, and an integrated bite block.
Supreme and ProSeal: PPV at pressures up to 30 cm H2O.
Alternative you may see: i-gel- Cuffless anatomically preshaped sealers do not have a cuff; rather, they provide an airway seal by their anatomically preshaped design.
Cuffed pharyngeal tubes- like Combitube and King airway- more common in pre-hospital/ EMS- not frequently used in anesthesia
LMA Insertion
Equipment-
20 or 50 cc syringe,
lubricant, suction, stethoscope, tape, soft bite block
Adequate depth of anesthesia is critical for successful insertion
Deflate cuff (+/-), lubricate posterior aspect
After insertion, inflate with minimum effective volume of air
target cuff pressure of 40 to 60 cm H2O
Confirmation: gentle PPV, capnography, and auscultation
leak audible at inspiratory pressure ~18 to 20 cm H2O
Insertion of LMA
The tip of the cuff is pressed upward against the hard palate by the index finger while the middle finger opens the mouth. B, The LMA is pressed backward in a smooth movement. The nondominant hand is used to extend the head. C, The LMA is advanced until definite resistance is felt. D, Before the index finger is removed, the nondominant hand presses down on the LMA to prevent dislodgment during removal of the index finger. The cuff is subsequently inflated.
LMA Proper Fit
To achieve a proper fit, the manufacturer of the LMA suggests placing the largest size LMA possible; an airtight seal is achieved more frequently with a size 5 LMA in the average adult man and a size 4 LMA in the average adult woman.144 Using too small of an LMA can result in over inflation of the cuff to achieve a seal, which can predispose the patient to oropharyngolaryngeal morbidity and nerve damage.145 Larger sizes, however, may be associated with a more frequent incidence of sore throat; therefore a smaller size may be appropriate when spontaneous ventilation through the LMA is planned.
LMA Advantages
Increased speed and ease of placement by inexperienced personnel
improved hemodynamic stability at induction and during emergence
reduced anesthetic requirements for airway tolerance
lower frequency of coughing during emergence
lower incidence of sore throats in adults (10% vs 30%)
avoids “foreign body” in the trachea
LMA Disadvantages
NOT a definitive AW
lower seal pressure
inability to use mechanical ventilation* (at higher peak pressures)
higher frequency of gastric insufflation
does not maximally protect against aspiration
no protection against laryngospasm
Monitored Anesthesia Care
Complete Airway Setup Ready to go
Nasal Cannula- EVERYONE GETS O2
Spontaneously Breathing Patient
Nasal airway if snoring (partially obstructed breathing).
General Anesthesia Mask Case
Use when:
Difficult airway not present
Surgeon does not need access to head/neck
No airway bleeding/secretions
Case of short duration
No table position changes- head available
Obstruction easily relieved with oral nasal airway/ chin lift
Patient will spontaneously breathe-no neuromuscular blocker used
General Anesthesia LMA Case
Use when: Difficult airway not present Surgeon does not need access to head/neck (?) No airway bleeding/secretions Case of short duration More reliable patent airway than mask Want hands free
General Anesthesia Tracheal Intubation
Use when: Airway compromise Airway inaccessible Long surgical time Alternate surgical positions Surgery of head, neck, check, or abdomen Need for controlled ventilation and/or positive end-expiratory pressure Inability to maintain airway with mask/LMA Aspiration risk Airway/ lung disease Surgery requires muscle relaxation
The pharyngeal musculature in the awake patient helps
maintain airway patency; loss of pharyngeal muscle tone is one of the primary causes of upper airway obstruction during anesthesia
The oropharynx begins at? Extends?
the soft palate and inferiorly extends to the level of the epiglottis. The lateral walls contain the palatoglossal folds and the palatopharyngeal folds, also termed the anterior and posterior faucial (tonsillar) pillars, respectively; these folds contain the palatine tonsils, which can hypertrophy and cause airway obstruction (Figure 55-4). The base of the tongue lies in the anterior aspect of the oropharynx, connected to the epiglottis by the glossoepiglottic folds, which bound paired spaces known as the valleculae (although these are frequently referred to as a single space called the vallecula).
