Basic Airway Management

Decide on the technique w/ back-up plan (A
Complete airway hx & PE
Ventilation challenges
Indications for intubation
Risks for aspiration
Risks of failed airway
Respiratory quotient (RQ) =
ratio of total CO2 production to O2 consumption
Normal VCO2 is
is 200 ml/min
Normal VO2 is
250 ml/min for resting awake adults, 3-4 ml/kg/min, and 6-7 ml/kg/min in children
So if you are struggling w/ the airway for 6 minutes, apnea, what is the Rate of rise of CO2:
6 mmHg during first minute
3-4 mmHg for each subsequent minute

60 Seconds: PaCO2 rise from 40 to 46 mmHg
120 Sec: 4649 mmHg
180 Sec: 49 53 mmHg
240 Sec: 53 57 mmHg
300 Sec: 57 61 mmHg
360 Sec: 61 65 mmHg

Hypoxemia
Anaerobic ventilation, H & lactate – acidosis
Cellular membranes in the brain and other hypoxia intolerant tissue beds begin to fail as ___ is consumed.
ATP
How much ATP is made with aerobic v. anaerobic respiration?
Aerobic- 38 mol ATP per 1 mol glucose. Anaerobic- 2 mol ATP per 1 mol glucose.
Organ specific responses to hypoxemia for heart
Initial
Excitatory & vasoconstrictive
HR, SV, contractility increase
Late
Depressed & vasodilatory
Blood pressure down, HR down, shock develops, fibrillation, asystole
Physical Exam Steps
DL worried about
aiway, small mouth, micrognathia, head/neck pathology, large toungue, high pallet, large teeth, obesity
Physical Exam Steps
mask ventilation worried about
airway, large tongue, endentulous or no teeth, obesity, OSA
Previous intubation questions
Does the pt know they were difficult?
Scar on their neck?
Sore throat, dental injury or lacerated lip?
does patient have Co-morbidities that increase probability such as?
Previous head & neck surgery/radiotherapy
RA, cervical disease, TMJ “locked jaw”
Uncontrolled DM
Genetic/congenital syndromes, such as Down syndrome,
Autoimmune dz
PEs lead to many false positives
Specificity 40-75%
how many difficult airways not predicted
25%
Using__ methods increases predictive value
≥ 2
Mallampati exam positioning is
Sitting upright
Tongue extended
No “ah”
Mallampati classes and scoring
PUSH
Class 1
Soft palate
Fauces
Uvula
Pillars
Class 2
Soft palate
Fauces
Uvula
Class 3
Soft palate
Base of uvula
Class 4
Hard palate only
Upper Lip Bite Test is Lower Incisors to
Class I
Vermillion border
Class II
Mid upper lip
Class III
Don’t touch upper lip
Wilson Risk Sum Score: 5 factors Predictive Factors
Weight
Head & neck movement
Mouth opening
Jaw development
Prominence of upper incisors
Wilson Risk score
one or two points for each mark hit:
weight 90, 110kg
h/n movement 90, <90 degrees jaw movement IG<5, slux 0; IG<5, slux <0 receding mandible moderate, severe protruding maxillary or buck teeth, moderate, severe Total of >3 = 75%, >4 predicts 90% difficult airway
Interincisor Gap aka
aka Mouth Opening
Opens mouth as wide as possible
Interincisor gap assessment
< two FB or 3 cm=difficult DL Miller NETT AFOI
Thyromental Distance or, Patil’s test, assessed by
Extend head
Distance from thyroid notch & submentum
Not hyomental which is 3cm
Thyromental Distance results mean
6.5cm easy, 6cm difficult, <6 very difficult/impossible
Head & Neck ROM assess by
Flexion-extension
< 90 ° = decreased ability to align axis including: Oral Pharyngeal Tracheal
CRNA Natl. Avg. does 880 cases/yr
Difficult mask: unable to keep O2Sat >90 in __%
Difficult Intubation: more than 3 attempts or more than 10 minutes in _%
Failed intubation in _%
0.07% Up to 5%,6-44/yr
1.1% Up to 8.5%,10-75/yr
0.01-0.03%, 1-3 in 10,000, every 5-11 yrs
Mask Ventilation steps
Right size- Over nose first, Base midway between lip & mental prominence

Head at xiphoid process

Sniffing position

C index & thumb

E fingers- Bony prominences only. Avoid submandibular soft tissue

Pull to mask-don’t push

Difficult Mask Fit broad indicators
Bearded patients
Edentulous patients
Very large patients
Very small patients
Airway/facial anomalies
Difficult Mask Ventilation, DMV, 6 criteria
Age >55 yrs
Body mass index >26 kg/m2
Beard
Edentulous
History of snoring
OSA
2+ factors = high likelihood of DMV
Ltd. mandibular protrusion DMV & DTI
DMV Corrective Actions
Reposition mask
Reposition patient
Place oral airway
Place nasal airway
Still can’t ventilate
2nd nasal airway
Call for help
2 handed mask/
assistant ventilates
Still difficult=definition of DMV
Airway Adjuncts allow Air passage between tongue & posterior pharyngeal wall. Why is this important?
Loss of upper airway muscle tone in anesthetized patients allows tongue to fall back against posterior wall of pharynx.
Oral Airways Benefits
Maintains patent airway
Prevents patient from biting/occluding ET tube
Prevents patient from biting tongue
Allows path for suctioning pharynx
Allows placement of (OG) tube
Oral Airways Contraindications
Awake patient- stims gag
Intact airway reflexes
Inability to open mouth
Poor dentition
oral airway Sized by distance (mm) from flange to tip
Peds size?
adult size?
Landmarks used?
peds 3.5cm-11cm
adult 40mm-100mm, typical is S80, M90, L100

tragus to corner of mouth, Too short equals airway obstruction

Types of Oral Airways
Berman
Open channel

Guedel
Inner channel

Fiberoptic- Williams, Ovassapian, Berman Intubating Airway

Oral Airway Insertion
Insert airway about half way down or until you approach posterior pharynx, then gently turned 180 degrees.
oral airway limitations and Disadvantages
Disadvantages
Aspiration
Trauma & necrosis
May elicit laryngospasm & vomiting
Loss of teeth

Limitations
Anatomy of patient
Existing trauma & lesions
Intact reflexes
Awake pts can’t tolerate

Nasal Airways
Indications
Dilate nares prior to nasal intubation
Oral airway adjunct
Oral airway not appropriate
Lighter planes of anesthesia
Oral surgeries
Adult & pediatric
Adult 26-34 Fr
Peds 12-24 Fr
Nasal Airways Insertion Technique
Lubrication some use 4 % lidocaine jelly
Slow downward pressure parallel to nasal floor
Bevel facing the septum (Why?)
Laryngeal Mask Airway (LMA) Insertion is independent of
Mallampati class
In-line traction / Cervical collar
Cricoid pressure (+/-)
Proper LMA Positioning
Tip of cuff rests in inferior recess of hypopharynx above esophageal sphincter
Sides of cuff face into pyriform fossa
Upper borders rest against the base of the tongue
Aperture bar lies over the laryngeal inlet
lma is Face mask alternative for elective surgical procedures
Less than 2-3 hours
Short duration when intubation is not necessary
Does not protect the airway from the effects of regurgitation or aspiration. full stomachs are
Non-fasted
Pregnancy
Trauma or severe pain
Acute abdomen
Thoracic injury
Chronic opioid use
Autonomic neuropathy
LMA Insertion Prepare LMA by
Lubricate posterior surface prior to insertion
LMA Insertion
Induction
Sniffing position/jaw thrust
Standard insertion technique
Aim toward your umbilicus
May finger sweep tip
LMA PEARLS
Test the cuff before use
Don’t lubricate anterior surface of the mask
Only when adequate anesthetic depth obtained
Displace jaw out and up
Maintain adequate anesthetic depth during surgery
Don’t disturb patient during emergence
Prime pt for removal while awake
Keep the cuff inflated during LMA removal
ETT Indications
Not required for all GA
Not risk-free

Aspiration risk
Definitive airway
Routine GA
Procedures w/ abdominal insufflation
Need for PPV> 20 mm H2O
Impaired gas exchange
Neurologic impairment
Untoward surgical positioning
Prolonged surgical time >2Hr

Inflation Valve/Port
Connects to syringe
May leak
Attached syringe
Can damage valve
Can injure patient’s eye
May prevent excess volume/pressure build up
Pilot Balloon/Inflation Lumen
Indicates whether cuff is inflated or not
Does not measure cuff pressures
Fails if damaged, will not
Deflate
Inflate
Av. Tracheal diameter is ___ mm
21-27
how much air does ett cuff hold ___ ml average
2-10
Cuff pressure should not exceed___ cmH20
Cuff pressure should not exceed 20-25 cmH20
25-30 mmHg tracheal mucosa perfusion pressure
High Volume Low Pressure cuffs (HVLP)
also LPHV. good
Pressure dispersed over greater surface area
Implant tested to ensure nontoxicity
Marked I.T. or Z-79
ETT Features
Machine end standard 15 mm
Murphy eye allows for ventilation in case
beveled end of tube lies against tracheal mucosa.
Murphy hole lessens the risk of complete tube occlusion.
ETT Clinical Implications Resistance & work of breathing. Varies inversely with internal diameter, ID, r/t which physics law?
Pouseille’s Law
1 mm decrease increases WOB by 35 – 150%
Mendelson’s Syndrome
Inhalation of highly acidic or particulate aspirate
Gastric volume > 25cc
Gastric pH < 2.5
non airway methods to protect from aspiration
Gastrointestinal stimulants
Gastric acid secretion blockers
Antacids
Antiemetics
Rapid Sequence Induction (RSI)
Used for patients at risk for aspiration
Only when a difficult airway is not identified
It is a sequence of events planned to flow rapidly
Rapid Sequence Induction
Preoxygenation with 100% O2 for 4-5 min – insure nitrogen wash out
Vital capacity breaths can be used for
True RSI no anxiolytics or narcotics
Application of cricoid pressure
Successive IV administration of a hypnotic & muscle relaxant
No positive pressure mask ventilation
An endotracheal tube is inserted in the trachea
Esophagus should be occluded to prevent passive regurgitation of stomach contents w/ ___ lbs of downward pressure on cricoid cartilage
9 lbs
Nasal Intubation
awake?
asleep?
blind?
Awake Nasal- Difficult airway in a patient who will need post-op ventilation
Asleep Nasal- Elective procedure with surgical implications
Blind Nasal- SV patient, failed intubation, no DL
Most common is
asleep nasal intubation w/ direct visualization
Nasal Intubation Determine most patent nare
left preferable because of shape of nasal ET
Nasal Intubation
Induction
Lubricated nasal airways – 6.5-8.0 or 28-34 Fr
Sequentially place lubricated nasal airways to dilate & lubricate the nare
Insert ETT into nare (same as nasal airway) until tip is in pharynx above epiglottis
Nasal Intubation Contraindications
Intranasal abnormalities
Tumors, fractures, deviations
Extensive facial trauma
Basilar skull fracture
Coagulopathies
Cerebrospinal fluid leak
Confirming ETT Placement Auscultation
Auscultation
Apices equal volume
Axilla
Bilateral lung bases, equal volume & expansion
Epigastric area
Confirming ETT Placement
Expired CO2 (end-tidal)
Gold Standard
Palpate balloon cuff at sternal notch
Compress pilot balloon
Pulse oximetry
Humidification in the ETT