Airway Part 2 Flashcards
Factors that may indicate an anticipated difficult airway
Airway exam or previous difficult airway
Neck or mediastinal pathology
Upper airway impingement by mass
Previous surgery or radiation
Unstable neck fractures
Halo devices
Small or limited oral openings
Patients in the critical care setting
Techniques for awake intubation
Video or Fiberoptic-guided
Steps prior to awake intubation
Explanation - patient must be cooperative
Desiccation - Glycopyrolate
Dilation - prepare nasal airway, BOTH SIDES oxymetazoline 1-2 sprays each nostril
Dose of glyco for awake intubation
0.2 mg IV 5-20 minutes before procedure
Methods for anesthetizing patient’s airway
Topical and nerve blocks with preferably one agent to calculate max dose
Maximum safe dose of lidocaine
5 mg/kg
Three areas for airway anesthesia
Nasal
Posterior pharyngeal wall and base of tongue
Hypopharynx and trachea
Three nerves for airway block
Trigeminal
Glossopharyngeal
Vagus
Lidocaine application techniques
Spray from container
LA soaked in ribbon gauze
Cotton applicators
McKenzie technique
Mucosal atomization technique
Inhalation of nebulized lidocaine
“Spray as you go” via epidural catheter
Sedation techniques for awake intubation
Boluses of:
Diazepam, Midazolam, fentanyl, afentanyl, morphine, clonidine, procedex, propofol, ketamine
Combo of agents:
Benzos and opioids
IV infusions:
Propofol, remifentanil, preceded
Combo of IV infusions
Most common are precedex followed by remi
Precedex for awake airway management
Bolus 1 mcg/kg IV over 10 minutes, followed by infusion of 0.3-0.7 mcg/kg/hr.
Reduce in older adults and depressed cardiac function
Midaz dose
1-2 mg IV repeated prn
Fentanyl dose
25-200 mcg IV
Alfentanil dose
500-1500 mcg iv
Remifentanil dose
Bolus 0.5 mcg/kg IV followed by infusion of 0.1 mcg/kg/min
Propofol dose
0.25 mg/kg IV in intermittent boluses or Continuous infusion of 25-75 mcg/kg/min
Ketamine dose
0.2-0.8 mg/kg IV
Steps for Awake FOB intubation
Stay midline - keep scope midline as advance toward epiglottis
Visualize - airway structures of oropharyngeal, pharyngeal, and laryngeal spaces
Insufflate - o2 through suction port - oxygenates pt and keeps optics clear
Glottic Opening - Advance tip through glottic opening until tracheal rings come into view
Advance ETT
Verify placemtn by visualization of carina
When are rigid or semirigid fiberoptic stylets and laryngoscopes used?
Difficult airway situations such as trauma or limited mouth opening
When intubation has failed
During routine airway management - limited cervical spine mobility
Types of semirigid fiberoptic stylets
Shikani optical stylet
Levitan First pass Success Scope
Rigid Stylets
Bonfills Retromolar Intubation Fiberscope
Rigid Intubation fiberscope laryngoscope (RIFL)
Bullard laryngoscope
When is video laryngoscopy used
For anticipated difficult airways.
As a rescue strategy when unexpected difficulty
Advantages of Video Laryngoscopy
Magnification of airway
Visualization of structures that cannot be seen with DL
Other clinicians can also visualize airway
Recording capabilities
Disadvantages of Video Laryngoscopy
Cost
Blood and secretions can obscure view
Pharyngeal injuries
When do you start viewing the LCD monitor of the glidescope
As soon as the blade is past the teeth
Where does the glidescope blade get placed
In the vallecula
How is the ETT inserted with the glidescope
into the right side of the mouth by direct visualization and is advanced to the oropharynx
What stylet do you use with glidescope
Accompanying rigid stylet
Glidescope features
antifog
Recording capabilities
fiberoptic capabilities
Karl Storz C MAC video laryngoscope features
Similar to standard MAC
Less sharp anterior curve than Glide
Insertion and technique similar to DL
Antifog system
Recording
Fiberoptic capable
McGrath Video features
Portable
Modification of MAC blade
Similar to Glide - distal anterior angle, semirigid or rigid stylet recommended
No antifog system but uses hydrophilic optical surface coating to minimize condensation
Advantage of McGrath
Extremely portable
Channel Scope devices
Pentax Airway Scope
Res-Q-Scope
King Vision
Airtraq
Features of Channel scope devices
Allow for preloading of ETT
Can be used in limited spine mobility, prehospital setting, during difficult airway management
Less expensive option for video
Only airtraq has antifog
Head Elevation Laryngoscopy Position (HELP)
Aligns oral, pharyngeal, and laryngeal axes
Helpful with obese patients
Purpose and benefits of preoxygenation
Delays arterial desaturation prior to the induction of anesthesia and during subsequent apneic situations.
Increases o2 content and eliminated nitrogen (nitrogen is 79% of room air) from the FRC.
Gives 8 minutes of apneic time.
What does not preoxygenating do?
Decreases the time an anesthetist has to secure the airway
What do you look for when preoxygenating?
Movement of resp bag on machine.
Well defined ETCO2
Fraction of expired o2 to be 90% or greater before laryngoscopy*
How do you achieve preoxygenation?
100% inspired O2
Tight mask seal
Pt breathes at normal TV for 3-5 minutes
If limited time, can take 8 vital capacity breaths within 60 seconds
Minimum fresh gas flow of 5 L/min
THRIVE (transnasal humidified rapid-insufflation ventilatory exchange)
Used for preoxygenation
60L/min for 3 minutes
As effective as TV preoxygenation by face mask
Median apnea time 14 minutes
What law is used for apneic oxygenation
Boyle’s Law
O2 from oropharynx/nasopharynx diffuses down into alveoli as a result of net negative alveolar gas exchange rate during apnea
O2 can be insufflated at up to 15L/min with nasal cannula
NO DESAT
Goal of RSI
Achieve optimal intubating conditions rapidly to minimize length of time between LOC and securing of the airway with a cuffed ETT
Features of RSI
Cricoid pressure after preoxygenation and before IV induction.
No positive pressure ventilation after induction drugs and before intubation
Neuromuscular blocking agents
Modified RSI
Controlled PPV through cricoid pressure if necessary
Inspiratory pressure <20cm h2o
Cricoid Pressure/Sellick Maneuver
Posterior displacement of cricoid cartilage against cervical vertebrae with the patient in 20 degree head-up position
Goal of cricoid pressure
Prevent regurgitation and possible aspiration during induction.
When would you use cricoid pressure
Full stomach, bowel obstruction, poorly controlled GERD, nausea/vomiting
Optimal amount of force to occlude esophagus without obstruction of trachea
30 to 44 newtons
Apply 10-20 N (2kg force) prior to LOC then increase to 30-40 (4 kg) after LOC.
Hold until placement of tube is confirmed
Downsides to cricoid pressure
Efficacy is in question
Can interfere with visualization
Can induce relaxation of lower esophageal sphinctor
Esophagus can be lateral to cricoid ring
Holding during active vomiting may result in esophageal rupture
Where is the preferred place to secure the ett
Skin of maxilla - less mobility
Confirmation of correct placement of TT
Presence of a normal capnogram for at least 3 breaths is the most important and objective indicator
What cause cuase no EtCO2 tracing even with proper TT placement
Severe bronchospasm
Equipment malfunction
Cardiac arrest
Hemodynamic collapse
If in doubt, confirm with flexible bronch
Strategies for patent upper airway and effective ventilation
mask ventilation with appropriate mask seal w/ w/o jaw thrust.
Placement of an SAD such as LMA.
Placement of ETT into trachea
Placement of invasive airway such as cricothyrotomy tube
Indication of difficult facemask ventilation
Leaks from facemask and increasing use of O2 flush valve.
Poor chest rise.
Absent or inadequate breath sounds.
Gastric air entry.
Poor co2 return and altered waveform
O2 sat <92% by pulse ox when giving 100% inspired o2
Needing an oral airway or two-handed technique
Indications of difficult supraglottic airway placement
Requires multiple attempts or more than one airway practitioner
Leak pressure less than 10-15 cm H2o and a poor expired tidal volume
Leaks
Poor chest rise
Absent/inadequate breath sounds
Gastric air entry
Poor co2 return
Sat <92%
indications of difficult laryngoscopy and tracheal intubation
Inability to visualize any portion of vocal cords aka Cormack Lehane grade 3 or 4 after multiple attempts using a standard laryngoscope.
Requires multiple operators.
Failed intubation
Indications of difficulty with invasive airway device placement
Bleeding at site of insertion
Inability to identify correct anatomic structures
Trouble accessing cricothyroid membrane and puncturing through into the trachea
Complications of difficult airway
Death
Brain damage
Emergency surgical airway placement
Unanticipated ICU admission
What is the difficult airway algorithm
Guidelines that provide structure for decision making and tools for use when managing difficult airways
In anticipated and CICO situations
Any one of these factors alone may be clinically important enough to warrant an awake intubation
Suspected:
Difficult laryngoscopy
Difficult ventilation with face mask/supraglottic airway
Increased risk of aspiration
Increased risk of rapid desat
Difficult emergency invasive airway
If any one factor - intubation, ventilation, aspiration, desat risk - is “yes” what do you do
Proceed to intubation attempt with AWAKE intubation
If all factor in difficult airway algorithm are no, what do you do
Proceed to intubation after induction of general anesthesia
What is a priority to do through difficult airway algorithm
Optimize oxygenation throughout
What do you do if you cannot intubate, you’re in trouble, but you can still ventilate the patient
Wake the patient up
What do you do when you are suspicious of airway trouble
Intubate awake
Cricothyrotomy
Cricothyroid membrane is perforated to establish airflow to the trachea
CICO scenario
Needle vs Surgical
Needle cric
Not as secure
Can be used as backup if anatomy is not ideal for surgical (< 12 y/o)
18g, Ravussin needle, venous or arterial angiocath
Large bore catheter inserted through CTM in a caudad direction
What inflates lungs using a high-pressure oxygen source and a regulating valve to control o2 flow
Percutaneous transtracheal jet ventilation
PTJV
Concerns with PTJV
barotrauma, hyperinflation, incomplete exhalation of CO2
Avoid excessively large TV
Inspiratory pressure should remain <50 psi on regulator
I:E ratios 1:3 or 1:4
Obstruction of passive exhalation - place bilateral nasal airways or oral airway
Complications with PTJV
Barotrauma
Subq emphysema
Pneumothorax
Pneumomediastinum
Hypercarbia
Esophageal puncture
Airway mucosal damage
Blood or mucus obstruction
Catheter kinking
Inadvertant removal
Indications for a surgical cric
Failed airway - CICO
Traumatic injuries of maxillofacial, cervical spine, head, or neck structures that make intubation through the nose or mouth difficult to impossible or too time-consuming
Immediate relief of an upper airway obstruction
Need for a definitive airway for neck or facial surgery, assuming intubation is not possible
Absolute contraindications to surgical cric
Rare/none
Relative CI to surgical cric
Preexisting laryngeal or tracheal diseases - tumors, infections, abscesses in location
Distortion of neck anatomy - hematoma
Bleeding diathesis
History of coagulopathy
Equipment for surgical cric
No 10 scalpel
Bougie with a coude tip
Cuffed 6mm ETT
Serious complication of failure to do surgical cric early enough
Death
Brain damage
Reasons to extubate in the periop period
Minimize alterations in cardiopulmonary physiology
Decrease risk of resp infection and complications
Reduce length of stay = decreased costs and resource utilization
Extubation: Resp mechanics criteria
Vital capacity greater than 15 ml/kg
Max negative insp force greater than -20 cm h20
Adequate tidal volume of at least 4-5 ml/kg
Extubation: Indicators of ability to maintain adequate oxygenation with fio2 less than 50%
Spo2 greater than 90%
PaO2 greater than 60 mm Hg
Extubation: Indicator of ability to maintain adequate alveolar ventilation
PaCO2 less than 50 mm Hg
Standard extubation Global criteria
Hemodynamic status
Normothermia
Maintain patent airway
Adequate muscular strength
Acceptable metabolic indicators
Acceptable hematologic indicators
Adequate analgesia for optimal respiratory effort
Signs of ability to maintain patent airway
Return of laryngeal and cough reflexes
Appropriate level of consciousness
Indicators of adequate muscular strength
Reversal of a neuromuscular blockade as indicated by TOF ratio > 0.9, tetanic response to 100 hz for 5 seconds, double burst stimulation without fade
Head lift for more than 5 seconds with constant strong hand grip
Indicators or acceptable metabolic status
Electrolytes WNL
Acid-base balance WNL
Indicators of hematologic stability
Hemoglobin level consistent with adequate o2 delivery
Advantages of anesthetized extubation
Decreased CV stimulation
Decreased coughing and straining
Advantages of awake extubation
Return of airway reflexes
Decreased risk of aspiration
Airway reflex return
Spontaneous ventilation
Disadvantages of anesthetized extubation
Absent or obtunded airway reflexes
Increased risk of aspiration
Airway obstruction
Hypoventilation
Disadvantages of awake intubation
Increased CV stimulation
Increased coughing and straining
What plane of anesthesia should extubation be performed during
Surgical plane - Deeply anesthetized or stage 3
Fully awake
Techniques to attenuate increased CV stimulation
Beta blockers
Ca channel blockers
Vasodilators
Techniques to attenuate coughing and straining
Local anesthetics (IV, topical, intracuff lidocaine)
Opioids
Extubation of a difficult airway
Over a flexible FOB
Followed by placement of LMA
Use of an AEC
Leave ETT is place until extubation criteria are met
Complications of residual neuromuscular blockade
Upper airway obstruction from pharyngeal muscle
Hypoxemia
Increased risk of aspiration
Decreased ventilatory response to hypoxia
Unpleasant muscle weakness
Delay in tracheal extubation
Laryngospasm is caused by
Tensing of cords by cricothyroid muscles (stimulated by SLN nerve)
Adduction of cords by thyroarytenoid and lateral cricoarytenoid muscles (RLN)
Complications of laryngospasm
Bradycardia
Pulmonary edema
Pulmonary aspiration
Hypoxemia
Laryngospasm is caused by
Airway manipulation
Noxious stimuli, blood water mucus, within the pharynx
Stimulation of the larynx during inadequate anesthetic depth
Treatment for laryngospasm
Remove stimulus (suction space)
100% fio2
Open and clear airway (oral airway)
Jaw thrust - Larson maneuver or pressure on laryngospasm notch
PPV (10-30 cm h20)
Consider deeper anesthesia
Give succ (0.2-2 mg/kg Iv
Treatment of laryngotracheobronchitis
Humidified o2
Racemic epi
dexamethasone
helium-o2 mixture to facilitate o2 delivery through narrowed airways
Risk factors for dental trauma
Pre-existing dental pathology
One or more indicators of difficult laryngospasm and intubation
Sites most susceptible to mechanical injury
Posterior half of vocal cords
Arytenoids
Posterior tracheal wall
Development of aspiration pneumonia is dependent on
Type of aspirate
Volume of aspirate
Patient’s comorbidities
Phases of aspiration pneumonitis
1: Direct chemical injury
2: Inflammatory mediator release
Ways to decrease the acidity and volume of gastric contents
Antacids: sodium citrate 30ml, 20-30 minutes before induction
Histamine blockers: famotidine, ranitidine at least 45-60 min preop
PPI: omeprazole night before surgery
Gastroprokinetic: metoclopramide 20-30 minutes preop
Patient related risk factors for aspiration
Ascites
Cardiac arrest
Emergency surgery
Full stomach
N/V
Obesity
Scleroderma
Severe hypotension
Trauma or stress
Anesthesia related risk factors for aspiration
Cricoid pressure
Difficult airway management
Inadequate depth of anesthesia
Opioids
GI related risk for anesthesia
Decreased esoph sphincter tone
Diabetic gastroparesis
GERD
GI obstruction
Hiatal hernia
Increased gastric pressure
Peptic ulcer disease
Neurologic related risk for anesthesia
Decreased airway reflexes
Decreases LOC
Head injury
Seizures
Presentation of endobronchial intubation
Increased peak inspiratory pressures
Asymmetrical chest expansion
Unilateral breath sounds
Hypoxemia
Endotracheal tube complications
DOPE
Displacement
Obstruction
Pneumothorax
Equipment failure
