Airway Management

Airway Management in the Emergency Department and ICU Mehdi Khosravi, MD Pulmonary/CCM Fellow Giuditta Angelini, MD Assistant Professor Jonathan T. Ketzler, MD Associate Professor Douglas B. Coursin, MD Professor Departments of Anesthesiology & Medicine University of Wisconsin, Madison

Global Assessment
Assess underlying need for airway control
Duration of intubation
- Nasal intubation less advantageous for potentially prolonged ventilator requirements
Permanent support
- Underlying advanced intrinsic lung or neuromuscular disease
Temporary support
Anesthesia
Presence of reversible intrinsic lung or neuromuscular disease
Protection of the airway due to depressed mental status
Presence of reversible upper airway pathology
Patient care needs (e.g., transport, CT scan, etc.)
Significant comorbidities
Aspiration potential or increased respiratory secretions
Hemodynamic issues such as cardiac disease or sepsis
Renal or liver failure

Global Assessment
Pathophysiology of the respiratory failure
Hypoxic respiratory failure
- In case of hypoxic respiratory failure, different noninvasive oxygen delivery devices can be used.
- The severity of hypoxia and presence or absence of underlying disease (such as COPD) will dictate the device of choice.
Hypercapnic respiratory failure
- The noninvasive device of choice for hypercapnic respiratory failure is BIPAP.
Assessment of above mentioned patient characteristics in conjunction with the mechanism of respiratory distress leads the clinician to proper choice and duration of invasive or noninvasive options for airway management.
Code status should be clarified prior to proceeding.

Global Assessment
Oxygenation
Respiratory rate and use of accessory muscles
- Is the patient in respiratory distress?
Amount of supplemental oxygen
- What is the patient’s oxygen demand?
Pulse oximeter or arterial blood gas
- Is the patient physiologically capable of providing appropriate supply?
Airway
Anatomy
- Will this patient be difficult to intubate?
Patency
- Is there a reversible anatomical cause of respiratory failure as opposed to intrinsic lung dysfunction?
Airway device in place
- Is there a nasopharyngeal airway or combitube in place?

Oxygen Delivery Devices (In order of degree of support)
Nasal Cannula
4% increase in FiO 2 for each 1 L of flow (e.g., 4 L flow = 37% or 6 L flow = 45%)
Face tent
At most delivers 40% at 10-15 L flow
Ventimask
Small amount of rebreathing
8 L flow = 40%, 15 L flow = 60%
Nonrebreather mask
Attached reservoir bag allows 100% oxygen to enter mask with inlet/outlet ports to allow exhalation to escape - does not guarantee 100% delivery.

Oxygen Delivery Devices Noninvasive Positive Pressure
CPAP is a continuous positive pressure
Indicated in hypoxic respiratory failure and obstructive sleep apnea
BiPAP allows for an inspiratory and expiratory pressure to support and improve spontaneous ventilation
Mainly indicated in hypercapnic respiratory failure and obstructive sleep apnea
If use of noninvasive modes of ventilation does not result in improved ventilation or oxygenation in two to three hours, intubation should be considered
These devices can be used if following conditions are met:
Patient is cooperative with appropriate level of consciousness
Patient does not have increased respiratory secretions or aspiration potential
Concurrent enteral feeding is contraindicated.
Facilitates early extubation, especially in COPD patients
Some devices allow respiratory rate to be set.
Up to 10 L of oxygen can be delivered into the mask for 100% oxygen delivery.
Nasal or oral (full face) mask can be used; less aspiration potential with nasal.

Degree of Respiratory Distress
Respiratory pattern
Accessory muscle use is an indication of distress.
Rate > 30 can indicate need for more support by noninvasive positive pressure or intubation
Need for artificial airway
Tongue and epiglottis fall back against posterior pharyngeal wall
Nasopharyngeal airway better tolerated
Pulse oximetry
O 2 saturation less than 92% on 60 - 100% oxygen can suggest the need for intubation based on whether there is anything immediately reversible which could improve ventilation.
Arterial blood gas
pH < 7.3 can indicate need for more support by noninvasive positive pressure or intubation.

Temporizing Measures
Naloxone for narcotic overdose
40 mcg every minute up to 200 mcg with:
- 45 minutes to one hour duration of action
0.4 - 2 mg of naloxone is indicated in patients with respiratory arrest and history suggestive of narcotic overdose
- There is a potential for pulmonary edema, so large dose is reserved for known overdose and respiratory arrest
Caution in patients with history of narcotic dependence
Naloxone drip can be titrated starting at half the bolus dose used to obtain an effect
- Manufacturer recommended 2 mg in 500 ml of normal saline or D5 gives 0.004 mg/ml concentration

Temporizing Measures (cont'd)
Flumazenil for benzodiazepine overdose
0.2 mg every minute up to 1 mg
Caution in patients with history of benzodiazepine or alcohol dependence
Caution in patients with history of seizure disorder as it will decrease the seizure threshold
Artificial airway for upper airway obstruction in patients with oversedation
May be necessary in patients with sleep apnea despite judicious sedation
100% oxygen and maintenance of spontaneous ventilation in patients with pneumothorax
Washout of nitrogen may decrease size of pneumothorax
Positive pressure may cause conversion to tension pneumothorax

Oral/Nasal Airways

Indications for Intubation
Depressed mental status
Head trauma patients with GCS 8 or less is an indication for intubation
- Associated with increased intracranial pressure
- Associated with need for operative intervention
- Avoid hypoxemia and hypercarbia which can increase morbidity and mortality
Drug overdose patients may require 24 - 48 hours airway control.
Upper airway edema
Inhalation injuries
Ludwig’s angina
Epiglottitis

Underlying Lung Disease
Chronic obstructive lung disease
Application of controlled ventilation may interfere with complete exhalation, overdistend alveoli, and impair right heart and pulmonary venous return.
Pulmonary embolus
Pulmonary artery and right ventricle already have high pressure and dependent on preload
Application of controlled ventilation may deteriorate oxygenation and systemic pressure.
Restrictive lung disease
May require less than 6 cc/kg V t to prevent elevated intrapulmonary pressure
Application of positive pressure may result in barotrauma in addition to impaired preload.

Airway Anatomy Suggesting Difficult Intubation
Length of upper incisors and overriding maxillary teeth
Interincisor (between front teeth) distance < 3 cm (two finger tips)
Thyromental distance < 7 cm
tip of mandible to hyoid bone (three finger breaths)
Neck extension < 35 degrees
Sternomental distance < 12.5 cm
With the head fully extended and mouth closed
Narrow palate (less than three finger breaths)
Mallampati score class III or IV
Stiff joint syndrome
About one third of diabetics characterized by short stature, joint rigidity, and tight waxy skin
Positive prayer sign with an inability to oppose fingers
No sign is foolproof to indicate intubation difficulty
Erden V, et al. Brit J Anesth. 2003;91:159-160. Prayer Sign

Mallampati Score
Class I: Uvula/tonsillar pillars visible
Class II: Tip of uvula/pillars hidden by tongue
Class III: Only soft palate visible
Class IV: Only hard palate visible
Den Herder, et al. Laryngoscope. 2005;115(4):735-739.

Comorbidities
Potential for aspiration requires rapid sequence intubation with cricoid pressure
Clear liquids < 4 hours
Particulate or solids < 8 hours
Acute injury with sympathetic stimulation and diabetics may have prolonged gastric emptying time.
Potential for hypotension
Cardiac dysfunction, hypovolemia, and sepsis
May need to consider awake intubation with topical anesthesia (aerosolized lidocaine) as sedation may precipitate hemodynamic compromise and even arrest.
Organ failure
Renal and hepatic failure will limit medication used.
Potential for preexisting pulmonary edema and airway bleeding from manipulation

Induction Agents
Sodium Thiopental
3 - 5 mg/kg IV
Profound hypotension in patients with hypovolemia, histamine release, arteritis
Dose should be decreased in both renal and hepatic failure.
Etomidate
0.1 - 0.3 mg/kg IV
Lower dose range for elderly and hypovolemic patients
Hemodynamic stability, myoclonus
Caution should be exercised as even one dose causes adrenal suppression due to similar steroid hormone structure.
Unlikely to have prolonged effect in organ failure

Induction Agents (cont'd)
Propofol
2 - 3 mg/kg IV
Hypotension, especially in patients with systolic heart dysfunction, bradycardia, and even heart block
Unlikely to have prolonged effect in organ failure
Ketamine
1 - 4 mg/kg IV, 5 - 10 mg/kg IM
Stimulates sympathetic nervous system
Requires atropine due to stimulated salivation and midazolam for potential of dysphoria
Avoid in patients with loss of autoregulation and closed head injury

Neuromuscular Blockers
Succinylcholine
1 - 2 mg/kg IV, 4 mg/kg IM
Avoid in patients with malignant hyperthermia, > 24 hours out from burn or trauma injury, upper motor neuron injury, and preexisting hyperkalemia
Rocuronium
0.6 - 1.2 mg/kg, highest dose required for rapid sequence
Hemodynamically stable, 10% renal elimination
Vecuronium
0.1 mg/kg
Hemodynamically stable, 10% renal elimination
Cisatricurium
0.2 mg/kg
Mild histamine release, Hoffman degradation, not prolonged in renal or hepatic failure

Rapid Sequence Intubation
Preoxygenate for three to five minutes prior to induction
Wash out nitrogen to avoid premature desaturation during intubation.
Crycoid pressure should be applied from prior to induction until confirmation of appropriate placement.
Succinylcholine 1 - 2 mg/kg IV will achieve intubation conditions in 30 seconds; Rocuronium 1.2 mg/kg IV will achieve intubation conditions in 45 seconds.
Other muscle relaxants do not produce intubation conditions in less than 60 seconds.
Avoid mask ventilation after induction.
Potentially can inflate stomach
Use only if necessary to ensure appropriate oxygenation during prolonged intubation.

Y BAG PEOPLE (Reference #6)

Cricoid Pressure
Cricoid is circumferential cartilage
Pressure obstructs esophagus to prevent escape of gastric contents
Maintains airway patency
Koziol C, et al. AORN. 2000;72(6):1018-1030.

Sniffing Position Align oral, pharyngeal, and laryngeal axes to bring epiglottis and vocal cords into view. Hirsch N, et al. Anesthesiology. 2000;93(5):1366.

Mask Ventilation
Mask ventilation crucial, especially in patients who are difficult to intubate
Sniffing position with tight mask fit optimal
May require two hands
Mask ventilation crucial, especially in patients who are difficult to intubate
Sniffing position with tight mask fit optimal
May require two hands

Laryngoscope Blades and Endotracheal Tubes Miller blade: End of blade should be under epiglottis Mac blade: End of blade should be placed in front of epiglottis in valecula ETT for Fastrach LMA Pediatric uncuffed ETT ETT for blind nasal Standard ETT

Graded Views on Intubation Grade 1: Full glottis visible Grade 2: Only posterior commissure Grade 3: Only epiglottis Grade 4: No glottis structures are visible Yarnamoto K, et al. Anesthesiology. 1997;86(2):316.

Confirmation of Placement
Direct visualization
Humidity fogging the endotracheal tube
End tidal CO 2 which is maintained after > 5 breaths
Low cardiac output results in decreased delivery of CO 2
Refill in 5 seconds of self-inflating bulb at the end of the endotracheal tube
Symmetrical chest wall movement
Bilateral breath sounds
Maintenance of oxygenation by pulse oximetry
Absence of epigastric auscultation during ventilation

Additional Considerations
Always have additional personnel and an experienced provider as backup available for potential failed intubation
Always have suction available
Never give a muscle relaxant if difficult mask ventilation is demonstrated or expected
Awake intubation should be considered in the following:
If patient is so hemodynamically unstable that induction drugs cannot be tolerated (topicalize airway)
If patient has a history or an exam which suggests difficult mask ventilation and/or direct laryngoscopy

American Society of Anesthesiologists www.asahq.org

Alternative Methods
Blind nasal intubation
Bleeding may cause problems with subsequent attempts.
Contraindicated in patients with facial trauma due to cribiform plate disruption or CSF leak
Avoid in immune suppressed (i.e., bone marrow transplant)
Eschmann stylet
Fiber optic bronchoscopic intubation
Awake vs. asleep
Laryngeal mask airway
Allows ventilation while bridging to more definitive airway
Light wand
Retrograde intubation
Through cricothyrotomy
Surgical tracheostomy
Combitube

Eschman Stylet
Use especially if Grade III view achieved
Direct laryngoscopy is performed
Place Eschman where trachea is anticipated
May feel tracheal rings against stiffness of stylet
Thread 7.0 or 7.5 ETT over stylet with the laryngoscope still in place

Fiberoptic Scope
Essentially what is used to do a bronchoscopy
Can be used to thread an endotracheal tube into the trachea either while the patient is asleep or on an awake patient with a topicalized airway
Via laryngeal mask airway in place due to inability to intubate with DL:
Aintree (airway exchange catheter) can be threaded over the FOB to be placed into trachea upon visualization
Wire-guided airway exchange catheter can also be used with one more step

The Laryngeal Mask Airway (LMA)

LMA Placement
Guide the LMA along the palate
Eventual position should be underneath the epiglottis, in front of the tracheal opening, with the tip in the esophagus
FOB placement through LMA positions in front of trachea
Martin S, et al. J Trauma Injury, Infection Crit Care. 1999;47(2):352-357.

The Fastrach TM Laryngeal Mask Airway
Reinforced LMA allows for passage of ETT without visualization of trachea.
10% failure rate in experienced hands
20% failure rate in inexperienced

The Light Wand
Transillumination of trachea with light at distal end
Trachea not visualized directly
Should not be used with tumors, trauma, or foreign bodies of upper airway
Minimal complication except for mucosal bleed
10% failure rate on first attempt in experienced hands

Retrograde Intubation
Puncture of the cricothyroid membrane with retrograde passage of a wire to the trachea
Endotracheal tube guided endoscopically over the wire through the trachea
Catheter through the cricothyroid can be used for jet ventilation if necessary.
Wesler N, et al. Acta Anaes Scan. 2004;48(4):412-416.

Combitube
Emergency airway used mostly by paramedics and emergency physicians for failed endotracheal intubation
Ventilation confirmed through blind blue tube
Combitube is in the esophagus and salem sump can be placed through white tube
Ventilation confirmed through white (clear) tube with patent distal end
Combitube is in the trachea and salem sump should be placed outside of combitube into esophagus
Fiber optic exchange can be accomplished through combitube

Combitube (cont'd)
Should be changed to endotracheal tube (ETT) or tracheostomy to prevent progressive airway edema
If in esophagus, take down pharyngeal cuff and attempt direct laryngoscopy (DL) or fiber optic bronchoscope (FOB) placement around combitube
Failed exchange attempt can be solved with operative tracheostomy
Placement of combitube can produce significant airway trauma
Removal prior to DL or FOB should be done with caution after thorough airway evaluation
Cricoid pressure should be maintained and emergency tracheostomy equipment available

Tracheostomy
Surgical airway through the cervical trachea
Emergent procedure carries risk of bleeding due to proximity of innominate artery
Can be difficult and time consuming in emergent situations
Sharpe M, et al. Laryngoscope. 2003;113(3):530-536.

Case Scenario #1
The patient is 70 kg with a 20-year history of diabetes.
On exam, the patient has intercisor distance of 4 cm, thyromental distance is 8 cm, neck extension is 45 degrees, and mallampati score is 1.
Your staff wants to use thiopental and pancuronium.
Do you have any further questions for this patient or would you proceed with your staff?

Case Scenario #1 - Answer
A diabetic for 20 years needs assessment for stiff joint syndrome.
You should have the patient demonstrate the prayer sign.
If the patient is unable to oppose their fingers, you should not give pancuronium.
You may want to proceed with an LMA and FOB at your disposal.
If the patient has a history of gastroparesis, you may want to consider an awake FOB.

Case Scenario #2
43-year-old patient with HIV, likely PCP pneumonia who had been prophylaxed with dapsone
RR is 38, oxygen saturation is 90% on 100% NRB mask
The patient is on his way to get a CT scan.
Is it appropriate to proceed without intubation?

Dapsone will produce some degree of methemoglobinemia.
Therefore, some degree of desaturation may not be overcome.
The patient is in significant respiratory distress and will be confined in an area without easy access.
Intubation should be considered as an extra measure of safety, especially as this patient is likely to get worse.

Case Scenario #3
40-year-old, 182-kg man has a history of sleep apnea and systolic ejection fraction of 25%. He has a Strep pneumonia in his left lower lobe and progressive respiratory insufficiency.
He extends his neck to 50 degrees and has a mallampati score of 2.
Would you proceed with an awake FOB?

The patient’s airway anatomy is not suggestive of difficulty.
However, with supine position, subcutaneous tissue may impair your ability to visualize or ventilate.
Use of gravity, including a shoulder roll, extreme sniffing position, and reverse trendelenburg may be helpful with asleep DL.
Prudent to have some accessory equipment, including an LMA and FOB, for back up

References
Caplan RA, et al. Practice guidelines for management of the difficult airway. Anesthesiology. 1993;78:597-602.
Langeron O, et al. Predictors of difficult mask ventilation . Anesthesiology. 2000;92:1229-36.
Frerk CM, et al. Predicting difficult intubation. Anaesthesia. 1991;46:1005-08.
Tse JC, et al. Predicting difficult endotracheal intubation in surgical patients scheduled for general anesthesia . Anesthesia & Analgesia. 1995;81:254-8.
Benumof JL, et al. LMA and the ASA difficult airway algorithm. Anesthesiology. 1996;84:686-99.
Reynolds S, Heffner J. Airway management of the critically ill patient. Chest. 2005;127:1397-1412.

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Airway Management

by Andrew Ferguson on Feb 15, 2008

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Airway Management — Presentation Transcript