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Airway Management

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

Slide 3

Global Assessment

• Assess underlying need for airway control

– Duration of intubation

– Permanent support

– Temporary support

Slide 4

Global Assessment

• Pathophysiology of the respiratory failure

– Hypoxic respiratory failure

– Hypercapnic respiratory failure

• Assessment

• Code status should be clarified prior to proceeding.

Slide 5

Global Assessment

• Oxygenation

– Respiratory rate and use of accessory muscles

– Amount of supplemental oxygen

– Pulse oximeter or arterial blood gas

Slide 6

Global Assessment

• Airway

– Anatomy

– Patency

– Airway device in place

Slide 7

Oxygen Delivery Devices(In order of degree of support)

• Nasal Cannula

• Face tent

• Ventimask

• Nonrebreather mask

Slide 8

Oxygen Delivery DevicesNoninvasive Positive Pressure

• CPAP is a continuous positive pressure

• BiPAP allows for an inspiratory and expiratory pressure to support and improve spontaneous ventilation

Slide 9

Oxygen Delivery DevicesNoninvasive Positive Pressure

• Consider when to intubation

• Patient status

• Device considerations:

– 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.

Slide 10

Degree of Respiratory Distress

• Respiratory pattern

• Need for artificial airway

• Pulse oximetry

• Arterial blood gas

Slide 11

Temporizing Measures

• Naloxone for narcotic overdose

– 40 mcg every minute up to 200 mcg

– 0.4 - 2 mg of naloxone is indicated in patients with respiratory arrest and history suggestive of narcotic overdose

– Caution in patients with history of narcotic dependence

– Naloxone drip can be titrated starting at half the bolus dose used to obtain an effect

Slide 12

Temporizing Measures

• Flumazenil for benzodiazepine overdose

• Artificial airway for upper airway obstruction in patients with oversedation

• 100% oxygen and maintenance of spontaneous ventilation in patients with pneumothorax

Slide 13

Oral/Nasal Airways

Slide 14

Indications for Intubation

• Depressed mental status

– Head trauma patients with GCS 8 or less is an indication for intubation

– Drug overdose patients may require 24 - 48 hours airway control.

• Upper airway edema

– Inhalation injuries

– Ludwig’s angina

– Epiglottitis

Slide 15

Underlying Lung Disease

• Chronic obstructive lung disease

• Pulmonary embolus

• Restrictive lung disease

Slide 16

Airway Anatomy - Difficult Intubation

• Length of upper incisors and overriding maxillary teeth

• Interincisor distance < 3 cm

• Thyromental distance < 7 cm

• Neck extension < 35 degrees

• Sternomental distance < 12.5 cm

• Narrow palate (less than three finger breaths)

• Mallampati score class III or IV

• Stiff joint syndrome

Erden V, et al. Brit J Anesth. 2003;91:159-160.

Prayer Sign

Slide 17

Mallampati Score

Class I: Uvula/tonsillar pillars visible

Class II: Tip of the 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

Slide 18

Comorbidities

• Potential for aspiration requires rapid sequence intubation with cricoid pressure

• Potential for hypotension

• Organ failure

Slide 19

Induction Agents

• Sodium Thiopental

– 3 - 5 mg/kg IV

• Etomidate

– 0.1 - 0.3 mg/kg IV

• Propofol

– 2 - 3 mg/kg IV

• Ketamine

– 1 - 4 mg/kg IV, 5 - 10 mg/kg IM

Slide 20

Neuromuscular Blockers

• Succinylcholine

– 1 - 2 mg/kg IV, 4 mg/kg IM

• Rocuronium

– 0.6 - 1.2 mg/kg

• Vecuronium

– 0.1 mg/kg

• Cisatricurium

– 0.2 mg/kg

Slide 21

Rapid Sequence Intubation

• Preoxygenate for three to five minutes prior to induction

• Crycoid pressure should be applied from prior to induction until confirmation of appropriate placement.

• Succinylcholine 1 - 2 mg/kg

• Rocuronium 1.2 mg/kg

• Avoid mask ventilation after induction.

Slide 22

Y BAG PEOPLE (Reference #6)

Slide 23

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.

Slide 24

Sniffing Position

Align oral, pharyngeal, and laryngeal axes tobring epiglottis and vocal cords into view.

Hirsch N, et al. Anesthesiology. 2000;93(5):1366.

Slide 25

Mask Ventilation

• Mask ventilation crucial in patients who are difficult to intubate

Slide 26

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 valeculaETT for Fastrach LMA

Pediatric uncuffed ETT

ETT for blind nasal

Standard ETT

Slide 27

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.

Slide 28

Confirmation of Placement

• Direct visualization

• Humidity fogging the endotracheal tube

• End tidal CO2 which is maintained after > 5 breaths

• Refill in 5 seconds

• Symmetrical chest wall movement

• Bilateral breath sounds

• Maintenance of oxygenation by pulse oximetry

• Absence of epigastric auscultation during ventilation

Slide 29

Additional Considerations

• Additional personnel and an experienced provider as backup

• Suction available

• No a muscle relaxant if difficult mask ventilation is demonstrated or expected

• Awake intubation should be considered

Slide 30

American Society of Anesthesiologistswww.asahq.org

Slide 31

Alternative Methods

• Blind nasal intubation

• Eschmann stylet

• Fiber optic bronchoscopic intubation

• Laryngeal mask airway

• Light wand

• Retrograde intubation

• Surgical tracheostomy

• Combitube

Slide 32

Eschman Stylet

• Use if Grade III view achieved

• Perform direct laryngoscopy

• Place Eschman where trachea is anticipated

• Feel tracheal rings against stiffness of stylet

• Thread 7.0 or 7.5 ETT over stylet with laryngoscope in place

Slide 33

Fiberoptic Scope

Fiberoptic Scope is used

• For bronchoscopy

• To thread an endotracheal tube into the trachea

• Via laryngeal mask airway in place

Slide 34

The Laryngeal Mask Airway (LMA)

Slide 35

LMA Placement

LMA Placement:

• Guide along the palate

• Position underneath the epiglottis, in front of the tracheal opening, with the tip in the esophagus

• FOB placement through LMA positions in front of tracheaMartin S, et al. J Trauma Injury, Infection

Crit Care. 1999;47(2):352-357.

Slide 36

The FastrachTM 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

Slide 37

The Light Wand

Light wand:

• Transillumination of trachea

• Minimal complication

Contraindications:

• tumors, trauma, or foreign bodies of upper airway

Slide 38

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

Wesler N, et al. Acta Anaes Scan. 2004;48(4):412-416.

Slide 39

Combitube

Use:

• Emergency airway

Confirmation of Ventilation:

• blind blue tube

• white (clear) tube with patent distal end

Slide 40

Combitube

Prevent airway edema/trauma:

• Changed to endotracheal tube (ETT) or tracheostomy

Problems:

• Located in esophagus

• Failed exchange attempt

Slide 41

Tracheostomy

• Surgical airway through the cervical trachea

• Risks

• Caution

Sharpe M, et al. Laryngoscope. 2003;113(3):530-536.

Case Studies

The following are case studies / review questions that can be used for review of this presentation

Cases Studies

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Review Questions

Slide 43

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?

Slide 44

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.

Slide 45

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?

Slide 46

Case Scenario #2 - Answer

• 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.

Slide 47

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?

Slide 48

Case Scenario #3 - Answer

• 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

Review Questions

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Cases Studies

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Review Questions

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Slide 51

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.