AIRWAY ALGORITHMS FOR THE EMERGENCY DEPARTMENT

Classification of Decision Pathways

Evaluation of the Patient

Optimizing Procedure Success

Begin Airway Algorithms

· Crash Airway Algorithm

· Difficult Airway Algorithm

· Rapid Sequence Intubation

· Failed Airway Algorithm

Sources

About This Document

Indications for Intubation:

1. Failure of airway maintenance (airway obstructs without external aids) or positioning (loss of gag or swallow reflexes).

2. Failure of oxygenation.

3. Failure of ventilation with CO2 retention and acidosis.

4. Anticipated course of illness will require intervention, or transport mandates a predictable secured airway.

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Classification of Decision Pathways:

Most airway decisions in the ED involve urgent events requiring an immediate attempt at intubation and cannot be avoided. Occasionally, however, there is time for evaluation. Several initial decisions must be made:

1. Is there time for evaluation? If not, intubation must be achieved by any means possible despite unanticipated problems. This decision path follows the CRASH AIRWAY ALGORITHM.

2. If there is time for evaluation, a decision must be made as to whether there will be difficulties gaining airway access. If so, the decision path follows the DIFFICULT AIRWAY ALGORITHM.

3. If there is no finding to suggest a difficult airway, the remaining patients can be managed by straightforward RAPID SEQUENCE INTUBATION (RSI).

4. If any of these decision pathways fail to secure a subglottic airway via endotracheal tube after 3 optimal attempts at intubation, optimal mask ventilation , a supraglottic airway, such as a Laryngeal Mask Airway or Combitube must be applied to ensure adequate oxygenation and CO2 exchange. IF YOU CAN’T INTUBATE, VENTILATE.

5. If you can’t intubate and can’t ventilate, the decision path follows the FAILED AIRWAY ALGORITHM. Here one might attempt a supraglottic device such as a Laryngeal Mask Airway (LMA) while preparing for cricothyrotomy – or, in children under 12 years, transtracheal jet ventilation.

6. If you can’t intubate and can’t ventilate and are in an isolated area with insufficient help and cannot make yourself do a surgical cricothyrotomy, the patient will probably die without intervention. If you have a functioning LMA at this point, there is now some evidence that transport might be attempted with only the supraglottic device - especially in children.

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Evaluation of the Patient:

If time allows for evaluation of the patient prior to airway placement, there are 3 primary considerations:

1. Will intubation be difficult?

Teeth

· Maxillary teeth markedly overlap mandibular teeth. Laryngoscope blade is forced cephalad, making its effective length markedly shorter.

· Length of upper incisors long, forcing blade cephalad.

· Patient cannot force lower teeth anterior to upper teeth. TMJ is limited and jaw and tongue cannot come forward.

· Mouth will not open more than 3 cm. Normal is 5-6 cm. Flange of laryngoscope blade is 2 cm.

Pharynx

· If mouth is open and cannot see the uvula and tonsillar pillars, tongue is relatively large compared to other mouth structures.

· High arched palate suggests reduced oropharyngeal volume and reduced room for blade and tube.

Mandibular Space

· Thyro-mental distance less than 3 fingerbreadths. Normal is over 6 cm. If reduced, cords are more anterior, as they lie at the mid-point of the thyroid cartilage.

· Reduced compliance of mandibular space due to fibrosis, tumor or hematoma will not allow for displacement of tongue during intubation.

Neck

· Short neck implies and anterior larynx.

· Thick neck makes alignment for intubation difficult.

· Inability to attain sniffing position makes alignment difficult. Ideal flexion of neck is 35 degrees. Ideal extension at atlanto-occipital joint is 90 degrees.

2. Will bag mask ventilation be difficult?

· Mask seal must be effective. Beards, secretions or facial injury may be a barrier

· Obesity leads to both upper airway problems and need for high inflation pressures.

· Age over 55 leading to concurrent disease and reduced tissue elasticity.

· No teeth to provide a seat for both mask and tongue containment.

· Stiff lungs due to decreased pulmonary compliance as seen in asthma, fibrosis or COPD.

3. Will cricothyrotomy be difficult?

· History of neck surgery

· Presence of hematoma

· Obesity

· Radiation to neck

· Trauma to neck

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Optimizing Procedure Success:

1. Optimal Mask Ventilation

· Two people to apply mask. One implements jaw thrust and one applies mask seal.

· Adequately sized oropharyngeal airway.

· Nasal vasoconstrictor, lubrication and 2 adequately sized nasopharyngeal airways.

· Watch for inflation of stomach.

2. Optimal Attempted Intubation

· Ideally 3 attempts at intubation should be maximum. Additional attempts will increase supraglottic and glottic trauma leading to swelling and more problems.

· The most experienced person should make the last attempt.

· There should be adequate paralysis.

· Positioning of the patient should be optimal.

· Pressure should be applied to the thyroid cartilage (not the cricoid, which is compressed to prevent aspiration).

· Different blades can be tried. The Miller blade will allow lifting of the epiglottis.

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Sources:

Adapted from:

Walls RM, Murphy MF. The difficult airway in adults. UpToDate 2008 ver.15.3. [CDROM].

References:

1. Trevisanuto D, Verghese C, Doglioni N, Ferrarese P, Zanardo V. Laryngeal mask airway for inter-hospital transport of neonates. Pediatrics 2005;115:e109–e111. URL: http://pediatrics.aappublications.org/cgi/reprint/peds.2004-1468v1

2. Martin SE, Ochsner MG, Jarman RH, Agudelo WE, Davis FE. Use of the laryngeal mask airway in air transport when intubation fails. J Trauma. 1999 Aug;47(2):352-7.

3. Walls R, Murphy MF. The failed airway in adults. UpToDate 2008 ver.15.3 [CD ROM].

4. Walls RM. Manual of Emergency Airway Management 2004. Lippincot, Williams and Wilkins.

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