Airway managementFrom PACT programPrepared by :Shaimaa Mohammed ICU

Contents:

Assessment of airway

Airway intervensions

Recognition of effective ventilation

The difficult airway:algorithms & adjuncts to management

Pitfalls in airway management

1) Assessment of the airway

Can be considered in 4 parts

Airway patecy :a partial or complete obstruction will compromise ventilation of the lungs and there for gas exchange

Protective reflexes :Help maintain patency and prevent aspiration

Respiratory drive :a patent and secure airway is of no value if gases is not being exchanged

Inspired oxygen concentration:Gas entering the pulmonary alveoli must have adequate oxygen concentration

Airway patency:

Airway obstruction is mostly due to:

Reduced muscle tone falling of the tongue backwards against the posterior pharyngeal wall

Adepressed level of consciousness is the greatest risk factor for airway obstruction(obtunded or anaesthetized)

Other causes for airway obstruction

Other causes of airway obstruction

ANECDOTEA 26 –year-old man arrived in the emergency department havingbeen in a house fire .His face and oral cavity showed heavydeposits of carbonaceous material .He was alert ,able to speak ina hours voice and was moderately tachypnic .Ten minutes later hecomplained difficulty breathing,had significant stridor and codentvocalize .After a further ten minutes he was drowsy ,obtundedand in severe respiratory distress .It was decided to intubate thepatient and this was achieced only in great difficulty due toalmost complete airway obstruction secondary to oedema andinflammation of the epiglottis and larynxcaused by thermal

injury.

Breathing difficulties in burn victims frequently require immediate tracheal intubationdue to rapidly developing airway/glottis oedema

Airway obstruction presentation:

Noisy breathing (on inspirationstridor

Poor expired airflow

Retraction of soft tissues

Increased respiratory distress

Paradoxical”rocking”movement of thorax

and abdomen)

If total obstructionNo sounds of breathing due to lack of airflow through the larynx

What is the difference between stridor and bronchospasm?

Stridor inspiratory noise due to partial upper airway obstruction

Bronchospasmpredominantlyexpiratory due to bronchial narrowing

Recognition of injuries to airway or other structures

Trauma to head and neck fractures or dislocation to the facial skeleton and mandible:

immediate disruption to the structures of the nose and oropharynx

later complications due to inflammation or soft tissue swelling and bleeding into the airway

Pulmonary aspiration of blood or dislodged teeth

Assessment of the airway should be repeated frequently during resuscitation of the trauma patient

Postoperative bleeding after operations to the neck(thyroid ,Carotid,larynx)

compression or displacement of the airway difficult intubation

Direct injury to the larynx ( rare) progressive hoarseness and SC emphysema

(Tracheal intubation make this situation worse ,require great care and skill)

!In assessing the airway ,always recognize the potential for cervical spine

injuries .Inadvertant movement of the cervical spine may occure during airwaymaneuvers (avoide or minimize)

THINK what risk factors for cervical spine instability can you identify?LinksCanadian C-Spine rule for radiography-ATLS

Recognition of anatomic variations /abnormalities(some can be detected by inspection some are only detectable by investigations)

Anatomical features suggest airway difficulty or difficult intubation:• Obesity• Maxillary prognathesia or prominent upper incisors• Short muscular neck and /or limited neck flexion or head extension(Reumatoide

arthritis-Ankylosing spondylitis)• Large breasts (In advanced pregnancy)• Acromegaly• High arched palate(Marfan Syndrome)• Oropharyngeal infections and tumours)• Cystic hygroma• Thyromental distance: From upper edge of the thyroid cartilage to the chin

with the head fully extended>7cmeasy intubation <6 cmmay predect difficult intubation

Inability to open mouth suggest s potential airway difficulty:

Masseter muscle spasm (dental abscess)

Temporo-mandibular joint dysfunction

Scarring-including post radiotherapy fibrosis

Reumatoide arthritis

Facial burns

Scleroderma

Trismus

Pier Robin syndrome :unusual small mandible ,posterior displacement or retraction of the tongue,upper airway obstruction,cleft palat in the maijority

Cervical immobility / abnormality might suggest a difficult intubation

Presence of Cervical collar

Ankylosing spondylitis as

Post radiotherapy fibrosis

Cervical haematoma (thyroid or anterior cervical surgery

Klippel-Feil abnormalities of the cervical spine

NB:

Buck teeth:upper incisors over the lower lip

Head and neck movement: Angle

formed between the positions of greatest extension and greatest flexion of the neck)

Jaw movement:

IGinterincisor gap

SLjaw sublaxation

IO > 5 cm or SLux > 0

IO < 5 cm or SLux = 0

IO < 5 cm or SLux < 0

All such assessments are useful but not foolproof.

When airway difficulty occurs un expectedly (urgent/emergency situation)use difficult airway algorithm

2)Protective reflexes:

To save guard a patent airway and to prevent aspiration

These reflexes depend on the prober functioning of the :

Epiglottis

False and true vocal cords

Sensory supply to the mucous membrane of the pharynx

What clinical situations /diagnoses are associated with partial or total loss of reflexes protecting patients from pulmonary aspiration?

4)Respiratory drive :

Controlled by the respiratoy center which acts to maintain PH(in the CSF)at 7.4

If CO2 increaseslower CSF PHStimulation of the respiratory driveincreased in minute volume (Feed back)

N.BThis may not occure if respiratory mechanics are disturbed

For assessing ventilatory function:

Clinically looking at the volume and frequency (Unreliable)

PCO2 measurement in blood gases

End tidal CO2

5)Inspired oxygen concentration:

The aim of airway managementproducing the maximal oxygen tension possible in the alveoli so high inspired oxygen concentrations are required

Identification of signs of hypoxaemia:

Central cyanosis(deoxy Hg of at least 5g/dl

Agitation ,confusion ,drowsiness

Signs of sympathetic over-activity and respiratory distress

If not corrected rapidlycardiac arrest ,irreversible cerebral injury,organdysfunction and death

N.Bpatient with significant anemia may never exhibit cyanosis while alive despite severe hypoxia (with a low total haemoglobin it may not be possible to have as much as 5 g/dl in the deoxygenated form

To Revise…..

1) Assessment of the airway

Can be considered in 4 parts

Airway patecy :a partial or complete obstruction will compromise ventilation of the lungs and there for gas exchange

Protective reflexes :Help maintain patency and prevent aspiration

Respiratory drive :a patent and secure airway is of no value if gases is not being exchanged

Inspired oxygen concentration:Gas entering the pulmonary alveoli must have adequate oxygen concentration