Airway Obstruction Flashcards
what determines the diameter of the airway
the cricoid cartilage is the only comlepte cartilaginous ring in the larynx, therefore it does
describe 4 special ENT features in children
large head
small nares
relatively large tongue
weak muscles and floppy head
how does the larynx differ in neonates
smaller and softer
higher - epiglottis rests at C1 (normally C3) and inferior margin of cricoid cartilage around C4
how does the subglottis differ in neonates
narrower - 3.5mm at cricoid
how does breathing differ in neonates
they are obligate nasal breathers
what is the equation for airflow resistance
AFR (proportional to) (1/r^4)
what is the significance of Poiseuille’s equation and Venturi effect in relation to airflow resistance in the airway
a tiny reduction in radius results in a significant increase in resistance and decrease in cross sectional area
this greatly increases the work of breathing
what are the consequences of neonates having floppy airways
can collapse and cause stridor or stretor
causes of airway obstruction
- Inflammatory/infective/allergy
- Tonsillar and adenoid enlargement
- Acute epiglottitis
- FB
- Physical compression/invasion of airway
- Trauma
- Neurological
- Neoplastic
- Burn
- Congenital airway pathology
signs/symptoms of airway obstruction
hypoxia, exertion related
- SOB on exertion or at rest
- Coughing
- Choking
- Inability to complete sentence
- Sternal/subcostal recession
- Tracheal tug
- Dusky skin colour
- Dysphagia
- Dysphonia
- Pyrexia
- Cyanosis
stridor
high pitched harsh noise due to turbulent airflow resulting from airway obstructions
stertor
low pitched sonorous sound arising from nasopharyngeal airway (heaving snoring/gasping)
recurrent respiratory papillomatosis
warty growths in the upper airway causing significant airway obstruction or voice change
aetiology of recurrent respiratory papillomatosis
caused by HPV, types 6 and 11 cause the majority of cases, and 16 and 18 have also been implicated
management of recurrent respiratory papillomatosis
extremely serious as it has the potential to destroy the whole of the larynx
extensive surgical management is required
age distribution of recurrent respiratory papillomatosis
bimodal - juvenile <12 and adult onset around the age of 40
subglottic stenosis
partial or complete narrowing of the subglottic area
aetiology of subglottic stenosis
rarely congenital
90% of cases are caused by endotracheal intubation - the duration of intubation is the most important factor in the development of stenosis
small vessel vasculitis
gastric acid reflux
how can small vessel vasculitis cause subglottic stenosis
can cause tracheal tissue damage and scarring
in which patients does gastric acid reflux cause subglottic stenosis
extremely overweight patients
ASSESSMENT of airway obstruction
appearance, skin circulation, work of breathing
ideally, how is respiratory failure managed
there is a progression from respiratory distress, to failure to arrest within a matter of minutes. The aim is to intervene before the development of respiratory distress
heliox
helium and oxygen
helium has a lower density than air, this means that there is a reduction in resistance to flow in airways and reduction in work of breathing
management of respiratory distress
ABCDE
oxygen, heliox
steroid
adrenaline
flexible fibre-optic endoscopy
secure airway with ET tube/tracheostomy
when should tracheostomy be performed
avoided at all possibilities as there is a significant risk of morbidity and mortality
