207 OSA And Chest Wall Flashcards
(24 cards)
What is the biggest risk factor for OSA?
Neck circumference
What is the Bernoulli effect?
Airflow velocity increases at the site of a stricture but as the velocity increases, pressure on the lateral wall decreases and the airway collapses
When would you see OSA in children?
When enlarged tonsils
What causes the arousal of a pt with OSA?
Increased arterial PCO2
Name 5 risk factors for OSA (including facial deformities)
8 listed
Enlarged tonsils Obesity DM2 Large overbite Micrognathia/retrognathia HTN High arched palate Metabolic syndrome
What investigations are performed to diagnose OSA?
Overnight oximetry tracing
Polysomnography
Epworth sleepiness score
When is OSA diagnosed?
When hypopnoea/apnoea >15 times per hour
What is the treatment of OSA?
Lifestyle changes
Treat underlying causes
CPAP
Where is the central control of ventilation?
Medulla
What are the 2 areas of the medulla which control ventilation?
Ventral respiratory group
Dorsal respiratory group
Where is the pre-Botzinger complex found? What is its function?
In the ventral respiratory group - hypothesized location of central respiratory rhythm pattern generation circuitry.
Pacemaker cells here which initiate spontaneous breathing
Which area of the medulla controls inspiration?
Dorsal respiratory group
Which area of the medulla controls expiration?
Ventral respiratory group
What are the 2 main theories of initiation of ventilation?
Group pacemaker hypothesis
Pre Botzinger complex as initiator of generation of ventilation
Which cells regulate the patterning of ventilation in the CNS?
Pontine respiratory group
What is the role of the pontine respiratory group?
Antagonises the apneustic centre which inhibits inhalation decreasing tidal volume and regulating breathing. i.e. inhibition of inhibitory neurones
What is the outcome of damage to the pontine respiratory group?
Apneusis - deep, gasping inspiration with a pause at full inspiration followed by a brief, insufficient release.
What is the pathway for voluntary control of breathing?
From cerebral cortices –> pyramidal tracts –> corticospinal tracts (i.e. bypassing brainstem)
What is the Hering breuer reflex?
Reflex which prevents overinflation of the lung mediated by pulmonary stretch receptors which decrease the breathing via vagus nerve
What are J receptors?
Receptors in alveoli which are juxtaposed to capillaries and respond to e.g. pulmonary oedema (i.e. fluid) and act via vagus to cause dyspnoea due to decreased oxygenation
What is ideal PaCO2?
5.3kPa
Where are peripheral chemoreceptors found?
Carotid bodies and aortic sinus
Where are central chemoreceptors found?
In medulla close to the respiratory centre
Where in the CNS is H+ able to affect the central chemoreceptors?
CSF- brain barrier - i.e. choroid plexus. H+ unable to cross BBB whereas HCo3- is able.
