Sleep Related Breathing Disorders Flashcards
What does OSAS stand for
Obstructive sleep apnoea syndrome
What are some of the consequences of OSAS
Quality of life
daytime sleepiness
poor concentraiton
decreased cognitive function
OSAS is a risk factor for what 3 conditions
Cardiovascular disease
Stoke and hypertension
What might sleep aggrevate
Pre-existing respiratory disease and specific breathing disorders may arise during sleep
Where is the respiratory centre
In the medulla
Why does the respiratory centre become less responsive to chemical and mechanical stimuli during sleep
Because it receives less stimulation from higher cortical centres
What is really important in diseases associated with hypercapnic respiratory failure (COPD, neuromuscular disease and thoracic cage disorders)
The sleep related oxygen desaturation
What is the treatment for sleep related breathing disorders
To manage the underlying respiratory disease
Avoid aggravating factors (alcohol or sedative medication)
Is oxygen always beneficial and why?
It may alleviate oxygen desaturation but it may provoke further hypoventilation and carbon dioxide retention
How is long term ventilatory support given
As domiciliary nocturnal non invasive positive pressure ventilation
What triggers the ventilator to deliver additional tidal volume under positive pressure
The spontaneous respiratory efforts of the patient
What can control of nocturnal desaturation by NIPPV improve
Quality of sleep, nocturnal symtoms
Daytime symptoms
Gas exchange
What is a main cause of ventilatory failure
Kyphoscoliosis
What is OSAS
A condition of sleep related pharyngeal collapse in which recurrent episodes of upper airways occlusion occur during sleep causing diminution or cessation of airflow in the pharynx provoling arousals and sleep fragmentation resulting in daytime sleepiness
What plays an important role in maintaining the patency of the upper airway
The oropharyngeal dilator muscles
What plays an important role in maintaining patency of the upper airways
The oropharyngeal dilator muscles
What happens to the muscle tone during deep sleep
There is reduced muscle tone
What can result in narrowing of the upper airways
Fat deposition in the neck from obesity
bone morphology
soft tissue deposition (hypothyroidism
Enlargement of tonsils or adenoids in children
What can result in narrowing of the upper airways
Fat deposition in the neck from obesity
bone morphology
soft tissue deposition (hypothyroidism
Enlargement of tonsils or adenoids in children
How is apnoea terminated
By a brief arousal from sleep
What are some daytime symptoms of OSAS
Excessive sleepiness Poor concentration irritability morning headaches loss of libido
What type of scale is useful in assessing the likelihood of falling asleep in various situations
The Epworth sleepiness scale
Who do patients with OSAS have to advise
Driving licence authority
What might the bed partner report
Loud snoring
Witnessed apnoeas and restless sleep
What does examination focus on
Obesity
Increased neck circumference
anatomical abnormalities reducing pharyngeal calibre
nasal obstruction (polyps and deviated septum)
What are some of the CV complications of OSAS
Hypertension MI Stoke Cardiac arrhythmias Structural cardiac changes Cardiac failure
What is OSAS often associated with
Hormonal changes - reduced testoesterone and growth hormone levels
What does CPAP stand for
Continous positive airway pressure
What does definitive assessment of OSAS require
Polysomnography
What all is measured during a polysomnography
EEG - the stage of sleep EOG - Detects rapid eye movement Thermistor - airflow at the nose and mouth and ribcage and abdominal Oximetry - oxygen desaturation ECG - heart rate
When is OSAS usually diagnosed
When there are more than 15 apnoeas or hypopnoeas per hour, each lasting 10 second
What is an important treatment for patients who are overweight
Weight loss
What sleeping position should be discouraged
Sleeping on the back
What is now the first choice treatment for OSAS
Nasal CPAP applied via a tight fitting nasal mask
How does the CPAP work
It acts by splinting the pharyngeal airway open, counteracting the tendency to collapse
What pharmacological treatments are effective in OSAS
Moafinil
Protroptylline
Progesterone
Acetazolamide
What does uvulopalatopharyngoplasty involve
The surgical excision of redundant tissue of the soft palate, vuvla and pharyngeal walls
What is the purpose of uvulopalatopharyngoplasty
To increase the calibre of the pharyngeal airway
What happens in central sleep apnoea
Cessation of airflow at the nose and mouth which is associated with a lack of respiratory muscle activity
What happens in central sleep apnoea
Cessation of airflow at the nose and mouth which is associated with a lack of respiratory muscle activity
