Sleep Apnoea And Neuromuscular Respiratory Failure Flashcards
Describe sleep apnoea syndrome.
Recurrent episodes of airway obstruction leading to apnea during the night
(Obstruction is in the posterior pharynx)
What is OSAS associated with?
Heavy snoring Day time somnolence / sleepiness Day time lack of concentration Hypertension Increased risk of stroke Increased risk of heart disease
What are the 3 main pathophysiological factors which cause repeated closure of the upper airways leading to apnea?
Muscle relaxation
Narrow pharynx’
Obesity
What is the difference between apnea and hypapnea?
Apnea is when the obstruction lasts for at least 10 seconds
Hypapnea is when the obstruction is partial and incomplete
What tests are carried out in the diagnosis of OSAS?
Clinical history and examination
Epworth questionaire
Overnight sleep study: full polysomnography, pulse oximetry, limited sleep studies
In the diagnosis of OSAS, what is involved in the full polysomnography?
EEC, EMG, EOG,
orsonasal flow, thoracoabdominal flow,
audiovisual recording, body position and oximetry,
How is the severity of OSAS scored?
It is based on the desaturation rate/ apnoea hypoxia level
0-5 = normal 5-15 = mild 15-30 = moderate >30 = severe
What is the treatment for OSAS?
Treat the exacerbating factors I.e. loose weight, avoid alcohol, diagnose and treat underlying neurological or endocrine disease.
Continuous positive airway pressure (CPAP)
Mandibular repositioning splint
What are the clinical features of narcolepsy?
Cataplexy
Excessive day time somnolence
Hypnagogic hallucination
Sleep paralysis
What is the treatment for narcolepsy?
Modafinil (stimulant)
Clomipramine (for cataplexy)
Sodium oxybate
What are the pathological features of chronic ventilators failure?
Elevated PCO2 >6.0kPa
P02 < 8 kPa
Normal blood pH
Elevated bicarbonate
What are the causes of chronic ventilator failure?
Most common is COPD and obesity hypoventilation syndrome
Chest wall abnormalities I.e. kyphoscoliosis
Respiratory muscle weakness I.e. motor neurons disease or muscular dystrophy
What are the symptoms of chronic ventilator failure?
Breathlessness Orthopnoea Ankle swelling Morning headache Recurrent chest infection Disturbed sleep
In chronic ventilator failure, what is found on clinical examination?
It depends on the underlying disease
Paradoxical movement of abdomen wall in suspected neuromuscular disease
Ankle oedema in patient with hypoxia/cor pulmonale
What is the treatment for chronic ventilator failure?
Domicillary non invasive ventilation (biPAP) - higher pressure than CPAP
Oxygen therapy
Tracheostomy ventilation (rarely used now)
What is the normal sleeping hours/patterns for a;
1) 6 month?
2) 2 year old?
3) new born?
1) 14-16 hours with 1-2 daytime naps
2) 12 hours with 1 daytime nap
2) 16-18 hours, sleep/wake 3-4 hour cycles
How can you asses sleep in children?
Polysomnography Direct behavioral observation Time lapse video Movement sensor in cot mattress 02/c02 monitoring
What are causes of excessive sleepiness in children?
Insufficient sleep
Narcolepsy
Obstructive sleep apnoea syndrome
How can OSAS cause death in children?
Failure to thrive
Neurocognitive defects
Systemic hypertension
For pulmonale
What are the treatments for OSAS in children?
Adenotonsillectomy
Weight loss
CPAP
Avoid environmental tobacco smoke
What are respiratory disorders associated with sleep apnoea in children?
Chronic neonatal lung disease
Cystic fibrosis
Asthma
What are neurological disorders that are associated with sleep apnoea in children?
Cerebral palsy
Down’s syndrome
Prayer willi syndrome
Neuromuscular disease i.e. duchesses muscular dystrophy
what sleep pattern/condition if on in:
a) down syndrome
b) Cystic fibrosis
c) chronic neonatal lung disease
d) prader willi syndrome
a) OSAS
b) less REM sleep/more awakenings
c) hyperaemia during REM sleep
d) excessive daytime somnolenece, they may be hypertonic
what is the pathophysiology of chronic ventilatory failure?
Pa02 < 8kPa
PaC02 >6kPa
normal blood PH
elevated bicarbonate
what are the symptoms of chronic ventillatory failure?
dyspnoea orthopnoea morning headache recurrent chest infections ankle oedema disturbed sleep
on examination of chronic ventillatory failure, what would you look for in suspected neuromuscular disease?
paradoxical abdominal wall motion
how can chronic ventillatory failure cause ankle oedema?
chronic ventillatory failure due to hypoxic cor pulmonale causes hypertrophy of right ventricle resulting in inefficient pumping of the right heart so blood backs up in the systemic circulation.
what are the investigation carried out for chronic ventillatory failure?
Lung function:
- nasal sniff inspiratory pressure
- lying and standing vital capacity
Assessment of hypoventilation:
- early morning ABG
- overnight oximetry
- transcutaneous C02 monitoring
- fluoroscopic screening of diaphragm
