Disorders of Ventilation Definition Alveolar hypoventilation

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Disorders of Ventilation
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Definition

• Alveolar hypoventilation
• PaCO2? ?? ?? 50-80mmHg
• Cause
• Acute life-threatening condition - ARDS
• Chronic T.246-1 (Harrison)
• Alveolar hyperventilation
• PaCO2? ??
• Not synonymus with hyperpnia
• Hyperpnia PaCO2? ??? ????
• minute ventilation volume?
  ???? ?
• Cause T.246-2 (Harrison)

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Causes of chronic hypoventilation
Central Sleep apnea
Obstructive or variable sleep apnea
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Clinical Feature of hypoventilation
Chronic hypoxia
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Causes of hyperventilation
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Obstructive Sleep Apnea
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Definition

• Sleep apnea
• intermittent cessation of airflow at the nose and
  mouth during sleep
• at least 10 second duration
• Sleep apnea syndrome
• clinical disorder that arises from recurrent
  apneas during sleep
• Obstructive Sleep Apnea (OSA)
• occlusion of the upper airway usually at the
  level of the oropharynx
• Central Sleep Apnea (CSA)
• transient abolition of central drive to the
  ventilatory muscles

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OSA

• Obstructive Sleep Apnea
• Cessation of airflow for 10 seconds
• Usually associated with 4 oxygen desaturation
• Obstructive Sleep hypopnea
• Decrease of 3050 in airflow for 10 seconds
• May be associated with 4 oxygen desaturation

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Epidemiology

• Apnea-hypopnea index 5
• 24 of men, 9 of women
• Excessive daytime somnolence
• 16 of men, 22 of women
• AHI 5 associated with excessive daytime
  somnolence
• 4 of men, 2 of women

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Upper airway patency
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Risk factors

• Age 40-70yr
• Male
• Heredity familial aggregation
• Current smoker
• Obesity BMI, neck circumference, waist-to-hip
  ratio
• Nasal congestion
• Craniofacial and upper airway abnormalities
• Endocrine Hypothyroidism, Acromegaly

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Sequences
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Risk factor Symptom - Outcome
Demographic correlation Male Age 40-70yr Familial
aggregation Risk factor Established Body
habitus Overweight Central body fat Large
neck Craniofacial and upper airway
abn Suspected GeneticsAPOe4 allele Smoking Menop
ause Alcohol use before sleep Nasal
congestion Endocrine

• Outcome and
• co-mobidity
• Problem with
• daytime functioning
• Cardiovascular and
• cerebrovascular
• Diabetes and
• metabolic syndrome

OSA Symptom snoring nocturnal breathing
pauses choking, gasping unrefreshing sleep
excessive daytime sleepiness
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Significant Co-morbidities
Cardiovascular Complications
Neuro-cognitive Complications
HTN CAD Stroke CHF
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OSA and cardiovascular outcomes

• Sleep apnea is a risk factor for morbidity
  and mortality from cardiovascular causes and
  hypertension
• Treatment cannot alters cardiovascular
  outcomes and hypertension

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OSA and motor vehicle collision

• Threefold increase in the rate of motor vehicle
  collisions with sleep apnea
• The rates fall with treatment

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Suggestion of sleep apnea

• Snoring
• Witnessed apnea, gasping
• Obesity (esp. neck circumference)
• Hypertension
• Excessive daytime sleepness
• Family history
• Previous tonsillectomy
• Non-restorative sleep

AHI 5

OSA syndrome
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Differential diagnosis

• Simple snoring
• Insufficient sleep
• Circadian-rhythm abnormality
• Narcolepsy
• Periodic limb movement disorder

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Polysomnography
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Obstructive Sleep Apnea
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Obstructive Sleep Hypopnea
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Treatment
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Treatment
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Conservative treatment

• Lateral sleeping position
• Avoidance of alcohol or sedative medications
• Weight loss

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MRI Before and After Weight Reduction
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Nasal CPAP
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Continuous positive airway pressure

• Nasal CPAP

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Nasal dilator (external or internal)
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Mandible Advancing Device
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Tongue Retaining Device
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Continuous positive airway pressure

• Decrease somnolence
• Improve the quality of life
• Short-term compliance
• 50-80
• nasal congestion, rhinorrhea
• dry throat
• Puffy eye, eye irritation
• Dermtologic problems mask leaves marks on face
  (m/c)
• Air swallowing
• Long-term use
• AHI, severe sx, snoring

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Selection of Patients

• CPAP Treatment of Choice
• for moderate to severe
  OSA
• Surgery
• 1. underlying specific surgically correctable
  abnormality
• 2. unsuccessful to noninvasive treatment or
  have been rejected, desire surgery
  and enough to undergo procedure