Hypoventilation

Inadequate alveolar ventilation resulting in insufficient respiratory gas exchange, leading to hypercapnia (PaCO₂ >6.0 kPa or >45 mmHg) with or without hypoxemia (PaO₂ <10.6 kPa or <80 mmHg), and causing respiratory acidosis.

Causes

• Medications

  • Opioids

  • Sedatives

  • General anesthetics

  • Other central nervous system depressants

  • Alcohol intoxication

• Obesity hypoventilation syndrome

• Neuromuscular causes

  • Muscular dystrophy

  • Amyotrophic lateral sclerosis (ALS)

  • Myasthenia gravis

  • Guillain–Barré syndrome

  • Spinal muscular atrophy

  • Phrenic nerve dysfunction

• Central nervous system causes

  • Head trauma

  • Brain tumor

  • Stroke

  • Congenital central hypoventilation syndrome (Ondine's curse)

  • Brainstem disorders affecting respiratory drive

• Pulmonary causes

  • Chronic obstructive pulmonary disease (COPD)

  • Obstructive sleep apnea

  • Severe asthma

  • Advanced pulmonary fibrosis

  • Airway obstruction

• Chest wall and respiratory mechanics

  • Scoliosis

  • Kyphoscoliosis

  • Flail chest

  • Rib fractures

  • Ankylosing spondylitis affecting the thoracic cage

• Other causes

  • Severe hypothyroidism

  • Respiratory muscle fatigue

  • Mechanical ventilation with inadequate minute ventilation

  • Critical illness affecting respiratory drive or muscle function