Hypoventilation

• Hypoventilation:

  • exists when the ratio of carbon dioxide production to alveolar ventilation increases above normal values
  • i.e. inadequate alveolar ventilation
• Hypoventilation can be Localised to particular lung lobe or segment:

  • Infection
  • sputum plug
  • atelectasis
• Hypoventilation can be Scattered throughout lung fields:

  • COPD
  • asthma
• Hypoventilation can be Generalised:

  • Pain
  • Reduced respiratory drive or consciousness
• How does hypoventilation affect pH?

  • Hypoventilation -> poor CO2 excretion
  • leads to increase of co2 concentration in alveoli
  • leads to increase of co2 concentration in arteriole blood
  • leads to increase of hydrogen ions
  • this decreases pH
  • which leads to respiratory acidosis