Hypoxia

Question 1

Describe and explain pathophysiological changes that may lead to global or regional poor transport of oxygen from the air to airways

Answer 1

Muscle chest wall problems - scoliosis, kyphosis, trauma
Neural problems - respiratory centre depression, muscle weakness
Stiff lungs - severe fibrosis, COPD, severe asthma
Severe airways obstruction

Question 2

Describe and explain pathophysiological changes that may lead to poor oxygen transport from the alveolar gas to the pulmonary capillaries

Answer 2

Ventilation/perfusion mismatch - alveoli poorly ventilated (pneumonia, acute asthma, RDS of newborn), alveoli poorly perfused (pulmonary embolism)
Diffusion defect of alveolar membrane - fibrosis (fibrosing alveolitis, asbestosis, pneumoconiosis), pulmonary oedema, emphysema

Question 3

Describe and explain pathophysiological changes that may lead to global or regional poor transport of oxygen from the arterial blood to regional arteries

Answer 3

Shock - hypovolaemic, cardiogenic, mechanical, septic, anaphylactic

Question 4

Describe and explain the pathophysiological changes with an arterial blood problem

Answer 4

Anaemia

Question 5

Describe and explain the pathophysiological changes that may lead to a problem in the regional arteries

Answer 5

Peripheral artery disease - atheroma/embolism –> arterial narrowing/occlusion

Question 6

Explain how oxygenation may be measured

Answer 6

Oxygen saturation of Hb in arterial blood (SaO2) - using pulse oximetry
Arterial blood gas analysis - from radial artery

Question 7

Describe the steps in the transport of oxygen from the atmosphere to the tissues of the body

Answer 7

Air–> airways –> alveolar gas –> arterial blood –> regional arteries –> capillary blood –> tissues