9. Respiratory Failure Flashcards
What are the steps in the oxygen transport pathway from air to tissues?
Air, airways, alveolar gas, alveolar membrane, arterial blood, regional arteries, capillary blood, tissues.
How can disease processes affect oxygen transport through air?
High altitude means low inspired oxygen.
How can disease processes affect oxygen transport as air moves in the airways?
Scolioses/kyphosis, trauma, myasthenia gravis, muscular dystrophy cause muscle chest wall problems so air can’t enter airways.
How can disease processes affect oxygen transport through airways?
Obstructive airway disease like asthma or COPD.
How can disease processes affect oxygen transport through alveolar membranes?
Fibrosis from silicosis or alveolitis.
How can disease processes affect oxygen transport through alveolar membrane to arterial blood transfer?
- Pulmonary oedema from cardiogenic causes, aspiration, infection, or trauma.
- Ventilation perfusion mismatching from pulmonary embolism, pneumonia, consolidation, collapse of lobe, large airway obstruction.
How can disease processes affect oxygen transport through arterial blood?
Anaemia from insufficient red cells produced in marrow, deficiency of B12/ iron, or CO binding.
How can disease processes affect oxygen transport through arterial blood delivering to regional arteries?
Shock from global poor perfusion.
How can disease processes affect oxygen transport through regional arteries?
Peripheral arterial disease from local arterial insufficiency or damage to individual tissues.
What is type I respiratory failure?
pO2 of arterial blood low but pCO2 is normal or even low.
What is type II respiratory failure?
pO2 of arterial blood low, pCO2 is high.
What are the acute effects of respiratory failure?
Breathlessness.
What causes breathlessness in respiratory failure?
Increased CO2 and decreased O2 is detected by central chemoreceptors, so breathlessness gives some compensation.
What are the chronic effects of respiratory failure?
CO2 retention, right heart failure.
How does CO2 retention cause hypoxia?
CSF acidity correct by choroid plexus, initial acidosis corrected by kidneys. Reduced respiratory drive so hypoxia.
