Hypoxia Flashcards
What are the O2 and CO2 levels like in type 1 Respiratory failure
Low O2 but normal CO2
What are the O2 and CO2 levels like in type 2 respiratory failure
Low O2, high CO2
How can treating type 2 respiratory failure with oxygen make the condition worse
As oxygen is now controlling the respiratory drive, by giving oxygen you take away this drive giving hypoventilation. This means the CO2 is not removed worsening the high pCO2. It also removes the pulmonary constriction giving ventilation-perfusion mismatch
What is happening if the ventilation perfusion ratio is less then 1
Hypoventilation - not breathing enough giving low pO2 and high pCO2
What is happening if the ventilation perfusion ratio is greater than 1
Ventilation is greater than perfusion giving high pO2 and low pCO2
How does pulmonary embolism lead to ventilation perfusion mismatch
The blood is diverted from the affected to the unaffected alveoli. This affects the ratio as there is more perfusion than ventilation. This results in hyperventilation to compensate
What does hypercapnia result in
- Respiratory acidosis
- increased bicarb production in the kidneys
What is done to compensate hypoxaemia
- increased EPO in the kidneys
- increased 2,3-BPG
What type of respiratory failure is caused by hypoventilation
Type 2
Give some acute causes of hypoventilation
Drug overdose, infection with COPD, head injury
Give some chronic causes of hypoventilation
Kyphoscoliosis, COPD, lung fibrosis, spinal trauma
What are the effects of hypoxaemia
- cyanosis
- cor pulmonale
How does hypoxaemia result in cor pulmonale
Hypoxic vasoconstriction of the pulmonary vessels occur giving pulmonary hypertension. This leads to right heart failure caused by lung issues.
