Lesser forms of V/Q mismatching occur when all areas of the lung still receive ventilation and perfusion but their distributions do not coincide, causing a regional imbalance.

The main problem resulting from this is inadequate oxygenation of blood flowing through areas of low V/Q, leading to arterial hypoxaemia.

General anaesthesia almost inevitably produces some degree of V/Q mismatching.

Question: Will increasing the inspired oxygen concentration correct the arterial hypoxaemia in this situation?

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Lesser forms of V/Q mismatching occur when all areas of the lung still receive ventilation and perfusion but their distributions do not coincide, causing a regional imbalance.

The main problem resulting from this is inadequate oxygenation of blood flowing through areas of low V/Q, leading to arterial hypoxaemia.

General anaesthesia almost inevitably produces some degree of V/Q mismatching.

Question: Will increasing the inspired oxygen concentration correct the arterial hypoxaemia in this situation?

Answer: Yes, because the area of low V/Q still has some ventilation, and by using a higher inspired oxygen concentration there will be sufficient reaching this area to oxygenate the blood adequately. This is the main reason why a raised inspired oxygen concentration is routinely used in anaesthesia.