Question

Ventilation-perfusion mismatch. Please explain in your own words, the importance of or relevance of the V/Q parameter. Please highlight its importance as a mathematical parameter in our mass transport models as well as its implications to clinical performance and pathologies. Max of 400 words.

Answer 1

A imbalance between ventilation (a cycle of inhalation and exhalation) and perfusion (the passage of blood through the alveoli of lungs) is called ventilation- perfusion (P/Q) mismatch. It generally occurs in case of hypoxemia and respiratory failure.

The normal ideal ventilation perfusion ratio is approximately1.05. V/Q can be assessed in the lung as a whole, or in individual. Depending on the position within the lungs, the values of V/Q changes.

Decreased V/Q value represent impaired pulmonary gas exchange and a low arterial partial pressure of oxygen (paO₂), amd impaired excretion of carbon dioxide is can also be observed. A rise in the arterial partial pressure of carbon dioxide (paCO₂)does not occur generally because the paCO₂ reaches normal due to increased respiration rate. These observations can be seen in chronic bronchitis, asthma, hepatopulmonary syndrome, and acute pulmonary edema.