Ventilation-Perfusion Assignment Questions

1. How do changes in ventilation rate, cardiac output, and dead space ventilation affect alveolar PO2 and pulmonary venous PO2? Do these three factors have an additive effect towards increasing or decreasing total oxygen delivery to tissues. Explain.

Matlab files Vsensim and fdeadsens can be used as a guide for Qn #1

1. How can a change in mixed venous PO2 affect alveolar PO2 and total oxygen delivery to tissues?
2. Consider three different metabolic rates for an average person, viz., resting, active, maximal activity. How should the ventilation and perfusion rates change under each of these circumstances in order to ensure sufficient delivery of oxygen to the tissues? Would these rates also maintain sufficient saturation of blood in the pulmonary capillaries for each activity?
3. What happens to total oxygen delivery to tissues if there is a decrease in dead space ventilation? What other factor(s) could affect the oxygen delivery?
4. The Matlab file VQ3levsimrun systematically varies the ventilation and perfusion rates in the different lung segments. Explain what happens to the partial pressure of oxygen in the alveoli and the concentration of oxygen in the alveoli for the different lung segments in each case.   Explain how the oxygen concentrations at the left atrium (and in the systemic circuit) are affected by the variation in alveoli in different parts of the lung.