An individual with early lung disease has a tidal volume of 500 mL.What is the alveolar volume if the dead space doubles and the tidal volume remains the same? (Assume that the normal ratio of dead space ventilation per minute to tidal volume [V_D/V_T] = 0.25.)

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Quizplus · Accepted Answer

With a normal dead space to tidal volume ratio of 0.25, the dead space volume (VD) for a tidal volume (VT) of 500 mL is 125 mL (0.25 * 500 mL). If the dead space doubles, it becomes 250 mL. The alveolar volume (VA) is the portion of the tidal volume that reaches the alveoli and participates in gas exchange. It can be calculated as VA = VT - VD. With the doubled dead space, VA = 500 mL - 250 mL = 250 mL.

An Individual with Early Lung Disease Has a Tidal Volume