Question

1. Patient A has a dead space volume of 150ml, a tidal volume of 450ml and a respiratory frequency of 10. Patient B has a dead space volume of 150ml, a tidal volume of 300ml and a respiratory frequency of 15.

1. Which patient has the most effective ventilation?

2. Why?

Answer 1

Patient A has the most effective ventilation.

This is because , an increase in the tidal volume results in increase in the the ventilation. In a normal healthy person tidal volume is approximately 500 ml per inspiration. Patient A has tidal volume of 450 ml which is approximately normal.

Tidal volume is the amount of air that moves in and out of the lungs in each respiratory cycle. When tidal volume increases ,respiratory rate increases and the depth of respiration also increases. This results in taking more oxygen into the body and removing more carbon dioxide from the body. This give rise to effective ventilation.

Patient A - respiratory frequency is also within a normal level. Normal value is 8-16 breaths per minute.

A person who has normal respiratory rate with a large tidal volume would have efficient gas exchange because the ratio of dead space to tidal volume will be low.

Therefore the patient A has effective ventilation.