What is the predicted change in tidal volume by adding 6 in of tubing to a ventilator circuit?

a. Decrease of 50 to 70 ml
b. Decrease of 30 to 50 ml
c. Decrease of 20 to 30 ml
d. No change

ANS: A
In general, VT reduces between 50 and 70 ml for each 6 in (15 cm) of dead space added by tub-ing in a circuit.