Joan is breathing 14 times per minute with a tidal volume of

Joan is breathing 14 times per minute, with a tidal volume of 520 mL and a dead space of 152 mL. Lester is breathing 15 times per minute, with a tidal volume of 400 mL and a dead space of 175 ml. Which patient has better alveolar ventilation? Show equations

Solution

Answer: Joan has a better alveolar ventilation

Formula for alveolar ventilation:

Alveolar ventilation = (tidal volume-dead space)Xrespiratory rate

First convert the tidal volume (TV) and dead space(DS) to Litres (that would be 0.520 (TV) and 0.152 for Joan and ).4 and 0.175 for Lester)

if you put the values according above formula,

for Joan, alveolar ventilation = (0.52-0.152)X 14 = 5.152 L/minute

for Lester, alveolar ventilation= (0.4-0.175)X15 =3.375 L/minute