Calculate the Alveolar ventillation per minute of a patient with respiratory rate 14/min, tidal vol. 500 ml with a vital capacity 7000 ml, :
A i.e. 4900 mlAlveolar ventilation (rest)4.2L/min.QTotal lung capacity4 - 6 lit.4Respiratory minute volume (rest)6 L/min.QMaximum voluntary ventilation125- 170 1/min.QTimed vital capacity - In 1 sec (FeVi)- In 3 sec83%Q97% QWork of quiet breathing0.5 kg - m/minQMaximum work of breathing1D kg- ml breath Alveolar ventilation = (TV - dead space volume) x RR = (500 -150 ml) x 14= 4900 mlNormally we consider dead space to be 150 ml. But also know that 'Dead space volume of a person is equal to twice his body weight i.e. a person weighing 70 kg has a dead space volume of 140 ml.
4900 ml
2000 ml
7700 ml
7000 ml