: belonging only to the person or group specified. 1  She has the sole authority to hire new staff members. [=only she can hire new staff members] 2  He has sole jurisdiction of the area.
Dr. Stern responded: Dead space in lung. Dead space is a term used to describe an area of the lung where gas exchange cannot occur - it does not mean dead lung tissue. Everyone has dead space and it is comprised mainly of your airways. It is measured as a percentage. Dead space is affected by many variables including the size of the breath we inhale.
There are two different ways to define dead space-- anatomic and physiologic. Anatomic dead space is the total volume of the conducting airways from the nose or mouth down to the level of the terminal bronchioles, and is about 150 ml on the average in humans. The anatomic dead space fills with inspired air at the end of each inspiration, but this air is exhaled unchanged. Thus, assuming a normal tidal volume of 500 ml, about 30% of this air is wasted in the sense that it does not participate in gas exchange.