Deadspace, invasive and non-invasive.
D000368:Aged; D001944:Breath Tests; D002245:Carbon Dioxide / Q000032:analysis; D006801:Humans; D008297:Male; D011650:Pulmonary Alveoli / Q000502:physiology; D012121:Respiration, Artificial; D012126:Respiratory Dead Space
D002245:Carbon Dioxide