Relation between airways obstruction and CO2 tension in chronic obstructive airways disease.

The relationship between the F.E.V.(1) as an index of airways obstruction and Pco(2) as an index of hypoventilation was investigated in 13 patients with chronic obstructive airways disease. Patients who had a normal Pco(2) despite severe airways obstruction retained relatively normal sensitivity to CO(2) as assessed by their "inspiratory mechanical work rate" response to CO(2). Others showed a raised Pco(2) in the presence of lesser degrees of airways obstruction and had reduced sensitivity to CO(2).