Precipitous fall of the forced expiratory volume.

Patients attending hospital on account of chronic airways obstruction usually present with breathlessness. Most, at this stage, are found to have a severe reduction of the forced expiratory volume (F.E.V.), but little is known about the nature of the deterioration in ventilatory function in earlier phases of the illness. Two patients are described to show how precipitous this deterioration may be. The observations illustrate that the step-wise drop in function reported in some patients (Howard, 1967) may be sufficiently large to plunge a few individuals from normal levels of ventilatory capacity into severe disability within a few years.