Body-plethysmographic pressure-flow diagrams in chronic obstructive lung disease. II. Functional assessment

One hundred patients with various forms of chronic obstructive lung disease (COLD) were allocated to groups according to their body-plethysmographic pressure-flow diagrams. Group I comprised 30 patients with resistance curves displaying linear relationship between pressure and flow. The second group (n = 30) was formed by patients who had a markedly pronounced hysteresis in the central parts of their resistance curves. Group III consisted of 30 patients who exhibited resistance curves with distended expiratory sections. Group IV's patients (n = 10) had eight-shaped resistance curves. The lung function profiles of these patients were obtained by measuring the parameters of forced expiration and static lung volumes, the diffusion, blood-gas and acid-base parameters. The analysis of the results shows progressive aggravation of airway obstructions from Group I to Groups III and IV the latter two groups having similar lung function characteristics. Another corollary is that the resistance curve configuration reflects to a great extent the severity of the lung mechanics disorders, but does not correspond entirely to the clinically established forms of the chronic obstructive lung disease.