Breathing pattern in chronic obstructive lung diseases and interstitial lung fibrosis

ABSTRACT

The pattern of breathing was studied in 27 patients with chronic obstructive lung diseases [COLD], 17 non-hypercapnic and 10 hypercapnic and 10 patients with diffuse interstitial lung fibrosis [DLF] using mouth piece, nose clip, respirometer. In COLD, the results showed similar pattern in non and hypercapnic patients with exaggeration in the absolute values in later group. They showed high respiratory frequency [f], normal tidal volume [VT] high minute ventilation [MV], short inspiratory time [Ti], very small Ti/T tot [T tot total inspiratory cycle time], high VT/Ti. This indicated that it is contrary to current theory, there is an increase in respiratory center drive in all patients with COLD with or without hypercapnia. So, stimulants to respiratory center are not indicated and may have hazardous effects. In DLF patients, [f] was higher than COLD groups, VT was low than normal. Ti and TE [expiratory time] were low. So, Ti/T tot was within normal in contrast to COLD, Vt/Ti is high. The abnormal breathing pattern in DLF attributed by physico-pathological mechanisms triggered by interstitial lung fibrosis. This work illustrated that pattern of breathing and its components can be studied as a routine test by simple noninvasive method using respirometer to assess respiratory center drive and respiratory timing in health and diseases