RESUMO
Objective To observe the characteristics of respiratory airflow in healthy adults and stable chronic obstructive pulmonary disease (COPD) patients by analysis of analyzing tidal breathing flow-volume curves (TBFV). Methods Fifteen stable moderate COPD patients (COPD group) and 15 healthy cases without smoking(healthy control group)were enrolled into the study. No bronchodilators were used in patients of COPD group 8 h before test. Pulmonary function test and TBFV in seated position were measured, and the pressure of oral cavity was monitored concomitantly. Results The levels of percentage of vital capacity (VC%), percentage of forced expiratory volume in the first second (FEV 1)/forced vital capacity (FVC) and percentage of maximum mid-expiratory flow (MMEF%) in COPD group were significantly lower than those in healthy control group (P0.05). The levels of tidal expiratory flow at 50%of the remaining tidal volume/PTEF (TEF50/PTEF) and tidal expiratory flow at 25%of the remaining tidal volume/PTEF (TEF25/PTEF) in healthy control group were significantly higher than those in COPD group:0.54 ± 0.13 vs. 0.40 ± 0.12, 0.28 ± 0.13 vs. 0.20 ± 0.06, P<0.01 or<0.05. No differences were found in peak inspiratory pressure (PI max) and peak expiratory pressure (PE max) between two groups. Conclusions The degree of airflow limitation and the effect of bronchodilator in critical patients could be evaluated by analysis of TBFV parameters. The measurement of TBFV is simple and don′t need special technique. It is worth of promoting.