The Compararion Between RV/TLC And IC/TLC In Evaluating Of Lung Hyperinflation In Patients With Chronic Obstructive Pulmonary

Objective:By analyzing the correlation between lung static hyperinflation and BDI score, airway limitation, pulmonary diffusion function or BMI in patients with chronic obstructive pulmonary disease, compared RV/TLC and IC/TLC in assessment of lung hyperinflation.Methods:We chose88patients with stable COPD, who underwent spirometry and lung volumes assessment using the single-breath technique. Then the Baseline Dyspnea Index (BDI) was used to evaluate dyspnea with activities of daily living. The relationships between the results were analyzed and multiple linear regressions were obtained by stepwise methods, using SPSS16.0statistical software.Results:The BDI score significantly correlated with IC/TLC and RV/TLC, while the Pearson correlation coefficients were0.525,-0.449(P<0.0001). RV/TLC, BMI, age, FEV1%pred, DLCO%pred were then offered as predictor variables to the multiple regression analysis, with dependent variable of BDI score, FEV1%pred and RV/TLC significantly accounted for21.9%and6.4%of the variance, respectively. RV/TLC was replaced by IC/TLC to evaluate lung static hyperinflation, the BDI score was more significantly explained by IC/TLC (R2=27.5%), while FEV1%pred just accounted12.4%. The Pearson correlation coefficient for IC/TLC, RV/TLC and FEV1%pred was-0.485,0.204(P<0.05). The BMI was correlated with RV, FRC, IC, and IC/TLC. The Pearson coefficient between BMI and IC/TLC was0.434(P< 0.0001), while there was no significant liner correlation between RV/TLC and BMI.Conclusions:1、The static lung hyperinflation was a significant contributor to clinical dyspnea in patients with COPD, which could be reduced with BMI increasing, and the degree of hyperinflation was significant associated with the degree of airways obstruction (the FEV1%predicted).2、Compared with RV/TLC, IC/TLC could be better in assessing lung static hyperinflation, and a more independent, sensitive, multidimensional predictor for evaluating the severity of disease.