Ventilatory efficiency and exercise capacity during exercise in patients with idiopathic pulmonary fibrosis / 中华全科医师杂志

ABSTRACT

Objective To explore the characteristics of ventilatory efficiency and exercise capacity during cardiopulmonary exercise testing in patients with idiopathic pulmonary fibrosis (IPF).Methods Pulmonary function test,arterial blood gas analysis and cardiopulmonary exercise testing were performed in 28 IPF patients (IPF group) from April 2012 to April 2013 and 28 healthy volunteers (control group).And the relevant parameters were measured and compared.Results No significant differences existed in age [(57.8 ±9.8) vs.(59.2 ±5.5) years],gender or body mass index (BMI) [(23.8 ±2.7) vs.(25.0 ± 2.8) kg/m2,P ＞ 0.05].The paramneters of pulmonary function test,such as forced vital capacity ％ predicted (74.8 ± 14.6 vs.101.8 ± 10.8),forced expiratory volume in 1 second ％ predicted (73.8 ± 14.6 vs.97.0 ± 10.1),maximum voluntary ventilation ％ predicted (77.5 ± 14.9 vs.95.4 ±24.5),total lung capacity ％ predicted (75.6 ± 12.4 vs.99.8 ± 5.4),residual volume ％ predicted (80.7 ± 15.4 vs.95.8 ± 11.3),diffusing capacity of lung for carbon monoxide ％ predicted (66.2 ± 13.7 vs.103.2 ± 17.3) in the IPF group,were significantly lower than those of the control group (P ＜ 0.01).The parameters of arterial blood gas analysis,such as PaO2 [(72.7 ± 7.3) vs.(92.6 ± 3.8) mmHg] and SaO2 (94.3 ± 2.1 vs.98.3 ± 0.7),were lower than those of the control group (P ＜ 0.01).Thus P(A-a) O2 in the IPF group was higher than that in the control group (33.3 ± 5.7 vs.17.8 ± 1.9,P ＜0.01).These results strongly suggested that IPF group had restrictive ventilatory dysfunction and impaired gas exchange.The IPF patients had higher VE/VCO2-slope (37.4 ± 5.3 vs.25.7 ± 2.5,P ＜ 0.01) and lowest VE/VCO2 (39.2 ±6.7 vs.30.6 ± 2.7,P ＜ 0.01) than the controls; VE/VCO2 and VD/VT during every period were significantly higher in the IPF group than those in the control group (P ＜ 0.01) ; during peak exercise,peakLoad％pred (70.4 ±±29.9 vs.104.8 ±29.7,P ＜0.01) and peakVO2％pred (68.7 ±29.8 vs.98.7 ±36.4,P =0.001) were significantly lower in the IPF group than those in the control group.In the IPF group,VE/VCO2@AT,VE/VCO2-slope and lowest VE/VCO2 had a negative correlation with DLCO％pred (r=-0.589,P ＜0.01; r=-0.481,P＜0.05; r=-0.527,P＜0.05).In the IPF group,VE/VCO2@AT,VE/VCO2-slope and lowest VE/VCO2 had a negative correlation with peakVO2％ pred (r =-0.548,P ＜ 0.05 ; r =-0.539,P ＜ 0.05 ; r =-0.564,P ＜ 0.05).So the exercise tolerance and ventilation efficiency of the IPF group decreased significantly.Conclusion Cardiopulmonary exercise testing reveals that the ventilation efficiency of IPF patients decreases significantly so as to seriously affect their exercise tolerance