Tuberc Respir Dis.  1990 Mar;37(1):59-65. 10.4046/trd.1990.37.1.59.

A Physiologic Study in Interstitial Lung Disease by Exercise Testing

• KMID: 2528512
• DOI: http://doi.org/10.4046/trd.1990.37.1.59

Abstract

An incremental exercise test was performed in 18 patients with interstitial lung disease Using bicycle ergometer to evaluate the exercise capacity, the pattern of ventilation, and gas exchangé The maximum oxygen uptake (max V0₂ ) was 1.02 ± 0.34 L/ min (46.4 ± 12.9% of predicted value). Anaerobic threshold was determined in 4 among 18 patients, and the oxygen uptake at the determined anaerobic threshold was 0.87 L/ rnin (39.8% of predicted max V0₂ ). The characteristic breathing pattern with exercise was high frequency ventilation, which was more than 50 frequencies/min. with the respect of contribution in the increase of rninute ventilation, the fractional increase of breathing frequency was significantly higher than that of tidal volume (p<0.01). The breathing reserve de. creased to 9.7± l 1.6% , but the heart rate reserve was preserved as 15.3 ± 6.9%. The maximum oxygen pulse was 7.31 ± 2.08 L/ min/beat (59.1± 15.3% of predicted value). The Pa0₂ was 71.1± 11.4 rnmHg at resting and it was significantly decreased to 54.6± l 1.9 mmHg (p<0.01) at maximal exercise and the range of decrease in Pa0₂ was 15.9 ±10.1 mrnHg. The correlation coefficients were investigated between the resting pulmonary function pararneters and the exercise testing pararneters. There were significant correlations between FVC and max V0₂ (r=0.5776, n=18), and between resting Pa0₂ and max V0₂ (r=0.6983, n=15/ p<0.01). It can be concluded that the exercise test might be a valuable tool for determining the degree of physiologic impairment in interstitial lung disease, and the parameters of lung function at resting state may not reflect the exercise capacity which is closely related to the severity of exertional dyspnea.