Evaluation of respiratory parameters in patients with chronic obstructive lung disease during physical exercises

Abstract

Aim. To study the relationship between the indicators of dynamic capnography and pulse oximetry with the indicators of the 6-minute walk test (6MWT) in patients with chronic obstructive pulmonary disease (COPD). Materials and methods. 67 patients of both sexes were examined: 45 patients with COPD (age 60.0±2.74 years) and 25 patients of the control group (age 47.60±3.46 years). The study of the functional capabilities of the patient's respiratory system was carried out before, during and after the 6MWT on the equipment LifeSense LS1-9R capnograph-pulse oximeter (MedAir AB). Results and discussion. In the comparison group, the parameters of dyspnea at rest were higher than the control group (p<0.05), the spirometry indices were significantly lower (p<0.05). Shortness of breath as a reason for stopping/slowing down the pace during the 6MWT was noted by patients of both groups (p<0.05). When analyzing the PETCO2 trend graphs, periodic breathing (PB) was revealed. In the group of patients with COPD, signs of PB in the analysis of the PETCO2 trend were found in 80.95% (p<0.05). Regression analysis of Cox proportional risks of mortality in patients with COPD revealed the prognostic value of the following parameters of a comprehensive assessment of the patient: body mass index (BMI), BODE index, dyspnea index on the mMRS scale, Borg, forced expiratory volume in 1 second (FEV1), index Tiffno, signs of PB, distance 6MWT, signs of PB and desaturation during 6MWT. At the same time, the total contribution of these indicators to the risk of a lethal event was assessed (p=0.003). Conclusion. When analyzing the correlation dependence, it was revealed that the presence of PB was a prognostically unfavorable sign in patients with COPD. Predictors of an unfavorable course of COPD were BMI (<23.0 kg/m2), BODE index, dyspnea indices on the mMRS, Borg, FEV1 scales, Tiffno's index, signs of PH, distance 6MST, signs of PD and desaturation during 6MST (reliability of the model coefficient p=0.003) in terms of forecast.