COMPREHENSIVE EVALUATION OF PARAMETERS OF RESPIRATORY SYSTEM IN 6-MINUTE WALK TEST IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

Aim. To study the relationship of clinical scaling, dynamic capnography, spirometry and pulse oximetry with 6-minute walk test parameters in patients with COPD. Materials and Methods. 121 Patients of both genders were examined: the comparison group consisted of 96 patients with COPD, the control group – 25 practically healthy volunteers. The studied group included patients with I-IV degree COPD: 73 men, 23 women (average age 62.85±8.5 years). The control group was represented by 25 practically healthy volunteers: 9 men, 16 women (average age 47.60±3.46 years). Patients underwent a comprehensive determination of the parameters of the respiratory system: clinical scaling before and after 6MWT, instrumental methods including spirometry, capnography and pulse oximetry before, during and after 6MWT. When analyzing the parameters of dyspnea on the VAS, Borg, mMRS scales at rest, it was found that all parameters were higher in the group of patients with COPD (p <0.05). Spirometry parameters in the comparison group were significantly lower than in the control group (p <0.05). Analysis of the ETCO2 trend at rest revealed a decrease in this parameter with an increase in the severity of COPD (p <0.05). The resting saturation rate in the COPD group was significantly lower than in the control group and amounted to 94.14±2.89, here, with increasing severity of the disease, SpO2 level decreased (p=0.0054). The 6MWT distance in patients varied in a wide range: from 100.75 m to 648.25 m and averaged Me 432.05 [Q 398.25; Q; 483.50]. It should be noted that in the group of «desaturators» the 6MWT distance was significantly shorter than in the group of «non-desaturators». All patients of the COPD group according to the response to the load in 6MWT were divided into two large groups: «desaturators» and «non-desaturators». In the COPD group, normocapnic type of ventilation was observed in the group of «non-desaturators», the ETCO2 trend level was 38.23±2.95 mm Hg, and in the group of «desaturators» the hypercapnic type of ventilation was detected and the ETCO2 trend level was 45.67±2.38 mmHg (p˂0.05). In the compared groups, statistically significant differences were found according to the results of the scales for assessing dyspnea mMRC (p=0.0089) and fatigue (p=0.0018) in the 6MWT, as well as in the level of CO2 (p=0.00081) and SpO2 (p=0.0095) during exercise. In the group of patients with COPD, signs of PB tendency of ETCO2 occurred reliably more often (in 70.83%) than in the control group (Table 3, p˂0.05). Moreover, in the group of «non-desaturators» signs of PB were more common (p=0.014) than in the group of «desaturators» (p=0.046). Conclusions. A comprehensive assessment of the parameters of the respiratory system, including dynamic capnography, pulse oximetry and spirometry, can be recommended as a comprehensive assessment of the parameters of the respiratory system in patients with II-IV degree COPD in order to determine tolerance to exercise, as well as the effectiveness of the therapy.