Ventilation Response During Physical Testing in Patients with Chronic Heart Failure and Chronic Obstructive Pulmonary Disease

Abstract

Background: The determination of the exercise tolerance of patients with CHF and COPD is of great diagnostic and prognostic significance. For an objective assessment of the level of physical performance, it is recommended to use the test with a 6-minute walk test (6MWT). The use of devices that allow monitoring the indicators ETCO2 and Sp2 during the whole study with the function of memory of results significantly increases the diagnostic value of the test. Purpose: to determine the diagnostic possibilities of applying dynamic monitoring of CO2 and Sp2 indicators during 6MWT. Methods: We studied 160 patients of both sexes. Patients with COPD II-IV, stable course (n = 68, age 64.9 ± 4.82 years), patients with CHF II-IV in New York Heart Association (NYHA) (n = 52, age 58.4 ± 3.24 years). The control group consisted of patients without COPD and CHF (n = 40, age 55.35 ± 6.51 years). Conducted 6MWD in accordance with the recommendations of the European Society of Cardiology and the American Thoracic Society. The patient was instructed that his task was to walk as fast as possible for 6 minutes, while he himself determined the intensity of his load. Shortness of breath was assessed on the Borg scale, VAS, the dynamics of the patient's complaints, objective data (BP, pulse, NPV), a dynamic capnogram was recorded using a LifeSense LS1-9R (MedAir AB), a dynamic Sp2 was recorded using a Spiropalm 6MWT (Cosmed). Results: The study found that the reaction of respiration and gas exchange at rest and during 6MWT in patients with COPD and CHF is different. PETCO2 alone patients with CHF in NYHA class II was 38.2 ± 2.13 mm Hg, in NYHA class III the PETCO2 was 34.4 ± 2.22 mm Hg., in NYHA class IV-32.4 ± 1.14 mm Hg. The value of PETCO2 in patients with COPD II was 36.2 ± 2.43 mm Hg, in patients with COPD III-34.1 ± 1.22 mm Hg., in patients with COPD IV was 32.2 ± 1.13 mm Hg. All patients completed 6MWT. The 6MWT distance in patients with CH in NYHA class II was 384.9 ± 10.56 m, in NYHA class III-298.4 ± 10.24 m, in NYHA class IV-162 ± 6.51 m. The 6MWT distance in patients with COPD II was 432.4 ± 8.9 m, with COPD III-354.7 ± 9.9 m, and with COPD IV-262 ± 9.5 m. 69.2% of patients reported shortness of breath as the main reason for stopping during 6MWD, and significantly more often in the group of patients with COPD (p< 0.05). A significant decrease inthe rate of PETCO2 was observedin all patients with CHF during 6MWD. In the group of patients with COPD, a relative increase in the rate of PETCO2 was observed during the execution of 6MWD. When analyzing the trend of PETCO2, these patients showed signs of periodic respiration, in contrast to the control group. When analyzing the SpO2 index during 6MWD, a decrease in this indicator was found in both groups. Conclusion: the dynamic monitoring of PETCO2 and SpO2 significantly expand the diagnostic value of the standard 6MWD.