Evaluation of mechanical ventilatory, cardiocirculatory and metabolic responses in dynamic exercise incremental symptom limited trial - FRIENDS Study

Abstract

Introduction: Among the multimorbities most prevalent in the aging process, chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD) are the two main causes of hospital admissions in Brazil. In addition, the prevalence of COPD in patients with CHF is estimated to be 20-30% in the USA, however, it is not clear yet the coexistence of these diseases in our country, nor even about their impact on exercise capacity in a study of follow-up. The association of COPD with CHF can magnify the symptoms, leading to marked mechanical, ventilatory, cardiocirculatory, autonomic, gas exchange, muscular and cerebral blood flow, as well as endothelial and cerebral function changes, further hampering reduced exercise capacity in comparison with the disease in isolation, however, such findings remain to be investigated.Objectives: To evaluate the cardiorespiratory and metabolic determinants of CHF, COPD and coexistence of these diseases during maximal exercise, as well as their implications for prognostic indexes.Study Design: Cross-sectional, longitudinal and comparative intervention study.Subjects: All patients enrolled in the two outpatient clinics (Pulmonology and Cardiology) at the Sao Carlos medical specialty center or after 3 months of exacerbation of the disease in a hospital environment and in the period of clinical stability, patients with a previous diagnosis and / or presence of signs and symptoms of COPD and / or CHF. Of these, they will be divided into 3 groups (CHF, COPD and COPD + CHF) to contrast cardiorespiratory and exercise capacity changes.Methods: Individuals with COPD, CHF and coexistence of CHF + COPD will be invited to perform limited symptom incremental exercise testing with analysis of ventilatory and metabolic (ergo-spirometry), cardiac output (cardioimpedance) ventilation, peripheral and cerebral (NIRS), lactacemia, glycemia and signs and symptoms.Hypothesis of the study: Patients with coexistence of COPD-CHF are predicted to have greater ventilatory inefficiency compared to the isolated disease. It is further envisaged that such indices may be powerful prognostic markers in this subgroup of patients.