Diferença mínima clinicamente significativa para o teste de endurance em cicloergômetro com suporte ventilatório não invasivo na DPOC: um modelo de previsão

Abstract

Chronic obstructive pulmonary disease (COPD) is characterized by the early onset of dyspnea, which is an important limiting factor of physical activities. Physical rehabilitation using non-invasive ventilation (NIV) is indicated in a portion of this population. The objective of this research was to study a prediction model for the minimum clinically important difference (MCID) to the endurance test (Tlim, maximum exercise tolerance time) on a cycle ergometer with NIV in COPD, and as a secondary objective to study clinical-physiological and of imaging, seeking to predict the outcome for MCID at exercise with NIV (33% increase in Tlim), in a single-blind, randomized crossover clinical trial. The NIV modality of two pressure levels was used, with increments based on symptoms of respiratory discomfort. Thirty patients participated in the study, who underwent baseline pulmonary function assessment, including electromyography (EMG) during the inspiratory capacity (IC) maneuver, incremental cardiopulmonary exercise test (CPET), inspiratory muscle strength (PImax) before and after CPET (%variation) and constant load tests (CBT) with SHAM intervention and randomized NIV. After the tests, the individuals were divided into two groups, according to the level of response: responder (R, n=15) and non-responder (NR, n=15). No clinical or imaging differences were observed between the two groups. Baseline lung function and incremental CPET were similar between the two groups (p>0.050). However, significant differences were observed in the analysis of the %variation of MIP (p<0.010) and in the intensity of the sternocleidomastoid muscle electrical potential during the IC maneuver, at rest (p<0.010). In the multivariate logistic regression analysis, it was possible to create a predictive model with these two variables, which showed a sensitivity of 80% and specificity of 87% to predict the RMCS outcome, associated with NIV in patients with COPD.

Keywords: COPD, Exercise, Noninvasive ventilation.