Introduction: To compare acute mechanical and metabolic responses of the diaphragm and rib cage inspiratory muscle during two different types of respiratory loading in patients with COPD. Methods: In 16 patients (age:65±13, 56% male, FEV1:60±6%pred, Pimax:82±5%pred) assessments of respiratory muscle electromyography (EMG), esophageal (Pes) and gastric (Pga) pressures, breathing pattern, and noninvasive assessments of systemic (VO2, cardiac output, oxygen delivery and extraction) and respiratory muscle hemodynamic and oxygenation responses (blood flow index [BFI], oxygen delivery index, deoxyhemoglobin concentration [HHb] and tissues oxygen saturation [StiO2]), were performed under two different conditions of respiratory muscle loading (hyperpnea and loaded breathing).Results: During hyperpnea, breathing frequency, minute ventilation, esophageal and diaphragm pressure-time product (PTP)/min, cardiac output and VO2 were higher than during loaded breathing (P<0.05). Average inspiratory Pes and Pdi per breath scalene (SCA), sternocleidomastoid (SCM), and intercostal muscle activation was higher during loading breathing (P<0.05). Higher Pdi during loaded breathing compared to hyperpnea was due to higher Pes (P<0.05). Diaphragm activation, inspiratory and expiratory Pga and expiratory abdominal muscle activation did not differ between the two conditions (P>0.05). SCA-BFI and oxygen delivery index were lower and SCA-HHb was higher during loaded breathing. Furthermore, SCA and intercostal muscle StiO2 were lower during loaded breathing compared to hyperpnea (P<0.05). Conclusion:Greater inspiratory muscle effort during loaded breathing evoked larger ribcage and neck muscle activation compared to hyperpnea. In addition, lower SCA and intercostal muscles 3 StiO2 during loading breathing than during hyperpnea might indicates a mismatch between inspiratory muscle oxygen delivery and utilization.

Aim To provide a Portuguese version of the Multidimensional Dyspnea Profile (MDP), investigating its validity and reliability in Brazilian patients with COPD. Methods This was a cross-sectional study for translation and linguist validation of the Portuguese MDP version for patients with COPD. The process occurred according to the protocol of Mapi Research Trust, Lyon, France. Three scores of MDP were used for the analysis: the immediate unpleasantness of dyspnea (A1); the “immediate perception domain” (S) (sum of A1 plus the sensory descriptors) and the “emotional response domain” (A2) (sum of the emotional descriptors). The questionnaires COPD assessment Test (CAT), Hospital Anxiety and Depression scale (HADS) and Medical Research Council scale (MRC) were used as anchors to investigate MDP’s validity. Internal consistency was assessed with Cronbach’s alpha. Test–retest reliability was assessed with intraclass correlation coefficient (ICC) and concurrent validity was assessed with Spearman correlation coefficients. Results Thirty patients with moderate-severe COPD were studied for MDP’s validation analysis (43% male, 63±8years, body mass index [BMI] 27±6Kg/m 2 , forced expiratory volume in the first second [FEV 1 ] 48±15%predicted, six-minute walking test [6MWT] 464±84m and 84±16%predicted), whereas 10 patients were excluded from the test-retest reliability analysis due to missing data, resulting in a sample of 20 subjects for this purpose (50% male, 62±8years, BMI 27±6Kg/m 2 , FEV 1 48±15%predicted, 6MWT 452±93m and 82±19%predicted). Both samples were similar regarding general characteristics ( P >0,05 for all variables). MDP presented strong correlations, i.e., ICC intra-rater: A1: 0.77 (0.48–0.90), S: 0.78 (0.52–0.91), and A2: 0.85 (0.66–0.94), with high internal consistency (Cronbach's α 0.86, 0.88 and 0.92 respectively); and ICC inter-rater: A1: 0.74 (0.46–0.89), S: 0.75 (0.48–0.89) and A2: 0.91 (0.78–0.96) with Cronbach's α 0.85, 0.86 and 0.95 respectively. Conclusion The Portuguese version of the MDP is the first valid and reliable instrument to assess dyspnea multidimensionally in Portuguese-speaking patients with COPD.

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