Physically active patients with COPD have proportionally more FFM and less FM than inactive patients. More pronounced physical inactivity occurs in obese patients, although body composition does not qualify as an important correlate factor of the level of PADL in patients with COPD.

BackgroundDuring protective mechanical ventilation, electrical impedance tomography (EIT) is used to monitor alveolar recruitment maneuvers as well as the distribution of regional ventilation. This technique can infer atelectasis and lung overdistention during mechanical ventilation in anesthetized patients or in the ICU. Changes in lung tissue stretching are evaluated by monitoring the electrical impedance of lung tissue with each respiratory cycle.ObjectiveThis study aimed to evaluate the distribution of regional ventilation during recruitment maneuvers based on the variables obtained in pulmonary electrical impedance tomography during protective mechanical ventilation, focusing on better lung recruitment associated with less or no overdistention.MethodsProspective clinical study using seven adult client–owned healthy dogs, weighing 25 ± 6 kg, undergoing elective ovariohysterectomy or orchiectomy. The animals were anesthetized and ventilated in volume-controlled mode (7 ml.kg−1) with stepwise PEEP increases from 0 to 20 cmH2O in steps of 5 cmH2O every 5 min and then a stepwise decrease. EIT, respiratory mechanics, oxygenation, and hemodynamic variables were recorded for each PEEP step.ResultsThe results show that the regional compliance of the dependent lung significantly increased in the PEEP 10 cmH2O decrease step when compared with baseline (p < 0.027), and for the nondependent lung, there was a decrease in compliance at PEEP 20 cmH2O (p = 0.039) compared with baseline. A higher level of PEEP was associated with a significant increase in silent space of the nondependent regions from the PEEP 10 cmH2O increase step (p = 0.048) until the PEEP 15 cmH2O (0.019) decrease step with the highest values at PEEP 20 cmH20 (p = 0.016), returning to baseline values thereafter. Silent space of the dependent regions did not show any significant changes. Drive pressure decreased significantly in the PEEP 10 and 5 cmH2O decrease steps (p = 0.032) accompanied by increased respiratory static compliance in the same PEEP step (p = 0.035 and 0.018, respectively).ConclusionsThe regional ventilation distribution assessed by EIT showed that the best PEEP value for recruitment maintenance, capable of decreasing areas of pulmonary atelectasis in dependent regions promoting less overinflation in nondependent areas, was from 10 to 5 cmH2O decreased steps.

Objectives: To study the relationship between the level of physical activity in daily life and disease severity assessed by the BODE index in patients with chronic obstructive pulmonary disease (COPD). Methods: Sixty-seven patients with COPD (36 men) with forced expiratory volume in the first second (FEV 1 ) of 39 (27-47)% predicted and age of 66 (61-72) years old were evaluated by spirometry, dyspnea levels (measured by the Medical Research Council scale, MRC) and by the 6-minute walking test (6MWT). The BODE index was calculated based on the body mass index (weight/height 2 ), FEV 1 , MRC and 6MWT, and then the patients were divided in four quartiles according to their scores (Quartile I: 0 to 2 points, n=15; Quartile II: 3 to 4 points, n=20; Quartile III: 5 to 6 points, n=23; Quartile IV: 7 to 10 points, n=9 Houve correlação modesta entre os escores do índice BODE e o tempo gasto andando/dia, gasto energético total e tempo gasto/ dia em atividades moderadas e vigorosas (-0,32≤ r ≤-0,47; p≤0.01 para todos). Quando comparados os quartis agrupados I+II com III+IV, houve diferença significante entre o tempo gasto andando/dia, gasto energético total e tempo gasto em atividades moderadas (p≤0,05). Conclusão: O nível de AFVD apresenta correlação modesta com a classificação da gravidade da DPOC dada pelo índice BODE, refletindo apenas diferenças entre pacientes com doença leve-moderada e grave-muito grave.Palavras-chave: DPOC; atividades de vida diária; BODE; TC6.

The application of a bronchoconstrictor, usually Methacholine (MCh), in respiratory mechanics studies is usually accompanied by the assessment of respiratory mechanics in a dose–response curve. The MCh used in the dose–response curve can be inhaled (i.h.) and intravenous (i.v.) and there are studies comparing i.v. bolus and i.h. MCh in both mice and rats. However, MCh i.v. can be injected at short time interval (bolus) or in continuous infusion. This comparison is relevant since the way MCh is applied influences the mathematical model. We chose an aging process scenario to compare both protocols. This study aims to compare respiratory mechanics of 3-, 6-, and 10-month SAMR1 mice and how both administration methods (continuous infusion and bolus) impact respiratory mechanics evaluation. Both protocols were capable of assessing the difference among ages and doses in: peak or plateau; and area under the curve analysis. The respiratory mechanics parameters were Rn, G, and H (two-way analysis of variance: groups and doses with a P < 0.05 for all). Also, the infusion protocol presented a higher sensitivity to dose increment. In conclusion, both protocols were able to discriminate intragroup and intergroup differences. In the bolus protocol, the highest value of each curve dose may not correspond to the highest real value, and the loss of this point may be a problematic factor in the sample size. These factors are not present in the infusion protocol. Additionally, at this lineage and age screening, the infusion protocol appeared to be more sensitive to differences among ages when compared to the bolus protocol. Impact statement Respiratory mechanics studies are associated with fundamental research and translational studies; the present work thus investigates this particular matter. Our current research describes differences and similarities between two different ways of administrating a very prevalent bronchoconstrictor (methacholine) in an aging process scenario. The core issue of our work is related with troubles we find with the bolus protocol and the application of the mathematical model used to assess the respiratory mechanics. Our findings reveal the continuous infusion as an alternative to these problems and we hope to provide the proper foundations to a more reliable assessment in the respiratory field.

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Subjects with severe and very severe chronic obstructive pulmonary disease(COPD) present thoracoabdominal asynchrony(TAA) that reduces ventilatory efficiency and exercise capacity. However, no therapeutic intervention has focused on reducing TAA. The purpose of this study was to evaluate the effects of elastic tape(ET) on thoracoabdominal mechanics, dyspnea symptoms, exercise capacity, and physical activity level in non-obese male subjects with severe to very severe COPD. Methods: This crossover, randomized trial included non-obese males with severe to very severe COPD. ET was placed on the chest wall and abdomen to reduce TAA. Subjects were evaluated at 3 hospital visits, each seven days apart. At visit 1, thoracoabdominal kinematic and pulmonary ventilation were evaluated simultaneously by optoelectronic plethysmography and electrical impedance tomography, both at rest and during isoload exercise testing. At visit 2, a cardiopulmonary exercise test(CPET,10W/min) was performed until exhaustion. Between the visits, subjects used physical activity monitor(PAM) for 7 days (at least 5 days of measurement; 10h/day). At visit 3, all the tests were repeated in the opposite order of the previous randomization. Results: During the isoload exercise, subjects with ET presented lower tidal and minute volumes(p=0.01) and reduced TAA(p=0.02) and dyspnea(p=0.04). During the CPET, subjects with ET presented an increase in VO2peak(l/min and ml/kg/min;p=0.01), test duration(p=0.009) and maximal load(p=0.03). Moderate and vigorous physical activity(MVPA), which was assessed by the PAM, was also increased in subjects with ET(p=0.01). ET reduced TAA and dyspnea and increased exercise capacity and the duration of MVPA in non-obese male subjects with severe to very severe COPD.

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Mechanical evaluation of tracheal grafts is of great relevance for transplant research.Although there are some publications demonstrating different techniques of tracheal mechanical evaluation, there is still no definitive or preferred protocol available. Here, we present a simple image processing acquisition system that can be used for in vivo experiments. Six male Wistar rats were submitted to orotracheal intubation and a longitudinal incision was made to expose the trachea. Images of tracheae were acquired from a video camera in different scenarios of bronchoconstriction using methacholine (MCh) (Basal, PBS, MCh 30 μg/kg, MCh 300 μg/kg, and postmetabolized) during imposed-inspiration and imposed-expiration. The area variation ratio (the ratio between areas during expiration vs. inspiration) was 1.1× for the Basal group, while the ratio for MCh 300 µg/kg was 6.5×. The area variation of imaged tracheae was statistically significant at the dose of MCh 300 µg/kg for imposed-inspiration versus imposed-expiration (P = .002). Likewise, elastance data of respiratory mechanics indicated a statistically significant difference at the dose of MCh 300 µg/kg for imposed-inspiration versus imposed-expiration (P = .026). Our image processing analysis protocol presented corresponding behavior when compared to mechanical parameters of the respiratory system. In addition, our image acquisition system was able to highlight the differences between imposed-inspiration and imposed-expiration. Image analysis of the tracheal area variation seems to be in agreement with the elastance of the respiratory system. Taken together, these observations may help future studies of tracheal transplantation for in situ assessment of graft patency.