Negative effects of chronic kidney failure on lung function and functional capacity.

OBJECTIVE: To evaluate lung function and functional capacity in patients with chronic kidney failure (CKF) undergoing dialysis and in patients after kidney transplant. METHODS: Seventy-two participants were evaluated: 32 patients with CKF on dialysis (DG) for at least six months, ten patients who had kidney transplants (TG) at least six months earlier, and 30 healthy subjects as a control group (CG). All groups were evaluated using spirometry, with maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), and using the six-minute walking test (6MWT). The SPSS 12.0 software was used for statistical analysis, with a minimum significance level of alpha<0.05. RESULTS: There was a decreased lung function in the DG for FVC, FEV1, MVV, VC, MIP and MEP, and decreased FEV1 and MVV in the TG compared to the CG (one-way ANOVA/Fisher's post-hoc; p<0.01). There was also an association (chi-square) between decreased MIP and belonging to the DG (alpha=0.5, p<0.001), between lower performance in the 6MWT for the DG and TG (p<0.01) compared to the CG (one-way ANOVA/Fisher's post-hoc), and between MIP and MEP (Pearson's coefficient; r=0.752; p<0.01). CONCLUSIONS: Patients with CKF undergoing dialysis showed impaired functional capacity and lung function that were not completely reverted in the kidney transplant patients.

Efeitos negativos da insuficiência renal crônica sobre a função pulmonar e a capacidade funcional / Negative effects of chronic kidney failure on lung function and functional capacity

OBJETIVO: Avaliar a função pulmonar e a capacidade funcional em pacientes com insuficiência renal crônica (IRC) em hemodiálise e em pacientes após transplante renal. MÉTODOS: Foram avaliados 72 indivíduos, sendo 32 pacientes com IRC em hemodiálise (GD) há mais de 6 meses, 10 pacientes transplantados renais (GT) há, pelo menos, 6 meses e 30 sujeitos saudáveis para grupo controle (GC). Todos os grupos foram avaliados utilizando espirometria, pressões inspiratória (PImax) e expiratória (PEmax) máximas e teste da caminhada em seis minutos (TC6min). Para análise estatística, foi utilizado o programa SPSS 12.0, com nível mínimo de significância α<0,05. RESULTADOS: Foram encontrados resultados estatisticamente significativos (p<0,01) para: diminuição da função pulmonar no GD para Capacidade vital forçada (CVF), Volume expirado forçado (VEF1), Ventilação voluntária máxima (VVM), Capacidade vital (CV), PImax, PEmax e, para o GT, diminuição do VEF1 e VVM, quando comparados ao GC (ANOVA uma via/post hoc Fischer); associação (qui-quadrado) entre diminuição da PImax e pertencer ao GD (α=0,5, p<0,001); menor desempenho no TC6min no GD e GT (p<0,01) quando comparados ao GC (ANOVA uma via/post hoc Fischer). Encontrou-se correlação significativa (coeficiente de Pearson) entre PImax e PEmax (r=0,752, P<0,01). CONCLUSÕES: Pode-se concluir que existem alterações na capacidade funcional e na função pulmonar do paciente com IRC em hemodiálise, as quais são indicativas de prejuízos funcionais que não se apresentam completamente revertidos no paciente transplantado renal.

OBJECTIVE: To evaluate lung function and functional capacity in patients with chronic kidney failure (CKF) undergoing dialysis and in patients after kidney transplant. METHODS: Seventy-two participants were evaluated: 32 patients with CKF on dialysis (DG) for at least six months, ten patients who had kidney transplants (TG) at least six months earlier, and 30 healthy subjects as a control group (CG). All groups were evaluated using spirometry, with maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), and using the six-minute walking test (6MWT). The SPSS 12.0 software was used for statistical analysis, with a minimum significance level of α<0.05. RESULTS: There was a decreased lung function in the DG for FVC, FEV1, MVV, VC, MIP and MEP, and decreased FEV1 and MVV in the TG compared to the CG (one-way ANOVA/Fisher's post-hoc; p<0.01). There was also an association (chi-square) between decreased MIP and belonging to the DG (α=0.5, p<0.001), between lower performance in the 6MWT for the DG and TG (p<0.01) compared to the CG (one-way ANOVA/Fisher's post-hoc), and between MIP and MEP (Pearson's coefficient; r=0.752; p<0.01). CONCLUSIONS: Patients with CKF undergoing dialysis showed impaired functional capacity and lung function that were not completely reverted in the kidney transplant patients.

Step counting and energy expenditure estimation in patients with chronic obstructive pulmonary disease and healthy elderly: accuracy of 2 motion sensors.

OBJECTIVE: To compare the accuracy of 2 motion sensors (a pedometer and a multisensor) in terms of step counting and estimation of energy expenditure (EE) in patients with chronic obstructive pulmonary disease (COPD) and in healthy elderly. DESIGN: In this descriptive study, all participants wore both motion sensors while performing a treadmill walking protocol at 3 different speeds corresponding to 30%, 60%, and 100% of the average speed achieved during a six-minute walk test. As criterion methods, EE was estimated by indirect calorimetry, and steps were registered by videotape. SETTING: Research laboratory at a university hospital. PARTICIPANTS: Patients with COPD (n=30; 17 men; mean age +/- SD, 67+/-8 y; mean forced expiratory volume in the first second [FEV(1)] predicted +/- SD, 46%+/-17%; mean body mass index [BMI] +/- SD, 24+/-4 kg.m(2)) and matched healthy elderly (n=30; 15 men; mean age +/- SD, 68+/-7 y; mean FEV(1) predicted +/- SD, 104%+/-21%; mean BMI +/- SD, 25+/-3 kg.m(2)). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Step counting and EE estimation during a treadmill walking protocol. RESULTS: The pedometer was accurate for step counting and EE estimation in both patients with COPD and healthy elderly at the higher speed. However, it showed significant underestimation at the 2 slower speeds in both groups. The multisensor did not detect steps accurately at any speed, although it accurately estimated EE at all speeds in healthy elderly and at the intermediate and higher speeds in patients with COPD. CONCLUSIONS: In both patients with COPD and healthy elderly, the multisensor showed better EE estimates during most walking speeds than the pedometer. Conversely, for step counting, accuracy is observed only with the pedometer during the higher walking speed in both groups.

Comparison of daily physical activity between COPD patients from Central Europe and South America.

BACKGROUND: In healthy elderly and adults, lower physical activity level in daily life has been associated with lower socio-economic level and non-Caucasian race. The objective of this study was to determine if this is also applicable in chronic obstructive pulmonary disease (COPD) by comparing physical activity levels in daily life in stable patients from two countries (Austria and Brazil) with different socio-economic and ethnic characteristics. METHODS: Physical activity in daily life was objectively assessed in 40 Austrian and 40 Brazilian COPD patients. Groups were matched for age, gender, body mass index, disease severity, smoking history, presence of concomitant heart disease, lung function, dyspnea and functional exercise capacity. In addition, climatic conditions were similar during the period of data collection in the two groups. RESULTS: In comparison to Brazilian patients, Austrian patients had a significantly lower walking time (p=0.04), higher sitting time (p=0.02) and lower movement intensity (p=0.0001). The proportion of patients who did not reach an average of 30min of walking per day was 48% in the Austrian group and 23% in the Brazilian group. CONCLUSIONS: Austrian patients with COPD showed a significantly lower daily physical activity level in comparison to matched Brazilian patients. Socio-economic and ethnic factors appear to influence stable COPD patients differently than described in previous studies including healthy subjects.

Heart rate variability and disease characteristics in patients with COPD.

Heart rate variability (HRV) is reduced in patients with chronic obstructive pulmonary disease (COPD). However, the relationships among HRV and characteristics of COPD are unknown. The aim of this study was to characterize HRV in patients with COPD and to verify the correlation of HRV measured during rest with disease severity and pulmonary, muscular, and functional impairment. Thirty-one patients with COPD (16 male; 66 +/- 8 years; BMI = 24 +/- 6 kg/m(2); FEV(1) = 46 +/- 16% predicted) without severe cardiac dysfunction were included. HRV assessment was performed by the head-up tilt test (HUTT), and the main variables used for analysis were SDNN index, LF/HF ratio, and R-R intervals. Other tests included spirometry, bioelectrical impedance, cardiopulmonary exercise test, 6-minute walk test, respiratory and peripheral muscle force, health-related quality of life and functional status questionnaires, and objective quantification of physical activity level in daily life with the DynaPort and SenseWear armband activity monitors, besides calculation of the BODE index. There was a statistical difference in all variables of HRV between the HUTT positions (lying and standing). There was no correlation of HRV with BODE index or FEV(1). Out of the BODE index, just the BMI was correlated with SDNN and R-R intervals (r = 0.44; p < 0.05 and r = 0.37; p < 0.05, respectively). There was correlation between HRV reduction and a lower level of physical activity in daily life, besides worse health-related quality of life, functional status, and respiratory and peripheral muscle force. Cardiac autonomic function of patients with COPD is not related to disease severity but mainly to the level of physical activity in daily life.

Relationship between pulmonary function and physical activity in daily life in patients with COPD.

BACKGROUND: It remains unclear how closely the physical inactivity observed in patients with Chronic Obstructive Pulmonary Disease (COPD) relates to the severity of their airflow limitation. Furthermore, it is unknown whether spirometric variables such as maximal voluntary ventilation (MVV) and inspiratory capacity (IC) reflect the level of physical activity in daily life better than the forced expiratory volume in the first second (FEV(1)), the main spirometric variable used to determine the severity of COPD. The objective of the present study was to investigate the relationship between physical activity in daily life and the severity of COPD assessed by different spirometric variables: MVV, IC and FEV(1). METHODS: Forty patients with COPD (21 men; 68+/-7 years; FEV(1) 41+/-14% predicted) were performed spirometry and assessment of the physical activity level in daily life using an accelerometer (SenseWear Armband). RESULTS: MVV was significantly correlated to total energy expenditure per day, energy expenditure per day in activities demanding more than 3 metabolic equivalents (METs), number of steps per day and time spent per day in moderate and vigorous activities (0.42

[Validation of the Portuguese version of the London Chest Activity of Daily Living Scale (LCADL) in chronic obstructive pulmonary disease patients].

INTRODUCTION: While there are several subjective English tools, such as the London Chest Activity of Daily Living scale (LCADL), aimed at assessing dyspnoea during activities of daily living (ADL) in patients with Chronic Obstructive Pulmonary Di- sease (COPD), none of these questionnaires has ever been translated into Portuguese. The aim of this study was to investigate the validity and reproducibility of the LCADL's Portuguese version in patients with COPD. METHODS: 31 patients with COPD (17 male; 69+/-7 years; FEV1 44+/-15 %predicted) completed the Portuguese version of the LCADL twice with a 1-week interval. The traditional Saint George Respiratory Questionnaire (SGRQ), already validated in Portuguese, was used as the criterion method. RESULTS: There were no significant differences between test and retest of the LCADL. Intraclass Correlation Coefficient between test and retest concerning the different scale components was Self-care r=0.96; Domestic r=0.99; Physical r=0.92; Leisure r=0.95; Total Score r=0.98. There were significant correlations of the LCADL Total Score with the SGRQ's different components and total score (0.36

Hydrogen peroxide as a tool for studying oxidative stress in the heart

Hydrogen peroxide (H2O2) was observed to depolarize the frog sartorius muscle and promote rhythmic contraction of frog cardiac ventricular rings or their contracture. This last effect was sodium-dependent. H2O2 perfused or injected into the aorta of the isolated rat heart induces a positive inotropic effect (with cardiac arrhythmias such as extrasystolic potentiations) followed by deoression of contractility or cardiac contractures, according to the dose employed. The last effects is similar to the "stone heart"observed in the reperfusion injury and may be ascribed to lipoperoxidation (LPO) of the membrane lipids, to protein damage, to reduction in the ATP level and/or to cardioactive compounds liberated by LPO. Besides its direct effect on the ATP level, H2O2 would react with iron ions to produce hydroxyl radicals that attack the cellular membranes. Deferoxamine, an iron chelator and scavenger of hydroxyl radicals, reduced the contractures induced by H2O2. Perfusion with H2O2 increased the LPO of cardiac homogenates measured by chemiluminescence, oxygen uptake and malonaldehyde formation. The fall in ATP levels and the LPO would result in calcium overload of the cardiac fibers and contracture ("stone heart"). The 45Ca uptake was increased by incubation of cardiac strips with H2O2. Previous perfusion of the isolated rat heart with nifedipine or indomethacin reduced the H2O2 cardiac contracture. Vitamin A, a quencher of singlet oxygen liberated during LPO, reduces the H2O2 cardiac contractures and also LPO. Gradual physical exercises, besides increasing the oxygen consumption, protected the heart from oxidative stress. The experimental production of hypothyroidism protected the heart against the H2O2 oxidative stress. The hearts of rats submitted to hypertension with high renin levels showed increased LPO, measured by chemiluminescence and oxygen uptake, indicating that this condition may be produced by oxygen species or causes their production. All these findings give support to the idea that the ischemia-reperfusion injury is an active oxygen species associated disorder that induces cardiac stiffness or contractures that would be produced by calcium overload. Thus, H2O2 may be useful for inducing experimental oxidative stress in the heart and for studying its oxidative status in physiological and pathological situations.