Maximum Voluntary Ventilation and Its Relationship With Clinical Outcomes in Subjects With COPD.

BACKGROUND: Previous studies have reported that maximum voluntary ventilation (MVV) may be better associated with commonly used outcomes in COPD than FEV1 and may provide information on respiratory mechanics. In this study, we aimed to investigate the relationship between MVV and clinical outcomes in COPD and to verify whether MVV predicts these outcomes better than FEV1. METHODS: We conducted a cross-sectional study involving individuals with COPD. Lung function was assessed with spirometry; maximum inspiratory and expiratory pressures (PImax and PEmax, respectively) were assessed with manuvacuometry; and functional exercise capacity was assessed with the 6-min-walk test (6MWT). Dyspnea was assessed with the modified Medical Research Council (mMRC) scale; functional status was assessed with the modified Pulmonary Functional Status and Dyspnea Questionnaire (PFSDQ-m); and health status was assessed with the COPD Assessment Test (CAT). Correlations were verified with the Spearman coefficient, and stepwise multiple linear regression models investigated the predictors of clinical outcomes. RESULTS: Our study included 157 subjects: 82 males; median (interquartile range) age 66 (61-73) y; FEV1 46 (33-57) % predicted; 6MWT 86 (76-96) % predicted; PFSDQ-m total score 34 (14-57); and CAT total score 13 (7-19). Moderate correlations were found between MVV and PImax (r = 0.40), 6MWT (r = 0.50), mMRC (r = -0.56), and total scores on the PFSDQ-m (r = -0.40) and the CAT (r = -0.54). In the regression models, MVV was a predictor of almost all clinical outcomes, unlike FEV1. CONCLUSIONS: MVV correlates moderately with clinical outcomes commonly used in the evaluation of individuals with COPD, and MVV is a better predictor of respiratory muscle strength, functional exercise capacity, and patient-reported outcomes than FEV1.

Correlação entre a diferença da capacidade vital lenta e forçada com a atividade física na vida diária em pacientes com Doença Pulmonar Obstrutiva Crônica / Correlación entre la diferencia en la capacidad vital lenta y forzada con la actividad física en la vida diaria de pacientes con Enfermedad Pulmonar Obstructiva Crónica / Relationship between the difference of slow and forced vital capacity and physical activity in daily life in patients with Chronic Obstructive Pulmonary Disease

RESUMO O objetivo do estudo foi correlacionar a diferença entre capacidade vital lenta (CVL) e capacidade vital forçada (CVF) (CVL-CVF) com a atividade física na vida diária (AFVD) em pacientes com doença pulmonar obstrutiva crônica (DPOC); e verificar as diferenças na AFVD entre indivíduos com CVL maior ou menor do que a CVF. Vinte e oito indivíduos com DPOC (18 homens; 67±8 anos; VEF1: 40±13% previsto) tiveram a função pulmonar avaliada pela espirometria e foram divididos em dois grupos: CVL>CVF (n=17) e CVL≤CVF (n=11). Ademais, tiveram a AFVD avaliada objetivamente pelo monitor de atividade física DynaPort®, que quantifica na vida diária, dentre outros, o tempo gasto por dia andando, em pé, sentado e deitado. Não foram encontradas correlações significativas entre CVL-CVF e as variáveis da AFVD no grupo geral. No grupo CVL>CVF foi encontrada significância estatística na correlação entre a CVL-CVF e o tempo gasto por dia em pé (r=−0,56) e sentado (r=0,75). Já no grupo CVL≤CVF, houve correlação significativa somente com o tempo gasto por dia em pé (r=0,57) e deitado (r=−0,62). Ao comparar ambos os grupos, não houve diferença estatisticamente significante para nenhuma das variáveis da AFVD (p>0,05 para todas). No grupo com CVL maior que a CVF houve correlação alta com o tempo gasto sentado, mas não com o tempo andando. Portanto, indivíduos com maior obstrução ao fluxo aéreo segundo a diferença CVL-CVF tendem a gastar mais tempo em atividades de menor gasto energético, que não envolvam caminhar.

RESUMEN El presente estudio tuvo el objetivo de correlacionar la diferencia entre la capacidad vital lenta (CVL) y la capacidad vital forzada (CVF) (CVL-CVF) con la actividad física en la vida diaria (AFVD) de pacientes con enfermedad pulmonar obstructiva crónica (EPOC); y verificar las diferencias de la AFVD entre individuos con CVL mayor o menor que la CVF. Se evaluaron la función pulmonar de veintiocho personas con EPOC (18 hombres; 67±8 años; VEF1: 40±13% esperado) mediante espirometría, y los dividieron en dos grupos: CVL>CVF (n=17) y CVL≤CVF (n=11). La AFVD también se evaluó objetivamente por el monitor de actividad física DynaPort®, el cual cuantifica el tiempo que se gasta en la vida diaria caminando, de pie, sentado y acostado. No se encontraron correlaciones significativas entre CVL-CVF y las variables de la AFVD en el grupo general. En el grupo CVL>CVF, se encontró una significación estadística en la correlación entre CVL-CVF y el tiempo que se gasta diariamente en pie (r=−0,56) y sentado (r=0,75). El grupo CVL≤CVF presentó una correlación significativa solo con el tiempo que se gasta diariamente en pie (r=0,57) y acostado (r=−0,62). La comparación entre ambos grupos no resultó en diferencias estadísticamente significativas en ninguna de las variables de AFVD (p>0,05 para todas). En el grupo con CVL mayor que la CVF, hubo una alta correlación con el tiempo que se gasta sentado, pero con el tiempo que se gasta caminando no se encontró este resultado. Se concluye que las personas con una mayor obstrucción del flujo de aire de acuerdo con la diferencia CVL-CVF tienden a gastar más tiempo en actividades con menos gasto de energía, las que no implican caminar.

ABSTRACT The aim of this study was to correlate the difference of vital capacity (VC) and forced vital capacity (FVC) (VC-FVC) with physical activity in daily life (PADL) in patients with chronic obstructive pulmonary disease (COPD); and investigate the differences in PADL in individuals with VC smaller or greater than FVC. Twenty-eight patients with COPD (18 men, 67±8 years; FEV1: 40±13% predicted) had their lung function assessed by spirometry and were divided into two groups: VC>FVC (n=17) and VC≤CVF (n=11). Furthermore, they had their PADL evaluated by a validated activity monitor which measures, among other variables, time spent/day walking, standing, sitting and lying. There were no correlations between VC-FVC and the variables of PADL in the general group. In the group VC>FVC there was statistically significant correlation between VC-FVC and the time spent/day standing (r=−0.56) and sitting (r=0.75). In the group VC≤CVF , VC-FVC was significantly correlated with time spent/day standing (r=0.57) and lying (r=−0.62). When comparing the groups, there was no statistically significant difference for any variable of PADL (p>0.05 for all). In conclusion, in patients with VC greater than FVC there was high correlation with time spent/day sitting, but not with time spent/day walking. Therefore, individuals with greater airflow obstruction according to the VC-FVC difference tend to spend more time in activities of lower energy expenditure, which do not involve walking.

Cluster analysis identifying patients with COPD at high risk of 2-year all-cause mortality.

The objective of the article is to identify clusters of patients with COPD according to factors known to be associated with mortality and to verify whether clusters' assignment is associated with 2-year mortality. Patients ( n = 141) were evaluated by bioelectrical impedance, maximal inspiratory pressure (MIP), one-repetition maximum test of the quadriceps femoris (1RMQF) and BODE index (body mass index; airflow obstruction (spirometry); dyspnea (modified Medical Research Council scale); and exercise capacity (6-minute walk test (6MWT) distance). Vital status was retrospectively checked 2 years after the assessments, and time to death was quantified for those deceased in this period. K-means analysis identified two clusters. Patients in cluster one (CL I, n = 69) presented an impaired clinical status in comparison to cluster two (CL II, n = 72). Receiver operating characteristics curves identified the cutoffs discriminating patients composing CL I: forced expiratory volume in the first second <44%pred; 6MWT <479 m; 1RMQF <19 kg; and maximum inspiratory pressures <73 cmH2O (area under the curve range 0.750-0.857). During the follow-up, 19 (13%) patients deceased, 15 in CL I (22%) and 4 in CL II (0.06%) ( p = 0.005). CL I was associated with a higher risk of 2-year mortality (hazard ratio (95% confidence interval): 4.3 (1.40-12.9), p = 0.01). A cluster of patients with COPD highly associated with 2-year mortality was statistically identified, and cutoffs to identify these subjects were provided.

Difference Between Slow and Forced Vital Capacity and Its Relationship with Dynamic Hyperinflation in Patients with Chronic Obstructive Pulmonary Disease.

The aim of the study was to investigate the relationship between slow and forced vital capacity (SVC-FVC) difference with dynamic lung hyperinflation (DH) during the 6-min walking test (6MWT) in subjects with chronic obstructive pulmonary disease (COPD). Twenty-four subjects with COPD (12 males; 67 ± 6 years; forced expiratory volume in first second [FEV1] 56 ± 18% predicted) performed lung function tests by spirometry and plethysmography. DH was assessed by serial measurements of inspiratory capacity (IC) performed during the 6MWT and defined as ∆IC ≥ 150 mL or 10%. IC decrease significantly during the 6MWT (ΔCI: - 0.48 ± - 0.40 L; P < 0.0001), and 18 individuals (75%) presented DH. There was significant difference when comparing IC measured at rest with the other serial IC measurements (P < 0.0001). Correlation between the SVC-FVC difference and DH during the 6MWT was r = - 0.38; P = 0.06. The SVC-FVC difference presented only weak correlation with the development of DH during the 6MWT in patients with COPD.

Oxygen Desaturation in Daily Life and During a Laboratory-Based Protocol of Activities of Daily Living in COPD: Is There Relationship?

PURPOSE: To analyze the relationship between oxygen desaturation episodes during a laboratory-based ADL protocol and in real-life routine in patients with stable chronic obstructive pulmonary disease (COPD). METHODS: Twenty patients with stable COPD (12 men, 70 ± 7 years, FEV1% 54 ± 15 predicted) with no indication for long-term oxygen therapy (LTOT) were submitted to assessments including ADL performance by the Londrina ADL Protocol (LAP) and level of physical activity in daily life, both while submitted to simultaneous activity and pulse oximeter monitoring. RESULTS: Episodes of desaturation ≥ 4% (ED ≥ 4%) during the LAP were correlated both with ED ≥ 4% in daily life (r = 0.45) and number of episodes of SpO2 under 88% (ED < 88%) in daily life (r = 0.59). ED < 88% during the LAP was also correlated with ED < 88% in daily life (r = 0.51), explaining 43% of its variance. CONCLUSION: In stable patients with COPD and no indication of LTOT, episodes of desaturation during a lab-based ADL protocol are moderately related to episodes of desaturation in daily (real) life, especially those episodes under 88%.

Sedentary Behavior Is an Independent Predictor of Mortality in Subjects With COPD.

BACKGROUND: The terms sedentary behavior and physical inactivity have been confusingly mixed. Although the association between physical inactivity and mortality has been shown previously in subjects with COPD, this association had not yet been investigated with regard to sedentarism. The aim of this work was to investigate the impact of sedentary behavior on mortality of subjects with COPD and to propose a cutoff point of sedentarism with prognostic value. METHODS: In this retrospective cohort study, sedentary behavior was assessed with 2 activity monitors (DynaPort and Sensewear armband) in 101 subjects with COPD from 2006 to 2011. Vital status was then ascertained in 2015. The following 6 variables of sedentary behavior were analyzed: average of metabolic equivalent of task (MET)/d (reflecting intensity); time spent/d lying, sitting, and lying + sitting (reflecting duration of sedentary postures); and time spent/d in activities requiring <1.5 MET and <2 MET (reflecting intensity and duration of sedentary time). Cutoff points for sedentarism and their respective prognostic values were investigated for each variable. RESULTS: Forty-one subjects (41%) died over a median (interquartile range) follow-up period of 62 (43-88) months. After adjusting for potential confounders in the Cox regression model, cutoff points from variables that combine duration of sedentary time and intensity <1.5 MET or <2 MET were associated with the increased risk of mortality. The strongest independent cutoff for predicting mortality was ≥8.5 h/d spent in sedentary activities <1.5 MET (area under the curve 0.76; hazard ratio 4.09, 95% CI 1.90-8.78; P < .001). CONCLUSIONS: Sedentary behavior was an independent predictor of mortality in subjects with COPD, even adjusting for moderate-to-vigorous physical activity and a number of other variables. Mortality was higher in subjects with COPD who spend ≥8.5 h/d in activities requiring <1.5 MET. These findings may open room for future studies aiming at decreasing sedentary time as a promising strategy to reduce mortality risk in subjects with COPD.

Londrina Activities of Daily Living Protocol: Reproducibility, Validity, and Reference Values in Physically Independent Adults Age 50 Years and Older.

BACKGROUND: It is important to assess activities of daily living (ADL) in older adults due to impairment of independence and quality of life. However, there is no objective and standardized protocol available to assess this outcome. Thus, the aim of this study was to verify the reproducibility and validity of a new protocol for ADL assessment applied in physically independent adults age ≥50 y, the Londrina ADL protocol, and to establish an equation to predict reference values of the Londrina ADL protocol. METHODS: Ninety-three physically independent adults age ≥50 y had their performance in ADL evaluated by registering the time spent to conclude the protocol. The protocol was performed twice. The 6-min walk test, which assesses functional exercise capacity, was used as a validation criterion. A multiple linear regression model was applied, including anthropometric and demographic variables that correlated with the protocol, to establish an equation to predict the protocol's reference values. RESULTS: In general, the protocol was reproducible (intraclass correlation coefficient 0.91). The average difference between the first and second protocol was 5.3%. The new protocol was valid to assess ADL performance in the studied subjects, presenting a moderate correlation with the 6-min walk test (r = -0.53). The time spent to perform the protocol correlated significantly with age (r = 0.45) but neither with weight (r = -0.17) nor with height (r = -0.17). A model of stepwise multiple regression including sex and age showed that age was the only determinant factor to the Londrina ADL protocol, explaining 21% (P < .001) of its variability. The derived reference equation was: Londrina ADL protocolpred (s) = 135.618 + (3.102 × age [y]). CONCLUSIONS: The Londrina ADL protocol was reproducible and valid in physically independent adults age ≥50 y. A reference equation for the protocol was established including only age as an independent variable (r2 = 0.21), allowing a better interpretation of the protocol's results in clinical practice.

Development, Validity and Reliability of the Londrina Activities of Daily Living Protocol for Subjects With COPD.

BACKGROUND: To avoid symptoms, patients with COPD may reduce the amount of activities of daily living (ADL). Therefore, the aim of the present study was to develop a standardized protocol to evaluate ADL performance in subjects with COPD (Londrina ADL protocol) and to assess the validity and reliability of the protocol in this population. METHODS: The Londrina ADL protocol was created based on activities included in previous studies aimed at investigating outcomes from ADL. Activities were included in the protocol because they could represent other activities of similar patterns and because they could be actually performed, not simulated. Twenty subjects with COPD (12 men, 70 ± 7 y old, FEV1 = 54 ± 15% predicted) wore 2 motion sensors while performing the protocol 4 times, 2 of them wearing a portable gas analyzer. Subjects were also submitted to assessments of lung function, functional exercise capacity, functional status, impact on health status, and physical activity in daily life. RESULTS: The Londrina ADL protocol comprised of 5 activities representing ADL, involving upper limbs, lower limbs, and trunk movements. Londrina ADL protocol duration presented high values of intraclass correlation coefficient, even using a mask for gas analysis (intraclass correlation coefficient >0.90, P < .001). Intensity of movement during the protocol performance was highly correlated to intensity of movement in daily life (r = 0.71). The protocol duration was correlated with functional status and impact on health status variables from questionnaires (0.36 ≤ r ≤ 0.59). There was also correlation between functional exercise capacity and the protocol duration (r = -0.64). CONCLUSIONS: The Londrina ADL protocol was a valid and reliable protocol to evaluate ADL performance in subjects with COPD. It is a protocol that can be used in clinical practice and in future studies to investigate ADL outcomes, including those studies that require gas analysis and the wearing of a mask.

Analysis of three different equations for predicting quadriceps femoris muscle strength in patients with COPD.

OBJECTIVE: To compare equations for predicting peak quadriceps femoris (QF) muscle force; to determine the agreement among the equations in identifying QF muscle weakness in COPD patients; and to assess the differences in characteristics among the groups of patients classified as having or not having QF muscle weakness by each equation. METHODS: Fifty-six COPD patients underwent assessment of peak QF muscle force by dynamometry (maximal voluntary isometric contraction of knee extension). Predicted values were calculated with three equations: an age-height-weight-gender equation (Eq-AHWG); an age-weight-gender equation (Eq-AWG); and an age-fat-free mass-gender equation (Eq-AFFMG). RESULTS: Comparison of the percentage of predicted values obtained with the three equations showed that the Eq-AHWG gave higher values than did the Eq-AWG and Eq-AFFMG, with no difference between the last two. The Eq-AHWG showed moderate agreement with the Eq-AWG and Eq-AFFMG, whereas the last two also showed moderate, albeit lower, agreement with each other. In the sample as a whole, QF muscle weakness (< 80% of predicted) was identified by the Eq-AHWG, Eq-AWG, and Eq-AFFMG in 59%, 68%, and 70% of the patients, respectively (p > 0.05). Age, fat-free mass, and body mass index are characteristics that differentiate between patients with and without QF muscle weakness. CONCLUSIONS: The three equations were statistically equivalent in classifying COPD patients as having or not having QF muscle weakness. However, the Eq-AHWG gave higher peak force values than did the Eq-AWG and the Eq-AFFMG, as well as showing greater agreement with the other equations.

Analysis of three different equations for predicting quadriceps femoris muscle strength in patients with COPD / Análise de três diferentes fórmulas de predição de força muscular do quadríceps femoral em pacientes com DPOC

AbstractObjective: To compare equations for predicting peak quadriceps femoris (QF) muscle force; to determine the agreement among the equations in identifying QF muscle weakness in COPD patients; and to assess the differences in characteristics among the groups of patients classified as having or not having QF muscle weakness by each equation.Methods: Fifty-six COPD patients underwent assessment of peak QF muscle force by dynamometry (maximal voluntary isometric contraction of knee extension). Predicted values were calculated with three equations: an age-height-weight-gender equation (Eq-AHWG); an age-weight-gender equation (Eq-AWG); and an age-fat-free mass-gender equation (Eq-AFFMG).Results: Comparison of the percentage of predicted values obtained with the three equations showed that the Eq-AHWG gave higher values than did the Eq-AWG and Eq-AFFMG, with no difference between the last two. The Eq-AHWG showed moderate agreement with the Eq-AWG and Eq-AFFMG, whereas the last two also showed moderate, albeit lower, agreement with each other. In the sample as a whole, QF muscle weakness (< 80% of predicted) was identified by the Eq-AHWG, Eq-AWG, and Eq-AFFMG in 59%, 68%, and 70% of the patients, respectively (p > 0.05). Age, fat-free mass, and body mass index are characteristics that differentiate between patients with and without QF muscle weakness.Conclusions: The three equations were statistically equivalent in classifying COPD patients as having or not having QF muscle weakness. However, the Eq-AHWG gave higher peak force values than did the Eq-AWG and the Eq-AFFMG, as well as showing greater agreement with the other equations.

ResumoObjetivo:Comparar diferentes fórmulas de predição do pico de força muscular do quadríceps femoral (QF); investigar a concordância entre elas para identificar fraqueza muscular de QF em pacientes com DPOC; e verificar as diferenças nas características nos grupos de pacientes classificados com presença ou ausência dessa fraqueza de acordo com cada fórmula.Métodos: Cinquenta e seis pacientes com DPOC foram avaliados quanto ao pico de força muscular do QF por dinamometria (contração isométrica voluntária máxima de extensão de joelho). Os valores preditos foram calculados com três fórmulas: uma fórmula composta por idade-altura-peso-gênero (F-IAPG); uma por idade-peso-gênero (F-IPG); e uma por idade-massa magra-gênero (F-IMMG).Resultados: A comparação da porcentagem do predito obtida pelas fórmulas mostrou a F-IAPG com maiores valores do que os valores de F-IPG e F-IMMG, sem diferença entre as duas últimas. A F-IAPG apresentou concordância moderada com F-IPG e F-IMMG, enquanto essas últimas também apresentaram concordância moderada, mas menor, entre si. Do total de pacientes, a fraqueza muscular de QF (< 80% do predito) foi identificada por F-IAPG, F-IPG e F-IMMG em 59%, 68% e 70% dos pacientes, respectivamente (p > 0,05). Idade, massa magra e índice de massa corpórea são características que diferenciam pacientes com e sem fraqueza muscular de QF.Conclusões: As três fórmulas foram estatisticamente equivalentes para classificar pacientes com DPOC como portadores ou não de fraqueza muscular de QF. Entretanto, a F-IAPG apresentou maiores valores de pico de força do que F-IPG e F-IMMG, assim como maior concordância com as outras fórmulas.

GOLD B-C-D groups or GOLD II-III-IV grades: Which one better reflects the functionality of patients with chronic obstructive pulmonary disease?

The aim of this article is to investigate which global initiative for chronic obstructive lung disease (GOLD) classification (B-C-D or II-III-IV) better reflects the functionality of patients with moderate to very severe chronic obstructive pulmonary disease (COPD). Ninety patients with COPD were classified according to the GOLD B-C-D and II-III-IV classifications. Functionality was assessed by different outcomes: 6-min walk test (6MWT), activities of daily living (ADL) (London Chest ADL Scale), and daily life activity/inactivity variables assessed by activity monitoring (SenseWear armband, Pittsburgh, Pennsylvania, USA). The 6MWT was the only outcome significantly associated with both the GOLD classifications. Good functionality as assessed by the 6MWT was observed in 80%, 69%, and 43.5% (GOLD B, C, and D, respectively) and 81%, 59%, and 29% (GOLD II, III, and IV, respectively) of the patients. Association (V Cramer's) and correlation (Spearman) coefficients of 6MWT with GOLD B-C-D and II-III-IV were V = 0.30, r = -0.35, and V = 0.37, r = -0.25, respectively. Neither GOLD classification showed V or r ≥ 0.30 with any other functionality outcome. Both the GOLD B-C-D and II-III-IV classifications do not reflect well COPD patients' functionality. Despite low association and correlation coefficients in general, both GOLD classifications were better associated with functional exercise capacity (6MWT) than with subjectively assessed ADL and objectively assessed outcomes of physical activity/inactivity.

Relationship between sniff nasal inspiratory pressure and BODE index in patients with COPD.

PURPOSE: The aims of this study were to investigate the relationship between sniff nasal inspiratory pressure (SNIP) and severity of chronic obstructive pulmonary disease (COPD) as defined by the BODE index, and to investigate the capacity of different SNIP cutoffs to predict a BODE index score ≥5 (i.e., worse disease severity). METHODS: Thirty-eight subjects with COPD (21 men, 66 ± 8 years, forced expiratory volume in the first second (FEV(1)) 42 ± 16 % predicted) underwent assessments of SNIP, airflow limitation, body mass index (BMI), dyspnea (Medical Research Council scale), and exercise capacity (6-min walking test, 6MWT). The BODE index was calculated, and patients were separated into two groups according to the BODE quartiles (1 and 2, or 3 and 4). RESULTS: Patients from quartiles 3 and 4 presented lower values of SNIP than patients from quartiles 1 and 2 (73 ± 18 vs 56 ± 21 cmH(2)O, respectively; p = 0.01). There was significant and inverse correlation between SNIP and the BODE index (r = -0.62; p<0.001). A logistic regression model revealed that a SNIP value below 63 cmH(2)O presented higher sensitivity and specificity (70 and 67 %, respectively) for predicting a BODE score equivalent to quartiles 3 or 4. CONCLUSION: SNIP is moderately and significantly related to COPD severity as assessed by the BODE index. Moreover, the cutoff point of 63 cmH2O showed the best combination of sensitivity and specificity for predicting worse scores in the BODE index.

Spirometry in healthy subjects: do technical details of the test procedure affect the results?

INTRODUCTION: Spirometry should follow strict quality criteria. The American Thoracic Society (ATS) recommends the use of a noseclip; however there are controversies about its need. ATS also indicates that tests should be done in the sitting position, but there are no recommendations neither about position of the upper limbs and lower limbs nor about who should hold the mouthpiece while performing the maneuvers: evaluated subject or evaluator. OBJECTIVES: To compare noseclip use or not, different upper and lower limbs positions and who holds the mouthpiece, verifying if these technical details affect spirometric results in healthy adults. METHODS: One hundred and three healthy individuals (41 men; age: 47 [33-58] years; normal lung function: FEV1/FVC = 83±5, FEV1 = 94 [88-104]%predicted, FVC = 92 [84-102]%predicted) underwent a protocol consisting of four spirometric comparative analysis in the sitting position: 1) maximum voluntary ventilation (MVV) with vs without noseclip; 2) FVC performed with vs without upper limbs support; 3) FVC performed with lower limbs crossed vs lower limbs in neutral position; 4) FVC, slow vital capacity and MVV comparing the evaluated subject holding the mouthpiece vs evaluator holding it. RESULTS: Different spirometric variables presented statistically significant difference (p<0.05) when analysing the four comparisons; however, none of them showed any variation larger than those considered as acceptable according to the ATS reproducibility criteria. CONCLUSIONS: There was no relevant variation in spirometric results when analyzing technical details such as noseclip use during MVV, upper and lower limb positions and who holds the mouthpiece when performing the tests in healthy adults.

Respiratory muscle strength during and after hospitalization for COPD exacerbation.

BACKGROUND: A more profound investigation of respiratory muscle strength during COPD exacerbation was needed, so we investigated respiratory muscle strength and related factors in patients with COPD during and after hospitalization for COPD exacerbation. METHODS: In 19 subjects hospitalized for COPD exacerbation (12 males, mean age 67 ± 11 y, median percent-of-predicted FEV(1) 26% [IQR 19-32%]) we measured lung function and respiratory and quadriceps muscle strength at admission (day 1), at discharge, and 1 month after discharge. RESULTS: At admission, 68% of the subjects had inspiratory muscle dysfunction (maximum inspiratory pressure < 70% of predicted). Inspiratory muscle strength increased between day 1 (56 cm H(2)O [IQR 45-64 cm H(2)O]) and 1 month after discharge (65 cm H(2)O [IQR 51-74 cm H(2)O], P = .007). Expiratory muscle strength increased between day 1 (99 cm H(2)O [65-117 cm H(2)O]) and discharge (109 cm H(2)O [77-136 cm H(2)O], P = .005), and between day 1 and 1 month after discharge (114 cm H(2)O [90-139 cm H(2)O], P = .001). Inspiratory capacity increased between discharge (1.59 ± 0.44 L) and 1 month after discharge (1.99 ± 0.54 L, P = .02). There was no significant change in other lung function variables or quadriceps strength. At admission the inspiratory muscle dysfunction and reduction in inspiratory capacity (< 80% of predicted) correlated linearly (phi coefficient 0.62, P = .03), whereas the expiratory muscle strength correlated inversely with FEV(1) (Spearman rho -0.61, P = .005) and inspiratory capacity (Spearman rho -0.54, P = .02). CONCLUSIONS: There was a high prevalence of inspiratory muscle dysfunction in patients hospitalized for COPD exacerbation. Inspiratory and expiratory muscle strength increased markedly during and after hospitalization. The degree of air-flow obstruction and hyperinflation were related to inspiratory and expiratory muscle strength.

Maximum voluntary ventilation is more strongly associated with energy expenditure during simple activities of daily living than measures of airflow obstruction or respiratory muscle strength in patients with COPD.

This is a retrospective analysis of data in which we explored the association between energy expenditure (EE) and lung function in patients with chronic obstructive pulmonary disease (COPD). A total of 36 participants (20 males; forced expiratory volume in 1 second (FEV(1)) of 48 ± 15% predicted) underwent measures of indirect calorimetry whilst performing five simple activities of daily living. Maximal voluntary ventilation was the only lung function parameter associated with EE. These data highlight the limited extent to which the FEV(1) is related to the functional performance of patients with COPD.

Energy expenditure during daily activities as measured by two motion sensors in patients with COPD.

BACKGROUND: In patients with chronic obstructive pulmonary disease (COPD), energy expenditure (EE) assessment during the performance of daily activities is not yet studied in depth. The aim of this study was to determine which daily activities are more demanding to patients with COPD and to compare the accuracy of EE estimation given by the pedometer Digiwalker SW701 (DW) and the multisensor SenseWear Armband (SAB). METHODS: Thirty-six patients with COPD (20 men; FEV1 48 ± 15%predicted; BMI 25.7 ± 8 kg/m(2)) were submitted to a modified version of the Glittre ADL-test, which included five activities performed for 1 min each: walking on the level, walking on the level carrying a backpack, walking up/downstairs, rising/sitting in chairs and moving objects in and out of a shelf. During the protocol subjects wore both devices concomitantly, and indirect calorimetry (IC) was simultaneously performed as the criterion method to assess EE. RESULTS: The most demanding daily activity for individuals with COPD was walking up/downstairs (4.9 ± 1.7 kcal versus 3.7 ± 1.4 to 4.2 ± 1.8 kcal for the other tasks; p < 0.05). EE estimation by the SAB did not show difference in comparison to IC for the sum of the five activities (SAB = 22.7 ± 7 kcal versus IC = 21 ± 8 kcal; p > 0.05), although overestimation was found in activities involving walking. DW showed significant EE underestimation in the sum of the activities (9.6 ± 4.3 kcal; p < 0.05 versus IC) and for each activity. CONCLUSION: Walking up/downstairs was the most energy-demanding daily activity for patients with COPD. Furthermore, during daily activities, the multisensor showed adequate overall estimation of energy expenditure, as opposed to the pedometer.