Assessment of gas compression and lung volume during air stacking maneuver.

PURPOSE: We reasoned that the application of positive pressure through air stacking (AS) technique could cause gas compression and the absolute lung volumes could be estimated. The aim of this study was to estimate the amount of gas compression (ΔV comp) during AS in healthy subjects positioned at 45° trunk inclination and verify if the simultaneous measurements of chest wall volume changes (ΔV CW), by optoelectronic plethysmography, and changes in lung volume (ΔV ao), by pneumotachograph, combined with pressure variation at the airways opening (ΔP ao) during AS are able to provide reliable data on absolute lung volumes. METHODS: Twenty healthy subjects (mean age 23.5 ± 3.8 years) were studied during a protocol that included slow vital capacity and AS maneuvers. V comp was calculated by subtracting ΔV ao and ΔV CW occurring during AS and total lung capacity (TLC) was estimated by applying Boyle-Mariote's law using V comp and ΔP ao. RESULTS: During AS, 0.140 ± 0.050 L of gas was compressed with an average ΔP ao of 21.78 ± 6.18 cmH2O. No significant differences between the estimated TLC (-0.03 ± 3.0% difference, p = 0.6020), estimated FRC (-2.0 ± 12.4% difference, p = 0.5172), measured IC (1.2 ± 11.2% difference, p = 0.7627) and predicted values were found. CONCLUSION: During AS, a significant gas compression occurs and absolute lung volumes can be estimated by simultaneous measurements of ΔV CW, ΔV ao and ΔP ao.

Potential effect of 6 versus 12-weeks of physical training on cardiac autonomic function and exercise capacity in chronic obstructive pulmonary disease.

BACKGROUND: Exercise is an important part of chronic obstructive pulmonary disease (COPD) treatment. However, it is not know about the minimum effective time of physical training that could beneficially modify the cardiac autonomic modulation (CAM) and exercise capacity in these patients. AIM: To contrast the potential effects of a physical training program (PTP), for 6 versus 12 weeks, on CAM by linear and nonlinear heart rate variability (HRV) indices and exercise capacity in COPD patients. DESIGN: Prospective randomized controlled trial. SETTING: Outpatient pulmonary rehabilitation. POPULATION: Twenty moderate-to-severe COPD patients were randomly assigned to either a training group (N.=10) or a control group (N.=10). METHODS: HRV at rest and during submaximal test was determined by linear (rMSSD and SDNN) and non-linear indices (SD1, SD2 and sample entropy [SE]). In addition, key responses were obtained during cardiopulmonary exercise testing (CPET), the walking distance (WD) during the six minute walking test and submaximal constant speed testing (CST). PTP consisted of 30 minutes of aerobic exercise training on a treadmill, 3 times per week at 70% of CPET peak speed rate. Patients were evaluated on baseline, 6 and 12 weeks. RESULTS: Significant improvements in HRV indices, WD, as well as, other physiological responses were observed after 6 weeks of the PTP and maintained until 12 weeks (P<0.05). However, after 12 weeks, the SD1 index demonstrated an additional improvement compared with 6 weeks (P<0.05). Peak oxygen uptake and dioxide carbon production improved only after 12 weeks (P<0.05). Interestingly, the 6th week-baseline delta (6th week-baseline) of WD, SDNN and SE were significantly higher than 12th week-6th week delta (P<0.05). CONCLUSION: These results indicate that beneficial changes on cardiac autonomic modulation in conjunction with improvement in submaximal functional capacity occur in the first 6 weeks of PTP in moderate to severe COPD. CLINICAL REHABILITATION IMPACT: Short-term rehabilitation (6 weeks) is an effective sufficient time to beneficially modify important outcomes as cardiac modulation and exercise capacity in COPD patients.

Assessment of the acute effects of different PEP levels on respiratory pattern and operational volumes in patients with Parkinson's disease.

The aim of the study was to determine the acute effects of positive expiratory pressure (PEP) on breathing pattern, operational volumes and shortening velocity of respiratory muscles on patients with Parkinson's disease. It was evaluated 15 patients and healthy controls, by optoelectronic plethysmography, using PEP in three different levels (10, 15 and 20cmH2O). Breathing pattern changed in both groups. Parkinson group increased tidal volume in all PEP levels (p<0.001), but with lower values compared to control. End-inspiratory chest wall volume increased in the Parkinson group at all PEP levels (p<0.001), end-expiratory chest wall volume show a slightly increase when we compared QB to all PEP levels in Parkinson's. There was an intergroup difference in the index of shortening velocity of abdominal, diaphragm and inspiratory muscles of the rib cage at all PEP levels (p<0.01). We conclude that Parkinson's disease promotes important alterations in different breathing pattern components and PEP has significant effects on these alterations.

Respiratory muscle strength and quality of life in myotonic dystrophy patients.

INTRODUCTION: Studies on quality of life in myotonic dystrophy (MD) are scarce and the relationship between respiratory muscle strength and health-related quality of life (HRQoL) has yet to be determined. The present study aims to investigate respiratory muscle strength and HRQoL and their relationship in MD patients. METHODS: Twenty-three patients (13 men, aged 40 ± 16 years) with MD were evaluated for pulmonary function, maximal inspiratory and expiratory pressure (MIP and MEP, respectively), sniff nasal inspiratory pressure (SNIP) and HRQoL using the Short Form (SF-36) quality of life questionnaire. RESULTS: Respiratory muscle strength values were 71 ± 20 cmH2O (64 % predicted), 76 ± 32 cmH2O (70 % predicted), and 79 ± 28 cmH2O (80 % predicted) for MEP, MIP, and SNIP respectively. Significant differences were found in the SF-36 domains of physical functioning 58.7 ± 31.4 vs. 84.5 ± 23 (p < 0.01, 95 % CI = 1.6-39.9) and physical problems 43.4 ± 35.2 vs. 81.2 ± 34 (p < 0.001, 95 % CI = 19.4-6.1) when compared with the reference values. According to single linear regression analysis, MIP explains 29 % of the variance in physical functioning, 18 % of physical problems and 20 % of vitality. CONCLUSIONS: Individuals with MD have reduced expiratory muscle strength. HRQoL may be more impaired in some physical domains, which might be influenced by variations in inspiratory muscle strength.

Avaliação clínica da capacidade do exercício em pacientes com doença pulmonar obstrutiva crônica: [revisão] / Clinical assessment of exercise capacity in patients with chronic obstructive pulmonary disease: [review]

CONTEXTUALIZAÇÃO: A doença pulmonar obstrutiva crônica (DPOC) se caracteriza por ser uma afecção multissistêmica que leva a uma diminuição na tolerância ao exercício do paciente pneumopata. Atualmente, a Fisioterapia Respiratória dispõe de uma grande variedade de testes validados que tem como característica a sua simplicidade, praticidade e baixo custo. OBJETIVO: Descrever os testes de campo mais utilizados em pacientes com DPOC para avaliar a capacidade de exercício e a atividade física, assim como alguns testes que potencialmente poderiam ser adotados na avaliação clínica destes pacientes. CONCLUSÕES: Para poder justificar a qualidade do trabalho do profissional de Fisioterapia Respiratória, deve-se incorporar os testes utilizados e validados internacionalmente. Além disso, é importante escolher o teste mais adequado para medir a capacidade do exercício e, sobretudo, realizar um seguimento cuidadoso da evolução do paciente.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized as a multisystemic disease that reduces patient's tolerance to exercise. Nowadays, a great variety of validated tests are available for use in Respiratory Physical Therapy that are simple, practical and inexpensive. OBJECTIVE: To describe the tests most used in patients with COPD to evaluate their exercise capacity and physical activity, along with some tests that potentially could be adopted for clinical evaluations in such patients. CONCLUSIONS: To be able to justify the professional quality of the respiratory physical therapists' work, tests that have been used and validated internationally must be incorporated. Moreover, it is important to choose the most appropriate tests for measuring exercise capacity and, above all, to perform a careful follow-up of the patient.

[The relationship between lung function and health-related quality of life in patients with generalized myasthenia gravis]. / Relación entre función pulmonar y calidad de vida relacionada con la salud en la miastenia gravis generalizada.

OBJECTIVE: To study lung function abnormalities and health-related quality of life (HRQL) in a group of patients diagnosed with generalized myasthenia gravis, and to analyze the relationship between these 2 sets of variables. PATIENTS AND METHODS: In a prospective study of 20 patients diagnosed with generalized myasthenia gravis, the following parameters were measured: spirometry, static lung volumes, breathing pattern, maximal respiratory pressures, and maximum voluntary ventilation. HRQL was assessed using the 36-item short form general health questionnaire (SF-36). RESULTS: The mean (SD) age of the patients was 64 (11) years. Patients were classified into 2 groups depending on whether they had IIa (12 patients) or IIb (8 patients) type disease. A small decrease in total lung capacity (86%) and slight reductions in maximal inspiratory pressure (88%) and maximum voluntary ventilation (63% in group IIb) were observed. The HRQL domains most affected were those related to physical activity and self-perceived health status in all groups, although women were more affected. The scores relating to vitality and physical activity were found to be significantly associated with forced vital capacity and lung volumes. Tidal volume was associated with maximal inspiratory and expiratory pressures, inspiratory capacity, and maximum voluntary ventilation. The respiratory rate to tidal volume ratio was inversely associated with the first three of these variables. CONCLUSIONS: A very slight restrictive pattern and a reduction in inspiratory muscle strength were observed. The HRQL domains most affected were those related to physical activity and the patients' self-perceived health status. The weakness of the respiratory muscles contributes to the abnormalities observed in lung function and to the deterioration of health-related quality of life.

Relación entre función pulmonar y calidad de vida relacionada con la salud en la miastenia gravis generalizada / The relationship between lung function and health-related quality of life in patients with generalized myasthenia gravis

Objetivo: Estudiar las alteraciones de la función pulmonar y de la calidad de vida relacionada con la salud (CVRS), así como las relaciones entre ambas áreas, en un grupo de pacientes diagnosticados de miastenia gravis generalizada. Pacientes y métodos: Se ha realizado un estudio prospectivo en 20 pacientes diagnosticados de miastenia gravis generalizada. Se evaluaron la espirometría, los volúmenes pulmonares estáticos, el patrón respiratorio, las presiones respiratorias máximas y la ventilación voluntaria máxima. La CVRS se valoró con el cuestionario general de salud SF-36. Resultados: La edad media (± desviación estándar) de los pacientes fue de 64 ± 11 años. Se clasificaron en IIa (12 pacientes) y IIb (8 pacientes). Se observaron una leve disminución de la capacidad pulmonar total (86%) y una ligera reducción de la presión inspiratoria máxima (88%) y de la ventilación voluntaria máxima (un 63% en el grupo IIb). Los dominios más afectados de la CVRS fueron los relacionados con la actividad física y la percepción general de la salud en todos los grupos, pero con mayor intensidad en el sexo femenino. Se observaron relaciones estadísticamente significativas entre las áreas de vitalidad y actividad física, la capacidad vital forzada y los volúmenes pulmonares. También se encontraron relaciones entre la presión inspiratoria máxima, la presión espiratoria máxima, la ventilación voluntaria máxima, la capacidad inspiratoria con volumen circulante y el índice volumen circulante. Conclusiones: Se observaron un patrón restrictivo muy ligero y reducción de la fuerza muscular inspiratoria. Los ámbitos de la CVRS más afectados fueron los relacionados con la actividad física y la percepción general de la salud. La afectación muscular respiratoria contribuye a una alteración en las variables de la función pulmonar y al deterioro de la calidad de vida relacionada con la salud

Objective: To study lung function abnormalities and health-related quality of life (HRQL) in a group of patients diagnosed with generalized myasthenia gravis, and to analyze the relationship between these 2 sets of variables. Patients and methods: In a prospective study of 20 patients diagnosed with generalized myasthenia gravis, the following parameters were measured: spirometry, static lung volumes, breathing pattern, maximal respiratory pressures, and maximum voluntary ventilation. HRQL was assessed using the 36-item short form general health questionnaire (SF-36). Results: The mean (SD) age of the patients was 64 (11) years. Patients were classified into 2 groups depending on whether they had IIa (12 patients) or IIb (8 patients) type disease. A small decrease in total lung capacity (86%) and slight reductions in maximal inspiratory pressure (88%) and maximum voluntary ventilation (63% in group IIb) were observed. The HRQL domains most affected were those related to physical activity and self-perceived health status in all groups, although women were more affected. The scores relating to vitality and physical activity were found to be significantly associated with forced vital capacity and lung volumes. Tidal volume was associated with maximal inspiratory and expiratory pressures, inspiratory capacity, and maximum voluntary ventilation. The respiratory rate to tidal volume ratio was inversely associated with the first three of these variables. Conclusions: A very slight restrictive pattern and a reduction in inspiratory muscle strength were observed. The HRQL domains most affected were those related to physical activity and the patients' self-perceived health status. The weakness of the respiratory muscles contributes to the abnormalities observed in lung function and to the deterioration of health-related quality of life