Respiratory muscle training (RMT) has been shown to improve exercise tolerance during a wide range of exercise modalities and durations of activity (McConnell & Romer, 2004b). However, there is a limited amount of research characterising the influence of RMT in specific athletic populations, or examining any sport-specific factors that may influence the benefits of RMT. Hence, the purpose of this dissertation was to evaluate the application of RMT in competitive rowers and to explore methods of optimising this to rowing. Results: Inspiratory muscle training (IMT) increased inspiratory muscle strength (~20-29%; p < 0.05) and attenuated inspiratory muscle fatigue (~8-28%; p < 0.05) during time trial performance in club-level and elite rowers. However, only in the club-level oarsmen was IMT associated with a measurable improvement in rowing performance (2.7% increase in mean power; p < 0.05). Expiratory muscle training (EMT) provided no ergogenic effect, and concurrent EMT and IMT did not enhance performance above that seen with IMT alone. IMT loads performed at 60-70% of maximal inspiratory mouth pressure (PImax) were equivalent to the widely used 30 repetition maximum, which is higher than reported for non-rowers (Caine & McConnell, 1998a); further, a load of 60% PImax was sufficient to activate the inspiratory muscle metaboreflex, as evidenced by a time-dependent rise in heart rate (70.1 ± 13.2 to 98.0 ± 22.8 bpm; p < 0.05) and mean arterial blood pressure (92.4 ± 8.5 to 99.7 ± 10.1 mmHg; p < 0.05). Higher and lower inspiratory loads did not activate the metaboreflex. Assessments of flow, pressure and volume in rowing relevant postures revealed no significant impairments, but optimal function occurred in the most upright postures. Conclusions: These data support the application of IMT, but not EMT, in elite and sub-elite rowers, and suggest that a load of 60-70% of PImax provides metaboreflex activation during loading. Further, the data do not support a requirement to undertake IMT in rowing relevant postures.

Introdução. Pacientes portadores de diabetes mellitus tipo 2 (DM2) podem apresentar fraqueza da musculatura inspiratória. O efeito do treinamento muscular inspiratório (TMI) nesses pacientes ainda é desconhecido. Objetivos. Avaliar os efeitos do TMI sobre a força muscular inspiratória, a função pulmonar, a capacidade funcional e a modulação autonômica em pacientes com DM2 com fraqueza da musculatura inspiratória. Métodos. A pressão inspiratória máxima (PImáx) foi avaliada em uma amostra de 148 pacientes com DM2 da qual 25 pacientes com PImáx < 70% do previsto foram randomizados para um programa de 8 semanas de TMI diário (n=12) ou TMI-placebo (n=13). A PImáx, a função pulmonar, o consumo máximo de oxigênio e a variabilidade da freqüência cardíaca foram avaliados antes e após o TMI. Resultados. Do total de pacientes avaliados, 29,05% (43 pacientes) apresentaram fraqueza muscular inspiratória. O TMI aumentou significativamente a PImáx (118%) e a resistência muscular inspiratória (320%), sem alterar a função pulmonar, a capacidade funcional e a modulação autonômica. Conclusões. O TMI, em pacientes com DM2 e fraqueza dos músculos inspiratórios, aumentou significativamente a PImáx sem modificar a função pulmonar, a capacidade funcional e a modulação autonômica. / Introduction. Subject with type 2 diabetes mellitus (DM2) can present weakness of the inspiratory muscle. The effect of the inspiratory muscle training (IMT) in these patients still is unknown. Objectives. To evaluate the effect of the IMT on the inspiratory muscle force, the pulmonary function, the functional capacity and the autonômica modulation in patients DM2 with weakness of the inspiratory muscle. Methods. The maximum inspiratory pressure (PImáx) was evaluated in a sample of 148 patients with DM2 of which 25 patients with PImáx < 70% of the foreseen one had been randomizeds for a program of 8 weeks of daily IMT (n=12) or IMT-placebo (n=13). The PImáx, the function pulmonary, the VO2 and the variability of the cardiac frequency had been evaluated before and after the IMT. Results. Of the total of evaluated patients, 29.05% (43 patients) had presented inspiratory muscle weakness. The IMT significantly increased the PImáx (118%) and the inspiratory muscle resistance (320%), without modifying the function pulmonary, the exercise capacity and the modulation autonomic. Conclusions. The IMT in patients with DM2 and weakness of the inspiratory muscles increased the PImáx without modifying the function pulmonary, the exercise capacity and the modulation autonomic significantly.

Introdução. Pacientes portadores de diabetes mellitus tipo 2 (DM2) podem apresentar fraqueza da musculatura inspiratória. O efeito do treinamento muscular inspiratório (TMI) nesses pacientes ainda é desconhecido. Objetivos. Avaliar os efeitos do TMI sobre a força muscular inspiratória, a função pulmonar, a capacidade funcional e a modulação autonômica em pacientes com DM2 com fraqueza da musculatura inspiratória. Métodos. A pressão inspiratória máxima (PImáx) foi avaliada em uma amostra de 148 pacientes com DM2 da qual 25 pacientes com PImáx < 70% do previsto foram randomizados para um programa de 8 semanas de TMI diário (n=12) ou TMI-placebo (n=13). A PImáx, a função pulmonar, o consumo máximo de oxigênio e a variabilidade da freqüência cardíaca foram avaliados antes e após o TMI. Resultados. Do total de pacientes avaliados, 29,05% (43 pacientes) apresentaram fraqueza muscular inspiratória. O TMI aumentou significativamente a PImáx (118%) e a resistência muscular inspiratória (320%), sem alterar a função pulmonar, a capacidade funcional e a modulação autonômica. Conclusões. O TMI, em pacientes com DM2 e fraqueza dos músculos inspiratórios, aumentou significativamente a PImáx sem modificar a função pulmonar, a capacidade funcional e a modulação autonômica. / Introduction. Subject with type 2 diabetes mellitus (DM2) can present weakness of the inspiratory muscle. The effect of the inspiratory muscle training (IMT) in these patients still is unknown. Objectives. To evaluate the effect of the IMT on the inspiratory muscle force, the pulmonary function, the functional capacity and the autonômica modulation in patients DM2 with weakness of the inspiratory muscle. Methods. The maximum inspiratory pressure (PImáx) was evaluated in a sample of 148 patients with DM2 of which 25 patients with PImáx < 70% of the foreseen one had been randomizeds for a program of 8 weeks of daily IMT (n=12) or IMT-placebo (n=13). The PImáx, the function pulmonary, the VO2 and the variability of the cardiac frequency had been evaluated before and after the IMT. Results. Of the total of evaluated patients, 29.05% (43 patients) had presented inspiratory muscle weakness. The IMT significantly increased the PImáx (118%) and the inspiratory muscle resistance (320%), without modifying the function pulmonary, the exercise capacity and the modulation autonomic. Conclusions. The IMT in patients with DM2 and weakness of the inspiratory muscles increased the PImáx without modifying the function pulmonary, the exercise capacity and the modulation autonomic significantly.

Introdução. Pacientes portadores de diabetes mellitus tipo 2 (DM2) podem apresentar fraqueza da musculatura inspiratória. O efeito do treinamento muscular inspiratório (TMI) nesses pacientes ainda é desconhecido. Objetivos. Avaliar os efeitos do TMI sobre a força muscular inspiratória, a função pulmonar, a capacidade funcional e a modulação autonômica em pacientes com DM2 com fraqueza da musculatura inspiratória. Métodos. A pressão inspiratória máxima (PImáx) foi avaliada em uma amostra de 148 pacientes com DM2 da qual 25 pacientes com PImáx < 70% do previsto foram randomizados para um programa de 8 semanas de TMI diário (n=12) ou TMI-placebo (n=13). A PImáx, a função pulmonar, o consumo máximo de oxigênio e a variabilidade da freqüência cardíaca foram avaliados antes e após o TMI. Resultados. Do total de pacientes avaliados, 29,05% (43 pacientes) apresentaram fraqueza muscular inspiratória. O TMI aumentou significativamente a PImáx (118%) e a resistência muscular inspiratória (320%), sem alterar a função pulmonar, a capacidade funcional e a modulação autonômica. Conclusões. O TMI, em pacientes com DM2 e fraqueza dos músculos inspiratórios, aumentou significativamente a PImáx sem modificar a função pulmonar, a capacidade funcional e a modulação autonômica. / Introduction. Subject with type 2 diabetes mellitus (DM2) can present weakness of the inspiratory muscle. The effect of the inspiratory muscle training (IMT) in these patients still is unknown. Objectives. To evaluate the effect of the IMT on the inspiratory muscle force, the pulmonary function, the functional capacity and the autonômica modulation in patients DM2 with weakness of the inspiratory muscle. Methods. The maximum inspiratory pressure (PImáx) was evaluated in a sample of 148 patients with DM2 of which 25 patients with PImáx < 70% of the foreseen one had been randomizeds for a program of 8 weeks of daily IMT (n=12) or IMT-placebo (n=13). The PImáx, the function pulmonary, the VO2 and the variability of the cardiac frequency had been evaluated before and after the IMT. Results. Of the total of evaluated patients, 29.05% (43 patients) had presented inspiratory muscle weakness. The IMT significantly increased the PImáx (118%) and the inspiratory muscle resistance (320%), without modifying the function pulmonary, the exercise capacity and the modulation autonomic. Conclusions. The IMT in patients with DM2 and weakness of the inspiratory muscles increased the PImáx without modifying the function pulmonary, the exercise capacity and the modulation autonomic significantly.

Obstructive sleep apnea (OSA) is a disease characterized by nighttime airflow limitation, hypoxemia, arousal from sleep, and elevated sympathetic activity and blood pressure. With time, this nighttime dysfunction gives rise to daytime hypertension and a heightened risk for cardiovascular disease. Current treatment options for OSA are not always effective for all patients and the gold-standard intervention, continuous positive airway pressure, has discouraging compliance rates. The work set forth in this dissertation has as its focus a novel intervention for sleep apnea known as inspiratory muscle training (IMT). IMT improves respiratory function and cardiovascular health but has not been implemented previously as a treatment for OSA. As such, Study 1 implements IMT in individuals with mild and moderate OSA, with the objective of assessing the effects of training on the cardio- respiratory parameters of this disease. We randomly assigned 24 individuals with mild- moderate OSA into one of two groups: training vs. placebo, to assess the effects of 6 weeks of training on overnight polysomnography, subjective sleep quality, blood pressure, circulating inflammatory T cells, and plasma catecholamine content. Our results show IMT- related improvements in sleep quality, reduction in the number of arousals from sleep and in periodic limb movements following 6 weeks of training. Most important, IMT was associated with a significant reduction in systolic (~12 mmHg) and diastolic (~5 mmHg) blood pressure, relative to sleep apneics who undertook 6 weeks of placebo training. Additionally, individuals in the training group exhibited ~30% lower levels of sympathetic activity, as measured by plasma catecholamines, relative to placebo trained peers. The mechanism(s) that underlie the IMT-related reductions in blood pressure and sympathetic activity remain to be determined. However, in an effort to determine the precise respiratory stimulus that contributes to the results obtained in Study 1, we subsequently assessed the specific respiratory components of IMT to determine which component (large intrathoracic pressures and/or large lung volumes) likely contributes to the reduction in blood pressure in Study 1. The results of this study conducted in normotensive adults show that respiratory training that entails either large negative or positive intrathoracic pressures reduces systolic and diastolic blood pressure in healthy young adults. Importantly, neither the generation of large lung volumes alone nor performance of daily paced breathing is sufficient to lower blood pressure. Study 3 is a methodologic study that has as its focus upper airway electromyography (EMG) and the utility of assessing EMG activity across a range of conditions and breathing tasks in wakefulness. Because OSA traditionally has been viewed as the result of neuromuscular dysfunction of the upper airway that occurs during sleep, the aim of this work was to develop a "fingerprint" of healthy electromyographic activities during the day in healthy adults across a range of breathing tasks, body positions, and from two different muscle compartments of the upper airway. The findings from this study demonstrate regional differences in muscle activity that vary as a function of body position and task. These data from healthy subjects provide the basis of comparison for subsequent studies in individuals with obstructive sleep apnea.

The aim of this thesis was to evaluate the effect of exercise training and inspiratory muscle training and to describe pulmonary function, respiratory muscle strength, physical performance and health-related quality of life (HRQoL) following lung cancer surgery. Study I was a randomised controlled trial including 78 patients radically operated for lung cancer. The intervention group received 10 sessions of supervised exercise training in addition to home-based exercise; the control group was instructed on home-exercise alone. Supervised compared to non-supervised exercise training did not result in differences between groups in HRQoL, except for the SF-36 bodily pain domain four months after the surgery. No effects of supervised training were found for any outcome after one year. Study II was descriptive and was based on the study I sample. We evaluated the course of recovery of HRQoL and physical performance up to one year following surgery. All patients improved HRQoL and physical performance one year after the surgery, reaching values comparable to a reference healthy population. The walked distance was positively associated with the SF-36 domain for physical functioning. Study III was descriptive, included 81 patients and evaluated the influence of surgery on respiratory muscle strength, lung function and physical performance two weeks and six months after surgery. We found that respiratory muscle strength was not affected after the second postoperative week and that muscle-sparring thoracotomy did not deteriorate respiratory muscle strength, compared to video-assisted thoracic surgery. Compared to preoperative values, physical performance was recovered, whereas lung function remained reduced six months postoperatively. Study IV was a randomised controlled trial including 68 patients at high risk of developing postoperative pulmonary complications (PPC). This study evaluated the effects of two weeks of postoperative inspiratory muscle training in addition to breathing exercises and early mobilisation on respiratory muscle strength and the incidence of PPC. Additional inspiratory muscle training did not increase respiratory muscle strength, but improved postoperative oxygenation. Respiratory muscle strength was recovered in both groups two weeks postoperatively.

La commande de la ventilation chez l'humain est capable d'adaptation persistante qui repose sur des mécanismes de type LTP. Différentes techniques permettant l'induction de plasticité sont couramment utilisées mais leur application au contrôle ventilatoire n'a fait l'objet que de très peu de travaux.L'objectif de cette thèse est (1) examiner la possibilité d'induire des mécanismes de type LTP par la rTMS et la tsDCS en deux sites de la commande ventilatoire destinée au diaphragme, l'AMS et les métamères C3-C5 ; (2) évaluer les conséquences sur le profil ventilatoire en ventilation de repos et lorsque la ventilation est artificiellement contrainte. Nous avons examiné les effets d'un conditionnement inhibiteur appliqué par rTMS en regard de l'AMS sur l'excitabilité corticophrénique. Nous avons observé la présence d'une diminution persistante de cette excitabilité et en avons tiré la proposition qu'en ventilation de repos l'AMS augmente l'excitabilité de la commande ventilatoire à l'éveil. Nous avons alors considéré les conséquences de la rTMS sur la ventilation expérimentalement contrainte. Les modifications du profil ventilatoire induites par la rTMS sont en faveur d'une participation de l'AMS à la production ou au traitement de la copie d'efférence. Dans une 3ème étude, nous avons examiné les effets de la tsDCS au niveau C3-C5 sur l'excitabilité corticophrénique et sur le profil ventilatoire. L'augmentation de cette excitabilité et du volume courant nous a conduit à suggérer la possibilité d'induire une plasticité respiratoire au niveau spinal.L'ensemble de ces résultats nous permet d'envisager des perspectives thérapeutiques à l'utilisation de la rTMS et de la tsDCS. / A salient feature of the ventilatory control system is its ability to persistently adapt its behaviour. This stems from long-term plasticity mechanisms similar to those described for the neural control in general. Plasticity can be induced by various non-invasive stimulation techniques(e.g. rTMS, TDCS, tsDCS) that are commonly used but have not be systematically applied to ventilatory plasticity. The aim of this thesis is twofold: (1) to examine the possibility of inducing LTP by rTMS and tsDCS at two sites of the ventilatory control system, namely the SMA and the phrenic motoneurons: (2) to evaluate the impact of such plasticity on breathing pattern during spontaneous ventilation and inspiratory threshold loading. We examined the effects of an inhibitory rTMS paradigm applied to the SMA on corticophrenic excitability. We observed a persistent decrease in corticophrenic excitability and therefore proposed that the SMA participates in the increased resting state of the ventilatory motor system during wake. Then we considered the consequences of rTMS on breathing pattern during ITL. The corresponding modifications support a contribution of the SMA to the production or processing of an ventilatory efference copy. In a third study, we examined the effects of a tsDCS delivered to C3-C5 on the corticophrenic excitability and on the respiratory pattern. Increased corticophrenic excitability and tidal volume were observed. This suggests that respiratory plasticity takes place at the spinal level. Taken together, these results open the perspective of harnessing respiratory plasticity as a therapeutic tool in disorders altering the ventilatory command.

INTRODUÇÃO: Estudos prévios demonstram que pacientes com insuficiência cardíaca (IC) podem apresentar redução dinâmica na capacidade inspiratória (CI) durante o exercício associada à redução da capacidade aeróbia. Poucas informações estão disponíveis atualmente sobre se esta redução está relacionada a anormalidades da mecânica ventilatória ou à disfunção muscular inspiratória. OBJETIVOS: Comparar a atividade muscular inspiratória e a intensidade da dispneia durante o exercício em pacientes com IC estável que apresente (Grupo 1) ou não (Grupo 2) redução da CI durante o exercício. MÉTODOS: Foram avaliados 16 pacientes com IC clinicamente estáveis (11 homens, 30 ± 5% de fração de ejeção) e não obesos tratados de acordo com diretrizes baseadas em evidências, sem outras doenças sistêmicas ou evidência espirométrica de obstrução do fluxo aéreo (VEF1/CVF = 83 ± 5%). Os pacientes realizaram teste de exercício cardiopulmonar incremental com medidas seriadas de CI, percepção de dispneia (Borg) e monitoramento contínuo das pressões esofágica (Pes) e gástrica (Pga). A pressão transdiafragmática (Pdi) foi obtida a partir de Pga–Pges. As manobras de Sniff e pressão inspiratória máxima (PImax) foram comparadas em repouso e imediatamente após o exercício. RESULTADOS: Quatro pacientes (25%, Grupo 1) apresentaram redução da CI durante o exercício (-0,18 ± 0,01 vs 0,28 ± 0,05L, p < 0,05). Não houve diferença significativa entre os grupos na função pulmonar e variáveis ecocardiográficas, exceto por uma menor capacidade residual funcional no Grupo 1 (72 ± 9 vs 97 ± 17%; p < 0,05) e menor PImax no Grupo 2 (-101± 25 vs 67 ± 24 cmH2O, p < 0,05). Pes,Sniff (Grupo 1: -77,9 ± 8,7 a -79,6 ± 8,8; Grupo 2: -63,3 ± 4,8 a -66,3 ± 3,8 cmH2O) e Pdi,Sniff (Grupo 1: 116,3 ± 13,9 a 118,3 ± 14,2; Grupo 2: 92,3 ± 5,6 a 98,0 ± 6,0 cmH2O) não diminuíram significativamente com o exercício, assim como Pes,PImax (Grupo 1: -90,5 ± 6,2 a 90,0 ± 9,7; Grupo 2: -64,5 ± 7,3 a 62,3 ± 7,5 cmH2O) e Pdi,PImax (Grupo 1: 140,0 ± 14,0 a 129,3 ± 15,1; Grupo 2: 102,1 ± 15,4 a 90,4 ± 11,4 cmH2O). Apesar de Pga e Pdi terem reduzido ao longo das manobras seriadas de CI durante o exercício no Grupo 1, a Pes não diferiu entre os grupos. A dispneia também foi semelhante entre os grupos. Por fim, o Grupo 1 apresentou volume de reserva inspiratório menor que o Grupo 2 somente no pico do exercício (0,90 ± 0,08 vs 1,47 ± 0,21L; p <0,05). CONCLUSÃO: A redução da CI durante o exercício em alguns pacientes com IC parece ser acompanhada por queda da força diafragmática que é totalmente compensada pelos músculos inspiratórios acessórios. O Grupo 1 apresentou dispneia similar em relação ao grupo 2, provavelmente, pelo fato de o exercício ter sido interrompido antes de os pacientes atingirem limiares ventilatórios críticos para expansão do volume corrente. / BACKGROUNG: It has been described that patients with chronic heart failure (CHF) may present with dynamic reduction in inspiratory capacity (IC), which was associated with low peak aerobic capacity. Little information is currently available about whether this reduction is related to respiratory mechanics abnormalities or to impaired inspiratory muscle function. OBJECTIVE: To compare inspiratory muscle activity and intensity of dyspnea during exercise in stable patients with CHF presenting (Group 1) or not (Group 2) with dynamic reduction in IC. METHODS: We studied 16 clinically stable, non obese patients with CHF (11 males, 30 ± 5% ejection fraction) treated according to current evidence-based guidelines with no other systemic diseases or spirometric evidence of airflow obstruction (FEV1/FVC = 83 ± 5%). They performed incremental cardiopulmonary cycle exercise test with serial measurements of IC, dyspnea rating (Borg), and continuous monitoring of esophageal (Pes) and gastric (Pga) pressures. Transdiaphragmatic pressure (Pdi) was obtained from Pga–Pes. Sniff and maximal inspiratory pressure (MIP) maneuvers were compared at rest and immediately post exercise. RESULTS: Four patients (25%, Group 1) showed IC reduction during exercise (-0.18 ± 0.02 vs 0.28 ± 0.19L; p<0.05). There were no significant between-groups differences in lung function and echocardiographic variables, except for a lower functional residual capacity (72 ± 9 vs 97 ± 17%; p < 0.05) in Group 1 and a lower MIP (-101 ± 25 vs 67 ± 24 cm H2O; p < 0.05) in Group 2. Pes,Sniff (Group 1: -77.9 ± 8.7 to -79.6 ± 8.8; Group 2: -63.3 ± 4.8 to -66.3 ± 3.8 cmH2O) and Pdi,Sniff (Group 1: 116.3 ± 13.9 to 118.3 ± 14.2; Group 2: 92.3 ± 5.6 to 98.0 ± 6.0 cmH2O) did not significantly decrease with exercise. Despite Pga and Pdi felt along successive IC maneuvers in Group 1, Pes did not differ between groups. Dyspnea was also similar between groups. Finally, inspiratory reserve volume was lower in Group 1 only at peak exercise (0.90 ± 0.08 vs 1.47 ± 0.21L; p <0.05). CONCLUSIONS: Decrements in exercise IC in some patients with CHF seems accompanied by a dynamic impairment in diaphragm strength that is fully compensated by other inspiratory rib cage muscles. Group 1 presented similar dyspnea compared to Group 2 probably because they stopped exercise before reaching critical ventilatory constraints to tidal volume expansion.

Made available in DSpace on 2014-06-11T19:23:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-17Bitstream added on 2014-06-13T18:50:43Z : No. of bitstreams: 1 gimenes_c_me_botfm.pdf: 464422 bytes, checksum: 627314a0c5f4867528442a8ec3866145 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A cirurgia de revascularização miocárdica (RM) envolve a cavidade torácica e, conseqüentemente, as complicações pulmonares são freqüentemente observadas. Fatores pré e intra-operatórios, como idade avançada, doença pulmonar, tabagismo, circulação extracorpórea (CEC), esternotomia, entre outros, contribuem para o prejuízo da função pulmonar. No período pós-operatório o paciente está predisposto a apresentar atelectasias e infecções respiratórias. Além disso, ocorrem alterações na mecânica respiratória, com diminuição da força dos músculos respiratórios e do pico de fluxo expiratório. Relacionar as variáveis clínicas e laboratoriais pré e intra-operatórias com o grau de redução das pressões respiratórias máximas e do pico de fluxo expiratório em pacientes submetidos à cirurgia de RM. Foram estudados 61 pacientes que foram submetidos à cirurgia de RM, sob CEC, esternotomia mediana, e mantidos em ventilação mecânica por período máximo de 24 horas. No dia anterior à cirurgia, foram realizadas entrevista, consulta ao prontuário, e avaliação das pressões respiratórias (pressões inspiratória e expiratória máximas, PImáx e PEmáx), por meio da manovacuometria e medida do pico de fluxo expiratório (PFE). No 5° dia de pósoperatório, foram repetidas as medidas de PImáx, PEmáx e PFE. A análise estatística foi realizada por meio de teste t de Student, correlação linear de Pearson e modelo de regressão logística. Os resultados são discutidos no nível de significância de 5%. Características gerais: idade, 63±10 anos; sexo masculino, 67%; IMC, 28,0±3,8 Kg/m2; hemoglobina (Hb), 12,8±1,7 g/dl; prevalência de: infarto prévio 67%, hipertensão arterial sistêmica 75%, diabetes mellitus 31%, Resumo 57... / The coronary artery bypass grafting (CABG) affects the thoracic cavity and consequently pulmonary complications are frequently observed. Preand intra-operative factors as advanced age, pulmonary disease, smoking, cardiopulmonary bypass (CPB), sternotomy, among others, contribute to the reduction of lung function. In the postoperative period, patients are predisposed to atelectasis and respiratory infections. In addition, changes in respiratory mechanics, with reduction of maximal respiratory pressures and peak expiratory flow, may occur. To compare the pre and intra-operative clinical and laboratory factors with degree of reduction of maximal respiratory pressures and peak expiratory flow in patients undergoing surgery for CABG. Sixty-one patients underwent surgery for CABG under CPB, median sternotomy, and mechanical ventilation for a period of up to 24 hours, were studied. In the day before surgery, they were interviewed and submitted to assessment of maximal respiratory pressures (maximal inspiratory and expiratory pressures, MIP and MEP) through manovacuometry and measurement of peak expiratory flow (PEF). On the fifth day after surgery, measurements of MIP, MEP, and PEF were repeated. Student's t test, Pearson's linear, and logistic regression were used to statistical analysis. Results are discussed in the significance level of 5%. General: age, 63±10 years; male, 67%; BMI, 28.0±3.8 kg/m2; hemoglobin (Hb), 12.8±1.7 g/dl; prevalence of: previous infarction 67%, systemic arterial hypertension 75%, diabetes mellitus 31%, dyslipidemia 64%, and smoking 25%. Patients with class III angina showed greater reduction of MIP compared to Abstract 60 class II (33±15% vs. 22±13%, p=0.01). COPD patients had greater reduction in maximal respiratory pressures. The higher age individuals had the lower values of MEP and PEF ...(Complete abstract click electronic access below)

Introdução: A redução da capacidade inspiratória (CI) induzida pelo exercício observada em alguns pacientes com hipertensão arterial pulmonar (HAP) poderia potencialmente ser influenciada por disfunção muscular respiratória. Objetivos: Investigar se há alguma relação entre CI e força muscular respiratória antes e após o exercício máximo e estudar o papel da pressão muscular respiratória e da CI na dispneia e na capacidade de exercício em pacientes com HAP. Métodos: 27 pacientes com HAP e 12 controles saudáveis pareados foram comparados. Todos os participantes foram submetidos a teste de exercício cardiopulmonar (TECP) com determinação seriada da CI. As pressões inspiratória e expiratória máximas (PImáx e PEmáx, respectivamente) foram medidas antes, no pico e após o exercício. Resultados: Os pacientes tiveram menor volume expiratório forçado no primeiro segundo (VEF1), capacidade vital forçada (CVF) (com relação VEF1/CVF semelhante) e capacidade aeróbia máxima e maior dispneia no exercício. A PImáx e a PEmáx foram significativamente menores nos pacientes com HAP que nos controles. Entretanto, a variação pós exercício em relação ao repouso não foi significativamente diferente nos dois grupos. Os pacientes apresentaram redução significativa da CI do repouso ao pico do exercício em comparação aos controles. 17/27 pacientes (63%) apresentaram redução da CI durante o exercício. Considerando-se apenas os pacientes, não houve associação entre CI e PImáx ou PEmáx (pré, pós exercício ou mudança do repouso). Comparando-se os pacientes com e sem redução da CI, não houve diferença na proporção de pacientes que apresentaram redução da PImáx (41 vs 44%) ou da PEmáx (76 vs 89%) após o exercício. Da mesma forma, nenhuma diferença na PImáx ou PEmáx foi observada no exercício comparando estes subgrupos. Conclusões: Em resumo, a força muscular respiratória foi significativamente menor em pacientes com HAP em comparação com controles e uma proporção significativa de pacientes com HAP apresentaram redução da CI durante o exercício. No entanto, não foram observadas associações entre CI e alterações de força muscular respiratória com o exercício, sugerindo que ocorra verdadeira hiperinsuflação dinâmica. Além disso, o único parâmetro relacionado com a dispneia induzida pelo exercício foi a CI no repouso e com capacidade aeróbia no pico foi a magnitude da redução da PEmáx após o exercício. / Rationale: The exercise induced inspiratory capacity (IC) reduction observed in some patients with pulmonary arterial hypertension (PAH) could potentially be influenced by respiratory muscle dysfunction. Aims: To investigate if there is any relationship between IC and respiratory muscle strength before and after maximal exercise and to study the contribution of respiratory muscle pressure and IC in exercise dyspnea and capacity in PAH patients. Methods: 27 patients with PAH and 12 healthy matched controls were compared. All participants underwent cardiopulmonary exercise test (CPET) with serial IC measurements. Inspiratory and expiratory maximal mouth pressure (PImax and PEmax, respectively) were measured before and at peak/post exercise. Results: Patients had lower forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) (with similar FEV1/FVC ratio) and peak aerobic capacity and higher exercise dyspnea. PImax and PEmax were significantly lower in PAH patients compared to controls. However, post exercise variations from rest were not significant different in either group. Patients presented significant rest-to-peak reduction in IC compared to controls. 17/27 patients (63%) exhibited IC reduction during exercise. Considering only patients, there was no association between IC and PImax or PEmax (pre, post exercise or change from rest). Comparing patients with and without IC reduction, there was no difference in the proportion of patients presenting inspiratory (41 vs 44%) or expiratory (76 vs 89%) pressure reduction after exercise, respectively. In the same way, no difference in both inspiratory and expiratory respiratory pressure change with exercise was observed comparing these subgroups. Conclusions: In summary, respiratory muscle strength was significantly lower in PAH patients compared to controls and a significant proportion of PAH presented IC reduction during exercise. Nonetheless, no associations between IC and respiratory muscle strength changes with exercise were observed, suggesting a true dynamic lung hyperinflation. Additionally, the only parameter associated with exercise induced dyspnea was resting IC and with peak aerobic capacity was the magnitude of PEmax reduction after exercise.