Inspiratory muscle weakness is associated with autonomic cardiovascular dysfunction in patients with type 2 diabetes mellitus.

INTRODUCTION: Diabetic autonomic neuropathy is a complication of diabetes mellitus (DM) that can cause cardiovascular and respiratory abnormalities. The association between respiratory muscle weakness and autonomic cardiovascular neuropathy has not yet been studied. The aims of the present study were to assess respiratory muscle strength, pulmonary function, and heart rate (HR) variability in diabetic patients with and without diabetic autonomic neuropathy. MATERIALS AND METHODS: Twenty-four patients with type 2 DM were divided into two groups: those without diabetic autonomic neuropathy (C group, n = 12); and those with diabetic autonomic neuropathy (DAN group, n = 12). We evaluated pulmonary function, maximum static inspiratory pressure (PImax), maximum static expiratory pressure (PEmax), and HR variability. RESULTS: The results of the pulmonary function tests were similar in both the groups. PImax was lower in the DAN group (80 ± 24 vs. 102 ± 24 cmH(2)O, p = 0.03), but PEmax was similar in both the groups. RR intervals (878 ± 122 vs. 743 ± 88 ms; p < 0.01), standard deviation of RR intervals (28 ± 11 vs. 14 ± 4 ms; p < 0.01) and squared root of the sum of successive differences of squared RR intervals (15 ± 6 vs. 8 ± 5 ms; p < 0.01) were higher in the C group. In the DAN group, resting HR was higher (82 ± 10 vs. 69 ± 9 bpm; p = 0.01) than in the C group. There was a positive correlation between PImax and RR intervals (r = 0.452, p = 0.02) and a negative correlation between PImax and resting HR (r = -0.482, p = 0.01), and PImax and DM duration (r = -0.463, p = 0.02). CONCLUSION: Patients with type 2 DM and autonomic neuropathy showed reduced respiratory muscle strength and less HR variability. Respiratory muscle weakness may be associated with autonomic dysfunction in these patients.

[Incentive spirometry with expiratory positive airway pressure brings benefits after myocardial revascularization].

BACKGROUND: Patients undergoing coronary artery bypass graft (CABG) surgery have higher risk to develop pulmonary complications (PCs) such as atelectasis, pneumonia and pleural effusion. These complications could increase the length of hospital stay, resources utilization and also are associated with reduced quality of life and functional capacity a long term. OBJECTIVE: To test if the use of incentive spirometry (IS) associated with expiratory positive airway pressure (EPAP), after CABG surgery improves dyspnea, effort perceived and quality of life 18 months after CABG. METHODS: Sixteen patients submitted to a CABG, were randomized to a control group (n=8) or IS+EPAP group (n=8). The protocol of IS+EPAP was applied in the immediate postoperative period and following for more 4 weeks in the patient's home. Eighteen months after CABG, the strength of the respiratory muscle, the functional capacity, the lung function, the quality of life and the level of physical activity were evaluated. RESULTS: After six minute walk test (6-MWT), the score of the dyspnea (1.6+/-0.6 vs 0.6+/-0.3, P<0.05) and the perceived effort (13.4+/-1.2 vs 9.1+/-0.7, P<0.05) were higher in the control group, when compared with the IS+EPAP group. In quality of life evaluation, the domain related to the physical aspects limitations was better in IS+EPAP group (93.7+/-4.1 vs 50+/-17, P<0.02). CONCLUSION: Patients that were submitted to IS+EPAP present reduction of dyspnea and lower effort sensation after the 6-MWT, and also a better quality of life 18 months after CABG.

Espirometria de incentivo com pressão positiva expiratória é benéfica após revascularização miocardio / Espirometría incentivada con presión positiva espiratoria es beneficiosa después de revascularización de miocardio / Incentive spirometry with expiratory positive airway pressure brings benefits after myocardial revascularization

FUNDAMENTO: Pacientes que são submetidos à cirurgia de revascularização do miocárdio (CRM) apresentam risco maior para desenvolver complicações pulmonares, como atelectasias, pneumonia e derrame pleural. Estas complicações podem aumentar o tempo de internação hospitalar, a necessidade de recursos financeiros e também se associam com a redução da qualidade de vida e da capacidade funcional a longo prazo. OBJETIVO: Testar se o uso de espirometria de incentivo (EI) associada com pressão positiva expiratória na via aérea (EPAP), após CRM melhora a dispneia, a sensação de esforço percebido e a qualidade de vida 18 meses após a CRM. MÉTODOS: Dezesseis pacientes submetidos a CRM foram randomizados para o grupo controle (n=8) ou para o grupo EI+EPAP (n=8). O protocolo de EI+EPAP foi realizado no período pós-operatório imediato e durante mais 4 semanas no domicílio. Dezoito meses após a CRM foram avaliadas a força da musculatura respiratória, a capacidade funcional, a função pulmonar, a qualidade de vida e o nível de atividade física. RESULTADOS: Após o teste de caminhada de seis minutos (TC6), o escore para dispneia (1,6±0,6 vs 0,6±0,3, P<0,05) e a sensação de esforço (13,4±1,2 vs 9,1±0,7, P<0,05) foram maiores no grupo controle comparado com o grupo EI+EPAP. Na avaliação da qualidade de vida, o domínio relacionado às limitações nos aspectos físicos foi melhor no grupo EI+EPAP (93,7±4,1 vs 50±17, P<0,02). CONCLUSÃO: Pacientes que realizam EI+EPAP apresentam menos dispneia e menor sensação de esforço após o TC6 e também melhor qualidade de vida 18 meses após a CRM.

BACKGROUND: Patients undergoing coronary artery bypass graft (CABG) surgery have higher risk to develop pulmonary complications (PCs) such as atelectasis, pneumonia and pleural effusion. These complications could increase the length of hospital stay, resources utilization and also are associated with reduced quality of life and functional capacity a long term. OBJECTIVE: To test if the use of incentive spirometry (IS) associated with expiratory positive airway pressure (EPAP), after CABG surgery improves dyspnea, effort perceived and quality of life 18 months after CABG. METHODS: Sixteen patients submitted to a CABG, were randomized to a control group (n=8) or IS+EPAP group (n=8). The protocol of IS+EPAP was applied in the immediate postoperative period and following for more 4 weeks in the patient's home. Eighteen months after CABG, the strength of the respiratory muscle, the functional capacity, the lung function, the quality of life and the level of physical activity were evaluated. RESULTS: After six minute walk test (6-MWT), the score of the dyspnea (1.6±0.6 vs 0.6±0.3, P<0.05) and the perceived effort (13.4±1.2 vs 9.1±0.7, P<0.05) were higher in the control group, when compared with the IS+EPAP group. In quality of life evaluation, the domain related to the physical aspects limitations was better in IS+EPAP group (93.7±4.1 vs 50±17, P<0.02). CONCLUSION: Patients that were submitted to IS+EPAP present reduction of dyspnea and lower effort sensation after the 6-MWT, and also a better quality of life 18 months after CABG.

FUNDAMENTO: Pacientes que son sometidos a cirugía de revascularización del miocardio (CRM) presenta mayor riesgo de desarrollar complicaciones pulmonares, como atelectasias, neumonía y derrame pleural. Estas complicaciones pueden aumentar el tiempo de internación hospitalaria, la necesidad de recursos financieros y también se asocian con la reducción de la calidad de vida y de la capacidad funcional a largo plazo. OBJETIVO: Probar si el uso de espirometría incentivada (EI) asociada con presión positiva espiratoria en la vía aérea (EPAP), después de la CRM mejora la disnea, la sensación de esfuerzo percibido y la calidad de vida 18 meses después de la CRM. MÉTODOS: Dieciocho pacientes sometidos a CRM fueron aleatorizados para el grupo control (n=8) o para el grupo EI+EPAP (n=8). El protocolo de EI+EPAP se realizó en el período postoperatorio inmediato y durante 4 semanas más en domicilio. Dieciocho meses después de la CRM se evaluaron la fuerza de la musculatura respiratoria, la capacidad funcional, la función pulmonar, la calidad de vida y el nivel de actividad física. RESULTADOS: Después del test de caminata de seis minutos (TC6), el score para disnea (1,6 ± 0,6 vs 0,6 ± 0,3, P < 0,05) y la sensación de esfuerzo (13,4 ± 1,2 vs 9,1 ± 0,7, P < 0,05) fueron mayores en el grupo control comparado con el grupo EI+EPAP. En la evaluación de la calidad de vida, el dominio relacionado con las limitaciones en los aspectos físicos fue mejor en el grupo EI+EPAP (93,7 ± 4,1 vs 50 ± 17, P < 0,02). CONCLUSIÓN: Pacientes que realizan EI+EPAP presentan menos disnea y menor sensación de esfuerzo después del TC6 y también mejor calidad de vida 18 meses después de la CRM.

Inspiratory muscle training improves oxygen uptake efficiency slope in patients with chronic heart failure.

PURPOSE: Inspiratory muscle training (IMT) improves exercise capacity and ventilatory responses to exercise in patients with chronic heart failure (CHF) with inspiratory muscle weakness (IMW). We analyzed the effects of IMT on the oxygen uptake efficiency slope (OUES) in this patient population. METHODS: Thirty-two CHF patients with IMW (maximal inspiratory pressure [PImax] < 70% of predicted) were randomly assigned to either a 12-week program of IMT (IMT, n = 16) or placebo-IMT (P-IMT, n = 16). PImax and OUES were obtained before and after the intervention. RESULTS: Inspiratory muscle training resulted in 115% increment in PImax (5.9 +/- 0.9 vs 12.7 +/- 0.9 kPa; P < .001) and in significant improvement in OUES (1,554 +/- 617 to 2,037 +/- 747 mL min O2/L min of minute ventilation; P = .001). There were no significant changes in the P-IMT group. There was a significant association between the changes in PImax and OUES (r = 0.82, P < .01). CONCLUSION: In CHF patients with IMW, IMT results in a significant increase in OUES.

Repercussões respiratórias da ventilação por cinta abdominal pneumática em ratos normais / Respiratory repercussions of the ventilation with abdominal pneumatic belt in normal rats

A Cinta Abdominal Pneumática (CAP) é um aparelho utilizado no mercado internacional com o objetivo de melhorar a função pulmonar de pacientes com seqüelas de poliomielite, doenças neuromusculares e lesão raquiomedular. O objetivo desta pesquisa foi avaliar os parâmetros respiratórios durante o uso da CAP através de um experimento com sete ratos normais. A variação da pressão intrapleural (Ppl), o tempo inspiratório (Ti), o tempo expiratório (Te), o tempo total do ciclo (Ttot), a freqüência respiratória (FR), a relação Ti/Ttot e o produto pressão tempo (PTP) foram mensurados com um transdutor de pressão no espaço pleural dos ratos, sem e com a CAP; a fim de se verificar seus reais efeitos fisiológicos. Os resultados mostraram que a CAP determina variação significativa na pressão pleural (p = 0,0489) o que melhora os volumes pulmonares e conseqüentemente a ventilação. A FR, Ti, Te, Ttot não sofreram alterações significativas. A variação da relação Ti/Ttot e do PTP não foi significativamente diferente, o que é vantajoso, uma vez que refletem aumento do gasto energético da respiração. Observou-se também assincronia durante seu uso, funcionando como estímulo inspiratório e não como auxílio expiratório.

The Abdominal Pneumatic Belt (APB) is a device used in the international market with the objective to improve the pulmonary function of patients with polio sequels, neuromuscular disorders and injury of spinal cord. This research considered an evaluation of the respiratory parameters during the use of the APB through an experiment with seven normal rats. The variation of the pleural pressure (Ppl), the inspiratory time (Ti), the expiratory time (Te), the total time of the cycle (Ttot), the respiratory frequency (FR), the Ti/Ttot relation and the pressure-time product (PTP) had been measure, through a transducer of pressure in the pleural space, without and with such equipment; in order to analyze its real physiological effect. The results had shown that the APB determines significant variation in the pleural pressure (p = 0,0489) what probably determines better pulmonary volumes and consequently better ventilation. The FR, Ti, Te and Ttot had not suffered significant alterations. The variation of the Ti/Ttot relation and the PTP is not significant too, what it would be advantageous, because it reflects increase of energy expense of the breath. It was observed an antagonism during the use, functioning as inspiratory stimulation and not as expiratory aid.

Incentive spirometry with expiratory positive airway pressure reduces pulmonary complications, improves pulmonary function and 6-minute walk distance in patients undergoing coronary artery bypass graft surgery.

BACKGROUND: The use of the incentive spirometry (IS) with expiratory positive airway pressure (EPAP) to prevent postoperative pulmonary complications (PPC) after coronary artery bypass graft (CABG) is not well established. This study sought to determine the effects of IS+EPAP after CABG. METHODS: Thirty-four patients undergoing CABG were randomly assigned to a control group or IS+EPAP group. Maximal respiratory pressures, pulmonary function test, 6-minute walk test and chest x-ray were performed at baseline as well as 1 week and 1 month after CABG. RESULTS: Maximal inspiratory pressure was significantly higher in the IS+EPAP group compared to controls at both 1 week and 1 month (P<.001). Maximal expiratory pressure was significantly higher at 1 month compared to 1 week in IS+EPAP group (P<.01). At 1 month, forced vital capacity and forced expiratory volume in 1 second was significantly higher in IS+EPAP compared to controls (P<.05). Inspiratory capacity was higher at 1 month in IS+EPAP group compared to controls (P<.05). The distance walked in 6-minute walk test was higher at 1 month in IS+EPAP group (P<.001) compared to controls. Lastly, radiological injury score at 1 week was lower in IS+EPAP compared to controls (P<.004). CONCLUSIONS: In patients undergoing CABG, IS+EPAP results in improved pulmonary function and 6-minute walk distance as well as a reduction in PPC.

O estresse oxidativo e o exercício físico em indivíduos HIV positivo / Oxidative stress and physical exercise in HIV positive individuals

A infecção pelo vírus da imunodeficiência humana (HIV) é acompanhada por alterações estruturais e funcionais relacionadas ao sistema imunológico. Além disso, o aumento do estresse oxidativo (EO) nos portadores do HIV, caracterizado por diminuição nos níveis de glutationa (GSH), aumentos na glutationa oxidada (GSSG), na razão GSSG/GSH e lipoperoxidação, bem como redução da atividade de enzimas antioxidantes - catalase, superóxido dismutase (SOD) e glutationa peroxidase (GPx) - é uma conseqüência da evolução dos pacientes infectados com HIV. As células do sistema imunológico necessitam de altas concentrações de antioxidantes para manter o balanço redox e preservar a sua integridade e função. Quando ocorre a depleção dos antioxidantes, há diminuição da resposta imunológica e aumento na replicação do HIV. O uso da terapia anti-retroviral combinada (TARV) melhorou significativamente a evolução clínica dos pacientes, porém, mesmo assim, alguns continuam apresentando EO aumentado e outros efeitos da TARV, como alterações no metabolismo lipídico e muscular. O treinamento físico é utilizado como intervenção não farmacológica nos pacientes infectados pelo HIV para proporcionar melhoria nos parâmetros antropométricos, aeróbios, musculares e psicológicos, porém, há carência de estudos sobre a sua utilização em relação ao estresse oxidativo. Nesta revisão, foram analisados os tópicos referentes ao estresse oxidativo nos pacientes HIV positivos e os possíveis benefícios do exercício físico na capacidade antioxidante. O treinamento físico é uma estratégia auxiliar para os pacientes, com ou sem uso da TARV, uma vez que melhora os aspectos cardiorrespiratórios, musculares, antropométricos e psicológicos sem induzir a imunossupressão. Referindo-se ao estresse oxidativo, infere-se, a partir dos dados em indivíduos HIV negativos, que o treinamento físico pode gerar adaptações que minimizam os efeitos deletérios provocados pelo EO através de melhorias nos ...

Human immunodeficiency virus (HIV) infection is characterized by functional and structural changes related to the immunological system. Moreover, increase in oxidative stress (OS) in HIV patients, characterized by a reduction in the glutathione (GSH) levels, increases in glutathione disulfide (GSSG), in the ratio GSSG/GSH and in lipid peroxidation, as well as a reduction in antioxidant enzymes - catalase, superoxid dismutase (SOD) and gluthatione peroxidase (GPx) - is a consequence of the evolution in HIV-infected patients. Higher levels of antioxidant activity are necessary to maintain the immunological system cells redox balance and preserve their function. In an antioxidant depleted state, there is a reduction in the immunological response and an increase in HIV replication. The use of highly active antiretroviral therapy (HAART) has improved the clinical evolution of these patients. However, some patients remain showing higher OS and other effects of HAART, such as changes in lipidic and muscle metabolism. Exercise training has been used as a non pharmacological treatment in HIV-infected patients to promote improvements in anthropometrics, aerobic, muscle and psychological outcomes; however, there are insufficient data about the effects of exercise training in OS. This review analyzes the topics related to the oxidative stress in HIV-infected patients and the possible benefits of the physical exercise in the antioxidant capacity. Physical training is a complementary procedure for the patients, with or without use of the HAART, since it improves the cardiorespiratory, muscle, anthropometrics and psychological performance without inducing immunodepression. In relation to oxidative stress, it is inferred, from the data obtained in non-HIV individuals, that the physical training could promote adaptations that minimize the deleterious effect induced by OS through improvements in the activity of the enzymatic and non-enzymatic antioxidant defenses.

Parasympathetic dysfunction is associated with baroreflex and chemoreflex impairment in streptozotocin-induced diabetes in rats.

This study explored physiological mechanisms of diabetic dysfunction in baroreceptors and chemoreceptors-mediated hemodynamic responses, and cholinergic neurotransmission in 30-day diabetic rats (n = 14) and controls (n = 14). Basal hemodynamic data and vagal response to electrical stimulation and methacholine injection were also evaluated. Muscarinic receptors were characterized using a radioligand receptor binding assay ([3H]N methylscopolamine). Experimental diabetes (50 mg/kg of STZ, i.v.) decreased systolic, diastolic, and mean arterial pressure and basal heart rate. Heart rate (HR) responses to vagal electrical stimulation (16, 32, and 64 Hz) were 15%, 11%, and 14% higher in diabetics vs non-diabetics, as were HR responses to methacholine injection (-130+/-24, -172+/-18, -206+/-15 bpm vs. -48+/-15, -116+/-12, -151+/-18 bpm, P < 0.05). Muscarinic receptor density was higher (267.4+/-11 vs 193.5+/-22 fmol/mg/prot, P < 0.05) in the atria of diabetic rats than in those of controls; the affinity was similar between groups. Diabetes-induced reduction of reflex responses to baro- (reflex bradycardia: -3.4+/-0.3 and -2.7+/-0.2 bpm/mm Hg; reflex tachycardia: -1.6+/-0.1 and -1.4+/-0.07 bpm/mm Hg, in control and diabetics, P < 0.05) and chemoreceptor stimulation, enhancement of HR responsiveness to cardiac vagal electrical stimulation and methacholine stimulation, plus an increase in the number of atrial muscarinic receptors indicates reduced parasympathetic activity, which is probably derived from central nervous system derangement.

Inspiratory muscle training in patients with heart failure and inspiratory muscle weakness: a randomized trial.

OBJECTIVES: This study sought to evaluate the effects of inspiratory muscle training in inspiratory muscle strength, as well as in functional capacity, ventilatory responses to exercise, recovery oxygen uptake kinetics, and quality of life in patients with chronic heart failure (CHF) and inspiratory muscle weakness. BACKGROUND: Patients with CHF may have reduced strength and endurance in inspiratory muscles, which may contribute to exercise intolerance and is associated with a poor prognosis. METHODS: Thirty-two patients with CHF and weakness of inspiratory muscles (maximal inspiratory pressure [Pi(max)] <70% of predicted) were randomly assigned to a 12-week program of inspiratory muscle training (IMT, 16 patients) or to a placebo-inspiratory muscle training (P-IMT, 16 patients). The following measures were obtained before and after the program: Pi(max) at rest and 10 min after maximal exercise; peak oxygen uptake, circulatory power, ventilatory oscillations, and oxygen kinetics during early recovery (VO2/t-slope); 6-min walk test; and quality of life scores. RESULTS: The IMT resulted in a 115% increment Pi(max), 17% increase in peak oxygen uptake, and 19% increase in the 6-min walk distance. Likewise, circulatory power increased and ventilatory oscillations were reduced. The VO2/t-slope was improved during the recovery period, and quality of life scores improved. CONCLUSIONS: In patients with CHF and inspiratory muscle weakness, IMT results in marked improvement in inspiratory muscle strength, as well as improvement in functional capacity, ventilatory response to exercise, recovery oxygen uptake kinetics, and quality of life.

Controle reflexo da pressão arterial no diabetes experimental / Reflex control of arterial pressure in experimental diabetes

Muitos dos mecanismos envolvidos nas alterações cardiovasculares do diabetes parecem representar adaptações funcionais e estruturais relacionadas à duração e à gravidade da doença. O controle da pressão arterial exercido por diferentes receptores periféricos está modificado precocemente e algumas modificações podem permanecer, independentemente do tratamento com insulina. O tamponamento das variações momento a momento da pressão arterial comandado pelos pressorreceptores arteriais está reduzido, assim como as respostas produzidas pela estimulação dos quimiorreceptores periféricos. Essas alterações representam comprometimento do ramo eferente (simpático e parassimpático), sem que se possa excluir mudanças no sistema nervoso central. As respostas do simpático renal às variações de volume estão bloqueadas e, no diabetes experimental, essa alteração pode caracterizar uma adaptação das respostas natriurética e diurética a essa condição. O endotélio parece ter papel relevante nas respostas hemodinâmicas sistêmica ou renal no diabetes. Algumas das alterações observadas no controle da pressão arterial em animais diabéticos podem ser revertidas pelo treinamento físico.