No description available.

No description available.

Thesis (M.S.)--Humboldt State University, 2005. / Includes bibliographical references (leaves 37-43). Also available via Humboldt Digital Scholar.

Master of Science / Department of Kinesiology / Craig A. Harms / Diaphragmatic fatigue is known to limit endurance performance during heavy exercise in humans. Previous reports have shown that diaphragmatic fatigue is reduced in rats with N-acetylcysteine (NAC; a nonspecific antioxidant) infusion, suggesting that oxidative stress contributes to this fatigue. However, it is not known if oral supplementation of NAC will reduce respiratory muscle fatigue during heavy exercise in humans. Therefore, the purpose of this study was to determine the effect of an acute oral dose of NAC on respiratory muscle fatigue during whole body heavy exercise. Eight healthy, non-smoking men (22+/-2 yrs), with no history of cardiovascular or lung disease, completed baseline pulmonary function tests followed by an incremental cycle VO[subscript 2peak] test. A randomized, double blind crossover design was then used where subjects were given either placebo (PLA) or NAC (1800 mg) 45 min prior to a 30 minute constant load (85% VO[subscript 2peak]) discontinuous (six-five minute stages) or continuous (cycle until volitional exhaustion) exercise test. Tests were separated by approximately one week. Maximum pressures (inspiratory, PImax; expiratory, PEmax) and venous blood samples (plasma lactate and total plasma glutathione) were made prior to- and following each 5-min of exercise in discontinuous tests and pre- and post-exercise in continuous tests. Subject's VO[subscript 2peak] was 43+/-5 ml/kg/min. There was no difference (p>0.05) in PImax between NAC (127.9+/-34.1 cmH[subscript2]O) or PLA (134.1+/-28.1 cmH2O) at rest. During exercise, PImax was significantly lower ([similar to]14%) in 6 of 8 subjects with PLA compared to NAC at minutes 25 and 30 of the discontinuous test indicating respiratory muscle fatigue. With NAC, PImax did not change (p>0.05) from rest throughout exercise indicating no respiratory muscle fatigue. There was no difference (p>0.05) in PEmax, plasma glutathione, lactate, oxygen uptake (VO[subscript 2]), ventilation (VE), heart rate (HR), or rating of perceived exertion between PLA and NAC at rest or during exercise. Time to exhaustion was not different (p>0.05) during the continuous tests (PLA: 1263 + 334 sec; NAC: 1047 + 136 sec). These results suggest that an acute dose of NAC reduces respiratory muscle fatigue during high intensity exercise but does not alter other ventilatory or metabolic indices. The significance of this reduced respiratory muscle fatigue with NAC on whole body exercise performance remains to be determined.

No description available.

Ten well trained cyclists were studied and compared with 12 untrained subjects from a previous study to determine the effects of a high intensity, constant workload bout of cycling on maximum expiratory pressure (Pe_max). Subjects completed a graded exercise test on a Monark cycle ergometer while expired gases were collected to determine maximal oxygen consumption (VO_2max). Subjects then returned on a second day when measurements of each subject's Pe_max, were made prior to riding at the workload corresponding to 90% of their VO_2max until exhaustion. Measurements of expiratory pressure (Pe) were then made immediately post exercise (Pe_IPE), one minute post exercise (Pe_1MIN), three minutes post exercise (Pe_3MIN), and five minutes post exercise (Pe_5MIN). Trained cyclists had a significantly higher Pe_max (x = 116.43 ± 7.76 mmHg) than did untrained subjects (x = 65.75 ± 7.09 mmHg). Also trained cyclists generated a higher absolute Pe throughout recovery than did the untrained subjects. Although expiratory pressure decreased after exercise in both groups, the relative change in Pe over the recovery period, expressed as a percentage of Pe_max, was not different between trained and untrained. Pe_IPE was decreased to 81.87% ± 3.12 of Pe_maxin trained subjects and 82.35% ± 2.85 in untrained subjects (p < .05), recovering somewhat at 1 minute to 89.19% ± 3.59 of Pema, in trained and to 87.74% ± 3.27 in untrained (p < .05) but did not recover to resting levels in either group. Pe_3MIN and Pe_5MIN remained at the same level as Pe_1MIN in both groups. Therefore, a high intensity, short term exercise bout caused expiratory pressure to be decreased in both trained and untrained subjects. / Master of Science

Η λειτουργία των αναπνευστικών μυών σε ασθενείς με Κυστική Ίνωση (ΚΙ) μπορεί να εκτιμηθεί με τη μέτρηση της μέγιστης εισπνευστικής πίεσης (Pimax), της μέγιστης εκπνευστικής πίεσης (Pemax), του δείκτη πίεσης-χρόνου των αναπνευστικών μυών (PTImus), του ρυθμού μυϊκής χαλάρωσης (MRR) και του μέγιστου ρυθμού αύξησης πίεσης (MRPD). Ο σκοπός αυτής της μελέτης ήταν να μελετήσει τους δείκτες εκτίμησης της λειτουργίας των αναπνευστικών μυών σε ασθενείς με ΚΙ και την πιθανή επίδραση σπιρομετρικών και διατροφικών διαταραχών στη λειτουργία των αναπνευστικών μυών στους ασθενείς αυτούς. Επίσης να μελετήσει την πιθανή επίδραση της αεροβικής άσκησης στη λειτουργία των αναπνευστικών μυών σε ασθενείς με ΚΙ. Μελετήθηκε η λειτουργία των αναπνευστικών μυών με μέτρηση των PTImus, Pimax, Pemax, MRR και MRPD σε 140 ασθενείς με ΚΙ και σε ομάδα ελέγχου 140 υγιών μαρτύρων αντίστοιχης ηλικίας και φύλου. Η εκτίμηση της αναπνευστικής λειτουργίας περιλάμβανε μέτρηση του βιαίως εκπνεόμενου όγκου αέρα σε 1 δευτερόλεπτο (FEV1), της βιαίως εκπνεόμενης χωρητικότητας (FVC) και της βιαίως εκπνεόμενης ροής μεταξύ του 25% και του 75% της ζωτικής χωρητικότητας (MEF25-75). Η διατροφική εκτίμηση περιλάμβανε μέτρηση της περιφέρειας μυών μέσου βραχίονα (MAMC), της δερματικής πτυχής τρικεφάλου (TST), της μυϊκής επιφάνειας του βραχίονα (UAMA) και του δείκτη μάζας σώματος (BMI). Οι Pimax και Pemax βρέθηκαν σημαντικά ελαττωμένες σε ασθενείς με ΚΙ συγκρινόμενες με την ομάδα ελέγχου (p<0.01 και p<0.001 αντίστοιχα). Ο δείκτης PTImus βρέθηκε σημαντικά αυξημένος σε ασθενείς με ΚΙ σε σχέση με τα υγιή άτομα της ομάδας ελέγχου (p<0.05). Ο δείκτης PTImus βρέθηκε σημαντικά αυξημένος σε ασθενείς με ΚΙ και επηρεασμένους σπιρομετρικούς δείκτες. Επιπλέον, σε ασθενείς με ΚΙ ο δείκτης PTImus βρέθηκε να παρουσιάζει σημαντική αρνητική συσχέτιση με το δείκτη UAMA (p<0.05). Οι ασθενείς με ΚΙ και χαμηλές τιμές BMI δεν εμφάνισαν σημαντικά αυξημένες τιμές PTImus. Ο δείκτης MRR κατά την εκτέλεση δοκιμασίας Pemax (p<0.05) και ο δείκτης MRPD κατά την εκτέλεση δοκιμασίας Pemax (p<0.005) ήταν σημαντικά επηρεασμένοι σε ασθενείς με ΚΙ σε σχέση με την ομάδα ελέγχου. Οι ασκούμενοι ασθενείς με ΚΙ εμφάνισαν υψηλότερες τιμές μέγιστων αναπνευστικών πιέσεων και χαμηλότερες τιμές του δείκτη PTImus σε σχέση με μη ασκούμενους ασθενείς με ΚΙ. Συμπερασματικά, αυτή η μελέτη κατέδειξε ότι οι ασθενείς με ΚΙ εμφανίζουν υψηλότερες τιμές PTImus σε σχέση με το γενικό πληθυσμό. Ασθενείς με επηρεασμένους σπιρομετρικούς δείκτες όπως οι FEV1,FVC and MEF25-75, και διατροφικούς δείκτες όπως ο UAMA εμφανίζουν υψηλότερες τιμές PTImus σε σχέση με ασθενείς με φυσιολογικούς ή λιγότερο επηρεασμένους διατροφικούς και σπιρομετρικούς δείκτες. Η αεροβική άσκηση πιθανόν να επιδρά ευεργετικά στη διατήρηση της ισχύος των αναπνευστικών μυών σε ασθενείς με ΚΙ. / Respiratory muscle function in patients with Cystic Fibrosis (CF) can be assessed by measurement of maximal inspiratory pressure (Pimax), maximal expiratory pressure (Pemax), pressure time index of the respiratory muscles (PTImus), muscle relaxation rate (ΜRR) and maximum rate of pressure development (MRPD). This study aimed to examine respiratory muscle function indices in CF and the possible effect of pulmonary function and nutrition abnormalities to respiratory muscle performance, in patients with CF, as well as to investigate the possible effect of aerobic exercise in respiratory muscle function in CF. Respiratory muscle function by measurement of PTImus, Pimax, Pemax, MRR and MRPD was assessed in 140 CF patients and a control group of 140 healthy subjects matched as possible for age and gender. Pulmonary function evaluation consisted of forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC) and maximal expiratory flow between 25 and 75% of VC (MEF25-75). Nutritional assessment consisted of mid arm muscle circumference (MAMC), triceps skinfold thickness (TST), upper arm muscle area (UAMA) and body mass index (BMI). Pimax and Pemax were significantly lower in CF patients compared to the control group (p<0.01 and p<0.001 respectively). PTImus in CF patients compared to healthy controls was significantly increased (p<0.05). PTImus was significantly higher in CF patients with impaired pulmonary function. Furthermore, in CF patients, PTImus was significantly negatively related to UAMA (p<0.05). Patients with low BMI values did not have significantly higher PTImus values. MRR during Pemax (p<0.05) and MRPD during Pemax (p< 0.005) were significantly altered in CF compared to the control group. Exercising CF patients maintained higher maximal respiratory pressures and lower PTImus values compared to non-exercising patients. In conclusion this study demonstrated that CF patients exhibit higher PTImus values compared to the healthy population. Patients with affected pulmonary function parameters, such as FEV1, FVC and MEF25-75, and nutrition parameters such as UAMA exhibit higher PTImus values compared to CF patients with normal or less affected pulmonary function and nutrition indices. Exercise might exert a beneficial effect on respiratory muscle strength in patients with CF.

Bibliography: leaves 315-366. / 368 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Assesses the action of dimethylxanthines on the contractility of respriatory and quadriceps femoris muscle in normal subjects and in patients at risk of respiratory muscle fatigue, using accepted techniques. / Thesis (M.D.)--University of Adelaide, Faculty of Medicine, 1992

A Distrofia Muscular de Duchenne (DMD) é uma doença genética neuromuscular hereditária, ligada ao cromossomo X, sendo encontrada em seres humanos do sexo masculino em uma taxa de 1 para cada 3500 neonatos. Essa doença muscular é descrita também em outras espécies como o camundongo distrofico (Mdx), cães golden retriever com distrofia muscular GRMD e gatos com distrofia muscular hipertrófica felina (HFMD), os quais apresentam sintomas semelhantes à DMD e por esta razão tem sido amplamente utilizados como modelos experimentais para estudos. Portanto o objetivo deste estudo é avaliar a mobilidade do diafragma, os ciclos respiratórios e a expansão da caixa torácica de cães GRMD afetados e portadores, uma vez que a insuficiência respiratória é a principal causa de mortes em indivíduos acometidos. Para este estudo utilizou-se de avaliação ultrassonográfica dos muscúlos respíratórios (diafragma e intercostais), análises clínicas, e um acompanhamento de análises hematológicas. Como resultado obtido, o movimento de inspiração, expiração e platô, que compõe a mobilidade diafragmática, foi menor no grupo afetado do que nos controles. A fase de platô neste grupo (GRMD) é quase inexistente, indicando que o diafragma destes animais permanece em uma constante movimentação. A frequência respiratória foi 26,93 por minuto para o grupo controle e 15,5 por minuto para o grupo afetado, o qual se encontra abaixo do padrão normal. A movimentação dos m. intercostais apresentou expiração e inspiração respectivamente de: 8,99mm e 8,79mm para o grupo controle e 7,42mm e 7,40mm para o grupo afetado, mostrando que os indivíduos do grupo afetado tem uma menor expansão da caixa torácica e possivelmente um distúrbio na ventilação pulmonar. Conclui-se que a metodologia aplicada neste estudo é um meio viável de acompanhamento e avaliação do sistema respiratório no modelo GRMD, podendo ser adaptado futuramente em outros modelos experimentais da distrofia muscular. / The Duchenne Muscular Dystrophy (DMD) is a genetic neuromuscular disease, linked to chromosome X and is found in human males at a rate of 1 in every 3,500 newborns. This muscle disease is also described in other species such as mouse dystrophic (Mdx), golden retriever dogs with muscular dystrophy GRMD and cats with hypertrophic feline muscular dystrophy (HFMD), which present symptoms similar to DMD and for this reason has been widely used as experimental models for studies. Therefore the objective of this study is to evaluate the mobility of the diaphragm, the respiratory cycles and the expansion of the rib cage GRMD affected dogs and carriers, since respiratory failure the leading cause of death in affected individuals. For this study we used ultrasound evaluation of respiratory muscles (diaphragm and intercostal), clinical analysis, and monitoring of hematological analysis. As a result, the movement of inspiration, expiration and plateau, which comprises the diaphragmatic mobility was lower in the affected group than in controls. The plateau phase in this group (GRMD) is almost nonexistent, indicating that these diaphragm remains in a constant movement. Respiratory rate was 26.93 per minute for the control group and 15.5 minutes for the affected group, which is below the normal standard. The movimentation of the m. intercostal presented expiration and inspiration respectively: 8.99 mm and 8.79 mm for the control group and 7.42 mm and 7.40 mm for the affected group, showing that individuals in the affected group has a lower expansion of the rib cage and possibly a disturbance pulmonary ventilation. It is concluded that the methodology applied in this study is a viable means of monitoring and evaluation of the respiratory system in GRMD model and can be adapted in the future in other experimental models of muscular dystrophy.

INTRODUÇÃO: Existe uma dúvida na literatura médica se a monitorização respiratória do paciente crítico internado na Unidade de Terapia Intensiva contribuiria para melhora de seu prognóstico. OBJETIVO: Avaliar de maneira prospectiva se a mensuração de parâmetros respiratórios na admissão dos pacientes em ventilação espontânea na Unidade de Terapia Intensiva estaria relacionada com a necessidade de suporte ventilatório, duração da internação dos pacientes na UTI e com a mortalidade hospitalar. MÉTODOS: Foram avaliados prospectivamente 195 pacientes admitidos respirando espontaneamente (37,4% do total das admissões no período do estudo) na Unidade de Terapia Intensiva Adultos do Hospital Israelita Albert Einstein. No momento da admissão, foram medidos o VC espontâneo, a FR, a Pimax, a Pemax, FiO2, SpO2 , FC e foi investigado se o paciente apresentava causa pulmonar para a insuficiência respiratória. Os pacientes foram acompanhados até a alta hospitalar ou óbito. Um modelo de regressão logística por etapas progressivas e um modelo de regressão linear múltipla foram aplicados para avaliação das associações entre os parâmetros mensurados à entrada dos pacientes na UTI e a necessidade de suporte ventilatório, tempo de internação na UTI e mortalidade intrahospitalar. RESULTADOS: A média de idade dos 195 pacientes foi de 62,36±18,67, 77 mulheres. Trinta dos 195 pacientes necessitaram de suporte ventilatório (15,38%) e 20 pacientes morreram durante sua internação no hospital (10,25%). O tempo médio de internação na UTI foi de 5,1±5,8 dias. O modelo de regressão logística selecionou a Pimax (OR=1,04, p=0,018), doença respiratória primária (OR=2,8, p=0,036), FC (OR=1,03, p=0,022) e FiO2 (OR=1,04, p=0,043) como as variáveis relacionadas à necessidade de suporte ventilatório e o volume corrente espontâneo inicial (OR=0,92, p=0,000) como a variável relacionada à mortalidade intrahospitalar. O modelo de regressão linear múltipla selecionou a FC (Coeficiente=0,005, p=0,000), FR (Coeficiente =0,009, p=0,004), VC (Coeficiente = - 0,006, p=0,000) e sexo (Coeficiente =0,128, p=0,009) como as variáveis relacionadas ao tempo de internação na UTI. CONCLUSÃO: Em pacientes admitidos na UTI respirando espontaneamente, uma FC aumentada, necessidade de altas FiO2, Pimax diminuída e a presença de doença respiratória primária estiveram relacionadas com necessidade de suporte ventilatório. Pacientes do sexo masculino, com uma FC aumentada, FR aumentada e um baixo VC espontâneo apresentaram tempo de internação prolongado na UTI. A mensuração de VC espontâneo diminuído à admissão na UTI esteve fortemente relacionada a um aumento da mortalidade hospitalar. / INTRODUCTION: There is a doubt in the medical literature if the patients respiratory monitoring at ICU admission could improve their prognosis. OBJECTIVE: To measure respiratory parameters in patients admitted at ICU in spontaneous ventilation and relate them to the necessity of ventilatory support, length of ICU stay and hospital mortality. METHODS: We prospectively evaluated 195 patients admitted to the Adult ICU of the Albert Einstein Hospital in spontaneous ventilation (37.4% of total study period admissions). At ICU entry, we measured tidal volume (TV), respiratory rate (RR), maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), FiO2, SpO2, heart rate (HR) and we verified if the patient had a primary pulmonary disease. The patients were followed till hospital discharge or death. A stepwise logistic regression and multiple linear regression models were built to evaluate the relation of the respiratory parameters at ICU entry and the necessity of ventilatory support, ICU length of stay and intra-hospital mortality. RESULTS: The 195 patients mean age was 62.36±18.67, 77 females. Thirty of 195 patients needed ventilatory support (15.38%) and 20 died in the hospital (10.25%). The mean ICU length of stay was 5.1±5.8 days. The logistic regression model selected MIP (OR=1.04, p=0.018), primary respiratory disease (OR=2.8, p=0.036), HR (OR=1.03, p=0.022) and FiO2 (OR=1.04, p=0.043) as the variables related to the necessity of ventilatory support and the initial TV (OR=0.92, p=0.000) as the variable related to intra-hospital mortality. The multiple linear regression model selected the HR (Coefficient=0.005, p=0.000), RR (Coefficient =0.009, p=0.004), VT (Coefficient = - 0.006, p=0.000) and sex (Coefficient =0.128, p=0.009) as the variables related to the ICU length of stay. CONCLUSION: In spontaneous ventilated patients at ICU admission, a higher HR, higher FiO2, a lower MIP and a primary respiratory diagnosis were related to the necessity of ventilatory support. Male patients with a higher HR, higher RR and lower TV had a prolonged ICU length of stay. The initial measurement of a low spontaneous TV was strongly related to an increase in hospital mortality.