299 research outputs found

    Long-term oxygen therapy: state of the art

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    Improvement in self-reported exercise participation with the combination of tiotropium and rehabilitative exercise training in COPD patients

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    Steven Kesten1, Richard Casaburi2, David Kukafka3, Christopher B Cooper41Boehringer Ingelheim GmbH, Ingelheim, Germany; 2Harbor-UCLA Medical Center, Torrance, CA, USA; 3Northern Colorado Pulmonary Consultants PC, Fort Collins, CO, USA; 4UCLA School of Medicine, Los Angeles, CA, USABackground: Improvements in ventilatory mechanics with tiotropium increases exercise tolerance during pulmonary rehabilitation. We wondered whether tiotropium also increased physical activities outside of pulmonary rehabilitation.Methods: COPD patients participating in 8 weeks of pulmonary rehabilitation were studied in a randomized, double-blind, placebo-controlled trial of tiotropium 18 µg daily (tiotropium = 47, placebo = 44). Study drug was administered for 5 weeks prior to, 8 weeks during, and 12 weeks following pulmonary rehabilitation. Patients completed a questionnaire documenting participation in pre-defined activities outside of pulmonary rehabilitation during the 2 weeks prior to each visit. Patients who submitted an activity questionnaire at week 4 and on at least one subsequent visit were included in the analysis. For each patient, the number of sessions was multiplied with the duration of each activity and then summed to give overall activity duration.Results: Patients (n = 46) had mean age of 67 years, mean baseline FEV1 of 0.84 L (33% predicted). Mean (SE) increase in duration of activities (minutes during 2 weeks prior to each visit) from week 4 (prior to PR) to week 13 (end of PR) was 145 (84) minutes with tiotropium and 66 (96) minutes with placebo. The increase from week 4 to week 25 (end of follow-up) was 262 (96) and 60 (93) minutes for the respective groups. Increases in activity duration from week 4 to weeks 17, 21, and 25 were statistically significant with tiotropium. No statistical differences over time were observed within the placebo-treated group and differences between groups were not significant.Conclusions: Tiotropium appears to amplify the effectiveness of pulmonary rehabilitation as seen by increases in patient self-reported participation in physical activities.Keywords: activity, chronic obstructive pulmonary disease, exercise, pulmonary rehabilitation, tiotropiu

    Noninvasive prediction of Blood Lactate through a machine learning-based approach.

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    We hypothesized that blood lactate concentration([Lac]blood) is a function of cardiopulmonary variables, exercise intensity and some anthropometric elements during aerobic exercise. This investigation aimed to establish a mathematical model to estimate [Lac]blood noninvasively during constant work rate (CWR) exercise of various intensities. 31 healthy participants were recruited and each underwent 4 cardiopulmonary exercise tests: one incremental and three CWR tests (low: 35% of peak work rate for 15 min, moderate: 60% 10 min and high: 90% 4 min). At the end of each CWR test, venous blood was sampled to determine [Lac]blood. 31 trios of CWR tests were employed to construct the mathematical model, which utilized exponential regression combined with Taylor expansion. Good fitting was achieved when the conditions of low and moderate intensity were put in one model; high-intensity in another. Standard deviation of fitting error in the former condition is 0.52; in the latter is 1.82 mmol/liter. Weighting analysis demonstrated that, besides heart rate, respiratory variables are required in the estimation of [Lac]blood in the model of low/moderate intensity. In conclusion, by measuring noninvasive cardio-respiratory parameters, [Lac]blood during CWR exercise can be determined with good accuracy. This should have application in endurance training and future exercise industry

    Nano-optical observation of cascade switching in a parallel superconducting nanowire single photon detector

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    The device physics of parallel-wire superconducting nanowire single photon detectors is based on a cascade process. Using nano-optical techniques and a parallel wire device with spatially-separate pixels we explicitly demonstrate the single- and multi-photon triggering regimes. We develop a model for describing efficiency of a detector operating in the arm-trigger regime. We investigate the timing response of the detector when illuminating a single pixel and two pixels. We see a change in the active area of the detector between the two regimes and find the two-pixel trigger regime to have a faster timing response than the one-pixel regime.Comment: 11 pages, 2 figure

    Airflow dynamics and exhaled-breath temperature following cold-water ingestion

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    Introduction. Drinking cold water evokes decreases in spirometric indices of lung function. We studied whether this could be explained by changes in exhaled-breath temperature (EBT), airflow dynamics,and spirometer measurement sensitivity. Methods. In a randomized/crossover design, 10 healthy adults consumed 1,000 mL refrigerated water (2.1±0.64 ºC) or water at room temperature (19.4±0.5 ºC), with EBT assessed at baseline and at 5,10,15 and 30-min post-ingestion. The influence of EBT on pneumotachograph measurement characteristics was modelled using computational fluid dynamics (CFD). Results. At 5-min post-ingestion, EBT was lower (p<0.001) following the ingestion of cold water versus water at room-temperature (31.7±1.1 vs. 33.0±0.9 °C), and remained lower until 30-min post-ingestion. At a flow of 8 L*s−1 , a decrease in EBT of 2.1 ° 29 C (observed following cold-water ingestion) was modelled to underpredict lung volume by 0.7%. Conclusions. Cold water reduces EBT below baseline but effects pneumotachograph measurements only negligibly; thus, decreased lung function following cold-water ingestion likely has a physiological explanation which warrants further stud

    Testosterone and resistance training effects on muscle nitric oxide synthase isoforms in COPD men

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    SummaryBackgroundSkeletal muscle dysfunction contributes to exercise limitation in COPD. The role of the nitric oxide synthase (NOS) system in muscle dysfunction is ill defined. Reduced levels of endothelial NOS (eNOS) and elevated levels of inducible NOS (iNOS) in the skeletal muscle of COPD patients have been recently reported. We hypothesized that resistance exercise training (R) and/or testosterone supplementation (T) would alter the transcription and expression of the NOS isoenzymes in COPD skeletal muscle.MethodsVastus lateralis biopsies were obtained before and after a 10-week intervention in 40 men with severe COPD(age 67.7 ± 8.3, FEV1 41.4 ± 12.6% predicted): placebo + no training (P) (n = 11), placebo + resistance training (PR) (n = 8), testosterone + no training (T) (n = 11) and testosterone + resistance training (TR) (n = 10) groups. eNOS, nNOS and iNOS mRNA and protein levels were measured in each sample. mRNA and protein levels were measured using real-time PCR and enzyme-linked immunosorbant assay, respectively.ResultseNOS mRNA increased in the TR group compared to P and T groups (P < 0.001). eNOS protein was increased in TR and T groups after intervention (P < 0.05) but not in the PR group. nNOS protein increased in the PR, T, and TR groups (P < 0.05). iNOS protein decreased only in the TR group (P = 0.01).ConclusionResistance training and testosterone supplementation increased eNOS and nNOS proteins and decreased iNOS protein in the skeletal muscles of men with COPD. These changes in NO system might explain some of the favorable effects of these therapies
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