1,720,973 research outputs found
Different modes of noninvasive intermittent positive pressure ventilation (IPPV) in acute exacerbations of COLD patients.
No full textPatients with chronic obstructive lung disease may suffer from acute exacerbations of their disease, which may lead to acute respiratory failure necessitating endotracheal intubation and mechanical ventilation. We have compared retrospectively the results obtained with nasal positive pressure ventilation and those of standard medical therapy in acute relapses of severe COLD. The study showed that nasal IPPV (NIPPV) in control mode delivered for approximately 1 h, four times daily, six days a week over a 21 day period, does not result in independent improvement of acute exacerbation of COLD. In the next study the data seem to indicate, in apparent contrast, a marked reduction in the need for endotracheal intubation using noninvasive ventilation, both with assist-control and pressure support noninvasive modes, in comparison with an historical control group. We did not find a significant difference in the success rate of the two modes, but compliance to noninvasive ventilation was better with pressure support. In the former study patients showing neurological signs and requiring mechanical ventilation were excluded, while in the last study patients were selected on the basis of necessity of mechanical ventilation. The fact that in the last study, ventilation was applied by face mask instead of nasal mask may have influenced results. Further efforts are required to determine whether non-invasive ventilation is more a preventive measure to avoid endotracheal intubation, or is another means of delivering ventilatory support
Methacholine inhaled challenge: study of correlation among different indices expressing the result.
No full textWe tested measures of specific airway conductance (sGaw) and forced expiratory volume in one second (FEV1) versus transcutaneous oxygen tension (Ptc,O2) during inhaled methacholine bronchial challenge in 60 out-patients (38 males 22 females, mean age 33 +/- 13 yrs). The provocative doses of methacholine needed to produce a 35\% decrease of sGaw (PD35,sGaw), a 20\% fall in FEV1 (PD20,FEV1) and a 20\% decrease in Ptc,O2 (PD20,O2) were simultaneously derived from the dose-response curves. Two groups were identified according to the PD20,FEV1 result ("responders" with a PD20,FEV1 2,000 micrograms methacholine). All three indices derived from the dose-response curves differed significantly between the groups (p < 0.00005). The relationship analysis showed a significantly better value for PD20,O2 versus PD35,sGaw (r = 0.98) than versus PD20, FEV1 (r = 0.62). We observed similar baseline levels and variations in arterial oxygen tension (Pa,O2) and Ptc,O2 during methacholine challenge (-25 and -27\%, respectively) in 14 randomly studied responders. Thus, inhaled methacholine-induced hypoxaemia (PD20,O2) seems to reflect PD35,sGaw better than changes in FEV1. Our investigation supports the hypothesis that PD20,O2 could be useful in interpreting the methacholine inhaled challenge. It could be of help in clarifying the pathophysiological meaning of the concurrent hypoxaemia during this challenge, which should be further elucidated
Acute exacerbations in patients with COPD: predictors of need for mechanical ventilation.
No full textPredictive factors in mechanically-ventilated patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) have been extensively studied but not in spontaneously breathing patients. The aim of this retrospective study was to evaluate the contribution of parameters of respiratory mechanics, clinical and nutritional status in predicting the need for mechanical ventilation (MV) in COPD patients treated with medical therapy for an acute exacerbation. Anthropometric data, Acute Physiology and Chronic Health Evaluation (APACHE) II score, bedside spirometry, breathing pattern, respiratory mechanics and blood gases were measured in 39 COPD patients upon hospital admission for exacerbation of their disease. Fourteen patients in whom MV was necessary were compared with 25 patients in whom medical therapy was enough for a good outcome. The discriminant analysis showed, with decreasing order of power, that nutritional prognostic index (NPI), APACHE II score, forced expiratory volume in one second/forced vital capacity (FEV1/FVC) ratio, vital capacity (VC) (\% predicted) and FVC (\% pred) provided a significant distinction between the two groups. The discriminant equation considering NPI, and FVC (\% pred) could correctly predict the success in 76\% of the patients. A multiparametric stepwise regression analysis showed that APACHE II score was significantly correlated with NPI, VC (\% pred), pressure time index (PTI) and duty cycle, i.e. fraction of inspiration to duration of total breathing cycle (tl/ttot). In conclusion, underlying general conditions as assessed by malnutrition and APACHE II score were shown to be unfavourable indices of outcome for chronic obstructive pulmonary disease patients who experienced an exacerbation of their disease and were treated with medical therapy. Flow limitation data as assessed by the forced expiratory manoeuvre may provide additional information
Transcutaneous partial oxygen tension and lung mechanics during methacholine inhaled challenge.
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Long-term home care programmes may reduce hospital admissions in COPD with chronic hypercapnia.
No full textLong-term oxygen therapy (LTOT) has been shown to improve survival in chronic obstructive pulmonary disease (COPD) patients. The clinical effectiveness of long-term home mechanical ventilation (HMV) is still discussed, nevertheless both LTOT and HMV are often included in the home care programmes of these patients. To evaluate the effectiveness of home care programmes including either HMV or LTOT, 34 COPD patients were studied. They were admitted to either HMV (Group A: 12 males and 5 females, aged 62 +/- 5 yrs), or LTOT (Group B: 9 males and 8 females, aged 62 +/- 8 yrs). They were compared to a historical group (Group C: 19 males and 10 females, aged 67 +/- 16 yrs) performing only their usual standard LTOT during the same period. Spirometry, maximal inspiratory pressure and arterial blood gas values were assessed at baseline and at 6, 12 and 18 months of follow-up. Mortality rate and number of hospital and intensive care unit (ICU) admissions and days of hospitalization were also assessed. Four out of 17 (23\%) patients in Group A, 3 out of 17 (18\%) in Group B, and 5 out of 29 (17\%) in Group C died within 18 months. Of the lung function tests, only maximal inspiratory pressure in Group A showed a significant increase in the 18th month (50 +/- 4 to 56 +/- 7 cmH2O; p<0.01). In comparison to 18 months prior to the study, hospital admissions (from 2.2 +/- 0.6 to 1.3 +/- 1.1 and from 2.0 +/- 0.7 to 1.0 +/- 0.9 for Group A and B, respectively; p<0.005 for both), and days of hospitalization (from 60 +/- 34 to 34 +/- 40 and from 55 +/- 23 to 18 +/- 20 days in Group A and B, respectively; p<0.005 for both) significantly decreased only in the two groups submitted to the home care programme. We conclude that home care programmes may be effective in the long-term treatment of chronically hypercapnic chronic obstructive pulmonary disease patients in reducing hospital admissions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Exhaled nitric oxide and exercise tolerance in severe COPD patients.
No full textStudy objective: To evaluate exhaled nitric oxide (eNO) during exercise in stable COPD patients.Setting: Outpatients' evaluation in a rehabilitation center.Patients: Eleven consecutive stable male COPD patients (age 65±6 years, FEV1 56±10% pred). Eight healthy (6 male; age: 51±16 years) non-smoking, non-atopic volunteers served as controls.Methods: In each subject a symptom-limited cycloergometry was carried out by monitoring eNO with the tidal-breath method to assess eNO concentration (FENO) and output ( NO ) at rest, peak exercise and recovery time.Results: Resting FENO (9.8±5.1 and 14.1±6.3 ppb respectively) and NO (4.2±2.0 and 5.9±3.4 nM*min-1 respectively) were lower though non significantly in COPD than in controls. In both groups FENO significantly decreased whereas NO significantly increased during exercise. Both parameters returned to baseline during the recovery time. Peak exercise NO but not FENO was significantly lower in COPD than in controls (7.9±5.4 and 12.7±6.0 nM*min-1 respectively, p<0.05). The rise in VNO was weakly correlated to O2 both in controls (R=0.31, p=0.002) and in COPD patients (R=0.22, p=0.03). FENO showed an inverse correlation to O2 in both groups (R= -0.53, p=0.000; R= -0.31, p=0.003 in controls and COPD respectively). Conclusions: In mild and moderate COPD patients eNO during exercise parallels that observed in normal controls. Exhaled NO output but not concentration is significantly reduced at peak exercise in COPD as compared to controls. The long-term effects of exercise training on eNo has to be evaluated by further studies
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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