The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
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Hypoxia and exertion are considered as the two main factors in the development of high-altitude pulmonary oedema (HAPE), however its pathophysiology remains unclear. Therefore, we established a model in which 32 Sprague-Dawley rats were randomly assigned to normoxic rest, hypoxic rest, normoxic exercise and hypoxic exercise. An altitude of 4,700 m was simulated using hypobaric hypoxia, while exercise consisted 48 h walk with 15-20 min breaks every 4 h. ⋯ In the same group, lung histology showed typical haemorrhagic lung oedema and disruption of both alveolar epithelium and capillary endothelium while hypoxia or exertion alone only induced slight endothelium and epithelium swelling/disruption. Our study established a direct link between histological and physiological evidence of HAPE-like symptoms and we demonstrated that hypoxia and exertion can synergistically induce HAPE-like symptoms in Sprague-Dawley rats without inducing lung inflammation. We therefore propose that alveolar epithelium and capillary endothelium stress failure play a major role in the development of HAPE.
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Randomized Controlled Trial Multicenter Study
Shift in sleep apnoea type in heart failure patients in the CANPAP trial.
In patients with heart failure (HF), the predominant type of sleep apnoea can change over time in association with alterations in circulation time. The aim of this study was to determine whether, in some patients with HF, a spontaneous shift from mainly central (>50% central events) to mainly obstructive (>50% obstructive events) sleep apnoea (CSA and OSA, respectively) over time coincides with improvement in left ventricular ejection fraction (LVEF). Therefore, sleep studies and LVEFs of HF patients with CSA from the control arm of the Canadian Continuous Positive Airway Pressure for Patients with Central Sleep Apnea and Heart Failure (CANPAP) trial were examined to determine whether some converted to mainly OSA and, if so, whether this was associated with an increase in LVEF. ⋯ Compared with those in the nonconversion group, those in the conversion group had a significantly greater increase in the LVEF (2.8% versus -0.07%) and a significantly greater fall in the lung-to-ear circulation time (-7.6 s versus 0.6 s). In patients with HF, spontaneous conversion from predominantly CSA to OSA is associated with an improvement in left ventricular systolic function. Future studies will be necessary to further examine this relationship.
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Randomized Controlled Trial
SCH527123, a novel CXCR2 antagonist, inhibits ozone-induced neutrophilia in healthy subjects.
SCH527123 is a novel, selective CXC chemokine receptor 2 antagonist that inhibits neutrophil activation and modulates neutrophil trafficking in animal models, characteristics that may be beneficial in the treatment of conditions with unbalanced pulmonary neutrophilia, such as chronic obstructive pulmonary disease. The purpose of this proof-of-principle study was to determine whether SCH527123 inhibits ozone-induced neutrophil recruitment in healthy humans. In a randomised, double-blind, placebo-controlled, three-way crossover study, oral SCH527123 (50 mg once daily, 4 days), prednisolone (50 mg once), or placebo was alternated with 2-week washouts. 18 healthy ozone responders (>20% increase in sputum neutrophils) underwent ozone challenge tests (250 ppb, 3 h intermittent exercise) 1 h after the last treatment dose. ⋯ All treatments were safe and well tolerated. SCH527123 causes significant attenuation of ozone-induced airway neutrophilia in healthy subjects. Further evaluation in a large trial of patients with pulmonary disorders is warranted.
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Randomized Controlled Trial Multicenter Study
Is treatment with ICS and LABA cost-effective for COPD? Multinational economic analysis of the TORCH study.
The TOwards a Revolution in COPD Health (TORCH) study was a 3-yr multicentre trial of 6,112 patients randomised to salmeterol (Salm), fluticasone propionate (FP), a Salm/FP combination (SFC) or placebo (P). Here the cost-effectiveness of treatments evaluated in the TORCH study is assessed. For four regions, 3-yr all-cause hospitalisation, medication and outpatient care costs were calculated. ⋯ Estimates for Salm versus P (197,000 USD) and FP versus P (78,000 USD) were less favourable. The US estimates were greater than those from other regions; for SFC versus P, the cost per QALY was 77,100 (46,200-241,700) USD compared to 24,200 (15,200-56,100) USD in Western Europe. Compared with P, SFC has a lower incremental cost-effectiveness ratio than either FP or Salm used alone, and is, therefore, preferred to these monotherapies on the grounds of cost-effectiveness.
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Most pressure-support devices use a single circuit with an exhalation port integrated in the mask. The aim of the current study was to compare the effects of masks having different manufacturer-inserted leaks on ventilator performance. We simulated chronic obstructive pulmonary disease and restrictive disease. ⋯ The mask with the smallest leak-increased inspiratory-trigger delay was Synchrony 2 in the simulated obstructive-disease condition and increased rebreathing. The in vivo study confirmed the bench results. When switching to a mask that has a different leak, evaluation is needed to adjust trigger sensitivity and pressurisation level and to check the absence of rebreathing.