American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Apr 2000
Review Practice Guideline GuidelineDiagnostic Standards and Classification of Tuberculosis in Adults and Children. This official statement of the American Thoracic Society and the Centers for Disease Control and Prevention was adopted by the ATS Board of Directors, July 1999. This statement was endorsed by the Council of the Infectious Disease Society of America, September 1999.
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Am. J. Respir. Crit. Care Med. · Apr 2000
Physiologic determinants of ventilator dependence in long-term mechanically ventilated patients.
To investigate the pathophysiologic mechanisms of ventilator dependence, we took physiologic measurements in 28 patients with COPD and 11 postcardiac surgery (PCS) patients receiving long-term mechanical ventilation during a spontaneous breathing trial, and in 20 stable, spontaneously breathing patients matched for age and disease. After 40 +/- 14 min of spontaneous breathing, 20 of 28 patients with COPD and all 11 PCS patients were judged ventilator-dependent (VD). We found that in the 31 VD patients tidal volume was low (VT: 0.36 +/- 0.12 and 0.31 +/- 0.08 L for COPD and PCS, respectively), neuromuscular drive was high (P(0.1): 5.6 +/- 1. 6 and 3.9 +/- 1.9 cm H(2)O), inspiratory muscle strength was reduced (Pdi(max): 42 +/- 12 and 28 +/- 15 cm H(2)O), and lung mechanics were abnormal, particularly PEEPi (5.9 +/- 3.0 cm H(2)O) and lung resistance (22.2 +/- 9.2 cm H(2)O/L/s) in COPD. ⋯ In the 31 VD patients, Pa(CO(2)) increased during the weaning trial (+12.3 +/- 8.0 mm Hg). We conclude that in the presence of a high drive to breathe, the imbalance between increased work load and reduced inspiratory muscle strength causes respiratory distress and CO(2) retention. Noninvasive measurements (breathing pattern, P(0.1), P(0.1)/ VT/TI) may give better insight into weaning failure useful in clinical decision-making, particularly in patients with COPD not showing rapid shallow breathing (56% in this study).
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Am. J. Respir. Crit. Care Med. · Apr 2000
Randomized Controlled Trial Multicenter Study Clinical TrialLong-acting bronchodilation with once-daily dosing of tiotropium (Spiriva) in stable chronic obstructive pulmonary disease.
Tiotropium (Spiriva; Ba679BR) is a new-generation, long-acting anticholinergic bronchodilator that has muscarinic M(1) and M(3) receptor subtype selectivity. A multicenter, randomized, double-blind, parallel group, placebo-controlled study was conducted to evaluate the dose-response characteristics of tiotropium inhalation powder given once daily to stable patients with chronic obstructive pulmonary disease (COPD). Patients (mean FEV(1) = 1.08 L [42% predicted]) were randomized to receive 0, 4.5, 9, 18, or 36 microg tiotropium once daily at noon for 4 wk, with spirometry done before and hourly for 6 h after dosing. ⋯ In summary, tiotropium was shown to be safe and effective in doses ranging from 4.5 to 36 microg delivered once daily. The improvements in spirometry with once-daily dosing confirm the long duration of action of tiotropium reported in single-dose studies, and its sustained improvement of spirometric measures over the 1 mo of testing in the study points to utility of tiotropium as a maintenance bronchodilator for patients with COPD. On the basis of the comparable bronchodilator response at doses from 9 to 36 microg, and advantages suggested by the safety profile at doses below 36 microg in this study, a dose of 18 microg once daily was selected for use in long-term studies of the safety and efficacy of tiotropium.
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Am. J. Respir. Crit. Care Med. · Apr 2000
Inhibitory effects of a lecithinized superoxide dismutase on bleomycin-induced pulmonary fibrosis in mice.
Oxidant/antioxidant imbalance is thought to be involved in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Therefore, antioxidants, such as superoxide dismutase (SOD), are expected to have an inhibitory potential against IPF. To elucidate whether a lecithinized SOD (phosphatidylcholine [PC]-SOD) has the potential to be a new therapeutic agent for IPF, we investigated the inhibitory effects of PC-SOD at doses of 1 mg/kg/d (low dose) and 10 mg/kg/d (high dose) and of methylprednisolone (mPSL) on bleomycin (BLM)-induced pulmonary fibrosis in mice. ⋯ In bronchoalveolar lavage fluid on Day 1 after treatment with BLM, BLM-induced increases in total cell number, populations of lymphocytes and neutrophils, and expression of messenger RNA for interleukin-1beta and platelet-derived growth factor (PDGF)-A were significantly suppressed in PC-SOD-treated mice. The suppression of PDGF-A expression was significantly greater in mice treated with low-dose PC-SOD than in mice treated with high-dose PC-SOD or mPSL. In summary, this study demonstrated the inhibitory effects of low-dose PC-SOD on the development of pulmonary fibrosis, which indicates the potential usefulness of PC-SOD as a new treatment agent for IPF or at least for BLM-induced pulmonary fibrosis in humans.