Abstract:
:To investigate the mechanisms underlying ventilator-dependence in patients with chronic obstructive pulmonary disease (COPD), and to assess the effects of the combination of positive end-expiratory pressure (PEEP) and pressure-support ventilation (PSV) on inspiratory muscle effort, we investigated respiratory mechanics in eight ventilator-dependent COPD patients. The patients' breathing pattern, lung mechanics, diaphragmatic effort (PTPdi), diaphragmatic tension-time index (TTdi), and arterial blood gases were measured during both spontaneous breathing (SB) and ventilatory assistance consisting of PSV alone (15, 20, and 25 cm H2O) and PSV combined with a PEEP of 5 cm H2O (reducing PSV to 10, 15, and 20 cm H2O, respectively, to maintain equivalent inspiratory pressure). The different levels of ventilatory support were delivered in a randomized sequence. Maximal inspiratory (MIP), esophageal (PpImax) and transdiaphragmatic (Pdi(max)) pressures and respiratory drive (P(0.1)) were measured at the beginning of the procedure during SB. We found a high P(0.1) (6.1 +/- 1.7 cm H2O), which seemed to rule out an impairment of respiratory-center output. Apparently, inspiratory muscle strength was compatible with successful weaning (38.5 +/- 8.8, 50.9 +/- 9.7, and 51.8 +/- 9.5 cm H2O for MIP, PPImax and Pdi(max), respectively). However, abnormal respiratory mechanics (particularly an intrinsic positive end-expiratory pressure (PEEPi) of 8.3 +/- 1.9 cm H2O and pulmonary resistance 24.7 +/- 9.5 cm H2O/L/s imposed an excessive load on the inspiratory muscles, as indicated by a high PTPdi (499 +/- 122 cm H2O x s). Increasing levels of PSV progressively and significantly unloaded the patients' inspiratory muscles, although at pressures above 20 cm H2O uncoupling occurred between patient and ventilator respiratory frequency. Application of PEEP during PSV improved ventilatory assistance by further reducing the inspiratory effort (by 17% on average) and by ameliorating patient-ventilator interaction. We conclude that the excessive mechanical load, and in particular the high PEEPi, is the major determinant of ventilator-dependence in COPD patients. Application of PEEP improves the efficiency of PSV in unloading these patients' inspiratory muscles, and can sometimes improve patient-ventilator interaction.
journal_name
Am J Respir Crit Care Medauthors
Appendini L,Purro A,Patessio A,Zanaboni S,Carone M,Spada E,Donner CF,Rossi Adoi
10.1164/ajrccm.154.5.8912740subject
Has Abstractpub_date
1996-11-01 00:00:00pages
1301-9issue
5eissn
1073-449Xissn
1535-4970journal_volume
154pub_type
临床试验,杂志文章,随机对照试验abstract::This study aimed to examine the performance characteristics of four high-frequency oscillatory-type ventilators, using an in vitro model of the intubated neonatal respiratory system. Each ventilator was examined across its operative range of settings and at varying model lung compliance (C) and resistance. The oscilla...
journal_title:American journal of respiratory and critical care medicine
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abstract::While signal transducer and activator of transcription protein 6 (STAT6) is important in interleukin-4 (IL-4)-induced commitment of CD4(+) T cells to the T helper cell, type 2 (Th2) phenotype and IgE isotype switching in B cells, its role in other IL-4-mediated events and their impact upon the allergic response is les...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
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abstract::Aeroallergens such as Amb a I from short ragweed are important in the development of allergic airway disease. We tested the ability of a human monoclonal immunoglobulin-A (IgA) antibody specific for Amb a I (A-IgA) to modulate airway responsiveness and lung eosinophilia after airway challenge with nebulized Amb a I or...
journal_title:American journal of respiratory and critical care medicine
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doi:10.1164/ajrccm.158.2.9801014
更新日期:1998-08-01 00:00:00
abstract:RATIONALE:Tissue resident memory T cells play a critical role in the defense against inhaled pathogens. The isolation and study of human lung tissue resident memory T cells and lung resident macrophages is limited by experimental constraints. OBJECTIVES:To characterize the spatial and functional relationship between l...
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abstract:RATIONALE:Systemic steroids are the standard treatment for bronchiolitis obliterans syndrome (BOS) after allogeneic hematopoietic stem cell transplantation (HSCT) despite their poor efficacy and disabling side effects. OBJECTIVES:To evaluate the effectiveness and tolerance of budesonide/formoterol as an alternative tr...
journal_title:American journal of respiratory and critical care medicine
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abstract::There have been four types of drug treatment of asthma that have been used over the past 100 years. Belladonna alkaloids, derived from the thorn-apple plant were used in 1905, and chemically synthesized entities in this class are still in use today. Western medicine began to use adrenergic stimulants approximately 100...
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pub_type: 历史文章,杂志文章
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doi:10.1164/ajrccm.156.5.9702084
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pub_type: 杂志文章,多中心研究
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更新日期:2013-07-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,多中心研究
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更新日期:1997-01-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
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更新日期:1999-09-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
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更新日期:1994-12-01 00:00:00
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pub_type: 杂志文章
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更新日期:2011-03-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
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更新日期:2002-05-15 00:00:00
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pub_type: 杂志文章
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journal_title:American journal of respiratory and critical care medicine
pub_type: 临床试验,杂志文章,随机对照试验
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pub_type: 临床试验,杂志文章
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更新日期:2007-01-15 00:00:00
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更新日期:2001-11-15 00:00:00
abstract::The long-acting beta 2-agonist salmeterol has been suggested to have other pharmacologic activities, that is, antiinflammatory capacities, in addition to its bronchodilator properties. We investigated the protective effect of 50 micrograms salmeterol in a placebo-controlled study on house dust mite-induced early- and ...
journal_title:American journal of respiratory and critical care medicine
pub_type: 临床试验,杂志文章
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更新日期:1994-11-01 00:00:00
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更新日期:2021-01-05 00:00:00
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journal_title:American journal of respiratory and critical care medicine
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更新日期:2009-07-15 00:00:00
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更新日期:2000-03-01 00:00:00
abstract::Fibrosing alveolitis in systemic sclerosis is histologically identical to lone cryptogenic fibrosing alveolitis (CFA) (idiopathic pulmonary fibrosis). The inflammatory cell content of bronchoalveolar lavage (BAL) samples has been used as a guide to prognosis and treatment in CFA. In this study, the relationship was ex...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
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更新日期:1994-08-01 00:00:00
abstract::Glucocorticoids (GC) are the most effective anti-inflammatory drugs used in asthma. By a process called trans-activation, they increase the transcription of genes involved in either beneficial processes or certain side effects. Through trans-repression, they inhibit the transcription factors nuclear factor kappa B (NF...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
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更新日期:2000-07-01 00:00:00
abstract::Rationale: Long noncoding RNAs (lncRNAs) are emerging as important regulators of diverse biological functions. Their role in pulmonary arterial hypertension (PAH) remains to be explored.Objectives: To elucidate the role of TYKRIL (tyrosine kinase receptor-inducing lncRNA) as a regulator of p53/ PDGFRβ (platelet-derive...
journal_title:American journal of respiratory and critical care medicine
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更新日期:2020-11-15 00:00:00
abstract:RATIONALE:Inhaled corticosteroids are commonly prescribed to patients with chronic obstructive pulmonary disease (COPD). OBJECTIVES:To examine whether these medications might be associated with an excess risk of pneumonia. METHODS:We conducted a nested case-control study within a cohort of patients with COPD from Que...
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更新日期:2007-07-15 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.152.1.7599830
更新日期:1995-07-01 00:00:00