Document Detail

The appropriate setting of noninvasive pressure support ventilation in stable COPD patients.
MedLine Citation:
PMID:  11083676     Owner:  NLM     Status:  MEDLINE    
STUDY OBJECTIVE: To evaluate the short-term physiologic effects of two settings of nasal pressure-support ventilation (NPSV) in stable COPD patients with chronic hypercapnia. DESIGN: Randomized controlled physiologic study. SETTING: Lung function units and outpatient clinic of two affiliated pulmonary rehabilitation centers. PATIENTS: Twenty-three patients receiving domiciliary nocturnal NPSV for a mean (+/- SD) duration of 31 +/- 20 months. METHODS: Evaluation of arterial blood gases, breathing pattern, respiratory muscles, and dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn) during both unassisted and assisted ventilation. Two settings of NPSV were randomly applied for 30 min each: (1) usual setting (U), the setting of NPSV actually used by the individual patient at home; and (2) physiologic setting (PHY), the level of inspiratory pressure support (IPS) and external positive end-expiratory pressure (PEEPe) tailored to patient according to invasive evaluation of respiratory muscular function and mechanics. RESULTS: All patients tolerated NPSV well throughout the procedure. Mean U was IPS, 16 +/- 3 cm H(2)O and PEEPe, 3.6 +/- 1.4 cm H(2)O; mean PHY was IPS, 15 +/- 3 cm H(2)O and PEEPe, 3.1 +/- 1.6 cm H(2)O. NPSV was able to significantly (p < 0.01) improve arterial blood gases independent of the setting applied. When compared with spontaneous breathing, both settings induced a significant increase in minute ventilation (p < 0.01). Both settings were able to reduce the diaphragmatic pressure-time product, but the reduction was significantly greater with PHY (by 64%; p < 0.01) than with U (56%; p < 0.05). Eleven of 23 patients (48%) with U and 7 of 23 patients (30%) with PHY showed ineffective efforts (IE); the prevalence of IE (20 +/- 39% vs 6 +/- 11% of their respiratory rate with U and PHY, respectively) was statistically different (p < 0.05). CONCLUSION: In COPD patients with chronic hypercapnia, NPSV is effective in improving arterial blood gases and in unloading inspiratory muscles independent of whether it is set on the basis of patient comfort and improvement in arterial blood gases or tailored to a patient's respiratory muscle effort and mechanics. However, setting of inspiratory assistance and PEEPe by the invasive evaluation of lung mechanics and respiratory muscle function may result in reduction in ineffective inspiratory efforts. These short-term results must be confirmed in the long-term clinical setting.
M Vitacca; S Nava; M Confalonieri; L Bianchi; R Porta; E Clini; N Ambrosino
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  Chest     Volume:  118     ISSN:  0012-3692     ISO Abbreviation:  Chest     Publication Date:  2000 Nov 
Date Detail:
Created Date:  2000-11-29     Completed Date:  2000-12-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0231335     Medline TA:  Chest     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1286-93     Citation Subset:  AIM; IM    
Pulmonary Department, Scientific Institute of Gussago, Fondazione Salvatore Maugeri IRCCS, Gussago, Italy.
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MeSH Terms
Carbon Dioxide / blood
Chronic Disease
Diaphragm / physiopathology
Follow-Up Studies
Home Care Services
Hypercapnia / physiopathology,  therapy
Inhalation / physiology
Lung / physiopathology
Lung Diseases, Obstructive / physiopathology,  therapy*
Maximal Voluntary Ventilation / physiology
Oxygen / blood
Positive-Pressure Respiration / methods*
Positive-Pressure Respiration, Intrinsic / physiopathology
Respiratory Mechanics / physiology
Respiratory Muscles / physiopathology
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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