Document Detail

Inspiratory dynamic obstruction detected by forced oscillation during CPAP. A model study.
MedLine Citation:
PMID:  9117031     Owner:  NLM     Status:  MEDLINE    
Assessment of upper airway mechanics in patients with obstructive sleep apnea/hypopnea (OSA) can be carried out qualitatively from indirect signals (flow pattern, snoring, strain gauges, inductance plethysmography) or quantitatively by means of invasive estimation of esophageal pressure. The forced oscillation technique (FOT) is a noninvasive method of potential interest for quantitatively assessing airway obstruction in the sleeping patient. The aim of this work was to ascertain in a model study whether FOT could provide an index of airway obstruction when applied at the conditions of total and partial occlusions similar to the ones found in patients with OSA. An airway analog closely mimicking upper airway collapsibility was constructed and mechanically characterized by the relationship between its flow, upstream and downstream pressures as well as by means of FOT. We simulated total collapse (apnea), different levels of partial collapse with flow limitation (hypopnea), and release of airway obstruction when the collapsible analog was used as an artificial upper airway in a spontaneously breathing subject submitted to continuous positive airway pressure (CPAP) up to 14 cm H2O.s/L. The results showed that the amplitude of airway impedance measured by FOT was a suitable index to detect obstruction in collapsible segments. We concluded from this realistic model study that FOT could be a valuable tool for quantitatively assessing airway obstruction in patients with OSA treated with CPAP. This noninvasive technique is potentially useful both in studying upper airway mechanics in detail and in automatically monitoring airway obstruction in routine studies.
R Farré; R Peslin; M Rotger; D Navajas
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of respiratory and critical care medicine     Volume:  155     ISSN:  1073-449X     ISO Abbreviation:  Am. J. Respir. Crit. Care Med.     Publication Date:  1997 Mar 
Date Detail:
Created Date:  1997-04-18     Completed Date:  1997-04-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9421642     Medline TA:  Am J Respir Crit Care Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  952-6     Citation Subset:  AIM; IM    
Laboratori Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, Spain.
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MeSH Terms
Airway Obstruction / diagnosis*,  etiology
Equipment Design
Models, Biological
Positive-Pressure Respiration*
Respiratory Mechanics*
Sleep Apnea Syndromes / complications,  physiopathology*

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