Document Detail

Mechanical parameters determining pharyngeal collapsibility in patients with sleep apnea.
MedLine Citation:
PMID:  20576847     Owner:  NLM     Status:  MEDLINE    
The relative impact of mechanical factors on pharyngeal patency in patients with obstructive sleep apnea is poorly understood. The present study was designed to evaluate parameters of the "tube law" on pharyngeal pressure-flow relationships and collapsibility in patients with obstructive sleep apnea. We developed a mathematical model that considered the collapsible segment of the pharynx to represent an orifice of varying diameter. The model enabled us to assess the effects of pharyngeal compliance (C), neutral cross-sectional area (A(o)), external peripharyngeal pressure (P(ex)), and the resistance proximal to the site of collapse on flow mechanics and pharyngeal collapsibility [critical pressure (P(crit))]. All parameters were measured in 15 patients with obstructive sleep apnea under propofol anesthesia, both at rest and during mandibular advancement and electrical stimulation of the genioglossus. The data was used both to confirm the validity of the model and to compare expected and actual relationships between the tube-law parameters and the pharyngeal pressure-flow relationship and collapsibility. We found a close correlation between predicted and measured P(crit) (R = 0.98), including changes observed during pharyngeal manipulations. C and A(o) were closely and directly interrelated (R = 0.93) and did not correlate with P(crit). A significant correlation was found between P(ex) and P(crit) (R = 0.77; P < 0.01). We conclude that the pharynx of patients with obstructive sleep apnea can be modeled as an orifice with varying diameter. Pharyngeal compliance and A(o) are closely interrelated. Pharyngeal collapsibility depends primarily on the surrounding pressure.
Arie Oliven; Eran Kaufman; Rotem Kaynan; Ron Oliven; Uri Steinfeld; Nave Tov; Majed Odeh; Luis Gaitini; Alan R Schwartz; Eitan Kimmel
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2010-06-24
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  109     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-10-13     Completed Date:  2011-05-23     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1037-44     Citation Subset:  IM    
Department of Medicine, Bnai-Zion Medical Center, Technion, Haifa, Israel.
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MeSH Terms
Anesthesia, General
Continuous Positive Airway Pressure
Electric Stimulation
Mandibular Advancement
Middle Aged
Models, Biological
Pharynx / innervation,  pathology,  physiopathology*
Reproducibility of Results
Respiratory Mechanics
Sleep Apnea Syndromes / pathology,  physiopathology*

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

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