Document Detail

Relationship between critical pressure and volume exhaled during negative pressure in awake subjects with sleep-disordered breathing.
MedLine Citation:
PMID:  20139226     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Critical pressure (Pcrit) is considered a reliable parameter to evaluate the mechanical properties of the passive upper airway (UA) and is significantly increased in patients with obstructive sleep apnea-hypopnea (OSAH) compared with normal subjects. The volume exhaled in the first 0.5 s after application at the mouth of 5 cm H(2)O negative pressure at the onset of expiration (V,NEP(0.5)) during wakefulness has been used as a marker of UA collapsibility. The aim of this study was to investigate if there is a significant relationship between V,NEP(0.5) and Pcrit in normal subjects, snorers, and patients with OSAH. METHODS: Thirty men, 10 with OSAH (aged 64 +/- 9.1 years, BMI 32 +/- 4.9 kg/m(2), apnea-hypopnea index [AHI] 43.8 +/- 24, neck circumference 46.6 +/- 3.7 cm), 10 snorers (aged 68 +/- 11 years, BMI 26.6 +/- 4.6 kg/m(2), AHI 3.5 +/- 0.8, snoring time > or = 30% of sleep time, neck circumference 42.2 +/- 3.9 cm), and 10 controls (aged 67 +/- 12 years, BMI 25.4 +/- 2.2 kg/m(2), AHI 1.9 +/- 1.2, neck circumference 41.2 +/- 2.2 cm) underwent V,NEP(0.5) measurement in supine position while awake and Pcrit measurement during sleep. Correlation between V,NEP(0.5) and Pcrit was performed in all subjects. RESULTS: Controls had V,NEP(0.5) of 456 +/- 82 mL and Pcrit of -1.38 +/- 0.6 cm H(2)O, snorers had V,NEP(0.5) of 321 +/- 33 mL and Pcrit -0.55 +/- 0.3 cm H(2)O, and patients with OSAH showed V,NEP(0.5) of 295 +/- 67 mL and Pcrit of 0.99 +/- 1 cm H(2)O (P < .001 vs normal subjects). A strong correlation was found between V,NEP(0.5) and Pcrit (r(2) = 0.61, P < .0001). CONCLUSIONS: In males with neck circumference > 37 cm, V,NEP(0.5) during wakefulness strongly reflects Pcrit in a wide range of values. Our findings suggest that V,NEP(0.5) can be used as valuable substitute for Pcrit to assess UA collapsibility for clinical and research purposes in these subjects.
Luigi Taranto Montemurro; Michela Bettinzoli; Luciano Corda; Alessia Braghini; Claudio Tantucci
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Publication Detail:
Type:  Journal Article     Date:  2010-02-05
Journal Detail:
Title:  Chest     Volume:  137     ISSN:  1931-3543     ISO Abbreviation:  Chest     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-06-07     Completed Date:  2010-07-15     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0231335     Medline TA:  Chest     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1304-9     Citation Subset:  AIM; IM    
Cattedra di Malattie dell'Apparato Respiratorio, Spedali Civili, Brescia, Italy.
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MeSH Terms
Airway Obstruction / physiopathology
Analysis of Variance
Body Mass Index
Exhalation / physiology*
Linear Models
Middle Aged
Neck / anatomy & histology
Pharynx / physiopathology*
Respiratory Function Tests
Risk Factors
Sleep Apnea Syndromes / physiopathology*
Snoring / physiopathology

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

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