Document Detail

Noninvasive determination of upper airway resistance and flow limitation.
MedLine Citation:
PMID:  15169753     Owner:  NLM     Status:  MEDLINE    
We have shown that a polynomial equation, FP = AP3 + BP2 + CP + D, where F is flow and P is pressure, can accurately determine the presence of inspiratory flow limitation (IFL). This equation requires the invasive measurement of supraglottic pressure. We hypothesized that a modification of the equation that substitutes time for pressure would be accurate for the detection of IFL and allow for the noninvasive measurement of upper airway resistance. The modified equation is Ft = At3 + Bt2 + Ct + D, where F is flow and t is time from the onset of inspiration. To test our hypotheses, data analysis was performed as follows on 440 randomly chosen breaths from 18 subjects. First, we performed linear regression and determined that there is a linear relationship between pressure and time in the upper airway (R2 0.96 +/- 0.05, slope 0.96 +/- 0.06), indicating that time can be a surrogate for pressure. Second, we performed curve fitting and found that polynomial equation accurately predicts the relationship between flow and time in the upper airway (R2 0.93 +/- 0.12, error fit 0.02 +/- 0.08). Third, we performed a sensitivity-specificity analysis comparing the mathematical determination of IFL to manual determination using a pressure-flow loop. Mathematical determination had both high sensitivity (96%) and specificity (99%). Fourth, we calculated the upper airway resistance using the polynomial equation and compared the measurement to the manually determined upper airway resistance (also from a pressure-flow loop) using Bland-Altman analysis. Mean difference between calculated and measured upper airway resistance was 0.0 cmH2O x l(-1) x s(-1) (95% confidence interval -0.2, 0.2) with upper and lower limits of agreement of 2.8 cmH2O x l(-1) x s(-1) and -2.8 cmH2O x l(-1) x s(-1). We conclude that a polynomial equation can be used to model the flow-time relationship, allowing for the objective and accurate determination of upper airway resistance and the presence of IFL.
Khaled F Mansour; James A Rowley; M Safwan Badr
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Publication Detail:
Type:  Journal Article     Date:  2004-05-28
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  97     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2004 Nov 
Date Detail:
Created Date:  2004-10-11     Completed Date:  2005-02-25     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:  1840-8     Citation Subset:  IM    
Sleep Research Laboratory, John D. Dingell Veterans Affairs Medical Center, Division of Pulmonary, Critical Care and Sleep Medicine, Wayne State University, Detroit, Michigan 48201, USA.
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MeSH Terms
Airway Resistance*
Feasibility Studies
Models, Biological*
Sleep Apnea Syndromes / diagnosis*

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

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