Area Under the Expiratory Flow-Volume Curve as a Tool to Assess Small Airway Disease in Global Lung Initiative Versus National Health and Nutrition Survey III Based Spirometry

2019 ◽  
Author(s):  
Octavian Ioachimescu ◽  
James K. Stoller
Keyword(s):  
National Health ◽  
Airway Disease ◽  
Small Airway ◽  
Flow Volume ◽  
Nutrition Survey ◽  
Health And Nutrition ◽  
Small Airway Disease ◽  
Volume Curve ◽  
Flow Volume Curve ◽  
Expiratory Flow

scholarly journals Assessing small airway disease in GLI versus NHANES III based spirometry using area under the expiratory flow-volume curve

2019 ◽  
Vol 6 (1) ◽  
pp. e000511 ◽  
Author(s):  
Octavian C Ioachimescu ◽  
James K Stoller
Keyword(s):  
Airway Disease ◽  
Nhanes Iii ◽  
Flow Volume ◽  
Predictive Equations ◽  
Small Airway Disease ◽  
Volume Curve ◽  
Flow Volume Curve ◽  
Forced Expiratory Flow ◽  
Expiratory Flow ◽  
Diagnostic Concordance

BackgroundSpirometry interpretation is influenced by the predictive equations defining lower limit of normal (LLN), while ‘distal’ expiratory flows such as forced expiratory flow at 50% FVC (FEF50) are important functional parameters for diagnosing small airway disease (SAD). Area under expiratory flow-volume curve (AEX) or its approximations have been proposed as supplemental spirometric assessment tools. We compare here the performance of AEX in differentiating between normal, obstruction, restriction, mixed defects and SAD, as defined by Global Lung Initiative (GLI) or National Health and Nutrition Examination Survey (NHANES) III reference values, and using various predictive equations for FEF50.MethodsWe analysed 15 308 spirometry-lung volume tests. Using GLI versus NHANES III LLNs, and diagnosing SAD by the eight most common equation sets for forced expiratory flow at 50% of vital capacity lower limits of normal (FEF50 LLN), we assessed the degree of diagnostic concordance and the ability of AEX to differentiate between various definition-dependent patterns.ResultsConcordance rates between NHANES III and GLI-based classifications were 93.7%, 78.6%, 86.8%, 88.0%, 93.8% and 98.8% in those without, with mild, moderate, moderately severe, severe and very severe obstruction, respectively (agreement coefficient 0.81 (0.80–0.82)). The prevalence of SAD was 0.6%–6.9% of the cohort, depending on the definition used. The AEX differentiated well between normal, obstruction, restriction, mixed pattern and SAD, as defined by most equations.ConclusionsIf the SAD diagnosis is established by using mean FEF50 LLN or a set number of predictive equations, AEX is able to differentiate well between various spirometric patterns. Using the most common predictive equations (NHANES III and GLI), the diagnostic concordance for functional type and obstruction severity is high.

Dynamic mechanisms determine functional residual capacity in mice, Mus musculus

1979 ◽  
Vol 46 (5) ◽  
pp. 867-871 ◽  
Author(s):  
A. Vinegar ◽  
E. E. Sinnett ◽  
D. E. Leith
Keyword(s):  
Tidal Volume ◽  
Functional Residual Capacity ◽  
Flow Volume ◽  
Linear Portion ◽  
Volume Curve ◽  
Flow Volume Curve ◽  
Residual Capacity ◽  
Expiratory Flow ◽  
The Difference ◽  
Pentobarbital Sodium Anesthesia

Awake mice (22.6--32.6 g) were anesthetized intravenously during head-out body plethysmography. One minute after pentobarbital sodium anesthesia, tidal volume had fallen from 0.28 +/- 0.04 to 0.14 +/- 0.02 ml and frequency from 181 +/- 20 to 142 +/- 8. Functional residual capacity (FRC) decreased by 0.10 +/- 0.02 ml. Expiratory flow-volume curves were linear, highly repeatable, and submaximal over substantial portions of expiration in awake and anesthetized mice; and expiration was interrupted at substantial flows that abruptly fell to and crossed zero as inspiration interrupted relaxed expiration. FRC is maintained at a higher level in awake mice due to a higher tidal volume and frequency coupled with expiratory braking (persistent inspiratory muscle activity or increased glottal resistance). In anesthetized mice, the absence of braking, coupled with reductions in tidal volume and frequency and a prolonged expiratory period, leads to FRCs that approach relaxation volume (Vr). An equation in derived to express the difference between FRC and Vr in terms of the portion of tidal volume expired without braking, the slope of the linear portion of the expiratory flow-volume curve expressed as V/V, the time fraction of one respiratory cycle spent in unbraked expiration, and respiratory frequency.

scholarly journals Relationship Between Spontaneous Expiratory Flow-Volume Curve Pattern and Air-Flow Obstruction in Elderly COPD Patients

2013 ◽  
Vol 58 (10) ◽  
pp. 1643-1648 ◽  
Author(s):  
M. Nozoe ◽  
K. Mase ◽  
S. Murakami ◽  
M. Okada ◽  
T. Ogino ◽  
...  
Keyword(s):  
Air Flow ◽  
Flow Volume ◽  
Curve Pattern ◽  
Volume Curve ◽  
Copd Patients ◽  
Flow Volume Curve ◽  
Expiratory Flow

Simulation of the effects of mechanical nonhomogeneities on expiratory flow from human lungs

1990 ◽  
Vol 68 (6) ◽  
pp. 2550-2563 ◽  
Author(s):  
R. K. Lambert
Keyword(s):  
Fluid Mechanics ◽  
Left Lung ◽  
Flow Volume ◽  
Alveolar Pressure ◽  
Peripheral Airways ◽  
Volume Curve ◽  
Human Lungs ◽  
Flow Volume Curve ◽  
Expired Gas ◽  
Expiratory Flow

A computational model for expiration from lungs with mechanical nonhomogeneities was used to investigate the effect of such nonhomogeneities on the distribution of expiratory flow and the development of alveolar pressure differences between regions. The nonhomogeneities used were a modest constriction of the peripheral airways and a 50% difference in compliance between regions. The model contains only two mechanically different regions but allows these to be as grossly distributed as left lung-right lung or to be distributed as a set of identical pairs of parallel nonhomogeneous regions with flows from each merging in a specified bronchial generation. The site of flow merging had no effect on the flow-volume curve but had a significant effect on the development of alveolar pressure differences (delta PA). With the peripheral constriction, greater values of delta PA developed when flows were merged peripherally rather than centrally. The opposite was true in the case of a compliance nonhomogeneity. The delta PA values were smaller at submaximal flows. Plots of delta PA vs. lung volume were similar to those obtained experimentally. These results were interpreted in terms of the expression used for the fluid mechanics of the merging flows. delta PA was greater when the viscosity of the expired gas was increased or when its density was reduced. Partial forced expirations were shown to indicate the presence of mechanical nonhomogeneity.

scholarly journals Shape Analysis of the Maximal Expiratory Flow Volume Curve Among the Patients with Various Kind of Pulmonary Diseases

1982 ◽  
Vol 29 (1) ◽  
pp. 30-36
Author(s):  
Song Hyun Nam ◽  
Hyun Ha Park ◽  
Re Hwe Kim ◽  
Sung Koo Han ◽  
Ye Won Kim ◽  
...  
Keyword(s):  
Shape Analysis ◽  
Pulmonary Diseases ◽  
Flow Volume ◽  
Maximal Expiratory Flow ◽  
Volume Curve ◽  
Flow Volume Curve ◽  
Expiratory Flow

scholarly journals Longitudinal Examination of the Shape of the Maximum Expiratory Flow‐Volume Curve in Young Adults Following SARS‐CoV‐2 Infection

2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Jonathon Stickford ◽  
Marc Augenreich ◽  
Valesha Province ◽  
Nina Stute ◽  
Abigail Stickford ◽  
...  
Keyword(s):  
Young Adults ◽  
Flow Volume ◽  
Volume Curve ◽  
Maximum Expiratory Flow ◽  
Flow Volume Curve ◽  
Expiratory Flow ◽  
Longitudinal Examination

The Shape of the Maximum Expiratory Flow Volume Curve

CHEST Journal ◽  
1988 ◽  
Vol 94 (4) ◽  
pp. 799-806 ◽  
Author(s):  
Mary C. Kapp ◽  
E.Neil Schachter ◽  
Gerald J. Beck ◽  
Lucinda R. Maunder ◽  
Theodore J. Witek
Keyword(s):  
Flow Volume ◽  
Volume Curve ◽  
Maximum Expiratory Flow ◽  
Flow Volume Curve ◽  
Expiratory Flow

Spirometry and Maximal Expiratory Flow-Volume Curve Reference Standards for Polynesian, European, and Chinese Teenagers

CHEST Journal ◽  
1988 ◽  
Vol 94 (4) ◽  
pp. 792-798 ◽  
Author(s):  
Françoise Neukirch ◽  
René Chansin ◽  
Renata Liard ◽  
Monique Levallois ◽  
Philippe Leproux
Keyword(s):  
Reference Standards ◽  
Flow Volume ◽  
Maximal Expiratory Flow ◽  
Volume Curve ◽  
Flow Volume Curve ◽  
Expiratory Flow
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