Relationship between Forced Expiratory Flow and Tracheal Sounds

Respiration ◽  
1988 ◽  
Vol 54 (2) ◽  
pp. 78-88 ◽  
Author(s):  
Masashi Mori ◽  
Mariko Ono ◽  
Tetsuya Hisada ◽  
Hiroyoshi Kino ◽  
Mari Iguchi ◽  
...  
Keyword(s):  
Forced Expiratory Flow ◽  
Tracheal Sounds ◽  
Expiratory Flow

Breathing at low lung volumes and chest strapping: a comparison of lung mechanics

1981 ◽  
Vol 50 (3) ◽  
pp. 650-657 ◽  
Author(s):  
N. J. Douglas ◽  
G. B. Drummond ◽  
M. F. Sudlow
Keyword(s):  
Lung Volume ◽  
Maximum Flow ◽  
Normal Subjects ◽  
Lung Mechanics ◽  
Lung Volumes ◽  
Flow Rates ◽  
Recoil Pressure ◽  
Forced Expiratory Flow ◽  
Expiratory Flow ◽  
Expiratory Flow Rates

In six normal subjects forced expiratory flow rates increased progressively with increasing degrees of chest strapping. In nine normal subjects forced expiratory flow rates increased with the time spent breathing with expiratory reserve volume 0.5 liters above residual volume, the increase being significant by 30 s (P less than 0.01), and flow rates were still increasing at 2 min, the longest time the subjects could breathe at this lung volume. The increase in flow after low lung volume breathing (LLVB) was similar to that produced by strapping. The effect of LLVB was diminished by the inhalation of the atropinelike drug ipratropium. Quasistatic recoil pressures were higher following strapping and LLVB than on partial or maximal expiration, but the rise in recoil pressure was insufficient to account for all the observed increased in maximum flow. We suggest that the effects of chest strapping are due to LLVB and that both cause bronchodilatation.

Forced Expiratory Flow in Uninfected Infants and Children Born to HIV-infected Mothers

2001 ◽  
Vol 163 (4) ◽  
pp. 865-873 ◽  
Author(s):  
ANDREW A. COLIN ◽  
J. SUNIL RAO ◽  
XIN C. CHEN ◽  
JANICE M. HUNTER ◽  
JOHN HANRAHAN ◽  
...  
Keyword(s):  
Infants And Children ◽  
Forced Expiratory Flow ◽  
Expiratory Flow

Modeling expiratory flow from excised tracheal tube laws

1999 ◽  
Vol 87 (5) ◽  
pp. 1973-1980 ◽  
Author(s):  
Nikolai Aljuri ◽  
Lutz Freitag ◽  
José G. Venegas
Keyword(s):  
Static Pressure ◽  
Pressure Recovery ◽  
High Frequency Ventilation ◽  
Flow Limitation ◽  
Flow Conditions ◽  
Expiratory Flow Limitation ◽  
Elastic Tubes ◽  
Viscous Losses ◽  
Forced Expiratory Flow ◽  
Expiratory Flow

Flow limitation during forced exhalation and gas trapping during high-frequency ventilation are affected by upstream viscous losses and by the relationship between transmural pressure (Ptm) and cross-sectional area ( A tr) of the airways, i.e., tube law (TL). Our objective was to test the validity of a simple lumped-parameter model of expiratory flow limitation, including the measured TL, static pressure recovery, and upstream viscous losses. To accomplish this objective, we assessed the TLs of various excised animal tracheae in controlled conditions of quasi-static (no flow) and steady forced expiratory flow. A tr was measured from digitized images of inner tracheal walls delineated by transillumination at an axial location defining the minimal area during forced expiratory flow. Tracheal TLs followed closely the exponential form proposed by Shapiro (A. H. Shapiro. J. Biomech. Eng. 99: 126–147, 1977) for elastic tubes: Ptm = K p[( A tr/ A tr0)− n − 1], where A tr0 is A tr at Ptm = 0 and K p is a parametric factor related to the stiffness of the tube wall. Using these TLs, we found that the simple model of expiratory flow limitation described well the experimental data. Independent of upstream resistance, all tracheae with an exponent n < 2 experienced flow limitation, whereas a trachea with n > 2 did not. Upstream viscous losses, as expected, reduced maximal expiratory flow. The TL measured under steady-flow conditions was stiffer than that measured under expiratory no-flow conditions, only if a significant static pressure recovery from the choke point to atmosphere was assumed in the measurement.

scholarly journals Viscoelasticity of the trachea and its effects on flow limitation

2006 ◽  
Vol 100 (2) ◽  
pp. 384-389 ◽  
Author(s):  
Nikolai Aljuri ◽  
Jose G. Venegas ◽  
Lutz Freitag
Keyword(s):  
Wave Speed ◽  
Mathematical Representation ◽  
Forced Expiration ◽  
Flow Limitation ◽  
Time Dependency ◽  
Cross Sectional ◽  
Elastic Tubes ◽  
Forced Expiratory Flow ◽  
Expiratory Flow ◽  
The Relationship

To test the hypothesis that peak expiratory flow is determined by the wave-speed-limiting mechanism, we studied the time dependency of the trachea and its effects on flow limitation. For this purpose, we assessed the relationship between transmural pressure and cross-sectional area [the tube law (TL)] of six excised human tracheae under controlled conditions of static (no flow) and forced expiratory flow. We found that TLs of isolated human tracheae followed quite well the mathematical representation proposed by Shapiro (Shapiro AH. J Biomech Eng 99: 126–147, 1977) for elastic tubes. Furthermore, we found that the TL measured at the onset of forced expiratory flow was significantly stiffer than the static TL. As a result, the stiffer TL measured at the onset of forced expiratory flow predicted theoretical maximal expiratory flows far greater than those predicted by the more compliant static TL, which in all cases studied failed to explain peak expiratory flows measured at the onset of forced expiration. We conclude that the observed viscoelasticity of the tracheal walls can account for the measured differences between maximal and “supramaximal” expiratory flows seen at the onset of forced expiration.

Volume history and effect on airway reactivity in infants and adults

2002 ◽  
Vol 93 (3) ◽  
pp. 1069-1074 ◽  
Author(s):  
A. Weist ◽  
T. Williams ◽  
J. Kisling ◽  
C. Clem ◽  
R. S. Tepper
Keyword(s):  
Vital Capacity ◽  
Healthy Adults ◽  
Airway Hyperreactivity ◽  
Airway Reactivity ◽  
Maximal Expiratory Flow ◽  
Healthy Infants ◽  
Forced Expiratory Flow ◽  
Residual Capacity ◽  
Expiratory Flow ◽  
Volume History

Volume history is an important determinant of airway responsiveness. In healthy adults undergoing airway challenge, deep inspiration (DI) provides bronchodilating and bronchoprotective effects; however, the effectiveness of DI is limited in asthmatic adults. We hypothesized that, when assessed under similar conditions, healthy infants have heightened airway reactivity compared with healthy adults and that the effectiveness of DI is limited in infants. We compared the effect of DI on reactivity by using full (DI) vs. partial (no DI) forced-expiratory maneuvers on 2 days in supine, healthy nonasthmatic infants (21) and adults (10). Reactivity was assessed by methacholine doses that decreased forced expiratory flow after exhalation of 75% forced vital capacity during a full maneuver and maximal expiratory flow at functional residual capacity during a partial maneuver by 30% from baseline. Reactivity in adults increased when DI was absent, whereas infants' reactivity was unchanged. Infants were more reactive than adults in the presence of DI; however, adult and infant reactivity was similar in its absence. Our findings indicate that healthy infants are more reactive than adults and, like asthmatic adults, do not benefit from DI; this difference may be an important characteristic of airway hyperreactivity.

Effort Independence and Forced Expiratory Flow

CHEST Journal ◽  
1980 ◽  
Vol 77 (2) ◽  
pp. 246-247 ◽  
Author(s):  
Robert E. Hyatt
Keyword(s):  
Forced Expiratory Flow ◽  
Expiratory Flow

Azelastine in the Prophylactic Treatment of Bronchial Asthma: An Italian Multicentre Comparison with Ketotifen

1989 ◽  
Vol 17 (3) ◽  
pp. 218-225 ◽  
Author(s):  
L. Ambrosi ◽  
F. Bariffi ◽  
M. Carino ◽  
E. Catena ◽  
G. Ceccarelli ◽  
...  
Keyword(s):  
Bronchial Asthma ◽  
Double Blind Study ◽  
Double Blind ◽  
Significant Difference ◽  
Effective Prophylaxis ◽  
Daily Dosage Regimen ◽  
Forced Expiratory Flow ◽  
Expiratory Flow ◽  
Low Incidence ◽  
Clinical Measures

The prophylactic effectiveness of the phthalazinone derivative, azelastine was compared with ketotifen. A total of 111 patients, aged 18 – 65 years, from 10 centres was entered into this randomized, double-blind study. All patients had reversible asthma. After 1 week on placebo, patients were allocated to either 8 mg/day azelastine once or twice daily, or to 1 mg ketotifen, twice daily, for a further 12 weeks. Azelastine was more effective in improving respiratory function (forced expiratory flow in 1 s and peak expiratory flow rate) when given in the once daily regimen, whereas clinical measures (number of weekly asthma attacks) were most improved by twice daily dosing. There was no significant difference between the effectiveness of azelastine and that of ketotifen. Treatments were equally well tolerated and a low incidence of side-effects was reported. In conclusion, 8 mg/day azelastine, in either a single or twice daily dosage regimen may be regarded as providing effective prophylaxis against bronchial asthma.

scholarly journals Factors affecting spirometry reference range in growing children

2019 ◽  
Vol 35 (6) ◽  
Author(s):  
Sara Sadiq ◽  
Nadeem Ahmed Rizvi ◽  
Fahad Khalid Soleja ◽  
Muaz Abbasi
Keyword(s):  
Reference Range ◽  
Forced Expiratory Volume ◽  
P Value ◽  
Strong Positive Correlation ◽  
Linear Regression Models ◽  
Factors Affecting ◽  
Independent Variables ◽  
Creative Commons ◽  
Forced Expiratory Flow ◽  
Expiratory Flow

Objectives: To find out the association of weight, height and age with spirometry variables and to generate a regression equation by taking weight as an independent variable beside age and height among children and adolescents of Karachi. Methods: A modified form of ISSAC questionnaire was used. The spirometry variables recorded were Forced vital capacity (FVC), Forced expiratory volume in 1 second (FEV1), FEV1/FVC, Peak expiratory flow rate (PEF), Forced expiratory flow between 25% and 75% expired volume (FEF25-75). A person’s correlation coefficient among boys and girls were calculated for all spirometry variable considering age, height and weight as independent variables. The linear regression models were calculated. Results: The results reported a linear correlation of lung function variables with all three independent variables (i.e. p-value = 0.000), in which age and height manifested a strong positive correlation while weight reported a moderately significant correlation. All spirometry variables such as FVC, FEV1, PEF and FEF25-75 reported a significant coefficient of dependency and coefficient of correlation individually with age, height and weight. Conclusion: It is concluded that beside age, height and weight both also have significant correlation with lung volumes so these should be taken into account when using spirometry as a diagnostic test. doi: https://doi.org/10.12669/pjms.35.6.1212 How to cite this:Sadiq S, Rizvi NA, Soleja FK, Abbasi M. Factors affecting spirometry reference range in growing children. Pak J Med Sci. 2019;35(6):1587-1591. doi: https://doi.org/10.12669/pjms.35.6.1212 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

scholarly journals The Value of Spirometry in Subglottic Stenosis

2019 ◽  
Vol 98 (2) ◽  
pp. 98-101 ◽  
Author(s):  
Alhelali Abdullah ◽  
A. Alrabiah ◽  
Sayed S. Habib ◽  
Y. Aljathlany ◽  
A. Aljasser ◽  
...  
Keyword(s):  
Upper Airway ◽  
Forced Expiratory Volume ◽  
Endoscopic Examination ◽  
Subglottic Stenosis ◽  
King Saud University ◽  
Medical City ◽  
Forced Expiratory Flow ◽  
Surgery Outcomes ◽  
Expiratory Flow ◽  
Grade 3

The diagnosis of subglottic stenosis (SGS) is usually made by clinical assessment and definitively by a direct endoscopic examination. This study aimed to evaluate different spirometric values in relation to anatomical grading and severity of subglottic stenosis cases of upper airway obstruction. Cases of SGS that underwent dilatational procedures endoscopically at the otolaryngology department of the King Saud University Medical City, Riyadh, Saudi Arabia, from June 2015 to October 2017 were collected. Pulmonary function test (PFT) pre- and postoperative parameters and the grades of subglottic stenosis were extracted. We compared different spirometric values to the severity of SGS and compared the pre- and postoperative results for each patient. There were 19 cases with a valid PFT study within 7 days preoperatively in addition to a documented intraoperative grading according to the Myer-Cotton grading system; 7 (36.8%) were grade 1, 8 (42.1%) were grade 2, and 4 (21.1%) were grade 3. The actual preoperative ratio of forced expiratory volume (FEV1) in 1 second to peak expiratory flow (PEF) for all 19 patients ranged from 7.34 to 21.40 mL/L/min. We found a significant improvement in all spirometric parameters postdilatation including PEF ( P < .001), FEV1 ( P < .001), FEV1/PEF ( P = .001), forced expiratory flow (FEF) from 25%, 50%, and 75% of vital capacity, respectively, FEF25 ( P < .001), FEF50 ( P = .001), FEF75 ( P = .048), and maximum mid-expiratory flow ( P = .002). We did not find any correlation between the severity of stenosis and spirometric values. This study revealed that spirometry is a useful marker in following up patients with subglottic stenosis and is also a good indicator to determine postairway surgery outcomes. However, these markers do not correlate with anatomical grading and the severity of subglottic stenosis.

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