%0 Journal Article
%T Expiratory Flow Limitation and Its Relation to Dyspnea and Lung Hyperinflation in Patients with Chronic Obstructive Pulmonary Disease: Analysis Using the Forced Expiratory Flow-Volume Curve and Critique
%A Billy Peng
%A Matthew Miller
%A Mark Slootsky
%A Ravi Patel
%A Ahmet Baydur
%J Open Journal of Respiratory Diseases
%P 91-104
%@ 2163-9418
%D 2021
%I Scientific Research Publishing
%R 10.4236/ojrd.2021.113009
%X <b>Background:</span></b><span style=\"font-family:&quot;\"><span style=\"font-family:Verdana;\"> Tidal expiratory flow limitation (tEFL) is defined as absence of
increase in air flow during forced expiration compared to tidal breathing and
is related to dyspnea at rest and minimal exertion in patients with chronic
airflow limitation (CAL). Tidal EFL has not been expressed as a continuous
variable (0% - 100%) in previous analyses. </span><b><span style=\"font-family:Verdana;\">Objective:</span></b><span style=\"font-family:Verdana;\"> To relate the
magnitude of tEFL to spirometric values and Modified Medical Research Council
(MMRC) score and Asthma Control Test (ACT). </span><b><span style=\"font-family:Verdana;\">Methods:</span></b><span style=\"font-family:Verdana;\"> Tidal EFL was computed as percent of the tidal
volume (0% - 100%) spanned (intersected) by the forced expiratory-volume curve. </span><b><span style=\"font-family:Verdana;\">Results: </span></b><span style=\"font-family:Verdana;\">Of 353 patients
screened, 192 (114 M, 78 F) patients (136 with COPD, 56 with asthma) had CAL.
Overall characteristics: (mean ¡À SD) age 59 ¡À 11 years, BMI 28 ¡À 7, FVC (%
pred) 85 ¡À 20, FEV1 (% pred) 66 ¡À 21, FEV1/FVC 55% ¡À 10%, RV (% pred) 147 ¡À 42.
Tidal EFL in patients with tEFL was 53% ¡À 39%. Using univariate analysis,
strongest correlations were between tEFL and FVC and between tEFL and RV in
patients with BMI &lt; 30 kg/m</span><sup><span style=\"font-family:Verdana;\">2</span></sup><span style=\"font-family:Verdana;\">. In patients with nonreversible CAL,
tEFL was positively associated with increasing MMRC, negatively with
spirometric measurements, and positively with RV/TLC. In asthmatics, ACT scores
were higher in patients with mean BMI ¡Ý 28 kg/m</span><sup><span style=\"font-family:Verdana;\">2</span></sup><span style=\"font-family:Verdana;\"> (p &lt; 0.00014)
and RV/TLC values &gt; 40% (p &lt; 0.03). </span><b><span style=\"font-family:Verdana;\">Conclusions:</span></b><span style=\"font-family:Verdana;\"> Dyspnea is strongly associated with tEFL and
lung function, particularly in patients with nonreversible CAL. Air trapping
and </span><span style=\"font-family:Verdana;\">BMI contribute to tEFL.
%K Air Trapping
%K Asthma
%K Chronic Obstructive Pulmonary Disease
%K Dyspnea
%K Forced Expiratory Flow-Volume Curve
%K Hyperinflation
%K Tidal Expiratory Flow Limitation
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=111448