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Complexity of the Airflow in COPD

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01888705
Recruitment Status : Unknown
Verified June 2013 by Karla Dames, Rio de Janeiro State University.
Recruitment status was:  Recruiting
First Posted : June 28, 2013
Last Update Posted : June 28, 2013
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Rio de Janeiro State Research Supporting Foundation (FAPERJ)
Information provided by (Responsible Party):
Karla Dames, Rio de Janeiro State University

Brief Summary:

Recently, there has been a growing interest in the study of nonlinear dynamics as a methodology for complementary analysis to characterize the respiratory pattern. These methods are well established in studies of heart rate. The analyzes evaluate complex signals, including large-scale fractal correlations and distributions in time series, and can provide relevant clinical information.

Measures such as approximate entropy and sample entropy have shown great potential in the evaluation of the complexity of the respiratory system, providing information relevant to the understanding of physiological and pathophysiological processes. These measures are based on the concept of non-linearity in the presence of a high number of interconnections, resulting in the complex behavior exhibited by physiological systems.

The approximate entropy (ApEn) is related to the amount of clutter, complexity or unpredictability of a data series over time. In a complementary way, the sample entropy (SampEn), is a far more elaborate than the ApEn, to reduce possible biased estimates due to self-similarity.

A study conducted by our group in asthma patients with different levels of bronchial obstruction demonstrated a significant reduction in airflow approximate entropy (ApEnV´) in asthmatic subjects. Investigators believe that in COPD, similar to that which occurs in asthma disorders that are associated with complex changes in the pathophysiology triggering breath control, possibly resulting in changes in air flow (V´).

Considering the development "silent" changes of mechanical ventilation in COPD patients and its clinical relevance, as well as the difficulty of identifying such changes through conventional methods, we observed the need to obtain more detailed information, including the complexity of the system breathing for better understanding of factors that contribute to the illness.

In this context, the objectives of this study were: (1) analyze the influence of airway obstruction in the complexity of the patterns of airflow in patients with COPD, (2) evaluate the diagnostic power of the test in identifying the changes caused by COPD.

Condition or disease

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Study Type : Observational [Patient Registry]
Estimated Enrollment : 90 participants
Time Perspective: Cross-Sectional
Target Follow-Up Duration: 1 Day
Official Title: Complexity of the Airflow at Different Levels of Bronchial Obstruction of COPD.
Study Start Date : March 2010
Estimated Primary Completion Date : July 2013
Estimated Study Completion Date : December 2013

Control group
Group of nonsmokers individuals without respiratory disease.
Smokers wiht normal spirometry.
Patients with COPD level I, mild.
Patients with COPD level II, moderate.
Patients with COPD level III, severe.
Patients with COPD level IV, very severe.

Primary Outcome Measures :
  1. Respiratory Impedance in Different Phases of the Cycle Ventilation in Patients with Chronic Obstructive Pulmonary Disease [ Time Frame: up to 3 years ]
    The aim of the study was to analyze the changes in the respiratory system impedance (Zrs) in the different phases of the respiratory cycle of patients with Chronic Obstructive Pulmonary Disease (COPD). This research was conducted using a monofrequency version of the forced oscillation technique (mFOT) and consisted of a controlled observational study where 31 individuals were analyzed, 8 controls and 23 individuals with COPD. The patients presented different degrees of airway obstruction.

Information from the National Library of Medicine

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Ages Eligible for Study:   40 Years to 90 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

The control group will consist of healthy subjects, nonsmokers, who had no episode of respiratory infection thirty days before the examinations.

The group of patients with COPD will be comprised of individuals treated at the Department of Pneumology (Hospital Universitário Pedro Ernesto), at different levels of airflow obstruction.


Inclusion Criteria:

  • volunteers with COPD for Patients Group;
  • volunteers without any respiratory disease for the control group.

Exclusion Criteria:

  • individuals with history of tuberculosis or other lung disease,
  • heart disease in general and
  • disability in the exams.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01888705

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Laboratório de Instrumentação Biomédica Recruiting
Rio de Janeiro, Brazil, 21550-013
Contact: Karla Dames, Principal Investigator    : (5521)97456496   
Principal Investigator: Karla Dames, MSc.         
Principal Investigator: Pedro L de Melo, DSc.         
Principal Investigator: Agnaldo J Lopes, Dr.         
Sponsors and Collaborators
Rio de Janeiro State University
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Rio de Janeiro State Research Supporting Foundation (FAPERJ)
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Study Director: Pedro L de Melo, DSc. State University of Rio de Janeiro
Additional Information:

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Karla Dames, Professor, Rio de Janeiro State University Identifier: NCT01888705    
Other Study ID Numbers: UERJ-DPOC-01
First Posted: June 28, 2013    Key Record Dates
Last Update Posted: June 28, 2013
Last Verified: June 2013
Keywords provided by Karla Dames, Rio de Janeiro State University:
Entropy Sampling
Respiratory Mechanics