Cough Efficiency in Cystic Fibrosis
Condition: Cystic Fibrosis
MeSH terms: Cystic Fibrosis; Fibrosis
Study type: Observational

Summary: 
      The major causes of morbidity and mortality in Cystic Fibrosis (CF) are linked to the process
      of chronic inflammatory of the airway, leading to the progressive damage of the small
      bronchioles and subsequently to the proximal bronchi. A connection between weaknesses of
      respiratory muscles in CF and deficits of CFTR in the muscle has been established.
      Insufficient cough in CF patients may advance re-current respiratory infections. A voluntary
      cough flow volume (C-FVC) profile incorporates the characteristics of the forced expiratory
      flow volume curve (FE-VC). The study aims to explore the correspondence of voluntary
      cough-flow-volume and maximum expiratory flow-volume maneuvers in relation to disease
      complications in CF patients.
    

Detailed description: 
      Cystic fibrosis (CF) is the most common lethal life shortening genetic disease caused by
      mutations of the trans-membrane conductance regulator (CFTR) gene. The major causes of
      morbidity and mortality in CF are linked to the process of chronic inflammatory of the
      airway, leading to the progressive damage of the small bronchioles and subsequently to the
      proximal bronchi. Cough is a back-up mechanism for mucus clearance which comes into effect in
      health during emergency situations, such as following the inhalation of a foreign body, and
      in lung disease where often the primary host defense clearance mechanism, namely mucociliany
      clearance, is compromised

      Several studies have showed a connection between weaknesses of respiratory muscles in CF and
      deficits of CFTR in the muscle; sustain infection of pseudomonas; lower than normal tension
      time index and low fat free mass [3-6]. Weakness of the respiratory muscle may insinuate
      insufficient cough in CF patients.

      Effective cough is initiated in several mechanical stages: a) inhaling a variable amount of
      air, b) closure of the glottis, c) contraction of respiratory muscles, and d) forced
      expiration to residual volume [7-13] A voluntary cough flow volume (C-FVC) profile therefore,
      incorporates the characteristics of the forced expiratory flow volume curve (FEVC) in that
      the first "spike" represents the peak cough flow, and the volume exhaled by the cough
      corresponds with the vital capacity. The descending portion of the C-FVC including secondary
      spikes decrease in a linear fashion as lung volume goes down from total lung capacity to
      residual volume.10 similar to the FEVC flow decay. Any disturbance in either of the cough
      stages may impair its efficiency.

      The aim of this study is to explore the information that can be gained on cough ability in a
      group of CF patients, by the performance of voluntary cough-flow-volume maneuver and in
      relation to the characteristics of a maximum expiratory flow-volume curve.

      Study plan How does this advance the field? In this study we wish to evaluate for the first
      time the cough ability derived from the voluntary cough flow volume curve for detection of
      insufficient cough in patients with CF. We hope to show that the cough flow volume curve
      corresponds with changes in cough ability in these patients in relation to lung function
      deterioration.

      What are the clinical implications? An objective following-up of cough ability deterioration
      may allow the opportunity to introduce special respiratory therapy for strengthening cough
      and ease secretion flow in these patients.
    

Observational model: Cohort
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Any CF patient visiting the pulmonary function laboratory, above 8 years old, who could
        cooperate with spirometry and who had no exacerbation, upon signing agreement consent
      
Keywords: Spirometry,; Cough