Respiratory muscle function in cystic fibrosis.

Area of Science:

• Respiratory Medicine
• Pulmonology
• Muscle Physiology

Background:

• Cystic fibrosis (CF) is a genetic disorder affecting multiple organs, primarily the lungs.
• Respiratory muscle weakness can be a complication in CF patients, potentially impacting lung function.
• Assessing peripheral muscle strength alongside respiratory muscle strength is crucial for a comprehensive understanding of CF pathophysiology.

Purpose of the Study:

• To evaluate maximal static expiratory and inspiratory mouth pressures (PEmax and PImax) in young adults with cystic fibrosis.
• To assess the strength of the quadriceps femoris muscle in the same patient cohort.
• To determine the potential contribution of respiratory and peripheral muscle weakness to the respiratory problems in cystic fibrosis.

Main Methods:

• Maximal static expiratory mouth pressure (PEmax) and inspiratory mouth pressure (PImax) were measured.
• Quadriceps femoris muscle strength was assessed.
• Measurements were taken in 25 patients aged 16-28 years with cystic fibrosis (mean FEV1 46% predicted).

Main Results:

• Mean PEmax was 64% (18%) predicted, with 16 out of 25 patients below 75% predicted.
• Mean PImax was 64% (24%) predicted, with 14 out of 25 patients below 75% predicted.
• Quadriceps muscle strength averaged 68% (20%) predicted, with 17 out of 25 patients below 75% predicted.

Conclusions:

• Young cystic fibrosis patients exhibit reduced respiratory muscle strength (PEmax and PImax) and peripheral muscle strength (quadriceps).
• The observed reductions in muscle strength were relatively small and unlikely to be a major factor in the patients' respiratory problems.
• Further research may explore the long-term implications of muscle weakness in CF and potential interventions.