Respiratory muscle strength in stable adolescent and adult patients with cystic fibrosis.
BACKGROUND
Since available studies have provided conflicting results, this study investigated respiratory muscle function and its relationship with exercise capacity, degree of dyspnoea and leg discomfort, and quality of life in patients with Cystic Fibrosis (CF).


METHODS
Using a cross-sectional design, 27 clinically stable adolescent and adult patients (f/m: 14/13, age: 26+/-7 years) were included. Data of respiratory muscle strength (P(i)max and P(e)max), lung function (spirometry), peripheral muscle strength (peak isometric quadriceps and hand-grip strength), symptom-limited exercise capacity (modified shuttle test, MST), post-exercise dyspnoea and leg discomfort (Borg scores), and quality of life (CFQ-14+, MRC) were obtained for further analysis.


RESULTS
P(i)max of the total patient group was significantly higher than reference values (P(i)max=124+/-32% predicted), and correlated positively with the walk/run distance of the MST (r(s)=0.59, p=0.00). Female patients showed more dyspnoea and a more impaired lung function than male patients. However, P(i)max and P(e)max (% predicted) showed a tendency to be higher in female than in male patients.


CONCLUSIONS
Increased work of breathing will have a conditioning effect on the respiratory muscles, suggesting that training-related inspiratory muscle strength can play a positive role in the limited exercise capacity of CF patients.
Dunnink
M A
MA
Cystic Fibrosis Centre Utrecht, University Medical Centre Utrecht, PO Box 85500, 3508 GA Utrecht, The Netherlands.
Doeleman
W R
WR
Trappenburg
J C A
JC
de Vries
W R
WR
D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000175:diagnosis / Q000503:physiopathology*; D004417:Dyspnea; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008297:Male; D053580:Muscle Strength; D005082:Physical Exertion; D011788:Quality of Life; D015656:Respiratory Mechanics; D012132:Respiratory Muscles / Q000503:physiopathology*; D012137:Respiratory System / Q000503:physiopathology*; D012737:Sex Factors; D013147:Spirometry; D055815:Young Adult