Resting respiratory variables and exercise capacity in adult patients with cystic fibrosis

SummaryIntroductionCystic fibrosis (CF) is the most common life-limiting, recessively inherited disease in the white population, associated with significantly high morbidity and mortality rates; CF pulmonary disease, assessed by pulmonary function tests, arterial blood gases and the Schwachman score, remains the most prevalent in terms of morbidity in the adult CF population.ObjectivesThe aim of the present study was to evaluate the relationship between resting respiratory variables and exercise capacity in adult patients with CF.ResultsStudy investigations undertaken in 18 CF patients and 11 healthy volunteers showed that among the resting lung function parameters, inspiratory capacity (IC) at rest was the only significant predictor of VO2 peak (r=0.67, p<0.007) and VO2/t-slope (r=0.86, p<0.0001). The percentage of predicted FEV1 in adult CF patients was 77±33% pred. vs 104±16% pred. in healthy subjects (p<0.006); the corresponding percentage of IC at rest was 82±36% pred. in patients vs 116±20% pred. in healthy (p<0.003). CF patients presented with a significantly prolonged rapid breathing after exercise (32br per minute at recovery for CF vs 22 for healthy; p