Ventilatory abnormalities in patients with cystic fibrosis undergoing the submaximal treadmill exercise test

Abstract

BackgroundExercise has been studied as a prognostic marker for patients with cystic fibrosis (CF), as well as a tool for improving their quality of life and analyzing lung disease. In this context, the aim of the present study was to evaluate and compare variables of lung functioning. Our data included: (i) volumetric capnography (VCAP) parameters: expiratory minute volume (VE), volume of exhaled carbon dioxide (VCO2), VE/VCO2, ratio of dead space to tidal volume (VD/VT), and end-tidal carbon dioxide (PetCO2); (ii) spirometry parameters: forced vital capacity (FVC), percent forced expiratory volume in the first second of the FVC (FEV1%), and FEV1/FVC%; and (iii) cardiorespiratory parameters: heart rate (HR), respiratory rate, oxygen saturation (SpO2), and Borg scale rating at rest and during exercise. The subjects comprised children, adolescents, and young adults aged 6–25 years with CF (CF group [CFG]) and without CF (control group [CG]).MethodsThis was a clinical, prospective, controlled study involving 128 male and female patients (64 with CF) of a university hospital. All patients underwent treadmill exercise tests and provided informed consent after study approval by the institutional ethics committee. Linear regression, Kruskal–Wallis test, and Mann–Whitney test were performed to compare the CFG and CG. The α value was set at 0.05.ResultsPatients in the CFG showed significantly different VCAP values and spirometry variables throughout the exercise test. Before, during, and after exercise, several variables were different between the two groups; statistically significant differences were seen in the spirometry parameters, SpO2, HR, VCO2, VE/VCO2, PetCO2, and Borg scale rating. VCAP variables changed at each time point analyzed during the exercise test in both groups.ConclusionVCAP can be used to analyze ventilatory parameters during exercise. All cardiorespiratory, spirometry, and VCAP variables differed between patients in the CFG and CG before, during, and after exercise.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-015-0056-5) contains supplementary material, which is available to authorized users.

Modulation of behaviour and virulence of a high alginate expressing Pseudomonas aeruginosa strain from cystic fibrosis by oral commensal bacterium Streptococcus anginosus

“…As in our previously published studies of P . aeruginosa and AGS we chose to examine these interactions in 10% CO 2 because this is particularly relevant to conditions in the cystic fibrosis lung where impaired gaseous exchange is thought to cause the increased levels of alveolar CO 2 observed in the CF lung [ 66 ]. It will be of interest to extend these studies to determine the responses of these strains singly or in combination to a wider range of atmospheric conditions that may be encountered in this disease environment.…”

Use of Volumetric Capnography in Submaximal Exercise Test: What Did We Learn?

“…Among the most relevant results, we note: (i) the volume correlation of forced expiratory volume in one second (FEV 1 ) with the exhaled carbon dioxide production (VCO 2 )-higher FEV 1 values were associated with higher CO 2 V exhaled values during the exercise (p < 0.001); (ii) VCO 2 , EV(exhaled volume) / CO 2 V and PetCO 2 showed differences between groups at all-time points analyzed, demonstrating that CFG retained CO 2 when compared to HS (p < 0.001); (iii) an increased respiratory rate (RR) (p ≤ 0.001) and HR (p ≤ 0.001) in CFG, and a decrease in peripheral oxygen saturation (SpO 2 ) during the exercise (p ≤ 0.001) [2].…”

“…This event requires the inspiratory muscle works at a mechanical disadvantage. During the exercise, there is an increase in oxygen demand to the muscles, with increased demand for the cardiovascular system [2].…”

“…Submaximal tests are essential for evaluating physical capacity and ventilator [2]. As activity of daily living (ADL) for children and adolescents is considered mostly sub-maximal, submaximal tests can be representative of the patient's clinical presentation in his routine.…”

“…In an article published by Parazzi and colleagues [2], we discussed the importance of submaximal exercise with the help of volumetric capnography (VCap) as a tool in the cardiorespiratory evaluation of CF. CF causes physical limitations for patients, minimizing the activities to achieve the maximum effort.…”