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Background: Whereas pulmonary exacerbations and aerobic fitness play a key role in the prognosis of cystic fibrosis (CF), the use of ventilatory threshold data as markers of exacerbation risk has been scarcely addressed. This study sought to examine the association between aerobic fitness, assessed through ventilatory threshold variables recorded during cardiopulmonary exercise testing (CPET), and the risk of exacerbations in individuals with CF., Methods: Participants of this retrospective cohort study were subjects from 6 y of age. Over a 4-y period, the following data were recorded: lung function indicators, CPET variables, time to first exacerbation and antibiotic use, along with demographic, clinical, and anthropometric data., Results: The mean age of 20 subjects included was 16 ± 5.4 y. Univariate regression analysis revealed that lung function (FEV 1 : Cox hazard ratio [HR] 0.97, P = .03; and forced expiratory flow between 25-75% of vital capacity [FEF 25-75 ]: Cox HR 0.98, P = .036) and aerobic fitness (oxygen consumption [V̇ O 2 ] at ventilatory threshold: Cox HR 0.94, P = .01; and ventilatory equivalent for carbon dioxide [V̇ E /V̇ CO 2 ] at ventilatory threshold: Cox HR 1.13, P = .049) were associated with exacerbation risk, whereas in the multivariate model, only V̇ O 2 at the ventilatory threshold (%max) (Cox HR 0.92, P = .01) had a significant impact on this risk. Consistently, individuals experiencing exacerbation had significantly lower V̇ O 2 values (%max) at the ventilatory threshold ( P = .050) and higher ventilatory equivalent for oxygen consumption (V̇ E /V̇ O 2 ) ( P = .040) and V̇ E /V̇ O 2 ( P = .037) values at the ventilatory threshold. Time to exacerbation was significantly correlated with V̇ O 2 at the ventilatory threshold (r = 0.50, P = .02), V̇ E /V̇ O 2 (r = -0.48, P = .02), and V̇ E /V̇ CO 2 (r = -0.50, P = .02)., Conclusions: Our results suggest an association between CPET variables at the ventilatory threshold and exacerbations. Percentage V̇ O 2 at the ventilatory threshold could serve as a complementary variable to monitor exacerbations in people with CF., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2023 by Daedalus Enterprises.)

Background: No studies have investigated the use and safety of high-frequency chest wall compression (HFCWC) for non-hospitalized infants with acute viral bronchiolitis (AVB). The aim of the present study was to evaluate the immediate effects and safety of HFCWC as compared to airway clearance techniques in children with AVB., Methods: In this randomized clinical trial in non-hospitalized infants (0-12 months old) with mild to moderate AVB, children were randomized into 2 groups: airway clearance techniques (20 min of prolonged slow expiration and provoked cough) or HFCWC (15 min). A single session was performed and children were evaluated at baseline and at 10 min and 20 min after treatments. Outcomes measures were the Wang severity score, [Formula: see text], sputum wet-weight, and the presence of adverse events., Results: A total of 91 infant subjects, mean age 7.9 ± 2.6 months, were included. Significant ( P = .004) between-group differences were found in the Wang score, which was 0.28 points lower in the airway clearance techniques group. There was a greater increase of infants classified as normal and a greater decrease of those classified as mild according to the Wang score when airway clearance techniques were used compared to the use of HFCWC ( P = .009). The sputum wet-weight was lower in subjects treated with the airway clearance techniques ( P < .001). Although [Formula: see text]improved in both groups, no differences were found between them. There was also no difference for adverse events, and the majority of children did not present any adverse events after 20 min., Conclusions: The use of HFCWC induced similar clinical effects as airway clearance techniques and was safe for non-hospitalized infants with AVB. Both techniques reduced respiratory symptoms and acutely improved [Formula: see text]. (ClinicalTrials.gov: NCT03835936.)., Competing Interests: Dr Donadio is supported in part by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior and Conselho Nacional de Desenvolvimento Científico e Tecnológico. The other authors have disclosed no conflicts of interests., (Copyright © 2021 by Daedalus Enterprises.)

Background: Patients with cystic fibrosis develop decreased exercise capacity. However, the main factors responsible for this decline are still unclear. Thus, the objective of this study was to evaluate the factors influencing exercise capacity assessed with the modified shuttle test (MST) in individuals with cystic fibrosis., Methods: A cross-sectional study was carried out in subjects with a diagnosis of cystic fibrosis who were 6-26 y old and were regularly monitored at 2 cystic fibrosis reference centers in Brazil. Individuals who were unable to perform the tests or who exhibited hemodynamic instability and exacerbation of respiratory symptoms were excluded. Anthropometric, clinical, and genotype data were collected. In addition, lung function and exercise capacity were evaluated with the MST., Results: 73 subjects (mean age 12.2 ± 4.9 y and FEV 1 76.8 ± 23.3%) were included. The mean distance achieved in the MST was 765 ± 258 m (71.6% of predicted). The distance achieved on the MST correlated significantly with age (r = 0.49, P < .001), body mass index (r = 0.41, P < .001), resting heart rate (r = -0.51, P < .001), and FEV 1 (r = 0.24, P = .042). Subjects with FEV 1 > 67% of predicted ( P = .02) and those with resting heart rate < 100 beats/min ( P = .01) had a greater exercise capacity. Resting heart rate, age, and FEV 1 (%) were found as significant variables to explain the distance achieved on the MST (R 2 = 0.48, standard error = 191.0 m)., Conclusions: The main determinants of exercise capacity assessed with the MST in individuals with cystic fibrosis were resting heart rate, age, and lung function., (Copyright © 2020 by Daedalus Enterprises.)

Background: Aerobic fitness, as measured by peak oxygen uptake (V̇ O 2 peak), correlates with survival in children and adults with cystic fibrosis (CF). We sought to evaluate the effects of V̇ O 2 peak on mortality rates in subjects with CF., Methods: An online search in PubMed, Embase, LILACS, and SciELO databases was conducted, and cohort studies that assessed mortality rates after oxygen absorption measurements during a maximal exercise test were included. Data were extracted independently by 2 reviewers. The quality analysis of the selected articles was performed using the Newcastle-Ottawa scale. The main outcome evaluated was the mortality of subjects with CF. Whenever possible, and if appropriate, a random effect meta-analysis was performed., Results: Six cohort studies were included in this systematic review including 551 subjects. Five studies were classified with high methodological quality. Two analyses were carried out to evaluate the influence of V̇ O 2 peak on mortality. Total difference standardized mean between V̇ O 2 peak averages in the survival or non-survival groups was -0.606 (95% CI = -0.993 to -0.219, P = .002). In addition, subjects with a lower V̇ O 2 peak had a significantly higher mortality risk (relative risk 4.896, 95% CI = 1.086 to 22.072, P = .039) in an 8-y follow-up period., Conclusion: Low levels of peak oxygen uptake are associated with an increase of 4.9 in the risk of mortality in subjects with CF. This indicates that V̇ O 2 could be an important follow-up variable to measure, in addition to FEV 1 ., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2019 by Daedalus Enterprises.)