Ventilatory Threshold and Risk of Pulmonary Exacerbations in Cystic Fibrosis.

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 (FEV1: Cox hazard ratio [HR] 0.97, P = .03; and forced expiratory flow between 25-75% of vital capacity [FEF25-75]: Cox HR 0.98, P = .036) and aerobic fitness (oxygen consumption [V̇O2 ] at ventilatory threshold: Cox HR 0.94, P = .01; and ventilatory equivalent for carbon dioxide [V̇E/V̇CO2 ] at ventilatory threshold: Cox HR 1.13, P = .049) were associated with exacerbation risk, whereas in the multivariate model, only V̇O2 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 V̇O2 values (%max) at the ventilatory threshold (P = .050) and higher ventilatory equivalent for oxygen consumption (V̇E/V̇O2 ) (P = .040) and V̇E/V̇O2 (P = .037) values at the ventilatory threshold. Time to exacerbation was significantly correlated with V̇O2 at the ventilatory threshold (r = 0.50, P = .02), V̇E/V̇O2 (r = -0.48, P = .02), and V̇E/V̇CO2 (r = -0.50, P = .02). CONCLUSIONS: Our results suggest an association between CPET variables at the ventilatory threshold and exacerbations. Percentage V̇O2 at the ventilatory threshold could serve as a complementary variable to monitor exacerbations in people with CF.

The Association of Field Test Outcomes with Peak Oxygen Uptake in Patients with Cystic Fibrosis: A Systematic Review.

The purpose of the study was to evaluate the association of field test outcomes with peak oxygen uptake (VO2peak) in patients with cystic fibrosis (CF) and to describe the main prediction equations available. Data searches were performed in five databases (Pubmed, Embase, LILACs, Scopus and Web of Science) and also in the reference lists of articles included. The following inclusion criteria were used: studies including individuals with CF, presenting both a field test and a cardiopulmonary exercise testing (CPET), and describing a predictive equation or coefficient of correlation/determination. Case studies, abstracts, letters of reply, editorials and duplicate publications were excluded. The methodological quality analysis was performed using the JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies scale. Protocol registration number: CRD42020148363. Ten studies were eligible. Five equations were found to predict VO2peak. Equations derived from the shuttle tests (ST) showed strong correlations with VO2peak (r = 0.79 to 0.95). The six-minute walk test (6MWT) showed moderate associations with VO2peak in participants with moderate disease severity (r = 0.53 to 0.65). Furthermore, patients with lower maximum heart rate on the three-minute step test tended to have a higher percent predicted VO2peak (r = -0.40), and the one-minute sit-to-stand test demonstrated moderate correlations between VO2peak and the number of repetitions (r = 0.52 to 0.66). In conclusion, field test outcomes correlate with oxygen consumption assessed through CPET, although only the ST seems to be valid as a predictor of VO2peak in patients with CF.

Prediction of peak oxygen uptake using the modified shuttle test in children and adolescents with cystic fibrosis.

BACKGROUND: Several tests may be used to assess exercise intolerance in cystic fibrosis (CF), including the gold standard cardiopulmonary exercise test (CPET) and the Modified Shuttle Test (MST). OBJECTIVE: To evaluate the use of the MST as a predictor of peak oxygen uptake (VO2 peak) and to compare VO2 peak and maximal heart rate (HRmax) obtained in both tests. METHODS: Cross-sectional study including individuals with CF aged between 6 and 20 years old. Participants who were unable to perform the tests and/or presented signs of pulmonary exacerbation were excluded. Demographic, anthropometric, clinical and spirometric values ​​were collected. CPET and the MST were performed in two consecutive outpatient visits. HRmax, peripheral oxygen saturation, dyspnea, and VO2 peak measured and estimated were compared. RESULTS: Twenty-four patients, mean age 15.7 ± 4.2 years and FEV1 (% predicted) 76.4 ± 23.8, were included. Mean values ​​of HRmax (bpm) and HRmax in percent of predicted (HRmax%) were lower (P = 0.01) in the MST (171.6 ± 14.5 and 87.1 ± 7.5) compared to CPET (180.9 ± 10.0 and 91.9 ± 5.4). However, there was no significant differences between tests in the variation (delta) for HRmax and HRmax% (P = 0.17). A strong correlation (r = 0.79; P < 0.0001) was found between distance achieved (MST) and VO2 peak (CPET). The regression model to estimate VO2 peak resulted in the following equation: VO2 (mL · kg-1 · min-1 ) = 20.301 + 0.019 × MST distance (meters). There was no difference (P = 0.50) between VO2 peak measured (CPET) and estimated by the equation. CONCLUSION: The MST may be an alternative method to evaluate exercise capacity and to predict VO2 peak in children and adolescents with CF.

Predictive maximal heart rate equations in child and adolescent athletes: a systematic review / Equações preditivas de frequência cardíaca máxima em crianças e adolescentes atletas: uma revisão sistemática / Ecuaciones predictivas de frecuencia cardíaca máxima en niños y adolescentes atletas: una revisión sistemática

Abstract Introduction: The maximal heart rate (HRmax) is considered the highest value of HR achieved during a physical effort close to exhaustion. Objective: To evaluate the applicability of the predictive HRmax equations during exercise tests in child and adolescent athletes through a systematic review. Methods: It is a systematic review, through Scopus, Pubmed, Lilacs, Scielo and PEDro. The included studies compared the measured and estimated HRmax predictive equations during exercise tests in child and adolescent athletes. The following search strategy was used: "Exercise test OR Exercise testing OR Cardiopulmonary exercise test OR Cardiopulmonary exercise testing OR Peak oxygen uptake OR Maximal oxygen consumption OR Exercise capacity OR Heart rate OR Heart rate OR Pulse rate OR Pulse rates OR Heart rate control OR Cardiac chronotropic OR Predictive value test AND Predictive equations". Results: From a total of 1,664 articles, only 4 were included. All compared the measured HRmax values with those estimated by the "220 - age" equation; 3 used the formula "208 - (0.7 x age)", and only 1 used the "223 - (1.44 x age)" equation. Although all of them stated that the "220 - age" equation overestimates HRmax, the formula "208 - (0.7 x age") underestimated (2 articles) and overestimated (1 study) the measured results, while the equation "213 - (1.44 x age) was also not adequate. Conclusion: The use of predictive HRmax equations for child and adolescent athletes does not seem to be recommended. The use of cohort points for these estimates is carefully recommended.

Resumo Introdução: A frequência cardíaca máxima (FCmáx) é denominada o maior valor de FC alcançada durante um esforço físico intenso. Objetivo: Avaliar a aplicabilidade das equações preditivas de FCmáx durante testes de exercício em crianças e adolescentes atletas. Métodos: Trata-se de uma revisão sistemática, através do Scopus, Pubmed, Lilacs, Scielo e PEDro. Foram incluídos estudos que compararam a FCmáx medida e a estimada por equações preditivas durante testes de exercício em crianças e adolescentes atletas. Utilizou-se a seguinte estratégia de busca: "Exercise test OR Exercise testing OR Cardiopulmonary exercise test OR Cardiopulmonary exercise testing OR Peak oxygen uptake OR Maximal oxygen consumption OR Exercise tolerance OR Exercise capacity AND Heart rate OR Heart rates OR Pulse rate OR Pulse rates OR Heart rate control OR Cardiac chronotropic OR Predictive value test AND Predictive equations". Resultados: De um total de 1664 artigos, apenas 4 foram incluídos. Todos os estudos compararam os valores medidos de FCmáx com os estimados pela equação "220 - idade", 3 utilizaram a fórmula "208 - (0,7 x idade)" e apenas 1 a equação "223 - (1,44 x idade)". Embora todos demonstraram que a equação "220 - idade" superestima a FCmáx, a fórmula "208 - (0,7 x idade") subestimou (2 artigos) e superestimou (1 estudo) os resultados medidos, enquanto a equação "213 - (1,44 x idade) também não foi adequada. Conclusão: O uso de equações preditivas de FCmáx em crianças e adolescentes atletas não parece indicado. Recomenda-se cuidadosamente a utilização de pontos de coorte para essas estimativas.

Resumen Introducción: La frecuencia cardiaca máxima (FCmáx) se denomina el mayor valor de FC alcanzado durante un esfuerzo físico cercano al agotamiento. Objetivo: Evaluar la aplicabilidad de las ecuaciones predictivas de FCmáx durante las pruebas de ejercicio en niños y adolescentes atletas. Métodos: Se trata de una revisión sistemática, a través del Scopus, Pubmed, Lilacs, Scielo y PEDro. Se incluyeron estudios que compararon la FCmáx medida y la estimada por ecuaciones predictivas durante pruebas de ejercicio en niños y adolescentes atletas. Se utilizó la siguiente estrategia de búsqueda: "Exercise test OR Exercise testing OR Cardiopulmonary exercise test OR Cardiopulmonary exercise testing OR Peak oxygen uptake OR Maximal oxygen consumption OR Exercise tolerance OR Exercise capacity AND Heart rate OR Heart rates OR Pulse rate OR Pulse rates OR Heart rate control OR Cardiac chronotropic OR Predictive value test AND Predictive equations". Resultados: De un total de 1664 artículos, sólo 4 fueron incluidos. Todos los estudios compararon los valores medidos de FCmáx con los estimados por la ecuación "220 - edad", 3 utilizaron la fórmula "208 - (0,7 x edad)" y sólo 1 la ecuación "223 - (1,44 x edad". Aunque todos demostraron que la ecuación "220 - edad" sobreestima la FCmáx, la fórmula "208 - (0,7 x edad") subestimó (2 artículos) y sobreestimó (1 estudio) los resultados medidos, mientras que la ecuación "213 - (1,44 x edad) tampoco fue adecuada. Conclusión: El uso de ecuaciones predictivas de FCmáx en niños y adolescentes atletas no parece indicado. Se recomienda cuidadosamente el uso de puntos de cohorte para estas estimaciones.