Functional capacity and quality of life in children and adolescents with sickle cell anemia.

OBJECTIVE: To evaluate the functional and exercise capacity, lung function, quality of life of children and adolescents with sickle cell anemia (SCA HbSS) and to test the reproducibility of functional capacity tests in this population. METHOD: Cross-sectional study with volunteers with SCA Hb-SS (SCAG), aged 6-18 years matched in age and gender to the control group (CG) with healthy individuals. Spirometry, 5-repetition sit-to-stand test (5STS-test), modified shuttle test (MST), and Pediatric Quality of Life Questionnaire (PedsQL) were performed. The reproducibility of 5STS-test and MST was evaluated: RESULTS: Forty eight volunteers of SCAG and 48 of CG were evaluated. Lung function of SCAG (FVC: 92 ± 15% pred.; FEV1 /FVC: 84 ± 8% pred.) was worse than the CG (104 ± 15% pred.; FEV1 /FVC: 90 ± 6% pred.) p < 0.05. SCAG had worse functional capacity registered by distance walked: 576 m (515-672 m) and 5STS-test: 8 s (7.4-8.9 s) compared with the CG who showed distance walked: 1010 m (887-1219 m) and 5STS-test: 7 s (7.0-8.1 s), p < 0.001. SCAG had worse quality of life compared to CG, p < 0.05. The reproducibility of MST (ICC 0.99 (0.98-0.99 IC-95%)) and 5STS-test (ICC 0.80 (0.69-0.88) was considered good, p < 0.001. CONCLUSION: Children and adolescents with sickle cell anemia presented worse capacity to walk or run, and to perform sit-to-stand test when compared with their control peers. Additionally, they have poorer quality of life. The MST and 5STS-test showed good reproducibility to be applied in pediatric individuals with SCA.

Is the modified shuttle test a maximal effort test in children and adolescents with asthma?

PURPOSE: Whether the modified shuttle test (MST) achieves maximal effort in children and adolescents with asthma is unclear. The aim was to compare the physiological responses of MST to the cardiopulmonary exercise test (CPET) in pediatric patients with asthma, to observe its convergent validity. PATIENTS AND METHODS: A cross-sectional study with volunteers with asthma (6-17 years of age) under regular treatment. The MST is an external-paced test, and the participants were allowed to walk/run. CPET was performed on a cycle ergometer to compare with MST. Gas exchange (VO2 , VCO2 , and VE) and heart rate (HR) were the outcomes and were continuously assessed in both tests. RESULTS: Forty-seven volunteers were included, normal lung function expiratory forced volume at 1st second/forced vital capacity (FEV1 /FVC) 88.6 (7.7). VO2peak was higher at MST (2.0 ± 0.6 L/min) compared to CPET (1.6 ± 0.5 L/min), p < 0.001. Similar results was observed to VE at MST (50 ± 16 L/min) versus VE at CPET (40 ± 13 L/min), and to VCO2 at MST (2.1 ± 0.8 L/min) versus VCO2 at CPET (1.7 ± 0.6 L/min), p < 0.001. HR was also higher at MST (94 ± 6%pred) versus CPET (87 ± 8%pred), p = 0.002. VO2peak in MST correlated to the CPET (r = 0.78, p < 0.001). The ICC of VO2peak between tests was 0.73 (0.06-0.89), p < 0.001, and VO2peak Bland-Altman analysis showed a bias of 0.46 L/min. CONCLUSION: The MST showed a maximal physiologic response in children and adolescents with asthma. It is a valid test and can be used as an alternative to evaluating exercise capacity.

Heart rate recovery in asthmastic children and adolescents after clinical field test.

BACKGROUND: Inflammation caused by chronic lung disease in childhood may lead to delayed heart rate recovery (HRR) however, there is lack of evidence on HRR in this population. The aim was to assess HRR after functional capacity testing in asthmatic children and adolescents and to compare with severity and disease control. METHOD: This was a study secondary to a randomized control trial. The modified shuttle test (MST) was performed to assess functional capacity and HRR. This is an externally cadenced test in which the distance walked is the outcome. HRR was assessed after MST and was defined as HR at exercise peak minus HR in the second minute after the end of exercise. Asthma control was assessed by the Asthma Control Test (ACT). Data normality was tested by Shapiro Wilk and the comparison between groups was made by Student's t test or Mann Whitney test for numerical variables, and by Chi-square test for categorical variables. Statistical significance was considered when p < 0.05. SPSS version 20 was used in the analyzes. RESULTS: The sample included 77 patients diagnosed with asthma (asthma group - AG) who were regularly treated for asthma. Control group (CG) consisted of 44 volunteers considered healthy, matched in age and gender to AG. The median age of CG was 12 (10-14) years and in AG 11 (9-13 years) being classified as mild to moderate asthmatic, and 57% of the sample had controlled asthma by ACT. Distance walked in the CG was 952 ± 286 m and AG 799 ± 313 m, p = 0.001. HRR was more efficient in CG (79 ± 15 bpm) compared to AG (69 ± 12 bpm), p = 0.001. The mild (69 ± 12 beats) and severe (72 ± 15 beats) AG presented worse HRR compared to control group (79 ± 15 bpm), p < 0.05. CONCLUSIONS: Asthmatic children and adolescents have delayed HRR after modified Shuttle test compared to their peers, suggesting that asthma leads to autonomic nervous system imbalance. TRIAL REGISTRATION: Registered in Clinical Trials under number NCT02383069 and approved by the Universidade Nove de Julho - UNINOVE Research Ethics Committee, protocol number 738192/2014.

Validation of the Modified Shuttle Test to Predict Peak Oxygen Uptake in Youth Asthma Patients Under Regular Treatment.

Background: Oxygen uptake (VO2) evaluations by cardiopulmonary exercise test is expensive and time-consuming. Estimating VO2 based on a field test would be an alternative. Objective: To develop and validate an equation to predict VO2peak based on the modified shuttle test (MST). Methods: Cross sectional study, with 97 children and adolescents with asthma. Participants were divided in two groups: the equation group (EG), to construct the equation model of VO2peak, and the cross-validation group (VG). Each subject performed the MST twice using a portable gas analyzer. The peak VO2peak during MST was used in the equation model. The patients' height, weight, gender, and distance walked (DW) during MST were tested as independent variables. Results: The final model [-0.457 + (gender × 0.139) + (weight × 0.025) + (DW × 0.002)] explained 87% of VO2peak variation. The VO2peak predicted was similar to VO2peak measured by gas analyzer (1.9 ± 0.5 L/min and 2.0 ± 0.5 L/min, respectively) (p = 0.67), and presented significant ICC 0.91 (IC95% 0.77 to 0.96); p < 0.001. The Bland-Altman analysis showed low bias (-0.15 L/min) and limits of agreement (-0.65 to 0.35 L/min). There was no difference in DW between EG (760 ± 209 m) and VG (731 ± 180 m), p = 0.51. Conclusion: The developed equation adequately predicts VO2peak in pediatric patients with asthma.