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

Reimberg MM; Ritti-Dias R; Selman JP; Scalco RS; Wandalsen GF; Solé D; Hulzebos HJ; Takken T; Corso SD;
Lanza FC;

Pediatric pulmonology [Pediatr Pulmonol] 2021 Sep 27. Date of Electronic Publication: 2021 Sep 27.

Purpose: Whether modified shuttle teste (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: cross sectional study, volunteers with asthma (6 to 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 (VO 2 , VCO 2 , and VE) and heart rate (HR) were the outcomes, and continuously assessed in both tests.
Results: 47 volunteers were included, normal lung function FEV1/FVC 88.6 (7.7). VO 2peak was higher at MST (2.0 ± 0.6 L/min) compared to CPET (1.6 ± 0.5 L/min), p< 0.001. Similar to VE at MST (50 ± 16 L/min) vs at CPET (40 ± 13 L/min), and VCO 2 , at MST (2.1 ± 0.8 L/min) vs CPET (1.7 ± 0.6 L/min), p < 0.001. HR was also higher at MST (94 ± 6%pred) vs CPET (87 ± 8%pred), p=0.002. VO 2peak in MST correlated to the CPET (r = 0.78, p < 0.001). The ICC of VO 2peak between tests was 0.73 (0.06 – 0.89), p<0.001, and VO2peak Bland-Altman analysis showed bias of 0.46L/min.
Conclusion: the MST showed maximal physiologic response in children and adolescents with asthma. It is valid test, and can be used as an alternative to evaluate exercise capacity.