Introduction: The six-minute walk test (6MWT) is a valid and reliable measure of exercise capacity for people with chronic lung disease. Nevertheless, there are no recommendations for Children with Medical Complexity and Chronic Lung Diseases (CMC-CLD). Our aims were to determine the performance, safety, and reliability of the 6MWT in this population.

Methods: Cross-sectional study, 17 children were included at Josefina Martínez Hospital with CMC-CLD and technological aids who performed a modified 6MWT between 2017-2021. The 6MWT modifications to ATS statements were: 1. Continuous encouragement, 2. Two investigators walked with the patient to carry their mechanical ventilator and oxygen device. 3. Use of a panel where the child put velcro figures, as a ludic strategy. Statistical analyses included descriptive statistics. Test-retest reliability was measured with an intraclass correlation coefficient (ICC). This study counts on the South-east metropolitan health service ethics committee's approval.

Results: 12/17 were males. fifteen were tracheostomized patients, and 15 were users of mechanical ventilation. The main diagnoses were bronchopulmonary dysplasia(35%)and Post-infectious obliterans bronchiolitis(24%). The mean of 6MWT distance was 349m ±118.14, with a 63%(51-73%) of predicted values. Ventilated patients walked less distance than nonventilated children (p=0.006). Only one patient with diffusion disorder had desaturation to 84%, but he recovered at the first-minute post-test. The ICC was 0.989 (CI 95%, 0.97 to 0.99) indicating excellent reliability. 

Conclusions: CMC-CLD have a decreased functional exercise capacity and Modified 6MWT was safe and reliable for this population.