Effects of High-Flow Nasal Cannula on Exercise Outcomes in Lung Transplant Candidates: A Pilot Study

Overview

The study evaluated patients on the national lung transplant waiting list. It was pioneering in assessing high-complexity patients with severe pulmonary diseases subjected to a cardiopulmonary rehabilitation protocol using a treadmill. The main findings indicate that the distance covered in the six-minute walk test was greater when using the high-flow nasal cannula supplementation. The improvement in exercise performance in this group is associated with a reduction in arterial carbon dioxide, optimization of hydrogen potential, and a decrease in dynamic hyperinflation, leading to fewer symptoms of dyspnea.

Introduction: Pulmonary diseases have a significant global prevalence, and lung transplantation is indicated for advanced cases. Rehabilitation is essential for patients on the waiting list and requires ventilatory devices for symptom control during exertion. The high-flow nasal cannula is a promising alternative, but its effects on exercise outcomes are uncertain. Objectives: To assess the effects of high-flow nasal cannula on the outcomes of the six-minute walk test. Method: A randomized crossover clinical trial evaluated ten volunteers listed on the national lung transplant waiting list. Three functional tests were performed: the six-minute walk test, incremental lower limb test with arterial blood gas analysis, and lower limb endurance test with inspiratory capacity measurement. Each test was conducted on different days with different devices: high-flow nasal cannula and conventional oxygen therapy, totaling six test days. The inspired oxygen fraction was titrated to maintain normoxia between 90% to 96% and was kept constant for both interfaces.