Exertional Desaturation and Ambulatory Oxygen Therapy Requirements in People with Idiopathic Pulmonary Fibrosis. A Retrospective Study

Abstract

Introduction. Exertional desaturation (ED) is common in advanced idiopathic pulmonary fibrosis (IPF) stages. Ambulatory O2 therapy could increase physical activity by preventing ED in people with IPF. Objective. This study aimed to assess ED and ambulatory O2 requirements in people with IPF using a protocol that involved up to four 6-minute walking tests (6MWT). Method. An observational study of a dynamic retrospective cohort from a high-complexity hospital was conducted. The ambulatory O2 requirement assessment protocol involves performing up to four 6MWT depending on ED. All participants performed the baseline test (no additional O2). If ED (SpO2 < 90%) was observed, up to three additional 6MWTs were performed with two, four, and six O2 liters/minute until ED was avoided. Results. Twenty-eight patients (16 female; mean age 73 years) were referred for assessment of ambulatory O2 requirements. Twenty-three (82%) had ED during baseline 6MWT. Twenty-two patients performed the 6MWT with two liters/minute of O2, ten performed a third 6MWT with four liters/minute of O2, and seven with six liters/minute of O2. The six participants who performed all four 6MWTs significantly increased their walking distance by 56.33 meters (SD 36.45) compared to the baseline (p = 0.001). Four of the seven patients (57.14%) who performed the last 6MWT had ED despite O2 supplementation. Conclusion. The prevalence of ED during baseline 6MWT was high. Some participants even experienced ED with six liters/minute of supplemental O2. Despite this, walking distance increased more than the learning effect.