The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts


Kim Robbins1, Gary R. Lowe1, Ariel Berlinski2; 1Respiratory Care Services, Arkansas ChildrenÂ’s Hospital, Little Rock, AR; 2Dept. of Pediatrics, Pulmonary Medicine Section, University of Arkansas for Medical Sciences, Little Rock, AR

Introduction: The 6-Minute Walk Test (6MWT) is a reliable and reproducible study for suboptimal exercise in pulmonary patients with moderate to severe impairment. This report relates our experience with a severely impaired adolescent in assessing supplemental O2 needs for activities of daily living (ADL). Case Summary: A 15 y/o female presented with a complaint of severe dyspnea on exertion which progressively worsened over the last three years. She had been diagnosed with nasopharyngeal rhabdomyosarcoma at age 8. She was treated with radiation and chemotherapy and was in remission since age 9. The patient was admitted for evaluation of dyspnea. Possible differential diagnoses included restrictive lung disease, V/Q mismatch, pulmonary hypertension, and silent aspiration. Previous spirometry showed severe restrictive lung disease (FVC=36%, FEV1=37%, FEV1/FVC=91%). Serial chest CTs had been performed and the most recent showed progressive, extensive cystic bronchiectatic changes. A swallow study showed mild dysphagia. The echocardiogram was consistent with pulmonary hypertension. V/Q scan showed right upper lobe was non-functioning. Her SpO2 at rest was 99 -100%. The patient performed 3 different 6MWT. The initial study (day 2, without supplemental O2) showed desaturation with lowest SpO2 of 83%. A treadmill study (day 7) was performed for titration of supplemental O2 and revealed a 2 L/min O2 requirement. A repeat 6MWT (day 9, on 2 L/min O2), performed while pulling a portable O2 concentrator (POC) (wt. = 4.5 kg) showed desaturation with lowest SpO2 of 82%. A lighter portable liquid O2 system (wt. = 2.7 kg) was substituted and the 6MWT was repeated revealing a 2.5 L/min requirement. She was discharged the next day with supplemental O2 at 2.5 L/min for normal ADL. Discussion: This study illustrates three important points. First, O2 titration needs to be done under real life conditions. We found that the weight of the POC increased her workload, thus increasing her O2 requirement. Second, this study relied heavily on collecting oximetry data during all phases of the study and quantified physiologic needs. Although ATS guidelines state that pulse oximetry is optional and that SpO2 should not be used for constant monitoring during exercise, it was very informative in this case. Third, this case underscores the importance of evaluating for desaturation during exercise in patients presenting with dyspnea. Sponsored Research - None