2006 OPEN FORUM Abstracts
An Evaluation of Twenty-four Hour Noninvasive Ventilation By End-Tidal C02 Monitoring For Neuromuscular Patients with Chronic Respiratory Insufficiency
Louis J. Boitano MSc, RRT, Joshua O. Benditt M.D.,
Departments of Respiratory Care, and Pulmonary and Critical Care Medicine,
University of Washington Medical Center, Seattle, WA
Open circuit mouthpiece ventilation (MPV) is a form of noninvasive ventilation that can be used for portable daytime ventilatory support. MPV can be combined with nocturnal bilevel pressure ventilation to provide 24 hour noninvasive ventilatory support. While a number of retrospective studies have evaluated the effectiveness of daytime MPV and nocturnal bilevel pressure ventilation by evaluating morbidity, survival and quality of life, none have evaluated the effectiveness of ongoing 24 hour noninvasive ventilation by serial end-tidal carbon dioxide or arterial carbon dioxide testing. We hypothesized that serial outpatient clinical end-tidal C02 measures could be used to noninvasively monitor the efficiency of MPV support combined with nocturnal noninvasive bilevel pressure ventilation. A retrospective review study was done on a group of 24 neuromuscular patients with diagnoses including Duchenne and Becker muscular dystrophy, myotonic dystrophy, spinal muscular atrophy, post-polio syndrome and amyotrophic lateral sclerosis who were clinically followed after initiating MPV for portable daytime support. All patients were supported by nocturnal noninvasive bilevel pressure ventilation prior to initiating MPV and were started on MPV because of either developing daytime hypercarbia or shortness of breath. The study duration included patients who were followed from at least six months up to more than six years. End-tidal carbon dioxide measures were done by side stream nasal cannula sampling at each outpatient clinic visit for each of the study patients. Almost all patients who were hypercarbic on initiation of MPV showed a significant decrease in end-tidal C02 after starting MPV (P<0.0001). Patients who were dyspneic but normocarbic on initiation of MPV maintained a C02 within normal range with progressive respiratory insufficiency over time. Serial end-tidal C02 testing may be used as a means of monitoring the ongoing noninvasive respiratory support of neuromuscular patients with chronic respiratory insufficiency.
Serial end-tidal C02 with 24 hour noninvasive ventilation over time