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
