@article {Domnik4404, author = {Nicolle J. Domnik and Robin Scheeren and Sarah Taylor and Helen Driver and Sophie Crinion and J Alberto Neder and Denis O{\textquoteright}Donnell}, title = {Impact of bronchodilator therapy on diaphragmatic function in sleep in COPD}, volume = {56}, number = {suppl 64}, elocation-id = {4404}, year = {2020}, doi = {10.1183/13993003.congress-2020.4404}, publisher = {European Respiratory Society}, abstract = {The impact of bronchodilation (BD) on diaphragm activation (electromyography, EMGdi) and force generation (transdiaphragmatic pressure, Pdi) during sleep in Chronic Obstructive Pulmonary Disease (COPD) is unknown. We examined the effect of nocturnal BD on inspiratory neural drive (IND) in supine wakefulness (W) and sleep (non-rapid eye movement stage 2, N2) at equivalent time-points overnight.20 patients with COPD (FRC 147{\textpm}32\%pred; post-BD FEV1 56{\textpm}16\%pred) completed a double-blinded, placebo-controlled crossover study with two 2wk treatment arms (BD: aclidinium bromide/formoterol fumarate 400/12mcg, or Placebo, PL), polysomnography, and measurement of IND (EMGdi,\%max) and Pdi(\%max) during stable breathing in W at 2, 6 \& 10h post-dose and in N2 directly before W testing at 6 \& 10h post-dose.BD (vs PL) improved IC and FEV1 by up to 334{\textpm}310mL and 184{\textpm}170mL (p\<0.05). In W, BD reduced EMGdi (-21\%) and Pdi (-20\%;p\<0.05) for 2h post-dose. At 6h post-dose, BD decreased EMGdi (-35\%,p\<0.05) in N2. BD did not alter neuromuscular efficiency (EMGdi/Pdi) in W or N2. Within each treatment, sleep decreased EMGdi vs W up to 35\% (p\<0.05) but didn{\textquoteright}t alter Pdi, such that EMGdi/Pdi decreased from W to N2 (p\<0.05).Improved IND and respiratory mechanics (Pdi) after BD in wakefulness were associated with improvements in IND after BD during sleep. Neuromuscular efficiency was unchanged by BD despite the marked decrease in IND between W and N2 in both groups.FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 4404.This abstract was presented at the 2020 ERS International Congress, in session {\textquotedblleft}Respiratory viruses in the "pre COVID-19" era{\textquotedblright}.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/56/suppl_64/4404}, eprint = {https://erj.ersjournals.com/content}, journal = {European Respiratory Journal} }