1226 Two cases of central sleep apnea in patients on intrathecal baclofen (ITB)

Abstract

Introduction: Central sleep apnea (CSA) has been reported in association with baclofen, a GABAB receptor agonist. Few studies have described CSA in patients using intrathecal baclofen (ITB). Here we describe two such patients seen in sleep clinic. Report of Case: A 32-year-old male was referred for snoring and gasping sensations. History was significant for treated childhood astrocytoma and strokes resulting in left hemiparesis, spasticity and functional deficits. He had been on ITB for nine years prior to presentation. Apnea-hypopnea index (AHI) was 154.3 events/hour, including 332 central apneas. CPAP failed to resolve central apneas, but adaptive servo-ventilation (ASV) at 9 cm H2O resolved both obstructive and central apneas. A 40-year-old male with spastic tetraplegia from a traumatic brain injury (TBI) in 1995 was seen for unrefreshing sleep and excessive daytime sleepiness. He had been using an ITB for 10 years prior to presentation. A polysomnography (PSG) showed an overall AHI of 42, predominantly from 238 central apneas, which improved after treatment with ASV. Conclusion(s): CSA has previously been described in patients on baclofen therapy for alcohol withdrawal, but few studies have described CSA in patients with ITB for spasticity. Baclofen decreases minute ventilation in animals, but the mechanism by which it does so is unclear at this time. A pilot study revealed bolus administration of ITB can worsen pre-existing sleep apnea, whereas a continuous infusion did not significantly affect previous sleep disordered breathing. It may be important to perform PSG in patients prior to ITB pump placement. Another study demonstrated changes in sleep architecture and minor decreases in mean oxygen saturations following administration of oral baclofen, but limited effects on sleep-disordered breathing (SDB). It is possible that TBI and/or stroke may have contributed to the SDB observed in our patients. Our patients experienced improvement in CSA following ASV.