P109 Bulbar-MND meets NIV eligibility sooner using pragmatic nocturnal pulse oximetry

Abstract Background and objective Pulmonary function measures are commonly used to determine timing of NIV initiation in people with motor neuron disease (pwMND). However, in those with bulbar-onset disease, testing may be difficult to perform and result in spurious findings. This study was undertaken to determine whether nocturnal pulse oximetry (NPO) provides earlier insights into abnormalities in oxygenation even in the absence of symptoms. Methods We conducted a retrospective analysis of 93 pwMND who underwent three consecutive nights of NPO. The presence of orthopnoea and proportion of pwMND meeting criteria to initiate NIV was compared in bulbar and non-bulbar groups. Data were analysed using independent t-tests and chi-square tests. Results The presence of orthopnoea and proportion fulfilling criteria to initiate NIV were similar between bulbar and non-bulbar groups (24% vs. 20%, p=0.62; and 76% vs. 67%, p=0.40, respectively). People with bulbar-onset MND were older and underwent initial oximetry earlier in their disease trajectory following MND symptom onset than those with non-bulbar MND (67 ± 10.5 vs 61 ± 11.9 years old, p=0.02 and 17.5 (11–24.75) vs. 31.0 (18–63.5) months, p=0.005, respectively). Conclusion People with bulbar-onset MND were assessed with NPO an average of 13.5 months sooner and met criteria for NIV at the same rate as non-bulbar MND. Absence of orthopnoea is a poor indicator of respiratory function in bulbar-onset and non-bulbar MND. Given the difficulties performing lung function, early and regular NPO assessment of bulbar MND patients is warranted, even in in the absence of symptoms.