O054 Targeted ansa cervicalis nerve stimulation restores airflow to airway narrowing in obstructive sleep apnoea during propofol anaesthesia

Abstract Introduction The pathophysiology of upper airway collapse in obstructive sleep apnoea (OSA) is multifactorial. Earlier animal and recent human data indicate that ansa cervicalis nerve stimulation may improve pharyngeal airflow via increased airway traction. We investigated a novel, targeted, neurostimulation approach of ansa cervicalis to improve upper airway function in people with OSA. Methods Participants with OSA (AHI>15 events/h) were administered drug-induced sleep endoscopy with propofol and equipped with a nasal mask connected to a pneumotachograph to measure airflow and a modified continuous positive airway pressure (CPAP) device. Ultrasound was used to identify and guide percutaneous insertion of a temporary multi-electrode array to target the ansa cervicalis nerve. Therapeutic CPAP was reduced to induce transient airflow limitation. Ansa cervicalis stimulation was applied at varying stimulus amplitudes and electrode configurations until optimised. Changes in peak inspiratory airflow (PIF) from therapeutic CPAP levels to transient CPAP reductions were compared without and with optimal ansa cervicalis stimulation. Results 13 (3 female) predominantly non-obese (BMI=28±4Kg/m²) participants with OSA (AHI=38±16 events/h) aged 51±14 years (mean±SD) were studied. Preliminary findings in 10 participants show that 9/10 had increased PIF with 3.2±1.2mA stimulation. PIF at therapeutic CPAP was 0.37±0.13L/s. During CPAP reductions, PIF decreased to 0.18±0.13L/s (p<0.05) but returned to therapeutic CPAP levels (0.39±0.19L/s) during ansa cervicalis stimulation. Conclusion A novel, minimally-invasive, percutaneous stimulation approach to target the ansa cervicalis can markedly improve upper airway function during transient airway narrowing/closure in people with OSA during drug-induced sleep endoscopy.