Cochlear implantation surgery with conscious sedation in the very elderly: a feasibility study comparing cochlear implant outcomes in general anaesthesia (GA) and local anaesthesia (LA) cohorts

Background: To characterize outcomes of very elderly patients who have had cochlear implant (CI) surgery under awake conditions with local anaesthesia (LA)/conscious sedation with patients who underwent CI surgery under general anaesthesia (GA), as a preliminary feasibility study prior to a more detailed investigation. Methods: Sixteen patients 80+ years who underwent CI under awake LA conditions were compared to 28 age-matched patients implanted under GA over an empirically chosen 2-year period 2018–2020. Results: Preoperative patient characteristics and post-operative surgical experiences were similar in both GA and LA groups. Post op confusion risk increases by 1.042-fold [odds ratio (OR) =1.042; 95% confidence interval (95% CI): 1.1 to 131.2; P=0.042] for every 1-minute increase in duration of anaesthetic. As the number of comorbidities increases there was a trend for an increased risk of cognitive impairment by almost two and half times (OR =2.4; 95% CI: 0.9 to 6.1; P=0.065). In this study GA was more likely to be associated with post operative confusion (P=0.013). Age or gender did not have a significant effect on post op confusion. Conclusions: Surgery duration and patient comorbidities has a greater effect on post-operative confusion than type of anaesthetic delivered by GA or LA. Age was not a significant factor in determining post-operative confusion. There is a high degree of variability in our study cohort as such, the results need to be interpreted with some caution.