Discussion
delirium, bradycardia, sleep disorders, sleep disturbance, anxiety, pain, hypotension
REGRESSION, ADVERSE EFFECTS, RESPIRATORY DEPRESSION
The present study demonstrated that intraoperative remimazolam sedation (kept at BIS 70–80), compared with those mainly treated with dexmedetomidine, did not significantly improve postoperative sleep quality in elderly patients receiving total joint arthroplasty under neuraxial anaesthesia. However, remimazolam is proved to be effective and safe for moderate sedation in elderly during reginal anaesthesia.Nowadays, sleep disturbance after surgery has become a major concern especially in elderly patients. In this study, very poor or poor sleep quality happened in about half of patients at surgery night and its severity gradually alleviated during the following two nights, which was in line other studies [In the present study, remimazolam was titrated to maintain sedation depth at BIS 70–80. This is based on the result of previous study in which intraoperative midazolam with BIS of 75–80 improved postoperative sleep quality [The effect of remimazolam on sleep quality might be underestimated by the relatively small sample size of our study. Beyond anxiety, sleep disturbance arises from multiple etiologies including pain intensity, environmental noise, and procedures of medical therapy [Sedation strategy in routine group is based on daily clinical practice in two participating centres because of the following concerns. First, sedation at the discrete of patient’s demand and anaesthesiologist’s advice is the most common approach in most centres. The data originated from routine group are close to real-world practice and this facilitates the generalization of our result. Second, most sedatives were given in terms of clinical experience but not BIS-guided sedation in daily practice. Thus, BIS readings in routine group were masked to attending anaesthesiologists, which helps to alleviate the influence of BIS monitoring on daily practice. Third, previous evidence reported that intraoperative dexmedetomidine at 0.2–0.4 μg/kg/h might decrease the incidence of severe sleep disturbance at surgery night [We noticed that patients in routine group have lighter sedation depth in comparison with remimazolam group. We took two steps to evaluate the effect of BIS value on outcome. Multivariable linear regression was firstly administrated to adjust TWA BIS and other confounders. Second, a post-hoc analysis was employed to compare outcomes in patients with remimazolam and dexmedetomidine after exclusion of 9 patients without dexmedetomidine in routine group. The result was consistent with intention-to-treat analysis. Based on clinical experience, anaesthesiologists are prone to maintain lighter sedation in avoidance of adverse effects such hypotension and bradycardia by dexmedetomidine. In this study, we also observed slightly higher incidence of hypotension in routine care group but without statistical significance. However, the effect of sedation depth on patient’s prognosis is uncertain till now. In patients undergoing hip surgery, BIS-guided propofol light sedation (BIS > 80 versus deep BIS < 50) was associated with 50% reduction in postoperative delirium and 1 year mortality [To date, few studies have evaluated the effectiveness and safety of remimazolam infusion for sedation in elderly patients during spinal anaesthesia. Our study reported that a loading dose followed by continuous infusion of remimazolam could be safely and effectively used for intraoperative targeted sedation without increasing risks of adverse outcomes such as hypotension and respiratory depression.Preoperative sleep disturbance is associated with postoperative sleep and pain intensity [Our study had several limitations. First, architecture of sleep was monitored by RCSQ but not polysomnography. It is true that polysomnography represents a gold-standard tool for evaluation of sleep disorders [In conclusion, for elderly patients undergoing total joint arthroplasty under neuraxial anaesthesia, intraoperative remimazolam can be safely and effectively used for sedation, but its effect on postoperative sleep quality is still uncertain.