Hao Wu,1,* Shunping Tian,1,* Hongxia Ma,2,* Wei Zhou,1 Shantian Feng,1 Lijun Meng,3 Jinlei Ou,3 Fei Xu,1 Zhuan Zhang1 

1Department of Anesthesiology, The Affiliated Hospital of Yangzhou University, Yangzhou, 225012, People’s Republic of China; 2Department of Anesthesiology, The Second People’s Hospital of Lianyungang, Lianyungang, 222023, People’s Republic of China; 3Intensive Care Unit, The Affiliated Hospital of Yangzhou University, Yangzhou, 225012, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Zhuan Zhang, Department of Anesthesiology, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu, 225012, People’s Republic of China, Tel +86 15062791355, Email zhangzhuancg@163.com

Purpose: Low density of electroencephalogram alpha band power was reported to be associated with perioperative cognitive dysfunction. Few studies have conducted to explore the effects of remimazolam on intraoperative frontal alpha band power spectrum density in older adults. Here, we aimed to explore the impact of remimazolam on intraoperative frontal brain wave alpha band activity and postoperative cognitive function in older adults undergoing lower extremity fractures surgeries.
Methods: Patients undergoing elective general anesthesia for lower extremity fracture surgery were randomly allocated to remimazolam group (Group R) and midazolam group (Group M). Group R was induced with remimazolam bolus 0.1 mg/kg followed by a maintenance dose of 0.1 mg·kg− 1·h− 1 for general anesthesia. Group M was induced with midazolam 0.05 mg/kg followed by normal saline maintenance of 0.1 mL·kg− 1·h− 1. The rest anesthesia protocol was the same for both groups. Electroencephalogram data was recorded before anesthesia induction till the end of surgery. Cognitive function was assessed preoperatively, and at the first, third, fifth, and seventh day postoperatively.
Results: Compared with Group M, Group R had significantly higher intraoperative power spectral density of the frontal alpha band (P < 0.001), and significantly lower incidence of postoperative cognitive dysfunction at T8 and T9 (P = 0.031 and P = 0.017, respectively).
Conclusion: Remimazolam can increase frontal brain wave alpha band power spectrum density and improve postoperative cognitive function in older adults undergoing lower extremity fractures surgeries.

Keywords: brain waves, alpha band, benzodiazepines, remimazolam, cognitive dysfunction, elderly, neuropsychological tests