Efficacy Of Dexmedetomidine In Preventing Development Of Postoperative Delirium In Patients With Schizophrenia

Objective: To evaluate the efficacy of dexmedetomidine in preventing the development of postoperative delirium in the patients with schizophrenia.Methods: This study was approved by the Ethics and Research Committee of our hospital. Written informed consent was obtained from all the participants in the study. Ninety patients with schizophrenia of both sexes, of ASA physical statusⅠorⅡ, aged 20-64 year, weighing 45-90 kg, scheduled for elective emergency operation under general anesthesia, were randomly divided into 3 groups(n=30 each) using a random number table: high-dose dexmedetomidine group(group HD), low-dose dexmedetomidine group(group LD) and control group(group C). In HD and LD groups, dexmedetomidine 1.0 and 0.5 μg/kg were injected intravenously, respectively, within 10 min prior to induction of general anesthesia, followed by continuous infusion at 0.4 and 0.2 μg·kg-1·h-1 until the end of operation, respectively. The equal volume of sodium chloride injection was given in group C.The patients underwent fasting and water deprivation before operation and were unpremedicated. After admission to the operating room, lactated Ringer’s solution 6-8 ml/kg was infused intravenously. Blood pressure(BP), pulse oxygen saturation(Sp O2), heart rate(HR), electrocardiogram(ECG), and body temperature(T) were monitored routinely. BIS value was monitored using an A-2000 xp monitor. Anesthesia was induced with iv injection of midazolam 1-2mg, fentanyl 3-5μg/kg, propofol 1.5-2.5mg/kg and cis atracur-ium 0.15mg/kg. The patients were endotracheally intubated and mechanically ventilated(oxygen flow rate 1-2L/min, RR 10-15 bpm, VT 8-10 ml/kg, I:E 1:2). PETCO2 was maintained at 35-40 mm Hg(1mm Hg = 0.133 k Pa). After induction of anesthesia, the radial artery was cannulated for blood pressure monitoring. Anesthesia was maintained with continuous iv injection of propofol 2-6mg·kg-1·h-1, remifentanil 0.1-0.3μg·kg-1·h-1, inhalation of sevoflurane(end-tidal concentration 1-3 %), and iv infusion of cisatracurium 0.1mg·kg-1·h-1 using combined intravenous-inhalational anesthesia. The concentrations of propofol, sevoflurane and remifentanil were adjusted to maintain BIS value at 40-55. The vasoactive drugs were used when necessary. Patient-controlled intravenous analgesia(PCIA) was used within 48 h after operation. The PCIA contained sufentanil 2μg/kg, dezocine 0.3mg/kg and azasetron 20 mg(in 200 ml of normal saline) with background infusion 2 ml/h, bolus dose 1 ml and lockout interval 15 min. VAS score was maintained ≤ 3 after operation. The operation time and duration for anesthesia were recorded. The end-tidal concentration of sevoflurane(ETsev) was recorded every 30 min after intubation. The sleep quality was evaluated and recorded at 6h, 1d, 2d and 3d after operation. The development of delirium was recorded during emergency from anesthesia and within 3 d after operation.Results:1 There was no significant difference in age, gender, body weight, ASA physical status, BP and HR between the three groups.2 Compared with group C, the sleep quality score was significantly decreased after operation in group HD, and the sleep quality score was significantly decreased at 6 h after operation in group LD.3 Intraoperative BP and HR were relatively stable in the three groups. Compared with group C, ETsev was significantly decreased in HD and LD groups.4 Compared with group C, the incidence of delirium during emergency from anesthesia and within 1-3d after operation was significantly decreased in HD group, and the incidence of delirium during emergency from anesthesia was significantly decreased, and no significant change was found in the incidence of delirium within 1-3d after operation in group LD. The incidence of delirium within 1-3d after operation was significantly lower in group HD than in group LD.5 There was no significant difference in the development of side effects such as bradycardia, hypotension and hyoxemia between C, HD and LD groups.Conclusions: Dexmedetomidine can reduce the development of post-operative delirium in the patients with schizophrenia.