Effects of different sedation depths of propofol on postoperative delirium in patients undergoing cardiac valve replacement under cardiopulmonary bypass: the relationship with regional cerebral oxygen saturation

Abstract

Objective To evaluate the effects of different sedation depths of propofol on postoperative delirium in patients undergoing cardiac valve replacement under cardiopulmonary bypass(CPB)and the relationship with regional cerebral oxygen saturation(rSO2). Methods Forty American Society of Anesthesiologists physical status Ⅲ or Ⅳ patients of both sexes, aged 26-64 yr, with body mass index of 17-25 kg/m2, scheduled for elective aortic valve replacement with CPB, were divided into A and B groups(n=20 each)using a random number table.The infusion rate of propofol was adjusted to maintain the corresponding anesthetic depth with 50≤BIS value 20% of the baseline)was observed.Postoperative delirium was evaluated using Confusion Assessment Method for the Intensive Care Unit(ICU)from 12 h after admission to ICU until discharge from ICU. Results The incidence of postoperative delirium, low cerebral oxygen saturation and minimum rSO2 were significantly lower in group B than in group A(P<0.05). Conclusion Maintaining 35≤ BIS value< 45 during CPB can reduce the development of postoperative delirium and is related to improving intraoperative rSO2 in patients undergoing cardiac valve replacement. Key words: Propofol; Heart valuve, prosthesis; Cardiopulmonary bypass; Delirium