Effects Of Dexmedetomidine On Postoperative Delirium And Perioperative Ngal Levels In Aged Patients With Hip Or Knee Arthroplasty

Objective To observe the effects of dexmedetomidine (DEX) on the incidence of postoperative delirium (POD) and plasma/urine neutrophil gelatinase associated-lipocalin (NGAL) concentration in aged patients undergoing unilateral total hip or knee arthroplasty. To investigate the predictive or diagnostic value of NGAL for POD in elderly patients undergoing unilateral total hip or knee arthroplasty.Methods We adopted a prospective, randomized, double-blind, placebo-controlled study design. Sixty-nine elderly patients were randomly divided into 2 groups:DEX group(n=35, One patient was exited because of unplanned reoperation) and control group(n=34). Total intravenous propofol anesthesia was used to maintain suitable depth of anesthesia. The DEX group patients were given a loading dosage (0.4ug·kg’l·h-1 intravenous infusion for 10 min) of DEX after the induction of general anesthesia, and followed by continuous infusion (0.2ug·kg-1·h-1) until the end of operation. The control group patients were given 0.9% saline solution instead of DEX at the same time point. The delirium was evaluated with confusion assessment method for ICU (CAM-ICU) at preanesthesia, postoperative 24h,48h and 72h. The plasma and urine NGAL concentration were measured at four points of time (preoperative, extubation, postoperative 24h and 72h) by enhanced immune nephelometry.Results There were 7 cases in the control group occurred POD within 72 hours postoperative, the incidence was 20.58%; the test group had 3 cases, the incidence was 8.82%(P>0.05). Compared with preoperative, the levels of plasma/urine NGAL were markedly increased and reached peak at postoperative 24h. Compared with control group, the plasma/urine NGAL concentration of DEX group was markedly decreased at each detection time point of postoperative (P<0.001).The ROC area under the curve (AUC) of plasma NGAL concentration for predict or diagnosis of POD was greater than that of urine NGAL concentration after tracheal extubation (0.772 vs 0.736). The AUC of urine NGAL for predict or diagnosis of POD was greater than that of plasma NGAL at postoperative 24h (0.785 vs 0.679).Conclusion The plasma/urine NGAL concentration at extubation and postoperative 24h may be helpful to predict or diagnose of POD in aged patients undergoing unilateral total hip or knee arthroplasty. Intraoperative infusion of low dose dexmedetomidine can decrease the postoperative concentration of plasma/urine NGAL in aged patients undergoing unilateral hip, knee arthroplasty.