Effect of parecoxib sodium combined with dexmedetomidine on postoperative levels of plasma excitatory aminoacid and beta-amyloid protein in jugular bulb venous of elderly patients

Abstract

Objective To investigate the effect of parecoxib sodium combined with dexmedetomidine on postoperative levels of plasma excitatory aminoacid and beta-amyloid protein (β-AP) in jugular bulb venous of elderly patients. Methods A total of 135 patients of either sex, aged 65-79 yr, weighing 47-76 kg, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, undergoing elective open reduction and internal fixation after tibial fracture and hip replacement, were divided into 3 groups (n=45 each) using a random number table: parecoxib sodium group (group P), dexmedetomidine group (group D) and parecoxib sodium combined with dexmedetomidine group (group PD). In group P, parecoxib sodium 40 mg (diluted to 5 ml in normal saline) was injected intravenously at 15 min before induction of anesthesia.In group D, dexmedetomidine was intravenously infused at a loading dose of 0.5 μg/kg over 15 min starting from 15 min before induction of anesthesia, followed by an infusion of 0.5 μg·kg-1·h-1 until the end of surgery.In group PD, parecoxib sodium 40 mg (diluted to 5 ml in normal saline) was intravenously injected at 15 min before induction of anesthesia, and dexmedetomidine was intravenously infused at a loading dose of 0.5 μg/kg over 15 min followed by an infusion of 0.5 μg·kg-1·h-1 until the end of surgery at the same time.At 15 min before induction of anesthesia (T0), at the end of surgery (T1) and at 24, 48 and 72 h after surgery (T2-4), jugular bulb venous blood samples were taken for determination of concentrations of glutamate and aspartate in plasma (by reversed phase high-performance liquid chromatography) and β-AP (by enzyme-linked immunosorbent assay). Cognitive function was assessed at 1 day before surgery and 7 days after surgery using a battery of neuropsychologic tests including Wechsler Memory Scale, Digit Span (Forward and Backward), visual recognition and associative learning, Wechsler Adult Intelligence Scale and Trail Making Test Part A. The occurrence of postoperative cognitive dysfunction was recorded at 7 days after surgery. Results Compared with P and D groups, the concentrations of plasma glutamate at T2-3, plasma aspartate at T2 and β-AP at T1 and incidence of postoperative cognitive dysfunction were significantly decreased in group PD (P< 0.05). Conclusion The mechanism by which parecoxib sodium combined with dexmedetomidine decreases the occurrence of POCD may be related to inhibiting the levels of excitatory aminoacid and β-AP in brain tissues of elderly patients. Key words: Cyclooxygenase inhibitors; Dexmedetomidine; Excitatory amino acids; Amyloid beta-protein; Cognition disorders; Aged