ABSTRACT
Objective:To evaluate the effects of different temperature management strategies on blood-brain barrier (BBB) and postoperative cognitive dysfunction (POCD) in the patients undergoing spinal fixation surgery.Methods:Ninety-six patients, aged 44-78 yr, weighing 45-104 kg, of American Society of Anesthesiology physical status Ⅰ-Ⅲ, undergoing spinal fixation surgery with combined intravenous-inhalational anesthesia, were divided into 3 groups ( n=32 each) by the simple randomization: warming blood transfusion and infusion group (group WBI), active warming group (group AW) and active warming plus selective brain cooling group (group SBC). In WBI group, the fluid for intraoperative intravenous infusion was warmed to 37 ℃ using a medical blood transfusion-infusion warmer.In AW group, warming was maintained using the fluid warming combined with the body surface warming blanket until the end of operation, and the target temperature of the warming blanket was set at 38 ℃.In SBC group, the warming protocol were similar to those previously described in AW group, and selective brain cooling was performed through an electronic ice cap with a set temperature of 4 ℃.Blood samples were collected from the median cubital vein at the end of operation, brain microvascular endothelial cells were isolated and identified by immunomagnetic bead, and the target cells were counted with a fluorescence microscope.The concentration of C-reactive protein in peripheral blood was measured by rate nephelometry on the first day after operation.The extubation time, length of post-anesthesia care unit (PACU) stay, total length of hospital stay, thermal comfortableness score, shivering in PACU, agitation and postoperative fever were recorded.The postoperative recovery was assessed using the 40-item Quality-of-Recovery scale on 7th day after surgery. Results:Compared with WBI group, the incidence of POCD and shivering in PACU, extubation time, length of PACU stay, and serum C-reactive protein concentrations were significantly decreased, and thermal comfortableness score and 40-item Quality-of Recovery scale score were increased in AW group and SBC group ( P<0.05). Compared with AW group, the count of brain microvascular endothelial cells was significantly decreased in SBC group ( P<0.05). Conclusions:Active warming produces no damage to the structure of BBB, and can reduce the development of POCD; active warming combined with selective brain cooling can improve the structural integrity of BBB, but it cannot reduce the development of POCD in the patients undergoing spinal fixation surgery.
ABSTRACT
Objective To evaluate the relationship between inflammatory responses induced by perioperative infection and surgical stress and postoperative cognitive dysfunction in mice. Methods One hundred forty?four healthy male C57BL∕6 mice, aged 8-12 weeks, weighing 20-25 g, were divided into 4 groups ( n=36 each) using a random number table: control group ( group C) , surgery group ( group S) , infection group ( group I) , and infection+surgery group ( group I+S) . In group S, the open reduction and internal fixation was performed after tibial fracture was induced. Lipopolysaccharide ( LPS) 100 μg∕kg was injected intraperitoneally at the same time every day for 5 consecutive days starting from 1 day before surgery in group I. In group I+S, LPS 100 μg∕kg was injected intraperitoneally at the same time every day for 5 consecutive days starting from 1 day before surgery, and the open reduction and internal fixation was per?formed after tibial fracture was induced at 2 h after LPS injection on the day of surgery. Contextual fear con?ditioning test was performed on 1 and 3 days after surgery, and cognitive function was assessed. The rate of freezing time was calculated. The peripheral venous blood samples were collected for determination of plas?ma interleukin?6 ( IL?6) and IL?1β concentrations by enzyme?linked immunosorbent assay. The animals were then sacrificed, and the hippocampi were isolated for determination of IL?6, IL?1β and prostaglandin E2 ( PGE2 ) contents in hippocampal tissues by enzyme?linked immunosorbent assay. Results Compared with group C, the rate of freezing time was significantly decreased on 1 and 3 days after surgery, and the contents of IL?6, IL?1βand PGE2 in hippocampal tissues were significantly increased on 1 and 3 days after surgery in S and I+S groups, the concentrations of plasma IL?6 and IL?1βwere significantly increased on 1 day after surgery, and the concentration of plasma IL?1βwas significantly increased on 3 days after surgery in group S, the concentrations of plasma IL?6 and IL?1β were significantly increased on 1 and 3 days after surgery in I and I+S groups ( P0?05) . Compared with group S or group I, the rate of freezing time was significantly decreased on 1 and 3 days after surgery, and the concentrations of IL?6 and IL?1βin plasma and contents of IL?6, IL?1β and PGE2 in hippocampal tissues were significantly increased on 1 and 3 days after surgery in group I+S ( P<0?01) . Conclusion Inflammatory responses induced by periopera?tive infection and surgical stress can aggravate postoperative cognitive dysfunction in mice.