Boston Naming Test as a Screening Tool for Early Postoperative Cognitive Dysfunction in Elderly Patients After Major Noncardiac Surgery.

PURPOSE: The Boston naming test (BNT), as a simple, fast, and easily administered neuropsychological test, was demonstrated to be useful in detecting language function. In this study, BNT was investigated whether it could be a screening tool for early postoperative cognitive dysfunction (POCD). METHODS: This prospective observational cohort study included 132 major noncardiac surgery patients and 81 nonsurgical controls. All participants underwent a mini-mental state examination (MMSE) and BNT 1 day before and 7 days after surgery. Early POCD was assessed by reliable change index and control group results. RESULTS: Seven days after surgery, among 132 patients, POCD was detected in 30 (22.7%) patients (95% CI, 15.5%-30.0%) based on MMSE, and 45 (34.1%) patients (95% CI, 26.3%-41.9%) were found with postoperative language function decline based on BNT and MMSE. Agreement between the BNT spontaneous naming and MMSE total scoring was moderate (Kappa .523), and the sensitivity of BNT spontaneous naming for detecting early POCD was .767. Further analysis showed that areas under receiver operating characteristics curves (AUC) did not show statistically significant differences when BNT spontaneous naming (AUC .862) was compared with MMSE language functional subtests (AUC .889), or non-language functional subtests (AUC .933). CONCLUSION: This study indicates the feasibility of implementing the BNT spontaneous naming test to screen early POCD in elderly patients after major noncardiac surgery.

Fast green FCF prevents postoperative cognitive dysfunction via the downregulation of the P2X4 receptor in mice.

Postoperative cognitive dysfunction (POCD) is a decline in cognitive function affecting the mental health of aged patients after surgery. The pathological mechanisms underlying POCD have not yet been clarified. The overexpression of the P2X4 receptor in the central nervous system (CNS) was reported to be associated with the onset of POCD. Fast green FCF (FGF), a widely used food dye, could decrease the expression of the P2X4 receptor in the CNS. This study aimed to explore whether FGF could prevent POCD via the down-regulation of CNS P2X4 receptor. Exploratory laparotomy under the anesthesia of fentanyl and droperidol was carried to establish an animal model of POCD in 10-12-months-olds mice. FGF significantly attenuated cognitive impairments and down-regulated the expression of the P2X4 receptor induced by surgery in mice. Moreover, the blockade of CNS P2X4 receptor by intrahippocampal injection of 5-BDBD induced cognitive-enhancing effects on POCD mice. In addition, the effects of FGF were abolished by ivermectin, which is a positive allosteric modulator of the P2X4 receptor. FGF also inhibited M1 polarization of microglia cells, decreased the phosphorylation of nuclear factor-κB (NF-κB), and reduced the production of pro-inflammatory cytokines. These results suggested that FGF produced anti-POCD cognitive-enhancing effects via down-regulation of the P2X4 receptor-associated neuroinflammation, providing a support that FGF might be a potential treatment for POCD.

Effects of different types of non-cardiac surgical trauma on hippocampus-dependent memory and neuroinflammation.

Background: Older individuals have been reported to suffer from cognitive disorders after surgery. Various types of surgical trauma have been used to establish postoperative cognitive dysfunction (POCD) animal models in preclinical studies. However, few comparative analyses of these animal models were conducted. Methods: Tibial surgery, abdominal surgery, and extended abdominal surgery were performed on aged ICR mice to establish POCD models. Behavioral tests included open field, novel object recognition, fear conditioning, and Morris water maze tests. The Z-score methodology was adopted to obtain a comprehensive and integrated memory performance profile. The changes in hippocampal neuroinflammation were analyzed by ELISA, PCR, and immunofluorescence. Results: In this study, we found that each type of non-cardiac surgical trauma has a different effects on locomotor activity. Tibial and extended abdominal surgeries led to more significant cognitive impairment than abdominal surgery. Inflammatory cytokines peaked on postoperative day 1 and decreased to control levels on days 3 and 7. Hippocampal neuroinflammation indicators between the three surgery types on postoperative day 1 had no statistical differences. Conclusion: Overall, the type and intensity of non-cardiac surgical trauma can affect cognitive behavioral outcomes and central inflammation. The shortcomings and emerging issues of POCD animal research methods need to be further studied and solved.

Role of P2X4/NLRP3 Pathway-Mediated Neuroinflammation in Perioperative Neurocognitive Disorders.

Several studies have demonstrated that neuroinflammation is the key to perioperative neurocognitive disorders (PND); however, the specific mechanism postsurgery and anesthesia has not yet been fully clarified. The present study is aimed at exploring the effects of P2X4/NLRP3 signaling pathway in neuroinflammation and cognitive impairment after surgery. 12-14-month-old male C57BL/6 mice undergoing open tibial fracture surgery by sevoflurane anesthesia were administered P2X4R inhibitor 5-BDBD or saline was intraperitoneally for 3 consecutive days after surgery. Then, the animals were subjected to Morris water maze test or sacrificed to collect the hippocampus. The level of P2X4R and NLRP3 was estimated by Western blot, the activation of microglia was detected via immunohistochemistry, and the expression of TNF-α, IL-1ß, and IL-6 was quantified by enzyme-linked immunosorbent assay. These results indicated that tibial surgery caused cognitive impairment, increased the expression of P2X4R and NLRP3, and aggravated the neuroinflammation and microglia activation. However, intraperitoneal injection of 5-BDBD attenuated these effects. In conclusion, these findings indicated that the P2X4/NLRP3 pathway might be involved in the pathophysiology of PND.

High-Pressure Pneumoperitoneum Aggravates Surgery-Induced Neuroinflammation and Cognitive Dysfunction in Aged Mice.

Postoperative cognitive dysfunction (POCD) is a common complication after surgery, especially in aged patients. Neuroinflammation has been closely associated with the development of POCD. While the contribution of pneumoperitoneum to the systemic inflammation has been well documented, the effect of pneumoperitoneal pressure on neuroinflammation and postoperative cognitive function remains unclear. In this study, we showed that high-pressure pneumoperitoneum promoted the postoperative neuroinflammation and microglial activation in the hippocampus and aggravated the postoperative cognitive impairment in aged mice. These results support the requirement to implement interventions with lower intra-abdominal pressure, which allows for adequate exposure of the operative field rather than a routine pressure.

Melatonin and Rapamycin Attenuate Isoflurane-Induced Cognitive Impairment Through Inhibition of Neuroinflammation by Suppressing the mTOR Signaling in the Hippocampus of Aged Mice.

Melatonin exerts neuroprotective effects on isoflurane-induced cognitive impairment. However, the underlying mechanism has yet to be elucidated. The present study sought to determine if melatonin confers its beneficial effects by acting on mammalian target of rapamycin (mTOR) and attenuates the neuroinflammation in the hippocampus of aged mice. A total of 72 male C57BL/6 mice, 16-month-old, were randomly and equally divided into six groups: (1) the control group (CON); (2) the rapamycin group (RAP); (3) the melatonin group (MEL); (4) the isoflurane group (ISO); (5) the rapamycin + isoflurane group (RAP + ISO); and (6) the melatonin + isoflurane group (MEL + ISO). RAP, RAP + ISO, MEL, MEL + ISO groups received 1 mg/kg/day mTOR inhibitor rapamycin solution or 10 mg/kg/day melatonin solution, respectively, intraperitoneally at 5:00 p.m. for 14 days consecutively. Mice in the CON and ISO groups were administered an equivalent volume of saline. Subsequently, ISO, RAP + ISO, and MEL + ISO groups were exposed to inhale 2% isoflurane for 4 h; the CON, RAP, and MEL mice received only the vehicle gas. Then, the memory function and spatial learning of the mice were examined via the Morris water maze (MWM) test. mTOR expression was detected via Western blot, whereas the concentration of inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6 and that of melatonin was quantified with enzyme-linked immunosorbent assay (ELISA). Melatonin and rapamycin significantly ameliorated the isoflurane-induced cognitive impairment and also led to a decrease in the melatonin levels as well as the expression levels of TNF-α, IL-1ß, IL-6, and p-mTOR in the hippocampus. In conclusion, these results showed that melatonin and rapamycin attenuates mTOR expression while affecting the downstream proinflammatory cytokines. Thus, these molecular findings could be associated with an improved cognitive function in mice exposed to isoflurane.

The Investigation of Hippocampus-Dependent Cognitive Decline Induced by Anesthesia/Surgery in Mice Through Integrated Behavioral Z-Scoring.

OBJECTIVE: Patients undergoing major surgeries may experience certain cognitive decline, which is known as postoperative delirium (POD) or postoperative cognitive dysfunction (POCD). We employed integrated behavioral Z-scoring introduced by Guilloux et al. (2011) to investigate the effects of fracture fixation under anesthesia on hippocampus-dependent memory in mice. METHODS: ICR mice (12-14 months) underwent stabilized tibial fracture operation under sevoflurane anesthesia. They were subjected to a battery of successive hippocampus-dependent tests following surgery, including open field test (OF), novel object recognition (NOR), fear conditioning test (FC), and Morris water maze (MWM). The integrated behavioral Z-scoring was applied to assess the hippocampus-dependent memory after anesthesia/surgery, and the association between the integrated behavioral Z-scores and hippocampal pro-inflammatory cytokines was explored. RESULTS: Mice after anesthesia/surgery were found to have impaired hippocampus-dependent memory in NOR, FC, and MWM but with different degrees in these aspects as represented by P-value and effect size. The integrated memory Z-scores based on principal parameters of the above three tests can reduced the variability and increase the comprehensiveness of behavioral results. However, we found no statistic associations between hippocampal pro-inflammatory cytokines and the integrated Z-scores, as the elevated cytokines quickly return to normal on postoperative day 3 and/or day 7. CONCLUSION: The integrated Z-score methodology could facilitate the interpretation of the anesthesia/surgery induced cognitive decline in mice and robustly quantify the behavioral phenotyping of hippocampus-dependent memory.

Effects of perioperative tight glycemic control on postoperative outcomes: a meta-analysis.

Background The optimal glycemic target during the perioperative period is still controversial. We aimed to explore the effects of tight glycemic control (TGC) on surgical mortality and morbidity. Methods PubMed, EMBASE and CENTRAL were searched from January 1, 1946 to February 28, 2018. Appropriate trails comparing the postoperative outcomes (mortality, hypoglycemic events, acute kidney injury, etc.) between different levels of TGC and liberal glycemic control were identified. Quality assessments were performed with the Jadad scale combined with the allocation concealment evaluation. Pooled relative risk (RR) and 95% CI were calculated using random effects models. Heterogeneity was detected by the I2 test. Results Twenty-six trials involving a total of 9315 patients were included in the final analysis. The overall mortality did not differ between tight and liberal glycemic control (RR, 0.92; 95% CI, 0.78-1.07; I 2 = 20.1%). Among subgroup analyses, obvious decreased risks of mortality were found in the short-term mortality, non-diabetic conditions, cardiac surgery conditions and compared to the very liberal glycemic target. Furthermore, TGC was associated with decreased risks for acute kidney injury, sepsis, surgical site infection, atrial fibrillation and increased risks of hypoglycemia and severe hypoglycemia. Conclusions Compared to liberal control, perioperative TGC (the upper level of glucose goal ≤150 mg/dL) was associated with significant reduction of short-term mortality, cardic surgery mortality, non-diabetic patients mortality and some postoperative complications. In spite of increased risks of hypoglycemic events, perioperative TGC will benefits patients when it is done carefully.

The Association between Pre-existing Diabetes Mellitus and Pressure Ulcers in Patients Following Surgery: A Meta-analysis.

Uncertainty exists about the role of diabetes in the development of surgery-related pressure ulcers. Therefore, we conducted a meta-analysis to explore the association between pre-existing diabetes mellitus and pressure ulcers among patients after surgery. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random effects models. Thirteen eligible studies of 2367 patients in total and 12,053 controls were included in the final analysis. Compared with patients without diabetes, the pooled odds ratio (OR) of the incidence of pressure ulcers in diabetic patients was 1.74 [95% confidence interval (CI) = 1.40-2.15, I(2 )= 51.1%]. Estimates by type of surgery suggested similar results in cardiac surgery [OR = 2.00, 95% CI = 1.42-2.82, I(2 )= 0%], in general surgery [OR = 1.75, 95% CI = 1.42-2.15, I(2 )= 0%], and in major lower limb amputations [OR = 1.65, 95% CI = 1.01-2.68, I(2 )= 0%] for diabetic patients versus non-diabetic controls. We did not find an increased incidence of pressure ulcers in diabetic patients undergoing hip surgery compared with non-diabetic controls [OR = 1.46, 95% CI = 0.62-3.47, I(2 )= 93.1%]. The excess risk of pressure ulcers associated with pre-existing diabetes was significantly higher in patients undergoing surgery, specifically in patients receiving cardiac surgery. Further studies should be conducted to examine these associations in other types of surgery.