Postoperative cognitive dysfunction (POCD) affects the outcome of millions of patients each year. Aging is a risk factor for POCD. Here, we showed that surgery induced learning and memory dysfunction in adult mice. Transplantation of feces from surgery mice but not from control mice led to learning and memory impairment in non-surgery mice. Low intensity exercise improved learning and memory in surgery mice. Exercise attenuated surgery-induced neuroinflammation and decrease of gut microbiota diversity. These exercise effects were present in non-exercise mice receiving feces from exercise mice. Exercise reduced valeric acid, a gut microbiota product, in the blood. Valeric acid worsened neuroinflammation, learning and memory in exercise mice with surgery. The downstream effects of exercise included attenuating growth factor decrease, maintaining astrocytes in the A2 phenotypical form possibly via decreasing C3 signaling and improving neuroplasticity. Similar to these results from adult mice, exercise attenuated learning and memory impairment in old mice with surgery. Old mice receiving feces from old exercise mice had better learning and memory than those receiving control old mouse feces. Surgery increased blood valeric acid. Valeric acid blocked exercise effects on learning and memory in old surgery mice. Exercise stabilized gut microbiota, reduced neuroinflammation, attenuated growth factor decrease and preserved neuroplasticity in old mice with surgery. These results provide direct evidence that gut microbiota alteration contributes to POCD development. Valeric acid is a mediator for this effect and a potential target for brain health. Low intensity exercise stabilizes gut microbiota in the presence of insult, such as surgery.

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Background: Perioperative, modifiable factors contributing to perioperative neurocognitive disorders (PND) have not been clearly defined. Objective: To determine the contribution of anesthesia lengths and the degrees of surgical trauma to PND and neuroinflammation, a critical process for PND. Methods: Three-month-old C57BL/6J mice were subjected to 2 h or 6 h isoflurane anesthesia plus a 5 min or 15 min left common carotid artery exposure (surgery) in a factorial design (two factors: anesthesia with two levels and surgery with three levels). Their learning and memory were tested by Barnes maze and novel object recognition paradigms. Blood, spleen, and hippocampus were harvested for measuring interleukin (IL)-6 and IL-1β. Eighteen-month-old C57BL/6J mice (old mice) were subjected to 6 h isoflurane anesthesia or 2 h isoflurane anesthesia plus 15 min surgery and then had learning and memory tested. Results: Three-month-old mice with 15 min surgery (long surgery) under 2 h or 6 h anesthesia performed poorly in the learning and memory tests compared with controls. Anesthesia alone or anesthesia plus 5 min surgery did not affect mouse performance in these tests. Similarly, only mice with long surgery but not mice with other experimental conditions had increased IL-6 and IL-1β in the blood, spleen, and hippocampus and decreased spleen weights. Splenocytes were found in the hippocampus after surgery. Similarly, old mice with long surgery but not the mice with isoflurane anesthesia alone had poor performance in the Barnes maze and novel object recognition tests. Conclusion: Surgical trauma, but not anesthesia, contributes to the development of PND and neuroinflammation. Splenocytes may modulate these processes.

Aims Postoperative cognitive dysfunction (POCD) is a common and significant syndrome. Our previous studies have shown that surgery reduces dendritic arborization and spine density and that environment enrichment (EE) reduces POCD. Neuroligin 1 is a postsynaptic protein involved in the formation of postsynaptic protein complex. This study was designed to determine the role of neuroligin 1 in the protection of EE against POCD and the mechanisms for EE to affect neuroligin 1 expression. Methods Eight‐week‐old C57BL/6J male mice with or without EE for 3, 7, or 14 days had right carotid artery exposure under isoflurane anesthesia. An anti‐neuroligin 1 antibody at 1.5 µg/mouse was injected intracerebroventricularly at one and two weeks before the surgery. Mice were subjected to the Barnes maze and fear conditioning tests from one week after the surgery. Cerebral cortex and hippocampus were harvested after surgery. Results Mice with surgery had poorer performance in the Barnes maze and fear conditioning tests than control mice. EE for 2 weeks, but not EE for 3 or 7 days, improved the performance of surgery mice in these tests. Surgery reduced neuroligin 1 in the hippocampus. Preoperative EE for 2 weeks attenuated this reduction. The anti‐neuroligin 1 antibody worsened the performance of mice with surgery plus EE in the Barnes maze and fear conditioning tests. Surgery increased histone deacetylase activity and decreased the acetylated histone in the hippocampus. EE attenuated these surgery effects. Conclusion Our results suggest that preoperative EE for 2 weeks reduces POCD. This effect may be mediated by preserving neuroligin 1 expression via attenuating surgery‐induced epigenetic dysregulation in the brain.

Background: A low first-pass success rate of radial artery cannulation was obtained when using the conventional palpation technique(C-PT) or ultrasound-guided techniques, we therefore evaluate the effect of a modified long-axis in-plane ultrasound technique (M-LAINUT) in guiding radial artery cannulation in adults. Methods：We conducted a prospective, randomized and controlled clinical trial of 288 patients undergoing radial artery cannulation. Patients were randomized 1:1 to M-LAINUT or C-PT group at fujian medical university union hospital between 2017 and 2018. Radial artery cannulation was performed by three anesthesiologists with different experience. The outcome was the first and total radial artery cannulation success rates, the number of attempts and the cannulation time. Results: 285 patients were statistically analyzed. The success rate of first attempt was 91.6% in the M-LAINUT group (n=143) and 57.7% in the C-PT group (n=142; P<0.001) (odds ratio, 7.9; 95% confidence interval, 4.0-15.7). The total success rate (≤5 min and ≤3 attempts) in the M-LAINUT group was 97.9%, compared to 84.5% in the palpation group (p <0.001) (odds ratio, 8.5; 95% confidence interval, 2.5-29.2). The total cannulation time was shorter and the number of attempts was fewer in the M-LAINUT group than that in the C-PT group (p <0. 05). Conclusion: Modified long-axis in-plane ultrasound-guided radial artery cannulation can increase the first and total radial artery cannulation success rates, reduce the number of attempts and shorten the total cannulation time in adults.

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Using ETS-guided anesthesia and maintaining the sevoflurane concentration (0.7-1.3 MAC) can decrease the incidence of patient awareness during endoscopic surgery.