Preoperative Acute Pain Is Associated with Postoperative Delirium. Ding Xian,Gao Xiang,Chen Qizhong,Jiang Xuliang,Li Yi,Xu Jingjing,Qin Guowei,Lu Shunmei,Huang Dongxiao Pain medicine (Malden, Mass.) BACKGROUND:Studies have provided some evidence that pain is a risk factor for postoperative delirium (POD). Therefore, we investigated the relationship between preoperative pain and POD after noncardiac surgery. METHODS:POD was assessed with the Montreal Cognitive Assessment, and preoperative cognition was assessed with the Mini-Mental State Examination. Plasma C-reactive protein (CRP) was detected by enzyme-linked immunosorbent assay before surgery. Preoperative pain was classified by its duration before surgery as chronic pain (lasting more than 1 month), acute pain (lasting less than 1 month), or no pain (no obvious pain). Multiple linear regression was used to adjust for confounding. RESULTS:From October 15, 2018, through August 12, 2019, a total of 67 patients were randomized; 7 were excluded because they were discharged before the seventh postoperative day. The prevalence of POD was significantly higher in the acute pain group (13 of 20; 65%) than in the chronic pain group (5 of 20; 25%) or the no pain group (6 of 20; 30%) (P = 0.019), indicating that delirium is associated with preoperative acute pain. The plasma level of preoperative CRP was also higher in the acute pain group than in the other two groups (mean [interquartile range]: 10.7 [3.3, 29.3] vs 1 [0.5, 3.8]mg/l; P < 0.001), suggesting that elevated preoperative plasma levels of CRP were associated with delirium. CONCLUSIONS:Preoperative acute pain was associated with POD, and increased plasma levels of CRP provide a marker. In addition, we found that illiteracy and advanced age were risk factors for POD. 10.1093/pm/pnaa314

Acute postoperative pain exacerbates neuroinflammation and related delirium-like cognitive dysfunction in rats. Koyama Tsuyoshi,Kawano Takashi,Iwata Hideki,Aoyama Bun,Eguchi Satoru,Nishigaki Atsushi,Yamanaka Daiki,Tateiwa Hiroki,Shigematsu-Locatelli Marie,Locatelli Fabricio M,Yokoyama Masataka Journal of anesthesia The acute neuroinflammatory response to surgery may play a key pathogenic role in postoperative delirium (POD). Here, we investigated the contribution of acute postoperative pain to neuroinflammation and related delirium-like behaviors after surgery in adult and aged rats. Animals were assigned into four groups: control, abdominal surgery, surgery with analgesia using local ropivacaine, and surgery with analgesia using systemic morphine. Pain was assessed by the Rat Grimace Scale (RGS). Trace and context memory retention was evaluated following trace fear conditioning during the first 2 days after surgery. Pro-inflammatory cytokines in medial prefrontal cortex and hippocampus were measured by enzyme-linked immunosorbent assay. In both age groups, the RGS increased significantly from baseline until 6 h after surgery. The postoperative analgesia with either local or systemic regimens comparably alleviated the RGS increase in adult and aged animals. The two analgesic regimens attenuated the surgery-induced trace and context memory deficits, as well as cytokines overproduction in both medial prefrontal cortex and hippocampus. No age-related differences were found in the neuro-cognitive effectiveness of postoperative analgesia. Our experimental findings provide proof-of-concept for adequate postoperative pain management as one of the main preventive strategies of POD. 10.1007/s00540-019-02635-3