Daily Anesthesiology Research Analysis

BACKGROUND: Excess function of γ-aminobutyric acid type A (GABA A ) receptors that generate a tonic inhibitory conductance contributes to postanesthetic cognitive impairment. Ketamine may have postoperative cognition-sparing properties; however, whether it reduces excess GABA A receptor function is unknown. This study investigated whether ketamine prevents a sustained anesthetic-triggered increase in GABA A receptor function in vitro and mitigates postanesthetic memory deficits in vivo . METHODS: Murine hippocampal neurons and cortical astrocytes were cocultured and treated for 1 h with an injectable (etomidate) or an inhaled (sevoflurane) anesthetic, with or without ketamine. After 24 h, GABA A receptor-mediated tonic currents were recorded from neurons using whole cell patch clamp. Expression of brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin receptor kinase B (TrkB) was assessed by biotinylation, Western blotting, ELISA, and quantitative polymerase chain reaction. Immunostaining was used to visualize α5 subunit-containing GABA A receptors in neurons. In vivo , adult mice were anesthetized with sevoflurane for 2 h, with or without ketamine, and recognition and spatial memory were assessed 24 and 48 h later, respectively. RESULTS: Ketamine prevented the sustained increase in GABA A receptor-mediated tonic currents triggered by etomidate and sevoflurane. This effect was independent of N -methyl- d -aspartate receptor antagonism and instead was mediated by BDNF-TrkB signaling through a GSK-3β-dependent pathway. Interestingly, ketamine did not alter BDNF levels but increased cell-surface expression of TrkB receptors and thereby facilitated BDNF-TrkB signaling. Ketamine also reduced the anesthetic-induced increase in cell-surface expression of α5 subunit-containing GABA A receptors. In vivo , ketamine prevented deficits in both recognition and spatial memory that occurred after sevoflurane anesthesia. CONCLUSIONS: Ketamine prevents the general anesthetic-induced sustained increase in GABA A receptor function by facilitating BDNF-TrkB signaling. This mechanism is associated with a mitigation of postanesthetic memory deficits in mice.

BACKGROUND: Periarticular local infiltration analgesia has become an important mainstay of multimodal analgesia after elective total hip arthroplasty (THA). However, the role of novel motor-sparing fascial plane blocks-with or without periarticular local infiltration analgesia-has not been fully elucidated for patients undergoing THA. The authors conducted a network meta-analysis evaluating the relative analgesic effectiveness of motor-sparing fascial plane blocks (quadratus lumborum, erector spinae, and pericapsular nerve group blocks) and periarticular local infiltration analgesia for adult patients undergoing THA. METHODS: Randomized trials examining single-injection quadratus lumborum, erector spinae, or pericapsular nerve group blocks, or periarticular local infiltration analgesia, for THA were sought. The primary outcome was area under the curve (AUC) rest pain scores during the period from 0 to 24 h. Secondary outcomes included rest pain scores at 0, 6, 12, and 24 h; postoperative function at 6, 12, and 24 h; analgesic consumption at 0 to 24 h; incidence of opioid-related side effects; and incidence of block-related complications. Network meta-analysis was performed using a frequentist approach. RESULTS: A total of 44 trials (3,579 patients) evaluating the quadratus lumborum block, erector spinae block, pericapsular nerve group block, or periarticular local infiltration analgesia for THA were considered. Network meta-analysis was used to derive the probability of each intervention being the most effective as compared to the others (P score). For AUC 0 to 24 h rest pain, periarticular local infiltration analgesia was the most effective intervention, as demonstrated by a P score of 89%. For postoperative analgesic consumption, the quadratus lumborum block was the most effective intervention, with a P score of 88%. This was followed by the pericapsular nerve group block (74%), the erector spinae block (38%), and periarticular local infiltration analgesia (42%). CONCLUSIONS: Periarticular local infiltration analgesia alone provides the most consistent improvements in postoperative rest pain, analgesic consumption, and functional recovery after THA. The addition of a quadratus lumborum block or pericapsular nerve group block to periarticular local infiltration may further improve analgesic outcomes.

BACKGROUND: Explicit recall occurring during sedation/regional anesthesia is common but has long been assumed to have no sequelae. A prospective cohort study was conducted to determine the incidence of explicit recall experience under sedation/regional anesthesia, as well as to assess the recall experiences that are associated with psychological consequences. METHODS: The study prospectively recruited 2,500 adults who underwent elective total hip or knee arthroplasty under sedation/regional anesthesia from September 2021 to March 2024 at University Hospital in London, Ontario, Canada. The primary exposure was recall experience, assessed using the modified Brice questionnaire. The co-primary outcomes included probable depression (defined as a Patient Health Questionnaire score of 8 or higher) and suspected posttraumatic stress disorder (PTSD) symptoms (defined as a Post-traumatic Stress Disorder Checklist for Civilians score of 13 or higher) at 6 weeks postoperatively. The association between specific recall experiences and the co-primary outcomes was evaluated by multivariable regression analysis. Additionally, the incidence and mental health burden related to the psychological effects of surgery in the entire cohort were assessed. RESULTS: A total of 2,138 patients were included in the final analysis. Explicit recall was reported by 475 participants (22.2%) but was not associated with the co-primary outcomes. Regarding surgery's overall impact, 61 participants (5%) developed new probable depression, 105 participants (5%) reported suspected PTSD, and 95 patients (4.4%) developed new suicidal ideation postoperatively. The authors estimated that 1 in 18 patients required new psychiatric consultation. CONCLUSIONS: Explicit recall per se during sedation/regional anesthesia did not increase the odds of developing psychiatric illness. Surgery itself carries significant risks of triggering depression and PTSD that are severe enough to reach levels associated with suicidal ideation, requiring immediate mental care. This study reveals a significant, yet underappreciated, mental healthcare burden.