British journal of anaesthesia最新文献

Background: Nitrous oxide (N₂O) is a potent greenhouse gas that contributes significantly to the healthcare sector's carbon footprint. Pre-utilisation losses of N₂O are up to 95%. Decommissioning manifolds can reduce these losses.

Methods: Hospitals in our Greater London research network with at least one active N₂O manifold were included in the Nitrous Oxide Manifold and Other Reduction of Emissions (NoMoreGas) study. N₂O utilisation data were collected continuously over 5 days and extrapolated over a year, in addition to collecting procurement records from the preceding financial year. The primary outcome was the discrepancy between clinically utilised N₂O and the quantity procured by hospitals, referred to as the 'N₂O gap'. Secondary outcomes included anaesthetists' self-reported utilisation of N₂O and their opinions on manifold decommissioning.

Results: Eighteen of 53 hospitals were included. In total, 6 487 200 L of N₂O were procured with a median (IQR) of 304 200 (183 600-473 400) L per site. During the 5-day data collection period, sites utilised a median (IQR) of 501 (42-1409) L of N₂O. Extrapolating over a year resulted in a median (IQR) annual utilisation of 36 573 (3066-102 857) L per site and a total of 1 175 348 L. This represented an estimated 18% of the N₂O procured, suggesting pre-utilisation losses of 5 311 852 L. Among surveyed anaesthetists, 70% (n=309) reported using N₂O within the previous year, with one-third (n=97) using it once a week or more. There was widespread support for decommissioning manifolds.

Conclusions: Consistent with other reports, the data demonstrate a substantial discrepancy between the quantities of N₂O procured and utilised clinically, indicative of significant pre-utilisation losses. Our findings support the decommissioning of N₂O manifolds for environmental and economic benefits.

Background: Plexus injury results in lifelong suffering from flaccid paralysis, sensory loss, and intractable pain. For this clinical problem, regenerative medicine concepts set high expectations. However, it is largely unknown how dorsal root ganglia (DRG) are affected by accidental deafferentation.

Methods: Here, we phenotyped DRG of a clinically and MRI-characterised cohort of 13 patients with plexus injury. Avulsed DRG were collected during reconstructive nerve surgery. For control, we used DRG from forensic autopsy. The cellular composition of the DRG was analysed in histopathological slices with multicolour high-resolution immunohistochemistry, tile microscopy, and deep-learning-based bioimage analysis. We then sequenced the bulk RNA of corresponding DRG slices.

Results: In about half of the patients we found loss of the typical DRG units consisting of neurones and satellite glial cells. The DRG cells were replaced by mesodermal/connective tissue. In the remaining patients, the cellular units were well preserved. Preoperative plexus MRI neurography was not able to distinguish the two types. Patients with 'neuronal preservation' had less maximum pain than patients with 'neuronal loss'. Arm function improved after nerve reconstruction, but severe pain persisted. Transcriptome analysis of preserved DRGs revealed expression of subtype-specific sensory neurone marker genes, but downregulation of neuronal attributes. Furthermore, they showed signs of ongoing inflammation and connective tissue remodelling.

Conclusions: Patients with plexus injury separate into two groups with either neuronal preservation or neuronal loss. The former could benefit from anti-inflammatory therapy. For the latter, studies should explore mechanisms of neuronal loss especially for regenerative approaches.

Clinical trial registration: DRKS00017266.

Background: Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are common after noncardiac surgery. Postsurgical pain is frequent and can persist as chronic postsurgical pain (CPSP). The association between postsurgical pain and POD or POCD is biologically plausible. We conducted this systematic review to evaluate the association between acute postsurgical pain or CPSP and POD or POCD in adults undergoing noncardiac surgery.

Methods: We followed Preferred Reporting Items for Systematic Review and Meta-Analyses. We searched MEDLINE, EMBASE, Cochrane, CINAHL and PSYCHINFO up to May 2023. We included cohort, case-control, and cross-sectional studies of any language. Pairs of reviewers independently screened studies, extracted data and assessed the risk of bias using the CLARITY tool and the Joanna Briggs Institute checklist. We assessed the certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. Where possible, we conducted random-effects meta-analyses to summarise our findings.

Results: We analysed 30 studies (>9000 participants) that assessed the association between acute postoperative pain and POD/POCD. Dose-response meta-analyses found that postoperative pain intensity was associated with occurrence of POD (adjusted relative risk [aRR]/unit of pain intensity: 1.26; 95% confidence interval [CI]: 1.17-1.35; low certainty of evidence) and risk of developing POD (aRR/unit of pain intensity: 1.18; 95% CI: 1.08-1.30; low certainty of evidence). There was very low certainty of evidence regarding the association between postoperative pain and POCD. No studies assessed the association between CPSP and POCD. Residual confounding and substantial methodological variability between studies prevented pooling data from many of the included studies and lowered certainty of evidence.

Conclusions: Dose-response meta-analyses found that postoperative pain intensity was associated with occurrence of and risk of developing POD.

Systematic review protocol: PROSPERO-CRD42021192105.

Introduction: Intravenous lidocaine is increasingly used as a nonopioid analgesic, but how it acts in the brain is incompletely understood. We conducted a functional MRI study of pain response, resting connectivity, and cognitive task performance in volunteers to elucidate the effects of lidocaine at the brain-systems level.

Methods: We enrolled 27 adults (age 22-55 yr) in this single-arm, open-label study. Pain response task and resting-state functional MRI scans at 3 T were obtained at baseline and then with a constant effect-site concentration of lidocaine. Electric nerve stimulation, titrated in advance to 7/10 intensity, was used for the pain task (five times every 10 s). Group-level differences in pain task-evoked responses (primary outcome, focused on the insula) and in resting connectivity were compared between baseline and lidocaine conditions, using adjusted P<0.05 to account for multiple comparisons. Pain ratings and performance on a brief battery of computer-based tasks were also recorded.

Results: Lidocaine infusion was associated with decreased pain-evoked responses in the insula (left: Z=3.6, P<0.001, right: Z=3.6, P=0.004) and other brain areas including the cingulate gyrus, thalamus, and primary sensory cortex. Resting-state connectivity showed significant diffuse reductions in both region-to-region and global connectivity measures with lidocaine. Small decreases in pain intensity and unpleasantness and worse memory performance were also seen with lidocaine.

Conclusions: Lidocaine was associated with broad reductions in functional MRI response to acute pain and modulated whole-brain functional connectivity, predominantly decreasing long-range connectivity. This was accompanied by small but significant decreases in pain perception and memory performance.

Clinical trial registration: NCT05501600.

Background: The accurate diagnosis of heart failure (HF) before major noncardiac surgery is frequently challenging. The impact of diagnostic accuracy for HF on intraoperative practice patterns and clinical outcomes remains unknown.

Methods: We performed an observational study of adult patients undergoing major noncardiac surgery at an academic hospital from 2015 to 2019. A preoperative clinical diagnosis of HF was defined by keywords in the preoperative assessment or a diagnosis code. Medical records of patients with and without HF clinical diagnoses were reviewed by a multispecialty panel of physician experts to develop an adjudicated HF reference standard. The exposure of interest was an adjudicated diagnosis of heart failure. The primary outcome was volume of intraoperative fluid administered. The secondary outcome was postoperative acute kidney injury (AKI).

Results: From 40 659 surgeries, a stratified subsample of 1018 patients were reviewed by a physician panel. Among patients with adjudicated diagnoses of HF, those without a clinical diagnosis (false negatives) more commonly had preserved left ventricular ejection fractions and fewer comorbidities. Compared with false negatives, an accurate diagnosis of HF (true positives) was associated with 470 ml (95% confidence interval: 120-830; P=0.009) lower intraoperative fluid administration and lower risk of AKI (adjusted odds ratio:0.39, 95% confidence interval 0.18-0.89). For patients without adjudicated diagnoses of HF, non-HF was not associated with differences in either fluids administered or AKI.

Conclusions: An accurate preoperative diagnosis of heart failure before noncardiac surgery is associated with reduced intraoperative fluid administration and less acute kidney injury. Targeted efforts to improve preoperative diagnostic accuracy for heart failure may improve perioperative outcomes.

Background: Delaying surgery after a major cardiovascular event might reduce adverse postoperative outcomes. The time interval represents a potentially modifiable risk factor but is not well studied.

Methods: This was a longitudinal retrospective population-based cohort study, linking data from Hospital Episode Statistics for NHS England and the Myocardial Ischaemia National Audit Project. Adults undergoing noncardiac, non-neurologic surgery in 2007-2018 were included. The time interval between a preoperative cardiovascular event and surgery was the main exposure. The outcomes of interest were acute coronary syndrome (ACS), acute myocardial infarction (AMI), cerebrovascular accident (CVA) within 1 year of surgery, unplanned readmission (at 30 days and 1 year), and prolonged length of stay. Multivariable logistic regression models with restricted cubic splines were used to estimate adjusted odds ratios (aORs; age, sex, socioeconomic deprivation, and comorbidities).

Results: In total, 877 430 people had a previous cardiovascular event and 20 582 717 were without an event. CVA, ACS, and AMI in the year after elective surgery were more frequent after prior cardiovascular events (adjusted hazard ratio 2.12, 95% confidence interval [CI] 2.08-2.16). Prolonged hospital stay (aOR 1.36, 95% CI 1.35-1.38) and 30-day (aOR 1.28, 95% CI 1.25-1.30) and 1-yr (aOR 1.60, 95% CI 1.58-1.62) unplanned readmission were more common after major operations in those with a prior cardiovascular event. After adjusting for the time interval between preoperative events until surgery, elective operations within 37 months were associated with an increased risk of postoperative ACS or AMI. The risk of postoperative stroke plateaued after a 20-month interval until surgery, irrespective of surgical urgency.

Conclusions: These observational data suggest increased adverse outcomes after a recent cardiovascular event can occur for up to 37 months after a major cardiovascular event.

Background: Managing postoperative pain in patients with obesity is challenging. Although multimodal analgesia has proved effective for pain relief, the specific impacts of different nonopioid i.v. analgesics and adjuvants on these patients are not well-defined. This study aims to assess the effectiveness of nonsteroidal antiinflammatory drugs, paracetamol, ketamine, α-2 adrenergic receptor agonists, lidocaine, magnesium, and oral gabapentinoids in reducing perioperative opioid consumption and, secondarily, in mitigating the occurrence of general and postoperative pulmonary complications (POPCs), nausea, vomiting, PACU length of stay (LOS), and hospital LOS among surgical patients with obesity.

Methods: A systematic review and network meta-analysis was performed. PubMed, Scopus, Web of Science, CINAHL, and EMBASE were searched. Only English-language RCTs investigating the use of nonopioid analgesics and adjuvants in adult surgical patients with obesity were included. The quality of evidence and certainty were assessed using the RoB 2 tool and GRADE framework, respectively.

Results: In total, 37 RCTs involving 3602 patients were included in the quantitative analysis. Compared with placebo/no intervention or a comparator, dexmedetomidine, ketamine, lidocaine, magnesium, and gabapentin significantly reduced postoperative opioid consumption after surgery. Ketamine/esketamine also significantly reduced POPCs. Ibuprofen, dexmedetomidine, and lidocaine significantly reduced postoperative nausea, whereas dexmedetomidine, either alone or combined with pregabalin, and lidocaine reduced postoperative vomiting. Dexmedetomidine significantly reduced PACU LOS, whereas both paracetamol and lidocaine reduced hospital LOS.

Conclusions: Intravenous nonopioid analgesics and adjuvants are crucial in multimodal anaesthesia, reducing opioid consumption and enhancing postoperative care in adult surgical patients with obesity.

Systematic review protocol: CRD42023399373 (PROSPERO).