Goal-directed therapy based on rScO2 monitoring in elderly patients with one-lung ventilation: a randomized trial on perioperative inflammation and postoperative delirium

The Role of Cytokines in Perioperative Neurocognitive Disorders: A Review in the Context of Anesthetic Care

Perioperative neurocognitive disorders (PNDs), including postoperative delirium, delayed neurocognitive recovery, and long-term postoperative neurocognitive disorders, present significant challenges for older patients undergoing surgery. Inflammation is a protective mechanism triggered in response to external pathogens or cellular damage. Historically, the central nervous system (CNS) was considered immunoprivileged due to the presence of the blood-brain barrier (BBB), which serves as a physical barrier preventing systemic inflammatory changes from influencing the CNS. However, aseptic surgical trauma is now recognized to induce localized inflammation at the surgical site, further exacerbated by the release of peripheral pro-inflammatory cytokines, which can compromise BBB integrity. This breakdown of the BBB facilitates the activation of microglia, initiating a cascade of neuroinflammatory responses that may contribute to the onset of PNDs. This review explores the mechanisms underlying neuroinflammation, with a particular focus on the pivotal role of cytokines in the pathogenesis of PNDs.

Efficacy of Cerebral Oxygen Saturation Monitoring for Perioperative Neurocognitive Disorder in Adult Noncardiac Surgical Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Perioperative neurocognitive disorders are common perioperative complications associated with various poor outcomes. Regional cerebral oxygen saturation (rSO2) monitoring is a noninvasive technique based on near-infrared spectroscopy detection. Due to the considerable controversy among currently published studies on the application of intraoperative rSO2 monitoring in adult patients undergoing elective noncardiac surgery, this study aims to conduct a systematic review and meta-analysis to provide more comprehensive and robust evidence to support clinical decision-making.

METHODS

This study conducted a systematic literature search of databases including PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science, from their inception to May 1, 2024. The eligible randomized controlled trials included adult patients undergoing elective noncardiac surgery under general anesthesia who received optimized anesthesia management guided by rSO2 monitoring and those in the control group who received routine anesthesia management under standard monitoring or blinded rSO2 monitoring. The primary outcomes were the incidence of perioperative neurocognitive disorders, including postoperative delirium (POD) and postoperative cognitive dysfunction (POCD), and Mini-Mental State Examination (MMSE) scores. Secondary outcomes included the incidence of intraoperative cerebral desaturation and length of hospital stay (LOS).

RESULTS

The pooled results showed that compared to the control group, optimized anesthesia management guided by intraoperative rSO2 monitoring significantly reduced the incidence of POCD within 7 days postoperatively and may reduce the incidence of POCD at 3 months and longer periods postoperatively. However, it may not reduce the incidence of POD within 7 days or longer periods postoperatively, improve MMSE scores, reduce the incidence of intraoperative cerebral desaturation, or shorten LOS. Given the substantial heterogeneity in the pooled results for MMSE scores within 7 days postoperatively and LOS, and the limited number of studies reporting the incidence of POD, POCD, and MMSE scores after 7 days postoperatively, the related results should be interpreted with caution.

CONCLUSIONS

Despite the presence of heterogeneity and the inclusion of a limited number of studies for some outcomes, it is still recommended that clinical anesthesiologists routinely perform intraoperative rSO2 monitoring and optimize intraoperative anesthesia management based on the monitoring results to maximize rSO2 and improve cerebral perfusion, thereby improving patients' neurocognitive outcomes. Further large-scale, high-quality studies are needed to confirm the conclusions of this study.

AI-Assisted Identification of Primary and Secondary Metabolomic Markers for Postoperative Delirium

Despite considerable investigative efforts, the molecular mechanisms of postoperative delirium (POD) remain unresolved. The present investigation employs innovative methodologies for identifying potential primary and secondary metabolic markers of POD by analyzing serum metabolomic profiles utilizing the genetic algorithm and artificial neural networks. The primary metabolomic markers constitute a combination of metabolites that optimally distinguish between POD and non-POD groups of patients. Our analysis revealed L-lactic acid, inositol, and methylcysteine as the most salient primary markers upon which the prediction accuracy of POD manifestation achieved AUC = 99%. The secondary metabolomic markers represent metabolites that exhibit perturbed correlational patterns within the POD group. We identified 54 metabolites as the secondary markers of POD, incorporating neurotransmitters such as gamma-aminobutyric acid (GABA) and serotonin. These findings imply a systemic disruption in metabolic processes in patients with POD. The deployment of gene network reconstruction techniques facilitated the postulation of hypotheses describing the role of established genomic POD markers in the molecular-genetic mechanisms of metabolic pathways dysregulation, and involving the identified primary and secondary metabolomic markers. This study not only expands the understanding of POD pathogenesis but also introduces a novel technology for the bioinformatic analysis of metabolomic data that could aid in uncovering potential primary and secondary markers in diverse research domains.

Effect of optimizing cerebral oxygen saturation on postoperative delirium in older patients undergoing one-lung ventilation for thoracoscopic surgery

OBJECTIVES

This randomized controlled trial investigated whether the regional cerebral oxygenation saturation (rScO2)-guided lung-protective ventilation strategy could improve brain oxygen and reduce the incidence of postoperative delirium (POD) in patients older than 65 years.

METHODS

This randomized controlled trial enrolled 120 patients undergoing thoracic surgery who received one-lung ventilation (OLV). Patients were randomly assigned to the lung-protective ventilation group (PV group) or rScO2-oriented lung-protective ventilation group (TPV group). rScO2 was recorded during the surgery, and the occurrence of POD was assessed.

RESULTS

The incidence of POD 3 days after surgery-the primary outcome-was significantly lower in the TPV group (23.3% versus 8.5%). Meanwhile, the levels of POD-related biological indicators (S100β, neuron-specific enolase, tumor necrosis factor-α) were lower in the TPV group. Considering the secondary outcomes, both groups exhibited a lower oxygenation index after OLV, whereas partial pressure of carbon dioxide and mean arterial pressure were significantly increased in the TPV group. In addition, minimum rScO2 during surgery and mean rScO2 were higher in the TPV group than in the PV group.

CONCLUSION

Continuous intraoperative monitoring of brain tissue oxygenation and active intervention measures guided by cerebral oxygen saturation are critical for improving brain metabolism and reducing the risk of POD.

Characteristics associated with effectiveness in postoperative delirium research: a systematic review of randomised controlled trials with meta-regression and meta-analysis

BACKGROUND

Postoperative delirium remains prevalent despite extensive research through randomised trials aimed at reducing its incidence. Understanding trial characteristics associated with interventions' effectiveness facilitates data interpretation.

METHODS

Trial characteristics were extracted from eligible trials identified through two systematic literature searches. Multivariable meta-regression was used to investigate trial characteristics associated with effectiveness estimated using odds ratios. Meta-analysis was used to investigate pooled effectiveness.

RESULTS

We identified 201 eligible trials. Compared with China, trials from the USA/Canada (ratio of odds ratio, 1.89; 95% confidence interval, 1.45-2.45) and Europe/Australia/New Zealand (1.67; 1.29-2.18) had an 89% and 67% higher odds ratio, respectively, suggesting reduced effectiveness. The effectiveness was enhanced when the incidence of postoperative delirium increased (0.85; 0.79-0.92, per 10% increase). Trials with concerns related to deviations from intended interventions reported increased effectiveness compared with those at low risk (0.69; 0.53-0.90). Compared with usual care, certain interventions appeared to have reduced the incidence of postoperative delirium in low-risk trials with low-to-moderate certainty of evidence. However, these findings should be considered inconclusive because of challenges in grouping heterogeneous interventions, the limited number of eligible trials, the prevalence of small-scale studies, and potential publication bias.

CONCLUSIONS

The effectiveness of postoperative delirium trials varied based on the region of trial origin, the incidence of delirium, and the risk of bias. The limitations caution against drawing definitive conclusions from different bodies of evidence. These findings highlight the imperative need to improve the quality of research on a global scale.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023413984).

The Effect of Ciprofol on Postoperative Delirium in Elderly Patients Undergoing Thoracoscopic Surgery for Lung Cancer: A Prospective, Randomized, Controlled Trial

Purpose

This study was conducted to assess whether ciprofol vs propofol could affect the incidence of postoperative delirium (POD) in elderly patients with lung cancer after thoracoscopic surgery.

Patients and Methods

In this study, a total of 84 elderly patients undergoing thoracoscopic surgery for lung cancer were recruited and randomized into two groups to receive anesthesia with either ciprofol or propofol. The primary outcome was the incidence of POD within three days after surgery. Secondary outcomes included the Confusion Assessment Method (CAM) score, intraoperative indicators related to mean arterial pressure (MAP), and cerebral tissue oxygen saturation (SctO2). Moreover, MAP- and SctO2-related indicators associated with POD were analyzed.

Results

The incidence of POD was 7.1% and 16.7%, respectively, in the ciprofol group and the propofol group (risk ratio [RR], 0.37; 95% confidence interval [CI], 0.07 to 2.03; risk difference [RD], -9.6%; 95% CI, -23.3% to 4.1%; p = 0.178). Compared with those in the propofol group, patients in the ciprofol group had lower CAM scores three days after surgery (13 (12, 15) vs 15 (14, 17); 12 (11, 13) vs 14 (13, 16); 12 (11, 12) vs 13 (12, 14), p<0.05). Besides, patients in the ciprofol group exhibited higher mean and minimum MAP (88.63 ± 6.7 vs 85 ± 8.3; 69.81 ± 9.59 vs 64.9 ± 9.43, p<0.05) and SctO2 (77.26 ± 3.96 vs 75.3 ± 4.49, 71.69 ± 4.51 vs 68.77 ± 6.46, p<0.05) and percentage of time for blood pressure stabilization (0.6 ± 0.14 vs 0.45 ± 0.14, p<0.05) than those in the propofol group. Furthermore, MAP and SctO2-related indicators were validated to correlate with POD.

Conclusion

Anesthesia with ciprofol did not increase the incidence of POD compared with propofol. The results demonstrated that ciprofol could improve intraoperative MAP and SctO2 levels and diminish postoperative CAM scores.

The Impact of Regional Nerve Blocks on Postoperative Delirium or Cognitive Dysfunction following Thoracic Surgery: A Systematic Review and Meta-Analysis

Regional nerve blocks (NBs) mitigate the occurrence of postoperative cognitive dysfunction (POCD) and postoperative delirium (POD) in adult patients undergoing thoracic surgery. This study aimed to determine the exact effect of NBs on POCD and POD. Electronic databases, including PubMed, EMBASE, CINAHL, Scopus, and Web of Science, were searched for studies. The primary outcome was the incidence of POD or POCD. The secondary outcome was pain scores assessed 24 and 48 h postoperatively. We calculated the log odds ratio (LOR) and standardized mean difference (SMD) with 95% confidence intervals (CIs). The LOR was converted to an odds ratio (OR). In the analysis of 1010 patients from seven randomized controlled trials, POD and POCD rates were 14.1% and 16.7%, respectively, in the NB group, and higher, at 27.3% and 35.2%, in the control group. NBs reduced the incidence of POD (OR, 0.44; 95%CI 0.30 to 0.64; p < 0.001; I2 = 0.00%) and POCD (OR, 0.43; 95%CI 0.24 to 0.76; p < 0.001; I2 = 0.00%). NBs reduced pain scores at 24 h (SMD, -2.60; 95%CI -3.90 to -1.30, p < 0.001; I2 = 97.68%) and 48 h (SMD, -1.80; 95%CI -3.18 to -0.41, p = 0.01; I2 = 98.14%) postoperatively. NBs mitigated the occurrence of POD and POCD in adult patients after thoracic surgery.

Effect of intravenous low-dose norepinephrine on blood loss in non-tourniquet total knee arthroplasty under general anesthesia: a randomized, double-blind, controlled, single-center trial

OBJECTIVE

This prospective trial aimed to evaluate the effects of low-dose intravenous norepinephrine (NE) on intraoperative blood loss and bleeding from osteotomy sites during non-tourniquet total knee arthroplasty (TKA) under general anesthesia.

METHODS

A total of 120 patients who underwent TKA between December 2020 and May 2022 were enrolled and randomly assigned to the intravenous low-dose NE Group (NE Group) or the control group (C Group). During surgery, NE Group received 0.05-0.1 μg/(kg min) of NE intravenously to raise and maintain the patient's mean arterial pressure (MAP). C Group received the same dose of saline as placebo. Intraoperative blood loss, bleeding score at osteotomy sites, Δlactate levels (Lac), postoperative complications, and transfusion rate during hospitalization were compared between groups.

RESULTS

Intraoperative and osteotomy blood loss was significantly lower in the NE Group than in the C Group (P < 0.001). No significant difference was observed in ΔLac between groups (P > 0.05). There was no significant difference in complications between the groups 3 days after surgery (P > 0.05). In addition, there was no significant difference in blood transfusion rates between the two groups during hospitalization (P > 0.05).

CONCLUSION

In non-tourniquet TKA under general anesthesia, low-dose intravenous NE safely and effectively reduced intraoperative blood loss and provided a satisfactory osteotomy site while maintaining a higher MAP.

Implication of age-related changes on anesthesia management

Elderly patients have a high risk of perioperative morbidity and mortality. Pluri-morbidities, polypharmacy, and functional dependence may have a great impact on intraoperative management and request specific cautions. In addition to surgical stress, several perioperative noxious stimuli such as fasting, blood loss, postoperative pain, nausea and vomiting, drug adverse reactions, and immobility may trigger a derangement leading to perioperative complications. Older patients have a high risk of major hemodynamic derangement due to aging of the cardiovascular system and associated comorbidities. The hemodynamic monitoring as well as fluid therapy should be the most accurate as possible. Aging is accompanied by decreased renal function, which is related to a reduction in renal blood flow, renal mass, and the number and size of functioning nephrons. Drugs eliminated predominantly by the renal route need dosage adjustments based on residual renal function. Liver mass, hepatic blood flow, and intrinsic metabolic activity are decreased in the elderly, and all drugs metabolized by the liver have a variable half-life, thus requiring dose reduction. Decreased neural plasticity contributes to a high risk for postoperative delirium. Monitoring of anesthesia depth should be mandatory to avoid overdosage of hypnotic drugs. Prevention of postoperative pulmonary complications requires both protective ventilation strategies and adequate recovery of neuromuscular function at the end of surgery. Avoidance of hypothermia cannot be missed. The aim of this review is to describe comprehensive strategies for intraoperative management plans tailored to meet the unique needs of elderly surgical patients, thus improving outcomes in this vulnerable population.

Effect of perioperative goal-directed fluid therapy on postoperative complications after thoracic surgery with one-lung ventilation: a systematic review and meta-analysis

BACKGROUND

An understanding of the impact of goal-directed fluid therapy (GDFT) on the outcomes of patients undergoing one-lung ventilation (OLV) for thoracic surgery remains incomplete and controversial. This meta-analysis aimed to assess the effect of GDFT compared to other fluid therapy strategies on the incidence of postoperative complications in patients with OLV.

METHODS

The Embase, Cochrane Library, Web of Science, and MEDLINE via PubMed databases were searched from their inception to November 30, 2022. Forest plots were constructed to present the results of the meta-analysis. The quality of the included studies was evaluated using the Cochrane Collaboration tool and Risk Of Bias In Non-Randomized Study of Interventions (ROBINS-I). The primary outcome was the incidence of postoperative complications. Secondary outcomes were the length of hospital stay, PaO2/FiO2 ratio, total fluid infusion, inflammatory factors (TNF-α, IL-6), and postoperative bowel function recovery time.

RESULTS

A total of 1318 patients from 11 studies were included in this review. The GDFT group had a lower incidence of postoperative complications [odds ratio (OR), 0.47; 95% confidence interval (95% CI), 0.29-0.75; P = 0.002; I 2, 67%], postoperative pulmonary complications (OR 0.48, 95% CI 0.27-0.83; P = 0.009), and postoperative anastomotic leakage (OR 0.51, 95% CI 0.27-0.97; P = 0.04). The GDFT strategy reduces total fluid infusion.

CONCLUSIONS

GDFT is associated with lower postoperative complications and better survival outcomes after thoracic surgery for OLV.