The effect of lidocaine on early postoperative cognitive dysfunction after coronary artery bypass surgery

Postoperative cognitive dysfunction: Review of pathophysiology, diagnostics and preventive strategies

Postoperative cognitive impairment is a common disorder after major surgery. Advances in medicine and treatment have resulted in an increasingly ageing population undergoing major surgical procedures. Since age is the most important risk factor for postoperative cognitive decline, it is not surprising that impairment of cognitive functions after surgery was recorded in almost a third of elderly patients. Postoperative cognitive dysfunction is part of the spectrum of postoperative cognitive impairment and researchers often confuse it with postoperative delirium and delayed neurocognitive recovery. This is the cause of great differences in the results of research that is focused on the incidence and possible prevention of postoperative cognitive dysfunction. In this review, we focused on current recommendations for a uniform nomenclature of postoperative cognitive impairment and diagnosis of postoperative cognitive dysfunction, the presumed pathophysiology of postoperative cognitive dysfunction and recommendations for its treatment and possible prevention strategies.

Postoperative cognitive dysfunction-current research progress

Postoperative cognitive dysfunction (POCD) commonly occurs after surgery, particularly in elderly individuals. It is characterized by a notable decline in cognitive performance, encompassing memory, attention, coordination, orientation, verbal fluency, and executive function. This reduction in cognitive abilities contributes to extended hospital stays and heightened mortality. The prevalence of POCD can reach 40% within 1 week following cardiovascular surgery and remains as high as 17% 3 months post-surgery. Furthermore, POCD exacerbates the long-term risk of Alzheimer's disease (AD). As a result, numerous studies have been conducted to investigate the molecular mechanisms underlying POCD and potential preventive strategies. This article provides a review of the research progress on POCD.

Hypothermic Circulatory Arrest in Adult Aortic Arch Surgery: A Review of Hypothermic Circulatory Arrest and its Anesthetic Implications

Diseases affecting the aortic arch often require surgical intervention. Hypothermic circulatory arrest (HCA) enables a safe approach during open aortic arch surgeries. Additionally, HCA provides neuroprotection by reducing cerebral metabolism and oxygen requirements. However, HCA comes with significant risks (eg, neurologic dysfunction, stroke, and coagulopathy), and the cardiac anesthesiologist must completely understand the surgical techniques, possible complications, and management strategies.

The effect of intravenous lidocaine on postoperative cognitive dysfunction: a systematic review and meta-analysis

BACKGROUND

Postoperative cognitive dysfunction (POCD) has been reported as a significant complication in elderly patients. Various methods have been proposed for reducing the incidence and severity of POCD. Intravenous lidocaine administration has been reported in the literature to reduce POCD, but the effect of lidocaine remains controversial.

METHODS

We screened Medline, Embase, Cochrane Library, and China National Knowledge Infrastructure (up to April 2022) databases following a search strategy for intravenous lidocaine on POCD. We also screened related bibliographies on lidocaine for POCD. Ten articles comprising 1517 patients were selected and analyzed. We divided the postoperative follow-up period as follows: short term (<30 days), medium term (30-90 days), and long term (>90 days).

OUTCOMES

We found that lidocaine could attenuate the overall incidence of POCD, especially in the short term. There were no differences between lidocaine and placebo on the overall severity of POCD.

CONCLUSION

Lidocaine administered intravenously could attenuate the overall incidence of POCD and its severity in the short term.

The effect of melatonin on cognitive functions following coronary artery bypass grafting: A triple-blind randomized-controlled trial

Background

Cognitive dysfunction presents one of the chief causes of postoperative morbidity. Melatonin as a neurohormone can improve neurocognitive functioning and sleep disorders. We evaluated the effect of melatonin on the postoperative cognitive function of patients undergoing coronary artery bypass grafting (CABG).

Materials and Methods

A triple-blind randomized-controlled trial was conducted on 66 CABG candidates in Namazee Hospital (Shiraz, Iran). Patients were assigned equally into two groups receiving melatonin 10 mg or a placebo daily for 4 weeks before surgery and 2 days after surgery in the intensive care unit. The Mini-Mental State Examination (MMSE), Tower of London (ToL), and Wechsler Adults Intelligence Scale-Revised (WAIS-R) cognitive function tests were performed in both groups 4 weeks before surgery (time point 1), 2 days after surgery (time point 2), and 6 weeks after initial administration of melatonin (time point 3).

Results

The mean change score (time point 3-time point 1) differed significantly between the two groups in the MMSE (P ≤ 0.001), ToL total score (P = 0.001), and WAIS-R general IQ (P ≤ 0.001), picture completion (P ≤ 0.001), vocabulary (P = 0.024), and digit span (P = 0.01). On the other hand, no significant differences were detected in the WAIS-R block design, ToL total time delay, ToL total lab, and ToL total result scores.

Conclusion

The MMSE and WAIS-R tests revealed that melatonin might have prophylactic effects against postoperative cognitive disturbance in patients undergoing elective CABG.

Prophylactic effect of intravenous lidocaine against cognitive deficit after cardiac surgery: A PRISMA-compliant meta-analysis and trial sequential analysis

BACKGROUND

This study aimed at providing an updated evidence of the association between intraoperative lidocaine and risk of postcardiac surgery cognitive deficit.

METHODS

Randomized clinical trials (RCTs) investigating effects of intravenous lidocaine against cognitive deficit in adults undergoing cardiac surgeries were retrieved from the EMBASE, MEDLINE, Google scholar, and Cochrane controlled trials register databases from inception till May 2021. Risk of cognitive deficit was the primary endpoint, while secondary endpoints were length of stay (LOS) in intensive care unit/hospital. Impact of individual studies and cumulative evidence reliability were evaluated with sensitivity analyses and trial sequential analysis, respectively.

RESULTS

Six RCTs involving 963 patients published from 1999 to 2019 were included. In early postoperative period (i.e., 2 weeks), the use of intravenous lidocaine (overall incidence = 14.8%) was associated with a lower risk of cognitive deficit compared to that with placebo (overall incidence = 33.1%) (relative risk = 0.49, 95% confidence interval: 0.32-0.75). However, sensitivity analysis and trial sequential analysis signified insufficient evidence to arrive at a firm conclusion. In the late postoperative period (i.e., 6-10 weeks), perioperative intravenous lidocaine (overall incidence = 37.9%) did not reduce the risk of cognitive deficit (relative risk = 0.99, 95% confidence interval: 0.84) compared to the placebo (overall incidence = 38.6%). Intravenous lidocaine was associated with a shortened LOS in intensive care unit/hospital with weak evidence.

CONCLUSION

Our results indicated a prophylactic effect of intravenous lidocaine against cognitive deficit only at the early postoperative period despite insufficient evidence. Further large-scale studies are warranted to assess its use for the prevention of cognitive deficit and enhancement of recovery (e.g., LOS).

Efficacy of systemic lidocaine in postoperative delirium in elderly patients undergoing laparoscopic colorectal surgery: study protocol for a multicentre, prospective, double-blind, randomised, parallel-group, superiority, placebo-controlled trial

INTRODUCTION

Systemic lidocaine may reduce pain intensity and accelerate postoperative recovery. However, the efficacy of systemic lidocaine in cognitive function has not been established. This study protocol is designed to clarify the effectiveness of lidocaine in postoperative delirium (POD) in elderly patients scheduled for elective laparoscopic colorectal surgery.

METHODS AND ANALYSIS

This is a prospective, multicentre, randomised, double-blind, parallel-group, placebo-controlled trial. One thousand and twenty elderly patients will be randomly allocated in a ratio of 1:1 to receive either systemic lidocaine (a bolus of 1.5 mg/kg, followed by an infusion of 1.5 mg/kg/hour until the end of the surgery) or identical volumes and rates of 0.9% saline. The primary outcome measure is the prevalence of POD during the first 5 postoperative days. Secondary outcomes include emergence agitation, the area under the curve of the Numeric Rating Scale pain scores over 48 hours, postoperative 48-hour cumulative opioid consumption, postoperative nausea and vomiting (PONV), recovery of bowel function, quality of recovery, and patient satisfaction with postoperative analgesia.

ETHICS AND DISSEMINATION

The Ethical Committee of the Fujian Provincial Hospital approved the study protocol (ref: K2021-06-018). Other participating subcentres must also obtain ethics committee approval before the start of the study. We will obtain written informed consent from each patient before they are randomised. This study will be presented at scientific conferences and submitted to international journals.

TRIAL REGISTRATION NUMBER

ChiCTR2100050314.

Targeted temperature management in cardiac surgery: a systematic review and meta-analysis on postoperative cognitive outcomes

BACKGROUND

Postoperative cognitive decline occurs commonly after cardiac surgery. The available literature is inconclusive on the role of intraoperative causal or protective factors.

METHODS

We systematically reviewed studies evaluating delayed neurocognitive recovery (DNR), postoperative neurocognitive disorder (NCD), stroke, and the mortality rates among patients undergoing hypothermic or normothermic cardiopulmonary bypass (CPB). We further performed a subgroup analysis for age, surgery type (coronary artery bypass grafting [CABG], valve surgery, or combined), and the mean arterial blood pressure (MAP) during CPB, and conducted a proportion meta-analysis after calculation of single proportions and confidence intervals (CIs).

RESULTS

We included a total of 58 studies with 9609 patients in our analysis. Among these, 1906 of 4010 patients (47.5%) had DNR, and 2071 of 7160 (28.9%) had postoperative NCD. Ninety of 4625 patients (2.0%) had a stroke, and 174 of 7589 (2.3%) died. There was no statistically significant relationship between the considered variables and DNR, NCD, stroke, and mortality. In the subgroup analysis comparing hypothermic with normothermic CPB, we found higher NCD rates after combined surgery; for normothermic CPB cases only, the rates of DNR and NCD were lower after combined surgery compared with CABG surgery. A MAP >70 mm Hg compared with MAP=50-70 mm Hg during CPB was associated with a lower rate of DNR.

CONCLUSIONS

Temperature, MAP during cardiopulmonary bypass age, and surgery type were not associated with neurocognitive disorders, stroke, and mortality in cardiac surgery. Normothermic cardiopulmonary bypass, particularly when performed with MAP >70 mm Hg, may reduce the risk of postoperative neurocognitive decline after cardiac surgery.

PROSPERO REGISTRATION NUMBER

CRD42019140844.

Efficacy of a glucagon-like peptide-1 agonist and restrictive versus liberal oxygen supply in patients undergoing coronary artery bypass grafting or aortic valve replacement: study protocol for a 2-by-2 factorial designed, randomised clinical trial

INTRODUCTION

Coronary artery bypass grafting (CABG) and/or aortic valve replacement (AVR) are associated with risk of death, as well as brain, heart and kidney injury. Glucagon-like peptide-1 (GLP-1) analogues are approved for treatment of type 2 diabetes, and GLP-1 analogues have been suggested to have potential organ-protective and anti-inflammatory effects. During cardiopulmonary bypass (CPB), consensus on the optimal fraction of oxygen is lacking. The objective of this study is to determine the efficacy of the GLP-1-analogue exenatide versus placebo and restrictive oxygenation (50% fractional inspired oxygen, FiO2) versus liberal oxygenation (100% FiO2) in patients undergoing open heart surgery.

METHODS AND ANALYSIS

A randomised, placebo-controlled, double blind (for the exenatide intervention)/single blind (for the oxygenation strategy), 2×2 factorial designed single-centre trial on adult patients undergoing elective or subacute CABG and/or surgical AVR. Patients will be randomised in a 1:1 and 1:1 ratio to a 6-hour and 15 min infusion of 17.4 µg of exenatide or placebo during CPB and to a FiO2 of 50% or 100% during and after weaning from CPB. Patients will be followed until 12 months after inclusion of the last participant. The primary composite endpoint consists of time to first event of death, renal failure requiring renal replacement therapy, hospitalisation for stroke or heart failure. In addition, the trial will include predefined sub-studies applying more advanced measures of cardiac- and pulmonary dysfunction, renal dysfunction and cerebral dysfunction. The trial is event driven and aims at 323 primary endpoints with a projected inclusion of 1400 patients.

ETHICS AND DISSEMINATION

Eligible patients will provide informed, written consent prior to randomisation. The trial is approved by the local ethics committee and is conducted in accordance with Danish legislation and the Declaration of Helsinki. The results will be presented in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02673931.

Association between perioperative intravenous lidocaine and subjective quality of recovery: A meta-analysis of randomized controlled trials

STUDY OBJECTIVE

To evaluate the impact of perioperative intravenous lidocaine on the quality of recovery (QoR) following surgery.

DESIGN

Meta-analysis of randomized controlled trials (RCTs).

SETTING

Postoperative care.

INTERVENTION

Intravenous lidocaine during perioperative period.

PATIENTS

Adults undergoing surgery under general anesthesia.

MEASUREMENTS

The primary outcome was postoperative QoR measured with QoR-40 questionnaire, while the secondary outcomes included five individual dimensions (i.e., emotional, state, physical comfort, psychological support, physical independence, and pain) of QoR-40, intraoperative opioid consumption, and risk of chronic postsurgical pain (CPSP).

MAIN RESULTS

Medline, Cochrane Library, Google scholar, and EMBASE databases were searched from inception to June 2021. Fourteen RCTs involving 1148 patients in total undergoing elective surgery published from 2012 to 2021 were included. QoR-40 scores were evaluated at postoperative 24 h (12 trials), 72 h (one trial), and Day 5 (one trial), respectively. Pooled results revealed significantly higher global [mean difference (MD) = 9.65, 95% confidence interval (CI): 6.33 to 12.97; I² = 97%; 13 RCTs; n = 1085] and individual dimension QoR-40 scores in the lidocaine group than those in placebo group. Subgroup analysis demonstrated no significant impact of the type of surgery, age, gender, surgical time, anesthetic technique, lidocaine dosage, and time of assessment on global QoR-40 scores. The use of intravenous lidocaine was associated with a significant reduction in intraoperative remifentanil consumption compared with that in the placebo group (standardized MD = -0.91, 95%CI: -1.32 to -0.51; I² = 86%; 10 RCTs; n = 799). There was no difference in risk of CPSP between the two groups [relative risk (RR) = 0.65, 95%CI: 0.33 to 1.25; I² = 58%; 4 RCTs; n = 309].

CONCLUSION

Our results verified the efficacy of intravenous lidocaine for enhancing postoperative quality of recovery by using a validated subjective tool and reducing intraoperative remifentanil consumption in patients receiving elective surgery under general anesthesia. Further studies are warranted to verify its efficacy in the acute care setting.

Ligustilide enhances hippocampal neural stem cells activation to restore cognitive function in the context of postoperative cognitive dysfunction

Ligustilide exerts potential neuroprotective effects against various cerebral ischaemic insults and neurodegenerative disorders. However, the function and mechanisms of LIG-mediated hippocampal neural stem cells (H-NSCs) activation as well as cognitive recovery in the context of post-operative cognitive dysfunction (POCD) remain elusive and need to be explored. Mice were subjected to transient global cerebral ischaemia and reperfusion (tGCI/R) injury and treated with LIG (80 mg/kg) or vehicle for 1 month. Morris water maze test and western blot were employed to assess cognitive function. Nissl staining and immunofluorescence (IF) staining were used to detect H-NSCs proliferation and neurogenesis in hippocampus. Subsequently, primary H-NSCs were treated with LIG, and the level of H-NSCs proliferation and neuronal-differentiation was examined by IF staining for Edu and β-Tubulin III. The protein levels of ERK1/2, β-catenin, NICD, TLR4, Akt and FoxO1 were examined using western blotting. Finally, pretreatment with the ERK agonist SCH772984 was performed to observe the change in ERK expression. LIG treatment promoted H-NSCs proliferation and neurogenesis, increased the number of neurons in the hippocampal subfields, and ultimately reversed cognitive impairment in tGCI/R injury. Furthermore, LIG also promoted primary H-NSCs proliferation and neuronal-differentiation, as well as ERK1/2 phosphorylation. Pretreatment with SCH772984 effectively reversed the ability of LIG to induce ERK1/2 phosphorylation and promote H-NSCs proliferation and neuronal-differentiation. LIG can promote cognitive recovery after tGCI/R injury by activating ERK1/2 in H-NSCs to promote their proliferation and neurogenesis in the hippocampus. Therefore, LIG has potential for use in the prevention and/or treatment of POCD.

Pharmacological Conditioning of the Heart: An Update on Experimental Developments and Clinical Implications

The aim of pharmacological conditioning is to protect the heart against myocardial ischemia-reperfusion (I/R) injury and its consequences. There is extensive literature that reports a multitude of different cardioprotective signaling molecules and mechanisms in diverse experimental protocols. Several pharmacological agents have been evaluated in terms of myocardial I/R injury. While results from experimental studies are immensely encouraging, translation into the clinical setting remains unsatisfactory. This narrative review wants to focus on two aspects: (1) give a comprehensive update on new developments of pharmacological conditioning in the experimental setting concentrating on recent literature of the last two years and (2) briefly summarize clinical evidence of these cardioprotective substances in the perioperative setting highlighting their clinical implications. By directly opposing each pharmacological agent regarding its recent experimental knowledge and most important available clinical data, a clear overview is given demonstrating the remaining gap between basic research and clinical practice. Finally, future perspectives are given on how we might overcome the limited translatability in the field of pharmacological conditioning.

Intravenous Infusion of Lidocaine Can Accelerate Postoperative Early Recovery in Patients Undergoing Surgery for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is defined by intermittent and recurrent episodes of partial or complete obstruction of the upper airway during sleep. Intermittent and recurrent hypoxia/reoxygenation is the main pathophysiological mechanism of OSA. Its consequences include systemic inflammation, activation of the sympathetic nervous system, and release of oxygen free radicals. Infusion of intravenous (IV) lidocaine has anti-inflammatory, antihyperalgesic, and analgesic properties, supporting its use as an anesthetic adjuvant. Lidocaine can reduce nociception and/or cardiovascular responses to surgical stress, as well as postoperative pain and/or analgesic requirements. Because of the high prevalence of OSA in obese patients, the use of opioids to manage postoperative pain in that population is often accompanied by the development of adverse respiratory events, such as hypoventilation and hypoxemia. IV infusion of lidocaine has been shown to enhance the quality of early recovery after laparoscopic bariatric and upper airway surgery. However, limited evidence exists regarding its use in patients undergoing surgery for OSA. In addition, whether IV infusion of lidocaine can improve postoperative early recovery in patients undergoing surgery for OSA remains unknown. Therefore, we hypothesized that IV infusion of lidocaine can improve postoperative early recovery in patients undergoing surgery for OSA. Perioperative infusion also may be a promising analgesic adjunct to enhanced recovery after surgery (ERAS) protocols.

Mechanisms of Action by Which Local Anesthetics Reduce Cancer Recurrence: A Systematic Review

BACKGROUND

Surgery in concert with anesthesia is a key part of the management of advanced-stage cancers. Anesthetic agents such as opioids and volatile anesthetics have been shown to promote recurrence in preclinical models, whereas some animal models have shown that the use of lidocaine may be beneficial in reducing cancer recurrence. The purpose of this article is to review the current literature to highlight the mechanisms of action by which local anesthetics are thought to reduce cancer recurrence.

METHODS

A systematic review was conducted using the PubMed (1966 to 2018) electronic database. Search terms included "lidocaine," "ropivicaine," "procaine," "bupivicaine," "mepivicaine," "metastasis," "cancer recurrence," "angiogenesis," and "local anesthetics" in various combinations. The search yielded 146 total abstracts for initial review, 20 of which met criteria for inclusion. Theories for lidocaine's effect on cancer recurrence were recorded. All studies were reviewed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist.

RESULTS

Numerous mechanisms were proposed based on the local anesthetic used and the type of cancer. Mechanisms include those that are centered on endothelial growth factor receptor, voltage-gated sodium and calcium channels, transient receptor melanoplastin 7, hyperthermia, cell cycle, and demyelination.

CONCLUSIONS

In vivo models suggest that local anesthetic administration leads to reduced cancer recurrence. The etiology of this effect is likely multifactorial through both inhibition of certain pathways and direct induction of apoptosis, a decrease in tumor migration, and an association with cell cycle-mediated and DNA-mediated effects. Additional research is required to further define the clinical implications.

Pharmacological Agents That Prevent Postoperative Cognitive Dysfunction in Patients With General Anesthesia: A Network Meta-analysis

BACKGROUND

Postoperative cognitive dysfunction (POCD) is associated with prolonged hospital stays, increased mortality, and negative socioeconomic consequences. Dexmedetomidine, ketamine, dexamethasone, and lidocaine have previously been reported to be effective for preventing POCD.

STUDY QUESTION

In this network meta-analysis, we apply direct and indirect comparisons to rank these pharmacological agents in terms of their effect on POCD, through which we seek to provide evidence for future clinical medication.

DATA SOURCES

A comprehensive literature search of PubMed, EMBASE, the Cochrane Library, and Web of Science was conducted to identify randomized controlled trials that examined the effects of dexmedetomidine, ketamine, dexamethasone, or lidocaine on POCD induced by general anesthesia.

STUDY DESIGN

For eligible studies, 2 reviewers independently extracted data and assessed the respective risk of bias. Bayesian network meta-analysis was conducted using R-3.4.1 software. A total of 30 articles were included in this meta-analysis.

RESULTS

Direct comparison showed that dexmedetomidine [odds ratio (OR) = 0.42, 95% confidence interval (CI): 0.32-0.55] may decrease the incidence of POCD for noncardiac surgery; dexmedetomidine (OR = 0.08, 95% CI: 0.01-0.63) and ketamine (OR = 0.09, 95% CI: 0.02-0.32) were found to decrease POCD for cardiac surgery. The R-software ranking result for prevention of POCD was dexmedetomidine, lidocaine, ketamine, placebo, and dexamethasone, respectively, in noncardiac surgery, and dexmedetomidine, ketamine, lidocaine, placebo, and dexamethasone in cardiac surgery.

CONCLUSION

Dexmedetomidine exhibited obvious superiority to other agents for noncardiac surgery; dexmedetomidine and ketamine exhibited a significantly better performance than other agents for cardiac surgery. Dexamethasone did not show better efficacy than the placebo. However, more rigorously designed studies comprising larger sample sizes are needed to confirm our findings.

Lidocaine promotes autophagy of SH-SY5Y cells through inhibiting PI3K/AKT/mTOR pathway by upregulating miR-145

Lidocaine is one of the most common local anesthetics (LA) used in clinical practice and it is neurotoxic. Recent studies suggested that LA, including lidocaine, could exert protective effect over neurotoxicity by promoting autophagy. However, the underlying mechanism was not sufficiently elucidated. This study aimed to explore the mechanism behind. Human neuroblastoma cell line SH-SY5Y was used throughout the whole study. The effect of lidocaine on viability, toxicity of SH-SY5Y cells were analyzed by MTT and lactate dehydrogenase (LDH) assays, respectively. The relative expression of miR-145 was assessed by quantitative reverse transcription-polymerase chain reaction. The impact which lidocaine brought on PI3K/AKT/mTOR pathway and autophagy-related proteins were examined by the western blot assay. LC3B was assessed by immunofluorescence staining. The interaction between miR-145 and AKT3 was conducted by the dual-luciferase reporting assay. Lidocaine inhibited viability of SH-SY5Y cells in a time and dose dependent manner and enhanced the release of LDH in SH-SY5Y cells. Furthermore, the expression of miR-145 and autophagy were enhanced by lidocaine. Transfection with miR-145 inhibitor inhibited the release of LDH and autophagy. miR-145 targeted AKT3 to inhibit PI3K/AKT/mTOR pathway. Finally, lidocaine inactivated PI3K/AKT/mTOR pathways via upregulation of miR-145, and it subsequently promoted autophagy of SH-SY5Y cells. However, silence of miR-145 could reverse the promotion of the autophagy of SH-SY5Y cells. Our results showed that lidocaine promoted autophagy of nerve cells via regulating miR-145 expression and further inactivation of PI3K/AKT/mTOR signaling pathway.

Intravenous Lidocaine Does Not Improve Neurologic Outcomes after Cardiac Surgery: A Randomized Controlled Trial

BACKGROUND

Cognitive decline after cardiac surgery occurs frequently and persists in a significant proportion of patients. Preclinical studies and human trials suggest that intravenous lidocaine may confer protection in the setting of neurologic injury. It was hypothesized that lidocaine administration would reduce cognitive decline after cardiac surgery compared to placebo.

METHODS

After institutional review board approval, 478 patients undergoing cardiac surgery were enrolled into this multicenter, prospective, randomized, double-blinded, placebo-controlled, parallel group trial. Subjects were randomized to lidocaine 1 mg/kg bolus after the induction of anesthesia followed by a continuous infusion (48 μg · kg · min for the first hour, 24 μg · kg · min for the second hour, and 10 μg · kg · min for the next 46 h) or saline with identical volume and rate changes to preserve blinding. Cognitive function was assessed preoperatively and at 6 weeks and 1 yr postoperatively using a standard neurocognitive test battery. The primary outcome was change in cognitive function between baseline and 6 weeks postoperatively, adjusting for age, years of education, baseline cognition, race, and procedure type.

RESULTS

Among the 420 allocated subjects who returned for 6-week follow-up (lidocaine: N = 211; placebo: N = 209), there was no difference in the continuous cognitive score change (adjusted mean difference [95% CI], 0.02 (-0.05, 0.08); P = 0.626). Cognitive deficit (greater than 1 SD decline in at least one cognitive domain) at 6 weeks occurred in 41% (87 of 211) in the lidocaine group versus 40% (83 of 209) in the placebo group (adjusted odds ratio [95% CI], 0.94 [0.63, 1.41]; P = 0.766). There were no differences in any quality of life outcomes between treatment groups. At the 1-yr follow-up, there continued to be no difference in cognitive score change, cognitive deficit, or quality of life.

CONCLUSIONS

Intravenous lidocaine administered during and after cardiac surgery did not reduce postoperative cognitive decline at 6 weeks.

Evaluation of intravenous lidocaine in head and neck cancer surgery: study protocol for a randomized controlled trial

BACKGROUND

Pain after major head and neck cancer surgery is underestimated and has both nociceptive and neuropathic characteristics. Extended resection, flap coverage, nerve lesions, inflammation, and high-dose opioid administration can also lead to hyperalgesia and chronic postoperative pain. Opioids are frequently associated with adverse events such as dizziness, drowsiness, nausea and vomiting, or constipation disturbing postoperative recovery and extending the length of hospital stay. Patients eligible for major head and neck cancer surgery cannot benefit from full multimodal pain management with locoregional anesthesia. Intravenous lidocaine, investigated in several studies, has been found to decrease acute pain and morphine consumption. Some data suggest also that it can prevent chronic postsurgical pain. Evidence supporting its use varies between surgical procedures, and there is no published study regarding systemic lidocaine administration in major head and neck cancer surgery. We hypothesized that intravenous lidocaine infused in the perioperative period would lead to opioid sparing and chronic postsurgical pain reduction.

METHODS/DESIGN

A total of 128 patients undergoing major head and neck surgery will be included in this prospective two-center, double-blind, randomized controlled trial. Patients will be randomly assigned to lidocaine or placebo treatment. After induction of general anesthesia, an intravenous lidocaine bolus will be administered (1.5 mg.kg^- 1), followed by a continuous infusion (2 mg.kg^- 1.h^- 1) which will be reduced in the postanesthesia care unit (1 mg.kg^- 1.h^- 1). The primary outcome measure is morphine consumption 48 h after surgery. The secondary outcomes include intraoperative remifentanil consumption, morphine consumption 24 h after surgery, and chronic postsurgical pain that will be assessed 3-6 months after surgery.

DISCUSSION

Recent evidence suggests that intravenous lidocaine can lead to opioid sparing and chronic postsurgical pain reduction for certain types of surgery. This is the first trial to prospectively investigate the efficacy and safety of intravenous lidocaine in major head and neck cancer surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02894710 . Registered on 11 August 2016.

Postoperative Cognitive Dysfunction after Coronary Artery Bypass Grafting

Postoperative cognitive dysfunction is a common complication following cardiac surgery. The incidence of cognitive dysfunction is more pronounced in patients receiving a cardiac operation than in those undergoing a non-cardiac operation. Clinical observations demonstrated that pulsatile flow was superior to nonpulsatile flow, and membrane oxygenator was superior to bubble oxygenator in terms of postoperative cognitive status. Nevertheless, cognitive assessments in patients receiving an on-pump and off-pump coronary artery bypass surgery have yielded inconsistent results. The exact mechanisms of postoperative cognitive dysfunction following coronary artery bypass grafting remain uncertain. The dual effects, neuroprotective and neurotoxic, of anesthetics should be thoroughly investigated. The diagnosis should be based on a comprehensive cognitive evaluation with neuropsychiatric tests, cerebral biomarker inspections, and electroencephalographic examination. The management strategies for cognitive dysfunction can be preventive or therapeutic. The preventive strategies of modifying surgical facilities and techniques can be effective for preventing the development of postoperative cognitive dysfunction. Investigational therapies may offer novel strategies of treatments. Anesthetic preconditioning might be helpful for the improvement of this dysfunction.

Neuroprotection against stroke and encephalopathy after cardiac surgery

Cerebral ischemia in the perioperative period is a major risk factor for stroke, encephalopathy, and cognitive decline after cardiothoracic surgery. After coronary artery bypass grafting, both stroke and encephalopathy can result in poor patient outcomes and increased mortality. Neuroprotection aims to lessen the severity and occurrence of further injury mediated by stroke and encephalopathy and to aid the recovery of conditions already present. Several pharmacological and non-pharmacological methods of neuroprotection have been investigated in experimental studies and in animal models, and, although some have shown effectiveness in protection of the central nervous system, for most, clinical research is lacking or did not show the expected results. This review summarizes the value and need for neuroprotection in the context of cardiothoracic surgery and examines the use and effectiveness of several agents and methods with an emphasis on clinical trials and clinically relevant neuroprotectants.

Effects of anesthesia on cerebral blood flow, metabolism, and neuroprotection

Administration of anesthetic agents fundamentally shifts the responsibility for maintenance of homeostasis from the patient and their intrinsic physiological regulatory mechanisms to the anesthesiologist. Continuous delivery of oxygen and nutrients to the brain is necessary to prevent irreversible injury and arises from a complex series of regulatory mechanisms that ensure uninterrupted cerebral blood flow. Our understanding of these regulatory mechanisms and the effects of anesthetics on them has been driven by the tireless work of pioneers in the field. It is of paramount importance that the anesthesiologist shares this understanding. Herein, we will review the physiological determinants of cerebral blood flow and how delivery of anesthesia impacts these processes.

Effects of local anesthetics on breast cancer cell viability and migration

Background

Breast cancer accounts for nearly a quarter of all cancers in women worldwide, and more than 90% of women diagnosed with breast cancer undergo mastectomy or breast-conserving surgery. Retrospective clinical studies have suggested that use of regional anesthesia leads to improved patient outcomes. Laboratory studies have reported that breast cancer cells are inhibited by some local anesthetics at millimolar concentration. Here, we present a comprehensive analysis of the effects of six common local anesthetics on two human breast cancer cell lines. We used concentrations ranging from those corresponding to plasma levels during regional block by local anesthetic (plasma concentration) to those corresponding to direct infiltration of local anesthetic.

Methods

Human breast cancer cell lines, MDA-MB-231 and MCF7, were incubated with each of six local anesthetics (lidocaine, mepivacaine, ropivacaine, bupivacaine, levobupivacaine, and chloroprocaine) (10 μM ~ 10 mM) for 6 to 72 h. Assays for cell viability, cytotoxicity, migration, and cell cycle were performed.

Results

High concentrations (> 1 mM) of local anesthetics applied to either MDA-MB-231 or MCF7 cells for 48 h significantly inhibited cell viability and induced cytotoxicity. At plasma concentrations (~ 10 μM) for 72 h, none of the local anesthetics affected cell viability or migration in either cell line. However, at 10 × plasma concentrations, 72-h exposure to bupivacaine, levobupivacaine or chloroprocaine inhibited the viability of MDA-MB-231 cells by > 40% (p < 0.001). Levobupivacaine also inhibited the viability of MCF7 cells by 50% (p < 0.001). None of the local anesthetics affected the viability of a non-cancerous breast cell line, MCF10A. MDA-MB-231 cell migration was inhibited by 10 × plasma concentrations of levobupivacaine, ropivacaine or chloroprocaine and MCF7 cell migration was inhibited by mepivacaine and levobupivacaine (p < 0.05). Cell cycle analysis showed that the local anesthetics arrest MDA-MB-231 cells in the S phase at both 1 × and 10 × plasma concentrations.

Conclusions

Local anesthetics at high concentrations significantly inhibited breast cancer cell survival. At 10 × plasma concentrations, the effect of local anesthetics on cancer cell viability and migration depended on the exposure time, specific local anesthetic, specific measurement endpoint and specific cell line.

Continuous intravenous perioperative lidocaine infusion for postoperative pain and recovery in adults

BACKGROUND

The management of postoperative pain and recovery is still unsatisfactory in a number of cases in clinical practice. Opioids used for postoperative analgesia are frequently associated with adverse effects, including nausea and constipation, preventing smooth postoperative recovery. Not all patients are suitable for, and benefit from, epidural analgesia that is used to improve postoperative recovery. The non-opioid, lidocaine, was investigated in several studies for its use in multimodal management strategies to reduce postoperative pain and enhance recovery. This review was published in 2015 and updated in January 2017.

OBJECTIVES

To assess the effects (benefits and risks) of perioperative intravenous (IV) lidocaine infusion compared to placebo/no treatment or compared to epidural analgesia on postoperative pain and recovery in adults undergoing various surgical procedures.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, and reference lists of articles in January 2017. We searched one trial registry contacted researchers in the field, and handsearched journals and congress proceedings. We updated this search in February 2018, but have not yet incorporated these results into the review.

SELECTION CRITERIA

We included randomized controlled trials comparing the effect of continuous perioperative IV lidocaine infusion either with placebo, or no treatment, or with thoracic epidural analgesia (TEA) in adults undergoing elective or urgent surgery under general anaesthesia. The IV lidocaine infusion must have been started intraoperatively, prior to incision, and continued at least until the end of surgery.

DATA COLLECTION AND ANALYSIS

We used Cochrane's standard methodological procedures. Our primary outcomes were: pain score at rest; gastrointestinal recovery and adverse events. Secondary outcomes included: postoperative nausea and postoperative opioid consumption. We used GRADE to assess the quality of evidence for each outcome.

MAIN RESULTS

We included 23 new trials in the update. In total, the review included 68 trials (4525 randomized participants). Two trials compared IV lidocaine with TEA. In all remaining trials, placebo or no treatment was used as a comparator. Trials involved participants undergoing open abdominal (22), laparoscopic abdominal (20), or various other surgical procedures (26). The application scheme of systemic lidocaine strongly varies between the studies related to both dose (1 mg/kg/h to 5 mg/kg/h) and termination of the infusion (from the end of surgery until several days after).The risk of bias was low with respect to selection bias (random sequence generation), performance bias, attrition bias, and detection bias in more than 50% of the included studies. For allocation concealment and selective reporting, the quality assessment yielded low risk of bias for only approximately 20% of the included studies.IV Lidocaine compared to placebo or no treatment We are uncertain whether IV lidocaine improves postoperative pain compared to placebo or no treatment at early time points (1 to 4 hours) (standardized mean difference (SMD) -0.50, 95% confidence interval (CI) -0.72 to -0.28; 29 studies, 1656 participants; very low-quality evidence) after surgery. Due to variation in the standard deviation (SD) in the studies, this would equate to an average pain reduction of between 0.37 cm and 2.48 cm on a 0 to 10 cm visual analogue scale . Assuming approximately 1 cm on a 0 to 10 cm pain scale is clinically meaningful, we ruled out a clinically relevant reduction in pain with lidocaine at intermediate (24 hours) (SMD -0.14, 95% CI -0.25 to -0.04; 33 studies, 1847 participants; moderate-quality evidence), and at late time points (48 hours) (SMD -0.11, 95% CI -0.25 to 0.04; 24 studies, 1404 participants; moderate-quality evidence). Due to variation in the SD in the studies, this would equate to an average pain reduction of between 0.10 cm to 0.48 cm at 24 hours and 0.08 cm to 0.42 cm at 48 hours. In contrast to the original review in 2015, we did not find any significant subgroup differences for different surgical procedures.We are uncertain whether lidocaine reduces the risk of ileus (risk ratio (RR) 0.37, 95% CI 0.15 to 0.87; 4 studies, 273 participants), time to first defaecation/bowel movement (mean difference (MD) -7.92 hours, 95% CI -12.71 to -3.13; 12 studies, 684 participants), risk of postoperative nausea (overall, i.e. 0 up to 72 hours) (RR 0.78, 95% CI 0.67 to 0.91; 35 studies, 1903 participants), and opioid consumption (overall) (MD -4.52 mg morphine equivalents , 95% CI -6.25 to -2.79; 40 studies, 2201 participants); quality of evidence was very low for all these outcomes.The effect of IV lidocaine on adverse effects compared to placebo treatment is uncertain, as only a small number of studies systematically analysed the occurrence of adverse effects (very low-quality evidence).IV Lidocaine compared to TEAThe effects of IV lidocaine compared with TEA are unclear (pain at 24 hours (MD 1.51, 95% CI -0.29 to 3.32; 2 studies, 102 participants), pain at 48 hours (MD 0.98, 95% CI -1.19 to 3.16; 2 studies, 102 participants), time to first bowel movement (MD -1.66, 95% CI -10.88 to 7.56; 2 studies, 102 participants); all very low-quality evidence). The risk for ileus and for postoperative nausea (overall) is also unclear, as only one small trial assessed these outcomes (very low-quality evidence). No trial assessed the outcomes, 'pain at early time points' and 'opioid consumption (overall)'. The effect of IV lidocaine on adverse effects compared to TEA is uncertain (very low-quality evidence).

AUTHORS' CONCLUSIONS

We are uncertain whether IV perioperative lidocaine, when compared to placebo or no treatment, has a beneficial impact on pain scores in the early postoperative phase, and on gastrointestinal recovery, postoperative nausea, and opioid consumption. The quality of evidence was limited due to inconsistency, imprecision, and study quality. Lidocaine probably has no clinically relevant effect on pain scores later than 24 hours. Few studies have systematically assessed the incidence of adverse effects. There is a lack of evidence about the effects of IV lidocaine compared with epidural anaesthesia in terms of the optimal dose and timing (including the duration) of the administration. We identified three ongoing studies, and 18 studies are awaiting classification; the results of the review may change when these studies are published and included in the review.

Neuroprotective Strategies in Repair and Replacement of the Aortic Arch

Aortic arch surgery is a technical challenge, and cerebral protection during distal anastomosis is a continued topic of controversy and discussion. The physiologic effects of hypothermic arrest and adjunctive cerebral perfusion have yet to be fully defined, and the optimal strategies are still undetermined. This review highlights the historical context, physiological rationale, and clinical efficacy of various neuroprotective strategies during arch operations.

Intravenous lidocaine infusion

Systemic lidocaine used in continuous infusion during the peri-operative period has analgesic, anti-hyperalgesic, as well as anti-inflammatory properties. This makes it capable of reducing the use of opioids and inhalational anaesthetics, and the early return of bowel function, and patient hospital stay. The aim of this narrative review was to highlight the pharmacology and indications for clinical application, along with new and interesting research areas. The clinical applications of peri-operative lidocaine infusion have been reviewed in several recent systematic reviews and meta-analyses in patients undergoing open and laparoscopic abdominal procedures, ambulatory procedures, and other types of surgery. Peri-operative lidocaine infusion may be a useful analgesic adjunct in enhanced recovery protocols. Potential benefits of intravenous lidocaine in chronic post-surgical pain, post-operative cognitive dysfunction, and cancer recurrence are under investigation. Due to its immunomodulation properties over surgical stress, current evidence suggests that intravenous lidocaine could be used in the context of multimodal analgesia.

Lidocaine dose-response effect on postoperative cognitive deficit: meta-analysis and meta-regression

INTRODUCTION

The true influence of the perioperative intravenous lidocaine on the development of postoperative cognitive deficit (POCD) in coronary artery bypass grafting (CABG) remains controversial. The principal aim is to undertake a meta-regression to determine whether moderator variables mediate the relationship between lidocaine and POCD. Areas covered: We searched the Web of Science, PubMed database, Scopus and the Cochrane Library database (up to June 2017) and systematically reviewed a list of retrieved articles. Our final review includes only randomized controlled trials (RCTs) that compared infusion of lidocaine and placebo during cardiopulmonary bypass (CPB). Mantel-Haenszel risk ratio (MH RR) and corresponding 95% confidence interval (CI) was used to report the overall effect and meta-regression analysis. A total of 688 patients in five RCTs were included. POCD occurred in 34% of all cases. Perioperative lidocaine reduces POCD (MH RR 0.702 (95% CI: 0.541-0.909). Younger age, male gender, longer CPB and higher concentration of lidocaine significantly mediate the relationship between lidocaine and POCD in favour of the neuroprotective effect of lidocaine. Expert commentary: The neuroprotective effect of lidocaine on POCD is consistent in spite of longer CPB time. A higher concentration of lidocaine strengthened the neuroprotective effect of lidocaine.

Neuroprotective Anesthesia Regimen and Intensive Management for Pediatric Cardiac Surgery with Cardiopulmonary Bypass: a Review and Initial Experience

This article describes our proposal for routine anesthesia, intraoperative medical management, cerebral and physiological monitoring during pediatric cardiac surgery with cardiopulmonary bypass that intend to provide appropriate anesthesia (analgesia, hypnosis), neuroprotection, adequate cerebral and systemic oxygen supply, and preventing against drugs neurotoxicity. A concise retrospective data is presented.

Post-Operative Cognitive Dysfunction: An exploration of the inflammatory hypothesis and novel therapies

Post-Operative Cognitive Dysfunction (POCD) is a highly prevalent condition with significant clinical, social and financial impacts for patients and their communities. The underlying pathophysiology is becoming increasingly understood, with the role of neuroinflammation and oxidative stress secondary to surgery and anaesthesia strongly implicated. This review aims to describe the putative mechanisms by which surgery-induced inflammation produces cognitive sequelae, with a focus on identifying potential novel therapies based upon their ability to modify these pathways.

Perioperative Use of Intravenous Lidocaine

Perioperative lidocaine infusion improves analgesia and recovery after some surgical procedures, possibly through systemic antiinflammatory effects. This commentary provides the clinician with evidence for rational use of perioperative lidocaine infusion in procedures where it is of demonstrated benefit.

Continuous Lidocaine Infusion as Adjunctive Analgesia in Intensive Care Unit Patients

Despite a paucity of data, the role of intravenous lidocaine (IVLI) as adjunctive analgesia in the intensive care unit (ICU) seems promising due to a low potential to contribute to respiratory depression. A retrospective chart review was conducted to evaluate the safety and effectiveness of IVLI for the treatment of pain in ICU patients with varying degrees of organ dysfunction from March 2014 to March 2016. The primary outcomes included the time to a ≥20% reduction in pain scores after the initiation of IVLI and the difference in opioid requirements as well as pain scores prior to and during IVLI therapy. Other variables included the presence of IVLI-related adverse events and the dosage and duration of IVLI. A total of 21 ICU patients were included from 2 different hospitals. The mean time to a ≥20% reduction in pain scores from the start of IVLI was 3.3 hours (SD = 2.2). The median morphine dose equivalents required during 6, 12, and 24 hours pre-IVLI were significantly higher compared to the same time periods after IVLI (18.3 vs 10 mg, P = .002; 41.8 vs 18.3 mg, P = .002; 93.5 vs 30.5 mg, P = .037). Neurological adverse effects of lidocaine were noted in 3 patients, but the effects were reversed on IVLI discontinuation. This report suggests that IVLI as an adjunctive agent in the treatment of acute pain may be a potential option in ICU patients who are refractory to opioids or those in whom opioid-induced respiratory depression is a concern.

Aortic Arch Atheroma: Stroke Reduction in Cardiac Surgical Patients

Cardiac surgery is increasingly performed on elderly patients with extensive coronary artery abnormalities who have impaired left ventricular function, decreased physiologic reserve, and multiple comorbid conditions. Considerable numbers of these patients develop perioperative neurologic complications ranging from subtle cognitive dysfunction to more evident postoperative confusion, delirium, and, less commonly, clinically apparent stroke. Magnetic resonance imaging studies have elucidated that a considerable number of patients have new ischemic brain infarcts, particularly after conventional coronary artery bypass graft surgery. Mechanisms of cerebral injury during and after cardiac surgery are discussed. Intraoperative transesophageal echocardiography and epiaortic scanning for detection of atheromatous disease of the proximal thoracic aorta is paramount in identifying patients at high risk from neurologic injury. It is important to recognize that our efforts to minimize neurologic injury should not be limited to the intraoperative period. Particular efforts should be directed to temperature management, glycemia control, and pharmacologic neuroprotection extending into the postoperative period. Preoperative magnetic resonance angiography may be of value for screening patients with significant atheroma of the proximal thoracic aorta. It is likely that for patients with no significant atheromatous disease, conventional coronary artery revascularization is the most effective long-term strategy, whereas patients with atheromatous thoracic aorta may be better managed with beating heart surgery, hybrid techniques, or medical therapy alone. Patient stratification based on the aortic atheromatic burden should be addressed in future trials designed to tailor treatment strategies to improve long-term outcomes of coronary heart disease and reduce the risks of perioperative neurologic injury.

Administration of lidocaine to prevent cognitive deficit in patients undergoing coronary artery bypass grafting and valve plasty: a systematic review and meta-analysis

INTRODUCTION

The administration of lidocaine to maintain cognitive function following coronary artery bypass grafting (CABG) and valve plasty is a controversial concept in terms of its effectiveness. We performed a systematic review to determine the effectiveness of treatment with lidocaine in preventing the occurrence of cognitive deficit after cardiac surgery. Area covered: To review the current literature on the subject, we searched the PubMed database and the Cochrane Library database (up to May 2015) and compiled a list of retrieved articles. Our final review includes only randomized controlled trials (RCTs) that compared lidocaine to a control (placebo) following CABG and valve plasty. Statistical analysis of the odds ratio (OR) and corresponding 95% confidence interval (CI) were used to determine the overall effectiveness of lidocaine for the prevention of cognitive deficit with both procedures. The Mantel-Haenszel method was used to pool data of the outcomes of cognitive deficit occurrence into fixed-effect model meta-analyses. Five RCTs were included in this study, with a total of 688 patients. Perioperative administration of lidocaine in patients undergoing cardiac surgery reduced occurrence of cognitive deficit (OR 0.583 [95% CI 0.438-0.777]; Z = -3.680; P = 0.00; I² = 52%). No significant difference in the early occurrence of cognitive deficit was revealed in patients after cardiac surgery (OR 0.909 [95% CI 0.600-1.376]; Z = -0.451; P = 0.652; I² = 11%). Expert commentary: Cognitive deficit associated with cardiac surgery is a common postoperative event. Lidocaine is contributed to a significantly reduced occurrence of cognitive deficit. Cognitive deficit management is recommended.

Lidocaine Did Not Reduce Neuropsychological-Cognitive Decline in Patients 6 Months After Supratentorial Tumor Surgery: A Randomized, Controlled Trial

: There is equivocal evidence examining cognitive improvement in response to lidocaine during cardiac surgery; however, no study has examined its effect on postoperative neuropsychological-cognitive decline after supratentorial tumor surgery.

METHODS

Ninety-four patients scheduled for supratentorial craniotomy were enrolled. Patients received either a dose of lidocaine (2%) via an intravenous bolus (1.5 mg/kg) after induction followed by an infusion at a rate of 2 mg/kg/h until the end of surgery (Lidocaine group) or the same volume of normal saline. The neuropsychological-cognitive decline was evaluated using the following tests: the Mini-Mental State Examination, the Information-Memory-Concentration test, the Hamilton Rating Scale for Depression, and the Hamilton Rating Scale for Anxiety. The cerebral oxygen extraction ratio and the difference in lactic acid levels between the bulb of the jugular vein and a peripheral artery were measured.

RESULTS

Eighty patients completed the neuropsychological tests, with 40 patients in each group. The incidence of postoperative decline at up to 6 months in the Lidocaine group was not significantly different than that in the Normal saline group. When the 2 cognitive tests were examined independent of the other tests, there was no difference between groups at 6 months. The cerebral oxygen extraction ratio was significantly lower in the Lidocaine group after surgery (P<0.05), and the arteriovenous difference of lactic acid was lower in the Lidocaine group (P<0.05).

CONCLUSIONS

Intraoperative infusion of lidocaine does not significantly decrease the incidence of postoperative neuropsychological-cognitive decline in patients 6 months after supratentorial tumor surgery.

Effect of intravenous lidocaine on the transcerebral inflammatory response during cardiac surgery: a randomized-controlled trial

PURPOSE

Postoperative cognitive dysfunction (POCD) occurs frequently after cardiac surgery. The pathophysiology of POCD remains elusive, but previous work showed that intravenous lidocaine may be protective against POCD, possibly by modulating cerebral inflammation. We hypothesized that intravenous lidocaine would attenuate the cerebral inflammatory response to cardiopulmonary bypass (CPB) by reducing the transcerebral activation gradients of platelets, leukocytes, and/or platelet-leukocyte conjugates.

METHODS

We studied 202 patients undergoing cardiac surgery with CPB in this prospective randomized double-blinded placebo-controlled trial. Subjects were randomized to receive either intravenous lidocaine (bolus + 48-hr infusion) or placebo (identical infusion volume and duration). Paired jugular venous and radial arterial blood samples were drawn at several time points and analyzed by fluorescence-activated cell sorting to identify activated platelets and platelet-leukocyte conjugates. Transcerebral activation gradients were calculated by subtracting arterial values from venous values and were compared between groups using repeated measures regression models with covariate adjustment for age, sex, surgery type, and CPB duration.

RESULTS

Beginning after aortic cross-clamp release and peaking ten minutes after the termination of CPB, the mean (SD) transcerebral activation gradient of platelet-monocyte conjugates decreased in lidocaine-treated vs placebo-treated patients [-1.84 (11.47) mean linear fluorescence intensity (MLFI) vs 1.46 (13.88) MLFI, respectively; mean difference, -4.08 MLFI; 95% confidence interval, -7.86 to -0.29; P = 0.03). No difference was seen at any time point for activated platelets or for platelet-neutrophil conjugates.

CONCLUSION

While lidocaine did not affect the systemic or transcerebral activation of platelets or leukocytes, we did observe a reduction in the transcerebral activation of platelet-monocyte conjugates after aortic cross-clamp release. This may be a manifestation of reduced cerebral inflammation during cardiopulmonary bypass in response to treatment with lidocaine. This trial was registered at ClinicalTrials.gov (NCT00938964).

Risk Factors Associated with Cognitive Decline after Cardiac Surgery: A Systematic Review

Modern day cardiac surgery evolved upon the advent of cardiopulmonary bypass machines (CPB) in the 1950s. Following this development, cardiac surgery in recent years has improved significantly. Despite such advances and the introduction of new technologies, neurological sequelae after cardiac surgery still exist. Ischaemic stroke, delirium, and cognitive impairment cause significant morbidity and mortality and unfortunately remain common complications. Postoperative cognitive decline (POCD) is believed to be associated with the presence of new ischaemic lesions originating from emboli entering the cerebral circulation during surgery. Cardiopulmonary bypass was thought to be the reason of POCD, but randomised controlled trials comparing with off-pump surgery show contradictory results. Attention has now turned to the growing evidence that perioperative risk factors, as well as patient-related risk factors, play an important role in early and late POCD. Clearly, identifying the mechanism of POCD is challenging. The purpose of this systematic review is to discuss the literature that has investigated patient and perioperative risk factors to better understand the magnitude of the risk factors associated with POCD after cardiac surgery.

Postoperative Cognitive Dysfunction: Minding the Gaps in Our Knowledge of a Common Postoperative Complication in the Elderly

Postoperative cognitive dysfunction (POCD) is a common complication associated with significant morbidity and mortality in elderly patients. There is much interest in and controversy about POCD, reflected partly in the increasing number of articles published on POCD recently. Recent work suggests surgery may also be associated with cognitive improvement in some patients, termed postoperative cognitive improvement (POCI). As the number of surgeries performed worldwide approaches 250 million per year, optimizing postoperative cognitive function and preventing/treating POCD are major public health issues. In this article, we review the literature on POCD and POCI, and discuss current research challenges in this area.

Continuous intravenous perioperative lidocaine infusion for postoperative pain and recovery

BACKGROUND

The management of postoperative pain and recovery is still unsatisfactory in clinical practice. Opioids used for postoperative analgesia are frequently associated with adverse effects including nausea and constipation. These adverse effects prevent smooth postoperative recovery. On the other hand not all patients may be suited to, and take benefit from, epidural analgesia used to enhance postoperative recovery. The non-opioid lidocaine was investigated in several studies for its use in multi-modal management strategies to reduce postoperative pain and enhance recovery.

OBJECTIVES

The aim of this review was to assess the effects (benefits and risks) of perioperative intravenous lidocaine infusion compared to placebo/no treatment or compared to epidural analgesia on postoperative pain and recovery in adults undergoing various surgical procedures.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 5 2014), MEDLINE (January 1966 to May 2014), EMBASE (1980 to May 2014), CINAHL (1982 to May 2014), and reference lists of articles. We searched the trial registry database ClinicalTrials.gov, contacted researchers in the field, and handsearched journals and congress proceedings. We did not apply any language restrictions.

SELECTION CRITERIA

We included randomized controlled trials comparing the effect of continuous perioperative intravenous lidocaine infusion either with placebo, or no treatment, or with epidural analgesia in adults undergoing elective or urgent surgery under general anaesthesia. The intravenous lidocaine infusion must have been started intraoperatively prior to incision and continued at least until the end of surgery.

DATA COLLECTION AND ANALYSIS

Trial quality was independently assessed by two authors according to the methodological procedures specified by the Cochrane Collaboration. Data were extracted by two independent authors. We collected trial data on postoperative pain, recovery of gastrointestinal function, length of hospital stay, postoperative nausea and vomiting (PONV), opioid consumption, patient satisfaction, surgical complication rates, and adverse effects of the intervention.

MAIN RESULTS

We included 45 trials involving 2802 participants. Two trials compared intravenous lidocaine versus epidural analgesia. In all the remaining trials placebo or no treatment was used as a comparator. Trials involved participants undergoing open abdominal (12), laparoscopic abdominal (13), or various other surgical procedures (20).The risk of bias was low with respect to selection bias (random sequence generation), performance bias, attrition bias, and detection bias in more than 50% of the included studies. For allocation concealment and selective reporting the quality assessment yielded low risk of bias for only approximately 20% of the included studies.We found evidence of effect for intravenous lidocaine on the reduction of postoperative pain (visual analogue scale, 0 to 10 cm) compared to placebo or no treatment at 'early time points (one to four hours)' (mean difference (MD) -0.84 cm, 95% confidence interval (CI) -1.10 to -0.59; low-quality evidence) and at 'intermediate time points (24 hours)' (MD -0.34 cm, 95% CI -0.57 to -0.11; low-quality evidence) after surgery. However, no evidence of effect was found for lidocaine to reduce pain at 'late time points (48 hours)' (MD -0.22 cm, 95% CI -0.47 to 0.03; low-quality evidence). Pain reduction was most obvious at 'early time points' in participants undergoing laparoscopic abdominal surgery (MD -1.14, 95% CI -1.51 to -0.78; low-quality evidence) and open abdominal surgery (MD -0.72, 95% CI -0.96 to -0.47; moderate-quality evidence). No evidence of effect was found for lidocaine to reduce pain in participants undergoing all other surgeries (MD -0.30, 95% CI -0.89 to 0.28; low-quality evidence). Quality of evidence is limited due to inconsistency and indirectness (small trial sizes).Evidence of effect was found for lidocaine on gastrointestinal recovery regarding the reduction of the time to first flatus (MD -5.49 hours, 95% CI -7.97 to -3.00; low-quality evidence), time to first bowel movement (MD -6.12 hours, 95% CI -7.36 to -4.89; low-quality evidence), and the risk of paralytic ileus (risk ratio (RR) 0.38, 95% CI 0.15 to 0.99; low-quality evidence). However, no evidence of effect was found for lidocaine on shortening the time to first defaecation (MD -9.52 hours, 95% CI -23.24 to 4.19; very low-quality evidence).Furthermore, we found evidence of positive effects for lidocaine administration on secondary outcomes such as reduction of length of hospital stay, postoperative nausea, intraoperative and postoperative opioid requirements. There was limited data on the effect of IV lidocaine on adverse effects (e.g. death, arrhythmias, other heart rate disorders or signs of lidocaine toxicity) compared to placebo treatment as only a limited number of studies systematically analysed the occurrence of adverse effects of the lidocaine intervention.The comparison of intravenous lidocaine versus epidural analgesia revealed no evidence of effect for lidocaine on relevant outcomes. However, the results have to be considered with caution due to imprecision of the effect estimates.

AUTHORS' CONCLUSIONS

There is low to moderate evidence that this intervention, when compared to placebo, has an impact on pain scores, especially in the early postoperative phase, and on postoperative nausea. There is limited evidence that this has further impact on other relevant clinical outcomes, such as gastrointestinal recovery, length of hospital stay, and opioid requirements. So far there is a scarcity of studies that have systematically assessed the incidence of adverse effects; the optimal dose; timing (including the duration of the administration); and the effects when compared with epidural anaesthesia.

Neuroprotective effects of intravenous lidocaine on early postoperative cognitive dysfunction in elderly patients following spine surgery

Background

This study aimed to evaluate the effects of lidocaine treatment on cognitive impairment in aged patients undergoing spine surgery and to explore the underlying mechanism.

Material/Methods

Patients were randomly divided into 2 treatment groups: (1) saline (control) and (2) lidocaine. After induction of anesthesia, the lidocaine group received lidocaine as a bolus of 1 mg/kg over 5 minutes, followed by a continuous infusion at 1.5 mg/kg/h until the end of the surgery. We examined the effects of lidocaine treatment on the improvement of cognitive function using the Mini-Mental State Examination (MMSE) at preoperation and 3 days postoperation. Serum samples were collected to assess the levels of IL-6, TNF-α, MDA, S100β, and NSE before inducing anesthesia, at the end of surgery, and 3 days after the end of surgery.

Results

We found that the MMSE scores in the lidocaine group were markedly higher than those in the control group at 3 days after surgery. Moreover, lidocaine treatment markedly suppressed the release of IL-6, S100β, and NSE into the serum at the end of surgery and 3 days after the end of surgery. In the control group, serum MDA levels increased by 3 days after the end of surgery. The lidocaine group had lower serum MDA levels than those in the control group.

Conclusions

Lidocaine may be an effective neuroprotective agent in treating early postoperative cognitive dysfunction in elderly patients undergoing spine surgery.

Pre-emptive parecoxib and post-operative cognitive function in elderly patients

ABSTRACT Background: To investigate the effect of pre-emptive parecoxib sodium, given in addition to routine analgesic treatment, on post-operative cognitive function in elderly patients. Methods: Seventy elderly patients were included, who were 65-82 years of age, 48-75 kg of weight, and ASA grade I-II. Preoperative mini mental state examination (MMSE) score was ≥21 points. Patients were randomly divided into two groups: control group (group C) and parecoxib sodium group (group P). Before induction of general anesthesia, 40 mg of parecoxib sodium was injected intravenously in group P and the same volume of saline was injected in group C. Patient-controlled intravenous analgesia (PCIA) containing fentanyl and tramadol was used for post-operative pain control. A 3 ml blood sample was obtained from the peripheral vein one day before surgery, 1, 4, 24, and 72 h after surgery, and plasma cortisol, IL-6 and S100β concentrations were measured. Cognitive function was evaluated by measuring the MMSE score and a neurological test battery within 72 h after surgery. The occurrence of post-operative cognitive dysfunction (POCD), the dosage of fentanyl and tramadol used in PCIA, and the rate of additional fentanyl administration were recorded. Results: Compared to group C, post-operative plasma cortisol concentration decreased, the amount of fentanyl and tramadol used in PCIA was reduced, the rate of additional fentanyl administration decreased, and the rate of POCD was reduced in group P (P < 0.05). Conclusion: Pre-emptive analgesia with 40 mg of parecoxib sodium can reduce the incidence of POCD in elderly patients.

Effect of piracetam on the cognitive performance of patients undergoing coronary bypass surgery: A meta-analysis

Cognitive impairments are observed in numerous patients following coronary bypass surgery, and piracetam are nootropic compounds that modulate cerebral functions by directly enhancing cognitive processes. The present meta-analysis was conducted to evaluate the protective effect of piracetam on the cognitive performance of patients undergoing coronary bypass surgery. The relevant studies were identified by searching Medline, EMBASE, PubMed and the Cochrane Library up to June 2013 and the pertinent bibliographies from the retrieved studies were reviewed. Data were selected from the studies according to predefined criteria. The meta-analysis included two randomized control trials involving 184 patients and including the Syndrom-Kurz test (SKT). Findings of the meta-analysis showed that following treatment the change from baseline observed in five SKT subtest scores, conducted with piracetam patients, indicated a significant advantage over those patients that were in the placebo group. The subtests included immediate pictured object recall, weighted mean difference (WMD)=0.91, 95% confidence interval (CI) 0.51–1.31, P<0.00001; delayed pictured object recall, WMD=0.74, 95% CI 0.19–1.28, P=0.008; delayed picture recognition, WMD=0.82, 95% CI 0.31–1.31, P=0.001; immediate word recall, WMD=0.87, 95% CI 0.47–1.28, P<0.0001; and letter interference, WMD=3.46, 95% CI −5.69 to −1.23, P=0.002. These results indicated that piracetam may have been effective in improving the short-term cognitive performance of patients undergoing coronary bypass surgery. High quality, well-controlled and longer randomized trials are required to corroborate this result.