Myocardial protection in cardiac surgery: a comprehensive review of current therapies and future cardioprotective strategies

Cardiac surgery with cardiopulmonary bypass results in global myocardial ischemia-reperfusion injury, leading to significant postoperative morbidity and mortality. Although cardioplegia is the cornerstone of intraoperative cardioprotection, a number of additional strategies have been identified. The concept of preconditioning and postconditioning, despite its limited direct clinical application, provided an essential contribution to the understanding of myocardial injury and organ protection. Therefore, physicians can use different tools to limit perioperative myocardial injury. These include the choice of anesthetic agents, remote ischemic preconditioning, tight glycemic control, optimization of respiratory parameters during the aortic unclamping phase to limit reperfusion injury, appropriate choice of monitoring to optimize hemodynamic parameters and limit perioperative use of catecholamines, and early reintroduction of cardioprotective agents in the postoperative period. Appropriate management before, during, and after cardiopulmonary bypass will help to decrease myocardial damage. This review aimed to highlight the current advancements in cardioprotection and their potential applications during cardiac surgery.

Large animal models for cardiac remuscularization studies: A methodological review

Myocardial infarction is the most common cause of heart failure, one of the most fatal non-communicable diseases worldwide. The disease could potentially be treated if the dead, ischemic heart tissues are regenerated and replaced with viable and functional cardiomyocytes. Pluripotent stem cells have proven the ability to derive specific and functional cardiomyocytes in large quantities for therapy. To test the remuscularization hypothesis, the strategy to model the disease in animals must resemble the pathophysiological conditions of myocardial infarction as in humans, to enable thorough testing of the safety and efficacy of the cardiomyocyte therapy before embarking on human trials. Rigorous experiments and in vivo findings using large mammals are increasingly important to simulate clinical reality and increase translatability into clinical practice. Hence, this review focus on large animal models which have been used in cardiac remuscularization studies using cardiomyocytes derived from human pluripotent stem cells. The commonly used methodologies in developing the myocardial infarction model, the choice of animal species, the pre-operative antiarrhythmics prophylaxis, the choice of perioperative sedative, anaesthesia and analgesia, the immunosuppressive strategies in allowing xenotransplantation, the source of cells, number and delivery method are discussed.

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).

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.

Effect of intravenous lidocaine on ischemia-reperfusion injury in DIEP microsurgical breast reconstruction. A prospective double-blind randomized controlled clinical trial

BACKGROUND

Ischemia-reperfusion injury in free flaps is associated with tissue damage and is one of the main factors causing flap failure in reconstructive microsurgery. The aim of this study is to assess whether any ischemia-reperfusion injury takes place during a microsurgical flap reconstruction as seen through the levels of malondialdehyde (MDA) and superoxide dismutase, biomarkers of oxidative stress, and to analyze the effect of lidocaine in this process.

METHODS

Twenty-four patients operated for immediate breast reconstruction using the Deep Inferior Epigastric Perforator free flap technique were divided into two groups: one group was treated with a lidocaine intravenous perfusion and the other group with a saline perfusion. MDA and superoxide dismutase (SOD) levels were measured at several points before, during, and after surgery.

RESULTS

There was an increase in MDA levels in both groups, but the lidocaine group experienced a decrease during reperfusion. On the other hand, we observed a rise in SOD levels in both groups, but a decrease during reperfusion in the placebo group. However, these differences between groups were not statistically significant.

CONCLUSIONS

The decreased SOD activity and increased MDA content in our research prove a redox imbalance and high reactive oxygen species levels in flaps, indicating that tissues experience ischemia-reperfusion injury during microsurgical reconstruction. Lidocaine may have a protective effect in free flap surgery, but our results were not statistically significant, so further studies will be required.

The use of intravenous lidocaine for postoperative pain and recovery: international consensus statement on efficacy and safety

Intravenous lidocaine is used widely for its effect on postoperative pain and recovery but it can be, and has been, fatal when used inappropriately and incorrectly. The risk-benefit ratio of i.v. lidocaine varies with type of surgery and with patient factors such as comorbidity (including pre-existing chronic pain). This consensus statement aims to address three questions. First, does i.v. lidocaine effectively reduce postoperative pain and facilitate recovery? Second, is i.v. lidocaine safe? Third, does the fact that i.v. lidocaine is not licensed for this indication affect its use? We suggest that i.v. lidocaine should be regarded as a 'high-risk' medicine. Individual anaesthetists may feel that, in selected patients, i.v. lidocaine may be beneficial as part of a multimodal peri-operative pain management strategy. This approach should be approved by hospital medication governance systems, and the individual clinical decision should be made with properly informed consent from the patient concerned. If i.v. lidocaine is used, we recommend an initial dose of no more than 1.5 mg.kg^-1 , calculated using the patient's ideal body weight and given as an infusion over 10 min. Thereafter, an infusion of no more than 1.5 mg.kg^-1 .h^-1 for no longer than 24 h is recommended, subject to review and re-assessment. Intravenous lidocaine should not be used at the same time as, or within the period of action of, other local anaesthetic interventions. This includes not starting i.v. lidocaine within 4 h after any nerve block, and not performing any nerve block until 4 h after discontinuing an i.v. lidocaine infusion.

Reducing Opioid Use in Patients Undergoing Cardiac Surgery - Preoperative, Intraoperative, and Critical Care Strategies

Patients undergoing cardiothoracic surgery are exposed to opioids in the operating room and intensive care unit and after hospital discharge. Opportunities exist to reduce perioperative opioid use at all stages of care and include alternative oral and intravenous medications, novel intraoperative regional anesthetic techniques, and postoperative opioid-sparing sedative and analgesic strategies. In this review, currently used and investigational strategies to reduce the opioid burden for cardiothoracic surgical patients are explored.

Is intravenous lidocaine protective against myocardial ischaemia and reperfusion injury after cardiac surgery?

A best evidence topic was constructed using a described protocol. The three-part question addressed was: In patients undergoing cardiac surgery, does intravenous lidocaine exert a cardioprotective effect against postoperative myocardial ischaemia and reperfusion injury? Using the reported search, 461 papers were found, of which 5 studies represented the best evidence to answer the question. In 3 studies, lidocaine was associated with a postoperative fall in biomarkers of myocardial injury. An additional study lacked power, but the difference in biomarkers was marginally non-significant with a trend in favour of lidocaine. A final study evaluating ischaemic changes on continuous and 12 lead ECG found no benefit with lidocaine. The limited evidence suggests that lidocaine may be cardioprotective, although no study has demonstrated improvement in clinical outcomes. Furthermore, all trials were small studies with a multitude of dosing regimens in heterogenous patient populations. There is insufficient data to correlate dose with effect and not all studies measured plasma lidocaine concentration. The narrow therapeutic index and our current evidence base does not support lidocaine prophylaxis.

Myocardial ischaemia reperfusion injury: the challenge of translating ischaemic and anaesthetic protection from animal models to humans

Myocardial ischaemia reperfusion injury is the leading cause of death in patients with cardiovascular disease. Interventions such as ischaemic pre and postconditioning protect against myocardial ischaemia reperfusion injury. Certain anaesthesia drugs and opioids can produce the same effects, which led to an initial flurry of excitement given the extensive use of these drugs in surgery. The underlying mechanisms have since been extensively studied in experimental animal models but attempts to translate these findings to clinical settings have resulted in contradictory results. There are a number of reasons for this such as dose response, the intensity of the ischaemic stimulus applied, the duration of ischaemia and lost or diminished cardioprotection in common co-morbidities such as diabetes and senescence. This review focuses on current knowledge regarding myocardial ischaemia reperfusion injury and cardioprotective interventions both in experimental animal studies and in clinical trials.

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.

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.

Lidocaine Enhances Contractile Function of Ischemic Myocardial Regions in Mouse Model of Sustained Myocardial Ischemia

RATIONALE

Perioperative myocardial ischemia is common in high-risk patients. The use of interventional revascularisation or even thrombolysis is limited in this patient subset due to exceedingly high bleeding risks. Blockade of voltage-gated sodium channels (VGSC) with lidocaine had been suggested to reduce infarct size and cardiomyocyte cell death in ischemia/reperfusion models. However, the impact of lidocaine on cardiac function during sustained ischemia still remains unclear.

METHODS

Sustained myocardial ischemia was induced by ligation of the left anterior descending artery in 12-16 weeks old male BALB/c mice. Subcutaneous lidocaine (30 mg/kg) was used to block VGSC. Cardiac function was quantified at baseline and at 72h by conventional and speckle-tracking based echocardiography to allow high-sensitivity in vivo phenotyping. Infarct size and cardiomyocyte cell death were assessed post mortem histologically and indirectly using troponin measurements.

RESULTS

Ischemia strongly impaired both, global systolic and diastolic function, which were partially rescued in lidocaine treated in mice. No differences regarding infarct size and cardiomyocyte cell death were observed. Mechanistically, and as shown with speckle-tracking analysis, lidocaine specifically improves residual contractility in the ischemic but not in the remote, non-ischemic myocardium.

CONCLUSION

VGSC blockade with lidocaine rescues function of ischemic myocardium as a potential bridging to revascularisation in the setting of perioperative myocardial ischemia.

Effect of Exogenous Albumin on the Incidence of Postoperative Acute Kidney Injury in Patients Undergoing Off-pump Coronary Artery Bypass Surgery with a Preoperative Albumin Level of Less Than 4.0 g/dl

Background

Hypoalbuminemia may increase the risk of acute kidney injury (AKI). The authors investigated whether the immediate preoperative administration of 20% albumin solution affects the incidence of AKI after off-pump coronary artery bypass surgery.

Methods

In this prospective, single-center, randomized, parallel-arm double-blind trial, 220 patients with preoperative serum albumin levels less than 4.0 g/dl were administered 100, 200, or 300 ml of 20% human albumin according to the preoperative serum albumin level (3.5 to 3.9, 3.0 to 3.4, or less than 3.0 g/dl, respectively) or with an equal volume of saline before surgery. The primary outcome measure was AKI incidence after surgery. Postoperative AKI was defined by maximal AKI Network criteria based on creatinine changes.

Results

Patient characteristics and perioperative data except urine output during surgery were similar between the two groups studied, the albumin group and the control group. Urine output (median [interquartile range]) during surgery was higher in the albumin group (550 ml [315 to 980]) than in the control group (370 ml [230 to 670]; P = 0.006). The incidence of postoperative AKI in the albumin group was lower than that in the control group (14 [13.7%] vs. 26 [25.7%]; P = 0.048). There were no significant between-group differences in severe AKI, including renal replacement therapy, 30-day mortality, and other clinical outcomes. There were no significant adverse events.

Conclusion

Administration of 20% exogenous albumin immediately before surgery increases urine output during surgery and reduces the risk of AKI after off-pump coronary artery bypass surgery in patients with a preoperative serum albumin level of less than 4.0 g/dl.

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.

The potential benefits of the use of regional anesthesia in cancer patients

Cancer is a leading cause of morbidity and mortality worldwide. In light of demographic changes among other factors, it is anticipated this trend will continue. Surgical resection is the primary method of treating solid tumours. Unfortunately, even with the use of adjunct therapies, metastatic disease is a leading cause of death in people with cancer. Recent evidence suggests choice of anesthetic technique may influence cancer outcome. This review considers the latest evidence regarding local and regional anesthesia in the context of cancer biology. There is a focus on the indirect and direct mechanisms involved. An integrated approach is used such that diverse areas of research are explored; ranging from epigenetics to cell death pathways. With a better understanding of how regional anesthesia and/or local anesthetics interact with cancer cells, these techniques can be trialed and evaluated to ascertain potential clinical benefits in cancer patients. Thus far, there is insufficient evidence to warrant a change in clinical practice.

The effect of intravenous anesthetics on ischemia-reperfusion injury

The effects of intravenous anesthetics on ischemia-reperfusion injury (IRI) have been investigated in both animals and clinical studies. The protective effects and the dosages of the intravenous anesthetics on IRI were discussed in this paper. The prevention of the tissue injury after the IRI was demonstrated with intravenous anesthetics in some studies. In the future, the studies should be focused on the dosage of the anesthetics related to diminishing the tissue injuries. Further studies might be required in order to investigate the effects of the anesthetics on molecular levels.