Cardioprotective Properties of Sevoflurane in Patients Undergoing Aortic Valve Replacement with Cardiopulmonary Bypass

Influence of Anesthetics on Cardiac Index and Metabolic Outcomes in Mitral and Aortic Valve Replacement in Adults: A Randomized Clinical Study

Background

Cardiac index (CI) and metabolic response to surgery are important indicators of the course of the intraoperative period.

Objectives

This study aimed to determine the effect of sevoflurane, isoflurane, and propofol on CI and metabolic outcomes during aortic and mitral valve replacement in adults.

Methods

In this single-center prospective randomized controlled clinical study, a total of 75 patients were randomly assigned into 3 groups according to the type of anesthesia: The propofol group (n = 25), the sevoflurane group (n = 25), and the isoflurane group (n = 25). Cardiac stroke volume (SV) was determined by intraesophageal echocardiography (SV = end-diastolic volume - end-systolic volume). Cardiac output (CO) and CI were calculated according to the formulas. Oxygen consumption during surgery = CI × arteriovenous difference. Indirect calorimetry was used to determine energy expenditure during anesthesia using a spirometry device.

Results

The use of anesthetics did not change CI. Cardiac index decreased from 3 to 2.9 L/min/m2 in the propofol group, increased from 3.1 to 3.2 L/min/m2 in the sevoflurane group, and decreased from 2.9 to 2.7 L/min/m2 in the isoflurane group. Compared to inhaled anesthetics, propofol significantly reduced VO2 from 179.1 to 135.7 mL/min/m2. Propofol reduced energy expenditure from 1483.7 to 1333.5 kcal.

Conclusions

Volatile anesthetics, propofol has practically no effect on CI in an uncomplicated surgery. Anesthesia with propofol is associated with lower VO2 and better oxygen delivery to tissues. Energy consumption during propofol anesthesia decreases.

Sevoflurane Preconditioning Alleviates Posttraumatic Stress Disorder-Induced Apoptosis in the Hippocampus via the EZH2-Regulated Akt/mTOR Axis and Improves Synaptic Plasticity

Posttraumatic stress disorder (PTSD) is a persistent and severe psychological and mental disorder resulting from experiences of serious trauma or stress and is suffered by many individuals. Previous studies have shown that pretreatment with sevoflurane is efficient in reducing the incidence of PTSD. However, we require a more comprehensive understanding of the specific mechanisms by which sevoflurane works. Enhancer of zeste homolog 2 (EZH2) has been reported to be regulated by sevoflurane, and to improve patient cognition. In this study, we aimed to explore the mechanisms of sevoflurane and the role of EZH2 in PTSD cases. We explored the effects of sevoflurane and EPZ-6438 (inhibitor of EZH2) on rat behavior, followed by an investigation of EZH2 mRNA and protein expression. The effects of sevoflurane and EZH2 on neuronal survival were assessed by western blotting and TUNEL staining, while western blotting was used to examine the expression of PSD95 and the AKT/mTOR proteins. Sevoflurane preconditioning restored EZH2 expression and significantly inhibited apoptosis by regulating phosphorylation of the AKT/mTOR pathway. Synaptic plasticity was also significantly improved. These results suggest that pretreatment with sevoflurane could play an important role in PTSD prevention by regulating EZH2 expression.

Guidelines for enhanced recovery after cardiac surgery. Consensus document of Spanish Societies of Anesthesia (SEDAR), Cardiovascular Surgery (SECCE) and Perfusionists (AEP)

The ERAS guidelines are intended to identify, disseminate and promote the implementation of the best, scientific evidence-based actions to decrease variability in clinical practice. The implementation of these practices in the global clinical process will promote better outcomes and the shortening of hospital and critical care unit stays, thereby resulting in a reduction in costs and in greater efficiency. After completing a systematic review at each of the points of the perioperative process in cardiac surgery, recommendations have been developed based on the best scientific evidence currently available with the consensus of the scientific societies involved.

Anaesthesia and ICU sedation with sevoflurane do not reduce myocardial injury in patients undergoing cardiac surgery: A randomized prospective study

BACKGROUND

To evaluate the effect of anaesthesia and ICU sedation with sevoflurane to protect the myocardium against ischemia-reperfusion injury associated to cardiac surgery assessed by troponin release.

METHODS

We performed a prospective, open-label, randomized study in cardiac surgery with cardiopulmonary bypass. Patients were randomized to an algorithm-based intervention group and a control group. The main outcome was the perioperative kinetic of cardiac troponin I (cTnI). The secondary outcomes included composite endpoint, GDF-15 (macrophage inhibitory cytokine-1) value, arterial lactate levels, and the length of stay (LOS) in the ICU.

RESULTS

Of 82 included patients, 81 were analyzed on an intention-to-treat basis (intervention group: n = 42; control group: n = 39). On inclusion, the intervention and control groups did not differ significantly in terms of demographic and surgical data. The postoperative kinetics of cTnI did not differ significantly between groups: the mean difference was 0.44 ± 1.09 μg/ml, P = .69. Incidence of composite endpoint and GDF-15 values were higher in the sevoflurane group than in propofol group. The intervention and control groups did not differ significantly in terms of ICU stay and hospital stay.

CONCLUSION

The use of an anaesthesia and ICU sedation with sevoflurane was not associated with a lower incidence of myocardial injury assessed by cTnI. Sevoflurane administration was associated with higher prevalence of acute renal failure and higher GDF-15 values.

A Comparison of Volatile Anesthesia and Total Intravenous Anesthesia (TIVA) Effects on Outcome From Cardiac Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

The primary objective of this study was to compare one-year mortality in patients undergoing cardiac surgery with volatile anesthesia or total intravenous anesthesia (TIVA). Secondary objectives were to compare in-hospital and 30-day mortality, postoperative levels of creatine kinase (CK-MB) and cardiac troponin, and durations of tracheal intubation, intensive care unit (ICU) and hospital stays.

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs).

SETTING

International, multi-institution centers.

PARTICIPANTS

Adults patients undergoing heart surgery.

INTERVENTIONS

Volatile anesthesia and TIVA.

MEASUREMENTS AND MAIN RESULTS

Meta-analysis found no statistically significant difference between patients receiving TIVA and volatile anesthesia in one-year mortality (n = 6440, OR = 1.22, 95% CI 0.97 to 1.54, p = 0.09, Z = 1.67, I² = 0%), troponin (n = 3127, SMD = 0.26, 95% CI -0.01 to 0.52, p = 0.05, Z = 1.92, I² = 90%) and CK-MB concentration 24h postoperatively (n = 1214, SMD = 0.10, 95% CI -0.17 to 0.36, unadjusted p = 0.48, Z = 0.71, I² = 79%), or time to tracheal extubation (n = 1059, SMD = 0.10, 95% CI -0.28 to 0.49, p = 0.60, Z = 0.53, I2 = 88%). The durations of ICU stay (n = 2003, SMD = 0.29, 95% CI 0.01 to 0.57, p = 0.04, Z = 2.05, I² = 88%) and hospital stay (n = 1214, SMD = 0.42, 95% CI 0.10 to 0.75, p = 0.01, Z = 2.53, I² = 91%) were shorter in the volatile anesthetic compared to TIVA group.

CONCLUSIONS

No significant differences in mortality (in-hospital, 30-day, 1-year), troponin and CK-MB concentrations 24 h postoperatively, or time to tracheal extubation were found between patients who had volatile anesthesia or TIVA. Compared to TIVA, volatile anesthesia was associated with shorter durations of hospital and ICU stays.

Volatile Anesthetics versus Propofol for Cardiac Surgery with Cardiopulmonary Bypass

Background

The aim of this systematic review and meta-analysis was to assess the effect of anesthesia maintenance with volatile agents compared with propofol on both short- and long-term mortality (primary outcomes) and major clinical events in adults undergoing cardiac surgery with cardiopulmonary bypass.

Methods

Randomized clinical trials on the effects of current volatile anesthetics versus propofol in adults undergoing cardiac surgery with cardiopulmonary bypass were searched (1965 to September 30, 2019) in PubMed, the Cochrane Library, and article reference lists. A random effect model on standardized mean difference for continuous outcomes and odds ratio for dichotomous outcomes were used to meta-analyze data.

Results

In total, 37 full-text articles (42 studies, 8,197 participants) were included. The class of volatile anesthetics compared with propofol was associated with lower 1-yr mortality (5.5 vs. 6.8%; odds ratio, 0.76 [95% CI, 0.60 to 0.96]; P = 0.023), myocardial infarction (odds ratio, 0.60 [95% CI, 0.39 to 0.92]; P = 0.023), cardiac troponin release (standardized mean difference, −0.39 [95% CI, −0.59 to −0.18], P = 0.0002), need for inotropic medications (odds ratio, 0.40 [95% CI, 0.24 to 0.67]; P = 0.0004), extubation time (standardized mean difference, −0.35 [95% CI, −0.68 to −0.02]; P = 0.038), and with higher cardiac index/output (standardized mean difference, 0.70 [95% CI, 0.37 to 1.04]; P < 0.0001). The class of volatile anesthetics was not associated with changes in short-term mortality (1.63 vs. 1.65%; odds ratio, 1.04 [95% CI, 0.73 to 1.49]; P = 0.820) and acute kidney injury (odds ratio, 1.25 [95% CI, 0.77 to 2.03]; P = 0.358).

Conclusions

In adults undergoing cardiac surgery with cardiopulmonary bypass, the class of volatile anesthetics was superior to propofol with regard to long-term mortality, as well as to many secondary outcomes indicating myocardial protection.

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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.

Remote ischemic preconditioning triggers changes in autonomic nervous system activity: implications for cardioprotection

Cardioprotective efficacy of remote ischemic preconditioning (RIPC) remains controversial. Experimental studies investigating RIPC have largely monitored cardiovascular changes during index ischemia and reperfusion with little work investigating changes during RIPC application. This work aims to identify cardiovascular changes associated with autonomic nervous system (ANS) activity during RIPC and prior to index ischemia. RIPC was induced in anesthetized male C57/Bl6 mice by four cycles of 5 min of hindlimb ischemia using inflated cuff (200 mmHg) followed by 5 min reperfusion. Electrocardiography (ECG) and microcirculatory blood flow in both hindlimbs were recorded throughout RIPC protocol. Heart rate variability (HRV) analysis was performed using ECG data. Hearts extracted at the end of RIPC protocol were used either for measurement of myocardial metabolites using high‐performance liquid chromatography or for Langendorff perfusion to monitor function and injury during 30 min index ischemia and 2 h reperfusion. Isolated‐perfused hearts from RIPC animals had significantly less infarct size after index ischemia and reperfusion (34 ± 5% vs. 59 ± 7%; mean ± SE P < 0.05). RIPC protocol was associated with increased heart rate measured both in ex vivo and in vivo. Frequency ratio of HRV spectra was altered in RIPC compared to control. RIPC was associated with a standard hyperemic response in the cuffed‐limb but there was a sustained reduction in blood flow in the uncuffed contralateral limb. RIPC hearts (prior to index ischemia) had significantly lower phosphorylation potential and energy charge compared to the control group. In conclusion, RIPC is associated with changes in ANS activity (heart rate, blood flow, HRV) and mild myocardial ischemic stress that would contribute to cardioprotection.

Sedation After Cardiac Surgery: Is One Drug Better Than Another?

The classic high-dose narcotic-based cardiac anesthetic has been modified to facilitate a fast-track, rapid recovery in the intensive care unit (ICU). Postoperative sedation is consequently now an essential component in recovery of the patient undergoing cardiac surgery. It must facilitate the patient's unawareness of the environment as well as reduce the discomfort and anxiety caused by surgery, intubation, mechanical ventilation, suction, and physiotherapy. Benzodiazepines seem well suited for this role, but propofol, opioids, and dexmedetomidine are among other agents commonly used for sedation in the ICU. However, what is an ideal sedative for this application? When compared with benzodiazepine-based sedation regimens, nonbenzodiazepines have been associated with shorter duration of mechanical ventilation and ICU length of stay. Current sedation guidelines recommend avoiding benzodiazepine use in the ICU. However, there are no recommendations on which alternatives should be used. In postcardiac surgery patients, inotropes and vasoactive medications are often required because of the poor cardiac function. This makes sedation after cardiac surgery unique in comparison with the requirements for most other ICU patient populations. We reviewed the current literature to try to determine if 1 sedative regimen might be better than others; in particular, we compare outcomes of propofol and dexmedetomidine in postoperative sedation in the cardiac surgical ICU.

A clinical review of inhalation anesthesia with sevoflurane: from early research to emerging topics

A large number of studies during the past two decades have demonstrated the efficacy and safety of sevoflurane across patient populations. Clinical researchers have also investigated the effects of sevoflurane, its hemodynamic characteristics, its potential protective effects on several organ systems, and the incidence of delirium and cognitive deficiency. This review examines the clinical profiles of sevoflurane and other anesthetic agents, and focuses upon emerging topics such as organ protection, postoperative cognitive deficiency and delirium, and novel ways to improve postanesthesia outcomes.

Comparison of the myocardial protective effect of sevoflurane versus propofol in patients undergoing heart valve replacement surgery with cardiopulmonary bypass

BACKGROUND

This study aimed to compare myocardial protective effects of anaesthesia with intravenous infusion of propofol versus inhalation of sevoflurane in patients undergoing heart valve replacement surgery with cardiopulmonary bypass.

METHODS

Seventy-six patients undergoing valve replacement with cardiopulmonary bypass were randomly assigned to propofol or sevoflurane anesthesia during the surgery, respectively. For assessing myocardial injury, cardiac troponin I (cTnI) and creatine kinase isozyme (CK-MB) were determined before induction (T₀), 0.5 h (T₁) and 3 h (T₂) after aortic unclamping, and 24 h (T₃) and 48 h (T₄) after surgery. The concentrations of interleukin (IL)-6 and IL-10 as the systemic inflammatory and anti-inflammatory markers were also measured at above time points.

RESULTS

In the sevoflurane group, the plasma concentrations of cTnI and CK-MB from T_l to T₄ and the levels of IL-6 and IL-10 from T₁ to T₂ were lower than those in the propofol group. Moreover, a higher ratio of automatic heart beat recovery and a shorter length of intensive care unit or hospital stay were found in the sevoflurane group comparing with the propofol group.

CONCLUSION

Sevoflurane anaesthesia produced more prominent myocardial protection and attenuated inflammatory response than propofol anaesthesia in patients with valve replacement surgery under cardiopulmonary bypass, resulting in shorter ICU and in-hospital stay.

RETROSPECTIVE CLINICAL TRIAL REGISTRATION

Identified as ChiCTR-IOR-16009979 at http://www.chictr.org.cn/ .

Comparison of the effects of inhalational anesthesia with desflurane and total intravenous anesthesia on cardiac biomarkers after aortic valve replacement

Objective (s):

The aim of this study was to compare the effects of using inhalational anesthesia with desflurane with that of a total intravenous (iv) anesthetic technique using midazolam-fentanyl-propofol on the release of cardiac biomarkers after aortic valve replacement (AVR) for aortic stenosis (AS). The specific objectives included (a) determination of the levels of ischemia-modified albumin (IMA) and cardiac troponin I (cTnI) as markers of myocardial injury, (b) effect on mortality, morbidity, duration of mechanical ventilation, length of Intensive Care Unit (ICU) and hospital stay, incidence of arrhythmias, pacing, cardioversion, urine output, and serum creatinine.

Methodology and Design:

Prospective randomized clinical study.

Setting:

Operation room of a cardiac surgery center of a tertiary teaching hospital.

Participants:

Seventy-six patients in New York Heart Association classification II to III presenting electively for AVR for severe symptomatic AS.

Interventions:

Patients included in the study were randomized into two groups and subjected to either a desflurane-fentanyl based technique or total IV anesthesia (TIVA). Blood samples were drawn at preordained intervals to determine the levels of IMA, cTnI, and serum creatinine.

Measurements and Main Results:

The IMA and cTnI levels were not found to be significantly different between both the study groups. Patients in the desflurane group were found to had significantly lower ICU and hospital stays and duration of postoperative mechanical ventilation as compared to those in the TIVA group. There was no difference found in mean heart rate, urine output, serum creatinine, incidence of arrhythmias, need for cardioversion, and 30-day mortality between both groups. The patients in the TIVA group had higher mean arterial pressures on weaning off cardiopulmonary bypass as well as postoperatively in the ICU and recorded lower inotrope usage.

Conclusion:

The result of our study remains ambiguous regarding the overall protective effect of desflurane in patients undergoing AVR although some benefit in terms of shorter duration of postoperative mechanical ventilation, ICU and hospital stays, as well as cTnI, were seen. However, no difference in overall outcome could be clearly established between patients who received desflurane and those that were managed solely with IV anesthetic technique using propofol.

The mechanisms of cardio-protective effects of desflurane and sevoflurane at the time of reperfusion: anaesthetic post-conditioning potentially translatable to humans?

Myocardial conditioning is actually an essential strategy in the management of ischaemia-reperfusion injury. The concept of anaesthetic post-conditioning is intriguing, its action occurring at a pivotal moment (that of reperfusion when ischaemia reperfusion lesions are initiated) where the activation of these cardio-protective mechanisms could overpower the mechanisms leading to ischaemia reperfusion injuries. Desflurane and sevoflurane are volatile anaesthetics frequently used during cardiac surgery. This review focuses on the efficacy of desflurane and sevoflurane administered during early reperfusion as a potential cardio-protective strategy. In the context of experimental studies in animal models and in human atrial tissues in vitro, the mechanisms underlying the cardio-protective effect of these agents and their capacity to induce post-conditioning have been reviewed in detail, underlining the role of reactive oxygen species generation, the activation of the cellular signalling pathways, and the actions on mitochondria along with the translatable actions in humans; this might well be sufficient to set the basis for launching randomized clinical studies, actually needed to confirm this strategy as one of real impact.

Effects of Sevoflurane Inhalation During Cardiopulmonary Bypass on Pediatric Patients: A Randomized Controlled Clinical Trial

The effects of sevoflurane inhalation during cardiopulmonary bypass (CPB) on postoperative courses and serum cardiac troponin I (cTnI) concentrations in pediatric patients undergoing cardiac surgery have not been extensively investigated. In this single-center, prospective, randomized trial, an anesthetic regimen containing 2% sevoflurane used throughout the CPB process was compared with a total intravenous anesthesia (TIVA) regimen. One hundred and three patients undergoing congenital heart defect repair with CPB were included in this prospective randomized controlled study. They were randomized into two groups: the sevoflurane group, who received 2% sevoflurane during CPB via an oxygenator, and the control group, who received only an oxygen-air mixture. The pre- and intra-operative parameters were comparable between the two groups. There was a slight but significant increase of arterial diastolic pressure in the sevoflurane group immediately after CPB compared with control patients (46.9 ± 9.3 mm Hg vs. 43.6 ± 8.9 mm Hg; p = 0.033). There was no death in either group. The postoperative ventilation time (in mean [95% confidence interval]) was shorter in the sevoflurane group than that in the control group (26.1 [19.2, 33.0] h vs. 37.7 [24.4, 50.9] h; p = 0.014). The postoperative ICU time, hospital days, and serial serum cTnI concentrations were not significantly different between the two groups. Inhalation of 2% sevoflurane during CPB is beneficial to the recovery of pediatric patients undergoing cardiac surgery but has no significant effect on postoperative cTnI release.

Meta-analysis of the cardioprotective effect of sevoflurane versus propofol during cardiac surgery

BACKGROUND

To evaluate the cardioprotective effects of sevoflurane versus propofol anesthesia in patients undergoing cardiac surgery.

METHODS

Studies were retrieved through searching several databases. Study quality was evaluated by Jadad scale. Meta-analysis was performed with RevMan5.0 software. Publication bias was tested by funnel plot.

RESULTS

As a result, 15 studies were included. Compared with propofol, sevoflurane anesthesia significantly improved postoperative (WMD (weighted mean difference) = 0.62, 95% CI: 0.33 to 0.92; P < 0.0001) and postoperative 12 hour cardiac index (WMD = 0.18, 95% CI: 0.03 to 0.33; P = 0.02), postoperative cardiac output (WMD = 1.14, 95% CI: 0.74 to 1.54; P < 0.00001), and reduced postoperative 24 hour cardiac troponin I concentration (WMD = -0.86, 95% CI:-1.49 to -0.22; P = 0.008), postoperative inotropic drug usage (OR (odds ratio) = 0.31, 95% CI: 0.22 to 0.44; P < 0.00001), vasoconstrictor drug usage (OR = 0.30, 95% CI:0.21 to 0.43; P < 0.00001), ICU stay (WMD = -15.53, 95% CI: -24.29 to -6.58; P = 0.0007) and a trial fibrillation incidence (OR = 0.25, 95% CI: 0.07 to 0.85; P = 0.03). However, no significant differences were found in other indexes. Subgroup analysis indicated the similar results.

DISCUSSION

The sevoflurane-induced cTnI reduction is associated with lower incidence of late adverse cardiac events, accounting for its roles in cardiac protection. Several limitations existed such as the small sample size and the lack use of blind design.

CONCLUSIONS

Sevoflurane may exhibit a more favorable cardioprotective effect during cardiac surgery than propofol.

Additive Effect on Survival of Anaesthetic Cardiac Protection and Remote Ischemic Preconditioning in Cardiac Surgery: A Bayesian Network Meta-Analysis of Randomized Trials

INTRODUCTION

Cardioprotective properties of volatile agents and of remote ischemic preconditioning have survival effects in patients undergoing cardiac surgery. We performed a Bayesian network meta-analysis to confirm the beneficial effects of these strategies on survival in cardiac surgery, to evaluate which is the best strategy and if these strategies have additive or competitive effects.

METHODS

Pertinent studies were independently searched in BioMedCentral, MEDLINE/PubMed, Embase, and the Cochrane Central Register (updated November 2013). A Bayesian network meta-analysis was performed. Four groups of patients were compared: total intravenous anesthesia (with or without remote ischemic preconditioning) and an anesthesia plan including volatile agents (with or without remote ischemic preconditioning). Mortality was the main investigated outcome.

RESULTS

We identified 55 randomized trials published between 1991 and 2013 and including 6,921 patients undergoing cardiac surgery. The use of volatile agents (posterior mean of odds ratio = 0.50, 95% CrI 0.28-0.91) and the combination of volatile agents with remote preconditioning (posterior mean of odds ratio = 0.15, 95% CrI 0.04-0.55) were associated with a reduction in mortality when compared to total intravenous anesthesia. Posterior distribution of the probability of each treatment to be the best one, showed that the association of volatile anesthetic and remote ischemic preconditioning is the best treatment to improve short- and long-term survival after cardiac surgery, suggesting an additive effect of these two strategies.

CONCLUSIONS

In patients undergoing cardiac surgery, the use of volatile anesthetics and the combination of volatile agents with remote preconditioning reduce mortality when compared to TIVA and have additive effects. It is necessary to confirm these results with large, multicenter, randomized, double-blinded trials comparing these different strategies in cardiac and non-cardiac surgery, to establish which volatile agent is more protective than the others and how to best apply remote ischemic preconditioning.

Late Post-Conditioning with Sevoflurane after Cardiac Surgery--Are Surrogate Markers Associated with Clinical Outcome?

Introduction

In a recent randomized controlled trial our group has demonstrated in 102 patients that late post-conditioning with sevoflurane performed in the intensive care unit after surgery involving extracorporeal circulation reduced damage to cardiomyocytes exposed to ischemia reperfusion injury. On the first post-operative day the sevoflurane patients presented with lower troponin T values when compared with those undergoing propofol sedation. In order to assess possible clinical relevant long-term implications in patients enrolled in this study, we performed the current retrospective analysis focusing on cardiac and non-cardiac events during the first 6 months after surgery.

Methods

All patients who had successfully completed the late post-conditioning trial were included into this follow-up. Our primary and secondary endpoints were the proportion of patients experiencing cardiac and non-cardiac events, respectively. Additionally, we were interested in assessing therapeutic interventions such as initiation or change of drug therapy, interventional treatment or surgery.

Results

Of 102 patients analyzed in the primary study 94 could be included in this follow-up. In the sevoflurane group (with 41 patients) 16 (39%) experienced one or several cardiac events within 6 months after cardiac surgery, in the propofol group (with 53 patients) 19 (36%, p=0.75). Four patients (9%) with sevoflurane vs. 7 (13%) with propofol sedation had non-cardiac events (p=0.61). While a similar percentage of patients suffered from cardiac and/or non-cardiac events, only 12 patients in the sevoflurane group compared to 20 propofol patients needed a therapeutic intervention (OR: 0.24, 95% CI: 0.04-1.43, p=0.12). A similar result was found for hospital admissions: 2 patients in the sevoflurane group had to be re-admitted to the hospital compared to 8 in the propofol group (OR 0.23, 95% CI: 0.04-1.29, p=0.10).

Conclusions

Sevoflurane does not seem to provide protection with regard to the occurrence of cardiac and non-cardiac events in the 6-month period following cardiac surgery with the use of extracorporeal circulation. However, there was a clear trend towards fewer interventions (less need for treatment, fewer hospital admissions) associated with sevoflurane post-conditioning in patients experiencing any event. Such results might encourage launching large multicenter post-conditioning trials with clinical outcome defined as primary endpoint.

Peri-operative anaesthetic myocardial preconditioning and protection - cellular mechanisms and clinical relevance in cardiac anaesthesia

Preconditioning has been shown to reduce myocardial damage caused by ischaemia–reperfusion injury peri-operatively. Volatile anaesthetic agents have the potential to provide myocardial protection by anaesthetic preconditioning and, in addition, they also mediate renal and cerebral protection. A number of proof-of-concept trials have confirmed that the experimental evidence can be translated into clinical practice with regard to postoperative markers of myocardial injury; however, this effect has not been ubiquitous. The clinical trials published to date have also been too small to investigate clinical outcome and mortality. Data from recent meta-analyses in cardiac anaesthesia are also not conclusive regarding intra-operative volatile anaesthesia. These inconclusive clinical results have led to great variability currently in the type of anaesthetic agent used during cardiac surgery. This review summarises experimentally proposed mechanisms of anaesthetic preconditioning, and assesses randomised controlled clinical trials in cardiac anaesthesia that have been aimed at translating experimental results into the clinical setting.

Pregnancy outcome and follow-up cardiac outcome in women with aortic valve replacement

OBJECTIVES

To compare the maternal, fetal and cardiac outcomes in women who have undergone aortic valve replacement.

METHOD

Retrospective observational study of all women with aortic valve replacement, who underwent a pregnancy (1998-2012). Maternal-, fetal- and valve-related cardiac outcomes were assessed.

RESULTS

Thirty-two pregnancies in 16 women with aortic valve replacement (nine bioprosthetic, six Ross and 17 mechanical) were evaluated. There were no adverse maternal events in the bioprosthetic and Ross groups but three in the mechanical group. Fetal loss rate was highest in the mechanical valve pregnancies (53%). One woman in the bioprosthetic group needed valve re-operation, and one woman in the mechanical valve group died. There was no difference in the change of Vmax over the follow-up between the valves (p = 0.25).

CONCLUSIONS

There was no difference in deterioration between aortic valve replacements during and after pregnancy. The highest risk of maternal and fetal complications occurred in the mechanical valve group.

Myocardial ischemic conditioning: Physiological aspects and clinical applications in cardiac surgery

Ischemia-reperfusion is a major determinant of myocardial impairment in patients undergoing cardiac surgery. The main goal of research in cardioprotection is to develop effective techniques to avoid ischemia-reperfusion lesions. Myocardial ischemic conditioning is a powerful endogenous cardioprotective phenomenon. First described in animals in 1986, myocardial ischemic conditioning consists of applying increased tolerance of the myocardium to sustained ischemia by exposing it to brief episodes of ischemia-reperfusion. Several studies have sought to demonstrate its effective cardioprotective action in humans and to understand its underlying mechanisms. Myocardial ischemic conditioning has two forms: ischemic preconditioning (IPC) when the conditioning stimulus is applied before the index ischemia and ischemic postconditioning when the conditioning stimulus is applied after it. The cardioprotective action of ischemic conditioning was reproduced by applying the ischemia-reperfusion stimulus to organs remote from the heart. This non-invasive manner of applying ischemic conditioning has led to its application in clinical settings. Clinical trials for the different forms of ischemic conditioning were mainly developed in cardiac surgery. Many studies suggest that this phenomenon can represent an interesting adjuvant to classical cardioprotection during on-pump cardiac surgery. Ischemic conditioning was also tested in interventional cardiology with interesting results. Finally, advances made in the understanding of mechanisms that underlie the cardioprotective action of ischemic conditioning have paved the way to a new form of myocardial conditioning which is pharmacological conditioning.

Late pharmacologic conditioning with volatile anesthetics after cardiac surgery

INTRODUCTION

The aim of this randomized controlled trial was to investigate whether volatile anesthetics used for postoperative sedation have any beneficial effects on myocardial injury in cardiac surgery patients after on-pump valve replacement.

METHODS

Anesthesia was performed with propofol. After arrival in the intensive care unit (ICU), 117 patients were randomized to be sedated for at least 4 hours with either propofol or sevoflurane. Sevoflurane was administered by using the anesthetic-conserving device. Troponin T, creatine kinase, creatine kinase from heart muscle tissue, myoglobin, and oxygenation index were determined on arrival at the ICU, 4 hours after sedation, and in the morning of the first postoperative day (POD1). Primary end points were cardiac injury markers on POD1. As secondary end points oxygenation, postoperative pulmonary complications, and ICU and hospital stay were documented.

RESULTS

Fifty-six patients were analyzed in the propofol arm, and 46 patients in the sevoflurane arm. Treatment groups were comparable with regard to patient demographics and intraoperative characteristics. Concentration of troponin T as the most sensitive marker for myocardial injury at POD1 was significantly lower in the sevoflurane group compared with the propofol group (unadjusted difference, -0.4; 95% CI, -0.7 to -0.1; P < 0.01; adjusted difference, -0.2; 95% CI, -0.4 to -0.02; P = 0.03, respectively).

CONCLUSIONS

The data presented in this investigation indicate that late postconditioning with the volatile anesthetic sevoflurane might mediate cardiac protection, even with a late, brief, and low-dose application.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00924222.

A comparative study of cardioprotective effect of three anesthetic agents by measuring serum level of troponin-T after coronary artery bypass grafting

BACKGROUND

Cardiac surgery is associated with some degree of myocardial injury. Preconditioning first described in 1986 was pharmacologic and non- pharmacologic. Among the long list of anesthetic drugs, isoflurane as an inhaling agent along with midazolam and propofol as injectable substances have been documented to confer some preconditioning effects on myocardium.

OBJECTIVES

In this study cardiac Troponin T (cTnT) ,as a reliable marker, was used for evaluating myocardial injury.

METHODS

This prospective double blind study was comprised of 60 patients scheduled for CABG and were randomly assigned into three groups who received infusion of propofol or midazolam or isoflorane. Surgical procedures and anesthetics were similar for 3 groups. cTnT measured preoperatively and at 12, 24 and 36hr after arrival in ICU.

RESULTS

There were no statistically significant differences in mean cTnT levels between three groups in the preoperative period and 12-24 hours after arrival in ICU. However, mean cTnT in 3 groups at 36 hours after arrival in ICU were different (P< 0.013) and cTnT level was significantly higher in midazolam group (P<0.001) and lowest in isoflurane group (P=0.002).

CONCLUSION

There were significant differences on cTnT levels between anesthetic groups of isofluran, midazolam and propofol at 36 hr after surgery. Preconditioning effect of isoflurane was higher than the other two groups.

The effect of isoflurane on survival and myocardial infarction: a meta-analysis of randomized controlled studies

OBJECTIVE

The aim of this meta-analysis was to investigate the cardioprotective properties of isoflurane versus any comparator in terms of the rate of myocardial infarction and all-cause mortality.

DESIGN

Pertinent studies were searched independently in Biomed, Central, PubMed, Embase, and the Cochrane Central Register of clinical trials. The primary endpoint was mortality at the longest follow-up available.

SETTING

A hospital.

PARTICIPANTS

Randomized controlled trials.

INTERVENTION

A meta-analysis of 37 trials.

MEASUREMENTS AND MAIN RESULTS

The 37 included trials randomized 3,539 patients in cardiac (16 studies) and in noncardiac surgery (21 studies) with noninhalation comparators in 55% of trials. The overall analysis showed no difference in mortality between the isoflurane and control groups (16/1,602 [1.0%] v 23/1,937 [1.2%], odds ratios (OR) = 0.76 [0.39-1.47], p = 0.4 with 37 studies included) and no difference in the rate of myocardial infarction (3/1,312 [0.2%] v 1/1,532 [0.07%], OR = 2.03 [0.27-15.49], p = 0.5 with 30 studies included). Mortality was reduced in the isoflurane group when only studies with a low risk of bias were included in the analyses (0/540 [0%] v 5/703 [0.7%] in the control arm, OR = 0.13 [0.02-0.76], p = 0.02) with 4 cardiac and 6 noncardiac trials included and 5 noninhalation and 5 inhalation agents as the comparator. A trend was noted when a subanalysis was performed with propofol as a comparator (1/544 [0.2%] v 6/546 [1.1%], p = 0.05, with 16 studies included).

CONCLUSIONS

Isoflurane reduced mortality in high-quality studies and showed a trend toward a reduction in mortality when it was compared with propofol. No differences in the rates of overall mortality and myocardial infarction were noted.

Sevoflurane vs. propofol in patients with coronary disease undergoing mitral surgery: a randomised study

BACKGROUND

Myocardial ischemic damage is reduced by volatile anaesthetics in patients undergoing low-risk coronary artery bypass graft surgery; few and discordant results exist in other settings. We therefore performed a randomised controlled trial (sevoflurane vs. propofol) to compare cardiac troponin release in patients with coronary disease undergoing mitral surgery.

METHODS

Patients with coronary artery disease undergoing mitral surgery were randomly allocated to receive either sevoflurane (50 patients) or propofol (50 patients) as main hypnotic. The primary endpoint of the study was peak post-operative cardiac troponin release defined as the maximum value among the post-operative values measured at intensive care unit arrival, 4 h later, on the first and second post-operative day.

RESULTS

There was no significant difference in post-operative peak troponin release, the median (25th-75th percentiles) values being 14.9 (10.1-22.1) ng/ml and 14.5 (8.8-17.6) ng/ml in the sevoflurane and propofol groups, respectively (P = 0.4). Fentanyl administration was different between the two groups: 1347 ± 447 μg in patients receiving sevoflurane and 1670 ± 469 μg in those receiving propofol, P = 0.002. The 1-year follow-up identified two patients who died in the propofol group (one myocardial infarction and one low cardiac output syndrome) and one in the sevoflurane group (myocardial infarction).

CONCLUSION

In this study, patients with coronary artery disease undergoing mitral surgery did not benefit from the cardioprotective properties of halogenated anaesthetics. Sevoflurane anaesthesia was not associated to lower cardiac troponin release when compared with propofol anaesthesia.

The mitochondrial permeability transition pore and its role in anaesthesia-triggered cellular protection during ischaemia-reperfusion injury

This review summarises the most recent data in support of the role of the mitochondrial permeability transition pore (mPTP) in ischaemia-reperfusion injury, how anaesthetic agents interact with this molecular channel, and the relevance this holds for current anaesthetic practice. Ischaemia results in damage to the electron transport chain of enzymes and sets into play the assembly of a non-specific mega-channel (the mPTP) that transgresses the inner mitochondrial membrane. During reperfusion, uncontrolled opening of the mPTP causes widespread depolarisation of the inner mitochondrial membrane, hydrolysis of ATP, mitochondrial rupture and eventual necrotic cell death. Similarly, transient opening of the mPTP during less substantial ischaemia leads to differential swelling of the intermembrane space compared to the mitochondrial matrix, rupture of the outer mitochondrial membrane and release of pro-apoptotic factors into the cytosol. Recent data suggests that cellular protection from volatile anaesthetic agents follows specific downstream interactions with this molecular channel that are initiated early during anaesthesia. Intravenous anaesthetic agents also prevent the opening of the mPTP during reperfusion. Although by dissimilar mechanisms, both volatiles and propofol promote cell survival by preventing uncontrolled opening of the mPTP after ischaemia. It is now considered that anaesthetic-induced closure of the mPTP is the underlying effector mechanism that is responsible for the cytoprotection previously demonstrated in clinical studies investigating anaesthetic-mediated cardiac and neuroprotection. Manipulation of mPTP function offers a novel means of preventing ischaemic cell injury. Anaesthetic agents occupy a unique niche in the pharmacological armamentarium available for use in preventing cell death following ischaemia-reperfusion injury.

Clinical application of the cardioprotective effects of volatile anaesthetics: CON--total intravenous anaesthesia or not total intravenous anaesthesia to anaesthetise a cardiac patient?

Although volatile anaesthetics show strong and easily reproducible cardioprotective effects in animal experiments, these effects are less obvious in clinical settings. Indeed, more than a decade after the first human clinical study, the number of publications has increased extensively, but the encouraging results from previous studies in terms of myocardial protection have failed to translate into an improvement in survival or a decrease the incidence of myocardial infarction. No consensus on the modalities of administration of volatile anaesthetics has been agreed and when the experimental protocols are transposed into daily clinical practice, their cardioprotective effects are still weak. The reasons for the disparities between experimental and clinical studies will be reviewed here, especially the role of patients' co-morbidities and medications as well as the limitations of the main positive clinical trials. Recent data showing anti-inflammatory properties of propofol will also be explained. One of the most important clinical benefits of propofol is that it can be used by target-controlled or continuous infusion for anaesthesia and sedation throughout the surgical and critical care periods without the risk of a transition failure. Further large multi-centre clinical investigations are still required.

The cellular and molecular origin of reactive oxygen species generation during myocardial ischemia and reperfusion

Myocardial ischemia-reperfusion injury is an important cause of impaired heart function in the early postoperative period subsequent to cardiac surgery. Reactive oxygen species (ROS) generation increases during both ischemia and reperfusion and it plays a central role in the pathophysiology of intraoperative myocardial injury. Unfortunately, the cellular source of these ROS during ischemia and reperfusion is often poorly defined. Similarly, individual ROS members tend to be grouped together as free radicals with a uniform reactivity towards biomolecules and with deleterious effects collectively ascribed under the vague umbrella of oxidative stress. This review aims to clarify the identity, origin, and progression of ROS during myocardial ischemia and reperfusion. Additionally, this review aims to describe the biochemical reactions and cellular processes that are initiated by specific ROS that work in concert to ultimately yield the clinical manifestations of myocardial ischemia-reperfusion. Lastly, this review provides an overview of several key cardioprotective strategies that target myocardial ischemia-reperfusion injury from the perspective of ROS generation. This overview is illustrated with example clinical studies that have attempted to translate these strategies to reduce the severity of ischemia-reperfusion injury during coronary artery bypass grafting surgery.

Volatile agents for cardiac protection in noncardiac surgery: a randomized controlled study

OBJECTIVE

Volatile anesthetics reduce the risk of myocardial infarction and mortality in coronary artery surgery. Recently, the American College of Cardiology/American Heart Association Guidelines suggested the use of volatile anesthetic agents for the maintenance of general anesthesia during noncardiac surgery in patients at risk for perioperative myocardial ischemia, but no randomized experience to document the cardioprotective effects of these agents exists in this setting. Therefore, the authors performed a prospective, randomized, controlled trial to compare the effects of sevoflurane versus total intravenous anesthesia, in terms of postoperative cardiac troponin I release in patients undergoing noncardiac surgery.

DESIGN

A randomized, controlled trial.

SETTING

A teaching hospital.

PARTICIPANTS

Eighty-eight consecutive patients undergoing noncardiac surgery.

INTERVENTIONS

Patients were allocated randomly to receive either volatile anesthetic (44 patients) as the main anesthetic agent or total intravenous anesthesia (TIVA) (44 patients).

MEASUREMENTS

Postoperative cardiac troponin I release was measured as a marker of myocardial necrosis. Patients with detectable postoperative troponin I in the sevoflurane group (12/44, 27.3%) were similar to those in the propofol group (9/44, 20.5%; p = 0.6). There was no significant reduction of postoperative median peak cTnI release (0.16 ± 0.71 ng/mL in the sevoflurane group compared with the TIVA group, 0.03 ± 0.08 ng/mL; p = 0.4). Three patients died at the 1-year follow-up for noncardiac causes (2 in the TIVA group).

CONCLUSIONS

In the authors' experience, patients undergoing noncardiac surgery did not benefit from anesthesia based on halogenated anesthetics. Further studies are necessary to evaluate the cardioprotective effects of volatile agents in noncardiac surgery.

Occupational exposure to sevoflurane during cardiopulmonary bypass

Volatile anaesthetic agents are widely used for maintenance of anaesthesia in all kinds of surgical procedures. Despite the implementation of measures such as adequate ventilation of the operating room and the use of efficient scavenging systems, concern remains about the risks for occupational exposure, especially in situations associated with an increased risk of anaesthetic gas waste, such as with the use of volatile anaesthetic agents on cardiopulmonary bypass. The present contribution reports the results of a preliminary safety assessment involving measurements of sevoflurane concentrations in the ambient air of a cardiac surgery operating room.

In 22 cardiac surgical procedures with cardiopulmonary bypass (11 with open and 11 with closed venous reservoir), measurements of trace concentrations were obtained every 10 min at the following sites: at the outlet of the oxygenator, at the outlet of the cardiotomy reservoir, in the breathing zone of the perfusionist and above the surgical field. The concentrations were measured on-line using a photoacoustic infrared spectrometer.

Mean sevoflurane waste concentrations remained consistently below the recommended target value of 4.68 ppm throughout the observation period at the different measurement sites.

These results indicate that, with the use of sevoflurane on cardiopulmonary bypass, the recommended levels for occupational exposure are not exceeded, provided adequate operation room ventilation and waste gas scavenging is performed.

[Prospects of cardioprotection by volatile anesthetics]

Myocardial ischaemia is followed by some reversibile or ireversibile changes. The aim of cardioplegia is to protect numerous intracellular processes: to spare the intracellular energy stores, to reduce the free oxygen radicals synthesis, to protect the function of the endothelium and myocardial oxygen balance as well as ionic balance. The crystalloid or blood cardioplegia, with anterograde or retrograde infusion, is a basic procedure of the intraoperative cardiac protection. Glucose-insulin-potassium solution was primarily used in a myocardial infarction. After the first promising results, some surgical teams started to use the high glucose-insulin-potassium solution, as a metabolic modulation approach, during a coronary surgery as addition to cardioplegia. During ischaemia, a number of intracellular mechanisms deteriorate with bioenergy misbalance and decrease of cellular functional reserve. In particular, the regulation of contractility in response to loading, alteration in autocrine or paracrine regulation in metabolically stressed hearts and acquired, "learned" tolerance of muscle to deteriorate perfusion (preconditioning) are examples of a variety of the cardiac adaptation. The further improvement in the metabolic modulation during a coronary surgery was made with fluorine ion halogenated volatile aneasthetics used for anaesthesia. The results of some experimental and first clinical studies induced a new approach to the modulation of the intracellular metabolic mechanisms and announced a new concept of anaesthetic preconditioning in coronary surgery. Large, randomized studies are needed to evaluate anaesthetic preconditioning and dependence of its efficiency on type and dose of volatile anaesthetics as well as the role of gene regulation in cardioprotection.

A randomized controlled trial comparing an intraoperative goal-directed strategy with routine clinical practice in patients undergoing peripheral arterial surgery

BACKGROUND AND OBJECTIVE

We hypothesized that, in vascular surgery patients, the application of a goal-directed strategy based on a pulse contour-derived cardiac index would be associated with a better haemodynamic status than the application of routine perioperative care and that the amount of fluid and/or inotropes required in such a goal-directed therapy depended on the general anaesthetic technique used.

METHODS

Patients undergoing peripheral arterial bypass grafting were randomly assigned to three groups. In group 1, haemodynamic management was performed according to routine clinical practice. In the two other groups (groups 2 and 3) a goal-directed therapy was applied aiming to maintain the pulse contour-derived cardiac index above 2.5 l m min. Patients in groups 1 and 2 received sevoflurane-based anaesthesia and patients in group 3 propofol-based anaesthesia. Haemodynamic variables, amount of fluid and administration of inotropes were assessed at different time intervals.

RESULTS

The amount of fluid administered was not significantly different between the groups. Two patients in group 1, 13 patients in group 2 and 12 patients in group 3 were treated with dobutamine (P < 0.001). None of the patients anaesthetized with sevoflurane (groups 1 and 2) experienced postoperative cardiovascular complications, whereas four patients in the total intravenous group (group 3) experienced major postoperative cardiovascular complications (P = 0.005).

CONCLUSION

In the conditions of the present study, the application of a goal-directed therapy aiming to maintain the cardiac index above 2.5 l min m did not result in a higher tissue oxygen delivery than when applying the standard haemodynamic strategy nor did it depend on the anaesthetic technique used.

The anesthesia patient with acute coronary syndrome

This article reviews the current state of knowledge of the pathophysiology, diagnosis, and treatment of acute coronary syndrome outside and during the perioperative period. It highlights some aspects of relevance for the anesthesiologist caring for these patients. Perioperative modalities for the management of patients suffering from this syndrome, the major guidelines and the evidence behind them, and possible avenues for future research is explored.

Drugs mediating myocardial protection

The occurrence of myocardial ischaemia will result in either reversible or irreversible myocardial dysfunction. Even when revascularization is successful, some reperfusion injury may occur that transiently impairs myocardial function. Therefore, treatment should not only be directed towards prompt restoration of myocardial blood flow but measures should also be taken to prevent or alleviate the consequences of myocardial reperfusion injury. Over the years, various strategies have been developed. The present contribution reviews a number of these strategies focusing on pharmacological treatments that have been developed to address myocardial reperfusion injury.

The use of a volatile anesthetic regimen protects against acute normovolemic hemodilution induced myocardial depression in patients with coronary artery disease

BACKGROUND

Previous studies indicated that acute normovolemic hemodilution (ANH) was associated with a depression of myocardial function in coronary surgery patients with baseline heart rate faster than 90 bpm. It was suggested that this phenomenon could be explained by the occurrence of myocardial ischemia. In the present study, we hypothesized that the cardioprotective properties of a volatile anesthetic regimen might protect against the ANH related myocardial functional impairment.

MATERIALS AND METHODS

Forty elective coronary surgery patients with baseline heart rate faster than 90 bpm were randomly allocated to receive different anesthetic regimens. Group A (n = 20) received midazolam-based anesthesia. Group B (n = 20) received a sevoflurane-based anesthesia. Five-lead electrocardiogram, pulse oximetry, capnography, radial arterial pressure, and Swan Ganz continuous thermodilution cardiac output via right internal jugular vein were monitored. Measurements were obtained before and after ANH. Data were compared using paired t test. All data were expressed as mean +/- SD. Data were considered significant if P < 0.05.

RESULTS

After ANH, systemic vascular resistance was slightly decreased in group A while there was a significant decrease in group B. In group A, cardiac output was slightly decreased from 5.07+/-1.17 l/min to 5.02+/-1.28 l/min after ANH, whereas in group B, cardiac output was significantly increased from 4.84+/-1.21 l/min to 6.02+/-1.28 l/min after ANH.

CONCLUSION

In coronary surgery patients, with baseline heart rate faster than 90 bpm, anesthesia with sevoflurane during ANH was associated with an improvement in myocardial function after ANH, which was not present in patients anesthetized with midazolam.

Assessment of cardiac troponin I and C-reactive protein concentrations associated with anesthetic protocols using sevoflurane or a combination of fentanyl, midazolam, and sevoflurane in dogs

OBJECTIVE

To report serum cardiac troponin I (cTnI) and C-reactive protein (CRP) concentrations in dogs anesthetized for elective surgery using two anesthetic protocols.

STUDY DESIGN

Prospective, randomized clinical study.

ANIMALS

Twenty client-owned dogs presenting for elective ovariohysterectomy or castration.

METHODS

The dogs were randomized into two groups. All dogs were premedicated with glycopyrrolate (0.011 mg kg(-1)) and hydromorphone (0.1 mg kg(-1)) i.m. approximately 30 minutes prior to induction of anesthesia. Anesthesia in dogs in group 1 was induced with propofol (6 mg kg(-1)) i.v. to effect and in dogs in group 2 with diazepam (0.2 mg kg(-1)) i.v. followed by etomidate (2 mg kg(-1)) i.v. to effect. For maintenance of anesthesia, group 1 received sevoflurane (adjustable vaporizer setting 0.5-4%) and group 2 received a combination of fentanyl (0.8 microg kg(-1) minute(-1)) and midazolam (8.0 microg kg(-1) minute(-1)) i.v. plus sevoflurane (adjustable vaporizer setting 0.5-4%) to maintain anesthesia. Serum cTnI and CRP concentrations were measured at baseline and 6, 18, and 24 hours post-anesthetic induction. Biochemical analysis was performed at baseline. Lactate was obtained at baseline and 6 hours post-anesthetic induction. Heart rate and mean arterial blood pressure were measured intra-operatively.

RESULTS

Baseline serum cTnI and CRP concentrations were comparable between groups. A significant difference in serum cTnI or CRP concentrations was not detected post-operatively between groups at any time point. Serum CRP concentrations were significantly increased post-anesthetic induction in both groups, which was attributed to surgical trauma.

CONCLUSIONS AND CLINICAL RELEVANCE

There was no significant difference in serum cTnI and CRP concentrations between anesthetic protocols. Further investigation in a larger number of dogs is necessary to confirm the current findings.

Organ protection by volatile anesthetics in non-coronary artery bypass grafting surgery

The cardioprotective properties of volatile anesthetics have been widely demonstrated by numerous randomized studies and meta-analyses in the setting of cardiac surgery, above of all during coronary artery bypass grafting procedures. Recently, conflicting results have been presented in cardiac non-coronary artery bypass grafting surgery. Unfortunately, despite the existence of a great number of studies comparing a total intravenous anesthetic regimen with an inhalational regimen, at present there are no randomized studies presenting data regarding mortality and important outcomes, such as myocardial infarction, in non-cardiac surgery. In this review we analyze and present the results of the most recent and important studies regarding anesthetic preconditioning in cardiac and in noncardiac surgery. Furthermore, we focus on the emerging data from animal experiments, discussing in particular the molecular mechanisms underlying anesthetic preconditioning.