Does dexmedetomidine provide cardioprotection in coronary artery bypass grafting with cardiopulmonary bypass? A pilot study

Effectiveness of Dexmedetomidine as Myocardial Protector in Children With Classic Tetralogy of Fallot Having Corrective Surgery: A Randomized Controlled Trial

OBJECTIVES

Efficacy of dexmedetomidine (DEX) as a cardioprotective agent in Indonesian children undergoing classic tetralogy of Fallot (TOF) repair with cardiopulmonary bypass (CPB).

DESIGN

A prospective, parallel trial using block randomization along with double-blinded preparation of treatment agents by other parties.

SETTING

National Cardiovascular Center Harapan Kita, Indonesia.

PARTICIPANTS

Sixty-six children with classic TOF scheduled for corrective surgery. No children were excluded. All patients had fulfilled the criteria for analysis.

INTERVENTIONS

A total of 0.5 µg/kg bolus of DEX was added to the CPB priming solution, followed by 0.25 µg/kg/h maintenance during bypass. The placebo group used normal saline. Follow-ups were up to 30 days.

MEASUREMENTS AND MAIN RESULTS

Troponin I was lower in the DEX group at 6 hours (30.48 ± 19.33 v 42.73 ± 27.16, p = 0.039) and 24 hours after CPB (8.89 ± 5.42 v 14.04 ± 11.17, p = 0.02). Within a similar timeframe, DEX successfully lowered interleukin-6 (p = 0.03; p = 0.035, respectively). Lactate was lower in the Dex group at 1, 6, and 24 hours after CPB (p < 0.01; p = 0.048; p = 0.035; respectively). Dexmedetomidine increased cardiac output and index from 6 hours after bypass, but vice versa in systemic vascular resistance. Reduction of vasoactive inotropic score was seen during intensive care unit monitoring in the Dex group (p = 0.049). Nevertheless, DEX did not significantly affect the length of ventilation (p = 0.313), intensive care unit stay (p = 0.087), and mortality (p > 0.99).

CONCLUSIONS

Dexmedetomidine during CPB is an effective cardioprotective agent in TOF children having surgery. Postoperative mortality was comparable across groups.

Dexmedetomidine as a cardioprotective drug: a narrative review

Dexmedetomidine (DEX), a highly selective alpha2-adrenoceptors agonist, is not only a sedative drug used during mechanical ventilation in the intensive care unit but also a cardio-protective drug against ischemia-reperfusion injury (IRI). Numerous preclinical in vivo and ex vivo studies, mostly evaluating the effect of DEX pretreatment in healthy rodents, have shown the efficacy of DEX in protecting the hearts from IRI. However, whether DEX can maintain its cardio-protective effect in hearts with comorbidities such as diabetes has not been fully elucidated. Multiple clinical trials have reported promising results, showing that pretreatment with DEX can attenuate cardiac damage in patients undergoing cardiac surgery. However, evidence of the post-treatment effects of DEX in clinical practice remains limited. In this narrative review, we summarize the previously reported evidence of DEX-induced cardio-protection against IRI and clarify the condition of the hearts and the timing of DEX administration that has not been tested. With further investigations evaluating these knowledge gaps, the use of DEX as a cardio-protective drug could be further facilitated in the management of patients undergoing cardiac surgery and might be considered in a broader area of clinical settings beyond cardiac surgery, including patients with acute myocardial infarction.

Effects of interventions targeting the systemic inflammatory response to cardiac surgery on clinical outcomes in adults

BACKGROUND

Organ injury is a common and severe complication of cardiac surgery that contributes to the majority of deaths. There are no effective treatment or prevention strategies. It has been suggested that innate immune system activation may have a causal role in organ injury. A wide range of organ protection interventions targeting the innate immune response have been evaluated in randomised controlled trials (RCTs) in adult cardiac surgery patients, with inconsistent results in terms of effectiveness.

OBJECTIVES

The aim of the review was to summarise the results of RCTs of organ protection interventions targeting the innate immune response in adult cardiac surgery. The review considered whether the interventions had a treatment effect on inflammation, important clinical outcomes, or both.

SEARCH METHODS

CENTRAL, MEDLINE, Embase, conference proceedings and two trial registers were searched on October 2022 together with reference checking to identify additional studies.

SELECTION CRITERIA

RCTs comparing organ protection interventions targeting the innate immune response versus placebo or no treatment in adult patients undergoing cardiac surgery where the treatment effect on innate immune activation and on clinical outcomes of interest were reported.

DATA COLLECTION AND ANALYSIS

Searches, study selection, quality assessment, and data extractions were performed independently by pairs of authors. The primary inflammation outcomes were peak IL-6 and IL-8 concentrations in blood post-surgery. The primary clinical outcome was in-hospital or 30-day mortality. Treatment effects were expressed as risk ratios (RR) and standardised mean difference (SMD) with 95% confidence intervals (CI). Meta-analyses were performed using random effects models, and heterogeneity was assessed using I2.

MAIN RESULTS

A total of 40,255 participants from 328 RCTs were included in the synthesis. The effects of treatments on IL-6 (SMD -0.77, 95% CI -0.97 to -0.58, I2 = 92%) and IL-8 (SMD -0.92, 95% CI -1.20 to -0.65, I2 = 91%) were unclear due to heterogeneity. Heterogeneity for inflammation outcomes persisted across multiple sensitivity and moderator analyses. The pooled treatment effect for in-hospital or 30-day mortality was RR 0.78, 95% CI 0.68 to 0.91, I2 = 0%, suggesting a significant clinical benefit. There was little or no treatment effect on mortality when analyses were restricted to studies at low risk of bias. Post hoc analyses failed to demonstrate consistent treatment effects on inflammation and clinical outcomes. Levels of certainty for pooled treatment effects on the primary outcomes were very low.

AUTHORS' CONCLUSIONS

A systematic review of RCTs of organ protection interventions targeting innate immune system activation did not resolve uncertainty as to the effectiveness of these treatments, or the role of innate immunity in organ injury following cardiac surgery.

Dexmedetomidine as an anesthetic adjunct is associated with reduced complications and cardiac intensive care unit length of stay after heart valve surgery

BACKGROUND

We sought to explore the relationship between dexmedetomidine as an anesthetic adjuvant in cardiac surgery and postoperative complications and length of stay (LOS) in the cardiac intensive care unit (CICU).

METHODS

We conducted a retrospective study of patients aged 18 years and older who underwent heart valve surgery between October 2020 and June 2022. The primary endpoint of the study was major postoperative complications (cardiac arrest, atrial fibrillation, myocardial injury/infarction, heart failure) and the secondary endpoint was prolonged CICU LOS (defined as LOS > 90th percentile). Multivariate logistic regression analysis was performed for variables that were significant in the univariate analysis.

RESULTS

A total of 856 patients entered our study. The 283 patients who experienced the primary and secondary endpoints were included in the adverse outcomes group, and the remaining 573 were included in the prognostic control group. Multivariate logistic regression analysis revealed that age > 60 years (odds ratio [OR], 1.68; 95% confidence interval [CI], 1.23-2.31; p < 0.01), cardiopulmonary bypass (CPB) > 180 min (OR, 1.62; 95% CI, 1.03-2.55; p = 0.04) and postoperative mechanical ventilation time > 10 h (OR, 1.84; 95% CI, 1.35-2.52; p < 0.01) were independent risk factors for major postoperative complications; Age > 60 years (OR, 3.20; 95% CI, 1.65-6.20; p < 0.01), preoperative NYHA class 4 (OR, 4.03; 95% CI, 1.74-9.33; p < 0.01), diabetes mellitus (OR, 2.57; 95% CI, 1.22-5.41; p = 0.01), Intraoperative red blood cell (RBC) transfusion > 650 ml (OR, 2.04; 95% CI, 1.13-3.66; p = 0.02), Intraoperative bleeding > 1200 ml (OR, 2.69; 95% CI, 1.42-5.12; p < 0.01) were independent risk factors for prolonged CICU length of stay. Intraoperative use of dexmedetomidine as an anesthetic adjunct was a protective factor for major complications (odds ratio, 0.51; 95% confidence interval, 0.35-0.74; p < 0.01) and prolonged CICU stay. (odds ratio, 0.37; 95% confidence interval, 0.19-0.73; p < 0.01).

CONCLUSIONS

In patients undergoing heart valve surgery, age, duration of cardiopulmonary bypass, and duration of mechanical ventilation are associated with major postoperative complication. Age, preoperative NYHA classification 4, diabetes mellitus, intraoperative bleeding, and RBC transfusion are associated with increased CICU length of stay. Intraoperative use of dexmedetomidine may improve such clinical outcomes.

Dexmedetomidine for adult cardiac surgery: a systematic review, meta-analysis and trial sequential analysis

The effects of dexmedetomidine in adults undergoing cardiac surgery are inconsistent. We conducted a systematic review and meta-analysis to analyse the effects of peri-operative dexmedetomidine in adults undergoing cardiac surgery. We searched MEDLINE via Pubmed, EMBASE, Scopus and Cochrane for relevant randomised controlled trials between 1 January 1990 and 1 March 2022. We used the Joanna Briggs Institute methodology checklist to assess study quality and the GRADE approach to certainty of evidence. We assessed the sensitivity of results to false data. We used random-effects meta-analyses to analyse the primary outcomes: durations of intensive care and tracheal intubation. We included 48 trials of 6273 participants. Dexmedetomidine reduced the mean (95%CI) duration of intensive care by 5.0 (2.2-7.7) h, p = 0.001, and tracheal intubation by 1.6 (0.6-2.7) h, p = 0.003. The relative risk (95%CI) for postoperative delirium was 0.58 (0.43-0.78), p = 0.001; 0.76 (0.61-0.95) for atrial fibrillation, p = 0.015; and 0.49 (0.25-0.97) for short-term mortality, p = 0.041. Bradycardia and hypotension were not significantly affected. Trial sequential analysis was consistent with the primary meta-analysis. Adjustments for possible false data reduced the mean (95%CI) reduction in duration of intensive care and tracheal intubation by dexmedetomidine to 3.6 (1.8-5.4) h and 0.8 (0.2-1.4) h, respectively. Binary adjustment for methodological quality at a Joanna Briggs Institute score threshold of 10 did not alter the results significantly. In summary, peri-operative dexmedetomidine reduced the durations of intensive care and tracheal intubation and the incidence of short-term mortality after adult cardiac surgery. The reductions in intensive care stay and tracheal intubation may or may not be considered clinically useful, particularly after adjustment for possible false data.

Effect of Dexmedetomidine on Cardiac Surgery Patients

ABSTRACT

Dexmedetomidine, an alpha-2 adrenoreceptor agonist that is widely used as a sedative medication, is becoming more and more attractive in clinical application on cardiac surgery patients. In this review, we aim to summarize and discuss both retrospective studies and clinical trials regarding the effect of dexmedetomidine on patients who underwent cardiac surgery (including coronary artery bypass grafting, valve surgery, aortic surgery, percutaneous coronary intervention, and so on), which illustrates that the clinical effects of dexmedetomidine could effectively reduce mortality, major complications, and the intensive care unit and hospital length of stay without comprising safety. In addition, inconsistent results from both retrospective studies and clinical trials have also been demonstrated. Although the effectiveness and safety of dexmedetomidine on cardiac surgery patients is suggested, high-quality clinical trials are needed for further verification.

High-Sensitivity Cardiac Troponin I and T Kinetics Differ following Coronary Bypass Surgery: A Systematic Review and Meta-Analysis

Background

Cardiac troponin I and T are both used for diagnosing myocardial infarction (MI) after coronary artery bypass grafting (CABG), also known as type 5 MI (MI-5). Different MI-5 definitions have been formulated, using multiples of the 99th percentile upper reference limit (10×, 35×, or 70× URL), with or without supporting evidence. These definitions are arbitrarily chosen based on conventional assays and do not differentiate between troponin I and T. We therefore investigated the kinetics of high-sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) following CABG.

Methods

A systematic search was applied to MEDLINE and EMBASE databases including the search terms “coronary artery bypass grafting” AND “high-sensitivity cardiac troponin.” Studies reporting hs-cTnI or hs-cTnT on at least 2 different time points were included. Troponin concentrations were extracted and normalized to the assay-specific URL.

Results

For hs-cTnI and hs-cTnT, 17 (n = 1661 patients) and 15 studies (n = 2646 patients) were included, respectively. Preoperative hs-cTnI was 6.1× URL (95% confidence intervals: 4.9–7.2) and hs-cTnT 1.2× URL (0.9–1.4). Mean peak was reached 6–8 h postoperatively (126× URL, 99–153 and 45× URL, 29–61, respectively). Subanalysis of hs-cTnI illustrated assay-specific peak heights and kinetics, while subanalysis of surgical strategies revealed 3-fold higher hs-cTnI than hs-cTnT for on-pump CABG and 5-fold for off-pump CABG.

Conclusion

Postoperative hs-cTnI and hs-cTnT following CABG surpass most current diagnostic cutoff values. hs-cTnI was almost 3-fold higher than hs-cTnT, and appeared to be highly dependent on the assay used and surgical strategy. There is a need for assay-specific hs-cTnI and hs-cTnT cutoff values for accurate, timely identification of MI-5.

Effects of dexmedetomidine on cardioprotection and other postoperative complications in elderly patients after cardiac and non-cardiac surgerie

BACKGROUND

After cardiac and non-cardiac surgeries, elderly patients have a high probability of developing cardiac complications and postoperative delirium. Although several clinical trials have investigated whether perioperative intravenous dexmedetomidine can protect the heart and reduce postoperative complications such as delirium in elderly patients, the obtained results have been inconsistent. We conducted a meta-analysis to investigate the effects of dexmedetomidine on cardioprotection and other postoperative complications in elderly patients undergoing cardiac or non-cardiac surgery.

AIM

To investigate the effects of dexmedetomidine on cardiac complications and delirium in elderly patients undergoing cardiac or non-cardiac surgery.

METHODS

The PubMed, Cochrane Library, web of science, and other sources were comprehensively searched for all randomized controlled trials published before May 2021 that investigated the efficacy of dexmedetomidine in the prevention of cardiac and postoperative delirium (POD).

RESULTS

In total, 18 studies involving 1025 patients were included in the meta-analysis. Intravenous dexmedetomidine significantly reduced cardiac troponin I (cTnI) and the inflammatory factor tumor necrosis factor-α (TNF-α) was comparable to the control group. Dexmedetomidine also reduced the POD and mortality rates. However, patients in the dexmedetomidine group were more likely to have a decreased heart rate (within the normal range) and hypotension during dexmedetomidine administration than those in the control group. There was no difference in the occurrence of myocardial infarction, bradycardia, or stroke between the two groups. Dexmedetomidine significantly shortened the time to extubate; however, it did not shorten the length of stay in the intensive care unit.

CONCLUSION

The administration of dexmedetomidine during cardiac and non-cardiac surgeries can provide myocardial protection by inhibiting inflammation and cTnI, which may be beneficial for the rapid recovery of patients. Meanwhile, the administration of dexmedetomidine reduced the incidence of POD and decreased mortality (in-hospital).

Meta-Analysis Evaluating High-Sensitivity Cardiac Troponin T Kinetics after Coronary Artery Bypass Grafting in Relation to the Current Definitions of Myocardial Infarction

Various definitions of myocardial infarction type 5 after coronary artery bypass grafting (CABG) have been proposed (myocardial infarction [MI-5], also known as peri-procedural MI), using different biomarkers and different and arbitrary cut-off values. This meta-analysis aims to determine the expected release of high-sensitivity cardiac troponin T (hs-cTnT) after CABG in general and after uncomplicated surgery and off-pump CABG in particular. A systematic search was applied to 3 databases. Studies on CABG as a single intervention and reporting on postoperative hs-cTnT concentrations on at least 2 different time points were included. All data on hs-cTnT concentrations were extracted, and mean concentrations at various points in time were stratified. Eventually, 15 studies were included, encompassing 2,646 patients. Preoperative hs-cTnT was 17 ng/L (95% confidence interval [CI] 13 to 20 ng/L). Hs-cTnT peaked at 6 to 8 hours postoperatively (628 ng/L, 95% CI 400 to 856 ng/L; 45x upper reference limit [URL]) and was still increased after 48 hours. In addition, peak hs-cTnT concentration was 614 ng/L (95% CI 282 to 947 ng/L) in patients with a definite uncomplicated postoperative course (i.e., without MI). For patients after off-pump CABG compared to on-pump CABG, the mean peak hs-cTnT concentration was 186 ng/L (95% CI 172 to 200 ng/L, 13 × URL) versus 629 ng/L (95% CI 529 to 726 ng/L, 45 × URL), respectively. In conclusion, postoperative hs-cTnT concentrations surpass most of the currently defined cut-off values for MI-5, even in perceived uncomplicated surgery, suggesting thorough reassessment. Hs-cTnT release differences following on-pump CABG versus off-pump CABG were observed, implying the need for different cut-off values for different surgical strategies.

Post-operative Non-sustained Ventricular Tachycardia in a COVID-19 Positive Patient After Ketamine and Dexmedetomidine Infusion

We present a case of an elderly, 75-year-old gentleman with COVID-19 infection and a permanent pacemaker in place, presenting for elective procedure, under monitored anesthesia care with dexmedetomidine. In the postoperative period, while still in the Post Anesthesia Care Unit (PACU), the patient became unresponsive and was found to have episodes of arrhythmia. The patient was managed in the PACU by the anesthesia team. To date, our report is the only one addressing cardiac complications in elderly patients with preexisting cardiac comorbidity, in the immediate perioperative period.

Myocardial protective and anti-inflammatory effects of dexmedetomidine in patients undergoing cardiovascular surgery with cardiopulmonary bypass: a systematic review and meta-analysis

Cardiopulmonary bypass (CPB) technology provides potential for cardiac surgery, but it is followed by myocardial injury and inflammation related to ischemia–reperfusion. This meta-analysis aimed to systematically evaluate the cardioprotective effect of dexmedetomidine on cardiac surgery under CPB and its effect on accompanied inflammation. PubMed, Cochrane Library, EMBASE and Web of Science databases were comprehensively searched for all randomized controlled trials (RCTs) published before April 1st, 2021 that explored the application of dexmedetomidine in cardiac surgery. Compared with the control group (group C), the concentrations of CK-MB in the perioperative period and cTn-I at 12 h and 24 h after operation in dexmedetomidine group (group D) were significantly decreased (P < 0.05). In addition, in group D, the levels of interleukin-6 at 24 h after operation, tumor necrosis factor-a at the 12 h and 24 h after operation were significantly decreased (P < 0.05). At the same time, the length of Intensive Care Unit stay in group D was significantly shorter than group C (P < 0.05). However, there was no significant difference in interleukin-10 level, C reactive protein level, the time on ventilator and length of hospital stay between the two groups (P > 0.05). The application of dexmedetomidine in cardiac surgery with CPB can reduce CK-MB and cTn-I concentration and interleukin-6, tumor necrosis factor-α levels to a certain extent and shorten the length of Intensive Care Unit stay, but it has no significant effect on IL-10 level, C reactive protein level, the time on ventilator and length of hospital stay.

Cardioprotective effects of propofol-dexmedetomidine in open-heart surgery: A prospective double-blind study

Background:

Myocardial protection in cardiac surgeries is a must and requires multimodal approaches in perioperative period to decrease and prevent the increase of myocardial oxygen demand and consumption that lead to postoperative cardiac complications including myocardial ischemia, dysfunction, and heart failure.

Study Design:

Prospective, controlled, randomized, double-blinded study.

Aims:

This study aims to study the effect of propofol-dexmedetomidine continuous infusion cardioprotection during open-heart surgery in adult patients.

Materials and Methods:

Sixty adult patients of both sexes aged from 30 to 60 years old belonging to the American Society of Anesthesiologists III or IV undergoing open-heart surgery were randomly divided into two equal groups: Group P (control group) received continuous infusion of propofol at a rate of 2 mg/kg/h and 50 cc 0.9% sodium chloride solution infused at a rate of 0.4 μg/kg/h (used as a placebo) and Group PD received continuous infusion of propofol at a rate of 2 mg/kg/h and dexmedetomidine 200 μg diluted in 50 cc 0.9% sodium chloride solution infused at a rate of 0.4 μg/kg/h. Infusion for all patients started immediately preoperative till skin closure. Hemodynamic measurements of heart rate (HR), invasive mean arterial pressure, and oxygen saturation were recorded at baseline before induction of anesthesia, immediately after intubation, at skin incision, at sternotomy and every 15 min in the 1^st h then every 30 min during the prebypass period then every 15 min in the 1^st h then every 30 min after weaning from CPB till the end of the surgery. Serum biomarkers; cardiac troponin (cTnI) and creatine kinase-myocardial bound (CK-MB) samples were measured basally (T1), 15 min after unclamping of the aorta (T2), immediate postoperative (T3), and 24 h postoperative (T4). Intraoperative data were also recorded including the number of coronary grafts, aortic cross-clamping duration, duration of cardiopulmonary bypass (CPB), duration of surgery, and rhythm of reperfusion. Fentanyl requirement, extubation time, and length of intensive care unit (ICU) stay were also recorded for every case.

Results:

There was no statistically significant differences as regard to demographic data between the studied two groups. HR and blood pressure recorded was lower in the PD group than the control group, and this difference was noted to be statistically significant. Furthermore, the PD group showed lower levels of myocardial enzymes (cTnI and CK-MB), decreased total fentanyl requirement, earlier postoperative extubation, and shorter ICU stay than the P (control) group.

Conclusion:

The use of propofol-dexmedetomidine in CPB surgeries offers more cardioprotective effects than the use of propofol alone.

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.

Perioperative Cardioprotection: Clinical Implications

Perioperative cardioprotection aims to minimize the consequences of myocardial ischemia-reperfusion injury. In isolated tissue and animal experiments, several treatments have been identified providing cardioprotection. Some of these strategies have been confirmed in clinical proof-of-concept studies. However, the final translation of cardioprotective strategies to really improve clinical outcome has been disappointing: large randomized controlled clinical trials mostly revealed inconclusive, neutral, or negative results. This review provides an overview of the currently available evidence regarding clinical implications of perioperative cardioprotective therapies from an anesthesiological perspective, highlighting nonpharmacological as well as pharmacological strategies. We discuss reasons why translation of promising experimental results into clinical practice and outcome improvement is hampered by potential confounders and suggest future perspectives to overcome these limitations.

Effects of Pre-Cardiopulmonary Bypass Administration of Dexmedetomidine on Cardiac Injuries and the Inflammatory Response in Valve Replacement Surgery With a Sevoflurane Postconditioning Protocol: A Pilot Study

Supplemental Digital Content is Available in the Text.

Background:

Preventing myocardial ischemia–reperfusion injury in on-pump cardiac surgeries remains an enormous challenge. Sevoflurane postconditioning has been effective at overcoming this challenge by modulating inflammatory mediators and ameliorating antioxidative stress. Dexmedetomidine (DEX) is a commonly used medication for cardiac patients with organ-protective properties that lead to positive outcomes. Whether DEX also has cardiac-protective properties and the associated mechanism in sevoflurane postconditioning–based valve replacement surgeries are unknown.

Objective:

This study was conducted to observe the effect of DEX administration before cardiopulmonary bypass (CPB) on myocardial injury, oxidative stress, and inflammatory response indicators in the peripheral blood.

Methods:

Twenty-eight eligible cardiac patients who underwent valve replacement surgery with standard sevoflurane postconditioning were included in the study. The patients were randomly divided into a DEX group and a non-DEX group according to whether DEX (0.5-µg/kg overload dose for 10 minutes and a 0.5-μg/kg/h maintenance dose) or saline was administered from induction to the beginning of CPB. The primary outcome was the cardiac troponin I concentration (cTnI) in the blood 24 hours after CPB. The levels of malondialdehyde (MDA), superoxide dismutase, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8) were also measured.

Results:

The mean cTnI at 24 hours after CPB was clearly decreased in the DEX group compared with that in the non-DEX group (4.16 ± 1.58 vs. 6.90 ± 3.73, P < 0.05). TNF-α levels were lower in the DEX group after CPB (T1–T5), with a significant difference found at 1–6 hours after CPB (1 hour, 19.03 vs. 28.09; 6 hours, 20.74 vs. 30.94, P < 0.05). The IL-6 and IL-8 concentrations in the DEX group were dramatically increased at 6 hours after CPB (P < 0.05). The MDA content and superoxide dismutase activity were comparable between the 2 groups. A lower proportion of anemia cases were noted after CPB in the DEX group than in the non-DEX group (non-DEX, 10% vs. DEX, 5%, P < 0.05).

Conclusions:

In valve replacement surgery with sevoflurane postconditioning, pre-CPB administration of DEX can reduce the cTnI level at 24 hours after CPB and brings synergic benefits of the inflammatory response.

Pre-cardiopulmonary bypass administration of dexmedetomidine decreases cardiac troponin I level following cardiac surgery with sevoflurane postconditioning

Objective

This study was performed to determine the effect of dexmedetomidine (DEX) administration on myocardial damage in cardiac surgery with sevoflurane postconditioning.

Methods

We retrospectively examined all cardiac valve replacement surgeries from 1 April 2016 to 30 April 2017. Eligible patients were divided into two groups based on whether DEX was infused. DEX infusion was permitted only between intubation and the beginning of cardiopulmonary bypass (CPB). Sevoflurane was inhaled via the standard postconditioning procedure starting at aortic declamping. The cardiac troponin I (cTnI) level was measured at different time points. The postoperative outcomes and complications were also analyzed.

Results

One hundred patients were included in the study (DEX group, n = 53; non-DEX group, n = 47). Increased cTnI levels were significantly correlated with the New York Heart Association classification, CPB time, and DEX use. DEX use and the CPB time were potential independent factors contributing to changes in the cTnI level. The cTnI level at 6, 12, and 24 hours postoperatively was remarkably lower in the DEX than non-DEX group by 1.14, 7.83, and 5.86 ng/mL, respectively.

Conclusions

DEX decreased the cTnI level after CPB when sevoflurane postconditioning was used, especially at 6, 12, and 24 hours postoperatively.

The efficacy and safety of dexmedetomidine in cardiac surgery patients: A systematic review and meta-analysis

This study aimed to evaluate the efficacy and safety of dexmedetomidine versus any other treatment without dexmedetomidine in patients who have undergone cardiac surgery. Electronic databases including PubMed, Embase, and Cochrane Library were systematically searched without limitations of language and publication time. Randomized controlled trials (RCTs) aiming to evaluate the efficacy and safety of dexmedetomidine versus any other treatment without dexmedetomidine in patients that have undergone cardiac surgery were selected. Endpoints such as hemodynamic indexes and adverse events in eligible studies were extracted by two researchers, independently. The data was analyzed using RevMan 5.3 and Stata 11.0 software. A total of 18 RCTs met the inclusion criteria, involving 1730 patients. Compared to control (any treatment without dexmedetomidine), dexmedetomidine showed a pooled mean difference (MD) of -14.46 [95% confidence interval(CI): -24.69, -4.23; p<0.01] for systolic arterial pressure, a standardized mean difference (SMD) of -1.74 for mean arterial blood pressure (95% CI: -2.80, -0.68; P < 0.01), -2.12 (95%CI: -3.23, -1.00; p<0.01) for heart rate, and combined odds ratio (OR) of 0.22 (95%CI: 0.11, 0.44; p<0.01) for tachycardia, 3.44 (95%CI: 1.95, 5.96; p<0.01) for bradycardia, 0.74 (95%CI: 0.49, 1.12; p>0.05) for atrial fibrillation, and 0.99 (95%CI: 0.51, 1.90; p>0.05) for hypotension. In addition, dexmedetomidine could reduce time of surgery and stay in intensive care units, improve delirium with good safety. Our study shows clinical application of dexmedetomidine in cardiac surgery patients can reduce risks of abnormal hemodynamics with good safety.

A Comparative Study Evaluating Effects of Intravenous Sedation by Dexmedetomidine and Propofol on Patient Hemodynamics and Postoperative Outcomes in Cardiac Surgery

Background

The use of intravenous sedation during cardiac surgery to reduce awareness has been practised routinely during past few years and the two most commonly used drugs include propofol and dexmedetomidine, but their effects on hemodynamics and postoperative outcomes in cardiac surgery is continually being evaluated.

Aims

The aim of this study was to compare the effects of anesthesia by dexmedetomidine and propofol on the hemodynamic variables and postoperative outcomes in patients who were planned for elective cardiac surgery.

Settings

Cardiac operating room of a tertiary care hospital.

Design

A prospective, randomized controlled, double-blind clinical trial.

Materials and Methods

Sixty patients were randomized to receive either a continuous infusion of propofol (0.25-1 mg/kg/h) or dexmedetomidine bolus of 1 μg/kg over 10 min followed by infusion (0.2-0.6 μg/kg/h) after induction of anesthesia. The anesthesia technique and physiological monitoring including bispectral index monitoring were similar among both the groups. Hemodynamic variables (mean heart rate [HR], mean arterial pressure [MAP]) were noted at predefined time intervals, intraoperative vasopressor or inotrope requirements and postoperative outcomes including postoperative ventilation time and length of stay in the Intensive Care Unit (ICU) were also recorded.

Statistical Analysis

Statistics was done using SPSS V 20 (IBM, NY) using Student's t-test, analysis of variance, and Mann-Whitney U-test, and a P < 0.05 was considered to indicate a significant difference.

Results and Conclusions

HR and MAP were significantly less in dexmedetomidine group compared to propofol group (P < 0.05). Both the groups had a similar requirement of vasopressors and inotropes. The duration of postoperative ventilation and length of stay in the ICU were significantly shorter in the dexmedetomidine group (P < 0.05). The risk of delirium was significantly less in dexmedetomidine group (P < 0.05). From our study we concluded, that the perioperative infusion of dexmedetomidine produces better hemodynamic stability, reduces the risk of postoperative delirium, and leads to shorter ICU stay.

Myocardial protective effects of dexmedetomidine in patients undergoing cardiac surgery: A meta-analysis and systematic review

Arrhythmias are the common complications following cardiac surgery and contribute to hemodynamic instability, cognitive impairment, thromboembolic events, and congestive heart failure. Prevention of atrial fibrillation following cardiac surgery reduces morbidity and among the many available preventive approaches dexmedetomidine shows many positive effects on cardiovascular stability. Even though many studies indicated the beneficial effects of dexmedetomidine, the power of the analysis and conclusion of these studies is rather weak due to relatively smaller number of patients in these studies. In the present meta-analysis, we included a large number of patients, both children and adults, undergoing cardiac surgery, to address the efficacy of dexmedetomidine. Several databases were searched to identify clinical studies comparing the efficacy of dexmedetomidine in myocardial protection in patients undergoing cardiac surgery. Cardiac function related parameters including heart rate, blood pressure, tachycardia, arrhthmias, and bradycardia were measured. In accordance with the selection criteria, a total of 18 studies published between 2003 and 2016, with a total of 19,225 patients were included in the present meta-analysis. Dosage of dexmedetomidine was in the range of 0.5-1 µg/kg body weight loading followed by continuous infusion at a rate of 0.2-0.7 µg/kg/h. Dexmedetomidine treatment was found to lower heart rate, systolic blood pressure, incidence of tachycardia and arrhythmias in both adult and pediatric patients, but elevated the risk of bradycardia. In conclusion, results of this meta-analysis indicate that dexmedetomidine is an efficacious cardioprotective drug in adults and children undergoing cardiac surgery.

The Influence of Perioperative Dexmedetomidine on Patients Undergoing Cardiac Surgery: A Meta-Analysis

Background

The use of dexmedetomidine may have benefits on the clinical outcomes of cardiac surgery. We conducted a meta-analysis comparing the postoperative complications in patients undergoing cardiac surgery with dexmedetomidine versus other perioperative medications to determine the influence of perioperative dexmedetomidine on cardiac surgery patients.

Methods

Randomized or quasi-randomized controlled trials comparing outcomes in patients who underwent cardiac surgery with dexmedetomidine, another medication, or a placebo were retrieved from EMBASE, PubMed, the Cochrane Library, and Science Citation Index.

Results

A total of 1702 patients in 14 studies met the selection criteria among 1,535 studies that fit the research strategy. Compared to other medications, dexmedetomidine has combined risk ratios of 0.28 (95% confidence interval [CI] 0.15, 0.55, P = 0.0002) for ventricular tachycardia, 0.35 (95% CI 0.20, 0.62, P = 0.0004) for postoperative delirium, 0.76 (95% CI 0.55, 1.06, P = 0.11) for atrial fibrillation, 1.08 (95% CI 0.74, 1.57, P = 0.69) for hypotension, and 2.23 (95% CI 1.36, 3.67, P = 0.001) for bradycardia. In addition, dexmedetomidine may reduce the length of intensive care unit (ICU) and hospital stay.

Conclusions

This meta-analysis revealed that the perioperative use of dexmedetomidine in patients undergoing cardiac surgery can reduce the risk of postoperative ventricular tachycardia and delirium, but may increase the risk of bradycardia. The estimates showed a decreased risk of atrial fibrillation, shorter length of ICU stay and hospitalization, and increased risk of hypotension with dexmedetomidine.

Neuroprotective Effects of Dexmedetomidine Against Hypoxia-Induced Nervous System Injury are Related to Inhibition of NF-κB/COX-2 Pathways

Dexmedetomidine has been reported to provide neuroprotection against hypoxia-induced damage. However, the underlying mechanisms remain unclear. We examined whether dexmedetomidine's neuroprotective effects were mediated by the NF-κB/COX-2 pathways. Adult male C57BL/6 mice were subjected to a 30-min hypoxic treatment followed by recovery to normal conditions. They received dexmedetomidine (16 or 160 μg/kg) or 25 mg/kg atipamezole, an α2-adrenoreceptor antagonist, intraperitoneally before exposure to hypoxia. The whole brain was harvested 6, 18, or 36 h after the hypoxia to determine the histopathological outcome and cleaved caspase-3, Bax/Bcl, NF-κB, and COX-2 levels. Hypoxia treatment induced significant neurotoxicity, including destruction of the tissue structure and upregulation of the protein levels of caspase-3, the ratio of Bax/Bcl-2, NF-κB, and COX-2. Dexmedetomidine pretreatment effectively improved histological outcome and restored levels of caspase-3, the Bax/Bcl-2 ratio, NF-κB, and COX-2. Atipamezole reversed the neuroprotection induced by dexmedetomidine. Neuroprotection was achieved by PDTC and NS-398, inhibitors of NF-κB and COX-2, respectively. Dexmedetomidine use before hypoxia provides neuroprotection. Inhibition of NF-κB/COX-2 pathways activation may contribute to the neuroprotection of dexmedetomidine.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.