Dexmedetomidine prevents acute kidney injury after adult cardiac surgery: a meta-analysis of randomized controlled trials

Perioperative dexmedetomidine for the prevention of postoperative delirium after cardiac surgery: a systematic review, Bayesian meta-analysis, and Bayesian re-analysis of the DECADE trial

BACKGROUND

Dexmedetomidine is seen as a promising agent for the prevention of postoperative delirium after cardiac surgery, but the largest study (DECADE) paradoxically suggested an increased risk of delirium.

METHODS

Studies were selected using inclusion/exclusion criteria after conducting online database searches for randomised controlled trials. The primary outcome was the incidence of postoperative delirium with a minimum clinically important difference (MCID), defined as an odds ratio >1.20 or <0.84. Publication bias was quantified using Bayesian model averaging. A random-effects meta-analysis with weakly informative priors was performed. Bayesian re-analysis of DECADE using several different priors including a prior based on this meta-analysis (excluding DECADE) was also performed.

RESULTS

We identified 12 eligible randomised controlled trials (3539 participants). The overall pooled effect showed a mean benefit from dexmedetomidine in delirium prevention (odds ratio 0.67 [95% credible interval 0.45, 0.92]), but any definitive evidence of benefit disappeared after accounting for publication bias (odds ratio 1.15 [95% credible interval 0.93, 2.51]). Bayesian re-analysis of the DECADE trial under a vague prior showed a 1.5% posterior probability of any benefit and only a 0.1% probability of an MCID for benefit. Combining DECADE with the unadjusted meta-analysis-derived prior increased the probability of an MCID for benefit to 17.8%, which decreased to 0.2% using the meta-analysis-derived prior adjusted for publication bias.

CONCLUSIONS

Pooled evidence suggests dexmedetomidine is associated with reduced incidence of postoperative delirium; however, this is highly sensitive to the possibility of publication bias. Bayesian re-analysis of the recently published DECADE trial showed the effect of dexmedetomidine differs markedly depending on the weight given to previous studies. Hence, any true benefit from the use of dexmedetomidine over standard care in this population cannot be definitively characterised at present.

SYSTEMATIC REVIEW PROTOCOL

CRD42023401623 (PROSPERO).

Impact of perioperative dexmedetomidine on long-term outcomes in older patients following cardiac surgery: follow-up of a randomized trial

BACKGROUND

Perioperative dexmedetomidine is reported to reduce complications and even in-hospital mortality after cardiac surgery. We therefore tested the hypothesis that perioperative dexmedetomidine may improve long-term outcomes after cardiac surgery.

METHODS

This was long-term follow-up of a randomized trial. We enrolled 285 patients aged 60 years or older who were scheduled for elective cardiac surgery. Patients were randomized to receive either dexmedetomidine or placebo (normal saline) during and early after surgery. Follow-up was conducted for up to 6 years post-surgery. The primary endpoint was overall survival. Secondary outcomes included major adverse cardiovascular events (MACE)-free and hospital-free survivals, as well as cognitive function and quality of life in 6-year survivors.

RESULTS

All 285 patients were included in final analysis. Median follow-up duration was 80 months (interquartile range 30 to 80). Overall survival did not differ between the two groups: there were 18 deaths (12.6%) with placebo versus 22 deaths (15.5%) with dexmedetomidine; hazard ratio (HR) 1.22, 95% CI 0.65 to 2.27, p = 0.418. MACE-free survival was 23 (16.1%) with placebo versus 24 (16.9%) with dexmedetomidine; HR 1.03, 95% CI 0.58 to 1.83, P = 0.911. Hospital-free survival was 39 (27.3%) with placebo versus 42 (29.6%) with dexmedetomidine; HR 1.04, 95% CI 0.67 to 1.61, P = 0.853. Among 6-year survivors, the scores of cognitive function and quality of life were similar between groups.

CONCLUSIONS

We found that, for older patients undergoing elective cardiac surgery, dexmedetomidine administered during and early after surgery did not alter overall and MACE-free survivals, as well as long-term cognitive function and quality of life. However, considering the underpowered sample size and non-negligible loss to follow-up rate, our results need further confirmation.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03289325 (September 20, 2017).

The effect of dexmedetomidine on acute kidney injury after elective major abdominal surgery : a retrospective single-center propensity score matched study

BACKGROUND

Major abdominal surgery is a kind of high-risk surgery type for postoperative acute kidney injury (AKI) among non-cardiac surgeries. Despite dexmedetomidine exerts significant renal protective effects in cardiac surgeries and animal studies, whether it is associated with a lower incidence of AKI in major abdominal surgeries remains unclear.

METHODS

From January 2019 to July 2021, patients undergoing elective major abdominal surgery in West China Hospital were enrolled. Participants were divided into two groups based on exposure to continuous intravenous dexmedetomidine: the Dex group (exposed) and the Control group (not exposed). The primary outcome was the incidence of AKI in the postoperative 7 days. Secondary outcomes included intraopertive average urine output, renal function on the first day after surgery, incidence of postoperative dialysis, postoperative intensive care unit (ICU) admission, in-hospital mortality, length of hospital stay, incidence of intraoperative hypotension and bradycardia, and intraoperative use of inotropes and vasopressors. Propensity score matching (PSM), based on participants' baseline and intraoperative characteristics, was performed to minimize potential bias. Furthermore, a subgroup analysis was conducted based on the infusion rate and the use of a loading dose to explore the effects of different methods of dexmedetomidine administration on AKI. The subgroups included: loading dose, non-loading dose, low-infusion rate (infusion rate ≤ 0.4 µg/kg/h), and high-infusion rate (infusion rate > 0.4 µg/kg/h).

RESULTS

After PSM with a ratio of 1:1, a total of 8836 patients were successfully matched. Dexmedetomidine administration had no association with the incidence of postoperative AKI, serum creatinine (Scr) level on the first postoperative day, incidence of postoperative dialysis, postoperative ICU admission, in-hospital mortality, length of hospital stay, intraoperative hypotension, or the use of inotropes and vasopressors, but had association with increased intraoperative average urine output (122.95 (76.80, 189.27) vs. 104.65 (67.04, 161.07) ml/h, P < 0.001), higher value of estimated glomerular filtration rate (eGFR) (97.33 ± 15.95 vs. 96.13 ± 16.35 ml/min/1.73m2, P < 0.001) on the first day after surgery and a higher incidence of intraoperative bradycardia (37.0% vs. 30.6%; P < 0.001). In the loading dose subgroup, dexmedetomidine use was significantly associated with a reduced incidence of postoperative AKI (odds ratio (OR): 0.44, 95% confidence interval (CI): 0.23-0.76, P = 0.006).The association between dexmedetomidine and postoperative AKI was absent in subgroups of high or low infusion rate and no loading dose use.

CONCLUSION

In this single-center retrospective propensity-matched study, we did not detect a significant overall difference in post-operative AKI rates between patients treated with or without dexmedetomidine during major abdominal surgery. However, though additional prospective data are needed, our study found that administering dexmedetomidine with a loading dose may be associated with lower rates of AKI, potentially indicating a renoprotective effect of loading-dose dexmedetomidine in this setting.

Effects of dexmedetomidine on renal function after cardiac surgery for infective endocarditis: An interim analysis of a randomized controlled trial

BACKGROUND

Patients undergoing cardiac surgery for infective endocarditis (IE) are at a high risk of postoperative acute kidney injury (AKI) owing to heightened systemic inflammation. Therefore, we aimed to investigate the effect of dexmedetomidine on postoperative AKI in patients who underwent cardiac surgery for IE.

METHODS

A total of 63 patients who underwent cardiac surgery for IE were randomly assigned to receive either intravenous dexmedetomidine infusion of 0.4 μg kg-1 h-1 (DEX group) or normal saline infusion (control group) for 24 h after induction of anesthesia. The occurrence of AKI within seven days postoperation, epinephrine, norepinephrine, and interleukin-6 levels, as well as postoperative morbidities, were assessed. An intertrim analysis was conducted using Pocock's alpha spending function at α = 0.05 and β = 0.2.

RESULTS

This trial was early terminated according to the results of interim analysis performed when 60 % of the pre-set number of patients have been collected. The incidence of AKI was significantly lower in the DEX group than in the control group (32.3 % vs. 9.4 %, p = 0.025). Patients in the DEX group had significantly lower epinephrine levels than those in the control group, whereas norepinephrine and interleukin-6 levels were similar. Perioperative mean arterial pressure or heart rate did not differ between the groups.

CONCLUSIONS

Dexmedetomidine administration for 24 h starting from induction of anesthesia significantly reduced the incidence of postoperative AKI after cardiac surgery for IE (by 29 % vs. control) without hemodynamic side effects. This was accompanied by a significant attenuation of postoperative increase in serum epinephrine levels.

Does dexmedetomidine reduce the risk of acute kidney injury after cardiac surgery? A meta-analysis of randomized controlled trials

BACKGROUND

Acute Kidney Injury (AKI) is a common complication after cardiac surgery and has been associated with poor outcomes. Dexmedetomidine (DEX) has been shown to confer direct renoprotection based on some animal and clinical studies, but data from other trials came to the opposite conclusion following cardiac surgery. This meta-analysis was conducted to evaluate the effects of perioperative DEX administration on the occurrence of AKI and the outcomes after cardiac surgery.

METHODS

We searched databases including EMBASE, PubMed, and Cochrane CENTRAL for Randomized Controlled Trials (RCTs) focused on DEX for AKI in adult patients after cardiac surgery. The primary outcome was incidence of AKI. Secondary outcomes were Mechanical Ventilation (MV) duration, Intensive Care Unit (ICU) Length Of Stay (LOS), hospital LOS and mortality.

RESULTS

Fifteen trials enrolling 2907 study patients were collected in the meta-analyses. Compared with controls, DEX reduced the incidence of postoperative AKI (Odds Ratio [OR = 0.66]; 95% Confidence Interval [95% CI 0.48-0.91]; p = 0.01), and there was no significant difference between groups in postoperative mortality (OR = 0.63; 95% CI 0.32-1.26; p = 0.19), MV duration (Weighted Mean Difference [WMD = -0.44]; 95% CI -1.50-0.63; p = 0.42), ICU LOS (WMD = -1.19; 95% CI -2.89-0.51; p = 0.17), and hospital LOS (WMD = -0.31; 95% CI -0.76-0.15; p = 0.19).

CONCLUSIONS

Perioperative DEX reduced the incidence of postoperative AKI in adult patients undergoing cardiac surgery. No significant decrease existed in mortality, MV duration, ICU LOS and hospital LOS owing to DEX administration.

Effect of opioid-free anesthesia on post-operative period in cytoreductive surgery with hyperthermic intraperitoneal chemotherapy: a propensity score matched study

BACKGROUND

Postoperative pain after cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is important. It appears essential to reduce postoperative pain and morphine consumption.

METHODS

Retrospective study in a university hospital comparing patient benefiting from CRS-HIPEC under opioid-free anesthesia (OFA; dexmedetomidine) to those anesthetized with opioid anesthesia (OA; remifentanil) using a propensity score matching method. The main objective was the impact of OFA on postoperative morphine consumption in the first 24 h after surgery.

RESULTS

102 patients were included, matching on the propensity score allowed selecting 34 unique pairs analyzed. Morphine consumption was lower in the OFA group than in the OA group (3.0 [0.00-11.0] mg/24 h vs. 13.0 [2.5-25.0] mg/24 h; p = 0.02). In multivariable analysis, OFA was associated with a reduction of 7.2 [0.5-13.9] mg of postoperative morphine (p = 0.04). The rate of renal failure with a KDIGO-score > 1 was lower in the OFA group than in the OA group (12% vs. 38%; p = 0.01). There was no difference between groups concerning length of surgery/anesthesia, norepinephrine infusion, volume of fluid therapy, post-operative complications, rehospitalization or ICU readmission within 90 days, mortality, and postoperative rehabilitation.

CONCLUSION

Our results suggest that OFA for CRS-HIPEC patients appears safe and is associated with less postoperative morphine use and acute kidney injury.

Treatment strategies and drug resistance mechanisms in adenocarcinoma of different organs

Adenocarcinoma is a common type of malignant tumor, originating from glandular epithelial cells in various organs, such as pancreas, breast, lung, stomach, colon, rectus, and prostate. For patients who lose the opportunity for radical surgery, medication is available to provide potential clinical benefits. However, drug resistance is a big obstacle to obtain desired clinical prognosis. In this review, we provide a summary of treatment strategies and drug resistance mechanisms in adenocarcinoma of different organs, including pancreatic cancer, gastric adenocarcinoma, colorectal adenocarcinoma, lung adenocarcinoma, and prostate cancer. Although the underlying molecular mechanisms involved in drug resistance of adenocarcinoma vary from one organ to the other, there are several targets that are universal for drug resistance in adenocarcinoma, and targeting these molecules could potentially reverse drug resistance in the treatment of adenocarcinomas.

Acute Kidney Injury and Renal Replacement Therapy: A Review and Update for the Perioperative Physician

Post-operative acute kidney injury is a devastating complication with significant morbidity and mortality associated with it. The perioperative anesthesiologist is in a unique position to potentially mitigate the risk of postoperative AKI, however, understanding the pathophysiology, risk factors and preventative strategies is paramount. There are also certain clinical scenarios, where renal replacement therapy may be indicated intraoperatively including severe electrolyte abnormalities, metabolic acidosis and massive volume overload. A multidisciplinary approach including the nephrologist, critical care physician, surgeon and anesthesiologist is necessary to determine the optimal management of these critically ill patients.

Cardiac surgery-associated acute kidney injury in newborns: A meta-analysis

<b>Introduction</b>: Acute kidney injury is a common complication following pediatric heart surgery, and it has been linked to an increased risk of morbidity and fatality.<br /> <b>Methods</b>: The PubMed and Medline databases were combed for relevant research until May 2022. The terms [Cardiac surgery] AND [acute renal injury] AND [newborns OR children OR neonates] AND [randomized control studies OR randomized control trials] were used as search criteria. The studies that met the inclusion criteria were considered qualified using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines.<br /> <b>Results</b>: A total of 2,941 newborns or children were enrolled in 14 studies, with 931 developing acute renal damage. 2,095 of the enrolled infants and children received steroid, aminophylline, dexmedetomidine, and acetaminophen therapies. In seven studies, the odds ratio for steroids was not significantly different from control. In contrast, two studies comparing aminophylline to a control group found no statistically significant change. Two studies found no significant difference in dexmedetomidine therapy compared to control. Three trials, however, found a significant difference between the acetaminophen treatment and control groups.<br /> <b>Conclusion</b>: Acetaminophen was linked to a decreased risk of postoperative acute renal injury, while steroids had no benefit and aminophylline treatment could be justified.

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.

Perioperative dexmedetomidine administration does not reduce the risk of acute kidney injury after non-cardiac surgery: a meta-analysis

BACKGROUND

Post-operative acute kidney injury (AKI) is one of the most common and serious complications after major surgery and is significantly associated with increased risks of morbidity and mortality. This meta-analysis was conducted to evaluate the effects of perioperative dexmedetomidine (Dex) administration on the occurrence of AKI and the outcomes of recovery after non-cardiac surgery.

METHODS

The PubMed, Embase, Web of Science, and Cochrane Library databases were systematically searched for studies comparing the effects of Dex vs. placebo on kidney function after non-cardiac surgery, and a pooled fixed-effect meta-analysis of the included studies was performed. The primary outcome was the occurence of post-operative AKI. The secondary outcomes included the occurence of intra-operative hypotension and bradycardia, intensive care unit (ICU) admission, duration of ICU stay, and hospital length of stay (LOS).

RESULTS

Six studies, including four randomized controlled trials (RCTs) and two observational studies, with a total of 2586 patients were selected. Compared with placebo, Dex administration could not reduce the odds of post-operative AKI (odds ratio [OR], 0.44; 95% confidence interval (CI), 0.18-1.06; P  = 0.07; I2  = 0.00%, P  = 0.72) in RCTs, but it showed a significant renoprotective effect (OR, 0.67; 95% CI, 0.48-0.95; P  = 0.02; I2  = 0.00%, P  = 0.36) in observational studies. Besides, Dex administration significantly increased the odds of intra-operative bradycardia and shortened the duration of ICU stay. However, there was no significant difference in the odds of intra-operative hypotension, ICU admission, and hospital LOS.

CONCLUSIONS

This meta-analysis suggests that perioperative Dex administration does not reduce the risk of AKI after non-cardiac surgery. However, the quality of evidence for this result is low due to imprecision and inconsistent types of non-cardiac operations. Thus, large and high-quality RCTs are needed to verify the real effects of perioperative Dex administration on the occurrence of AKI and the outcomes of recovery after non-cardiac surgery.

Perioperative Management of the Patient at High-Risk for Cardiac Surgery-Associated Acute Kidney Injury

Acute kidney injury (AKI) is one of the most common major complications of cardiac surgery, and is associated with increased morbidity and mortality. Cardiac surgery-associated AKI has a complex, multifactorial etiology, including numerous factors such as primary cardiac dysfunction, hemodynamic derangements of cardiac surgery and cardiopulmonary bypass, and the possibility of a large volume of blood transfusion. There are no truly effective pharmacologic therapies for the management of AKI, and, therefore, anesthesiologists, intensivists, and cardiac surgeons must remain vigilant and attempt to minimize the risk of developing renal dysfunction. This narrative review describes the current state of the scientific literature concerning the specific aspects of cardiac surgery-associated AKI, and presents it in a chronological fashion to aid the perioperative clinician in their approach to this high-risk patient group. The evidence was considered for risk prediction models, preoperative optimization, and the intraoperative and postoperative management of cardiac surgery patients to improve renal outcomes.

Effect of dexmedetomidine for prevention of acute kidney injury after cardiac surgery: an updated systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is a serious complication related to cardiac surgery. Several studies have been conducted to investigate the effect of dexmedetomidine administration on AKI prevention.

OBJECTIVE

To assess if dexmedetomidine is associated with a protective effect of renal function after cardiac surgery. And the aim of conducting this meta-analysis is to summarize the literature and determine the clinical utility of dexmedetomidine administration in patients undergoing cardiac surgery.

METHODS

PubMed, Cochrane Library, and EMBASE databases were comprehensively searched for all randomized controlled trials (RCTs) published before 1 December, 2021 that investigated the effect of dexmedetomidine on AKI prevention.

RESULTS

Our analysis included 16 studies involving 2148 patients. Compared with the control group, dexmedetomidine administration significantly reduced AKI incidence (OR, 0.47; 95% CI, 0.36-0.61; p <  0.00001; I2 = 26%) and the length of stay in the intensive care unit (ICU) but did not alter mortality rate, length of stay in the hospital, and mechanical ventilation time. Furthermore, the incidence of delirium among patients treated with dexmedetomidine was significantly decreased.

CONCLUSION

Dexmedetomidine administration has a positive effect on preventing AKI and postoperative delirium after cardiac surgery and significantly reduces the length of stay in the ICU.

Effects of dexmedetomidine on hemodynamic, oxygenation, microcirculation, and inflammatory markers in a porcine model of sepsis

PURPOSE

To determine whether dexmedetomidine aggravates hemodynamic, metabolic variables, inflammatory markers, and microcirculation in experimental septic shock.

METHODS

Twenty-four pigs randomized into: Sham group (n = 8), received saline; Shock group (n = 8), received an intravenous infusion of Escherichia coli O55 (3 × 109 cells/mL, 0.75 mL/kg, 1 hour); Dex-Shock group (n = 8), received bacteria and intravenous dexmedetomidine (bolus 0.5 mcg/kg followed by 0.7 mcg/kg/h). Fluid therapy and/ornorepinephrine were administered to maintain a mean arterial pressure > 65 mmHg. Hemodynamic, metabolic, oxygenation, inflammatory markers, and microcirculation were assessed at baseline, at the end of bacterial infusion, and after 60, 120, 180, and 240 minutes.

RESULTS

Compared to Shock group, Dex-Shock group presented a significantly increased oxygen extraction ratio at T180 (23.1 ± 9.7 vs. 32.5 ± 9.2%, P = 0.0220), decreased central venous pressure at T120 (11.6 ± 1 vs. 9.61 ± 1.2 mmHg, P = 0.0214), mixed-venous oxygen saturation at T180 (72.9 ± 9.6 vs. 63.5 ± 9.2%, P = 0.026), and increased plasma lactate (3.7 ± 0.5 vs. 5.5 ± 1 mmol/L, P = 0.003). Despite the Dex-Shock group having a better sublingual vessel density at T240 (12.5 ± 0.4 vs. 14.4 ± 0.3 mL/m2; P = 0.0003), sublingual blood flow was not different from that in the Shock group (2.4 ± 0.2 vs. 2.4 ± 0.1 mL/kg, P = 0.4418).

CONCLUSIONS

Dexmedetomidine did not worsen the hemodynamic, metabolic, inflammatory, or sublingual blood flow disorders resulting from septic shock. Despite inducing a better sublingual vessel density, dexmedetomidine initially and transitorily increased the mismatch between oxygen supply and demand.

Acute kidney injury-associated delirium: a review of clinical and pathophysiological mechanisms

Acute kidney injury is a known clinical risk factor for delirium, an acute cognitive dysfunction that is commonly encountered in the critically ill population. In this comprehensive review of clinical and basic research studies, we detail the epidemiology, clinical implications, pathogenesis, and management strategies of patients with acute kidney injury-associated delirium. Specifically addressed are the pathological roles of endogenous toxin or drug accumulation, acute kidney injury-mediated neuroinflammation, and acute kidney injury-associated volume overload as discrete potential biological mechanisms of the condition. The optimization of clinical contributors and normalization of renal function are reviewed as pragmatic management strategies in addition to potential and emerging therapeutic approaches.

Effects of Dexmedetomidine Administered Through Different Routes on Kidney Tissue in Rats with Spinal Cord Ischaemia-Reperfusion Injury

BACKGROUND

Ischaemia-reperfusion (IR) injury, which can be encountered during surgical procedures involving the abdominal aorta, is a complex process that affects distant organs, such as the heart, liver, kidney, and lungs, as well as the lower extremities. In this study, we aimed to contribute to the limited literature by investigating the protective effect of dexmedetomidine, which was administered through different routes, on kidney tissue in rats with spinal cord IR injury.

METHODS

A total of 30 rats were randomly divided into five groups: control (C group), IR (IR group), IR-intraperitoneal dexmedetomidine (IRIPD group), IR-intrathecal dexmedetomidine (IRITD group), and IR-intravenous dexmedetomidine (IRIVD group). The spinal cord IR model was established. Dexmedetomidine was administered at doses of 100 µg/kg intraperitoneally, 3 µg/kg intrathecally, and 9 µg/kg intravenously. Histopathologic parameters in kidney tissue samples taken at the end of the reperfusion period and biochemical parameters in serum were evaluated.

RESULTS

When examined histopathologically, tubular dilatation was found to be significantly reduced in the IRIVD, IRITD, and IRIPD groups compared with the IR group (p = 0.012, all). Vascular vacuolization and hypertrophy were significantly decreased in the IRIVD, IRITD, and IRIPD groups compared with the IR group (p = 0.006, all). Tubular cell degeneration and necrosis were significantly reduced in the IRIVD, IRITD, and IRIPD groups compared with the IR group (p = 0.008, p = 0.08, and p = 0.030, respectively). Lymphocyte infiltration was significantly decreased in the IRIVD and IRITD groups compared with the IR group (p = 0.006 and p = 0.06, respectively).

CONCLUSION

It was observed that dexmedetomidine administered by different routes improved the damage caused by IR in kidney histopathology. We think that the renoprotective effects of dexmedetomidine administered intravenously and intrathecally before IR in rats are greater.

Society of Cardiovascular Anesthesiologists Clinical Practice Update for Management of Acute Kidney Injury Associated With Cardiac Surgery

Cardiac surgery-associated acute kidney injury (CS-AKI) is common and is associated with increased risk for postoperative morbidity and mortality. Our recent survey of the Society of Cardiovascular Anesthesiologists (SCA) membership showed 6 potentially renoprotective strategies for which clinicians would most value an evidence-based review (ie, intraoperative target blood pressure, choice of specific vasopressor agent, erythrocyte transfusion threshold, use of alpha-2 agonists, goal-directed oxygen delivery on cardiopulmonary bypass [CPB], and the "Kidney Disease Improving Global Outcomes [KDIGO] bundle of care"). Thus, the SCA's Continuing Practice Improvement Acute Kidney Injury Working Group aimed to provide a practice update for each of these strategies in cardiac surgical patients based on the evidence from randomized controlled trials (RCTs). PubMed, EMBASE, and Cochrane library databases were comprehensively searched for eligible studies from inception through February 2021, with search results updated in August 2021. A total of 15 RCTs investigating the effects of the above-mentioned strategies on CS-AKI were included for meta-analysis. For each strategy, the level of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. Across the 6 potentially renoprotective strategies evaluated, current evidence for their use was rated as "moderate," "low," or "very low." Based on eligible RCTs, our analysis suggested using goal-directed oxygen delivery on CPB and the "KDIGO bundle of care" in high-risk patients to prevent CS-AKI (moderate level of GRADE evidence). Our results suggested considering the use of vasopressin in vasoplegic shock patients to reduce CS-AKI (low level of GRADE evidence). The decision to use a restrictive versus liberal strategy for perioperative red cell transfusion should not be based on concerns for renal protection (a moderate level of GRADE evidence). In addition, targeting a higher mean arterial pressure during CPB, perioperative use of dopamine, and use of dexmedetomidine did not reduce CS-AKI (a low or very low level of GRADE evidence). This review will help clinicians provide evidence-based care, targeting improved renal outcomes in adult patients undergoing cardiac surgery.

Controversies in enhanced recovery after cardiac surgery

Advances in cardiac surgical operative techniques and myocardial protection have dramatically improved outcomes in the past two decades. An unfortunate and unintended consequence is that 80% of the preventable morbidity and mortality following cardiac surgery now originates outside of the operating room. Our hope is that a renewed emphasis on evidence-based best practice and standardized perioperative care will reduce overall morbidity and mortality and improve patient-centric care. The Perioperative Quality Initiative (POQI) and Enhanced Recovery After Surgery–Cardiac Society (ERAS® Cardiac) have identified significant evidence gaps in perioperative medicine related to cardiac surgery, defined as areas in which there is significant controversy about how best to manage patients. These five areas of focus include patient blood management, goal-directed therapy, acute kidney injury, opioid analgesic reduction, and delirium.

Renal and Cerebral Hypoxia and Inflammation During Cardiopulmonary Bypass

Cardiac surgery-associated acute kidney injury and brain injury remain common despite ongoing efforts to improve both the equipment and procedures deployed during cardiopulmonary bypass (CPB). The pathophysiology of injury of the kidney and brain during CPB is not completely understood. Nevertheless, renal (particularly in the medulla) and cerebral hypoxia and inflammation likely play critical roles. Multiple practical factors, including depth and mode of anesthesia, hemodilution, pump flow, and arterial pressure can influence oxygenation of the brain and kidney during CPB. Critically, these factors may have differential effects on these two vital organs. Systemic inflammatory pathways are activated during CPB through activation of the complement system, coagulation pathways, leukocytes, and the release of inflammatory cytokines. Local inflammation in the brain and kidney may be aggravated by ischemia (and thus hypoxia) and reperfusion (and thus oxidative stress) and activation of resident and infiltrating inflammatory cells. Various strategies, including manipulating perfusion conditions and administration of pharmacotherapies, could potentially be deployed to avoid or attenuate hypoxia and inflammation during CPB. Regarding manipulating perfusion conditions, based on experimental and clinical data, increasing standard pump flow and arterial pressure during CPB appears to offer the best hope to avoid hypoxia and injury, at least in the kidney. Pharmacological approaches, including use of anti-inflammatory agents such as dexmedetomidine and erythropoietin, have shown promise in preclinical models but have not been adequately tested in human trials. However, evidence for beneficial effects of corticosteroids on renal and neurological outcomes is lacking. © 2021 American Physiological Society. Compr Physiol 11:1-36, 2021.

Frequency of Renal Dysfunction and its effects on outcomes after open heart surgery

Objectives:

In this study we determined the frequency of renal dysfunction and its outcomes in terms of morbidity and mortality in patients who underwent open heart surgery at the Aga Khan University Hospital, Karachi, Pakistan.

Methods:

A total of 175 patients aged between 15-80 years having open heart Surgery(OHS) were included. Preoperative and postoperative serum creatinine (SCr) was noted and the glomerular filtration rate (GFR) calculated by Cockcroft-Gault equation. Their hospital course was charted and followed-up for 30-day.

Results:

The mean age and mean BMI were 58.1±12.6 years and 26.4±4.3 kg/m2 respectively. Females were 18.3%, out of which 51.4% hypertensive, 46.9% diabetics, 45.1% had dyslipidemia, 2.9% had preoperative renal dysfunction and 40% had moderate ejection fraction. On follow up, 30.3% developed postoperative renal dysfunction within 30-days after OHS with mean SCr and GFR as 1.6±0.7 and 56.9±24.5, respectively. In RD group more patients showed positive outcomes i.e. prolonged inotropic requirement (75.5% vs. 18%, p-value <0.005), diuretic infusion usage (47.2% vs. 3.3%, p-value <0.005), dialysis/renal replacement therapy (17% vs. 0%, p-value <0.005), requirement for prolonged ventilation (35.8% vs. 6.6%, p-value <0.005), prolonged ICU and hospital stay (15.4% vs. 1.6%, p-value <0.005 and 41.5% vs. 17.2%, p-value <0.005), sepsis (20.8% vs. 1.6%, p-value <0.005) and death (9.4% vs. 2.5%, p-value 0.05).

Conclusion:

Timely recognition of renal dysfunction, early renal replacement therapy, diuretics or dialysis and proper nutritional and inotropic support to maintain adequate hemostasis shows survival benefits.

CSA-AKI: Incidence, Epidemiology, Clinical Outcomes, and Economic Impact

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common complication following cardiac surgery and reflects a complex biological combination of patient pathology, perioperative stress, and medical management. Current diagnostic criteria, though increasingly standardized, are predicated on loss of renal function (as measured by functional biomarkers of the kidney). The addition of new diagnostic injury biomarkers to clinical practice has shown promise in identifying patients at risk of renal injury earlier in their course. The accurate and timely identification of a high-risk population may allow for bundled interventions to prevent the development of CSA-AKI, but further validation of these interventions is necessary. Once the diagnosis of CSA-AKI is established, evidence-based treatment is limited to supportive care. The cost of CSA-AKI is difficult to accurately estimate, given the diverse ways in which it impacts patient outcomes, from ICU length of stay to post-hospital rehabilitation to progression to CKD and ESRD. However, with the global rise in cardiac surgery volume, these costs are large and growing.

Cardiac Surgery Associated AKI Prevention Strategies and Medical Treatment for CSA-AKI

Acute kidney injury (AKI) is common after cardiac surgery. To date, there are no specific pharmacological therapies. In this review, we summarise the existing evidence for prevention and management of cardiac surgery-associated AKI and outline areas for future research. Preoperatively, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers should be withheld and nephrotoxins should be avoided to reduce the risk. Intraoperative strategies include goal-directed therapy with individualised blood pressure management and administration of balanced fluids, the use of circuits with biocompatible coatings, application of minimally invasive extracorporeal circulation, and lung protective ventilation. Postoperative management should be in accordance with current KDIGO AKI recommendations.

The Protective Effect of Dexmedetomidine Against Ischemia-Reperfusion Injury after Hepatectomy: A Meta-Analysis of Randomized Controlled Trials

Background: Hepatic inflow occlusion proceeded to reduce blood loss during hepatectomy induces ischemia-reperfusion (IR) injury in the remnant liver. Dexmedetomidine, a selective α₂-adrenoceptor agonist used as an anesthetic adjuvant, has been shown to attenuate IR injury in preclinical and clinical studies. However, a meta-analysis is needed to systematically evaluate the protective effect of perioperative dexmedetomidine use on IR injury induced by hepatectomy.

Methods: A prospectively registered meta-analysis following Cochrane and PRISMA guidelines concerning perioperative dexmedetomidine use on IR injury after hepatectomy was performed via searching Cochrane Library, PubMed, EMBASE, ClinicalTrials.gov, Web of Science, CNKI, WanFang, and Sinomed for eligible randomized controlled trials up to 2021.3.31. The main outcome is postoperative liver function. Risk of bias was assessed by the Cochrane Risk of Bias tool. Review Manager 5.3 and Stata12.0 were applied to perform data analyses.

Results: Eight RCTs enrolling 468 participants were included. Compared with 0.9% sodium chloride, dexmedetomidine decreased serum concentration of ALT (WMD = −66.54, 95% CI: −92.10–−40.98), AST (WMD= −82.96, 95% CI: −106.74–−59.17), TBIL (WMD = −4.51, 95% CI: −7.32–−1.71), MDA (WMD = −3.09, 95% CI: −5.17–−1.01), TNF-α (WMD = −36.54, 95% CI: −61.33–−11.95) and IL-6 (WMD = −165.05, 95% CI: −225.76–−104.34), increased SOD activity (WMD = 24.70, 95% CI: 18.09–31.30) within postoperative one day. There was no significant difference in intraoperative or postoperative recovery parameters between groups.

Conclusions: Perioperative administration of dexmedetomidine can exert a protective effect on liver IR injury after hepatectomy. Additional studies are needed to further evaluate postoperative recovery outcomes of dexmedetomidine with different dosing regimens.

Is the Sympathetic System Detrimental in the Setting of Septic Shock, with Antihypertensive Agents as a Counterintuitive Approach? A Clinical Proposition

Mortality in the setting of septic shock varies between 20% and 100%. Refractory septic shock leads to early circulatory failure and carries the worst prognosis. The pathophysiology is poorly understood despite studies of the microcirculatory defects and the immuno-paralysis. The acute circulatory distress is treated with volume expansion, administration of vasopressors (usually noradrenaline: NA), and inotropes. Ventilation and anti-infectious strategy shall not be discussed here. When circulation is considered, the literature is segregated between interventions directed to the systemic circulation vs. interventions directed to the micro-circulation. Our thesis is that, after stabilization of the acute cardioventilatory distress, the prolonged sympathetic hyperactivity is detrimental in the setting of septic shock. Our hypothesis is that the sympathetic hyperactivity observed in septic shock being normalized towards baseline activity will improve the microcirculation by recoupling the capillaries and the systemic circulation. Therefore, counterintuitively, antihypertensive agents such as beta-blockers or alpha-2 adrenergic agonists (clonidine, dexmedetomidine) are useful. They would reduce the noradrenaline requirements. Adjuncts (vitamins, steroids, NO donors/inhibitors, etc.) proposed to normalize the sepsis-evoked vasodilation are not reviewed. This itemized approach (systemic vs. microcirculation) requires physiological and epidemiological studies to look for reduced mortality.

Dexmedetomidine reduces acute kidney injury after endovascular aortic repair of Stanford type B aortic dissection: A randomized, double-blind, placebo-controlled pilot study

STUDY OBJECTIVE

To determine the effect of dexmedetomidine on acute kidney injury (AKI) following endovascular aortic repair (EVAR) for Stanford type B aortic dissection (TBAD).

DESIGN

Randomized, double-blind, placebo-controlled, pilot study.

SETTING

University Hospital.

PATIENTS

102 TBAD patients undergoing EVAR procedures were enrolled. Patients with dissection involving aortic arch or renal artery were excluded.

INTERVENTIONS

Patients were randomly assigned, in a 1:1 ratio, to a dexmedetomidine group (intravenous dexmedetomidine 0.4 μg/kg/h immediately after anesthesia induction and 0.1 μg/kg/h after extubation, which was maintained until 24 h) or a normal saline control group.

MEASUREMENTS

The primary outcome was the incidence of AKI within the first two days after surgery, based on the Acute Kidney Injury Network (AKIN) criteria. The secondary outcomes included serum cystatin C and estimated glomerular filtration rate on postoperative days 1, 2, and 7, and in-hospital need for renal replacement therapy (RRT). Long-term outcomes included RRT and all-cause mortality.

MAIN RESULTS

Ninety-eight patients completed the study (dexmedetomidine, n = 48; control, n = 50). AKIN stage 1 AKI occurred in 3/48 (6.3%) patients receiving dexmedetomidine, compared with 11/50 (22%) patients receiving normal saline (odds ratio = 0.24, 95% CI: 0.07 to 0.89, P = 0.041). This difference remained significant after adjusting for baseline covariates (adjusted odds ratio = 0.21, 95% CI: 0.05 to 0.84; P = 0.028). Dexmedetomidine led to a lower serum cystatin C on postoperative day 1 (median [IQR] mg/L: 1.31 [1.02-1.72] vs. 1.58 [1.28-1.96]). There were no between-group differences in other secondary or long-term outcomes. During the follow-up (median = 28.4 months), 1 patient in the dexmedetomidine group and 3 patients in the control group required RRT.

CONCLUSIONS

Dexmedetomidine reduced the incidence of AKI in TBAD patients after EVAR procedures. The long-term benefits of dexmedetomidine in this patient population warrant further investigation.

TRIAL REGISTRATION

ChiCTR-IPR-15006372.

The Role of Dexmedetomidine for the Prevention of Acute Kidney Injury in Critical Care

Acute kidney injury (AKI) occurs in up to 50% of patients admitted to the intensive care unit and is associated with increased mortality. Currently, there is no effective pharmacotherapy for prevention or treatment of AKI. In animal models of sepsis and ischaemia-reperfusion, α2-agonists like dexmedetomidine (DEX) exhibit anti-inflammatory properties and experimental data indicate a potential protective effect of DEX on renal function. However, clinical trials have yielded inconsistent results in critically ill patients. This review discusses the pathophysiological mechanisms involved in AKI, the renal effects of DEX in various intensive care unit-related conditions, and summarises the available literature addressing the use of DEX for the prevention of AKI.

Dexmedetomidine, Delirium, and Adverse Outcomes: Analysis of the STS Adult Cardiac Surgery Database

BACKGROUND

We tested the hypothesis that dexmedetomidine was associated with a reduced incidence of postoperative delirium (POD) and adverse outcomes in cardiac surgery patients from the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (ACSD) including the Adult Cardiac Anesthesiology subsection.

METHODS

We identified 55905 patients in the STS ACSD who underwent cardiac surgery between July 2014 and December 2018. Using propensity score weighted regression analysis, we analyzed the effect of intraoperative dexmedetomidine (intraDex) on the primary (POD) and secondary outcomes (highest pain score on day 3 and at discharge, stroke, prolonged ventilation, postoperative intubation/reintubation, additional postoperative hours ventilated, renal failure, atrial fibrillation, and 30-day mortality). In separate propensity score weighted analyses, we examined the effect of postoperative dexmedetomidine (postopDex) on the highest postoperative pain score at discharge and 30-day mortality.

RESULTS

The rate of intraDex use was 25.5% (n=13963), and its administration was associated with increased odds for POD (odds ratio [OR], 1.85; 95% CI, 1.60-2.13), a small higher average pain score on day 3 (difference in mean [MD], 0.08; 95% CI, 0.02 to 0.14), increased odds for postoperative intubation/reintubation (OR, 1.29; 95% CI, 1.12-1.48), and a small lower average pain score at discharge (MD, -0.31; 95% CI, -0.21 to -0.41). PostDex was associated with a small higher average pain score at discharge (MD, 0.27, 95% CI, 0.21 to 0.34), and higher odds for 30-day mortality (OR, 1.25, 95% CI, 1.07-1.46).

CONCLUSIONS

In this registry of cardiac surgical patients dexmedetomidine administration was associated with POD and adverse outcomes.

New drugs for acute kidney injury

PURPOSE OF REVIEW

To describe recent advances in the development of therapeutic agents for acute kidney injury (AKI).

RECENT FINDINGS

Traditional care for AKI is mostly supportive. At present, no specific therapy has been developed to prevent or treat AKI. However, based on a better understanding of the pathophysiology of AKI, various potential compounds have been recently identified and tested. A variety of pathways has been targeted, including oxidative and mitochondrial stress, cellular metabolism and repair, inflammation, apoptosis and hemodynamics. Many of these potential agents are currently ongoing early-phase clinical trials, and the purpose of this review is to provide a summary of those with the most potential.

SUMMARY

Despite the lack of therapies specifically approved for AKI, many interesting potential agents are entering clinical trials, with the potential to transform the care of patients with AKI.

Perioperative Renoprotection: General Mechanisms and Treatment Approaches

In the perioperative setting, acute kidney injury (AKI) is a frequent complication, and AKI itself is associated with adverse outcomes such as higher risk of chronic kidney disease and mortality. Various risk factors are associated with perioperative AKI, and identifying them is crucial to early interventions addressing modifiable risk and increasing monitoring for nonmodifiable risk. Different mechanisms are involved in the development of postoperative AKI, frequently picturing a multifactorial etiology. For these reasons, no single renoprotective strategy will be effective for all surgical patients, and efforts have been attempted to prevent kidney injury in different ways. Some renoprotective strategies and treatments have proven to be useful, some are no longer recommended because they are ineffective or even harmful, and some strategies are still under investigation to identify the best timing, setting, and patients for whom they could be beneficial. With this review, we aim to provide an overview of recent findings from studies examining epidemiology, risk factors, and mechanisms of perioperative AKI, as well as different renoprotective strategies and treatments presented in the literature.

Management of Acute Kidney Injury Following Major Abdominal Surgery: A Contemporary Review

Acute kidney injury (AKI) is a frequent occurrence following major abdominal surgery and is independently associated with both in-hospital and long-term mortality, as well as with a higher risk of progressing to chronic kidney disease (CKD) and cardiovascular events. Postoperative AKI can account for up to 40% of in-hospital AKI cases. Given the differences in patient characteristics and the pathophysiology of postoperative AKI, it is inappropriate to assume that the management after noncardiac and nonvascular surgery are the same as those after cardiac and vascular surgery. This article provides a comprehensive review on the available evidence on the management of postoperative AKI in the setting of major abdominal surgery.

Dexmedetomidine in the prevention of postoperative delirium in elderly patients following non-cardiac surgery: A systematic review and meta-analysis

The efficacy of dexmedetomidine in the prevention of postoperative delirium (POD) remains ambiguous, however, it has been used to reduce the incidence of delirium in elderly patients. Here, we conducted a meta-analysis study for assessing the effects of dexmedetomidine on POD among elderly patients following non-cardiac surgery. A systematic literature search was performed against the PubMed, EMBASE, Cochrane Library, and Web of Science databases, and all relevant literature published till November 30, 2019, were considered. Our analysis included 16 randomised controlled trials conducted with 4534 patients for exploring the effects of dexmedetomidine on POD in elderly patients following non-cardiac surgery. It was observed that the overall incidence of POD was significantly lower in the dexmedetomidine group than in the control group (risk ratio [RR] 0.51, 95% confidence interval [CI] 0.43-0.61, P < .01). Similar results were obtained from subgroup analysis upon comparison of the placebo (RR 0.52, 95% CI 0.41-0.66, P < .01, moderate quality of evidence), propofol-treated (RR 0.55, 95% CI 0.38-0.78, P < .01, low quality of evidence), and midazolam-treated (RR 0.38, 95% CI 0.20-0.71, P < .01, low quality of evidence) groups. Trial sequential analysis revealed that the cumulative z-value superseded the monitoring boundary and reached the required information size. However, patients who received dexmedetomidine had a higher incidence of bradycardia and hypotension. In conclusion, the meta-analysis revealed that dexmedetomidine appears to decrease the risk of POD in elderly patients following non-cardiac surgery. However, as some of the studies were heterogeneous and of low quality, high-quality trials are necessary for drawing more definitive conclusions.

Dexmedetomidine for reduction of atrial fibrillation and delirium after cardiac surgery (DECADE): a randomised placebo-controlled trial

BACKGROUND

Atrial fibrillation and delirium are common consequences of cardiac surgery. Dexmedetomidine has unique properties as sedative agent and might reduce the risk of each complication. This study coprimarily aimed to establish whether dexmedetomidine reduces the incidence of new-onset atrial fibrillation and the incidence of delirium.

METHODS

A randomised, placebo-controlled trial was done at six academic hospitals in the USA. Patients who had had cardiac surgery with cardiopulmonary bypass were enrolled. Patients were randomly assigned 1:1, stratified by site, to dexmedetomidine or normal saline placebo. Randomisation was computer generated with random permuted block size 2 and 4, and allocation was concealed by a web-based system. Patients, caregivers, and evaluators were all masked to treatment. The study drug was prepared by the pharmacy or an otherwise uninvolved research associate so that investigators and clinicians were fully masked to allocation. Participants were given either dexmedetomidine infusion or saline placebo started before the surgical incision at a rate of 0·1 μg/kg per h then increased to 0·2 μg/kg per h at the end of bypass, and postoperatively increased to 0·4 μg/kg per h, which was maintained until 24 h. The coprimary outcomes were atrial fibrillation and delirium occurring between intensive care unit admission and the earlier of postoperative day 5 or hospital discharge. All analyses were intention-to-treat. The trial is registered with ClinicalTrials.gov, NCT02004613 and is closed.

FINDINGS

798 patients of 3357 screened were enrolled from April 17, 2013, to Dec 6, 2018. The trial was stopped per protocol after the last designated interim analysis. Among 798 patients randomly assigned, 794 were analysed, with 400 assigned to dexmedetomidine and 398 assigned to placebo. The incidence of atrial fibrillation was 121 (30%) in 397 patients given dexmedetomidine and 134 (34%) in 395 patients given placebo, a difference that was not significant: relative risk 0·90 (97·8% CI 0·72, 1·15; p=0·34). The incidence of delirium was non-significantly increased from 12% in patients given placebo to 17% in those given dexmedetomidine: 1·48 (97·8% CI 0·99-2·23). Safety outcomes were clinically important bradycardia (requiring treatment) and hypotension, myocardial infarction, stroke, surgical site infection, pulmonary embolism, deep venous thrombosis, and death. 21 (5%) of 394 patients given dexmedetomidine and 8 (2%) of 396 patients given placebo, had a serious adverse event as determined by clinicians. 1 (<1%) of 391 patients given dexmedetomidine and 1 (<1%) of 387 patients given placebo died.

INTERPRETATION

Dexmedetomidine infusion, initiated at anaesthetic induction and continued for 24 h, did not decrease postoperative atrial arrhythmias or delirium in patients recovering from cardiac surgery. Dexmedetomidine should not be infused to reduce atrial fibrillation or delirium in patients having cardiac surgery.

FUNDING

Hospira Pharmaceuticals.

Dexmedetomidine pretreatment attenuates myocardial ischemia reperfusion induced acute kidney injury and endoplasmic reticulum stress in human and rat

BACKGROUND

Patients undergoing cardiopulmonary bypass (CPB) often develop acute kidney injury (AKI) caused by myocardial ischemia reperfusion (MI/R), and this renal injury can be resolved notably by dexmedetomidine. Endoplasmic reticulum (ER) stress was reported to get involved in organ injury including AKI.

OBJECTIVES

The current study aimed to address the correlation between MI/R induced AKI with ER stress and to assess the effects of dexmedetomidine pretreatment on AKI protection.

METHOD

Patients selected for heart valve replacement surgery were randomly assigned to NS group (pre-anesthesia with 0.9% NaCl) and DEX group (pre-anesthesia with dexmedetomidine). Rat MI/R model was induced by occluding coronary artery for 30 min followed by 48-hour reperfusion. Rats were randomized into Sham (0.9% NaCl), I/R (MI/R + 0.9% NaCl) and I/R + DEX (MI/R + dexmedetomidine). Organ function and ER stress condition were evaluated by blood chemistry, pathology, and molecular test.

RESULTS

Clinical data indicated dexmedetomidine pretreatment attenuated AKI and oxidative stress as well as postischemic myocardial injury in patients. Accordingly animal results suggested dexmedetomidine reduced cellular injury and improved postischemic myocardial and renal function. Dexmedetomidine also reduced myocardial and renal cells apoptosis and down-regulated ER stress.

CONCLUSIONS

These results suggested that dexmedetomidine pretreatment attenuates MI/R injury-induced AKI by relieving the ER stress.

Perioperative Dexmedetomidine Improves Outcomes of Kidney Transplant

Graft function is crucial for successful kidney transplantation. Many factors may affect graft function or cause delayed graft function (DGF), which decreases the prognosis for graft survival. This study was designed to evaluate whether the perioperative use of dexmedetomidine (Dex) could improve the incidence of function of graft kidney and complications after kidney transplantation. A total of 780 patients underwent kidney transplantations, 315 received intravenous Dex infusion during surgery, and 465 did not. Data were adjusted with propensity scores and multivariate logistic regression was used. The primary outcomes are major adverse complications, including DGF and acute rejection in the early post‐transplantation phase. The secondary outcomes included length of hospital stay (LOS), infection, overall complication, graft functional status, post‐transplantation serum creatinine values, and estimated glomerular filtration rate (eGFR). Dex use significantly decreased DGF (19.37% vs. 23.66%; adjusted odds ratio, 0.744; 95% confidence interval, 0.564–0.981; P = 0.036), risk of infection, risk of acute rejection in the early post‐transplantation phase, the risk of overall complications, and LOS. However, there were no statistical differences in 90‐day graft functional status or 7‐day, 30‐day, and 90‐day eGFR. Perioperative Dex use reduced incidence of DGF, risk of infection, risk of acute rejection, overall complications, and LOS in patients who underwent kidney transplantation.

Perioperative acute kidney injury: Stratification and risk reduction strategies

Perioperative acute kidney injury (AKI) is associated with increased morbidity and mortality. Patient comorbidities, the type of surgery, timing of surgery, and exposure to nephrotoxins are important contributors for developing acute kidney injury. Urgent or emergent surgery, cardiac, and organ transplantation procedures are associated with a higher risk of acute kidney injury. Nephrotoxic drugs, contrast dye, and diuretics can worsen preexisting kidney dysfunction or act as an additive and/or synergistic insult to perioperative injury. A history of preoperative chronic kidney disease is the main risk factor for developing AKI, conferring as much as a 10-fold risk. However, beyond the preoperative renal function, the development of AKI is a complex phenomenon that involves a combination of patient-related and surgery-related factors.

Acute Kidney Injury Associated with Cardiac Surgery: a Comprehensive Literature Review

Objective

To comprehensively understand cardiac surgeryassociated acute kidney injury (CSA-AKI) and methods of prevention of such complication in cardiac surgery patients.

Methods

A comprehensive literature search was performed using the electronic database to identify articles describing acute kidney injury (AKI) in patients that undergone cardiac surgery. There was neither time limit nor language limit on the search. The results were narratively summarized.

Results

All the relevant articles have been extracted; results have been summarized in each related section. CSA-AKI is a serious postoperative complication and it can contribute to a significant increase in perioperative morbidity and mortality rates. Optimization of factors that can reduce CSA-AKI, therefore, contributes to a better postoperative outcome.

Conclusion

Several factors can significantly increase the rate of AKI; identification and minimization of such factors can lead to lower rates of CSA-AKI and lower perioperative morbidity and mortality rates.

Effect of dexmedetomidine on acute kidney injury after aortic surgery: a single-centre, placebo-controlled, randomised controlled trial

BACKGROUND

Acute kidney injury (AKI) is a frequent and serious complication after aortic surgery requiring cardiopulmonary bypass (CPB). Dexmedetomidine, a selective α-2 adrenoreceptor agonist, may reduce AKI because of its sympatholytic and anti-inflammatory effects against ischaemia-reperfusion injury. We investigated the effect of dexmedetomidine administration on AKI after aortic surgery requiring CPB in a placebo-controlled randomised controlled trial.

METHODS

A total of 108 patients were randomly assigned to an infusion of dexmedetomidine or saline at a rate of 0.4 μg kg-1 h-1 for 24 h starting after anaesthetic induction. The primary outcome was the incidence of AKI, as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The secondary outcomes included delirium and major morbidity. Safety outcomes were drug-related adverse events (bradycardia, hypotension).

RESULTS

AKI occurred in 7/54 (13%) subjects randomised to dexmedetomidine, compared with 17/54 (31%) subjects randomised to saline infusion (odds ratio=0.32; 95% confidence interval [CI], 0.12-0.86; P=0.026). Secondary outcomes, including stroke, mortality, and delirium, were similar between subjects randomised to dexmedetomidine (16/54 [30%] or saline control (22 [41%]; odds ratio=0.61 [95% CI, 0.28-1.36]). The incidence of bradycardia and hypotension was similar between groups (14/54 (26%) vs. 17/54 (32%) (odds ratio:0.76 (95%CI:0.33-1.76) and 29/54 (54%) vs. 36/54 (67%) (odds ratio:0.58 (95%CI:0.27-1.26), respectively). The length of hospital stay was shorter in the dexmedetomidine group (12 [10-17] days) vs saline control (15 [11-21] days; P=0.039).

CONCLUSIONS

Pre-emptive dexmedetomidine administration for 24 h starting after induction of anaesthesia reduced the incidence of AKI after aortic surgery requiring CPB, without any untoward side-effects related to its sedative or sympatholytic effects.

CLINICAL TRIAL REGISTRATION

NCT02607163 (www.

CLINICALTRIALS

gov).

The effect of repetitive exposure to intravenous anesthetic agents on the immunity in mice

Introduction: This study was designed to assess the effect of repetitive exposure to intravenous anesthetic agents on the immunity in mice. Materials and Methods: The mice were divided into six groups: three intravenous anesthetic agents groups (dexmedetomidine, midazolam and propofol groups), and three corresponding control groups (C_D, C_M, and C_P groups). The intravenous injections were administered once per day for 5 days. The immunity of mice was checked after the last intravenous injection. Histopathology and immunochemistry of liver and kidneys were evaluated. Cytokine levels in the blood was also checked. vs. evaluated with cytokine levels in the blood. Results: Cluster of differentiation (CD)4⁺ T cells were significantly less expressed in dexmedetomidine and propofol groups, compared with the corresponding control groups [34.08 ± 5.63% in the dexmedetomidine group vs. 59.74 ± 8.64% in the C_D group, p < 0.05; 25.28 ± 7.28% in the propofol group vs. 61.12 ± 2.70% in the C_p group, p < 0.05]. Apoptosis of CD4⁺ T cells was increased significantly in dexmedetomidine and propofol groups, compared with the corresponding control groups. Histopathological findings of liver and kidneys did not show any specific differences of any of three intravenous anesthetic agents groups with their corresponding control groups, although immunohistochemical examination indicated significantly lower expression of Toll-like receptor-4 from liver and kidneys in dexmedetomidine and propofol groups. The cytokine levels were not different between the groups. Conclusion: Repetitive exposure to dexmedetomidine and propofol reduced the expression of CD4⁺ T cells but did not induce any significant liver or kidney injuries.

Use of dexmedetomidine in pediatric cardiac anesthesia

PURPOSE OF REVIEW

In recent years, ultrafast-track anesthesia with on-table extubation and concepts of accelerated postoperative care have gained increasing support in pediatric congenital cardiac surgery. It is believed that such approaches might ideally combine economic benefits with a striving for continuous improvement of patient outcomes. The present review summarizes the role of dexmedetomidine (DEX) in this setting.

RECENT FINDINGS

DEX is a clinical multipurpose drug that mediates its diverse responses through the activation of α2-adrenoreceptors. In pediatric cardiac surgery it has various applications. Used as a premedication, DEX provides arousable sedation and anxiolysis. As an intraoperative adjunctive agent of balanced general anesthesia the primary objectives for its administration are attenuation of the neuro-humoral stress response and facilitation of early extubation. During ICU treatment DEX spares opioids, prevents the risk of postoperative delirium or emergence agitation and impacts on important patient-centered outcomes, such as duration of mechanical ventilation, restart of enteral nutrition or length of ICU stay.

SUMMARY

Due to a favorable mix of beneficial physiologic actions and a limited adverse effect profile, DEX is established in the perioperative pediatric cardiac surgery setting. However, evidence from high-quality randomized controlled trials on the effects of supplemental DEX on meaningful patient outcomes is scarce, and research on the role of DEX in providing cardioprotection, neuroprotection, or renoprotection is still at its beginning. DEX has developed to one of the main agents in the armamentarium of cardiac anesthesiologists and pediatric intensivists, but it should not be regarded as the new 'magic bullet'.