Lack of renoprotective effects of dopamine and furosemide during cardiac surgery

Association of Postoperative Serum Lactate Levels with Acute Kidney Injury in Mexican Patients Undergoing Cardiac Surgery

Acute kidney injury (AKI) is a highly prevalent and a critical complication of cardiac surgery (CS). Serum lactate (sLac) levels have consistently shown an association with morbimortality after CS. We performed a cross-sectional study including 264 adult patients that had a cardiac surgery between January and December 2020. Logistic regression analysis was performed to determine factors associated with AKI development. We measured the postoperative levels of sLac for all participants immediately after CS (T0) and at 4 h (T4) after the surgical intervention. A linear regression model was used to identify the factors influencing both sLac metrics. We identified four risk predictors of AKI; one was preoperative (atrial fibrillation), one intraoperative (cardiopulmonary bypass time), and two were postoperative (length of hospital stay and postoperative sLac). T0 and T4 sLac levels were higher among CS-AKI patients than in Non-CS-AKI patients. Postoperative sLac levels were significant independent predictors of CSA-AKI, and sLac levels are influenced by length of hospital stay, the number of transfused packed red blood cells, and the use of furosemide in CS-AKI patients. These findings may facilitate the earlier identification of patients susceptible to AKI after CS.

Cardiac surgery-Associated acute kidney injury - A narrative review

Cardiac Surgery-Associated Acute Kidney Injury (CSA-AKI) is a serious complication seen in approximately 20-30% of cardiac surgery patients. The underlying pathophysiology is complex, often involving both patient- and procedure related risk factors. In contrast to AKI occurring after other types of major surgery, the use of cardiopulmonary bypass comprises both additional advantages and challenges, including non-pulsatile flow, targeted blood flow and pressure as well as the ability to manipulate central venous pressure (congestion). With an increasing focus on the impact of CSA-AKI on both short and long-term mortality, early identification and management of high-risk patients for CSA-AKI has evolved. The present narrative review gives an up-to-date summary on definition, diagnosis, underlying pathophysiology, monitoring and implications of CSA-AKI, including potential preventive interventions. The review will provide the reader with an in-depth understanding of how to identify, support and provide a more personalized and tailored perioperative management to avoid development of CSA-AKI.

Hospitalized patients received furosemide undergoing acute kidney injury: the risk and prediction tool

PURPOSE

Furosemide, a frequently prescribed diuretic for managing congestive heart failure and edema, remains a topic of debate regarding its potential risk of inducing acute kidney injury (AKI) in patients. Consequently, this study aims to examine the occurrence of hospital-acquired AKI (HA-AKI) in hospitalized patients who are administered furosemide and to investigate potential risk factors associated with this outcome.

METHODS

This study encompassed a cohort of 22374 hospitalized patients who either received furosemide treatment or not from June 1, 2012, to December 31, 2017. Propensity score matching was employed to establish comparability between the two groups regarding covariates. Subsequently, a nomogram was constructed to predict the probability of AKI occurrence among patients who underwent furosemide treatment.

RESULTS

The regression analysis identified the single-day total dose of furosemide as the most significant factor for AKI, followed by ICU administration, estimated glomerular filtration rate, antibiotic, statin, NSAIDs, β-blockers, proton pump inhibitor, chronic kidney disease, and 7 other indicators. Subgroup analysis revealed a synergistic effect of furosemide with surgical operation, previous treatment with β-blockers, ACEI/ARB and antibiotics, leading to an increased risk of AKI when used in combination. Subsequently, a visually represented prognostic nomogram was developed to predict AKI occurrence in furosemide users. The predictive accuracy of the nomogram was assessed through calibration analyses, demonstrating an excellent agreement between the nomogram predictions and the actual likelihood of AKI, with a probability of 77.40%.

CONCLUSIONS

Careful consideration of factors such as dosage, concurrent medication use, and renal function of the patient is necessary for clinical practice when using furosemide. Our practical prognostic model for HA-AKI associated with furosemide use can be utilized to assist clinicians in making informed decisions about patient care and treatment.

The diuretic effect of adding aminophylline or theophylline to furosemide in pediatric populations: a systematic review

The diuretic effect of the combined furosemide and aminophylline/theophylline among pediatric patients remains unclear. The primary aim of this systematic review was to examine the clinical diuretic effects (urine output and fluid balance) of co-administration of furosemide and aminophylline/theophylline as compared to furosemide alone in pediatric population. Ovid MEDLINE, CENTRAL, and EMBASE were searched from its inception until March 2022 for observational studies and randomized controlled trials (RCTs) comparing the administration of furosemide versus furosemide and aminophylline/theophylline in pediatric population. Case reports, case series, commentaries, letters to editors, systematic reviews, and meta-analyses were excluded. Five articles with a total sample population of 187 patients were included in this systematic review. As compared to the furosemide alone, our pooled data demonstrated that co-administration of furosemide and aminophylline/theophylline was associated with higher urine output (mean difference: 2.91 [90% CI 1.54 to 4.27], p < 0.0001, I² = 90%) and a more negative fluid balance (mean difference - 28.27 [95% CI: - 46.21 to - 10.33], p = 0.002, I² = 56%) than those who received furosemide alone.

CONCLUSION

This is the first paper summarizing the evidence of combined use of furosemide with aminophylline/theophylline in pediatric population. Our systematic review demonstrated that the co-administration of furosemide and aminophylline/theophylline could potentially yield better diuretic effects of urine output and negative fluid balance than furosemide alone in pediatric patients with fluid overload. Given the substantial degree of heterogeneity and low level of evidence, future adequately powered trials are warranted to provide evidence regarding the combined use of aminophylline/theophylline and furosemide as diuretic in the pediatric population.

WHAT IS KNOWN

• Fluid overload is associated with poor prognosis for children in the intensive care unit. • The ineffective result of furosemide alone, even at high dose, as diuretic agent for children with diuretic resistant fluid overload in the intensive care unit.

WHAT IS NEW

• This is the first systematic review that compares furosemide alone and co-administration of furosemide and aminophylline/theophylline. • This paper showed potential benefit of co-administration of furosemide and aminophylline/theophylline promoting urine output and negative fluid balance compared to furosemide alone.

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.

Furosemide does not reduce the incidence of postoperative acute kidney injury in adult patients undergoing cardiac surgery: A PRISMA-compliant systematic review and meta-analysis

OBJECTIVE

Acute kidney injury (AKI) is a common complication of cardiac surgical patients, the occurrence of which is multifactorial. Furosemide is the most common loop diuretic and widely used in cardiac surgery to reduce fluid overload, increase tubular flow and urine output. It remains unknown whether furosemide affects the incidence or prognosis of cardiac surgery-induced acute kidney injury (CS-AKI). Therefore, the current study was performed to address this question.

METHODS

PubMed, Embase, Scopus, Cochrane Library, and Web of Science databases were searched for relevant studies. Primary outcomes of interest included postoperative CS-AKI incidence, need for renal replacement therapy (RRT) rate. Secondary outcomes of interest included postoperative serum creatinine (Scr) and blood urea nitrogen (BUN) levels, postoperative mechanical ventilation duration (MVD), length of stay (LOS) in intensive care unit (ICU) and in hospital, and mortality. The odds ratio (OR) and/or the weighted mean difference (WMD) with 95% confidence interval (CI) were used to pool the data.

RESULTS

Database search yielded six studies including 566 adult patients, and 283 patients were allocated into Group Furosemide and 283 into Group Control (Placebo). Heterogeneity between studies was deemed acceptable, and the publication bias was low. Meta-analysis suggested that furosemide administration in adult cardiac surgical patients had no effect on CS-AKI incidence (n = 4 trials; OR = 0.92; 95% CI: 0.37-2.30; p = .86; I²  = 57%) and need for RRT rate (n = 2 trials; OR = 4.13; 95% CI: 0.44-38.51; p = .21; I²  = 0%). Diversely, furosemide administration in adult cardiac surgical patients significantly decreased postoperative BUN level (n = 3 trials; WMD = 0.71; 95% CI: 0.10-1.33; p = .02; I²  = 0%), postoperative MVD (n = 2 trials; WMD = -3.13; 95% CI: -3.78 to -2.49; p < .00001; I²  = 0%) and postoperative LOS in ICU (n = 3 trials; WMD = -0.47; 95% CI: -0.76 to -0.18; p = .001; I²  = 0%). However, it had no significant impact on postoperative Scr level, postoperative LOS in hospital, and postoperative mortality.

CONCLUSION

This meta-analysis suggested that furosemide administration in adult cardiac surgical patients had no significant effect on CS-AKI incidence, need for RRT rate, postoperative Scr level, LOS in hospital and mortality, but could reduce postoperative BUN level, MVD, and LOS in ICU. As only a limited number of studies were included, these results should be interpreted carefully and cautiously. Future high-quality randomized controlled trials are needed to define the role of furosemide in CS-AKI prevention and management.

Strategies for post–cardiac surgery acute kidney injury prevention: A network meta-analysis of randomized controlled trials

Objects

Cardiac surgery is associated with acute kidney injury (AKI). However, the effects of various pharmacological and non-pharmacological strategies for AKI prevention have not been thoroughly investigated, and their effectiveness in preventing AKI-related adverse outcomes has not been systematically evaluated.

Methods

Studies from PubMed, Embase, and Medline and registered trials from published through December 2021 that evaluated strategies for preventing post–cardiac surgery AKI were identified. The effectiveness of these strategies was assessed through a network meta-analysis (NMA). The secondary outcomes were prevention of dialysis-requiring AKI, mortality, intensive care unit (ICU) length of stay (LOS), and hospital LOS. The interventions were ranked using the P-score method. Confidence in the results of the NMA was assessed using the Confidence in NMA (CINeMA) framework.

Results

A total of 161 trials (involving 46,619 participants) and 53 strategies were identified. Eight pharmacological strategies {natriuretic peptides [odds ratio (OR): 0.30, 95% confidence interval (CI): 0.19–0.47], nitroprusside [OR: 0.29, 95% CI: 0.12–0.68], fenoldopam [OR: 0.36, 95% CI: 0.17–0.76], tolvaptan [OR: 0.35, 95% CI: 0.14–0.90], N-acetyl cysteine with carvedilol [OR: 0.37, 95% CI: 0.16–0.85], dexmedetomidine [OR: 0.49, 95% CI: 0.32–0.76;], levosimendan [OR: 0.56, 95% CI: 0.37–0.84], and erythropoietin [OR: 0.62, 95% CI: 0.41–0.94]} and one non-pharmacological intervention (remote ischemic preconditioning, OR: 0.76, 95% CI: 0.63–0.92) were associated with a lower incidence of post–cardiac surgery AKI with moderate to low confidence. Among these nine strategies, five (fenoldopam, erythropoietin, natriuretic peptides, levosimendan, and remote ischemic preconditioning) were associated with a shorter ICU LOS, and two (natriuretic peptides [OR: 0.30, 95% CI: 0.15–0.60] and levosimendan [OR: 0.68, 95% CI: 0.49–0.95]) were associated with a lower incidence of dialysis-requiring AKI. Natriuretic peptides were also associated with a lower risk of mortality (OR: 0.50, 95% CI: 0.29–0.86). The results of a sensitivity analysis support the robustness and effectiveness of natriuretic peptides and dexmedetomidine.

Conclusion

Nine potentially effective strategies were identified. Natriuretic peptide therapy was the most effective pharmacological strategy, and remote ischemic preconditioning was the only effective non-pharmacological strategy. Preventive strategies might also help prevent AKI-related adverse outcomes. Additional studies are required to explore the optimal dosages and protocols for potentially effective AKI prevention strategies.

A Process for the Design and Development of Novel Bone Morphogenetic Protein-7 (BMP-7) Mimetics With an Example: THR-184

Growth Factors have been evaluated as therapeutic targets for the treatment of a broad spectrum of diseases. Because they are proteins with pleiotropic effects, the quest to harness their beneficial effects has presented challenges. Most Growth Factors operate at the extracellular-receptor level and have natural feedback mechanisms that modulate their effects. As proteins, they are difficult and expensive to manufacture. Frequently proteins must be administered parenterally, may invoke an immune response, and may be neutralized by naturally occurring inhibitors. To circumvent these limitations, we have undertaken an effort to develop mimetics for the Bone Morphogenetic Protein (BMP) signaling pathway effects that incorporate the beneficial effects, eliminate the deleterious effects, and thereby create effective drug-like compounds.To this end, we have designed and tested a family of small peptide BMP mimetics. The design used the three-dimensional structure of BMP-7 to identify likely active surface regions. Lead sequences were then optimized based on in vitro assays that examine the selective binding to BMP receptors, demonstrate the phosphorylation of Smad-1,5,8, detect anti-apoptosis and anti-inflammation, and block the epithelial to mesenchymal transition (EMT) in renal tubular epithelial cells. These sequences were further optimized using in vivo assays of the attenuation of acute kidney injury in a rat-model of unilateral clamp ischemic reperfusion. This process uses a Structure Variance Analysis algorithm (SVA) to identify structure/activity relationships. One member of this family, THR-184, is an agonist of BMP signaling and a potent antagonist of TGFβ signaling. This small peptide mimetic inhibits inflammation, apoptosis, fibrosis and reverses epithelial to mesenchymal transition (EMT) by regulating multiple signaling pathways involved in the cellular injury of multiple organs. Its effects have been shown to control Acute Kidney Injury (AKI). THR-184 has progressed through phase I and II clinical trials for the prevention of Cardio-Vascular Surgery (CVS) associated AKI. This work provides a roadmap for the development of other growth factor mimetics and demonstrates how we might harness their therapeutic potential.

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.

Relationship between intraoperative dopamine infusion and postoperative acute kidney injury in patients undergoing open abdominal aorta aneurysm repair

Background

Acute kidney injury (AKI) is one of the most common complications in patients undergoing open abdominal aortic aneurysm (AAA) repair. Dopamine has been frequently used in these patients to prevent AKI. We aimed to clarify the relationship between intraoperative dopamine infusion and postoperative AKI in patients undergoing open AAA repair.

Methods

We analyzed 294 patients who underwent open AAA repair at a single tertiary center from 2009 to 2018, retrospectively. The primary outcome was the incidence of postoperative AKI, determined by the Kidney Disease Improving Global Outcomes definition, after open AAA repair. Secondary outcomes included survival outcome, hospital and intensive care unit length of stay, and postoperative renal replacement therapy (RRT).

Results

Postoperative AKI occurred in 21.8% (64 out of 294 patients) The risk of postoperative AKI by intraoperative dopamine infusion was greater after adjusting for risk factors (odds ratio [OR] 2.56; 95% confidence interval [CI], 1.09–5.89; P = 0.028) and after propensity score matching (OR 3.22; 95% CI 1.12–9.24; P = 0.030). On the contrary, intraoperative norepinephrine use was not associated with postoperative AKI (use vs. no use; 19.3 vs. 22.4%; P = 0.615). Patients who used dopamine showed higher requirement for postoperative RRT (6.8 vs. 1.2%; P = 0.045) and longer hospital length of stay (18 vs. 16 days, P = 0.024).

Conclusions

Intraoperative dopamine infusion was associated with more frequent postoperative AKI, postoperative RRT, and longer hospital length of stay in patients undergoing AAA repair, when compared to norepinephrine. Further prospective randomized clinical trial may be necessary for this topic.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01624-6.

The Proximal Tubule as the Pathogenic and Therapeutic Target in Acute Kidney Injury

BACKGROUND

In 2004, the term acute kidney injury (AKI) was introduced with the intention of broadening our understanding of rapid declines in renal function and to replace the historical terms of acute renal failure and acute tubular necrosis (ATN). Despite this evolution in terminology, the mechanisms of AKI have stayed largely elusive with the pathophysiological concepts of ATN remaining the mainstay in our understanding of AKI.

SUMMARY

The proximal tubule (PT), having the highest mitochondrial content in the kidney and relying heavily on oxidative phosphorylation to generate ATP, is vulnerable to ischaemic insults and mitochondrial dysfunction. Histologically, pathological changes in the PT are more consistent than changes to the glomeruli or the loop of Henle in AKI. Physiologically, activation of tubuloglomerular feedback due to PT dysfunction leads to an increase in preglomerular afferent arteriole resistance and a reduction in glomerular filtration. Pharmacologically, frusemide - a drug commonly used in the setting of oliguric AKI - is actively secreted by the PT and its diuretic effect is compromised by its failure to be secreted into the urine and thus be delivered to its site of action at the loop of Henle in AKI. Increases in the urinary, but not plasma biomarkers, of PT injury within 1 h of shock suggest that the PT as the initiation pathogenic target of AKI.

KEY MESSAGE

Therapeutic agents targeting specifically the PT epithelial cells, in particular its mitochondria - including amino acid ergothioneine and superoxide scavenger MitoTEMPO - show great promises in ameliorating AKI.

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.

Incidence of acute kidney injury post cardiac surgery: a comparison of the AKIN and KDIGO criteria

Background and objectives

Data on urine output have not been routinely presented to define cardiac surgery-related acute kidney injury (AKI). We evaluated the incidence of AKI after cardiac surgery based on the AKIN and KDIGO criteria (considering serum creatinine concentration and urine output in the first 72 hours postoperatively) and compared the performance of the 2 criteria for AKI staging.

Methods

This was a prospective cohort study of adult patients undergoing coronary artery bypass grafting (CABG), valve replacement, or CABG + valve replacement between October 2017 and April 2018 at a single institution. Patients were excluded if baseline creatinine concentration (measured within 7 days before surgery) was ≥ 2.5 mg.dL^-1. Patients were evaluated for the development of AKI based on changes in urine output and serum creatinine concentration, measured daily from postoperative day 1 to 7, according to the AKIN and KDIGO criteria, which were then compared.

Results

A total of 198 patients were included. AKI occurred in 83.8% by AKIN and in 82.8% by KDIGO, when using both urine output and serum creatinine concentration as defining criteria. Using serum creatinine concentration alone, the incidence of AKI fell to 27.3% by AKIN and to 24.7% by KDIGO. A kappa coefficient of 0.98 was obtained between the AKIN and KDIGO criteria.

Conclusions

Almost perfect agreement was found between AKIN and KDIGO. AKI may be underdiagnosed after cardiac surgery if serum creatinine concentration is used as the only defining criterion. Our findings underscore the fundamental importance of using the urine output criterion in the assessment of patients at risk for AKI.

Arterial constriction after resection of neuroblastic tumors in children: Two-center retrospective study

BACKGROUND/PURPOSE

Neuroblastic tumors are the most common pediatric extracranial solid tumors in infants and very young children. Although, especially in newborns, there is an increasing number of situations in which observation alone is used, surgery remains an important step in the treatment of neuroblastoma but can be complicated by arterial vasospasm in the surgical field. The aim of this two-center retrospective study was to analyze the occurrence of arterial constriction as a complication of neuroblastic tumors resection.

METHODS

Medical records of patients who were treated surgically for neuroblastic tumors in the years 2012-2019 were reviewed.

RESULTS

For 8 years, 113 children were treated for neuroblastic tumors. The treatment included both primary and delayed surgery after initial chemotherapy carried out according to SIOPEN protocols. In 11 out of 113 cases (9.7%) local arterial constriction was observed. In 6 out of 11 cases an attempt was made to save the organ, however, two patients suffered from kidney atrophy, two other partial kidney infarctions, one child suffered from partial limb paresis, and another from brain ischemia and death.

CONCLUSIONS

Local arterial constriction constitutes a relatively common (10% of cases) and severe complication of neuroblastic tumors resection. Efficacy of local application of papaverine based on our experience remains unproven hence further research is warranted.

Potential Renoprotective Strategies in Adult Cardiac Surgery: A Survey of Society of Cardiovascular Anesthesiologists Members to Explore the Rationale and Beliefs Driving Current Clinical Decision-Making

OBJECTIVES

The authors sought to (1) characterize the rationale underpinning anesthesiologists' use of various perioperative strategies hypothesized to affect renal function in adult patients undergoing cardiac surgery, (2) characterize existing belief about the quality of evidence addressing the renal impact of these strategies, and (3) identify potentially renoprotective strategies for which anesthesiologists would most value a detailed, evidence-based review.

DESIGN

Survey of perioperative practice in adult patients undergoing cardiac surgery.

SETTING

Online survey.

PARTICIPANTS

Members of the Society of Cardiovascular Anesthesiologists (SCA).

INTERVENTIONS

None.

MEASUREMENTS & MAIN RESULTS

The survey was distributed to more than 2,000 SCA members and completed in whole or in part by 202 respondents. Selection of target intraoperative blood pressure (and relative hypotension avoidance) was the strategy most frequently reported to reflect belief about its potential renal effect (79%; 95% CI: 72-85). Most respondents believed the evidence supporting an effect on renal injury of intraoperative target blood pressure during cardiac surgery was of high or moderate quality. Other factors, including a specific nonrenal rationale, surgeon preference, department- or institution-level decisions, tradition, or habit, also frequently were reported to affect decision making across queried strategies. Potential renoprotective strategies most frequently requested for inclusion in a subsequent detailed, evidence-based review were intraoperative target blood pressure and choice of vasopressor agent to achieve target pressure.

CONCLUSIONS

A large number of perioperative strategies are believed to variably affect renal injury in adult patients undergoing cardiac surgery, with wide variation in perceived quality of evidence for a renal effect of these strategies.

Rationale and Design of Assessing the Effectiveness of Short-Term Low-Dose Lithium Therapy in Averting Cardiac Surgery-Associated Acute Kidney Injury: A Randomized, Double Blinded, Placebo Controlled Pilot Trial

Background: Burgeoning pre-clinical evidence suggests that therapeutic targeting of glycogen synthase kinase 3β (GSK3β), a convergence point of multiple cellular protective signaling pathways, confers a beneficial effect on acute kidney injury (AKI) in experimental models. However, it remains unknown if GSK3β inhibition likewise mitigates AKI in humans. Cardiac surgery associated acute kidney injury (CSA-AKI) poses a significant challenge for clinicians and currently the only treatment available is general supportive measures. Lithium, an FDA approved mood stabilizer, is the best-known GSK3β inhibitor and has been safely used for over half a century as the first line regimen to treat bipolar affective disorders. This study attempts to examine the effectiveness of short term low dose lithium on CSA-AKI in human patients.

Methods/Design: This is a single center, prospective, randomized, double blinded, placebo controlled pilot study on patients undergoing cardiac surgery with cardiopulmonary bypass. Patients will be randomized to receive a small dose of lithium or placebo treatment for three consecutive days. Renal function will be measured via creatinine as well as novel AKI biomarkers. The primary outcome is incidence of AKI according to Acute Kidney Injury Network (AKIN) criteria, and secondary outcomes include receipt of new dialysis, days on dialysis, days on mechanical ventilation, infections within 1 month of surgery, and death within 90 days of surgery.

Discussion: As a standard selective inhibitor of GSK3β, lithium has been shown to exert a beneficial effect on tissue repair and regeneration upon acute injury in multiple organ systems, including the central nervous system and hematopoietic system. In experimental AKI, lithium at small doses is able to ameliorate AKI and promote kidney repair. Successful completion of this study will help to assess the effectiveness of lithium in CSA-AKI and could potentially pave the way for large-scale randomized trials to thoroughly evaluate the efficacy of this novel regimen for preventing AKI after cardiac surgery.

Trial Registration: This study was registered prospectively on the 17th February 2017 at ClinicalTrials.gov (NCT03056248, https://clinicaltrials.gov/ct2/show/NCT03056248?term=NCT03056248&draw=2&rank=1).

Comprehensive Comparisons among Inotropic Agents on Mortality and Risk of Renal Dysfunction in Patients Who Underwent Cardiac Surgery: A Network Meta-Analysis of Randomized Controlled Trials

Several kinds of inotropes have been used in critically ill patients to improve hemodynamics and renal dysfunction after cardiac surgery; however, the treatment strategies for reducing mortality and increasing renal protection in patients who underwent cardiac surgery remain controversial. Therefore, we performed a comprehensive network meta-analysis to overcome the lack of head-to-head comparisons. A systematic database was searched up to 31 December 2020, for randomized controlled trials that compared different inotropes on mortality outcomes and renal protective effects after cardiac surgery. A total of 29 trials were included and a frequentist network meta-analysis was performed. Inconsistency analyses, publication bias, and subgroup analyses were also conducted. Compared with placebo, use of levosimendan significantly decreased the risks of mortality (odds ratio (OR): 0.74; 95% confidence interval (CI): 0.56–0.97) and risk of acute renal injury (OR: 0.61; 95% CI: 0.45–0.82), especially in low systolic function patients. Use of levosimendan also ranked the best treatment based on the P-score (90.1%), followed by placebo (64.5%), milrinone (49.6%), dopamine (49.5%), dobutamine (29.1%), and fenoldopam (17.0%). Taking all the available data into consideration, levosimendan was a safe renal-protective choice for the treatment of patients undergoing cardiac surgery, especially for those with low systolic function.

Angiotensin-Converting Enzyme Inhibitor/Receptor Blocker, Diuretic, or Nonsteroidal Anti-inflammatory Drug Use After Major Surgery and Acute Kidney Injury: A Case-Control Study

BACKGROUND

Acute kidney injury (AKI) is common after surgery and associated with increased mortality, costs, and lengths of hospitalization. We examined associations between angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB), diuretic, or nonsteroidal anti-inflammatory drug (NSAID) use after major surgery and AKI.

MATERIALS AND METHODS

We conducted a nested case-control study of patients who underwent major cardiac, thoracic, general, or vascular surgery in Calgary, Alberta, Canada. Cases with AKI were matched on age, gender, and surgery type with up to five controls without AKI within 30-d after surgery. Adjusted odds ratios (ORs) for AKI were determined based on postoperative administration of ACEIs/ARBs, diuretics, or NSAIDs.

RESULTS

Among 33,648 patients in the cohort, 2911 cases with AKI were matched to 9309 controls without AKI. Postoperative diuretic [OR = 1.96; 95% confidence interval (CI) = 1.68-2.29], but not ACEI/ARB (OR = 0.83; 95% CI = 0.72-0.95) or NSAID (OR = 1.12; 95% CI = 0.96-1.31), use was independently associated with higher odds of AKI (including stages 1 and 2/3 AKI) after all types of major surgery. There were increased adjusted odds of AKI 1 to 5 d after first exposure to diuretics and 1 d after first exposure to NSAIDs (but not after later exposures). Relationships between ACEI/ARB use and AKI varied by surgery type (p-interaction = 0.004), with lower odds of AKI observed among ACEI/ARB use after cardiac surgery (OR = 0.70; 95% CI = 0.57-0.81), but no difference after other major surgeries.

CONCLUSIONS

Postoperative administration of diuretics and NSAIDs was associated with increased odds of AKI after major surgery. These findings characterize potentially modifiable medication exposures associated with AKI after surgery.

Dopamine and Drip Lasix in Pediatrics with Oliguria: A Clinical Trial Study

Background: Urine volume less than 1 mL/kg/h is called oliguria. The treatment of these patients is very important. Objectives: This study aimed to compare efficacy of dopamine and drip Lasix in children with oliguria. Methods: This study was performed as a clinical trial in the NICU, PICU, neonatal and pediatric wards of Amirkabir hospital in Arak. Children with oliguria with less than 1 mL/kg/h during treatment were considered the study group. Sixty children who met the inclusion criteria were selected and randomly divided into two groups, including 30 children in the dopamine group and 30 children in the Lasix group. In the dopamine group, the drug was administered at a dose of 3 µg/kg/min, in the second group, drip Lasix was administered at a dose of 0.05 mg/kg/h. Results: In this evaluation, after evaluating the patients in both groups, it was observed that mean ± SD of age was 2.76 ± 1.85 years, and 51.7% of children have female gender (P = 0.438). The mean ± SD of creatinine in children after receiving dopamine and drip Lasix was 0.87 ± 0.2 mg/dl (P = 0.0001) and 0.84 ± 0.17 mg/dl (P = 0.000), respectively. Conclusions: Both drip Lasix and dopamine improved the condition of patients with oliguria. In addition, there was no statistically significant difference between these two drugs, so both drugs could improve the condition of patients.

Preoperative use of furosemide may increase the incidence of acute kidney injury after coronary artery bypass grafting: a propensity score-matched study

Objectives

Furosemide is usually administered before the Coronary artery bypass grafting (CABG) to improve water–sodium retention. However, no final conclusions are available on the postoperative renal outcome of furosemide. We evaluated the effect of preoperative furosemide on acute kidney injury (AKI) after CABG.

Methods

We recorded the use of furosemide 14 days before surgery in all patients who underwent CABG from 2016 to 2017. Patients were divided into furosemide (F) group and non-furosemide (NF) group according to preoperative use of furosemide. A 1:1 propensity score matching was performed. Multivariate analyses were conducted to determine risk factors for AKI after CABG.

Results

Overall, 974 patients were included in the study, of which 82 cases were complicated with postoperative AKI. The incidence of AKI was significantly increased in F group than NF group (28.9% vs. 7.4%, p = 0.000). After adjusting for risk factors, the incidence of AKI in the F group was 5.34 times more than the NF group (95% confidence interval [CI] 2.45–11.64; p = 0.000). The incidence of AKI increased significantly when the cumulative dosage of furosemide exceeded 110 mg (odds ratio [OR] 6.23; 95% CI 2.07–18.74, p = 0.001) and 250 mg (OR 8.31; 95% CI 2.87–24.02, p = 0.000). After the propensity-matching group analysis, same results were obtained.

Conclusions

The incidence of AKI after CABG was related to the use of preoperative furosemide, and it increased exponentially with the increase of cumulative dose of furosemide. This provides guidance for the dose of preoperative furosemide.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11748-021-01599-0.

Markers of Poor Prognosis in Patients Requiring Continuous Renal Replacement Therapy After Cardiac Surgery

OBJECTIVE

Acute kidney injury requiring renal replacement therapy after cardiac surgery has an incidence of 2% to 15%, and mortality in affected patients approximates 50%. The authors aimed to study the determinants of poor prognosis in patients receiving continuous renal replacement therapy (CRRT) after cardiac surgery.

DESIGN

Retrospective, observational single-center study.

SETTING

Tertiary care, university hospital.

PARTICIPANTS

Cardiac surgery patients admitted to the intensive care unit (ICU) needing postoperative CRRT between January 1, 2010, and September 31, 2019.

INTERVENTIONS

Predictors of mortality were examined using groupwide comparisons between ICU survivors versus nonsurvivors and univariate and multivariate Cox proportional hazards models.

RESULTS

During the study period, 67 cardiac surgery patients without prior maintenance dialysis required CRRT postoperatively. ICU mortality was 47.7% and 90-day mortality was 58.2%. Only 37.3% of patients were alive at 1 year after surgery. Blood lactate at the start of dialysis was the most significant predictor of ICU and overall mortality. Eighty-seven percent of patients with lactate >3 mmol/L died in the ICU compared with 27.3% of patients with lactate ≤3 mmol/L (p < 0.0001). In patients with lactate exceeding 5.3 mmol/L, ICU mortality was 100%. In a stepwise multivariate Cox proportional hazards model, the association with mortality remained significant for lactate at the start of CRRT (per 1 mmol/L, hazard ratio [HR] 1.19 [95% confidence interval {CI} 1.11-1.28], p < 0.0001), troponin T on the first postoperative morning (per 0.1 µg/L, HR 1.004 [95% CI 1.001-1.008], p = 0.01), and 72-hour fluid balance (per 1000 mL, HR 1.12 [95% CI 1.04-1.21], p = 0.005).

CONCLUSION

Blood lactate at the start of dialysis was the most significant predictor of ICU and overall mortality in patients with CRRT after cardiac surgery.

Strategies to Reduce Perioperative Nephrotoxicity

Postoperative acute kidney injury (AKI) is a common complication of surgery that is associated with significant adverse outcomes, including increased morbidity and mortality. The perioperative burden of AKI risk factors is complex and potentially large, including high-risk nephrotoxic medications, hypotension, hypovolemia, radiologic contrast, anemia, and surgery-specific factors. Understanding the pathogenesis, risk factors, and potential cumulative impact of perioperative nephrotoxic exposures is particularly important in the prevention and reduction of perioperative AKI. This review outlines the possible strategies to reduce perioperative nephrotoxicity and the development of postoperative AKI.

Recommendations for Preoperative Assessment and Shared Decision-Making in Cardiac Surgery

Purpose of review

Recommendations about shared decision-making and guidelines on preoperative evaluation of patients undergoing non-cardiac surgery are abundant, but respective recommendations for cardiac surgery are sparse. We provide an overview of available evidence.

Recent findings

While there currently is no consensus statement on the preoperative anesthetic evaluation and shared decision-making for the adult patient undergoing cardiac surgery, evidence pertaining to specific organ systems is available.

Summary

We provide a comprehensive review of available evidence pertaining to preoperative assessment and shared decision-making for patients undergoing cardiac surgery and recommend a thorough preoperative workup in this vulnerable population.

Importance of sodium-glucose cotransporter 2 inhibitor use in diabetic patients with acute heart failure

BACKGROUND

It is known that once heart failure occurs in older patients with diabetes, the overall prognosis is extremely poor. We investigated whether early initiation of SGLT2 inhibitor therapy after admission was beneficial for diabetic patients requiring inpatient treatment for acute heart failure.

METHODS

We retrospectively assessed consecutive patients with comorbid diabetes who were admitted to the Department of Cardiology in Tosei General Hospital for treatment of acute heart failure. Patients were divided into two groups: those who initiated SGLT2 inhibitor therapy (SGLT2 inhibitor group; mean age: 73 ± 9 years) and those who did not receive the inhibitors during hospitalization (conventional treatment group; mean age: 75 ± 10 years).

RESULTS

No intergroup differences were observed in the distribution of either the severity or classes of heart failure on admission. Glycosylated hemoglobin levels were significantly higher in the SGLT2 inhibitor group (HbA1c: 8.1% ± 0.8%) than in the conventional treatment group (HbA1c: 7.1% ± 0.8%) (p = 0.003). After admission, patients in both groups recovered equally well, and in almost the same period of time, before discharge. The rate of diuretics use at the time of discharge in the SGLT2 inhibitor group (n = 8, 67%) was significantly lower than that in the conventional treatment group (n = 19, 100%) (p = 0.016). In particular, the dose of loop diuretics in the conventional treatment group was 34 ± 4 mg/day while that in the SGLT2 inhibitor group was significantly lower at 13 ± 5 mg/day (p = 0.008). During hospitalization, the incidence of acute kidney injury was significantly higher in the conventional treatment group (n = 11, 58%) than in the SGLT2 inhibitor group (n = 2, 16%) (p = 0.031).

CONCLUSIONS

For the treatment and management of heart failure in patients with diabetes, early initiation of SGLT2 inhibitor therapy appears to be effective.

Impact of furosemide on mortality and the requirement for renal replacement therapy in acute kidney injury: a systematic review and meta-analysis of randomised trials

Objective

To examine the impact of furosemide on mortality and the need for renal replacement therapy (RRT) in adult patients with acute kidney injury (AKI) based on current evidence.

Data sources

PubMed (Medline) and Embase were searched from 1998 to October 2018.

Study selection

We retrieved data from randomised controlled trials comparing prevention/treatment with furosemide at any stage of AKI with alternative treatment/standard of care/placebo. The outcome was short-term mortality and the requirement for RRT, when applicable.

Data extraction

Two reviewers independently extracted appropriate data. PRISMA guidelines were followed for data preparation and reporting.

Data synthesis

We identified 20 relevant studies (2608 patients: 1330 in the treatment arm and 1278 in the control arm). Heterogeneity between studies was deemed acceptable, and the publication bias was low. Furosemide had neither an impact on mortality (OR = 1.015; 95% CI 0.825–1.339) nor the need for RRT (OR = 0.947; 95% CI 0.521–1.721). Furosemide had also no effect on the outcomes in strata defined by intervention strategy (prevention/treatment), AKI origin (cardio-renal syndrome, post-cardiopulmonary bypass, critical illness), control arm comparator (RRT, saline/placebo/standard of care) and its dose (< 160/≥ 160 mg) (p > 0.05 for all). Subjects who received furosemide with matched hydration in prevention of contrast-induced nephropathy (CIN) had a less frequent need for RRT (OR = 0.218; 95% CI 0.05–1.04; p = 0.055).

Conclusions

Furosemide administration has neither an impact on mortality nor the requirement for RRT. Patients at risk of CIN may benefit from furosemide administration. Further well-designed RCTs are needed to verify these findings.

Electronic supplementary material

The online version of this article (10.1186/s13613-019-0557-0) contains supplementary material, which is available to authorized users.

Acute Kidney Injury Following Cardiothoracic Surgery

This article reviews acute kidney injury following cardiothoracic surgery, addressing the full spectrum of the perioperative environment including preoperative, intraoperative, and postoperative factors for acute kidney injury. Topics discussed include pathophysiology, risk prediction scoring, diagnosis, prevention, treatment, and new directions for research.

Cardiopulmonary Bypass and AKI: AKI Is Bad, So Let's Get Beyond the Diagnosis

It is now well-established that AKI is a serious and common complication following cardiopulmonary bypass (CPB) in both children and adults, adverse outcomes may occur in the short term as well as long term, with higher incidence of chronic kidney disease, increased healthcare utilization and higher frequency of cardiovascular events in patients who develop post-CPB AKI. Despite the advances in our understanding of the pathogenesis of the disease and the improvement in diagnostic tools, our therapeutic options have remained suboptimal. There are multiple challenges in designing a clinical therapeutic AKI trial, including a multi-factorial etiology, difficulties with accurate diagnosis of AKI, achievement of adequate study power, and determination of appropriate outcomes. We are often left with "supportive" care. Studies have shown some benefit to AKI bundles, but adherence to bundle guidelines may be suboptimal. Current best practices should include maintenance of adequate renal perfusion pressure and avoidance of fluid overload, with consideration of early renal replacement therapy. Finally, multi-center trials of AKI therapies are crucial to finding treatment for this devastating complication of CPB.

The Japanese clinical practice guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention is necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

Effectiveness of contrast-associated acute kidney injury prevention methods; a systematic review and network meta-analysis

BACKGROUND

Different methods to prevent contrast-associated acute kidney injury (CA-AKI) have been proposed in recent years. We performed a mixed treatment comparison to evaluate and rank suggested interventions.

METHODS

A comprehensive Systematic review and a Bayesian network meta-analysis of randomised controlled trials was completed. Results were tabulated and graphically represented using a network diagram; forest plots and league tables were shown to rank treatments by the surface under the cumulative ranking curve (SUCRA). A stacked bar chart rankogram was generated. We performed main analysis with 200 RCTs and three analyses according to contrast media and high or normal baseline renal profile that includes 173, 112 & 60 RCTs respectively.

RESULTS

We have included 200 trials with 42,273 patients and 44 interventions. The primary outcome was CI-AKI, defined as ≥25% relative increase or ≥ 0.5 mg/dl increase from baseline creatinine one to 5 days post contrast exposure. The top ranked interventions through different analyses were Allopurinol, Prostaglandin E1 (PGE1) & Oxygen (0.9647, 0.7809 & 0.7527 in the main analysis). Comparatively, reference treatment intravenous hydration was ranked lower but better than Placebo (0.3124 VS 0.2694 in the main analysis).

CONCLUSION

Multiple CA-AKI preventive interventions have been tested in RCTs. This network evaluates data for all the explored options. The results suggest that some options (particularly allopurinol, PGE1 & Oxygen) deserve further evaluation in a larger well-designed RCTs.

Goal-directed therapy in patients with early acute kidney injury: a multicenter randomized controlled trial

OBJECTIVES

Acute kidney injury is associated with many conditions, and no interventions to improve the outcomes of established acute kidney injury have been developed. We performed this study to determine whether goal-directed therapy conducted during the early stages of acute kidney injury could change the course of the disease.

METHODS

This was a multicenter prospective randomized controlled study. Patients with early acute kidney injury in the critical care unit were randomly allocated to a standard care (control) group or a goal-directed therapy group with 8h of intensive treatment to maximize oxygen delivery, and all patients were evaluated during a period of 72h. ClinicalTrials.gov: NCT02414906.

RESULTS

A total of 143 patients were eligible for the study, and 99 patients were randomized. Central venous oxygen saturation was significantly increased and the serum lactate level significantly was decreased from baseline levels in the goal-directed therapy group (p=0.001) compared to the control group (p=0.572). No significant differences in the change in serum creatinine level (p=0.96), persistence of acute kidney injury beyond 72h (p=0.064) or the need for renal replacement therapy (p=0.82) were observed between the two groups. In-hospital mortality was significantly lower in the goal-directed therapy group than in the control group (33% vs. 51%; RR: 0.61, 95% CI: 0.37-1.00, p=0.048, number needed to treat=5).

CONCLUSIONS

Goal-directed therapy for patients in the early stages of acute kidney injury did not change the disease course.

Early postoperative change in serum creatinine predicts acute kidney injury after cardiothoracic surgery: a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) is one of the most severe complications after cardiothoracic surgery (CTS). However, diagnosis of AKI by elevation of serum creatinine (SCr) misses a critical time period for prevention and treatment of AKI. We have observed that patients who develop AKI show a smaller SCr decrease after CTS than those without AKI. Hence, we hypothesized that the magnitude of the SCr change (ΔSCr) measured early after CTS can predict subsequent AKI.

METHODS

We conducted a retrospective analysis from January 2014 to December 2016 to examine the association of ΔSCr with AKI. ΔSCr was calculated as follows: (early postoperative SCr on intensive care unit [ICU] admission) - (preoperative SCr). Established risk factors and demographics were included in the multivariate-adjusted logistic regression model. AKI was defined by SCr criteria of the Kidney Disease: Improving Global Outcomes group.

RESULTS

Among 252 patients who underwent CTS, 69 developed AKI. The median ΔSCr was - 0.14 mg/dL (range - 0.96-0.45). Patients were divided into three groups based on ΔSCr: Group 1, ≤ - 0.2 mg/dL (n = 84); Group 2, > - 0.2 to < - 0.1 mg/dL (n = 76); and Group 3, ≥ - 0.1 mg/dL (n = 92). In the multivariate analysis, Group 3 had a significantly higher incidence of AKI than Group 1 (odds ratio, 7.34; 95% confidence interval 2.55-23.3). ΔSCr was an independent risk factor for AKI (odds ratio for every 0.1-mg/dL increase in ΔSCr, 1.55; 95% confidence interval 1.23-1.97).

CONCLUSIONS

A minor change in the SCr level early after CTS can predict subsequent AKI just after ICU admission.

The Japanese Clinical Practice Guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention are necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

Comparison of the renoprotective effect of dexmedetomidine and dopamine in high-risk renal patients undergoing cardiac surgery: A double-blind randomized study

OBJECTIVE

The purpose of the current study was to compare the renoprotective effects of continuous infusion of dexmedetomidine and dopamine in high-risk renal patients undergoing cardiac surgery.

DESIGN

A double-blind randomized study.

SETTING

Cardiac Centers.

PATIENTS

One hundred and fifty patients with baseline serum creatinine level ≥1.4 mg/dl were scheduled for cardiac surgery with cardiopulmonary bypass.

INTERVENTION

The patients were classified into two groups (each = 75): Group Dex - the patients received a continuous infusion of dexmedetomidine 0.4 μg/kg/h without loading dose during the procedure and the first 24 postoperative hours and Group Dopa - the patients received a continuous infusion of dopamine 3 μg/kg/min during the procedure and the first 24 postoperative hours.

MEASUREMENTS

The monitors included serum creatinine, creatinine clearance, blood urea nitrogen, and urine output.

MAIN RESULTS

The creatinine levels and blood urea nitrogen decreased at days 1, 2, 3, 4, and 5 in Dex group and increased in patients of Dopa group (P < 0.05). The creatinine clearance increased at days 1, 2, 3, 4, and 5 in Dex group and decreased in patients of Dopa group (P < 0.05). The amount of urine output was too much higher in the Dex group than the Dopa group (P < 0.05).

CONCLUSIONS

The continuous infusion of dexmedetomidine during cardiac surgery has a renoprotective effect and decreased the deterioration in the renal function in high-risk renal patients compared to the continuous infusion of dopamine.

Intermittent furosemide administration in patients with or at risk for acute kidney injury: Meta-analysis of randomized trials

Background

Furosemide is the most common loop diuretic used worldwide. The off-label administration of furosemide bolus(es) for the prevention or to reverse acute kidney injury (AKI) is widespread but not supported by available evidence. We conducted a meta-analysis of randomized trials (RCTs) to investigate whether bolus furosemide to prevent or treat AKI is detrimental on patients’ survival.

Methods

Electronic databases were searched through October 2017 for RCTs comparing bolus furosemide administration versus any comparator in patients with or at risk for AKI. The primary endpoint was all-cause longest follow-up mortality. Secondary endpoints included new or worsening AKI, receipt of renal replacement therapy, length of hospital stay, and peak serum creatinine after randomization.

Results

A total of 28 studies randomizing 3,228 patients were included in the analysis. We found no difference in mortality between the two groups (143/892 [16%] in the furosemide group versus 141/881 [16%] in the control group; odds ratio [OR], 0.84; 95% confidence interval [CI], 0.63 to 1.13; p = 0.25). No significant differences in secondary outcomes were found. A significant improvement in survival was found in the subgroup of patients receiving furosemide bolus(es) as a preventive measure (43/613 [7.0%] versus 67/619 [10.8%], OR 0.62; 95% CI, 0.41 to 0.94; p = 0.03)

Conclusions

Intermittent furosemide administration is not associated with an increased mortality in patients with or at risk for AKI, although it may reduce mortality when used as a preventive measure. Future high-quality RCTs are needed to define the role of loop diuretics in AKI prevention and management.

Trial registration

The study protocol was registered on PROSPERO database for systematic reviews (Registration no. CRD42017078607 – http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42017078607).

[Prevention of acute kidney injury in critically ill patients : Recommendations from the renal section of the DGIIN, ÖGIAIN and DIVI]

BACKGROUND

Acute kidney injury (AKI) has both high mortality and morbidity.

OBJECTIVES

To prevent the occurrence of AKI, current recommendations from the renal section of the DGIIN (Deutschen Gesellschaft für Internistische Intensivmedizin und Notfallmedizin), ÖGIAIN (Österreichischen Gesellschaft für Internistische und Allgemeine Intensivmedizin und Notfallmedizin) and DIVI (Deutschen Interdisziplinären Vereinigung für Intensiv- und Notfallmedizin) are stated.

MATERIALS AND METHODS

The recommendations stated in this paper are based on the current Kidney Disease Improving Global Outcomes (KDIGO) guidelines, the published statements of the "Working Group on Prevention, AKI section of the European Society of Intensive Care Medicine" and the expert knowledge and clinical experience of the authors.

RESULTS

Currently there are no approved clinically effective drugs for the prevention of AKI. Therefore the mainstay of prevention is the optimization of renal perfusion by improving the mean arterial pressure (>65 mm Hg, higher target may be considered in hypertensive patients). This can be done by vasopressors, preferably norepinephrine and achieving or maintaining euvolemia. Hyperhydration that can lead to AKI itself should be avoided. In patients with maintained diuresis this can be done by diuretics that are per se no preventive drug for AKI. Radiocontrast enhanced imaging should not be withheld from patients at risk for AKI; if indicated, however, the contrast media should be limited to the smallest possible volume.

Prevention of Acute Renal Failure: Role of Vaso-Active Drugs, Mannitol and Diuretics

Evidence exists that acute renal failure (ARF) independently increases mortality risk in critically-ill patients. Therefore prevention of ARF seems of paramount importance. Preservation of renal blood flow and (sufficient) perfusion pressure favourably influences the prevention of renal function deterioration in the critically-ill septic patient. The first step to achieve this is infusion of fluids, either crystalloids or colloids, with the aim of optimal fluid resuscitation. Although “optimal fluid resuscitation” is poorly defined, in clinical practice it can be considered as the point where a certain preload is obtained, after which no further increase of cardiac output is observed with further fluid infusion. Vasoactive drugs can be added to this regimen in case of insufficient restoration of flow and especially perfusion pressure. The addition of norepinephrine can be of value if high doses of dopamine fail to restore perfusion pressure. No evidence exists that low-dose dopamine prevents renal failure and, therefore, dopamine should not be given for this indication. The use of diuretic agents can be harmful, as indicated by observational and cohort studies. Although mannitol flushes out intratubular casts and increases tubular flow, which is favorable in myoglobinuria or hemoglobinuria, so far no well designed clinical studies have demonstrated its efficacy in ARF. In conclusion, there is currently no convincing evidence for any benefit from diuretic agents and/or (low dose) dopamine in the prevention of ARF. High quality intenisve care and avoidance of harm is, therefore, the current standard of the prevention of ARF.

Prevention of Cardiac Surgery-Associated Acute Kidney Injury

Numerous strategies have been evaluated to prevent early CSA-AKI. Although correction of hemodynamic problems is paramount, there are no clinical studies that compare different hemodynamic management or monitoring strategies with regard to their effect on kidney function. Pharmacologic strategies including diuretics, different classes of vasodilators and drugs with anti-inflammatory effects such as N-acetyl-cysteine, do not appear to be effective. Most of the studies are underpowered and use physiological rather than clinical endpoints. Further trials are warranted with fenoldopam and nesiritide (rhBNP). Observational and underpowered randomized studies show beneficial renal effects of off-pump technique and avoidance of aortic manipulation. There is very limited evidence for preoperative fluid loading and preemptive RRT. Potentially nephrotoxic agents should be used with caution in patients at risk of CSA-AKI. Tranexamic acid or aminocaproic acid should be preferred over aprotinin. No pharmacologic intervention has been adequately tested in the prevention of late CSA-AKI. A single-center study, including a predominance of patients after cardiac surgery, showed a decrease of kidney injury with tight glycemic control.