Prevention of acute kidney injury and protection of renal function in the intensive care unit. Expert opinion of the Working Group for Nephrology, ESICM

Effect of care bundles for acute kidney injury: A systematic review and meta-analysis

PURPOSE

Acute kidney injury (AKI) is frequent among in-hospital patients with high incidence and mortality. Implementing a series of evidence-based AKI care bundles may improve patient outcomes by reducing changeable standards of care. The aim of this meta-analysis was therefore to appraise the influences of AKI care bundles on patient outcomes.

MATERIALS AND METHODS

We explored three international databases (PubMed, Embase, and Cochrane Central Register of Controlled Trials) and two Chinese databases (Wanfang Data and China National Knowledge Infrastructure) for studies from databases inception until November 30, 2022, comparing the impact of different AKI care bundles with usual standards of care in patients with or at risk for AKI. The study quality of non-randomized controlled trials and randomized controlled trials was evaluated by the NIH Study Quality Assessment Tool and the Cochrane risk of bias tool. Heterogeneity between studies was appraised by Cochran's Q test and I2 statistics. The possible origins of heterogeneity between studies were assessed adopting Meta-regression and subgroup analyses. Funnel plot asymmetry and Egger regression and Begg correlation tests were performed to discover potential publication bias. Data analysis was completed by software (RevMan 5.3 and Stata 15.0). The primary outcome was short- or long-term mortality. The secondary outcomes involved the incidence and severity of AKI.

RESULTS

Sixteen studies containing 25,690 patients and 25,903 AKI episodes were included. In high-risk AKI patients determined by novel biomarkers, electronic alert or risk prediction score, the application of AKI care bundles significantly reduced the AKI incidence (OR, 0.71; 95% CI, 0.53-0.96; p = 0.02; I2 = 84%) and AKI severity (OR, 0.59; 95% CI, 0.39-0.89; p = 0.01; I2 = 65%). No strong evidence is available to prove that care bundles can significantly reduce mortality (OR, 1.16; 95% CI, 0.58-2.30; p = 0.68; I2 = 97%).

CONCLUSIONS

The introduction of AKI care bundles in routine clinical practice can effectively improve the outcomes of patients with or at-risk of AKI. However, the accumulated evidence is limited and not strong enough to make definite conclusions.

An online-predictive model of acute kidney injury after pancreatic surgery

OBJECTIVE

Acute kidney injury(AKI) after pancreatic surgery is associated with increased mortality, longer hospital stays and poor prognosis. This study aims to identify the risk factors and establish an easy-to-use prediction calculator by the nomogram to predict the risk of AKI after pancreatic surgery.

METHODS

From January 2016 to June 2018, 1504 patients who underwent pancreatic surgery in our center were included in this retrospective analysis and randomly assigned to primary (1054 patients) and validation (450 patients) cohorts. The independent risk factors of AKI were identified using univariate and multivariate analyses. A risk-predicted nomogram for AKI was developed through multivariate logistic regression analysis in the primary cohort while the nomogram was evaluated in the validation cohort. Nomogram discrimination and calibration were assessed using C-index and calibration curves in the primary and validation cohorts. The clinical utility of the final nomogram was evaluated using decision curve analysis.

RESULTS

The overall incidence of AKI after pancreatic surgery was 5.3% (79/1504). Independent risk factors including smoking history, cardiovascular disease, ASA score, baseline eGFR, bilirubin＞2 ​mg/dL, undergoing pancreaticoduodenectomy, and intraoperative blood loss＞400 ​mL were identified by multivariate analysis. Nomogram revealed moderate discrimination and calibration in estimating the risk of AKI, with an unadjusted C-index of 0.79 (95 %CI, 0.73-0.85). Application of the nomogram in the validation cohort provided moderate discrimination (C-index,0.80 [95% CI, 0.72-0.88]) and good calibration. Besides, the decision curve analysis (DCA) confirmed the clinical usefulness of the nomogram.

CONCLUSIONS

An easy-to-use online prediction calculator comprised of preoperative and intraoperative factors was able to individually predict the occurrence risk of AKI among patients with pancreatic surgery, which may help identify reasonable risk judgments and develop proper treatment strategies to a certain extent.

Natural products applied in acute kidney injury treatment: polymer matters

Acute kidney injury (AKI) is a global health threat due to its high morbidity and mortality. There is still a lack of effective therapeutic methods to deal with AKI clinically. Natural products with outstanding accessibility and bioactivity are potential candidates for AKI treatment. Natural product-based prodrugs or nano-structures with improved properties are frequently fabricated for maximizing bioavailability and decreasing side effects, in which natural polymers are selected as carriers, or natural drugs are loaded as cargos on designed polymers. In this review, the etiologies of AKI are briefly presented, and emerging natural products delivered rationally for AKI therapy, as either carriers or cargos, are both introduced. Moreover, the challenges of the future development of nature-based nanodrugs or prodrugs for AKI have also been discussed.

The intellectual base and global trends in contrast-induced acute kidney injury: a bibliometric analysis

Contrast-induced acute kidney injury (CI-AKI) has become the third leading cause of hospital-acquired kidney injury. A comprehensive analysis of the current state of research in the field of CI-AKI will help to reveal trends and hot topics in the field. To date, there are no published bibliometric analyses related to CI-AKI studies. Here, we analyze the relevant literature since the emergence of the concept and provide valuable insights. The literature was collected from the Web of Science Core Collection. The data were analyzed visually using CiteSpace and VOSviewer software. We collected a total of 4775 papers, with the United States and Guangdong Acad Med Sci as the major publishing powers in terms of country/region and institution. J AM COLL CARDIOL was the journal with the most published and cocited articles. Cluster analysis showed that clinical trials are the current research hotspot. The areas of risk assessment, prevention strategies, risk factors, and vascular lesions have been popular in recent years. Research on the mechanism of injury in CI-AKI will be the focus of future research, which will be crucial to reduce the clinical incidence of CI-AKI. In summary, this study provides a comprehensive analysis of the development process in the field of CI-AKI and discusses future research directions based on the analysis of objective data from many studies on CI-AKI.

Incorporating intraoperative blood pressure time-series variables to assist in prediction of acute kidney injury after type a acute aortic dissection repair: an interpretable machine learning model

BACKGROUND

Acute kidney injury (AKI) is a common and serious complication after the repair of Type A acute aortic dissection (TA-AAD). However, previous models have failed to account for the impact of blood pressure fluctuations on predictive performance. This study aims to develop machine learning (ML) models combined with intraoperative medicine and blood pressure time-series data to improve the accuracy of early prediction for postoperative AKI risk.

METHODS

Indicators reflecting the duration and depth of hypotension were obtained by analyzing continuous mean arterial pressure (MAP) monitored intraoperatively with multiple thresholds (<65, 60, 55, 50) set in the study. The predictive features were selected by logistic regression and the least absolute shrinkage and selection operator (LASSO), and 4 ML models were built based on the above features. The performance of the models was evaluated by area under receiver operating characteristic curve (AUROC), calibration curve and decision curve analysis (DCA). Shapley additive interpretation (SHAP) was used to explain the prediction models.

RESULTS

Among the indicators reflecting intraoperative hypotension, 65 mmHg showed a statistically superior difference to other thresholds in patients with or without AKI (p < .001). Among 4 models, the extreme gradient boosting (XGBoost) model demonstrated the highest AUROC: 0.800 (95% 0.683-0.917) and sensitivity: 0.717 in the testing set and was verified the best-performing model. The SHAP summary plot indicated that intraoperative urine output, cumulative time of mean arterial pressure lower than 65 mmHg outside cardiopulmonary bypass (OUT_CPB_MAP_65 time), autologous blood transfusion, and smoking were the top 4 features that contributed to the prediction model.

CONCLUSION

With the introduction of intraoperative blood pressure time-series variables, we have developed an interpretable XGBoost model that successfully achieve high accuracy in predicting the risk of AKI after TA-AAD repair, which might aid in the perioperative management of high-risk patients, particularly for intraoperative hemodynamic regulation.

How should we treat acute kidney injury caused by renal congestion?

Decreased kidney function is associated with increased risk of cardiovascular events and mortality, and heart failure (HF) is a wellknown risk factor for renal dysfunction. Acute kidney injury (AKI) in patients with HF often is attributed to prerenal factors, such as renal hypoperfusion and ischemia as a result of decreased cardiac output. Another such factor is reduction of absolute or relative circulating blood volume, with the decrease in renal blood flow leading to renal hypoxia followed by a decrease in the glomerular filtration rate. However, renal congestion is increasingly being recognized as a potential cause of AKI in patients with HF. Increased central venous pressure and renal venous pressure lead to increased renal interstitial hydrostatic pressure and a reduction of the glomerular filtration rate. Both decreased kidney function and renal congestion have been shown to be important prognostic factors of HF, and adequate control of congestion is important for improving kidney function. Loop and thiazide diuretics are recommended as standard therapies to reduce volume overload. However, these agents are associated with worsening renal function even though they are effective for improving congestive symptoms. There is growing interest in tolvaptan, which can improve renal congestion by increasing excretion of free water and decreasing the required dose of loop diuretic, thereby improving kidney function. This review summarizes renal hemodynamics, the pathogenesis of AKI due to renal ischemia and renal congestion, and diagnosis and treatment options for renal congestion.

Active fluid de-resuscitation in critically ill patients with septic shock: A systematic review and meta-analysis

PURPOSE

To evaluate the impact of active fluid de-resuscitation on mortality in critically ill patients with septic shock.

METHODS

A systematic search was performed on PubMed, EmBase, and the Cochrane Library databases. Trials investigating active fluid de-resuscitation and reporting data on mortality in patients with septic shock were eligible. The primary objective was the impact of active de-resuscitation in patients with septic shock on short-term mortality. Secondary outcomes were whether de-resuscitation lead to a fluid separation, and the impact of de-resuscitation on patient-centred outcomes.

RESULTS

Thirteen trials (8,030 patients) were included in the systematic review, whereof 5 randomised-controlled trials (RCTs) were included in the meta-analysis. None of the RCTs showed a reduction in mortality with active de-resuscitation measures (relative risk (RR) 1.12 [95%-CI 0.84 - 1.48]). Fluid separation was achieved by two RCTs. Evidence from non-randomised trials suggests a mortality benefit with de-resuscitation strategies and indicates a trend towards a more negative fluid balance. Patient-centred outcomes were not influenced in the RCTs, and only one non-randomised trial revealed an impact on the duration of mechanical ventilation and renal replacement requirement (RRT).

CONCLUSION

We found no evidence for superiority of active fluid de-resuscitation compared to usual care regarding mortality, fluid balance or patient-centred outcomes in patients with septic shock. Current evidence is limited by the lack of high-quality RCTs in patients with septic shock, the small sample sizes and the heterogeneity of the applied de-resuscitation techniques. In addition, validity of the majority of RCTs is compromised by their inability to achieve fluid separation.

Renal medicine in the intensive care unit: a narrative review

Kidney disease, both acute and chronic, is commonly encountered on the intensive care unit. Due to the role the kidneys play in whole body homeostasis, it follows that their dysfunction has wide-ranging implications and can affect prescribing and therapeutic management. This narrative review discusses the pathophysiology of acute kidney injury and chronic kidney disease, and how this relates to critically unwell patients. We cover several aspects of the management of renal dysfunction on the critical care unit, exploring some of the recurrent themes within the literature, including type and timing of kidney replacement therapy, management of acute kidney injury, as well as discussing how novel biomarkers for acute kidney injury may help to identify patients suffering from acute kidney injury as well as risk stratifying these patients. We discuss how early involvement of specialist nephrology services can improve outcomes in patients with kidney disease as well as offer valuable diagnostic and specialist management advice, particularly for patients with established end stage kidney disease and patients who are already known to nephrology services. We also explore some of the ongoing research questions that need to be answered within this arena.

Caloric restriction reduces the pro-inflammatory eicosanoid 20- hydroxyeicosatetraenoic acid to protect from acute kidney injury

Acute kidney injury is a frequent complication in the clinical setting and associated with significant morbidity and mortality. Preconditioning with short-term caloric restriction is highly protective against kidney injury in rodent ischemia reperfusion injury models. However, the underlying mechanisms are unknown hampering clinical translation. Here, we examined the molecular basis of caloric restriction-mediated protection to elucidate the principles of kidney stress resistance. Analysis of an RNAseq dataset after caloric restriction identified Cyp4a12a, a cytochrome exclusively expressed in male mice, to be strongly downregulated after caloric restriction. Kidney ischemia reperfusion injury robustly induced acute kidney injury in male mice and this damage could be markedly attenuated by pretreatment with caloric restriction. In females, damage was significantly less pronounced and preconditioning with caloric restriction had only little effect. Tissue concentrations of the metabolic product of Cyp4a12a, 20-hydroxyeicosatetraenoic acid (20-HETE), were found to be significantly reduced by caloric restriction. Conversely, intraperitoneal supplementation of 20-HETE in preconditioned males partly abrogated the protective potential of caloric restriction. Interestingly, this effect was accompanied by a partial reversal of caloric restriction-induced changes in protein but not RNA expression pointing towards inflammation, endoplasmic reticulum stress and lipid metabolism. Thus, our findings provide an insight into the mechanisms underlying kidney protection by caloric restriction. Hence, understanding the mediators of preconditioning is an important pre-requisite for moving towards translation to the clinical setting.

Analysis of Risk Factors for Perioperative Acute Kidney Injury and Management Strategies

Acute kidney injury (AKI) is a serious clinical syndrome, and one of the common comorbidities in the perioperative period. AKI can lead to complications in surgical patients and is receiving increasing attention in clinical workup. In recent years, the analysis of perioperative risk factors has become more in-depth and detailed. In this review, the definition, diagnosis, and pathophysiological characteristics of perioperative AKI are reviewed, and the main risk factors for perioperative AKI are analyzed, including advanced age, gender, certain underlying diseases, impaired clinical status such as preoperative creatinine levels, and drugs that may impair renal function such as non-steroidal anti-inflammatory drugs (NASIDs), ACEI/ARB, and some antibiotics. Injectable contrast agents, some anesthetic drugs, specific surgical interventions, anemia, blood transfusions, hyperglycemia, and malnutrition are also highlighted. We also propose potential preventive and curative measures, including the inclusion of renal risk confirmation in the preoperative assessment, minimization of intraoperative renal toxin exposure, intraoperative management and hemodynamic optimization, remote ischemic preadaptation, glycemic control, and nutritional support. Among the management measures, we emphasize the need for careful perioperative clinical examination, timely detection and management of AKI complications, administration of dexmedetomidine for renal protection, and renal replacement therapy. We aim that this review can further increase clinicians' attention to perioperative AKI, early assessment and intervention to try to reduce the risk of AKI.

Chimeric antigen receptor T cell therapy and nephrotoxicity: From diagnosis to treatment strategies

Chimeric antigen receptor T (CAR-T) cell therapy is a breakthrough in cancer treatment. With the widespread use of this therapy, increasing evidence is available that CAR-T cell therapy is associated with acute kidney injury (AKI). Nephrologists need to understand the potential nephrotoxicity arising from CAR-T cell therapy. Determining the cause of AKI is a key factor of clinical management. This review focuses on the clinical use of CAR-T cell therapy and the cause and outcomes of nephrotoxicity with its use. We also provide clinical suggestions for clinicians towards both better diagnosis and management of AKI in those receiving CAR-T cell therapy.

Bundled care in acute kidney injury in critically ill patients, a before-after educational intervention study

BACKGROUND

Acute kidney injury (AKI) often occurs in critically ill patients. AKI is associated with mortality and morbidity. Interventions focusing on the reduction of AKI are suggested by the Kidney Disease: Improving Global Outcomes guideline. We hypothesized that these educational interventions would improve outcome in patients admitted to the Intensive Care Unit (ICU).

METHODS

This was a pragmatic single-centre prospective observational before-after study design in an ICU in a tertiary referral hospital. All consecutive patients admitted to the ICU irrespective their illness were included. A 'Save the Kidney' (STK) bundle was encouraged via an educational intervention targeting health care providers. The educational STK bundle consisted of optimizing the fluid balance (based on urine output, serum lactate levels and/or central venous oxygen saturation), discontinuation of diuretics, maintaining a mean arterial pressure of at least 65 mmHg with the potential use of vasopressors and critical evaluation of the indication and dose of nephrotoxic drugs. The primary outcome was the composite of mortality, renal replacement therapy (RRT), and progression of AKI. Secondary outcomes were the components of the composite outcome the severity of AKI, ICU length of stay and in-hospital mortality.

MAIN RESULTS

The primary outcome occurred in 451 patients (33%) in the STK group versus 375 patients (29%) in the usual care group, relative risk (RR) 1.16, 95% confidence interval (CI) 1.03-1.3, p < 0.001. Secondary outcomes were, ICU mortality in 6.8% versus 5.6%, (RR 1.22, 95% CI 0.90-1.64, p = 0.068), RRT in 1.6% versus 3.6% (RR 0.46, 95% CI 0.28-0.76, p = 0.002), and AKI progression in 28% versus 24% (RR 1.18, 95% CI 1.04-1.35, p = 0.001).

CONCLUSIONS

Providing education to uniformly apply an AKI care bundle, without measurement of the implementation in a non-selected ICU population, targeted at prevention of AKI progression was not beneficial.

Economic and clinical benefits of early identification of acute kidney injury using a urinary biomarker

Purpose: To evaluate the budget impact of adding a diagnostic test of tissue inhibitor of metalloproteinase 2 and insulin-like growth factor binding protein 7 ([TIMP-2]·[IGFBP7]), which identifies patients at risk of moderate-to-severe acute kidney injury (AKI), to the current standard of care (SOC) in a hospital setting.Materials and methods: A budget impact model (2017 USD) was developed from the perspective of a hypothetical US hospital system serving 10,000 inpatients annually. The model estimated the impact of assessing the risk of AKI using SOC vs a combination of SOC and the US Food and Drug Administration-approved assay [TIMP-2]·[IGFBP7] over a 1-year period. Potential cost implications were assessed using estimates for payer mix among patients, diagnostic efficacy, and patient healthcare resource utilization. The model also considered provider adoption rates and the estimated costs of [TIMP-2]·[IGFBP7].Results: Compared to SOC alone, adding [TIMP-2]·[IGFBP7] to SOC was associated with a $1,855 reduction in uncompensated care per patient tested, which, after accounting for the additional costs of the test ($277), resulted in net savings of $1,578 per patient tested. The findings were robust to input parameter variations, as demonstrated by deterministic and probabilistic sensitivity analyses. In the probabilistic sensitivity analyses, net cost savings to the hospital ranged from $50,308-$3,971,514, or $101-$7,943 per tested patient (mean = $1,710; 95% confidence interval = $1,691-$1,729).Conclusions: The introduction of [TIMP-2]·[IGFBP7] as a novel tool in the identification of AKI risk may result in considerable cost savings from a hospital perspective under this model's base-case assumptions. Further prospective studies are needed to confirm these findings in a real-world setting.Key points for decision makersAn economic model was constructed to determine the budget impact of adding a diagnostic test ([TIMP-2]·[IGFBP7]), which identifies patients at risk of moderate-to-severe acute kidney injury, to the current standard of care (SOC) in a hospital setting.According to the present model, the use of [TIMP-2]·[IGFBP7] to identify acute kidney injury risk may reduce costs for hospitals by ∼$1,578 per patient tested.

Association between Blood Potassium Level and Recovery of Postoperative Gastrointestinal Motility during Continuous Renal Replacement Therapy in Patient Undergoing Open Abdominal Surgery

Background

The aim of this study was to identify the blood potassium level beneficial to the postoperative recovery of gastrointestinal motility during continuous renal replacement therapy (CRRT) in patient undergoing open abdominal surgery.

Materials and Methods

538 critically ill patients after open abdominal surgery and receiving CRRT were retrospectively recruited as the study cohort. Demographic and clinical data were recorded along with an evaluation of the postoperative gastrointestinal motility.

Results

Correlation analysis was used to assess the correlation coefficient, and then the variables with correlation coefficient value less than 0.5 were included in the binary logistic regression model. Binary logistic regression model indicated that the postoperative blood potassium level was independently associated with the recovery of gastrointestinal motility (OR=0.109, 95% CI= 0.063 to 0.190, p<0.001). Based on the normal range of blood potassium level, we selected the cut-off point of blood potassium level via Weight of Evidence analysis, which was 4.00 mmol/L. Compared with the patients with insufficient blood potassium levels (plasma potassium concentration < 4.00 mmol/L), those with sufficient blood potassium levels (plasma potassium concentration≥ 4.00 mmol/L) conferred an increase in the rate of 4-day postoperative recovery of gastrointestinal motility (OR= 4.425, 95% CI = 2.933 to 6.667, p<0.001).

Conclusions

Maintaining the blood potassium concentrations at a relatively high level of the normal blood potassium range during CRRT would be beneficial to postoperative recovery of gastrointestinal motility.

Development and validation of quick Acute Kidney Injury-score (q-AKI) to predict acute kidney injury at admission to a multidisciplinary intensive care unit

AKI is associated with increased risk of death, prolonged length of stay and development of de-novo chronic kidney disease. The aim of our study is the development and validation of prediction models to identify the risk of AKI in ICU patients up to 7 days. We retrospectively recruited 692 consecutive patients admitted to the ICU at San Bortolo Hospital (Vicenza, Italy) from 1 June 2016 to 31 March 2017: 455 patients were treated as the derivation group and 237 as the validation group. Candidate variables were selected based on a literature review and expert opinion. Admission eGFR< 90 ml/min /1.73 mq (OR 2.78; 95% CI 1.78–4.35; p<0.001); SOFAcv ≥ 2 (OR 2.23; 95% CI 1.48–3.37; p<0.001); lactate ≥ 2 mmol/L (OR 1.81; 95% CI 1.19–2.74; p = 0.005) and (TIMP-2)•(IGFBP7) ≥ 0.3 (OR 1.65; 95% CI 1.08–2.52; p = 0.019) were significantly associated with AKI. For the q-AKI score, we stratified patients into different AKI Risk score levels: 0–2; 3–4; 5–6; 7–8 and 9–10. In both cohorts, we observed that the proportion of AKI patients was higher in the higher score levels.

Assessment of Regional Perfusion and Organ Function: Less and Non-invasive Techniques

Sufficient organ perfusion essentially depends on preserved macro- and micro-circulation. The last two decades brought substantial progress in the development of less and non-invasive monitoring of macro-hemodynamics. However, several recent studies suggest a frequent incoherence of macro- and micro-circulation. Therefore, this review reports on interactions of macro- and micro-circulation as well as on specific regional and micro-circulation. Regarding global micro-circulation the last two decades brought advances in a more systematic approach of clinical examination including capillary refill time, a graded assessment of mottling of the skin and accurate measurement of body surface temperatures. As a kind of link between macro- and microcirculation, a number of biochemical markers can easily be obtained. Among those are central-venous oxygen saturation (S_cvO₂), plasma lactate and the difference between central-venous and arterial CO₂ (cv-a-pCO₂-gap). These inexpensive markers have become part of clinical routine and guideline recommendations. While their potential to replace parameters of macro-circulation such as cardiac output (CO) is limited, they facilitate the interpretation of the adequacy of CO and other macro-circulatory markers. Furthermore, they give additional hints on micro-circulatory impairment. In addition, a number of more sophisticated technical approaches to quantify and visualize micro-circulation including video-microscopy, laser flowmetry, near-infrared spectroscopy (NIRS), and partial oxygen pressure measurement have been introduced within the last 20 years. These technologies have been extensively used for scientific purposes. Moreover, they have been successfully used for educational purposes and to visualize micro-circulatory disturbances during sepsis and other causes of shock. Despite several studies demonstrating the association of these techniques and parameters with outcome, their practical application still is limited. However, future improvements in automated and “online” diagnosis will help to make these technologies more applicable in clinical routine. This approach is promising with regard to several studies which demonstrated the potential to guide therapy in different types of shock. Finally several organs have specific patterns of circulation related to their special anatomy (liver) or their auto-regulatory capacities (brain, kidney). Therefore, this review also discusses specific issues of monitoring liver, brain, and kidney circulation and function.

Coronary artery bypass graft surgery complications: A review for emergency clinicians

INTRODUCTION

Coronary artery bypass graft (CABG) surgery remains a high-risk procedure, and many patients require emergency department (ED) management for complications after surgery.

OBJECTIVE

This narrative review provides an evidence-based summary of the current data for the emergency medicine evaluation and management of post-CABG surgery complications.

DISCUSSION

While there has been a recent decline in all cardiac revascularization procedures, there remains over 200,000 CABG surgeries performed in the United States annually, with up to 14% of these patients presenting to the ED within 30 days of discharge with post-operative complications. Risk factors for perioperative mortality and morbidity after CABG surgery can be divided into three categories: patient characteristics, clinician characteristics, and postoperative factors. Emergency physicians will be faced with several postoperative complications, including sternal wound infections, pneumonia, thromboembolic phenomena, graft failure, atrial fibrillation, pulmonary hypertension, pericardial effusion, strokes, renal injury, gastrointestinal insults, and hemodynamic instability. Critical patients should be evaluated in the resuscitation bay, and consultation with the primary surgical team is needed, which improves patient outcomes. This review provides several guiding principles for management of acute complications. Understanding these complications and an approach to the management of hemodynamic instability is essential to optimizing patient care.

CONCLUSIONS

Postoperative complications of CABG surgery can result in significant morbidity and mortality. Physicians must rapidly diagnose these conditions while evaluating for other diseases. Early surgical consultation is imperative, as is optimizing the patient's hemodynamics, including preload, heart rate, cardiac rhythm, contractility, and afterload.

Intraoperative mannitol during robotic-assisted-laparoscopic partial nephrectomy

Mannitol is routinely used during partial nephrectomies due to its renoprotective properties. With minimally invasive techniques, the need for mannitol has been questioned. Robotic-assisted laparoscopic partial nephrectomy (RALPN) has been shown to decrease warm ischemia time, which may potentially minimize the benefit of mannitol. To date, no prospective, randomized, controlled trials have investigated the use of mannitol in only robotic procedures. We hypothesize that the intraoperative mannitol use during RALPN provides no statistically significant benefit for post-operative renal function outcomes. We conducted a randomized, controlled, double-blinded, single surgeon, prospective study to assess renal function after RALPN. Patients were randomized into a control group with intravenous normal saline infusion prior to clamping of the vessels or to an experimental group with an infusion of mannitol. Estimated glomerular filtration rate (eGFR) were obtained prior to the surgery as well as post operatively at 24 h, 1 week, and 30 days. Preoperative eGFR showed no statistical differences between the groups and evaluation of median percent change in eGFR after surgery did not indicate a statistical difference between the groups after RALPN. After prospective analysis of the change in post-operative renal function of randomized groups who received 12 g of mannitol following RALPN, we determined that infusion of mannitol does not provide significant improvement of maintenance of renal functions after RALPN. Based on our results, we recommend discontinuing routine use of mannitol during RALPN.

Biomarkers of renal recovery after acute kidney injury

Novel biomarkers can be suitable for early acute kidney injury diagnosis and the prediction of the need for dialysis. It remains unclear whether such biomarkers may also play a role in the prediction of recovery after established acute kidney injury or in aiding the decision of when to stop renal support therapy. PubMed, Web of Science and Google Scholar were searched for studies that reported on the epidemiology of renal recovery after acute kidney injury, the risk factors of recovery versus non-recovery after acute kidney injury, and potential biomarkers of acute kidney injury recovery. The reference lists of these articles and relevant review articles were also reviewed. Final references were selected for inclusion in the review based on their relevance. New biomarkers exhibited a potential role in the early diagnosis of acute kidney injury recovery. Urine HGF, IGFBP-7, TIMP-2 and NGAL may improve our ability to predict the odds and timing of recovery and eventually renal support withdrawal. Acute kidney injury recovery requires more study, and its definition needs to be standardized to allow for better and more powerful research on biomarkers because some of them show potential for the prediction of acute kidney injury recovery.

"Do not do" recommendations of the working groups of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) for the management of critically ill patients

The project "Commitment to Quality of Scientific Societies", promoted since 2013 by the Spanish Ministry of Health, seeks to reduce unnecessary health interventions that have not proven effective, have little or doubtful effectiveness, or are not cost-effective. The objective is to establish the "do not do" recommendations for the management of critically ill patients. A panel of experts from the 13 working groups (WGs) of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) was selected and nominated by virtue of clinical expertise and/or scientific experience to carry out the recommendations. Available scientific literature in the management of adult critically ill patients from 2000 to 2017 was extracted. The clinical evidence was discussed and summarized by the experts in the course of consensus finding of each WG, and was finally approved by the WGs after an extensive internal review process carried out during the first semester of 2017. A total of 65 recommendations were developed, of which 5 corresponded to each of the 13 WGs. These recommendations are based on the opinion of experts and scientific knowledge, and aim to reduce those treatments or procedures that do not add value to the care process; avoid the exposure of critical patients to potential risks; and improve the adequacy of health resources.

A plea for an early ultrasound-clinical integrated approach in patients with acute heart failure. A proactive comment on the ESC Guidelines on Heart Failure 2016

BACKGROUND

The European Association of Cardiology (ESC) Guidelines on the diagnosis and treatment of acute heart failure (AHF) indicate prompt therapy initiation and performance of relevant investigations as paramount. Specifically, echocardiography prior to treatment is advocated only with hemodynamic instability, and the evaluation of clinical signs of peripheral perfusion and congestion is suggested as guidance for early interventions. Given the growing body of evidence on the diagnostic/monitoring capabilities of bedside ultrasound (including focused cardiac ultrasound, comprehensive echocardiography, lung ultrasound), we discuss the potential benefit of an integrated clinical/ultrasound approach at the very early stages of acute heart failure.

METHODS AND RESULTS

We proposed a narrative review of the current evidence on the clinical-ultrasound integrated approach to AHF, with special emphasis on the components of the early diagnostic-therapeutic workup where cardiac, inferior vena cava and lung ultrasound showed high diagnostic accuracy and the capability of substantially changing an exclusively clinically-oriented patient management. A proactive comment to the ESC guidelines is made, suggesting an integration of clinical and biochemical assessment, as defined by guidelines, with combined bedside ultrasound on may help in the definition of AHF pathophysiology and treatment.

CONCLUSION

A multi-organ integrated clinical-ultrasound approach should be advocated as part of the clinical-diagnostic workup at AHF very early phase. Whenever competence and technology available, bedside ultrasound, along with clinical and biochemical assessment, should target AHF profiling, identify the cause of AHF, and subsequently aid disease course and response to treatment monitoring.

Cardiopulmonary Resuscitation in Infants and Children With Cardiac Disease: A Scientific Statement From the American Heart Association

Cardiac arrest occurs at a higher rate in children with heart disease than in healthy children. Pediatric basic life support and advanced life support guidelines focus on delivering high-quality resuscitation in children with normal hearts. The complexity and variability in pediatric heart disease pose unique challenges during resuscitation. A writing group appointed by the American Heart Association reviewed the literature addressing resuscitation in children with heart disease. MEDLINE and Google Scholar databases were searched from 1966 to 2015, cross-referencing pediatric heart disease with pertinent resuscitation search terms. The American College of Cardiology/American Heart Association classification of recommendations and levels of evidence for practice guidelines were used. The recommendations in this statement concur with the critical components of the 2015 American Heart Association pediatric basic life support and pediatric advanced life support guidelines and are meant to serve as a resuscitation supplement. This statement is meant for caregivers of children with heart disease in the prehospital and in-hospital settings. Understanding the anatomy and physiology of the high-risk pediatric cardiac population will promote early recognition and treatment of decompensation to prevent cardiac arrest, increase survival from cardiac arrest by providing high-quality resuscitations, and improve outcomes with postresuscitation care.

Fluid balance concepts in medicine: Principles and practice

The regulation of body fluid balance is a key concern in health and disease and comprises three concepts. The first concept pertains to the relationship between total body water (TBW) and total effective solute and is expressed in terms of the tonicity of the body fluids. Disturbances in tonicity are the main factor responsible for changes in cell volume, which can critically affect brain cell function and survival. Solutes distributed almost exclusively in the extracellular compartment (mainly sodium salts) and in the intracellular compartment (mainly potassium salts) contribute to tonicity, while solutes distributed in TBW have no effect on tonicity. The second body fluid balance concept relates to the regulation and measurement of abnormalities of sodium salt balance and extracellular volume. Estimation of extracellular volume is more complex and error prone than measurement of TBW. A key function of extracellular volume, which is defined as the effective arterial blood volume (EABV), is to ensure adequate perfusion of cells and organs. Other factors, including cardiac output, total and regional capacity of both arteries and veins, Starling forces in the capillaries, and gravity also affect the EABV. Collectively, these factors interact closely with extracellular volume and some of them undergo substantial changes in certain acute and chronic severe illnesses. Their changes result not only in extracellular volume expansion, but in the need for a larger extracellular volume compared with that of healthy individuals. Assessing extracellular volume in severe illness is challenging because the estimates of this volume by commonly used methods are prone to large errors in many illnesses. In addition, the optimal extracellular volume may vary from illness to illness, is only partially based on volume measurements by traditional methods, and has not been determined for each illness. Further research is needed to determine optimal extracellular volume levels in several illnesses. For these reasons, extracellular volume in severe illness merits a separate third concept of body fluid balance.

Hydroxyethyl starch and kidney function: A retrospective study in patients undergoing therapeutic plasma exchange

PURPOSE

Hydroxyethyl starch (HES) and albumin are used as replacement fluids during therapeutic plasma exchange (TPE). HES solutions are no longer recommended in critically ill patients due to its effect on kidneys and coagulation. In this retrospective study, we tried to look at the association between cumulative HES administration and kidney function in patients undergoing TPE.

METHODS

Transfusion medicine department register was scrutinized to identify adult patients who had completed at least 5 cycles of TPE during the period June 2014-May 2015. Patient demographics, indication for TPE, amount of plasma removed, amount of colloid administered, adverse events and vascular access details were collected. Electronic hospital database was scrutinized to retrieve lab parameters, including blood urea and serum creatinine (before and after 5 cycles of TPE) and platelet count. Baseline renal parameters were compared with post TPE values using Wilcoxon signed rank test. A p value <0.05 was kept as significant.

RESULTS

Of the 593 patients who received TPE during the study period, 104 patients fulfilled the inclusion criteria. Forty-five patients out of 104 received TPE in the intensive care unit. All patients received 2500 ml of HES during the study period. Blood urea and serum creatinine values, when compared to baseline, significantly decreased after 5 cycles of TPE (p = 0.004, p = 0.001, respectively).

CONCLUSION

Blood urea and serum creatinine, used as markers of renal function, improved in patients requiring multiple doses of HES solutions during TPE. Further studies using novel renal biomarkers are required to examine whether HES induces any structural damage to kidneys.

Perioperative COX-2 inhibitors may increase the risk of post-operative acute kidney injury

BACKGROUND

In enhanced recovery protocols (ERP), a restrictive fluid regimen is proposed. Patients who undergo major surgery have an increased risk of post-operative acute kidney injury (AKI). This combination may pose difficulties when ERP is used for patients undergoing major surgery. The aim of this study was to evaluate whether patients undergoing pancreatic surgery and treated with a restrictive fluid regimen are at greater risk of post-operative AKI. Furthermore, if there was an increased risk of AKI, we aimed to identify its cause.

METHODS

We reviewed the medical records of patients who underwent pancreatic surgery during 2014 (preERP, n = 58) and 2015 (ERP, n = 65). Fluid balance, the administration of cyclooxygenase-2 inhibitors, creatinine levels and mean arterial pressure were recorded. The Kidney Disease: Improving Global Outcomes criteria were used to define AKI.

RESULTS

The incidence of AKI was higher in the ERP group than in the PreERP group (12.5% vs. 1.8%, respectively, P = 0.035). The increased incidence of AKI could not be explained by differences in comorbidities, age, pre-operative creatinine or perioperative hypotension. Administration of coxibs was higher in the ERP group and was associated with increased incidence of post-operative AKI (P = 0.018). The combination of coxibs and restrictive fluid regimen seems particularly harmful.

CONCLUSION

Pancreatic surgery with a restrictive fluid regimen carries an increased risk of post-operative AKI if patients are also treated with cyclooxygenase-2 inhibitors. It is therefore suggested that in protocols including a restrictive fluid regimen for open pancreatic surgery, the use of cyclooxygenase-2 inhibitors should be avoided.

Prevention of acute kidney injury and protection of renal function in the intensive care unit: update 2017 : Expert opinion of the Working Group on Prevention, AKI section, European Society of Intensive Care Medicine

BACKGROUND

Acute kidney injury (AKI) in the intensive care unit is associated with significant mortality and morbidity.

OBJECTIVES

To determine and update previous recommendations for the prevention of AKI, specifically the role of fluids, diuretics, inotropes, vasopressors/vasodilators, hormonal and nutritional interventions, sedatives, statins, remote ischaemic preconditioning and care bundles.

METHOD

A systematic search of the literature was performed for studies published between 1966 and March 2017 using these potential protective strategies in adult patients at risk of AKI. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, exposure to potentially nephrotoxic drugs and radiocontrast. Clinical endpoints included incidence or grade of AKI, the need for renal replacement therapy and mortality. Studies were graded according to the international GRADE system.

RESULTS

We formulated 12 recommendations, 13 suggestions and seven best practice statements. The few strong recommendations with high-level evidence are mostly against the intervention in question (starches, low-dose dopamine, statins in cardiac surgery). Strong recommendations with lower-level evidence include controlled fluid resuscitation with crystalloids, avoiding fluid overload, titration of norepinephrine to a target MAP of 65-70 mmHg (unless chronic hypertension) and not using diuretics or levosimendan for kidney protection solely.

CONCLUSION

The results of recent randomised controlled trials have allowed the formulation of new recommendations and/or increase the strength of previous recommendations. On the other hand, in many domains the available evidence remains insufficient, resulting from the limited quality of the clinical trials and the poor reporting of kidney outcomes.

Renal recovery after acute kidney injury

Acute kidney injury (AKI) is a frequent complication of critical illness and carries a significant risk of short- and long-term mortality, chronic kidney disease (CKD) and cardiovascular events. The degree of renal recovery from AKI may substantially affect these long-term endpoints. Therefore maximising recovery of renal function should be the goal of any AKI prevention and treatment strategy. Defining renal recovery is far from straightforward due in part to the limitations of the tests available to assess renal function. Here, we discuss common pitfalls in the evaluation of renal recovery and provide suggestions for improved assessment in the future. We review the epidemiology of renal recovery and of the association between AKI and the development of CKD. Finally, we stress the importance of post-discharge follow-up of AKI patients and make suggestions for its incorporation into clinical practice. Summary key points are that risk factors for non-recovery of AKI are age, CKD, comorbidity, higher severity of AKI and acute disease scores. Second, AKI and CKD are mutually related and seem to have a common denominator. Third, despite its limitations full recovery of AKI may best be defined as the absence of AKI criteria, and partial recovery as a fall in AKI stage. Fourth, after an episode of AKI, serial follow-up measurements of serum creatinine and proteinuria are warranted to diagnose renal impairment and prevent further progression. Measures to promote recovery are similar to those preventing renal harm. Specific interventions promoting repair are still experimental.

Acute circulatory failure-chronic liver failure-sequential organ failure assessment score: a novel scoring model for mortality risk prediction in critically ill cirrhotic patients with acute circulatory failure

BACKGROUND AND AIM

Acute circulatory failure (ACF) is associated with high mortality rates in critically ill cirrhotic patients. Only a few accurate scoring models exist specific to critically ill cirrhotic patients with acute circulatory failure (CICCF) for mortality risk assessment. The aim was to develop and evaluate a novel model specific to CICCF.

PATIENTS AND METHODS

This study collected and analyzed the data on CICCF from the Multiparameter Intelligent Monitoring in Intensive Care-III database. The acute circulatory failure-chronic liver failure-sequential organ failure assessment (ACF-CLIF-SOFA) score was derived by Cox's proportional hazards regression. Performance analysis of ACF-CLIF-SOFA against CLIF-SOFA and model for end-stage liver disease systems was completed using area under the receiver operating characteristic curve.

RESULTS

ACF-CLIF-SOFA identified six independent factors: mean arterial pressure [hazard ratio (HR)=0.984, 95% confidence interval (CI): 0.978-0.990, P<0.001], vasopressin (HR=1.548, 95% CI: 1.273-1.883, P<0.001), temperature (HR=0.764, 95% CI: 0.694-0.840, P<0.001), bilirubin (HR=1.031, 95% CI: 1.022-1.041, P<0.001), lactate (HR=1.113, 95% CI: 1.084-1.142, P<0.001), and urine output (HR=0.854, 95% CI: 0.767-0.951, P=0.004). ACF-CLIF-SOFA showed a better predictive performance than CLIF-SOFA and model for end-stage liver disease in terms of predicting mortality (0.769 vs. 0.729 vs. 0.713 at 30 days, 0.757 vs. 0.707 vs. 0.698 at 90 days, 0.733 vs. 0.685 vs. 0.691 at 1 year, respectively, all P<0.05).

CONCLUSION

ACF-CLIF-SOFA, as the first model specific to CICCF, enables a more accurate prediction at 30-day, 90-day, and 1-year follow-up periods than other existing scoring systems.

AKIpredictor, an online prognostic calculator for acute kidney injury in adult critically ill patients: development, validation and comparison to serum neutrophil gelatinase-associated lipocalin

PURPOSE

Early diagnosis of acute kidney injury (AKI) remains a major challenge. We developed and validated AKI prediction models in adult ICU patients and made these models available via an online prognostic calculator. We compared predictive performance against serum neutrophil gelatinase-associated lipocalin (NGAL) levels at ICU admission.

METHODS

Analysis of the large multicenter EPaNIC database. Model development (n = 2123) and validation (n = 2367) were based on clinical information available (1) before and (2) upon ICU admission, (3) after 1 day in ICU and (4) including additional monitoring data from the first 24 h. The primary outcome was a comparison of the predictive performance between models and NGAL for the development of any AKI (AKI-123) and AKI stages 2 or 3 (AKI-23) during the first week of ICU stay.

RESULTS

Validation cohort prevalence was 29% for AKI-123 and 15% for AKI-23. The AKI-123 model before ICU admission included age, baseline serum creatinine, diabetes and type of admission (medical/surgical, emergency/planned) and had an AUC of 0.75 (95% CI 0.75-0.75). The AKI-23 model additionally included height and weight (AUC 0.77 (95% CI 0.77-0.77)). Performance consistently improved with progressive data availability to AUCs of 0.82 (95% CI 0.82-0.82) for AKI-123 and 0.84 (95% CI 0.83-0.84) for AKI-23 after 24 h. NGAL was less discriminant with AUCs of 0.74 (95% CI 0.74-0.74) for AKI-123 and 0.79 (95% CI 0.79-0.79) for AKI-23.

CONCLUSIONS

AKI can be predicted early with models that only use routinely collected clinical information and outperform NGAL measured at ICU admission. The AKI-123 models are available at http://akipredictor.com/ . Trial registration Clinical Trials.gov NCT00512122.

Toll‑like receptor 4 contributes to acute kidney injury after cardiopulmonary resuscitation in mice

Toll-like receptor 4 (TLR4) activation mediates renal injury in regional ischemia and reperfusion (I/R) models generated by clamping renal pedicles. However, it remains unclear whether TLR4 is causal in the kidney injury following global I/R induced by cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). The present study used wild-type (C3H/HeN) and TLR4-mutant (C3H/HeJ) mice to produce the CA/CPR model. CA was induced by injection of cold KCl and left untreated for different time periods. After resuscitation (72 h), the level of blood urea nitrogen (BUN) and serum creatinine (Scr), as well as histological changes in renal tissue were assessed to evaluate the severity of acute kidney injury (AKI). The expression of TLR4, intercellular adhesion molecule-1 (ICAM-1), myeloperoxidase (MPO) and growth-regulated oncogene-β (GRO-β) in kidney tissues was detected. The results demonstrated that the levels of Scr and BUN increased significantly in C3H/HeN and C3H/HeJ mice after CPR. CPR also resulted in increased expression of TLR4, ICAM-1, GRO-β and MPO in a CA-duration dependent manner. However, there was decreased expression of ICAM-1, GRO-β and MPO in C3H/HeJ mice compared with that in C3H/HeN mice. C3H/HeJ mice were resistant to AKI as demonstrated by the minor changes in renal histology and function following CPR. In conclusion, mice suffered from AKI after successful CPR and severe AKI occurred in mice with prolonged CA duration. TLR4 and its downstream signaling events that promote neutrophil infiltration via ICAM-1 and GRO-β may be important in mediating inflammatory responses to renal injury after CPR.

Peri-operative renal dysfunction: prevention and management

Postoperative increases in serum creatinine concentration, by amounts historically viewed as trivial, are associated with increased morbidity and mortality. Acute kidney injury is common, affecting one in five patients admitted with acute medical disease and up to four in five patients admitted to intensive care, of whom one in two have had operations. This review is focused principally on the identification of patients at risk of acute kidney injury and the prevention of injury. In the main, there are no interventions that directly treat the damaged kidney. The management of acute kidney injury is based on correction of dehydration, hypotension, and urinary tract obstruction, stopping nephrotoxic drugs, giving antibiotics for bacterial infection, and commencing renal replacement therapy if necessary.

Predictive value of the RIFLE urine output criteria on contrast-induced nephropathy in critically ill patients

Background

To investigate the predictive value of decreased urine output based on the Risk of renal dysfunction, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal disease (RIFLE) classification on contrast- induced acute kidney injury (CA-AKI) in intensive care (ICU) patients.

Methods

All patients who received contrast media (CM) injection for CT scan or coronary angiography during a 3-year period in a 24 bed medico-surgical ICU were reviewed.

Results

Daily serum creatinine concentrations and diuresis were measured for 3 days after CM injection. We identified 23 cases of CA-AKI in the 149 patients included (15.4 %). Patients who developed CA-AKI were more likely to require renal replacement therapy and had higher ICU mortality rates. At least one RIFLE urine output criteria was observed in 45 patients (30.2 %) and 14 of these 45 patients (31.1 %) developed CA-AKI based on creatinine concentrations. In 30 % of these cases, urine output decreased or didn’t change after the increase in creatinine concentrations. The RIFLE urine output criteria had low sensitivity (39.1 %) and specificity (67.9 %) for prediction of CA-AKI, a low positive predictive value of 50 % and a negative predictive value of 87.2 %. The maximal dose of vasopressors before CM was the only independent predictive factor for CA-AKI.

Conclusions

CA-AKI is a frequent pathology observed in ICU patients and is associated with increased need for renal replacement therapy and increased mortality. The predictive value of RIFLE urine output criteria for the development of CA-AKI based on creatinine concentrations was low, which limits its use for assessing the effects of therapeutic interventions on the development and progression of AKI.

Fenoldopam to prevent acute kidney injury after major surgery-a systematic review and meta-analysis

Background

Acute kidney injury (AKI) after surgery is associated with increased mortality and healthcare costs. Fenoldopam is a selective dopamine-1 receptor agonist with renoprotective properties. We conducted a systematic review and meta-analysis of randomised controlled trials comparing fenoldopam with placebo to prevent AKI after major surgery.

Methods

We searched EMBASE, PubMed, meta-Register of randomised controlled trials and Cochrane CENTRAL databases for trials comparing fenoldopam with placebo in patients undergoing major surgery. The primary outcome was incidence of new AKI. Secondary outcomes were requirement for renal replacement therapy and hospital mortality.

Results

Eighty-three publications were screened; 23 studies underwent full data extraction and scoring. Six trials were suitable for inclusion in the data synthesis (total of 507 subjects undergoing cardiovascular surgery, partial nephrectomy, liver transplant surgery). Five studies were rated at high risk of bias. Data on post-operative incidence of AKI were available in five of the six trials (total of 471 patients) but definitions of AKI varied between studies. Of the 238 patients receiving fenoldopam, 45 (18.9 %) developed AKI compared to 62 (26.6 %) of the 233 patients who received placebo (p = 0.004, I² = 0 %; random-effects model odds ratio 0.46, 95 % confidence interval 0.27–0.79). In patients treated with fenoldopam, there was no difference in renal replacement therapy (n = 478; p = 0.11, I² = 47 %; fixed-effect model odds ratio 0.27, 95 % confidence interval 0.06–1.19) or hospital mortality (p = 0.60, I² = 0 %; fixed-effect model odds ratio 1.0, 95 % confidence interval 0.14–7.37).

Conclusions

In this analysis, peri-operative treatment with fenoldopam was associated with a significant reduction in post-operative AKI but it had no impact on renal replacement therapy or hospital mortality. Equipoise remains for further large trials in this area since the studies were conducted in three types of surgery, the majority of studies were rated at high risk of bias and the criteria for AKI varied between trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1166-4) contains supplementary material, which is available to authorized users.

Dopamine impairs functional integrity of rat hepatocytes through nuclear factor kappa B activity modulation: An in vivo, ex vivo, and in vitro study

Dopamine (DA) is commonly used to maintain the hemodynamic stability of brain-dead donors despite its controversial effects on organ functions. This study aimed at examining the hemodynamic effect of DA in a rat brain-dead model in vivo, alteration of hepatocyte integrity in liver grafts after ex vivo preservation, and changes in cultured clone-9 hepatocytes including cellular viability, cell cycle, apoptotic regulators, and lipopolysaccharide (LPS)-stimulated nuclear factor kappa B (NF-κB) signaling machinery. Although in vivo findings demonstrated enhanced portal venous blood flow and hepatic microcirculatory perfusion after DA infusion, no apparent advantage was noted in preserving hepatocyte integrity ex vivo. In vitro, prolonged exposure to high-dose DA reduced proliferation and induced G1 growth arrest of clone-9 hepatocytes with concomitant decreases in B cell lymphoma 2 (BCL2)/B cell lymphoma 2-associated X protein (BAX) and heat shock protein 70/BAX protein ratios and intracellular NF-κB p65. Moreover, DA pretreatment suppressed LPS-elicited inhibitor of κBα phosphorylation and subsequent NF-κB nuclear translocation, suggesting that DA may down-regulate NF-κB signaling, thereby reducing expression of antiapoptotic regulators, such as BCL2. In conclusion, despite augmentation of hepatic perfusion, DA infusion failed to preserve hepatocyte integrity both in vivo and ex vivo. In vitro findings demonstrated that high-dose DA may hamper the function of NF-κB signaling machinery and eventually undermine functional integrity of hepatocytes in liver grafts.

Emergency general surgery in the geriatric patient

BACKGROUND

Emergency general surgery in the elderly is a particular challenge to the surgeon in charge of their care. The aim was to review contemporary aspects of managing elderly patients needing emergency general surgery and possible alterations to their pathways of care.

METHODS

This was a narrative review based on a PubMed/MEDLINE literature search up until 15 September 2015 for publications relevant to emergency general surgery in the geriatric patient.

RESULTS

The number of patients presenting as an emergency with a general surgical condition increases with age. Up to one-quarter of all emergency admissions to hospital may be for general surgical conditions. Elderly patients are a particular challenge owing to added co-morbidity, use of drugs and risk of poor outcome. Frailty is an important potential risk factor, but difficult to monitor or manage in the emergency setting. Risk scores are not available universally. Outcomes are usually severalfold worse than after elective surgery, in terms of both higher morbidity and increased mortality. A care bundle including early diagnosis, resuscitation and organ system monitoring may benefit the elderly in particular. Communication with the patient and relatives throughout the care pathway is essential, as indications for surgery, level of care and likely outcomes may evolve. Ethical issues should also be addressed at every step on the pathway of care.

CONCLUSION

Emergency general surgery in the geriatric patient needs a tailored approach to improve outcomes and avoid futile care. Although some high-quality studies exist in related fields, the overall evidence base informing perioperative acute care for the elderly remains limited.

Renocardiac syndromes: physiopathology and treatment stratagems

Purpose of review

Bidirectional inter-organ interactions are essential for normal functioning of the human body; however, they may also promote adverse conditions in remote organs. This review provides a narrative summary of the epidemiology, physiopathological mechanisms and clinical management of patients with combined renal and cardiac disease (recently classified as type 3 and 4 cardiorenal syndrome). Findings are also discussed within the context of basic research in animal models with similar comorbidities.

Sources of information

Pertinent published articles were identified by literature search of PubMed, MEDLINE and Google Scholar. Additional data from studies in the author’s laboratory were also consulted.

Findings

The prevalence of renocardiac syndrome throughout the world is increasing in part due to an aging population and to other risk factors including hypertension, diabetes and dyslipidemia. Pathogenesis of this disorder involves multiple bidirectional interactions between the kidneys and heart; however, participation of other organs cannot be excluded. Our own work supports the hypothesis that the uremic milieu, caused by kidney dysfunction, produces major alterations in vasoregulatory control particularly at the level of the microvasculature that results in impaired oxygen delivery and blood perfusion.

Limitations

Recent clinical literature is replete with articles discussing the necessity to clearly define or characterize what constitutes cardiorenal syndrome in order to improve clinical management of affected patients. Patients are treated after onset of symptoms with limited available information regarding etiology. While understanding of mechanisms involved in pathogenesis of inter-organ crosstalk remains a challenging objective, basic research data remains limited partly because of the lack of animal models.

Implications

Preservation of microvascular integrity may be the most critical factor to limit progression of multi-organ disorders including renocardiac syndrome. More fundamental studies are needed to help elucidate physiopathological mechanisms and for development of treatments to improve clinical outcomes.

Short-term Effects of Acute Kidney Injury

Acute kidney injury (AKI) is associated with significant short-term morbidity and mortality, which cannot solely be explained by loss of organ function. Renal replacement therapy allows rapid correction of most acute changes associated with AKI, indicating that additional pathogenetic factors play a major role in AKI. Evidence suggests that reduced renal cytokine clearance as well as increased cytokine production by the acutely injured kidney contribute to a systemic inflammation state, which results in significant effects on other organs. AKI seems to compromise the function of the innate immune system. AKI is an acute systemic disease with serious distant organ effects.

Contrast-associated AKI in the critically ill: relevant or irrelevant?

PURPOSE OF REVIEW

Iodinated contrast media are frequently administered in ICU patients. Recent studies challenge the relevance of contrast media toxicity in ICU patients and relate occurrence of acute kidney injury to baseline characteristics and severity of illness.

RECENT FINDINGS

Various findings in studies with kidney biomarkers indicate the causal relationship between contrast media exposure and kidney damage. Contrast media exposure not only causes direct tubular damage and renal hypoperfusion but also initiates the formation of reactive oxygen species in its turn causing tissue damage. The route of administration determines the incidence of contrast-induced acute kidney injury with a higher incidence when contrast media are administered by intra-arterial route versus intravenous route. The impact of contrast-associated acute kidney injury on hospital length of stay, the need for renal replacement therapy and survival remains a matter of debate because of discrepancies between observational versus case-matched studies and limitations of the individual studies.

SUMMARY

There are diverse pathophysiologic mechanisms explaining the causal relationship between the administration of contrast media and the development of acute kidney injury. Some studies challenge the relevance of contrast media toxicity in ICU patients. However, limitations of the available studies in ICU patients preclude firm conclusions. A precautionary approach in the administration of contrast media is justified.

Effects of fluid administration on renal perfusion in critically ill patients

Introduction

Fluid administration is a first-line therapy for acute kidney injury associated with circulatory failure. Although aimed at increasing renal perfusion in these patients, this intervention may improve systemic hemodynamics without necessarily ameliorating intrarenal flow distribution or urine output. We used Doppler techniques to investigate the effects of fluid administration on intrarenal hemodynamics and the relationship between changes in renal hemodynamics and urine output. We hypothesized that, compared to systemic hemodynamic variables, changes in renal hemodynamics would better predict increase in urine output after fluid therapy.

Methods

We measured systemic hemodynamic variables and performed renal interlobar artery Doppler on both kidneys before and after volume expansion in 49 adult patients with acute circulatory failure. We measured systolic and diastolic velocities and computed the resistivity index (RI). We recorded urine output for 3 h before and after the fluid challenge.

Results

Fluid administration resulted in a small but consistent decrease in RI (from 0.73 ± 0.09 to 0.71 ± 0.09, p < 0.01). There was a concomitant increase in mean arterial pressure (from 75 ± 15 to 80 ± 14 mmHg, p < 0.01), pulse pressure (49 ± 19 to 55 ± 19 mmHg, p < 0.01) and urine output (55 ± 76 to 81 ± 87 ml/hour, p < 0.01). Changes in RI were negatively correlated with changes in urine output and mean arterial pressure but not in pulse pressure. The increase in urine output was predicted by changes in RI but not by changes in systemic hemodynamics.

Conclusions

Changes in renal hemodynamics during a fluid challenge can be observed by Doppler ultrasonography before urine output increases. Moreover, these changes are better predictors of an increase in urine output than are mean arterial pressure and pulse pressure.