Continuous renal replacement therapy in critically ill patients

Acute kidney injury outcomes in covid-19 patients: systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is a frequent complication of coronavirus-19 disease (COVID-19). Therefore, we decided to perform a systematic review and meta-analysis with data from the literature to relate the development of COVID-19 associated-AKI with comorbidities, medications, and the impact of mechanical ventilation.

METHODS

We performed a systematic review using the Newcastle-Ottawa scale and a meta-analysis using the R program. Relevant studies were searched in the PubMed, Medline, and SciELO electronic databases. Search filters were used to include reports after 2020 and cohort studies.

RESULTS

In total, 1166 articles were identified and 55 English-written articles were included based on the risk of bias. Of all COVID-19-hospitalized patients presenting with AKI (n = 18029) classified as Kidney Disease Improving Global Outcomes stage 1 to 3, approximately 18% required mechanical ventilation and 39.2 % died. Around 11.3% of the patients required kidney replacement therapy (KRT) and of these, 1093 died and 321 required continuous KRT. Death is more frequent in individuals with AKI [OR 6.03, 95%CI: 5.73-6.74; p<0.01]. Finally, mechanical ventilation is an aggravating factor in the clinical conditions studied [OR 11.01, 95%CI: 10.29-11.77; p<0.01].

CONCLUSION

Current literature indicates AKI as an important complication in COVID-19. In this context, we observed that comorbidities, such as chronic kidney disease and heart failure, were more related to the development of AKI. In addition, mechanical ventilation was seen as an aggravating factor in this scenario.

Desfechos de lesão renal aguda em pacientes com covid-19: revisão sistemática e metanálise

Resumo Antecedentes: Lesão renal aguda (LRA) é uma complicação frequente da doença do coronavírus-19 (COVID-19). Desta forma, decidimos realizar uma revisão sistemática e uma metanálise com dados da literatura para relacionar o desenvolvimento de LRA associada à COVID-19 com comorbidades, medicamentos e o impacto da ventilação mecânica. Métodos: Realizamos uma revisão sistemática usando a escala de Newcastle-Ottawa e uma metanálise utilizando o programa R. Estudos relevantes foram pesquisados nos bancos de dados eletrônicos PubMed, Medline e SciELO. Foram utilizados filtros de pesquisa para incluir relatos após 2020 e estudos de coorte. Resultados: No total, foram identificados 1166 artigos, e foram incluídos 55 artigos escritos em língua inglesa com base no risco de viés. De todos os pacientes hospitalizados por COVID-19 apresentando LRA (n = 18029) classificados como Kidney Disease Improving Global Outcomes estágios 1 a 3, aproximadamente 18% necessitaram de ventilação mecânica e 39,2% foram a óbito. Cerca de 11,3% dos pacientes necessitaram de terapia renal substitutiva (TRS) e destes, 1093 foram a óbito e 321 necessitaram de TRS contínua. O óbito é mais frequente em indivíduos com LRA [OR 6,03; IC95%: 5,73-6,74; p<0,01]. Por fim, a ventilação mecânica é um fator agravante nas condições clínicas estudadas [OR 11,01; IC95%: 10,29-11,77; p<0,01]. Conclusão: A literatura atual indica a LRA como uma complicação importante na COVID-19. Neste contexto, observamos que comorbidades, como doença renal crônica e insuficiência cardíaca, estiveram mais relacionadas ao desenvolvimento de LRA. Além disso, a ventilação mecânica foi vista como um fator agravante neste cenário.

Effect of Early Continuous Veno-Venous Haemofiltration in Severe Acute Pancreatitis for the Prevention of Local Pancreatic Complications

Objective

To compare the conventional treatment and continuous veno-venous haemofiltration (CVVH) in severe acute pancreatitis (SAP) for the prevention of pseudocyst and walled-off necrosis. Patients and Methods. Forty-two patients were divided into two treatment groups: conventional treatment group contained 24 patients and CVVH had 18. Conventional treatment group patients were treated symptomatically and according to the causes. CVVH group patients were treated symptomatically, and CVVH was done within 2 hours of admission.

Results

In both groups, there was a decrease in amylase, lipase, CRP, IL-6, IL-10, TNF-alpha, Ranson score, Balthazar score, and APACHE-II score after 72 hours, but the decrease was significantly greater in CVVH patients. There were no any local pancreatic complications in CVVH patients, but 1 patient had an acute peripancreatic fluid collection, 2 patients had pseudocyst, and 2 patients had walled-off necrosis (WON), and a mortality one was seen in the conventional treatment group.

Conclusion

The present study shows that early CVVH may be able to prevent the formation of pseudocyst and win in SAP patients.

Analysis of the dynamic relationship between immune profiles and the clinical features of patients with COVID-19

Background

The novel coronavirus disease (COVID-19) has been declared a global pandemic, with the cumulative number of confirmed cases and deaths exceeding 150 million and 3 million, respectively. Here, we examined the dynamic changes in the immune and clinical features of patients with COVID-19.

Methods

Clinical data of 98 patients with confirmed COVID-19 diagnosis were acquired from electronic medical records and curated. The data were analyzed based on the stage of the admission, deterioration, and convalescence, which included age, sex, severity, disease stages, biochemical indicators, immune cells, inflammatory cytokines, and immunoglobulins. Additionally, temporal changes in the immune response in patients undergoing continuous renal replacement therapy (CRRT) were also examined.

Results

Compared to mild stage patients, severe stage patients with COVID-19 exhibited a significant reduction in lymphocyte [23.10 (17.58-33.55) vs. 4.80 (2.95-6.50), P<0.001], monocyte [8.65 (7.28-10.00) vs. 3.45 (2.53-4.58), P<0.001], and NK cell levels [244.00 (150.50-335.00) vs. 59.00 (40.00-101.00), P<0.001] but showed elevated levels of neutrophils [64.90 (56.30-73.70) vs. 90.95 (87.60-93.68), P<0.001], inflammatory cytokines [Interleukin-10, 3.05 (1.37-3.86) vs. 5.94 (3.84-8.35), P=0.001; and tumor necrosis factor-α, 11.50 (6.55-26.45) vs. 12.96 (12.22-36.80), P=0.029], which improved during convalescence. Besides, the number of immune cells-T lymphocytes, B lymphocytes, helper T cells, suppressor T cells, NK cells, and monocytes, except neutrophils-slowly increased in critically ill patients receiving CRRT from 0 to 3 weeks.

Conclusions

Our results indicate that the surveillance of immune cells may contribute to monitoring COVID-19 disease progression, and CRRT is a potential therapeutic strategy to regulate the immune balance in critically ill patients.

Safety and Feasibility of Physical Rehabilitation and Active Mobilization in Patients Requiring Continuous Renal Replacement Therapy: A Systematic Review

OBJECTIVES

To evaluate the safety and feasibility of physical rehabilitation and active mobilization in patients requiring continuous renal replacement therapy in the ICU.

DATA SOURCES

Medline, CINAHL, PubMed, Pedro, and Cochrane Library were used to extract articles focused on physical activity and mobility in this population.

STUDY SELECTION

Research articles were included in this review if 1) included adult patients greater than or equal to 18 years old requiring continuous renal replacement therapy located in the ICU; 2) described physical rehabilitation, active mobilization, or physical activity deliverables; 3) reported data on patient safety and/or feasibility. The primary outcome was safety, defined as number of adverse events per total number of sessions.

DATA EXTRACTION

Five-hundred seven articles were evaluated based on title and abstract with reviewers selecting 46 to assess by full text. Fifteen observational studies were included for final analysis with seven studies focused solely on physical activity in patients requiring continuous renal replacement therapy.

DATA SYNTHESIS

Four-hundred thirty-seven adult ICU patients requiring continuous renal replacement therapy participated in some form of physical rehabilitation, physical activity, or active mobilization. Two major adverse events (hypotension event requiring vasopressor and continuous renal replacement therapy tube disconnection, pooled occurrence rate 0.24%) and 13 minor adverse events (pooled occurrence rate 1.55%) were reported during a total of 840 individual mobility or activity sessions. Intervention fidelity was limited by a low prevalence of higher mobility with only 15.5% of incidences occurring at or above level 5 of ICU Mobility Scale (transfer to chair, marching in place or ambulation away from bed, 122/715 reports). Feasibility in the provision of these interventions and/or continuous renal replacement therapy-specific deliverables was inconsistently reported.

CONCLUSIONS

Early rehabilitation and mobilization, specifically activity in and near the hospital bed, appears safe and mostly feasible in ICU patients requiring continuous renal replacement therapy. A cautious interpretation of these data is necessary due to limited aggregate quality of included studies, heterogeneous reporting, and overall low achieved levels of mobility potentially precluding the occurrence or detection of adverse events.

Multicenter study on the consciousness-regaining effect of a newly developed artificial liver support system in acute liver failure: An on-line continuous hemodiafiltration system

AIM

Acute liver failure (ALF) patients with coma need to be revived not only for spontaneous recovery but also as a bridge to liver transplantation. We developed a new high-volume plasma purification system using an on-line continuous hemodiafiltration (CHDF) system, and evaluated its safety and efficacy in a multicenter study.

METHODS

A single arm interventional study using the new apparatus was undertaken in the six major liver centers in Japan. The primary end-point was the proportion of patients who regained consciousness within 10 days, which was compared with a historical control (47%). Nine ALF patients were enrolled and treated with the new machine. One patient was excluded because of the need for artificial respiration support according to the established protocol.

RESULTS

Seven of eight (87.5%) patients regained consciousness during the on-line CHDF session, with five of those seven waking within 4 days. After waking, one patient spontaneously recovered, three received liver transplantation, two died of liver failure, and one died of another disease. The plasma ammonia levels significantly decreased after the start of on-line CHDF from 182.5 ± 64.8 μg/dL (mean ± SD) on day 0 to 87.0 ± 38.9 μg/dL on the last day of the session (P < 0.001). Similarly, the plasma glutamine level also significantly decreased from 2069 ± 1234 μmol/L to 628 ± 193 μmol/L. Although seven severe adverse events occurred during on-line-CHDF, no causal relationship with liver support was recognized.

CONCLUSIONS

The newly developed on-line CHDF system showed high efficacy for regain of consciousness and excellent therapeutic safety for managing ALF.

Continuous Kidney Replacement Therapy of the Future: Innovations in Information Technology, Data Analytics, and Quality Assurance Systems

Continuous kidney replacement therapy is commonly used in the critically ill population. Despite the recent development in continuous kidney replacement therapy technology and clinical informatics, many aspects of continuous kidney replacement therapy delivery are still not fully standardized, and quality assurance programs for the provision of continuous kidney replacement therapy are not fully developed. This is in part explained by practice variations, suboptimal integration between machine and clinical data, and the lack of validated continuous kidney replacement therapy quality indicators that are feasible for measurement and monitoring. The further development and sustainable implementation of quality assurance systems that support continuous kidney replacement therapy delivery rely on the collaborative work of the critical care nephrology community and the continuous evolution of clinical informatics. In this article, we describe the present status of information technology and quality assurance systems for continuous kidney replacement therapy delivery and provide a framework for technology development and implementation which is in the pipeline of enhanced continuous kidney replacement therapy delivery.

Posthepatectomy liver failure

Liver surgery is one of the most complex surgical interventions with high risk and potential for complications. Posthepatectomy liver failure (PHLF) is a serious complication of liver surgery that occurs in about 10% of patients undergoing major liver surgery. It is the main source of morbidity and mortality. Appropriate surgical techniques and intensive care management are important in preventing PHLF. Early start of the liver support systems is very important for the PHLF patient to recover, survive, or be ready for a liver transplant. Nonbiological and biological liver support systems should be used in PHLF to prepare for treatment or organ transplantation. The definition of the state, underlying pathophysiology and treatment strategies will be reviewed here.

Galápagosization of sepsis management in Japan: a nationwide survey of current practices

Aim

Sepsis treatment has been standardized in many countries worldwide. However, treatment of sepsis in Japan has developed independently, and how Japanese physicians actually treat sepsis patients nationwide remains uninvestigated. The aim of this study was to clarify the current practice for septic patients in Japan and how it differs from standard care throughout the world.

Methods

This study was designed as a prospective, cross‐sectional, self‐reported questionnaire‐ and Web‐based electronic survey in Japan. The survey was undertaken to assess respondents’ clinical practices and preferences regarding treatment strategies, sepsis assessment, and management in the setting of critical illness. An exploratory factor analysis and a hierarchical cluster analysis were carried out to identify the treatments distinctive to Japan, called “Galápagos therapies”.

Results

The final analysis included 295 respondents. According to the factor analysis, we defined anticoagulant therapy for disseminated intravascular coagulation, antimediator renal replacement therapy, and others as Galápagos therapies. These Galápagos therapies were undertaken by approximately two‐thirds of the Japanese physicians who responded. We classified Japanese physicians according to three patterns of clinical practice carried out for sepsis: (i) those who do not perform Galápagos therapies but do perform worldwide standardized care, (ii) those who perform Galápagos therapies on top of worldwide standardized care, (iii) those who do not perform worldwide standardized care.

Conclusion

On the basis of a nationwide questionnaire‐based survey in Japan, we clarified distinctive sepsis treatments performed in Japan, such as antimediator renal replacement therapy and treatment for sepsis‐induced disseminated intravascular coagulation.

Diagnostics, Risk Factors, Treatment and Outcomes of Acute Kidney Injury in a New Paradigm

Acute kidney injury (AKI) is a common clinical condition among patients admitted in the hospitals. The condition is associated with both increased short-term and long-term mortality. With the development of a standardized definition for AKI and the acknowledgment of the impact of AKI on patient outcomes, there has been increased recognition of AKI. Two advances from past decades, the usage of computer decision support and the discovery of AKI biomarkers, have the ability to advance the diagnostic method to and further management of AKI. The increasingly widespread use of electronic health records across hospitals has substantially increased the amount of data available to investigators and has shown promise in advancing AKI research. In addition, progress in the finding and validation of different forms of biomarkers of AKI within diversified clinical environments and has provided information and insight on testing, etiology and further prognosis of AKI, leading to future of precision and personalized approach to AKI management. In this this article, we discussed the changing paradigms in AKI: from mechanisms to diagnostics, risk factors, and management of AKI.

The therapeutic effect of high-volume hemofiltration on sepsis: a systematic review and meta-analysis

Background

Sepsis remains the leading cause of death in the intensive care unit (ICU), despite the treatment of sepsis has progressed. As a mode in continuous renal replacement therapy (CRRT), continuous veno-venous hemofiltration (CVVH) has been widely used in the treatment of sepsis. Whether high ultrafiltrate volume in CVVH is beneficial for sepsis survival remains controversial. We performed a systematic review and meta-analysis to evaluate the treatment effect of high-volume hemofiltration (HVHF) on sepsis.

Methods

A systematic search was conducted on the Medline, Embase, and Cochrane library to June 21, 2019, the keywords included “sepsis” “continuous blood purification” “continuous renal replacement therapy” “continuous veno-venous hemofiltration” and “continuous veno-venous hemodiafiltration”. Summery statistic in this review was risk ratio (RR) and was performed by RevMan 5.2.

Results

Five randomized controlled trials (RCT) were included which contained 241 participants. Mortality related endpoints and other observations (length of stay, organ function evaluation, effect on hemodynamics, cytokine clearance and respiratory function) were used to assess the treatment effect of HVHF in sepsis. Three trials reported 28-day mortality, one of three trails also reported 60- and 90-day mortality; one trail did not specify the type of mortality; the fifth article reported hospital mortality. The pooled risk ratio for three trails of 28-day mortality was 0.96 (0.67, 1.38). Three trails reported length of stay related data. Four trails reported organ failure related scores. All trails reported the effect of HVHF on hemodynamics. Three trails reported cytokine clearance. Only two trails reported respiratory function related indicators. After analysis, the risk of bias in all trails was low.

Conclusions

The meta-analysis results suggested that treatment programs contained HVHF did not change the outcomes of patients with sepsis. So far, related studies on the use of HVHF in critically ill patients with sepsis or septic shock is rare. Researchers should consider additional large multicenter randomized controlled trials.

Hemoperfusion plus continuous veno-venous hemofiltration in the treatment of patients with multiple organ failure after wasp stings

PURPOSE

This study aimed to evaluate the clinical effects of hemoperfusion plus continuous veno-venous hemofiltration in the treatment of patients with multiple organ failure after wasp stings and investigate its impacts on cytokines.

METHODS

A total of 12 patients with multiple organ failure after wasp stings admitted to Xijing Hospital were included in the present study between January 2017 and January 2019. All patients received hemoperfusion plus continuous veno-venous hemofiltration treatment in addition to conventional treatment after admission. Procedure of treatment was conducted as the following: hemoperfusion (2 h/day) and followed by continuous veno-venous hemofiltration (22 h/day) for at least 5 days. Patients' clinical features, serum laboratory tests, and hemodynamic variables were monitored. The blood samples were taken to measure the changes of plasma cytokines.

RESULTS

All 12 patients survived in the observation period. After hemoperfusion plus continuous veno-venous hemofiltration treatment, there were significant improvements in indicators of liver function, renal function, state of consciousness, and mediators in blood circulation, including alanine transaminase, aspartate transaminase, creatine kinase, blood urea nitrogen, serum creatinine, myoglobin, C-reactive protein, and so on. In these patients, acid-base metabolism returned to normal levels; Acute Physiology and Chronic Health Evaluation II score, Simplified Acute Physiology Score II score, and Sequential Organ Failure Assessment score lowered markedly. Furthermore, the plasma levels of interleukin 1β, interleukin 4, interleukin 6, interleukin 8, and interleukin 10 in these patients were significantly decreased; no significant change was shown in the level of tumor necrosis factor α.

CONCLUSION

Our results revealed that hemoperfusion plus continuous veno-venous hemofiltration was effective in the management of patients with multiple organ failure after wasp sting via the non-specific removal of the wasp venom and inflammatory cytokines.

[Renal replacement therapy for acute kidney injury in the intensive care unit]

Renal replacement therapy for acute kidney injury has been used for more than 60 years. Except when life-threatening metabolic complications such as severe hyperkalaemia are present, renal replacement therapy initiation criteria are the subject of intense debate. Significant progress has been made with the publication of the AKIKI multicenter trial, which showed that a delayed renal replacement therapy initiation strategy (in the absence of life-threatening metabolic complications) was not associated with a difference in mortality compared to an early renal replacement therapy initiation strategy. In addition, this delayed strategy obviated the need for renal replacement therapy in almost 50% of cases was associated with a more rapid renal function recovery and with a lower incidence of catheter-bloodstream related infections. Research on renal replacement therapy modalities (continuous vs. intermittent renal replacement therapy, citrate vs. heparin anticoagulation, jugular vs. femoral catheterization) did not show any obvious superiority of one modality over another. Thus, the choice depends mainly on local considerations (patient recruitment, availability of modalities, staff experience). The criteria for renal replacement therapy discontinuation are still unclear due to difficulties in assessing renal function recovery. Urine output remains the main criteria in the decision to wean from renal replacement therapy. Pending the confirmation of AKIKI trial by similar studies in progress, it seems reasonable to choose a delayed renal replacement therapy initiation strategy under watchful surveillance in case of severe acute kidney injury in the absence of life-threatening metabolic complications.

Prevention of hypophosphatemia during continuous renal replacement therapy-An overlooked problem

Hypophosphatemia is a common and potentially serious complication occurring during continuous renal replacement therapy (CRRT). Phosphate supplementation is required in the vast majority of patients undergoing CRRT, particularly beyond the first 48 hours. Supplementation can be provided either as a standalone oral or parenteral treatment or as an additive to CRRT solutions. Each approach has advantages and disadvantages, and clinicians must weigh the individual factors most relevant in their practice setting. Currently there are no consensus protocols for phosphate replacement in CRRT, and many centers replete phosphate in response to hypophosphatemia as opposed to pre-emptively. Repletion protocols have also been challenged in recent years by shortages in injectable phosphate solutions. More recently a commercially available phosphate-containing CRRT solution was approved in the United States, but there has been limited clinical experience with this product. In this review, we present recommendations for phosphate repletion in CRRT to prevent hypophosphatemia, and describe our experience using phosphate-containing CRRT solutions.

Effect of Coupled Plasma Filtration Adsorption on Endothelial Cell Function in Patients with Multiple Organ Dysfunction Syndrome

Objective

The purpose of our study was to investigate the effect of coupled plasma filtration adsorption (CPFA) on endothelial cell (EC) function in patients with multiple organ dysfunction syndrome (MODS).

Methods

Besides routine therapy, the 24 MODS patients underwent both CPFA and high volume hemofiltration (HVHF), scheduled randomly at intervals of 12 hours. Patient serum from 0, 5, and 10 hours of therapy was collected to measure soluble E-selectin (sE-selectin) and soluble thrombomodulin (sTM) by the ELISA method. Human umbilical vein endothelial cells (HUVEC) were incubated for 24 hours with the patient serum and the supernatant liquid was gathered to detect sTM and sE-selectin. The proliferation function of the ECs was detected by methyl thiazolyl tetrazolium (MTT) method.

Results

1. The serum levels of sE-selectin and sTM were significantly higher in MODS patients than in controls; serum sE-selectin and sTM decreased remarkably after a single circulation in CPFA (p<0. 05) but not in HVHF (p>0. 05); the level of sE-selectin and sTM in systemic circulation had no change during CPFA or HVHF (p>0.05); 2. sTM in supernatant liquid incubated with serum from 5 hours of CPFA and 10 hours of HVHF decreased remarkably (p<0.05), while sE-selectin decreased significantly (p<0. 05) from 10 hours of CPFA, but there was no change from 5 hours and 10 hours of HVHF (p>0. 05); 3. when incubated with serum taken from the device pre- or post-CPFA, the optical density (OD) value of the latter was higher. The OD value increased gradually when incubated with serum from 0, 5, and 10 hours of CPFA (p<0.05), but changed little from HVHF.

Conclusions

CPFA can eliminate sE-selectin and sTM and improve the secretion function of ECs. CPFA was somewhat better and earlier than HVHF, while to a certain degree it can weaken the inhibitory effect of serum on the proliferation function of ECs.

Endothelial Dysfunction in Patients with Severe Acute Pancreatitis: Improved by Continuous Blood Purification Therapy

Objectives.

Endothelium dysfunction is one of the critical pathophysiologic disorders in patients with severe acute pancreatitis (SAP). To investigate the effect of continuous blood purification (CBP) on endothelial function, we conducted a prospective study of 20 patients with SAP, 9 of whom had evidence of sepsis.

Methods.

All patients underwent CVVH for 72 h. Soluble E-selectin (sE-selectin), soluble thrombomodulin, permeability of the endothelial monolayer, and endothelial intracellular calcium ([Ca2+]i) levels were used as the markers for the assessment of endothelial function and the effect of CBP therapy in patients with SAP. Blood samples were taken from the patients at 0, 2, 12, 24, 48, and 72 h during CVVH therapy. sE-selectin and thrombomoduiln were measured by ELISA. The endothelial permeability and activation were evaluated using cultured endothelial monolayer and intracellular Ca2+ concentration.

Results.

The results showed that during CVVH treatment, the hemodynamics and mean arterial pressure (MAP) were stable. The Acute Physiology and Chronic Health Evaluation (APACHE) II score was improved significantly after CVVH. Endothelial dysfunction was evident in patients with SAP as compared to normal controls. Patients with SAP had increased levels of sE-selectin, endothelial permeability and intracellular [Ca2+]i, which was higher in patients with sepsis than in those without sepsis. The level of thrombomodulin showed a tendency to increase; however, these changes were not significant between SAP patients and controls. After CBP treatment, sE-selectin levels substantially decreased in all patients. CBP treatment also significantly diminished the endothelial permeability and decreased the intracellular [Ca2+] concentration.

Conclusions.

These data demonstrate that endothelial dysfunction is present in patients with SAP and the degree of endothelial damage may be correlated with the disease severity. CBP therapy can not only improve the general conditions, as measured by the APACHE II score, but also effectively improve endothelial dysfunction.

Subgroup analysis of continuous renal replacement therapy in severely burned patients

Continuous renal replacement therapy (CRRT) is administered to critically ill patients with renal injuries as renal replacement or renal support. We aimed to identify predictors of mortality among burn patients receiving CRRT, and to investigate clinical differences according to acute kidney injury (AKI) status. This retrospective observational study evaluated 216 Korean burn patients who received CRRT at a burn intensive care unit. Patients were categorized by AKI status. Data were collected regarding arterial pH, laboratory results, ratio of arterial oxygen partial pressure to fractional inspired oxygen (PF ratio), and urine production. Among surviving patients, CRRT duration and the sequential organ failure assessment score were 6.5 days and 4.7 in the non-AKI group and 23.4 days and 7.4 in the AKI group, respectively (p = 0.003 and p = 0.008). On logistic regression analyses, mortality was significantly associated with a pH of <7.2 (p = 0.004), potassium levels of >5.0 mEg/L (p = 0.045), creatinine levels of >2.0 mg/dL (p = 0.011), lactate levels of >2 mmol/L (p<0.001), a PF ratio of <200 (p = 0.042), and a platelet count of <100,000/μL (p<0.001). In the AKI group, poor outcomes were associated with a pH of <7.2, potassium levels of <5.0 mEg/L, lactate levels of >2 mmol/L, and a platelet count of <100,000/μL, while good outcomes were associated with creatinine levels of >2 mg/dL. In the non-AKI group, poor outcomes were associated with lactate levels of >1.5 mmol/L, a PF ratio of <200, and a platelet count of <100,000/μL, while good outcomes were associated with creatinine levels of >1.2 mg/dL. Duration of the CRRT application and the requirement for either renal replacement or renal support at the initiation of CRRT application are important considerations depending on its application.

Effects of Early Continuous Venovenous Hemofiltration on E-Selectin, Hemodynamic Stability, and Ventilatory Function in Patients with Septic-Shock-Induced Acute Respiratory Distress Syndrome

Objective. To investigate the effects of 72-hour early-initiated continuous venovenous hemofiltration (ECVVH) treatment in patients with septic-shock-induced acute respiratory distress syndrome (ARDS) (not acute kidney injury, AKI) with regard to serum E-selectin and measurements of lung function and hemodynamic stability. Methods. This prospective nonblinded single institutional randomized study involved 51 patients who were randomly assigned to receive or not receive ECVVH, an ECVVH group (n = 24) and a non-ECVVH group (n = 27). Besides standard therapies, patients in ECVVH group underwent CVVH for 72 h. Results. At 0 and 24 h after initiation of treatment, arterial partial pressure of oxygen/fraction of inspired oxygen (PaO₂/FiO₂) ratio, extravascular lung water index (EVLWI), and E-selectin level were not significantly different between groups (all P > 0.05). Compared to non-ECVVH group, PaO₂/FiO₂ is significantly higher and EVLWI and E-selectin level are significantly lower in ECVVH group (all P < 0.05) at 48 h and 72 h after initiation of treatment. The lengths of mechanical ventilation and stay in intensive care unit (ICU) were shorter in ECVVH group (all P < 0.05), but there was no difference in 28-day mortality between two groups. Conclusions. In patients with septic-shock-induced ARDS (not AKI), treatment with ECVVH in addition to standard therapies improves endothelial function, lung function, and hemodynamic stability and reduces the lengths of mechanical ventilation and stay in ICU.

Continuous Infusion Vancomycin Through the Addition of Vancomycin to the Continuous Renal Replacement Therapy Solution in the PICU: A Case Series

OBJECTIVES

To describe our experience with achieving therapeutic serum vancomycin concentrations in pediatric continuous renal replacement therapy by using continuous infusion vancomycin by mixing vancomycin into the continuous renal replacement therapy solution.

DESIGN

Retrospective chart review.

SETTING

A 189-bed, freestanding children's tertiary care teaching hospital in Philadelphia, PA.

PATIENTS

Pediatric patients receiving continuous renal replacement therapy from April 1, 2009, through December 31, 2014.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were a total of 21 patients who received continuous renal replacement therapy during the study period. Of these, 11 (52.3%) received vancomycin in the continuous renal replacement therapy solution. The median (range) concentration of vancomycin added to the continuous renal replacement therapy solution was 25 mg/L (18-35 mg/L). The mean vancomycin plateau level was 22.8 ± 3.3 mg/L. All patients achieved a serum vancomycin plateau level that was greater than 15 mg/L. There were no adverse events related to the addition of vancomycin to the continuous renal replacement therapy solution.

CONCLUSIONS

The addition of vancomycin to the continuous renal replacement therapy solution(s) is an effective modality that is used for delivering vancomycin continuous infusion and for ensuring therapeutic vancomycin serum plateau levels in the setting of pediatric continuous renal replacement therapy. Further studies are required to evaluate whether this delivery method can lead to improved patient outcomes.

Outcomes associated with the use of renal replacement therapy in children receiving extracorporeal membrane oxygenation after heart surgery: a multi-institutional analysis

BACKGROUND

The primary objective of this investigation was to study the association between renal replacement therapy (RRT) and outcomes in children receiving extracorporeal membrane oxygenation (ECMO).

METHODS

Patients aged ≤18 years receiving ECMO before or after a pediatric heart operation at a Pediatric Health Information System (PHIS)-participating hospital (2004-2013) were included. The associations between RRT and study outcomes were computed using multivariate logistic regression analysis.

RESULTS

A total of 3,502 patients from 43 hospitals qualified for inclusion. Of these, 484 (14 %) patients received RRT at some point during their hospital stay. After adjusting for patient and center characteristics, the odds of mortality were significantly higher in the RRT group (OR: 1.86, 95 % CI: 1.46- 2.37, p < 0.0001). However, there were considerable reductions in adjusted odds of mortality, compared to unadjusted odds of mortality. In adjusted models, length of ECMO was longer by 0.81 days (95 % CI: 0.13- 1.49, p = 0.02) in patients receiving RRT.

CONCLUSIONS

We demonstrated worsening outcomes in children receiving ECMO with RRT compared to children receiving ECMO without RRT. Although the results could reflect confounding by severity of illness, they provide a rationale for prospective testing of use of RRT in critically ill children receiving ECMO with heart surgery.

The possible impact of the German DRGs reimbursement system on end-of-life decision making in a surgical intensive care unit

BACKGROUND

More than 70 % of critically ill patients die in intensive care units (ICUs) after treatment is reduced. End-of-life decision making in the ICU is a grey area that varies in practice, and there are potential economic consequences of over- and under-treatment. The aim of this study was to describe the end-of-life decisions of critically ill patients in a surgical ICU in Germany and to identify how financial incentives may influence decision making.

METHODS

Data on the admission diagnosis, end-of-life decision making and cause of death were obtained for 69 critically ill patients who died in the ICU (Hospital of Bayreuth, Germany) in 2009. A cost-revenue analysis was conducted on the 46 patients who did not die within 3 days of ICU admission. Because we lacked real data on costs, our analysis was based on the average cost for each diagnosis-related group (DRG) from the Institute for the Hospital Remuneration System (InEK). Hospital revenues based on the DRG were considered. Subsequently, we compared the estimated financial impact of earlier and later decisions to withdraw or withhold futile therapy.

RESULTS

In this study, we found that end-of-life decision making was poorly documented. Only 11 % of patients had a valid power of attorney and advanced directives, and therapy with presumed consent was performed in 43 % of all cases. From long-stay patients, therapy was withdrawn for 37 % of patients and withheld from 26 % of patients, and 37 % of the patients died receiving maximal therapy. Almost 72 % of DRG-related reimbursements were dependent on ventilation hours. The average total cost estimate (according to InEK) for the 46 long-stay patients was 1,201,000 <euro>. The revenues without additional remuneration were 1,358,000 <euro>, and the total estimated profit was approximately 157,000 <euro>. Only 10 cases were assumed to be non-profitable. In cases where the decision to withdraw or withhold therapy could have occurred 3 days earlier, the estimated profit shrank to 72,000 <euro> (46 % of estimated ICU profit). In situations where the decision to withdraw or withhold therapy from patients could have occurred 3 days later, the hypothetical profit rose to 217,000 <euro> (138 % of estimated ICU profit).

CONCLUSION

There are still few patients with clear self-determination, and almost half of therapies are performed only according to presumed consent. The strong nonlinear dependence of DRG revenues on ventilation hours could influence ethical decision making of medical professionals. The decision-making process and appropriate therapy in the ICU setting need to be defined more clearly and better documented, focusing on the benefits to the patient while respecting patient consent.

The interface between monitoring and physiology at the bedside

Hemodynamic instability as a clinical state represents either a perfusion failure with clinical manifestations of circulatory shock or heart failure or 1 or more out-of-threshold hemodynamic monitoring values, which may not necessarily be pathologic. Different types of causes of circulatory shock require different types of treatment modalities, making these distinctions important. Diagnostic approaches or therapies based on data derived from hemodynamic monitoring assume that specific patterns of derangements reflect specific disease processes, which respond to appropriate interventions. Hemodynamic monitoring at the bedside improves patient outcomes when used to make treatment decisions at the right time for patients experiencing hemodynamic instability.

Prognostic factors in continuous hemofiltration therapy for patients with cardiorenal syndrome

AIMS

The aims of this study were to investigate the efficacy and identify the prognostic factors of continuous hemofiltration in patients with cardiorenal syndrome (CRS) and, finally, to optimally select patients who could benefit more from this therapy.

METHODS

A total of 59 patients with CRS type 1 or type 2 treated with continuous hemofiltration were enrolled. We collected their clinical data and divided them into 2 groups according to their survival or death during hospitalization to conduct a retrospective analysis on factors affecting mortality.

RESULTS

The following items were significantly different between the survival (n = 30) and death (n = 29) groups: serum creatinine, serum total bilirubin, direct bilirubin, white blood cells, hemoglobin, hematocrit, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, systolic blood pressure and mean arterial pressure before hemofiltration, and average dehydration volume during the hemofiltration process. Leukocytosis was a risk factor for death (OR 1.242, 95% CI 1.242-1.480), and elevated sCr was not a key negative factor in the prognosis of CRS (OR 0.994, 95% CI 0.989-1.000).

CONCLUSIONS

Cardiac function before hemofiltration and the amount of dehydration during the hemofiltration process both affected the prognosis. Infection and fluid overload condition at the beginning of hemofiltration were independently associated with mortality during hospitalization.

Purinergic signaling and blood vessels in health and disease

Purinergic signaling plays important roles in control of vascular tone and remodeling. There is dual control of vascular tone by ATP released as a cotransmitter with noradrenaline from perivascular sympathetic nerves to cause vasoconstriction via P2X1 receptors, whereas ATP released from endothelial cells in response to changes in blood flow (producing shear stress) or hypoxia acts on P2X and P2Y receptors on endothelial cells to produce nitric oxide and endothelium-derived hyperpolarizing factor, which dilates vessels. ATP is also released from sensory-motor nerves during antidromic reflex activity to produce relaxation of some blood vessels. In this review, we stress the differences in neural and endothelial factors in purinergic control of different blood vessels. The long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides in promoting migration and proliferation of both vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis and vessel remodeling during restenosis after angioplasty are described. The pathophysiology of blood vessels and therapeutic potential of purinergic agents in diseases, including hypertension, atherosclerosis, ischemia, thrombosis and stroke, diabetes, and migraine, is discussed.

Cardio-renal syndromes: a systematic approach for consensus definition and classification

The "Cardio-Renal Syndrome" (CRS) is a disorder of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other. The general definition has been expanded to five subtypes reflecting the primacy of organ dysfunction and the time-frame of the syndrome: CRS type I: acute worsening of heart function (AHF-ACS) leading to kidney injury and/or dysfunction. CRS type II: chronic abnormalities in heart function (CHF-CHD) leading to kidney injury or dysfunction. CRS type III: acute worsening of kidney function (AKI) leading to heart injury and/or dysfunction. CRS type IV: chronic kidney disease (CKD) leading to heart injury, disease and/or dysfunction. CRS type V: systemic conditions leading to simultaneous injury and/or dysfunction of heart and kidney. Different pathophysiological mechanisms are involved in the combined dysfunction of heart and kidney in these five types of the syndrome.

Extracorporeal renal replacement therapy and blood purification in critical care

OBJECTIVE

To review indications methods of renal replacement therapies (RRT) and practical considerations for the creation of a RRT program.

DATA SOURCES

Current human and veterinary literature review with a focus on advanced renal physiology and clinical experience in RRT and acute/chronic kidney diseases.

DATA SYNTHESIS

Renal replacement therapies encompass intermittent hemodialysis, continuous renal replacement therapy as well as some "hybrid" techniques. Each method of RRT has practical and theoretical advantages but currently there is no evidence that one technique is superior to the other.

CONCLUSIONS

RRT is a valuable therapeutic tool for treatment of acute kidney injury and chronic kidney disease. The implementation of an RRT program needs to take into consideration multiple parameters beyond the choice of an RRT platform.

Renal replacement therapy in critically ill patients receiving extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a lifesaving procedure used in neonates, children, and adults with severe, reversible, cardiopulmonary failure. On the basis of single-center studies, the incidence of AKI occurs in 70%-85% of ECMO patients. Those with AKI and those who require renal replacement therapy (RRT) are at high risk for mortality, independent of potentially confounding variables. Fluid overload is common in ECMO patients, and is one of the main indications for RRT. RRT to maintain fluid balance and metabolic control is common in some but not all centers. RRT on ECMO can be performed via an in-line hemofilter or by incorporating a standard continuous renal replacement machine into the ECMO circuit. Both of these methods require specific technical considerations to provide safe and effective RRT. This review summarizes available epidemiologic data and how they apply to our understanding of AKI pathophysiology during ECMO, identifies indications for RRT while on ECMO, reviews technical elements for RRT application in the setting of ECMO, and finally identifies specific research-focused questions that need to be addressed to improve outcomes in this at-risk population.

Treatment of compartment syndrome of the thigh associated with acute renal failure after the Wenchuan earthquake

Compartment syndrome of the thigh is a rare emergency often treated operatively. The purpose of this study was to evaluate the effects of nonoperative treatment for compartment syndrome of the thigh associated with acute renal failure after the 2008 Wenchuan earthquake. Nonoperative treatment, which primarily involves continuous renal replacement therapy, was performed in 6 patients (3 men and 3 women) who presented with compartment syndrome of the thigh associated with acute renal failure. The mean mangled extremity severity score (MESS) and laboratory data regarding renal function were analyzed before and after treatment, and the clinical outcome was evaluated at 17-month follow-up. Laboratory data regarding renal function showed improvements. All 6 patients survived with the affected lower limbs intact after nonoperative treatment. Follow-up revealed active knee range of motion and increased muscle strength, as well as a recovery of sensation. A positive linear correlation was found between MESS and the time required to achieve a reduction in swelling, as well as the time required for the recovery of sensation and knee range of motion (r>0.8; P<.05). Satisfactory clinical outcomes were obtained in patients with compartment syndrome of the thigh associated with acute renal failure.Urine alkalization, electrolyte and water balance, and continuous renal replacement therapy have played an important role in saving lives and extremities. Nonoperative treatment should be considered in the treatment of compartment syndrome of the thigh associated with acute renal failure.

Epidemiology, pathophysiology, clinical characteristics and management of childhood cardiorenal syndrome

Cardiorenal syndrome (CRS) is a new term recently introduced to describe the acute or chronic comorbid state of the heart and kidney that has been long known and frequently managed in very sick individuals. The tight and delicate coordination of physiological functions among organ systems in the human body makes dysfunction in one to lead to malfunction of one or more other organ systems. CRS is a universal very common morbidity in the critically ill, with a high mortality rate that has received very little research attention in children. Simultaneous management of heart and renal failures in CRS is quite challenging; the therapeutic choice made for one organ must not jeopardize the other. This paper reviews the epidemiology, pathophysiology, clinical characteristics and management of acute and chronic CRS in children.

Cardio-renal syndromes: from foggy bottoms to sunny hills

"Cardio-renal syndromes" (CRS) are disorders of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other. The current definition has been expanded into five subtypes whose etymology reflects the primary and secondary pathology, the time-frame and simultaneous cardiac and renal co-dysfunction secondary to systemic disease: CRS type I: acute worsening of heart function (AHF-ACS) leading to kidney injury and/or dysfunction. CRS type II: chronic abnormalities in heart function (CHF-CHD) leading to kidney injury or dysfunction. CRS type III: acute worsening of kidney function (AKI) leading to heart injury and/or dysfunction. CRS type IV: chronic kidney disease (CKD) leading to heart injury, disease and/or dysfunction. CRS type V: systemic conditions leading to simultaneous injury and/or dysfunction of heart and kidney. These different subtypes may have a different pathophysiological mechanism and they may represent separate entities in terms of prevention and therapy.

Recovery of renal function and survival after continuous renal replacement therapy during extracorporeal membrane oxygenation

OBJECTIVE

To assess the outcome of pediatric patients supported by concomitant extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT).

DESIGN, SETTING, AND PATIENTS

Acute kidney injury is associated with mortality in ECMO patients. CRRT in patients on ECMO provides an efficient and potentially beneficial method of acute kidney injury management. Concern that concomitant CRRT use increases the risk of developing anuria and chronic renal failure limits its use in some centers. We hypothesized that development of chronic renal failure is rare with concurrent ECMO and CRRT. We evaluated the outcomes of 154 ECMO/CRRT patients cared for over 10 yrs at a referral pediatric medical center.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 68 (44%) ECMO/CRRT survivors, 45 were assigned a pediatric risk, injury, failure, loss and end-stage (referred to as "pRIFLE") score at CRRT initiation. Seventeen (38%) patients met the criteria for Risk, 15 (33%) for Injury, and 10 (22%) for Failure. Two Failure patients later met End stage criteria. Of all survivors, 18 (26%) required ongoing renal replacement therapy (15 required continuous veno-venous hemofiltration, two required peritoneal dialysis, and one patient required intermittent hemodialysis) post ECMO discontinuation. Renal recovery occurred in 65 (96%) of 68 patients before discharge. One neonatal patient had sepsis-induced renal injury on transfer, but had normal creatinine 1 month later. Two pediatric patients with vasculitis and primary renal disease at presentation (both meeting Failure criteria) developed end-stage renal disease. One received peritoneal dialysis and subsequent renal transplant. The other has diminished function without need for renal replacement therapy.

CONCLUSION

In the absence of primary renal disease, chronic renal failure did not occur after concurrent use of CRRT with ECMO. Concern for precipitating chronic renal failure by using CRRT during ECMO is not substantiated by this large single-center experience. Consistent with previous reports, mortality is higher in patients receiving concomitant CRRT and ECMO compared with those receiving ECMO alone. Mortality is similar to patients requiring CRRT who are not on ECMO. Additional studies are warranted to determine the optimal role of CRRT use in ECMO patients.

Continuous renal replacement therapy in dogs and cats

Continuous renal replacement therapy (CRRT) is a relatively new extracorporeal blood purification modality that is rapidly gaining acceptance for the treatment of acute kidney injury in cats and dogs. The author has used CRRT for the treatment of leptospirosis, tumor lysis syndrome, heatstroke, pre- and postsurgical support of ureteral obstructions, as well as aminoglycoside and melamine toxicities. As the name implies, CRRT is a slow gradual process, and once treatment begins, patients continue therapy until their renal function returns, they are transitioned to intermittent hemodialysis (IHD), or they are euthanized. Unlike IHD, which is a primarily diffusive therapy, CRRT uses diffusion as well as convection. Because of its efficient use of fluids, CRRT units use prepackaged fluids, eliminating the need for costly water purification systems that are needed for IHD.

Norepinephrine and hospital mortality in critically ill patients undergoing continuous renal replacement therapy

High-dose vasopressor use is associated with increasing mortality in patients with septic shock. We conducted this study to determine if the high-dose of vasopressor used before the initiation of continuous renal replacement therapy (CRRT) is associated with increasing mortality in critically ill patients. We retrospectively reviewed all patients who underwent CRRT in the medical intensive care unit of China Medical University Hospital between 2003 and 2007. The association between mortality and highest vasopressors (dopamine and norepinephrine [NE]) dose used were analyzed using Kaplan-Meier analysis and multivariate Cox regression. A total of 279 patients (170 men and 109 women) treated with CRRT in medical intensive care were reviewed and 237 (84.9%) died. In Kaplan-Meier analysis with log-rank test, dopamine dose of ≥20 µg/kg/min and NE dose of ≥0.3 µg/kg/min were significantly linked to mortality (P = 0.007 and <0.001). In multivariate Cox proportional hazards regression, NE dose of ≥0.3 µg/kg/min, Acute Physiology and Chronic Health Evaluation II score, and low platelet count were independently linked to mortality. The hazard ratios and 95% confidence interval (CI) were 1.771 (95% CI: 1.247-2.516, P = 0.001), 1.035 (95% CI: 1.012-1.058, P = 0.003), and 0.997 (95% CI: 0.996-0.999, P = 0.003), respectively. Critically ill patients treated with very high dose of NE before the initiation of CRRT have a very high mortality rate regardless of the acute kidney injury stage.

Continuous renal replacement therapies: a brief primer for the neurointensivist

Continuous renal replacement therapy (CRRT) is a renal replacement modality that is often used in the ICU setting, including the neuro-ICU. This form of renal replacement therapy has been used classically for acute renal failure in patients with hemodynamic compromise, but is gaining acceptance as a method to control vascular and extra-vascular volume and mediate cytokines in non-renal diseases. Although these uses are briefly discussed, this review concentrates on the different forms of continuous renal replacement, mainly focusing on the technology of convective versus diffusive modalities and briefly on filter technology. There is also discussion on the various anticoagulation regimes used in CRRT including data on performing CRRT without anticoagulation. This review is not meant to be a discussion on the pros and cons of CRRT versus intermittent dialysis, but rather a primer on the technology of CRRT and how this therapy may affect general care of the ICU patient.

Evaluation of the effects of pulse high-volume hemofiltration in patients with severe sepsis: a preliminary study

OBJECTIVES

The aim of this study was to evaluate the effects of pulse high-volume hemofiltration (PHVHF) in patients with severe sepsis.

METHODS

Twenty-two patients with severe sepsis admitted to XiJing hospital between January 2009 and January 2010 were included in the present study. Patients were randomly divided into the control group (conventional treatment) and the PHVHF group. Patients in the PHVHF group received 72 h of PHVHF treatment in addition to conventional treatment after admission. PHVHF was conducted as follows: HVHF 85 ml/kg per hour for 6 h followed by continuous venovenous hemofiltration 35 ml/kg per hour for 18 h with an AN69 membrane. The hemofilter was replaced every 24 h and PHVHF was performed with 250 to 300 ml/min blood flow rate. The blood samples were taken to measure the changes of plasma cytokines (TNF-α, IL-1, IL-4, IL-6 and IL-10).

RESULTS

With 72 h of PHVHF treatment, there was an improvement in clinical features and hemodynamics variables in PHVHF-treated patients. All plasma cytokines after PHVHF treatment were significantly lower than those at the start of PHVHF treatment (p<0.05). In contrast, there was no significant change in control patients.

CONCLUSIONS

Our findings suggest that PHVHF is a feasible adjuvant modality in the treatment of patients with severe sepsis. With the application of PHVHF treatment, plasma cytokines are effectively removed. Considering the lower cost and better feasibility than continuous high-volume hemofiltration (CHVF), PHVHF shows promising prospects for the future.

Renal replacement therapy is an independent risk factor for mortality in critically ill patients with acute kidney injury

INTRODUCTION

Outcome studies in patients with acute kidney injury (AKI) have focused on differences between modalities of renal replacement therapy (RRT). The outcome of conservative treatment, however, has never been compared with RRT.

METHODS

Nine Belgian intensive care units (ICUs) included all adult patients consecutively admitted with serum creatinine >2 mg/dl. Included treatment options were conservative treatment and intermittent or continuous RRT. Disease severity was determined using the Stuivenberg Hospital Acute Renal Failure (SHARF) score. Outcome parameters studied were mortality, hospital length of stay and renal recovery at hospital discharge.

RESULTS

Out of 1,303 included patients, 650 required RRT (58% intermittent, 42% continuous RRT). Overall results showed a higher mortality (43% versus 58%) as well as a longer ICU and hospital stay in RRT patients compared to conservative treatment. Using the SHARF score for adjustment of disease severity, an increased risk of death for RRT compared to conservative treatment of RR = 1.75 (95% CI: 1.4 to 2.3) was found. Additional correction for other severity parameters (Acute Physiology And Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA)), age, type of AKI and clinical conditions confirmed the higher mortality in the RRT group.

CONCLUSIONS

The SHARF study showed that the higher mortality expected in AKI patients receiving RRT versus conservative treatment can not only be explained by a higher disease severity in the RRT group, even after multiple corrections. A more critical approach to the need for RRT in AKI patients seems to be warranted.

Cardiorenal syndromes

PURPOSE OF REVIEW

The purpose of the present review is to identify the mechanisms involved in the syndrome related to combined heart-kidney dysfunction.

RECENT FINDINGS

The bidirectionality of the syndrome and the various time frames involved in the different clinical pictures have induced to generate a new definition of the cardiorenal syndrome, focusing on five specific subtypes (acute cardiorenal syndrome, type 1; chronic cardiorenal syndrome, type 2; acute renocardiac syndrome, type 3; chronic renocardiac syndrome, type 4; and secondary cardiorenal syndrome, type 5).

SUMMARY

The new definition allows to characterize the various clinical scenarios and to identify patients with different subtypes in which the primary disorder and the sequelae are clearly described. Biomarkers for early diagnosis of heart and kidney dysfunction may further contribute to a clearer definition of the disorder. The new classification will allow to test diagnostic tools and prevention strategies as well as therapeutic measures that in the past might not have been applied properly due to the lack of a consistent classification of the syndrome.

Mechanisms of the cardiorenal syndromes

The kidney and heart have essential roles in maintaining blood volume homeostasis and in the regulation of systemic blood pressure. Acute or chronic dysfunction in either the heart or kidneys can induce dysfunction in the other organ, resulting in the so-called cardiorenal syndromes, which are classified into five different types. Abrupt worsening of cardiac function predisposes an individual to acute kidney injury from renal hypoperfusion or renal congestion. Progressive, sometimes permanent, chronic kidney impairment can result from chronic renal hypoperfusion or congestion. Heart failure is common in patients with acute kidney injury. Chronic kidney disease predisposes individuals to atherosclerotic, arteriosclerotic and cardiomyopathic disease. Finally, both cardiac and renal disease can also occur secondary to systemic conditions, such as diabetes or autoimmune disease. This Review examines the mechanisms presiding over the first four types of cardiorenal syndromes. These mechanisms provide a template that accounts for the heart-kidney interactions that occur in patients whose concomitant cardiac and renal conditions result from a third cause.

Continuous Renal Replacement Therapy (CRRT) or Intermittent Hemodialysis (IHD)—What Is the Procedure of Choice in Critically Ill Patients?

Although at present there is no prospective randomized study which could show significantly better survival of patients on continuous procedures, the majority of intensivists advocate this technique of renal function replacement due to generally accepted opinion that it has less effect on circulation of already hemodynamically unstable patients. In our prospective randomized study with 104 patients, we also did not observe any difference in 28 days survival, in total survival, as well as in circulatory instability between two treatment modalities. Even in subgroup of 80 patients with sepsis and septic shock there were no difference in survival. Sepsis was the underlying disorder in 52 and septic shock in 28 patients out of 104 patients analyzed in this study. Our prospective randomized study did not show a statistically significant difference between the two methods of renal replacement therapy. Survival rates were not affected and neither was the occurrence of hemodynamic instability. We believe that both methods are complementary; IHD for faster elimination of electrolytes and waste products elimination, CRRT for regulation of higher calories requirements and for hemodynamically unstable patients. The expectations that one method is superior to the other in the term of better survival have not been corroborated by the current data available in the literature. The choice of the method should be individualized. ARF, which is an integral part of MOF, is a problem frequently encountered in critically ill patient treated in the ICU, but outcome of these patients depends closely on the control of basic event. Evaluation of each of the supportive procedures is therefore hindered by the fact that the underlying disease has the crucial effect on survival and the type of supportive procedure less so.