Recent evolution of renal replacement therapy in the critically ill patient

Nanobody-functionalized conduit with built-in static mixer for specific elimination of cytokines in hemoperfusion

Removing excessively produced cytokines is of paramount significance in blood purification therapy for hypercytokinemia-associated diseases. In this study, we devised a conduit that is modified with nanobodies (Nb) and incorporates static mixers (Nb-SMC) to eliminate surplus cytokines from the bloodstream. The low-pressure-drop (LPD) static mixer, with each unit featuring two 90°-crossed blades, was strategically arranged in a tessellated pattern on the inner wall of the conduit to induce turbulent mixing effects during the flow of blood. This arrangement enhances mass transfer and molecular diffusion, thereby assisting in the identification and elimination of cytokines. By utilizing computational fluid dynamics (CFD) studies, the Nb-SMC was rationally designed and prepared, ensuring an optimal interval between two mixer units (H/G = 2.5). The resulting Nb-SMC exhibited a remarkable selective clearance of IL-17A, reaching up to 85 %. Additionally, the process of Nb immobilization could be adjusted to achieve the simultaneous removal of multiple cytokines from the bloodstream. Notably, our Nb-SMC displayed good blood compatibility without potential adverse effects on the composition of human blood. As the sole documented static mixer-integrated conduit capable of selectively eliminating cytokines at their physiological concentrations, it holds promise in the clinical potential for hypercytokinemia in high-risk patients. STATEMENT OF SIGNIFICANCE: High-efficient cytokines removal in critical care still remains a challenge. The conduit technique we proposed here is a brand-new strategy for cytokines removal in blood purification therapy. On the one hand, nanobody endows the conduit with specific recognition of cytokine, on the other hand, the build-in static mixer enhances the diffusion of antigenic cytokine to the ligand. The combination of these two has jointly achieved the efficient and specific removal of cytokine. This innovative material is the only reported artificial biomaterial capable of selectively eliminating multiple cytokines under conditions close to clinical practice. It has the potential to improve outcomes for patients with hypercytokinemia and reduce the risk of adverse events associated with current treatment modalities.

Continuous renal replacement therapy is a safe and effective modality for the initial management of dogs with acute kidney injury

OBJECTIVE

To describe the management of dogs with acute kidney injury (AKI) by continuous renal replacement therapy (CRRT), and to investigate the relationship between a prescribed CRRT dose, the hourly urea reduction ratio (URR), and the overall efficacy.

ANIMALS

45 client-owned dogs diagnosed with severe AKI, receiving 48 CRRT treatments at a veterinary teaching hospital.

PROCEDURES

Retrospective study. Search of medical records of dogs with AKI managed by CRRT.

RESULTS

Median serum urea and creatinine at CRRT initiation were 252 mg/dL [Inter quartile range (IQR), 148 mg/dL; range, 64 to 603 mg/dL] and 9.0 mg/dL (IQR, 7 mg/dL; range, 4.3 to 42.2 mg/dL), respectively. Median treatment duration was 21 hours (IQR, 8.8 hours; range, 3 to 32 hours). Systemic heparinization and regional citrate anticoagulation were used in 24 treatments each (50%). The prescribed median CRRT dose for the entire treatment was 1 mL/kg/min (IQR, 0.4 mL/kg/min; range, 0.3 to 2.5 mL/kg/min). The median hourly URR was 4% (IQR, 1%; range, 2% to 12%), overall URR was 76% (IQR, 30%; range, 11% to 92%) and median Kt/V was 2.34 (IQR, 1.9; range, 0.24 to 7.02). The CRRT dose was increased gradually from 0.9 mL/kg/min to 1.4 mL/kg/min (P < .001) and the hourly URR decreased from 6.5% to 5.5% (P = .05). The main complication was clotting of the extra-corporeal circuit, occurring in 6/48 treatments (13%). Twenty-four dogs (53%) survived to discharge.

CLINICAL RELEVANCE

CRRT is safe when the prescription is based on the current veterinary guidelines for gradual urea reduction. Treatment efficacy can be maximized by gradually increasing the dose according to the actual URR.

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.

Hemofiltration in Patients with Severe Acute Pancreatitis (Review)

Questions regarding the application of extracorporeal detoxification to patients with severe acute pancreatitis have been considered. Hemodialysis, the historically first method of extracorporeal detoxification for such patients, has been also described in the review. Appropriateness of using renal replacement therapy methods and among them continued renal replacement therapy has been shown. Hemofiltration and hemodiafiltration technologies are described in detail including different modes of their application and the possibility of using various types of filters. Available data on hemofiltration for patients with severe acute pancreatitis have been analyzed. Great attention is paid to the unsolved aspects of hemofiltration in severe acute pancreatitis such as determining renal and extrarenal indices; time of starting hemofiltration; selection of volume replacement modes and a buffer system; procedure duration; anticoagulation measures, defining criteria to assess the adequacy of hemofiltration, state severity, and organ dysfunction degree. Further multicenter investigations are necessary to be able to assess the efficacy of the hemofiltration procedures on the basis of the thoroughly worked out and pathogenically grounded protocol using adequate control methods taking into consideration endogenic intoxication phases and intensity of the multiple organ failure syndrome.

A multi-center cross-sectional study on blood purification among adult patients in intensive care unit in China: a study protocol

Background

Blood purification (BP) is one of the most important rescue measures for patients with critical illness in the intensive care unit (ICU), especially for those with acute kidney injury. The purpose of this nationwide survey was to reveal the real world of current BP practice in different ICUs all over China. This study was designed to be a multi-center cross-sectional study.

Methods

All adult patients (over 18 years of age), who were admitted to ICU and required BP in 35 sub-centers across China were included during 30-day survey period in 2018. Demographic characteristics and clinical data were recorded including the timing of treatment initiation, indications, modality, relative contraindication, establishment of vascular access, selection of filter/membrane, settings, anti-coagulation, executive department, complication, intake, and output.

Discussion

This nationwide survey may contribute to reveal the real world of current BP practice in different ICUs all over China.

Trial registration

Chinese Clinical Trial Registry, ChiCTR-EOC-17013119; http://www.chictr.org.cn/showproj.aspx?proj=22487.

Volume Management by Renal Replacement Therapy in Acute Kidney Injury

Management of fluid balance is one of the basic but vital tasks in the care of critically ill patients. Hypovolemia results in a decrease in cardiac output and tissue perfusion and may lead to progressive multiple organ dysfunction, including the development of acute renal injury (AKI). However, in an effort to reverse pre-renal oliguria, it is not uncommon for patients with established oliguric acute renal failure, particularly when associated with sepsis, to receive excessive fluid resuscitation, leading to fluid overload. In patients with established oliguria, renal replacement therapy may be required to treat hypervolemia. Safe prescription of fluid loss during RRT requires intimate knowledge of the patient's underlying condition, understanding of the process of ultrafiltration and close monitoring of the patient's cardiovascular response to fluid removal. To preserve tissue perfusion in patients with AKI, it is important that RRT be prescribed in a way that optimizes fluid balance by removing fluid without compromising the effective circulating fluid volume. In patients who are clinically fluid overloaded, it is equally important that the amount of fluid removed be as exact as possible. Fluid balance errors can occur as a result of inappropriate prescription, operator error or machine error. Some CRRT machines have potential for significant fluid errors if alarms can be overridden. Threshold values for fluid balance error have been developed which can be used to predict the severity of harm. It is important that RRT education programs emphasize the risk associated with fluid balance errors and with overriding machine alarms.

Extracorporeal renal replacement therapies in the treatment of sepsis: where are we?

Acute kidney injury (AKI) is common among the critically ill, affecting approximately 40% of patients. Sepsis is the cause of AKI in almost 50% of cases of intensive care patients, however, any evidence-based treatment for sepsis-associated AKI is lacking. Furthermore, the underlying pathophysiology of septic AKI is inadequately understood given the disparity between severe functional changes and limited tubular injury. What is clear is that within this complex interplay leading to septic AKI, the inflammatory response plays a pivotal role and hence modulation of this response may translate to improved outcomes. We outline the use of extracorporeal therapies in the treatment of sepsis and septic AKI. We consider the classic aspects of extracorporeal renal replacement therapy including indications, timing, and delivered dose. The various techniques that currently are used to try and achieve immune homeostasis also are outlined. As well as discussing the evidence accumulated to date, we also suggest possibilities for the future treatment of our patients.

Associations between Intensity of RRT, Inflammatory Mediators, and Outcomes

BACKGROUND AND OBJECTIVES

Critically ill patients requiring RRT have higher circulating plasma concentrations of inflammatory and apoptosis markers that are associated with subsequent RRT dependence and death. Whether intensive dosing of RRT is associated with changes in specific mediators is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A multicenter, prospective, cohort study of 817 critically ill patients receiving RRT ancillary to the Veterans Affairs/National Institutes of Health Acute Renal Failure Trial Network study was conducted between November 2003 and July 2007. Plasma inflammatory (IL-6, IL-8, IL-10, IL-18, and macrophage migration inhibitory factor) and apoptosis (TNF receptor-I [TNFR-I], TNFR-II, and death receptor-5) biomarkers on days 1 and 8 were examined after initiation of intensive RRT. Whether intensive RRT, given day 1 biomarkers, is associated with RRT independence and lower mortality at day 60 was also examined.

RESULTS

Overall, no differences were found in day 8 biomarker concentrations between intensive and less-intensive RRT groups. When adjusted for day 1 biomarkers and clinical variables, intensive RRT was not associated with renal recovery (adjusted odds ratio [OR], 0.80; 95% confidence interval, 0.56 to 1.14) or mortality (adjusted OR, 1.15; 95% confidence interval, 0.81 to 1.64). Use of intensive RRT, however, was associated with lower day 8 concentrations when day 1 plasma IL-6, macrophage migration inhibitory factor, and TNFR-I concentrations were high (interaction P value for all markers, <0.01). In contrast, day 8 marker concentrations were higher when day 1 levels were low (P<0.01). Elevated biomarker concentrations on day 8 among 476 participants were associated with lower renal recovery (adjusted OR range, 0.19-0.87) and higher mortality (adjusted OR range, 1.26-3.18).

CONCLUSIONS

Among critically ill patients receiving RRT, intensive dosing of RRT has variable association with biomarker concentration and no association with renal recovery and mortality. However, elevated concentrations of inflammatory and apoptosis markers on day 8 of RRT were associated with RRT dependence and death.

Outcomes of patients with end-stage renal disease (ESRD) under chronic hemodialysis requiring continuous renal replacement therapy (CRRT) and patients without ESRD in acute kidney injury requiring CRRT: a single-center study

In most continuous renal replacement therapy (CRRT) studies, end-stage renal disease (ESRD) patients were excluded and the outcomes of patients with ESRD treated with chronic hemodialysis (HD) were unknown. The purposes of this study were to (1) evaluate short-term patient survival and (2) compare the survival of conventional HD patients needing CRRT with the survival of non-ESRD patients in acute kidney injury (AKI) requiring CRRT. We evaluated adults (>18 years) requiring CRRT who were treated in the intensive care unit (ICU) at Kosin University Gospel Hospital from January 1, 2009 to December 31, 2010. A total of 100 (24 ESRD, 76 non-ESRD) patients underwent CRRT during the study period. Patients were divided into two major groups: patients with ESRD requiring chronic dialysis and patients without ESRD (non-ESRD) with AKI. We compared the survival of conventional HD patients requiring CRRT with the survival of non-ESRD patients in AKI requiring CRRT. For non-ESRD patients, the 90-day survival rate was 41.6%. For ESRD patients, the 90-day survival rate was 55.3%. Multivariate Cox proportional hazards analyses demonstrated that conventional HD was not a significant predictor of mortality (hazard ratio [HR]: 0.334, 95% confidence interval [CI]: 0.063-1.763, P = 0.196), after adjustment for age, gender, presence of sepsis, APACHE score, use of vasoactive drugs, number of organ failures, ultrafiltration rate, and arterial pH. The survival rates of non-ESRD and ESRD patients requiring CRRT did not differ; ESRD with conventional HD patients may be not a significant predictor of mortality.

Effect of the intensity of continuous renal replacement therapy in patients with sepsis and acute kidney injury: a single-center randomized clinical trial

INTRODUCTION

Acute kidney injury (AKI) is a major complication in patients with sepsis and is an independent predictor of mortality. However, the optimal intensity of renal replacement therapy for such patients is still controversial.

METHODS

From 1 January 2004 to 30 September 2009, we randomly assigned 280 patients with sepsis and AKI to continuous renal replacement therapy by high-volume hemofiltration (50 mL/kg/h, HVHF) or extra high-volume hemofiltration (85 mL/kg/h, EHVHF). The primary study outcome was death from any cause within 28, 60 and 90 days. Results were analyzed by univariate and multivariate methods and by Kaplan-Meier survival curves.

RESULTS

A total of 141 patients were given EHVHF and 139 were given HVHF. The two groups had similar baseline characteristics and received treatment for an average of 9.38 days (EHVHF group) and 8.88 days (HVHF group). There were no significant differences between the groups in number of deaths at 28, 60 or 90 days. There were also no differences between the groups in renal outcome of survivors at 90 days. Multivariate analysis indicated that inotropic support by norepinephrine, time in hospital of >7 days, blood platelet count <8 × 10(9)/L, Acute Physiological and Chronic Health Evaluation (APACHE) II score >25, total bilirubin >100 μmol/L, prothrombin time >18 s, serum creatinine <250 μmol/L and blood urea nitrogen >20 mmol/L were independent risk factors for death at 90 days after initiation of renal replacement therapy.

CONCLUSIONS

In patients with sepsis and AKI, increasing the intensity of renal replacement therapy from 50 (HVHF) to 85 mL/kg/h (EHVHF) had no effect on survival at 28 and 90 days.

Technical advances in renal replacement therapy

Critically ill patients are subject to several risk factors for organ injury: surgical intervention, trauma, rhabdomyolysis, hemodynamic instability, organ hypoperfusion, bacteremia and endotoxemia, sepsis and septic shock. These conditions may cause acute kidney injury (AKI), myocardial dysfunction, liver failure, coagulation abnormalities, acute lung injury (ALI), adult respiratory distress syndrome (ARDS), bone marrow depression, loss of acid/base homeostasis, and finally, brain dysfunction. The resulting picture of multiple organ dysfunction syndrome (MODS) is a lethal clinical entity that is refractory to all therapies in the majority of cases. According to the "humoral theory of sepsis", soluble substances circulate in blood and participate in the generation of the different disorders of MODS; thus, AKI is not the only clinical disorder observed in intensive care unit (ICU) patients nor is it an isolated syndrome. Current extracorporeal management of such patients focuses mainly on renal replacement therapy (RRT). Nevertheless, in recent years, technical evolution of extracorporeal devices led to the potential creation of multiple organ support therapy (MOST) in order to provide a comprehensive replacement of multiorgan dysfunction: hence, other organs (liver, heart, lungs) and syndromes (abdominal sepsis, septic shock) can today be consistently supported and bridged. The technical advances of extracorporeal equipment, moreover, might allow today the design of a dedicated pediatric RRT device in order to treat patients below 10 kg, with the safety and adequacy standards that are currently granted to the adult population. This review will describe the technical evolution of MOST machines and current literature available on MOST.

Management of septic shock

Septic shock is an important cause of mortality in children with sepsis. The incidence of septic shock is 2-4% of admissions in western pediatric intensive care units and 40%-67% for Indian PICUs. Early goal-directed resuscitation that includes aggressive fluid resuscitation of up to 60 mL/kg as boluses of 20 mL/kg by IV push, to achieve desired heart rates and blood pressure, has emerged as mainstay of treatment in the initial stage. Crystalloids are the preferred fluids, while colloids may be used in some situations. Fluid refractory shock warrants use of vasoactive drugs. Dopamine is the first choice. Dobutamine and low dose epinephrine are the preferred inotropic drugs while nor-epinephrine is a vasopressor. Children with cold shock and normal blood pressure may benefit from nitrosodilators like nitroprusside and nitroglycerine. Inodilators such as milrinone are also useful in this situation. Targeting clinical therapeutic end-points assists the management. Good supportive care is also essential for improving the outcomes.

The implications and management of septic acute kidney injury

Sepsis is the most common and severe cause of morbidity and mortality among critically ill patients. Multiple organ dysfunction syndrome often complicates sepsis, leading to a worse prognosis that is proportional to the severity and number of damaged organs. Acute kidney injury (AKI) also complicates sepsis, with a linear relationship between the severity of kidney damage and sepsis prognosis. The management of sepsis and septic AKI involves intensive proactive preventive measures, medical and extracorporeal treatment of established sepsis, support of failing organs and rehabilitation of the residual effects left by this devastating syndrome. Unfortunately, although some innovations in the clinical management of sepsis are now available, their beneficial effects on renal function are still uncertain. The aim of this Review is to provide an update on the current state of interventions in sepsis-related AKI. Prevention, pharmacological support and extracorporeal blood purification for septic AKI will be reviewed and discussed.

Adjunctive continuous high-volume hemofiltration in patients with acute severe pancreatitis: a prospective nonrandomized study

OBJECTIVES

To evaluate the efficacy of adjunctive continuous high-volume hemofiltration (HVHF) in patients with severe acute pancreatitis.

METHODS

Seventy-five patients admitted to the intensive care unit for severe acute pancreatitis from July 2006 to May 2009 were given informed consent and were followed prospectively. Patients were divided into 4 groups according to whether they accepted continuous HVHF (42 vs 33) and if they showed signs of acute kidney injury.

RESULTS

Patients of the 4 groups were comparable at baseline. The 28-day survival rate was higher in patients who accepted HVHF (81% vs 57.6%, P=0.026), especially in those without acute kidney injury (95% vs 66.7, P=0.026). Furthermore, after 72 hours of therapy, the patients who accepted HVHF had significantly better Acute Physiology and Chronic Health Evaluation II scores (16.8±4.37 vs 13.39±3.17; P<0.05), body temperature (38.2°C±1.01°C vs 37.73°C±0.95°C; P<0.05), urine volume (1186±841 mL vs 2381±2462 mL; P<0.05), and base excess (-6.3±4.5 vs 0.64±3.4; P<0.05). However, the improvement in patients who did not accept HVHF was not so obviously.

CONCLUSION

High-volume hemofiltration was associated with improved clinical outcome in acute pancreatitis patients, and should be initiated before kidney injury appearance.

Adjunctive continuous high-volume hemofiltration in acute severe pancreatitis patients: a retrospective study

OBJECTIVE. To evaluate the efficacy of continuous high-volume hemofiltration for the treatment of severe acute pancreatitis patients and the impact of acute physiology and chronic health evaluation (APACHE) II score on the efficacy of high-volume hemofiltration. MATERIAL AND METHODS. A total of 63 patients diagnosed with severe acute pancreatitis between January 2005 and July 2007 were retrospectively analyzed: 34 accepted adjunctive continuous high-volume hemofiltration (HVHF group); and 29 only accepted conventional recommended treatments (control group). RESULTS. There were no differences in physiological characteristics between the two groups when entering the intensive care unit. After treatment, the percentages of patients successfully weaned from mechanical ventilation (p = 0.004) and who experienced renal function recovery (p = 0.046) were significantly higher in the HVHF group than in the control group. The 28-day survival rate was 91.2% in the HVHF group, compared with 65.5% in the control group (p = 0.014). For patients with APACHE II scores > 15, survival was significant higher in the HVHF group than in the control group (87.5% vs 50%; p = 0.044). No difference in survival was found in patients with APACHE II scores < or = 15 between the two groups (94.4% vs 76.5%; p = 0.177). After HVHF therapy, APACHE II score, body temperature, urine volume and laboratory indices, including serum creatinine, base excess and blood calcium, were significantly improved. CONCLUSIONS. Adjunctive continuous HVHF was beneficial for the survival of severe acute pancreatitis patients. Survival improvement was significant in patients with APACHE II score > 15.