Artificial organ treatment for multiple organ failure, acute renal failure, and sepsis: recent new trends

Manifold epigenetics: A conceptual model that guides engineering strategies to improve whole-body regenerative health

Despite the promising advances in regenerative medicine, there is a critical need for improved therapies. For example, delaying aging and improving healthspan is an imminent societal challenge. Our ability to identify biological cues as well as communications between cells and organs are keys to enhance regenerative health and improve patient care. Epigenetics represents one of the major biological mechanisms involving in tissue regeneration, and therefore can be viewed as a systemic (body-wide) control. However, how epigenetic regulations concertedly lead to the development of biological memories at the whole-body level remains unclear. Here, we review the evolving definitions of epigenetics and identify missing links. We then propose our Manifold Epigenetic Model (MEMo) as a conceptual framework to explain how epigenetic memory arises and discuss what strategies can be applied to manipulate the body-wide memory. In summary we provide a conceptual roadmap for the development of new engineering approaches to improve regenerative health.

Risk factors and outcomes of neonates with acute kidney injury needing peritoneal dialysis: Results from the prospective TINKER (The Indian PCRRT-ICONIC Neonatal Kidney Educational Registry) study

BACKGROUND

Acute kidney injury (AKI) is common in neonates admitted to neonatal intensive care units (NICUs). There is a need to have prospective data on the risk factors and outcomes of acute peritoneal dialysis (PD) in neonates. The use of kidney replacement therapy in this population compared to older populations has been associated with worse outcomes (mortality rates 17-24%) along with a longer stay in the NICU and/or hospital.

METHODS

The following multicentre, prospective study was derived from the TINKER (The Indian PCRRT-ICONIC Neonatal Kidney Educational Registry) database, assessing all admitted neonates ≤28 days who received intravenous fluids for at least 48 h. The following neonates were excluded: death within 48 h, presence of any lethal chromosomal anomaly, requirement of congenital heart surgery within the first 7 days of life and those receiving only routine care in nursery. Demographic data (maternal and neonatal) and daily clinical and laboratory parameters were recorded. AKI was defined according to the Neonatal Kidney Disease: Improving Global Outcomes criteria.

RESULTS

Of the included 1600 neonates, a total of 491 (30.7%) had AKI. Of these 491 neonates with AKI, 44 (9%) required PD. Among neonates with AKI, the odds of needing PD was significantly higher among those with significant cardiac disease (odds ratio (95% confidence interval): 4.95 (2.39-10.27); p < 0.001), inotropes usage (4.77 (1.98-11.51); p < 0.001), severe peripartum event (4.37 (1.31-14.57); p = 0.02), requirement of respiratory support in NICU (4.17 (1.00-17.59); p = 0.04), necrotising enterocolitis (3.96 (1.21-13.02); p = 0.03), any grade of intraventricular haemorrhage (3.71 (1.63-8.45); p = 0.001), evidence of fluid overload during the first 12 h in NICU (3.69 (1.27-10.70); p = 0.02) and requirement of resuscitation in the delivery room (2.72 (1.45-5.12); p = 0.001). AKI neonates with PD as compared to those without PD had a significantly lower median (interquartile range) duration of stay in NICU (7 (4-14) vs. 11 (6-21) days; p = 0.004), but significantly higher mortality (31 (70.5%) vs. 50 (3.2%); p < 0.001). This discrepancy is likely attributable to the critical state of the neonates with AKI.

CONCLUSIONS

This is the largest prospective, multicentre study specifically looking at neonatal AKI and need for dialysis in neonates. AKI was seen in 30.7% of neonates (with the need for acute PD in 9% of the AKI group). The odds of needing acute PD were significantly higher among those with significant cardiac disease, inotropes usage, severe peripartum event, requirement of respiratory support in NICU, necrotising enterocolitis, any grade of intraventricular haemorrhage, evidence of fluid overload more than 10% during the first 12 h in NICU and requirement of resuscitation in the delivery room. AKI neonates with PD as compared to AKI neonates without PD had a significantly higher mortality. There is a need to keep a vigilant watch in neonates with risk factors for the development of AKI and need for PD.

Acute peritoneal dialysis is an efficient and reliable alternative therapy in preterm neonates with acute kidney injury

BACKGROUND

This study aimed to assess the underlying causes and outcomes of acute peritoneal dialysis (APD) and the complications of PD procedure in preterm neonates with acute kidney injury (AKI).

METHODS

A retrospective study of 21 preterm neonates who underwent APD in a neonatal intensive care unit (NICU) in Peking University Third Hospital between 2016 and 2019 was conducted. The demographic, clinical, biochemistry, and PD procedure--related information of the neonates was analyzed.

RESULTS

Of the 21 preterm neonates, the average gestational age (GA) was 28.9±2.6 weeks, and the average birth weight was 1,226.7±495.3 g, and included 5 (23.8%) low-birth-weight infants (LBWIs), 7 (33.3%) very LBWIs (VLBWIs), and 9 (42.9%) extremely LBWIs (ELBWIs). The major underlying causes for APD were asphyxia (66.7%, n=14) and twin-twin transfusion syndrome (47.6%, n=10). PD procedure-related complications mainly involved inadequate drainage (n=5, 23.8%) and drainage infections (n=2, 9.5%). The median duration of PD was 3 days (range, 1 hour-20 days). Compared to pre-PD, blood urea nitrogen (BUN) and serum K⁺ levels were significantly decreased post-PD (P<0.05). After PD, edema disappeared in 77.8% (n=14/18) of patients, and 42.9% patients (n=9/21) gained normal urine output. Although 8 of the 21 (38.1%) patients died and 6 (29.6%) abandoned therapy, 7 (33.3%) patients including 1 VLBWI and 3 ELBWI survived.

CONCLUSIONS

APD is an efficient and reliable alternative route of renal replacement therapy particularly for reducing BUN and K⁺ levels in preterm neonates with AKI. APD is practicable in critically ill preterm neonates, even in LBWIs and ELBWIs.

Blood purification therapy with a hemodiafilter featuring enhanced adsorptive properties for cytokine removal in patients presenting COVID-19: a pilot study

Background

Systemic inflammation in COVID-19 often leads to multiple organ failure, including acute kidney injury (AKI). Renal replacement therapy (RRT) in combination with sequential extracorporeal blood purification therapies (EBP) might support renal function, attenuate systemic inflammation, and prevent or mitigate multiple organ dysfunctions in COVID-19.

Aim

Describe overtime variations of clinical and biochemical features of critically ill patients with COVID-19 treated with EBP with a hemodiafilter characterized by enhanced cytokine adsorption properties.

Methods

An observational prospective study assessing the outcome of patients with COVID-19 admitted to the ICU (February to April 2020) treated with EBP according to local practice. Main endpoints included overtime variation of IL-6 and multiorgan function-scores, mortality, and occurrence of technical complications or adverse events.

Results

The study evaluated 37 patients. Median baseline IL-6 was 1230 pg/ml (IQR 895) and decreased overtime (p < 0.001 Kruskal-Wallis test) during the first 72 h of the treatment, with the most significant decrease in the first 24 h (p = 0.001). The reduction in serum IL-6 concentrations correlated with the improvement in organ function, as measured in the decrease of SOFA score (rho = 0.48, p = 0.0003). Median baseline SOFA was 13 (IQR 6) and decreased significantly overtime (p < 0.001 at Kruskal-Wallis test) during the first 72 h of the treatment, with the most significant decrease in the first 48 h (median 8 IQR 5, p = 0.001).

Compared to the expected mortality rates, as calculated by APACHE IV, the mean observed rates were 8.3% lower after treatment. The best improvement in mortality rate was observed in patients receiving EBP early on during the ICU stay. Premature clotting (running < 24 h) occurred in patients (18.9% of total) which featured higher effluent dose (median 33.6 ml/kg/h, IQR 9) and higher filtration fraction (median 31%, IQR 7.4). No electrolyte disorders, catheter displacement, circuit disconnection, unexpected bleeding, air, or thromboembolisms due to venous cannulation of EBP were recorded during the treatment. In one case, infection of vascular access occurred during RRT, requiring replacement.

Conclusions

EBP with heparin-coated hemodiafilter featuring cytokine adsorption properties administered to patients with COVID-19 showed to be feasible and with no adverse events. During the treatment, patients experienced serum IL-6 level reduction, attenuation of systemic inflammation, multiorgan dysfunction improvement, and reduction in expected ICU mortality rate.

Th17/Treg imbalance in patients with severe acute pancreatitis: Attenuated by high-volume hemofiltration treatment

BACKGROUND

To investigate the effect of high-volume hemofiltration (HVHF) on Th17/Treg imbalance in patients with severe acute pancreatitis (SAP).

METHODS

Forty-two patients with SAP were randomly received 24 hours of continuous HVHF (n = 21) or without HVHF (n = 21). At day 28, all 42 patients were divided into survival group (n = 32) and non-survival group (n = 10). Venous blood samples collected at 0, 6, 12, and 24 hours during HVHF treatment (or equivalent time in non-HVHF group) were assessed by flow cytometry to detect Th17 and Treg cells. Concentrations of IL-6, IL-17, IL-10, and TGF-β1 were detected by enzyme-linked immunosorbent assay.

RESULTS

Th17%, Treg%, Th17/Treg, and levels of related cytokines were significantly higher in SAP patients than healthy controls (P < .05), and these changes were more pronounced in SAP patients with multiple organ failure than those with single organ failure (P < .05). After HVHF treatment, Th17%, Treg%, Th17/Treg, IL-6, IL-17, and IL-10 significantly reduced (P < .05), while there were no significant changes in non-HVHF group (P > .05). In addition, acute physiology and chronic health evaluation II and sequential organ failure assessment scores decreased markedly after HVHF treatment. Baselines of Th17%, Treg%, Th17/Treg, and related cytokines were significantly higher in non-survival group than survival group. Both acute physiology and chronic health evaluation I score and IL-6 level were positively correlated with Th17% before and after HVHF treatment (P < .01).

CONCLUSIONS

Th17/Treg imbalance is present in SAP and may be correlated with its severity and prognosis. HVHF effectively attenuates the Th17/Treg imbalance in SAP patients. The beneficial effect of HVHF on Th17/Treg imbalance is possibly associated with removing excess inflammatory mediators.

Acute peritoneal dialysis in neonatal intensive care unit: An 8-year experience of a referral hospital

BACKGROUND

The aim of present study was to evaluate the indications, complications and outcomes of acute peritoneal dialysis (APD) in neonates at a referral university hospital during the previous 8 years.

METHODS

This retrospective analysis included a total of 52 newborn infants who underwent APD in a neonatal intensive care unit between January 2008 and March 2016. Demographic, clinical, laboratory and microbiological data were extracted from patients' medical files.

RESULTS

The primary causes for requiring APD were acute tubular necrosis (n = 36, 69.2%), inborn error of metabolism (n = 10, 19.2%), congenital nephrotic syndrome (n = 2, 3.9%), bilateral polycystic kidney (n = 2, 3.9%), renal agenesis (n = 1, 1.9%), and obstructive uropathy (n = 1, 1.9%). The mean duration of APD was 8.7 ± 15.87 days (range: 1-90 days). Procedural complications were mainly hyperglycemia (n = 16, 47.1%), dialysate leakage (n = 7, 20.6%), peritonitis (n = 3, 8.8%), catheter obstruction (n = 3, 8.8%), bleeding at the time of catheter insertion (n = 2, 5.9%), catheter exit site infection (n = 2, 5.9%), and bowel perforation (n = 1 2.9%). There were 40 deaths (76.9%), mainly due to underlying causes. Ten of the 12 survivors showed full renal recovery, but mild chronic renal failure (n = 1) and proteinuria with hypertension were seen (n = 1) in each of remaining patients.

CONCLUSION

Peritoneal dialysis is an effective route of renal replacement therapy in the neonatal period for management of metabolic disturbances as well as renal failure. Although major complications of the procedure are uncommon, these patients still have a high mortality rate due to serious nature of the underlying primary causes.

Plasma Filtration Adsorption Dialysis (PFAD): A New Technology for Blood Purification

Severe sepsis is one of the most significant challenges in critical care. Despite all the developments achieved in infectious diseases and critical care, along with numerous attempts to develop treatments, the mortality rate of severe sepsis and septic shock remains unacceptably high. The pathophysiology of severe sepsis and septic shock is only partially understood. Circulating pro-inflammatory and anti-inflammatory mediators appear to participate in the complex cascade of events which leads to deranged microcirculatory function, as we know from the peak concentration hypothesis.

Therapeutic trials targeting single pro-inflammatory and anti-inflammatory mediators failed to demonstrate any benefit, suggesting that the unselective removal of different mediators may be a more appropriate approach.

In severe sepsis several blood purification techniques, such as continuous hemofiltration (CVVH), high volume hemofiltration (HVHF), pulse high volume hemofiltration (HVHF), plasma filtration, plasma adsorption, coupled plasma filtration adsorption (CPFA), have been proposed but such techniques appear to have both theorical as well as practical limitations.

Plasma Filtration Adsorption Dialysis (PFAD) is a new extracorporeal treatment which combines different principles of blood purification in a single device. The core of this technique is a new dialyzer composed by three suitable compartments that provide specific functions. The association of multiple principles permits specific removal of molecules implicated in the pathophysiology of patient's disease and re-establishment of hydro-electrolyte, acid-base equilibrium, if renal dysfunction-failure is present. The final target of PFAD is to obtain complete purification by combining principles of physics and chemistry to remove hydrophilic and hydrophobic molecules with a very wide range of weights.

Intestinal mucosal barrier dysfunction in SAP patients with MODS ameliorated by continuous blood purification

BACKGROUND

Dysfunction of the intestinal mucosal barrier plays an important role in the pathophysiology of severe acute pancreatitis (SAP). Continuous blood purification (CBP) has been shown to improve the prognosis of SAP patients. In order to investigate the effect of CBP on intestinal mucosal barrier dysfunction in SAP patients with MODS, we conducted in vivo and in vitro experiments to explore the underlying mechanisms.

METHODS

The markers for the assessment of intestinal mucosal barrier function including serum diamine oxidase (DAO), endotoxin and intestinal epithelial monolayer permeability were detected during CBP therapy. The distribution and expression of cytoskeleton protein F-actin and tight junction proteins claudin-1 were observed. In addition, Rho kinase (ROCK) mRNA expression and serum tumor necrosis factor-alpha (TNF-α) levels during CBP were determined.

RESULTS

SAP patients with MODS had increased levels of serum DAO, endotoxin and intestinal epithelial monolayer permeability when compared with normal controls. While the distribution of F-actin and claudin-1 was rearranged, and the expression of claudin-1 significantly decreased, but F-actin had no change. Meanwhile, ROCK mRNA expression and serum TNF-α level were increased. However, after CBP treatment, levels of serum DAO, endotoxin and intestinal epithelial monolayer permeability decreased. The F-actin and claudin-1 reorganization attenuated and the expression of claudin-1 increased. At the same time, ROCK mRNA expression and serum TNF-α level were decreased.

CONCLUSIONS

CBP can effectively improve intestinal mucosal barrier dysfunction. The beneficial effect is associated with the improvement of cytoskeleton and tight junction proteins in stability by downregulation of ROCK mRNA expression through the removal of excess proinflammatory factors.

The Use of Acute Peritoneal Dialysis in Critically Ill Newborns

Background

To evaluate the efficacy, complications, and mortality rate of acute peritoneal dialysis (APD) in critically ill newborns.

Material/Methods

The study included 31 newborns treated in our center between May 2012 and December 2014.

Results

The mean birth weight, duration of peritoneal dialysis, and gestational age of the patients were determined as 2155.2±032.2 g (580–3900 g), 4 days (1–20 days), and 34 weeks (24–40 weeks), respectively. The main reasons for APD were sepsis (35.5%), postoperative cardiac surgery (16%), hypoxic ischemic encephalopathy (13%), salting of the newborn (9.7%), congenital metabolic disorders (6.1%), congenital renal diseases (6.5%), nonimmune hydrops fetalis (6.5%), and acute kidney injury (AKI) due to severe dehydration (3.2%). APD-related complications were observed in 48.4% of the patients. The complications encountered were catheter leakages in nine patients, catheter obstruction in three patients, peritonitis in two patients, and intestinal perforation in one patient. The general mortality rate was 54.8%, however, the mortality rate in premature newborns was 81.3%.

Conclusions

APD can be an effective, simple, safe, and important therapy for renal replacement in many neonatal diseases and it can be an appropriate treatment, where necessary, for newborns. Although it may cause some complications, they are not common. However, it should be used carefully, especially in premature newborns who are vulnerable and have a high mortality risk. The recommendation of APD therapy in such cases needs to be verified by further studies in larger patient populations.

Improving RhoA-mediated intestinal epithelial permeability by continuous blood purification in patients with severe acute pancreatitis

BACKGROUND

Early dysfunction of the intestinal mucosal barrier contributes to increasing intestinal permeability. It may play an important role in the pathophysiology of severe acute pancreatitis (SAP). A rising number of clinical data have showed that continuous blood purification (CBP) may improve the prognosis of SAP. However, the therapeutic effects of CBP on intestinal epithelial permeability have been rarely reported.

METHODS

Intestinal epithelial monolayer (Caco-2) was incubated with serum samples collected at specific time points from SAP patients during CBP. Changes in intestinal epithelial monolayer permeability and configuration, and levels of cellular tight junction structural proteins including occludin and ZO-1, and RhoA mRNA expression level were recorded, respectively. In addition, serum tumor necrosis factor-alpha (TNF-α) levels at specific time points during CBP were determined.

RESULTS

Before CBP initiation, intestinal epithelial permeability was increased and tight junction structural protein level was decreased and reorganized, but RhoA mRNA expression and serum TNF-α were increased. However, after CBP treatment, intestinal epithelial permeability was reduced and tight junction protein levels were increased, with reorganization attenuated. Meanwhile, RhoA mRNA expression and serum TNF-α level was decreased.

CONCLUSIONS

After CBP treatment, intestinal epithelial permeability was reduced by increasing occludin and ZO-1 protein level and attenuating reorganization. This beneficial effect of CBP on intestinal epithelial permeability is associated with down-regulation of RhoA mRNA expression, and it may be related to the removal of TNF-α by CBP.

Continuous blood purification ameliorates endothelial hyperpermeability in SAP patients with MODS by regulating tight junction proteins via ROCK

BACKGROUND

Excessive activation of inflammatory mediator cascade during severe acute pancreatitis (SAP) is a major cause of multiple organ dysfunction and is associated with a high mortality. Recently, more and more studies have shown that continuous blood purification (CBP) could improve the prognosis of patients with multiple organ dysfunction syndrome (MODS), but the exact mechanism is still unclear. Many researchers have found that the disruption of tight junction barrier was an important factor for endothelial hyperpermeability, which played a key role in the pathogenesis of MODS. Previously, we found CBP could attenuate endothelial hyperpermeability in SAP patients with lung injury through regulating cytoskeleton reorganization mediated by RhoA/ROCK. However, the effect of CBP on the change of tight junction proteins in SAP patients with MODS was still unknown. This study aimed to investigate the role of tight junctions in endothelial hyperpermeability in SAP patients with MODS using an in vitro model, and the effect of CBP on tight junction barrier.


METHODS

Before CBP and after CBP, blood samples were collected to observe hepatic and renal function, and arterial blood gas, while the APACHE II score was calculated to evaluate the severity of patients. To test whether RhoA/ROCK signaling pathway was involved, human umbilical vein endothelial cells (HUVECs) were exposed to serum samples taken from patients at specific time points during CBP, or preincubated with ROCK inhibitor, Y-27632, followed by treatment with serum. Then, the changes in endothelial cell permeability and the expression and distribution of tight junction proteins occludin and claudin-1 were observed. 


RESULTS

Compared with before CBP, the APACHE II score, serum creatinine and alanine aminotransferase decreased significantly, while PaO2/FiO2 increased significantly after CBP. Meanwhile, endothelial permeability induced by serum from patients significantly increased, while the expression of tight junction proteins occludin and claudin-1 significantly decreased, and severe disruption of occludin and claudin-1 was found in these cells. However, pretreated with Rho-kinase inhibitor, Y-27632 could lessen all of these abnormalities, and in a dose-dependent way. Endothelial hyperpermeability, the abnormal expression and distribution of occludin and claudin-1 were attenuated in HUVECs treated with serum from patients after CBP treatment. 


CONCLUSIONS

The abnormality of tight junctions mediated by ROCK was an important mechanism for endothelial hyperpermeability induced by serum from SAP patients with MODS. CBP could ameliorate the disorganization and redistribution of tight junction proteins, hence improve the endothelial permeability.

Continuous blood purification ameliorates RhoA-mediated endothelial permeability in severe acute pancreatitis patients with lung injury

BACKGROUND

In the early phase of severe acute pancreatitis (SAP), serious pulmonary complications which are directly correlated with mortality are very common. Endothelial injury has been shown to play a key role in the pathogenesis of ALI/ARDS. Continuous blood purification (CBP) has been widely used in treating patients with multiple organ dysfunction syndrome (MODS) including ARDS. However, the impact of CBP on endothelial function has been little studied.

METHODS

Human umbilical vein endothelial cells (HUVECs) were exposed to serum samples or replacement fluid taken from patients at specific time points during CBP, or pretreated with Y-27632 followed by treatment with serum, then, changes in cytoskeletal configuration, endothelial monolayer permeability, and RhoA activation were studied.

RESULTS

Endothelial permeability, RhoA activity, and stress fiber reorganization increased in HUVECs treated with serum from patients before CBP initiation, and lessened in HUVECs treated with serum from patients after CBP initiation. Endothelial hyperpermeability and stress fiber reorganization reduced in HUVECs pretreated with Rho-kinase inhibitor, Y-27632, and in a dose-dependent fashion. Endothelial permeability and RhoA activity increased in HUVECs treated with waste replacement fluid collected 2 h after CBP initiation.

CONCLUSIONS

After CBP treatment, endothelial hyperpermeability induced by serum from SAP patients with lung injury was reduced. The inhibition of RhoA-mediated F-actin remodeling might be the mechanism.

[High volume hemofiltration in septic shock]

Severe sepsis and septic shock are conditions associated with high morbidity and mortality. The disproportionate release of pro-inflammatory and anti-inflammatory mediators caused by the septic insult is the promoter of multiple organ dysfunction. Conventional hemodialysis, hemofiltration or a combination of both can be a good option to replace the deteriorating renal function in critically ill patients by the removal of nitrogen compounds (small molecules). However, this "renal dose" is insufficient for the removal of inflammatory mediators (medium molecules), and therefore contributes little to the cardiovascular stabilization of patients with septic shock. In this setting, a higher dose of ultrafiltration (> 50 ml/kg/h) or "septic dose" may be needed. In this review article, we have analyzed the clinical and pathophysiological rationale for the use of high volume hemofiltration in patients with septic shock.

Extracorporeal cell therapy with granulocytes in a pig model of Gram-positive sepsis

OBJECTIVES

Granulocyte transfusions have been used to treat immune cell dysfunction in sepsis. As granulocyte transfusions can trigger tissue injury via local effects of neutrophils, we hypothesized that extracorporeal treatment of plasma using granulocytes would prove beneficial while having less side effects.

DESIGN

Prospective controlled three-armed animal study.

SETTING

Research laboratory.

SUBJECTS

Twenty-one female immature pigs (7.5-12 kg, 7-9 weeks old).

INTERVENTIONS

Three groups of spontaneously breathing, sedated pigs (n = 7 each) received an intravenous lethal dose of live Staphylococcus aureus over 1 hour. Although group I had no specific treatment (control), group II and III were subsequently treated for 4 hours with an extracorporeal device containing either no cells (sham control, group II) or human cell line-derived granulocytic cells (group III). Survival time and physiologic, biochemical, and hematologic parameters were monitored for 7 days.

MEASUREMENTS AND MAIN RESULTS

All animals of group I died during the observation time (mean survival time: 70 hours). In group II, two of seven and in group III, six of seven animals survived the observation time (mean survival: 75 and 168 hours, respectively). Survival differences were significant between group I and III (p < 0.001) and between group II and III (p < 0.05) but not between group I and II (p = 0.43). Furthermore, group differences in bacterial blood concentrations, differential blood count, blood gases, lactate, and interleukins were observed. The extracorporeal cell treatment was well tolerated by the animals.

CONCLUSIONS

Extracorporeal therapy with granulocytic cells significantly improved survival in a pig model of sepsis. Further studies with this approach are encouraged.

Renal replacement therapies in pediatric intensive care patients: experiences of one center in Turkey

BACKGROUND

Despite constant improvements in caring for critically ill neonates and infants with congenital cardiac disease, sepsis, bone marrow and solid organ transplantation, acute renal failure (ARF) is an important problem in these children. ARF, severe fluid overload and inborn errors of metabolism are some of the indications for acute dialysis in infants and children.

METHODS

The authors had retrospectively evaluated the medical records of Pediatric Intensive Care Unit, Ankara University School of Medicine, Ankara, Turkey patients who had required acute renal replacement therapy between the dates of January 2002 to February 2005.

RESULTS

Medical records of 332 patients were reviewed. Acute renal replacement therapy was performed in 21 patients (6.3%; mean age, 9.6 +/- 7.4 years). Dialysis modalities were peritoneal dialysis in 15 patients (71.4%; mean age, 3.9 +/- 5.6 years) and hemodialysis in six patients (28.6%; mean age, 12.1 +/- 3.2 years). A total of 90% of patients had severe systemic disease leading to ARF. A total of 95% of patients had multiple organ dysfunction syndrome. The most common cause of ARF was refractory shock. At the beginning of renal replacement therapy, 10 patients were anuric, nine patients had volume overload, seven patients had decompensated metabolic acidosis and nine patients had hypotension. The average dialysis period was 4.7 +/- 6.4 days. Mortality rate was 66.7%. Eight patients recovered from ARF and chronic renal failure had developed in one patient.

CONCLUSION

In the Pediatric Intensive Care Unit, ARF is frequently seen together with multiple organ dysfunction syndrome and the mortality rate is high. Both peritoneal dialysis and hemodialysis are important renal replacement treatment modalities in patients with ARF. The age and hemodynamic status of the patients are important when choosing treatment modality; generally peritoneal dialysis is preferred in infants and toddler, while hemodialysis is preferred in older children.

Current status of dosing and quantification of acute renal replacement therapy. Part 2: dosing paradigms and clinical implementation

The dosing and quantification of acute renal replacement therapy has emerged as one of the most pressing issues in the management of critically-ill patients with acute kidney injury. Although there is ongoing debate as to the best marker of uraemic injury in this setting, several landmark studies have identified clearance-related expressions of acute renal replacement therapy dose as important determinants of survival. Part 1 of this review examined the factors affecting the delivery of prescribed acute renal replacement therapy dose. Part 2 summarises and contextualises findings from recent dose-outcome studies, and reviews clinical tools to assist in the prescription and quantification of acute renal replacement therapy dose.

Continuous renal replacement therapy in patients following traumatic injury

In critically injured patients, the incidence of acute renal failure has been reported to occur in as many as 31% of patients. The use of CRRT modalities for patients following traumatic injuries is becoming more common, albeit slowly, and this therapy may impact upon long-term recovery of renal function and mortality. Historical studies investigating the early use of intermittent dialysis reported significant improvement in survival in patients who were dialyzed earlier and more vigorously than in control subjects. Early trauma patients also showed improved survival following war injuries when dialyzed prophylactically. Although there is a growing acceptance in favor of earlier renal replacement therapy, the published consensus and the practice in many centers has been to dialyze/filter relatively ill rather than relatively healthy patients. The R Adams Cowley Shock Trauma Center (STC) in Baltimore, Maryland, USA, admits over 8,000 trauma patients each year. Within the STC, a program of continuous renal replacement therapy was established in the early 1980's. We review both historical and current literature on the use of renal replacement therapies after traumatic injury, and suggest some future areas of investigation and indications for these modalities.

Extracorporeal Therapies in the Treatment of Sepsis: Experience and Promise

Desire to restore the balance of body elements has enamored physicians since the ancient practice of bloodletting. More recently, extracorporeal techniques have been employed in both adults and children in treating sepsis. Extracorporeal therapies include continuous renal replacement (CRRT), plasma-based removal techniques, and extracorporeal membrane oxygenation (ECMO). These treatments could theoretically 1) provide immunohomeostasis of pro- and anti-inflammatory cytokines and other sepsis mediators, 2) decrease organ microthrombosis through removal of pro-coagulant factors and modulating the impaired septic coagulation response in sepsis, and 3) provide mechanical support of organ perfusion during the acute septic episode to allow time for response to traditional sepsis therapies and antimicrobials. CRRT is beneficial in managing fluid overload and acute renal failure in sepsis. Removal of sepsis mediators through the technique is variable, and the outcome impact of CRRT on sepsis has not been definitively determined. High-flow CRRT has demonstrated benefit in septic adults. Intriguing early results suggest that plasma exchange could improve outcomes in both adults and children. Based on experience, ECMO is recommended for refractory septic shock in neonates and should be considered for use in children. Ongoing trials may help determine whether the promise of extracorporeal therapies translates into outcome improvement in septic children.

Quo vadis haemapheresis. Current developments in haemapheresis

The techniques of haemapheresis originated in the development of centrifugal devices separating cells from plasma and later on plasma from cells. Subsequently membrane filtration was developed allowing for plasma-cell separation. The unspecificity of therapeutic plasma exchange led to the development of secondary plasma separation technologies being specific, semi-selective or selective such as adsorption, filtration or precipitation. In contrast on-line differential separation of cells is still under development. Whereas erythrocytapheresis, granulocytapheresis, lymphocytapheresis and stem cell apheresis are technically advanced, monocytapheresis may need further improvement. Also, indications such as erythrocytapheresis for the treatment of polycythaemia vera or photopheresis though being clinically effective and of considerable importance for an appropriate disease control are to some extent under debate as being either too costly or without sufficient understanding of the mechanism. Other forms of cell therapy are under development. Rheohaemapheresis as the most advanced technology of extracorporeal haemorheotherapy is a rapidly developing approach contributing to the treatment of microcirculatory diseases and tissue repair. Whereas the control of a considerable number of (auto-) antibody mediated diseases is beyond discussion, the indication of apheresis therapy for immune complex mediated diseases is quite often still under debate. Detoxification for artificial liver support advanced considerably during the last years, whereas conclusions on the efficacy of septicaemia treatment are debatable indeed. LDL-apheresis initiated in 1981 as immune apheresis is well established since 24 years, other semi-selective or unspecific procedures, allowing for the elimination of LDL-cholesterol among other plasma components are also being used. Correspondingly Lp(a) apheresis is available as a specific, highly efficient elimination procedure superior to techniques which also eliminate Lp(a). Quality control systems, more economical technologies as for instance by increasing automation, influencing the over-interpretation of evidence based medicine especially in patients with rare diseases without treatment alternative, more insight into the need of controlled clinical trials or alternatively improved diagnostic procedures are among others tools ways to expand the application of haemapheresis so far applied in cardiology, dermatology, haematology, immunology, nephrology, neurology, ophthalmology, otology, paediatrics, rheumatology, surgery and transfusion medicine.

Reviews: The Current State of Nonuremic Applications for Extracorporeal Blood Purification

Despite the commonly accepted indications for hemodialysis and extracorporeal depuritive techniques, some clinicians have come to rely on blood purification for clinical states where the targeted substance for removal differs from uremic waste products. Over the last decade, a number of studies have emerged to help define the application of extracorporeal blood purification (ECBP) to these "nonuremic" indications. This review describes the application of extracorporeal blood purification in clinical states including sepsis, rhabdomyolysis, congestive heart failure, hepatic failure, tumor lysis syndrome, adult respiratory distress syndrome, intravenous contrast exposure, and lactic acidosis. Additional comments are provided to review existing literature on thermoregulation and osmoregulation, including acute brain injury.

Influence of continuous veno-venous hemofiltration on the course of acute pancreatitis

AIM: To investigate whether continuous veno-venous hemofiltration (CVVH) in different filtration rate to eliminate cytokines would result in different efficiency in acute pancreatitis, whether the saturation time of filter membrane was related to different filtration rate, and whether the onset time of CVVH could influence the survival of acute pancreatitis.

METHODS: Thirty-seven patients were classified into four groups randomly. Group 1 underwent low-volume CVVH within 48 h of the onset of abdominal pain (early CVVH, n = 9). Group 2 received low-volume CVVH after 96 h of the onset of abdominal pain (late CVVH, n = 10). Group 3 underwent high-volume CVVH within 48 h of the onset of abdominal pain (early CVVH, n = 9). Group 4 received high-volume CVVH after 96 h of the onset of abdominal pain (late CVVH, n = 9). CVVH was sustained for at least 72 h. Blood was taken before hemofiltration, and ultrafiltrate was collected at the start of CVVH and every 12 h during CVVH period for the purpose of measuring the concentrations of TNF-α, IL-1β and IL-6. The concentrations of TNF-α, IL-1β and IL-6 were measured by swine-specific ELISA. The Solartron 1 255 B frequency response analyzer (British) was used to observe the resistance of filter membrane.

RESULTS: The survival rate had a significant difference (94.44% vs 68.42%, P<0.01) high-volume and low-volume CVVH patients. The survival rate had also a significant difference (88.89% vs 73.68%, P<0.05) between early and late CVVH patients. The hemodynamic deterioration (MAP, HR, CVP) was less severe in groups 4 and 1 than that in group 2, and in group 3 than in group 4. The adsorptive saturation time of filters membranes was 120-180 min if the filtration rate was 1 000-4 000 mL/h. After the first, second and third new hemofilters were changed, serum TNF-α concentrations had a negative correlation with resistance (r: -0.91, -0.89, and -0.86, respectively in group 1; -0.89, -0.85, and -0.76, respectively in group 2; -0.88, -0.92, and -0.82, respectively in group 3; -0.84, -0.87, and -0.79, respectively in group 4). The decreasing extent of TNF-α, IL-1β and IL-6 was significantly different between group 3 and group 1 (TNF-α P<0.05, IL-1β P<0.05, IL-6 P<0.01), between group 4 and group 2 (TNF-α P<0.05, IL-1β P<0.05, IL-6 P<0.01), between group 1 and group 2 (TNF-α P<0.05, IL-1β P<0.05, IL-6 P<0.05), and between group 3 and group 4 (TNF-α P<0.01, IL-1β P<0.01, IL-6 P<0.05), respectively during CVVH period. The decreasing extent of TNF-α and IL-1β was also significantly different between survival patients and dead patients (TNF-α P<0.05, IL-1β P<0.05). In survival patients, serum concentration of TNF-α and IL-1β decreased more significantly than that in dead patients.

CONCLUSION: High-volume and early CVVH improve hemodynamic deterioration and survival in acute pancreatitis patients. High-volume CVVH can eliminate cytokines more efficiently than low-volume CVVH. The survival rate is related to the decrease extent of TNF-α and IL-1β. The adsorptive saturation time of filter membranes are different under different filtration rate condition. The filter should be changed timely once filter membrane adsorption is saturated.

Dose of Dialysis in Acute Renal Failure

Acute renal failure (ARF) is a cause of significant morbidity and mortality. Despite advances in supportive care, outcomes in ARF have improved little over the past decades. The primary goals in management of patients with ARF are to optimize hemodynamic and volume status, minimize further renal injury, correct metabolic abnormalities, and permit adequate nutrition. Renal replacement therapy (RRT) is often required to achieve these goals while awaiting renal recovery, but the optimal dose of dialysis in patients with ARF is not known. Extrapolation of required dialysis dose from recommendations in chronic dialysis is unlikely to be appropriate because of the lack of a steady state and differences in distribution volume of urea that are intrinsic to ARF. The prescribed dialysis dose in ARF is often low, and actual delivered dose is often even less than prescribed. Delivery of dialysis in ARF is often hampered by the patient's hypercatabolic state, hemodynamic instability, and volume status, as well as suboptimal vascular access with temporary venous catheters. The impact of intermittent hemodialysis (IHD) versus continuous renal replacement therapy (CRRT) on outcomes in ARF is also not clear. Patient disease severity impacts more than dialysis modality in patient outcome, but when patients are stratified for equal disease severity, CRRT may have potential benefits over IHD in terms of patient survival, fluid and metabolic control, and renal recovery. Strategies associated with improved outcomes that have emerged thus far in ARF are to aim for a time-averaged blood urea nitrogen (BUN) of less than 60 mg/dl with IHD, varying IHD frequency as necessary, or to achieve a minimum ultrafiltration rate of 35 ml/kg/hr with CRRT.