Differential effects of hemofiltration and of coupled plasma filtration adsorption on cardiac repolarization in pigs with hyperdynamic septic shock

Modeling sepsis, with a special focus on large animal models of porcine peritonitis and bacteremia

Infectious diseases, which often result in deadly sepsis or septic shock, represent a major global health problem. For understanding the pathophysiology of sepsis and developing new treatment strategies, reliable and clinically relevant animal models of the disease are necessary. In this review, two large animal (porcine) models of sepsis induced by either peritonitis or bacteremia are introduced and their strong and weak points are discussed in the context of clinical relevance and other animal models of sepsis, with a special focus on cardiovascular and immune systems, experimental design, and monitoring. Especially for testing new therapeutic strategies, the large animal (porcine) models represent a more clinically relevant alternative to small animal models, and the findings obtained in small animal (transgenic) models should be verified in these clinically relevant large animal models before translation to the clinical level.

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.

Ion-Exchange Resin Anticoagulation (I-ERA): A Novel Extracorporeal Technique for Regional Anticoagulation

BACKGROUND

Extracorporeal treatments always require blood anticoagulation. We tested feasibility and efficacy of a novel technique for regional extracorporeal blood anticoagulation based on calcium removal by ion-exchange resins (i-ER), called ion-exchange resin anticoagulation (i-ERA).

METHODS

Eight swine were connected to a veno-venous extracorporeal circuit comprising a hemodiafilter and an i-ER. Blood flow was 150 mL/min. Hemodiafiltrate was generated at 975 mL/min and passed through the i-ER. A fraction of the calcium-free hemodiafiltrate was returned to the hemodiafilter (675 mL/min), while the remaining was recirculated prior the hemodiafilter (300 mL/min) to dilute blood entering the hemodiafilter. A calcium replacement solution was continuously infused. Two hours after i-ERA start, blood was sampled from inlet, before the hemodiafilter (prehemodiafilter blood) and from outlet of the extracorporeal circuit for ionized calcium (iCa) concentration and thromboelastography (TEG). Arterial blood was collected for blood gas analyses, electrolytes concentrations, and plasma free hemoglobin. Hemodynamics and ventilation were monitored.

RESULTS

i-ERA reduced iCa from 1.28 ± 0.05 mmol/L (inlet) to 0.47 ± 0.03 mmol/L (prehemodiafilter blood) and 0.25 ± 0.03 mmol/L (outlet). Prehemodiafilter blood and outlet samples showed no sign of clot formation (reaction time (R) >60 min; maximal amplitude (MA) = 0 (0-0) mm), while blood-inlet had normal coagulation (R = 8.5 (5.8-10.2) min; MA = 65.2 (63.2-68.7) mm). Arterial gas analyses and electrolytes concentrations, hemodynamics, and ventilation were unchanged. No hemolysis was recorded.

CONCLUSIONS

In a swine model, i-ERA proved feasible and effective in reducing iCa and preventing clot formation with TEG analyses. Further studies are warranted to evaluate the long-term efficacy and safety of i-ERA.

LEVEL OF EVIDENCE

V-therapeutic animal experiment.

Coupled plasma haemofiltration filtration in severe sepsis: systematic review and meta-analysis

INTRODUCTION

Coupled plasma filtration and adsorption (CPFA) has been used in the treatment of severe sepsis with the intention of removing the proinflammatory and anti-inflammatory mediators from the systemic circulation. It is believed that this interrupts and moderates the septic cascade, but there is uncertainty about the benefits of this therapy.

METHODS

A systematic review and meta-analysis were performed to estimate the effects of CPFA on mortality in severe sepsis. The Cochrane CENTRAL Register of Controlled Trials, CINAHL, EMBASE, MEDLINE-EBSCO-Host, MEDLINE and ProQuest, were searched from 1997 to 2013. Randomised controlled trials, prospective cohort studies and retrospective cohort studies were included using the Centre for Reviews and Dissemination (CRD) framework. Data were abstracted using standard pro forma, and studies independently reviewed by two authors to confirm inclusion criteria. Quality of studies and risk of bias were assessed using the Grading of Recommendations, Assessment, Development and Evaluation Working Group (GRADE) and Critical Appraisal Skills (CASP) criteria, respectively. Meta-analysis was performed using Review Manager (RevMan V.5.1) software. The primary outcome was 28-day mortality. Secondary outcomes were mediator adsorption (picograms/mL), mean arterial BP (mm Hg) and oxygenation ratio.

RESULTS

17 studies met the inclusion criteria (n=441 patients, 242 CPFA). 14 studies reported the primary outcome of 28-day mortality. There were 88 deaths in CPFA patients versus 118 in those receiving haemofiltration: OR 0.34 (95% CI 0.24 to 0.13). Point estimates of effect on the secondary outcomes of mean arterial pressure and oxygen ratio favoured CPFA. Studies were small and heterogenous.

CONCLUSIONS

Evidence for CPFA in severe sepsis is sparse, of poor quality and further research is required, however, this meta-analysis noted improvements in survival rates of those patients treated with CPFA.

In vivo antibiotic removal during coupled plasma filtration adsorption: a retrospective study

Coupled plasma filtration adsorption (CPFA) is a blood purification therapy aimed at modulating the host inflammatory response involved in sepsis pathogenesis. One potential drawback of this technique is the unexpected elimination of antibiotics. The aim of this study was to assess the elimination of several antibiotics with CPFA. We performed a retrospective analysis of the serum and ultrafiltrate concentrations of different antibiotics routinely measured during CPFA sessions in five patients experiencing septic shock. The adsorbent extraction ratio (AER) for piperacillin and vancomycin 2 h into the CPFA session were high: 95.4 ± 6.9% and 99.6 ± 0.9%, respectively. These AER decreased significantly by 8 h (at 8 h: 6.3 ± 51.8% and -30.2 ± 25.6%, respectively), suggesting saturation of the resin cartridge. Conversely, the tazobactam AER was low (7.2 ± 15% after 2 h of CPFA). No significant changes in the mean serum concentrations of piperacillin, tazobactam, and vancomycin were observed. Thus, as opposed to tazobactam, we report high adsorption of piperacillin and vancomycin on the CPFA resin but with no reduction in serum concentrations.

Coupled plasma filtration adsorption for the treatment of a patient with acute respiratory distress syndrome and acute kidney injury: a case report

Coupled plasma filtration adsorption (CPFA) is an extracorporeal blood purification therapy based on non-specific pro- and anti-inflammatory mediator adsorption on a special resin cartridge coupled with continuous veno-venous haemofiltration or continuous veno-venous haemodiafiltration and is one of the emerging treatments for septic patients. However, in the literature, there are limited data about its efficacy in treating patients with acute diseases but without the traditional criteria for sepsis. We describe the case of a 43-year-old male who developed acute respiratory distress syndrome secondary to pneumonia and acute kidney injury, whose clinical conditions rapidly improved after early CPFA therapy.

Clinical review: blood purification for sepsis

Sepsis is the primary cause of death in the intensive care unit. Extracorporeal blood purification therapies have been proposed for patients with sepsis in order to improve outcomes since these therapies can alter the host inflammatory response by non-selective removal of inflammatory mediators or bacterial products or both. Recent technological progress has increased the number of techniques available for blood purification and their performance. In this overview, we report on the latest advances in blood purification for sepsis and how they relate to current concepts of disease, and we review the current evidence for high-volume hemofiltration, cascade hemofiltration, hemoadsorption, coupled plasma filtration adsorption, high-adsorption hemofiltration, and high-cutoff hemofiltration/hemodialysis. Promising results have been reported with all of these blood purification therapies, showing that they are well tolerated, effective in clearing inflammatory mediators or bacterial toxins (or both) from the plasma, and efficacious for improvement of various physiologic outcomes (for example, hemodynamics and oxygenation). However, numerous questions, including the timing, duration, and frequency of these therapies in the clinical setting, remain unanswered. Large multicenter trials evaluating the ability of these therapies to improve clinical outcomes (that is, mortality or organ failure), rather than surrogate markers such as plasma mediator clearance or transient improvement in physiologic variables, are required to define the precise role of blood purification in the management of sepsis.