Effects of Coupled Plasma Filtration Adsorption on Septic Patients with Multiple Organ Dysfunction Syndrome

Abstract

Aim: The aim of this study was to observe the effects of coupled plasma filtration adsorption (CPFA) on septic patients with multiple organ dysfunction syndrome (MODS). Methods: A total of 14 patients were randomly divided into two groups, and, respectively, received 10 h of CPFA or high-volume hemofiltration (HVHF). The mean arterial pressure (MAP), electrolytes and acid–base balance, the sequential organ failure assessment (SOFA) score, and the acute physiology and chronic health evaluation II (APACHE II) score were analyzed. Serum levels of high-mobility group box-1 (HMGB-1) protein, tumor necrosis factor-α (TNF-α), and intercellular adhesion molecule-1 (ICAM-1) were also measured by enzyme-linked immunosorbent assay. Results: After CPFA and HVHF, temporary reduction in blood urea nitrogen and serum creatinine, electrolytes and acid–base metabolism balance were well maintained. Both the SOFA and the APACHE II scores were markedly reduced after CPFA (p < 0.01), while only the SOFA score was significantly decreased after HVHF (p < 0.05). After 10-h treatment with CPFA, the MAP and oxygen index (PaO₂/FiO₂) were significantly higher than those at 0 h. Furthermore, the serum levels of HMGB-1, ICAM-1, and TNF-α decreased after 10 h of CPFA (p < 0.05), while the serum levels of HMGB-1 declined at 5 h of HVHF, but rebounded at 10 h, and the serum levels of TNF-α and ICAM-1 were no significant change after treatment with HVHF. Conclusions: The study indicated that CPFA could be superior to HVHF in improving the clinical manifestations and eliminating inflammatory mediators, which had implications in the optimal treatment of septic patients with MODS.

• high-volume hemofiltration
• coupled plasma filtration adsorption
• multiple organ dysfunction syndromes
• sepsis
• inflammatory mediators

INTRODUCTION

Severe sepsis represents the leading cause of mortality and morbidity in critically ill patients worldwide. The sepsis syndrome is associated with an overwhelming, systemic overflow of proinflammatory and anti-inflammatory mediators, which leads to generalized endothelial damage, multiple organ failure, and altered cellular immunological responsiveness.¹ Defined as a “systemic inflammatory response syndrome” (SIRS),^2,3 human sepsis is characterized by widespread endothelial damage caused by persistent inflammation resulting from infectious and noninfectious stimuli. Evidence has been accumulated that severe bacterial infections and septic shock are associated with increased levels of plasma cytokines such as tumor necrosis factor-α (TNF-α) and interleukins (IL)-1.⁴ These inflammatory mediators are important for the antimicrobial response to local body; however, excessive release of the body and overproduction lead to the diffuse tissue injury and multiple organ dysfunction.

In recent years, continuous renal replacement therapy (CRRT) ⁵ has opened the door to the wider application of blood purification technology in the critically ill patients. Several blood purification techniques, for example, continuous hemofiltration, high-volume hemofiltration (HVHF), and plasma exchange, had been proposed.^6,7 These technologies of dialysis were sought to increase the ultrafiltration rates to heighten the efficiency of clearance and they had been shown to improve hemodynamics, and might raise survival rate in septic patients, even in hemodynamic instability patients,^8–11 but such techniques appear to have theoretical as well as practical limitations. In order to achieve higher mediator clearances and mass removal rates, sorbent technologies were intensely studied and Tetta et al.¹² proposed coupled plasma filtration adsorption (CPFA). It is an adsorptive hemopurification method aimed for nonselective removal of circulating soluble mediators potentially involved in the pathogenesis of sepsis and septic shock. CPFA couples plasma filtration and adsorption on a resin cartridge, along with a second hemofiltration or hemodialysis. The nonselective removal of inflammatory mediators is achieved by hydrophobic styrene resin, which has high affinity and capacity for many cytokines and mediators.¹³ Therefore, we performed a study to test the hypothesis that CPFA may be superior to remove these inflammatory mediators and the clinical responses of the septic patients with multiple organ dysfunction syndrome (MODS).

PATIENTS AND METHODS

Patients

Fourteen patients were enrolled in the study and the inclusion criteria were (1) the presence of MODS and sepsis according to the ACCP/SCCM¹⁴ and the MODS diagnostic criteria promoted by the Academic Meeting of Critical Care Medicine in China; (2) the presence of acute kidney injury (AKI) determined by the evaluation of serum creatinine or urinary output; (3) 18–80 years old; and (4) hemodynamic instability requiring norepinephrine infusion. The exclusion criteria were with absolute contraindications for extracorporeal treatment, imminent death, or lack of consent. All patients were continuously monitored for heartbeat rate, respiration rate, mean arterial pressure (MAP), and oxygen saturation. The acute physiology and chronic health evaluation II (APACHE II) score and the sequential organ failure assessment (SOFA) score were used to assess the severity of illness and predicted mortality.

Dialysis Technique

A total of 14 patients were randomly divided into HVHF or CPFA group. Each group included seven patients. In the foundation of conventional therapy, the two groups were assigned to 10 h of HVHF or CPFA. HVHF was performed with the Baxter Aquarius (Baxter Healthcare Corporation, Deerfield, IL, USA) or ACH-10 (Asahi Kasei Corporation, formerly Asahi Chemical Industry Co., Ltd., Tokyo, Japan) CRRT machine, AV600 polysulfone filter (1.4 m², Fresenius Medical Care, Bad Homburg, Germany). The flow rate of exchange fluid was 6 L/h. The reinfusion fluid composition were sodium 140 mmol/L, potassium 2.0–3.0 mmol/L (regulated according to the electrolytes results before and during the treatment), and calcium 1.5–1.75 mmol/L (regulated according to the electrolytes results before and during the treatment), magnesium 0.5 mmol/L, chlorine 103 mmol/L, bicarbonate 35 mmol/L, and acetate 4 mmol/L. CPFA was also performed with the ACH-10 or Baxter Aquarius CRRT machine, a polypropylene plasma filter (PF2000N, 0.35 m², Gambro AB, Stockholm, Sweden) placed in series with a polysulfone hemodialyzer (F6, 1.3 m², Fresenius Medical Care) and an adsorbent cartridge (HA-330I, Zhuhai Lizhu Group, Biological Material Co, Ltd., Guangdong, China). The plasma filtration rate was 30–40 mL/min and the dialysis fluid rate was 2 L/h. The dialysis fluid compositions were sodium 140 mmol/L, potassium 2.0–3.0 mmol/L (regulated according to the levels of electrolytes before and during the treatment), calcium 1.5 mmol/L, magnesium 0.5 mmol/L, chlorine 103 mmol/L, bicarbonate 35 mmol/L, and acetate 4 mmol/L. The adsorption cartridge was changed for every 5 h.

A double lumen venous catheter was used to establish vascular access via the femoral or jugular veins. Blood flow rate was set at 180–200 mL/min. Low-molecular-weight heparin was administered according to the coagulation parameters and the ultrafiltration rate depended on the water balance. Heparin-free procedure was performed with normal saline flushing at 15 min intervals in active bleeding cases.

Detection of Blood Chemistry and Cytokines

The levels of hematocrit, plasma urea nitrogen, creatinine, sodium, potassium, and calcium, which derived from venous blood, were analyzed before and after therapies. Hydrogen ion concentration, carbonic acid hydrogen radical density, and oxygen partial pressure were detected through arterial blood gas analysis, and the Oxygen index was calculated.

Serum levels of high-mobility group box-1 (HMGB-1), TNF-α, and intercellular adhesion molecule-1 (ICAM-1) were assigned to measure by enzyme-linked immunosorbent assay (ELISA), strictly according to the manufacturer’s instructions. HMGB-1 and ICAM-1 ELISA kits were purchased from Uscn Life Science & Technology Company (USA). TNF-α ELISA kits were obtained from R&D Systems Inc. (USA).

Statistical Analysis

All data are presented as mean ± standard deviation and analyzed by SPSS 15.0 statistical software. Statistical evaluation was performed by Student’s t-test. All cytokine data were analyzed by one-way analysis of variance (ANOVA). A p-value <0.05 was considered statistically significant.

RESULTS

Clinical Effects

The clinical baseline of the two groups was essentially similar: the female were enrolled in each group, the ages were 61 ± 15.9 years versus 64.6 ± 25.7 years (p > 0.05) and the number of failure organs was 2.5 ± 0.5 versus 2.4 ± 0.5 (p > 0.05) for the HVHF and CPFA groups, respectively.

The heartbeat rates (HRs) were 99.29 ± 7.74/min and 104.2 ± 10.11/min in the HVHF group and the CPFA group, respectively, before treatment, and they were remarkably decreased to 80.00 ± 7.81/min in the HVHF group and 85.00 ± 4.00/min in the CPFA groups after 10-h treatment. The MAP were significantly elevated from 79.20 ± 13.14 to 96.00 ± 13.84 mmHg after 10-h treatment of CPFA and the requirement of dopamine was 4.26 ± 4.19 versus 1.17 ± 1.51 μg/kg/min (p < 0.01). While no significant change of the MAP was seen after 10-h treatment of HVHF (p > 0.05) and the dopamine requirement was 4.17 ± 4.12 versus 2.73 ± 3.48 μg/kg/min (p > 0.05). In addition, the SOFA score was remarkably reduced (p < 0.05), and there were no significant differences in the APACHE II score after 10-h treatment of HVHF. However, both the SOFA score and the APACHE II score decreased dramatically (p < 0.01) at 10 h of CPFA (Table 1).

Table 1.  Physiological variables before and after HVHF and CPFA.

	HVHF (n = 7)			CPFA (n = 7)
	0 h	10 h	pa	0 h	10 h	pb
HR (/min)	99.29 ± 7.74	80.00 ± 7.81**	<0.01	104.2 ± 10.11	85.00 ± 4.00*	<0.05
MAP (mmHg)	80.29 ± 7.06	88.57 ± 9.73	>0.05	79.20 ± 13.14	96.00 ± 13.84**	<0.01
Dopamine (μg/kg/min)	4.17 ± 4.12	2.73 ± 3.48	>0.05	4.26 ± 4.19	1.17 ± 1.51**	<0.01
SOFA	14.57 ± 3.10	10.71 ± 2.22*	<0.05	12.60 ± 1.82	7.00 ± 1.41**	<0.01
APACHE II	24.29 ± 6.47	19.43 ± 5.32	>0.05	26.20 ± 5.36	14.20 ± 2.78**	<0.01

Notes: *p < 0.05, **p < 0.01, p_a: 0 h versus 10 h in HVHF group, p_b: 0 h versus 10 h in the CPFA group.

HR, heart rate; MAP, mean arterial pressure; SOFA, sepsis-related organ failure assessment score; APACHE II, acute physiology and chronic health evaluation II; CPFA, coupled plasma filtration adsorption; HVHF, high-volume hemofiltration.

As expected, the levels of blood urea nitrogen (BUN) and serum creatinine (SCr), both significantly decreased with the two therapies (p < 0.01), and electrolytes and acid–base balance were well maintained (Table 2). However, the oxygenation index (PaO₂/FiO₂) showed significant improvement (p < 0.01) in the CPFA group, and no significant change was seen in the HVHF group (Table 3). The pH, , and base excess (BE) were in approximately normal range in both the groups before treatment; therefore, there were no significant changes in the above parameters in both the groups after treatment. Furthermore, no therapy-related adverse reactions, including severe hemorrhage, shock, and hypersensitivity, were noted.

Table 2.  Laboratory variables before and after HVHF and CPFA.

	HVHF (n = 7)			CPFA (n = 7)
	0 h	10 h	pa	0 h	10 h	pb
BUN (mmol/L)	40.59 ± 9.43	22.53 ± 9.97**	<0.01	33.20 ± 12.56	18.30 ± 9.43**	<0.01
SCr (μmol/L)	486.71 ± 173.1	276.57 ± 89.88**	<0.01	385.40 ± 133.5	129.40 ± 66.83*	<0.05
K^+ (mmol/L)	4.78 ± 0.92	3.61 ± 0.12**	<0.01	4.64 ± 0.82	3.70 ± 0.13*	<0.05
Na^+ (mmol/L)	140.75 ± 7.37	139.48 ± 5.13	>0.05	142.67 ± 9.56	142.74 ± 6.86	>0.05
Ca^2+ (mmol/L)	2.12 ± 0.18	2.22 ± 0.13	>0.05	2.08 ± 0.29	2.23 ± 0.15	>0.05

Notes: *p < 0.05, **p < 0.01, p_a: 0 h versus 10 h in the HVHF group, p_b: 0 h versus 10 h in the CPFA group.

BUN, blood urea nitrogen; SCr, serum creatinine; Na⁺, sodium; K⁺, potassium; Ca²⁺, calcium.

Table 3.  Changes of blood gas analysis before and after HVHF and CPFA.

	HVHF (n = 7)			CPFA (n = 7)
	0 h	10 h	pa	0 h	10 h	pb
PH	7.35 ± 0.04	7.35 ± 0.03	>0.05	7.47 ± 0.06	7.42 ± 0.04	>0.05
(mmol/L)	22.16 ± 7.55	23.27 ± 4.18	>0.05	21.31 ± 7.74	23.52 ± 2.31	>0.05
BE (mmol/L)	−1.56 ± 5.27	2.47 ± 0.55	>0.05	−3.37 ± 6.27	1.45 ± 2.42	>0.05
PaO2/FiO2	192.43 ± 34.78	234.28 ± 46.60	>0.05	187.80 ± 58.33	297.40 ± 37.87**	<0.01

Notes: *p < 0.05, **p < 0.01, p_a: 0 h versus 10 h in the HVHF group, p_b: 0 h versus 10 h in the CPFA group.

PH, hydrogen ion concentration; , bicarbonate; BE, base excess; PaO₂/FiO₂, oxygen arterial pressure.

Table 4.  Changes of serum levels before and after HVHF and CPFA.

	HVHF (n = 7)					CPFA (n = 7)
	0 h	5 h	pa	10 h	pb	0 h	5 h	pc	10 h	pd
HMGB-1 (ng/mL)	29.30 ± 7.73	21.38 ± 6.32*	<0.05	25.60 ± 4.24	>0.05	27.03 ± 6.25	18.26 ± 5.93*	<0.05	16.58 ± 6.26**	<0.01
ICAM-1 (ng/mL)	708.06 ± 98.27	614.75 ± 41.64	>0.05	675.64 ± 44.36	>0.05	798.17 ± 134.12	610.33 ± 116.74	>0.05	347.61 ± 181.53**	<0.01
TNF-α (pg/mL)	177.99 ± 57.71	175.46 ± 49.83	>0.05	186.87 ± 55.09	>0.05	229.82 ± 77.89	183.51 ± 44.24	>0.05	151.78 ± 29.45*	<0.05

Note: *p < 0.05, **p < 0.01, p_a: 0 h versus 5 h in the HVHF group, p_b: 0 h versus 10 h in the HVHF group, p_c: 0 h versus 5 h in the CPFA group, p_d: 0 h versus 10 h in the CPFA group.

Serum Cytokine Levels

Before treatment, there were no significant difference of the serum levels of TNF-α, ICAM-1, and HMGB-1 between the HVHF and the CPFA groups. However, in the CPFA group, the serum levels of HMGB-1, ICAM-1, and TNF-α declined remarkably after treatment. Interestingly, the serum levels of HMGB-1 were decreased only at 5-h posttreatment (p < 0.05) and were rebounded to original levels at 10-h posttreatment. In addition, there were no remarked changes of the serum levels of ICAM-1 and TNF-α during the HVHF treatment (Table 4).

DISCUSSION

Severe sepsis and septic shock are the reasons leading to MODS and mortality in intensive care units. Although many advances have been made in the understanding of the complex biological mechanisms, there has been no definite therapy that can successfully treat sepsis and its complications yet. Currently, blood purification remains one of the indispensable means of the treatment of MODS. Therapies targeting the specific components of the sepsis pathological cascade have been attempted in recent years, but we have not obtained so effective outcomes. In some human studies, de Vriese et al.¹⁵ had shown that most removal was by adsorption when conventional membranes were used. Such adsorptive effect was rapidly exhausted. Thus, it appeared that conventional CRRT might be inadequate in patients with sepsis because of the limited intensity of plasma water exchange and/or the limited pore size of the filters in current use. CPFA, a new type of continuous blood purification, combines a variety of mechanisms of blood purification therapy, and in particular reinforces, the adsorption mechanism shows a good prospect in the treatment of MODS. CPFA was developed as an adsorptive hemopurification method aimed for nonselective removal of circulating soluble mediators potentially involved in the pathogenesis of sepsis.¹⁶ It is a technique that separates plasma from blood by means of a plasma filter. The plasma is then passed through a synthetic resin cartridge and returned to the blood. A second blood filter can be then used to remove excess fluid and low-molecular-weight toxins.¹⁷ The removal of cytokines may be remarkably enhanced and the clinical manifestations could be improved using CPFA.

In our present study, it showed that the efficacy as measured by hemodynamic effect was remarkable with a significant decrease in HR and a significant increase in MAP in the CPFA group. On the contrary, in the CPFA group, the improvement of APACHE II score and SOFA score were better than those in the HVHF group. APACHE II score, according to patients with acute physiology and chronic health evaluation parameters severity, can accurately assess the condition and predict mortality in critically ill patients, which has a better calibration of degrees, while SOFA score is only to reflect the degree of organ failure in septic patients and to evaluate the treatment effect on organ function. In our study, the APACHE II score and SOFA score at 10th hour after CPFA treatment were significantly lower than those at 0 h, while there was remarked declined in APACHE II score after 10-h HVHF treatment. And similar to the HVHF treatment group, the CPFA treatment group could also maintain a well water, electrolyte, and acid–base balance, lower the levels of BUN and SCr, which could improve renal function. The study did not appear treatment-related adverse complications, particularly in patients with no significant decrease in platelet counts after CPFA treatment. Although the absorber device was introduced, blood cells do not contact with the adsorbed directly and avoid the general side effects seen in thrombocytopenia. Compared with the HVHF group, there was also a significant improvement in PaO₂/FiO₂ in the CPFA group, which illustrated the better improvement of the lung function. Besides, CPFA could remove mediators much more efficiently with the characteristic of higher selection coefficient. HMGB-1, ICAM-1, and TNF-α were analyzed in our experiment. As a late mediator, HMGB-1 is secreted by neutrophils and monocytes and released extracellularly from damaged and necrotic cells.^18–24 Elevated serum HMGB-1 levels have been observed in patients with septic shock, with the highest levels observed in nonsurvivors,²³ and Sakamoto et al.²⁴ showed that the circulation dynamics of patients with septic shock could be improved by reducing HMGB-1 level. In addition, increased expression of ICAM-1 and TNF-α has been observed in sepsis and SIRS.²⁵ ICAM-1 deficient mice was found to be protected from experimental sepsis-induced AKI,²⁶ which was a frequent complication occurring in sepsis or septic shock.^27,28 Vincenzo Cantaluppi et al.²⁹ recently found that ICAM-1 could be removed by resin Amberchrom CG161M adsorption efficiently and reduced a consequent limitation of septic plasma-induced tubular injury in vitro. TNF-α, which is an important factor causing tissue damage, participates in the startup process of systemic inflammatory cascade response, plays an important role in the high metabolic state of posttraumatic and activates the complement system and coagulation system. The molecular weights of ICAM-1 (79–114 kDa) and TNF-α (54 kDa) were higher than the pore size of AV600 polysulfone membrane we used. In our study, we found the following results. In the CPFA group, serum inflammatory mediators HMGB-1, ICAM-1, and TNF-α were all effectively cleaned. However, in the HVHF group, there was a significant decline in the level of HMGB-1 at 5 h, but it did not continued at the period of 10 h, and there were no significant changes in the serum levels of ICAM-1 and TNF-α. This demonstrated that on the basis of HVHF and combined with plasmapheresis or plasma-adsorption, CPFA enhanced the ability of adsorption and could effectively eliminate the mediators. So the adsorption-based elimination was considered to be the main clearance effect. In addition, no therapy-related adverse reactions were found, so that the CPFA therapy could be proved safe and feasible.

These evidences indicated that CPFA had a better impact on hemodynamics and might reduce the “peak effective concentration” of different mediators more effectively than HVHF. Therefore, CPFA might be better than HVHF treatment on MODS and organ failure in septic patients. And this revealed that CPFA had implications in the optimal treatment of septic patients with MODS.

ACKNOWLEDGMENTS

This work was supported by Children’s Miracle Network Awards 2005–2010, Project supported by the Scientific Research Foundation of the State Human Resource Ministry for Selected Returned Overseas Chinese Scholars 2008-148, Project supported by the key lab of Jiangsu province MMB09KF04, Project supported by the Scientific Research Program of the Health Department of Jiangsu Province H200902 and XK16200903, Project supported by the National Natural Science Foundation of China H0511-81070588, Project supported by the international cooperation projects of Jiangsu province BZ2010058 and Project supported by the funding of blue project 2010.