Does an Early Implantation of Extracorporeal Membrane Oxygenator in High-Risk Emergency Open Heart Surgery Patients Improve the Outcome in Comparison with Elective Patients? A Prospective Cohort Comparative Study.

BACKGROUND: Extracorporeal membrane oxygenator (ECMO) has been implemented in refractory postcardiotomy cardiogenic shock (PCCS) patients to maintain excellent oxygenation and hemodynamic support. The aim of this study is to compare the results of early ECMO implantation to treat refractory PCCS in emergency versus elective patients who developed univentricular or biventricular pump failure. PATIENTS AND METHODS: Between January 2019 and June 2021, 35 patients received ECMO after refractory PCCS. Patients have been categorized into two groups: Group A contains 18 patients who were urgently operated on and Group B, which includes 17 patients who were electively operated on. ECMO was implanted through central cannulation (right atrium and ascending aorta), or through peripheral cannulation (femoral vessels or through axillary artery). RESULTS: There was no statistically significant difference between the two ECMO groups in the preoperative patient's characteristics, complication rate, duration of mechanical ventilation, post-ECMO weaning hospital stay, duration of ICU stay, in-hospital mortality, and number of patients discharged from the hospital or in 1-year survival on follow up. CONCLUSION: Early use of ECMO in high-risk emergency cardiac surgery should be taken into consideration when possible, without hesitance. Emergency and elective patients benefit equally from ECMO implantation and show comparable complication rates.

Technical Indicators to Evaluate the Degree of Large Clot Formation Inside the Membrane Fiber Bundle of an Oxygenator in an In Vitro Setup.

The most common technical complication during ECMO is clot formation. A large clot inside a membrane oxygenator reduces effective membrane surface area and therefore gas transfer capabilities, and restricts blood flow through the device, resulting in an increased membrane oxygenator pressure drop (dpMO). The reasons for thrombotic events are manifold and highly patient specific. Thrombus formation inside the oxygenator during ECMO is usually unpredictable and remains an unsolved problem. Clot sizes and positions are well documented in literature for the Maquet Quadrox-i Adult oxygenator based on CT data extracted from devices after patient treatment. Based on this data, the present study was designed to investigate the effects of large clots on purely technical parameters, for example, dpMO and gas transfer. Therefore, medical grade silicone was injected into the fiber bundle of the devices to replicate large clot positions and sizes. A total of six devices were tested in vitro with silicone clot volumes of 0, 30, 40, 50, 65, and 85 mL in accordance with ISO 7199. Gas transfer was measured by sampling blood pre and post device, as well as by sampling the exhaust gas at the devices' outlet at blood flow rates of 0.5, 2.5, and 5.0 L/min. Pre and post device pressure was monitored to calculate the dpMO at the different blood flow rates. The dpMO was found to be a reliable parameter to indicate a large clot only in already advanced "clotting stages." The CO2 concentration in the exhaust gas, however, was found to be sensitive to even small clot sizes and at low blood flows. Exhaust gas CO2 concentration can be monitored continuously and without any risks for the patient during ECMO therapy to provide additional information on the endurance of the oxygenator. This may help detect a clot formation and growth inside a membrane oxygenator during ECMO even if the increase in dpMO remains moderate.

Humoral immune response and coated or uncoated oxygenators during cardiopulmonary bypass surgery.

AIM: To investigate and compare uncoated and phosphorylcholine-coated oxygenators in terms of induction of humoral immune response during coronary artery bypass surgery. METHODS: A total of 20 consecutive patients who underwent coronary artery bypass surgery were randomly distributed into two groups according to the type of oxygenator used during surgery. Group 1 consisted of 10 patients who were operated on using phosphorylcholine-coated oxygenators. Group 2 contained 10 patients who underwent surgery using uncoated oxygenators. Blood and oxygenator fibre samples were obtained and compared in terms of immunoglobulins (IgG, IgM), complements (C3c, C4), serum total protein and albumin levels using electron microscopy and flow cytometry. RESULTS: In group 1, levels of IgM, IgG, total protein and serum albumin were significantly increased at the end of cardiopulmonary bypass (CPB) compared to those at the beginning of CPB. In group 2, C3c and C4 levels at the beginning of CPB were found to be significantly higher than at the end. Electron microscopic examination of oxygenator fibres demonstrated that phosphorylcholine-coated fibres were less likely to be adsorbed by serum proteins and complements than the uncoated fibres. CONCLUSION: Our results indicate that phosphorylcholine-coated oxygenators seemed to induce humoral immune response to a lesser extent than uncoated oxygenators during coronary artery bypass procedures.

An Alternative Approach for Perioperative Extracorporeal Life Support Implantation.

Central veno-arterial extracorporeal membrane oxygenation (ECMO) is traditionally implanted using direct cannulation of the aorta and right atrium. We aim to summarize the outcome of patients who underwent perioperative central ECMO implantation using an alternative surgical approach, which allows sternum closure and does not require resternotomy at the time of explantation. We retrospectively reviewed patients who required veno-arterial ECMO support at our institution between January 2013 and July 2014. Inclusion criteria were patients undergoing central ECMO implantation using the above-mentioned implantation technique. Nine patients (65 ± 14 years) were supported using this technique. Four patients underwent coronary bypass surgery as a primary surgery and the other five patients had combined coronary and valve surgeries. The average duration of ECMO support was 9 ± 7 days (range 1-24 days). The dominant postoperative complication was renal failure, which occurred in eight patients (89%). In four patients (44%), the ECMO was successfully removed. Survival rate to discharge was 22%. In conclusion, this study showed the feasibility of this alternative ECMO implantation technique. No technical issues were encountered. Extended support duration and reducing resternotomy risks may be the main advantages of this technique compared with conventional ECMO implantation methods.

Influence of different oxygenator types on changing frequency, infection incidence, and mortality in ARDS patients on veno-venous ECMO.

PURPOSE: Veno-venous extracorporeal membrane oxygenation (vv-ECMO) is pivotal in the treatment of patients suffering from acute respiratory distress syndrome (ARDS). Comparative data with different oxygenator models have not yet been reported. The aim of this retrospective investigation was therefore to assess whether different oxygenator types might influence changing frequency, infection incidence, and mortality in patients on vv-ECMO. METHODS: 42 patients undergoing vv-ECMO between 1998 and 2009 were identified. In 20 out of these patients, a polypropylene (PP) microporous hollow fiber membrane oxygenator, and in 22 patients a nonmicroporous polymethylpentene (PMP) diffusion membrane oxygenator was used. Infection incidence, changing frequency, and mortality were documented. RESULTS: In the PMP group, an oxygenator change was necessary less often than in the PP group (p<0.001). The incidence of bacterial, viral, or fungal growth was similar in the groups, thus independent of the frequency of oxygenator change. Irrespective of the groups, the occurrence of Candida sp. tended to correlate with death (p = 0.06). In general, there was a trend towards a higher infection incidence in the subgroup with pulmonary ARDS (p = 0.07). Moreover, infection incidence was associated with a longer ICU stay (p = 0.03) and longer ECMO therapy (p = 0.03). ICU mortality was lower in the PMP group than in the PP group, although not statistically significant (p = 0.10). CONCLUSIONS: The PMP oxygenator membranes showed benefits with regards to changing frequency, but not infection incidence, length of ICU stay, and length of ECMO therapy. There was a trend towards a lower ICU mortality in patients with PMP oxygenators.

[Factors of intravascular hemolysis in cardiosurgical patients after cardiopulmonary bypass procedures].

The study included patients with ischemic heart disease with moderate (52 patients) and apparent (23 patients) hemolysis after coronary bypass surgery in cardiopulmonary bypass (CB). The concentration of free hemoglobin in blood plasma, mechanical resistance and sorption capacity of red cells as well as the content of TBA-active products, cholesterol and phospholipids in red cells and reticulocytes levels in blood were studied before and after operation. It was shown that among patients with apparent post-perfusion hemolysis (in contrast to the patients with a moderate hemolysis) the sorption capacity of red cells and amount of reticulocytes in blood are increased before operation; level of TBA-active products in erythrocytes is increasing after operation. Development of moderate hemolysis is associated with the decreased mechanical resistance of erythrocytes and increased cholesterol/phospholipid-ratio in membranes before operation. Thus, individually-specified apparent post-perfusion hemolysis is based on free-radical mechanism of erythrocytes damage and moderate hemoglobin level is referred to mechanical trauma of blood cells during CB.

[Oxygenator thrombosis without heparin resistance in polycythemia vera]. / Thrombose d'oxygénateur en l'absence de résistance à l'héparine mais en présence d'une maladie de Vaquez.

A 55-year-old male with a history of positive HIV serology and polycythemia vera underwent coronary artery bypass graft surgery with normothermic extracorporeal circulation. Following heparin administration the activated clotting time (ACT) was 633 seconds (Hemocron with kaolin). Lower than expected arterial and venous oxygen partial pressures together with high pressure (350 mmHg) in the arterial line upstream of the oxygenator were observed. Because of these signs the oxygenator was changed during the procedure. The outcome was uneventful. Electronic microscopic examination of the oxygenator membrane and thermic exchanger revealed fibrin and platelet deposits. Similar cases are described in the literature during polycythemia vera. Therefore the prevention might be a preoperative treatment with antiplatelet therapy in polycytemia vera.

Impact of preoperative percutaneous cardiopulmonary support on outcome following left ventricular assist device implantation.

BACKGROUND: The purpose of the present study was to determine the impact of preoperative percutaneous cardiopulmonary support (PCPS) on long-term survival following implantation of a left ventricular assist device (LVAD). METHODS AND RESULTS: Between 1999 and 2010, we used implantable (n=12) and paracorporeal (n=91) LVADs in 103 consecutive cardiomyopathy patients as a bridge to transplantation. Prior to LVAD implantation, all patients received inotropes, and 25 patients (24%) received PCPS because of cardiogenic shock. Postoperatively, there were no early mortalities within 30 days after surgery, and patients survived on LVAD for 560±391 days, of whom 9 patients recovered and 32 underwent heart transplantation after 711±360 days of LVAD support. More patients with preoperative PCPS required nitric oxide inhalation and prolonged inotropic support to maintain adequate LVAD flow. In addition, bilirubin level at 1 month after LVAD implantation was significantly higher in patients with preoperative PCPS. Cox regression analysis identified preoperative PCPS support as the only significant predictor for death after LVAD implantation and overall survival was significantly better in patients without preoperative PCPS. CONCLUSIONS: Despite adequate hemodynamic support after LVAD implantation, patients with preoperative PCPS had significantly worse survival. LVAD should be used for patients with end-stage heart failure, before PCPS is required for hemodynamic support.

Avecor Trillium oxygenator versus noncoated Monolyth oxygenator: a prospective randomized controlled study.

OBJECTIVES: The surface coating of a synthetic surface is currently investigated to decrease the harmful effects of cardiopulmonary bypass (CPB). This study was designed to study the effects of the surface coating of a hollow fiber membrane oxygenator on coagulation, inflammation markers, and clinical outcomes. The biomaterials used to coat the membrane include heparin, polyethylene oxide chains (PEO), and sulfate/sulfonate groups. The coated membrane was compared to an uncoated oxygenator made of polypropylene. METHODS: Two hundred patients who were scheduled to undergo valve repair and/or replacement surgery with or without coronary surgery were enrolled in the study. The patients were randomized to undergo CPB with either the Avecor oxygenator with Trillium (Medtronic, Minneapolis, MN, USA), a biopassive surface, or the Monolyth (Sorin, Irvine, CA, USA) oxygenator without coating. The primary and secondary endpoints were the differences between these oxygenators in regard to patients' biochemistry, coagulation profiles, inflammatory mediators, and clinical outcomes, including blood loss and neurological events. RESULTS: There were no differences between the two groups in terms of biochemistry, coagulation profile, inflammatory mediator release, and blood loss. Five patients in the Avecor group showed clinical evidence of a stroke confirmed with computerized tomography (CT) scan imaging, and none in the noncoated oxygenator group. CONCLUSION: The oxygenator Avecor offers similar results in terms of inflammation and coagulation profiles and blood loss during valvular surgery compared to a standard uncoated control oxygenator. The rate of neurological events was unusually elevated in the former group of patients, with only speculative explanation at this point. Further studies are warranted to clarify this aspect.

Effect of biopassive and bioactive surface-coatings on the hemocompatibility of membrane oxygenators.

Postoperative complications associated with cardiopulmonary bypass (CPB) surgery and extracorporeal circulation (ECC) procedures are still a major clinical issue. Improving the hemocompatibility of blood contacting devices used for ECC procedures may ameliorate various postpump syndromes. In a simulated CPB model using human blood, we investigated the hemocompatibility, fibrinogen adsorption, and platelet receptor (GPIIb-IIIa) binding capacity of surface-modified membrane oxygenators (Jostra Quadrox). Three groups were compared: (i) biopassive protein coatings (SafeLine), (ii) bioactive heparin coatings (BioLine), and (iii) noncoated controls. During the 2 h recirculation period, plasma concentrations of activation markers for platelets (beta-thromboglobulin), inflammation (elastase), complement (C5a), and coagulation (prothrombin fragment 1+2, thrombin-antithrombin III) were lower in the groups with biopassive and bioactive coatings compared to the noncoated group (p < 0.01). These parameters did not significantly differ between the two surface-coated groups, except for complement activation: C5a levels were higher in the biopassive group compared to the bioactive group (p < 0.01). Moreover, surface-coated oxygenators showed less fibrinogen adsorption, GPIIb-IIIa binding, and platelet/leukocyte adhesion (p < 0.01). We assume that fewer fibrinogen and platelet receptor molecules bound to the surface-coated oxygenator surfaces results in fewer platelet adhesion and activation, which will significantly contribute to the improved hemocompatibility of the biopassive and bioactive oxygenators. Our results suggest that the application of bioactive oxygenators (BioLine) during CPB surgery may reduce postoperative complications for the patient more effectively than biopassive oxygenators (SafeLine).

Evaluation of coated oxygenators in cardiopulmonary-bypass systems and their impact on neurocognitive function.

INTRODUCTION: Coronary artery bypass graft surgery (CABG) using cardiopulmonary bypass (CPB) is assumed to be associated with a decline of neurocognitive functions. This study was designed to analyse the neurocognitive function of patients with coronary heart disease before and after CABG and to determine possible protective effects of oxygenator surface coating on neurological outcome. METHODS: Forty patients scheduled for selective CABG were prospectively randomized into two groups of 20 patients each according to the type of hollow-fibre membrane oxygenator used. Non-coated oxygenators (Group A) were compared to phosphorylcholine (PC)coated oxygenators (Group B). A battery of six neurological tests was administered preoperatively, 7-10 days and 4-6 months after surgery. RESULTS: One patient of Group A suffered from a perioperative stroke and died on postoperative day 3, presumably because of sudden heart failure. Two patients of Group A (10%) developed a symptomatic transitory delirious psychotic syndrome (STPT) on postoperative days 3 and 5. None of the patients of Group B had perioperative complications. The test analysis revealed a trend of declined neurocognitive function early after CABG, but did not show any difference in neurocognitive outcome between the two groups. DISCUSSION: PC coating of the oxygenators did not show any significant benefit on neurocognitive function after CABG using CPB.

Comparison of hollow-fiber membrane oxygenators in terms of pressure drop of the membranes during normothermic and hypothermic cardiopulmonary bypass in neonates.

UNLABELLED: The objective of this study was to investigate the effects of two hollow-fiber membrane oxygenators, the Capiox SX10 and the Lilliput 901, on pressure drop of the membranes during normothermic and hypothermic cardiopulmonary bypass (CPB) in neonates. METHODS: Twenty-six congenital heart surgery patients (n = 13 in each group) with a mean weight of 3 kg were included in this study. Pressure drops of the membranes, pre- and post-oxygenator extracorporeal circuit pressures (ECC) were recorded during normothermic CPB, hypothermic CPB (20 degrees C) and after rewarming. There were no differences between the groups in mean arterial pressure, pump flow rate, temperature, duration of CPB, crossclamp time or the severity of the surgical repairs. RESULTS: Pressure drop of the Capiox SX10 oxygenator was significantly lower during normothermic (32 +/- 10 versus 55 +/- 16 mmHg, p < 0.001), hypothermic (38 +/- 15 versus 72 +/- 18 mmHg, p < 0.001) and post-rewarming (42 +/- 13 versus 72 +/- 21 mmHg, p < 0.001) periods compared to the Lilliput oxygenator. In the Capiox group, the pre-oxygenator ECC pressure was also significantly lower during normothermic CPB (142 +/- 27 versus 184 +/- 43 mmHg, p < 0.01), hypothermic CPB (162 +/- 30 versus 199 +/- 38 mmHg, p < 0.01) and after rewarming periods (172 +/- 32 versus 212 +/- 42 mmHg, p < 0.01). Post-oxygenator pressures in the Capiox group were also lower than in the Lilliput group, but results were not statistically significant. CONCLUSIONS: These results suggest that the Capiox SX10 hollow-fiber membrane oxygenator produced significantly lower membrane pressure drops and pre- and post-oxygenator ECC during normothermic and hypothermic CPB. Thus, blood trauma with the Capiox during extracorporeal circulation may be significantly lower compared to the Lilliput. Further studies, including the level of complements, platelets, neutrophils and cytokines, with these oxygenators are warranted.

[Oxygenator thrombosis without heparin resistance]. / Thrombose d'oxygénateur en l'absence de résistance à l'héparine.

A 55-year-old male with a history of positive HIV serology and Polycytemia vera underwent coronary artery bypass graft surgery with normothermic extracorporeal circulation. Following heparin administration the activated clotting time (ACT) was 633 seconds (Hemocron) with kaolin). Lower than expected arterial and venous oxygen partial pressures together with high pressure (350 mmHg) in the arterial line upstream of the oxygenator were observed. Because of these signs the oxygenator was changed during the procedure. The outcome was uneventful. Electronic microscopic examination of the oxygenator membrane and thermic exchanger revealed fibrin and platelet deposits.

Doppler microembolic signals during cardiopulmonary bypass: comparison of two membrane oxygenators.

We undertook this study to evaluate the dependence of Doppler microembolic signal (MES) counts, detected during cardiopulmonary bypass, on the type of oxygenator used. A total of 90 patients, 71 men and 19 women, aged 60 +/- 10 years (mean +/- SD), undergoing elective cardiac surgery for coronary artery bypass grafting (one vessel, n = 6; two vessels, n = 24; three vessels, n = 33; four vessels, n = 9) or valve replacement (mitral valve, n = 2, aortic valve, n = 15, both valves, n = 1) were monitored with transcranial Doppler sonography during the complete surgical procedure. The surgical and anesthetic techniques were standardized in all patients, except for the type of membrane oxygenator used (COBE CML Duo, n = 55 or DIDECO D 703, n = 35). MES count was expressed as total number of MES detected in both middle cerebral arteries during cardiopulmonary bypass (CPB) and also as total MES number divided by the CPB duration in minutes (MES min(-1)). No significant differences in patients' age or sex and type and duration of operation were noted between the two groups. MES incidence while the patients were on cardiopulmonary bypass was 100%. MES counts during CPB were 309 (236-502) and 143 (86-233) for DIDECO and COBE oxygenators, respectively (p < 0.00001). MES min(-1) were also significantly higher in patients operated with DIDECO, as compared to COBE oxygenators (3.7 (2.4-5.6) versus 1.5 (1-2.4), respectively, p < 0.0001). Inter-observer variability was satisfactory (k = 0.72). Use of a DIDECO D 703 oxygenator resulted in significantly higher MES counts as compared to the COBE CML Duo oxygenator. The clinical relevance of this finding remains to be determined.

High risk of intraoperative awareness during cardiopulmonary bypass with isoflurane administration via diffusion membrane oxygenators.

In cardiac surgery with the aid of extracorporeal circulation (ECC), inhalation anaesthetics can be administered via the oxygenator. Until the recent advent of a new type of diffusion membrane oxygenator, we routinely added the inhalation agent, isoflurane, to the gas flow of a microporous capillary membrane-type oxygenator. Applying this procedure to the diffusion-type oxygenators, the depth of anaesthesia appeared to be affected, which manifested itself through unusually high intraoperative perfusion pressures. This observation led to a prospective randomized study comprising 60 patients and two models of a microporous capillary membrane oxygenator, as well as two models of a diffusion membrane oxygenator. Simultaneous isoflurane concentration measurements at both the gas inlet and outlet ports of the oxygenators showed that, whereas in the microporous capillary-type oxygenators the isoflurane administered was reduced by about 50% during the passage of gas through the device, there was only a minimal transfer of isoflurane in the diffusion-type membrane oxygenators.

Oxygenator thrombosis: worst case after development of an abnormal pressure gradient--incidence and pathway.

The development of an abnormally high pressure gradient (APG) before the membrane oxygenator (MO) is a complication that occurs during some extracorporeal circulation (ECC) procedures. The present study deals with the incidence of an APG and discusses a probable causative pathway by comparing surface-coated and uncoated oxygenation systems. Five thousand six hundred and seventeen adult ECCs were carried out (2,581 without and 3,036 with surface coatings). The incidence of an APG, therefore, amounted to 0.03% in the group with coated systems and 4.3% in the uncoated group. In addition, an in vitro study demonstrated significantly reduced adhesion and activation of platelets and leucocytes when the surfaces of the MOs were coated with heparin or polypeptides. The advantages of coating surfaces of ECC devices possibly depend on the selective adsorption of particular plasma proteins. These will presumably form a biocompatible membrane on the surface, and minimize pathological deposit of fibrin, platelets and other blood cells, and, therefore, implicate the prevention of an oxygenator failure.

Nitric oxide added to the sweep gas infusion reduces local clotting formation in adult blood oxygenators.

Nitric oxide (NO) is an inhibitor of platelet aggregation. We analyzed the effect of direct infusion of NO into adult blood oxygenators on local clot formation. Nonheparinized calves in a control group (n = 3) and NO group (n = 4) were connected to a jugulocarotid cardiopulmonary bypass (CPB; centrifugal pump) for 6 hours. The venous line and pumphead were heparin coated, whereas the oxygenator, the heat exchanger, and the arterial line were not. A total of 80 ppm of NO was mixed with the sweep gas infusion in the NO group. The pressure gradient through the oxygenator (deltaP.Ox.) was monitored, and its evolution was compared between groups. Oxygenators membranes were analyzed and photographed, allowing for calculation of the percentage of surface area covered with clots by using a computer image analysis program. The deltaP.Ox. reached a plateau of 193 +/- 26% of the basal value in the NO group after 120 minutes, whereas a similar plateau of 202 +/- 22% was reached after only 20 minutes in the control group (p < 0.05). The surface area of the oxygenator covered with clots was significantly reduced in the NO group (0.54 +/- 0.41%) compared with the control group (5.78 +/- 3.80%, p < 0.05). However, general coagulation parameters were not modified by local NO administration. The activated coagulation time remained stable between 110 and 150 seconds in both groups (p = not significant [ns]), and there were no differences in hematocrit, thrombin time, partial thromboplastin time, or fibrinogen between groups during the 6 hours of CPB. Thus, the mixed infusion of a continuous low dose of NO into adult oxygenators during prolonged CPB prevented local clot formation, whereas the general coagulation pattern remained unchanged.

Effect of surface coating on platelet count drop during cardiopulmonary bypass.

This study was designed to investigate the effect of surface coating on platelet count drop during cardiopulmonary bypass (CPB). Sixty patients undergoing open-heart surgery were randomly divided into three groups each receiving a different type of coated hollow-fiber membrane oxygenator. The patients were given either an uncoated oxygenator (noncoated group), an oxygenator coated with Carmeda (Carmeda group) or an uncoated oxygenator with albumin in the priming solution (albumin group). Comparisons were made in platelet count pre-CPB, on bypass (15-25 min) and during the warming period. Calculations were used to account for the effect of hemodilution. The albumin group had significantly lower platelet count drops (-4.8+/-7.1%) than the Carmeda group (11.0+/-8.3%) and the noncoated group (20.3+/-14.5%). Carmeda surface coating demonstrated some beneficial effects, but to a lesser degree than the albumin.

Protein adsorption and platelet adhesion on the surface of an oxygenator membrane.

Platelet adhesion on an oxygenator membrane is associated with thrombocytopenia or thrombus formation during extracorporeal circulation. The authors evaluated protein adsorption and platelet adhesion on three oxygenator hollow fiber membranes fabricated with polypropylene, silicone, and double layer polyolefin. Adsorbed proteins were analyzed by bicinchoninic acid protein assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis, and Western blot. Platelet adhesion was assessed with enzyme immunoassays using monoclonal antibodies directed against CD42b and CD61. After 3 hr of incubation at 37 degrees C in whole blood, the amount of adsorbed protein was the least on silicone and increased from silicone < double polyolefin < polypropylene. The adsorbed protein pattern was similar; however, silicone showed less adsorption for all protein bands, and the gamma chain of fibrinogen was not detected. In contrast, double polyolefin showed the highest fibrinogen adsorption. The optical density at a wavelength of 450 nm for CD42b was 1.47 +/- 0.35 in polypropylene, 1.16 +/- 0.38 in silicone, and 1.85 +/- 0.19 in double polyolefin (p < 0.01 vs silicone) and for CD61 0.98 +/- 0.39 in polypropylene, 0.91 +/- 0.22 in silicone, and 1.69 +/- 0.25 in double polyolefin (p < 0.01 vs silicone and polypropylene). These data suggest that silicone is advantageous for long term extracorporeal respiratory support in terms of less platelet adhesion and no plasma leakage through the pores.