Hemocompatibility of a Miniaturized Extracorporeal Membrane Oxygenation and a Pumpless Interventional Lung Assist in Experimental Lung Injury

Abstract

Extracorporeal membrane oxygenation (ECMO) is used for most severe acute respiratory distress syndrome cases in specialized centers. Hemocompatibility of devices depends on the size and modification of blood contacting surfaces as well as blood flow rates. An interventional lung assist using arteriovenous perfusion of a low-resistance oxygenator without a blood pump (Novalung, Hechingen, Germany) or a miniaturized ECMO with reduced filling volume and a diagonal blood pump (Deltastream, Medos AG, Stolberg, Germany) could optimize hemocompatibility. The aim of the study was to compare hemocompatibility with conventional ECMO. Female pigs were connected to extracorporeal circulation for 24 h after lavage induced lung injury (eight per group). Activation of coagulation and immune system as well as blood cell damage was measured. A P value <0.05 was considered significant. Plasmatic coagulation was slightly activated in all groups demonstrated by increased thrombin-anti-thrombin III-complex. No clinical signs of bleeding or thromboembolism occurred. Thrombelastography revealed decreased clotting capacities after miniaturized ECMO, probably due to significantly reduced platelet count. These resulted in reduced dosage of intravenous heparin. Scanning electron microscopy of oxygenator fibers showed significantly increased binding and shape change of platelets after interventional lung assist. In all groups, hemolysis remained negligible, indicated by low plasma hemoglobin concentration. Interleukin 8 and tumor necrosis factor-alpha concentration as well as leukocyte count remained unchanged. Both devices demonstrated adequate hemocompatibility for safe clinical application, although a missing blood pump did not increase hemocompatibility. Further studies seem necessary to analyze the influence of different blood pumps on platelet drop systematically.

Biocompatibility Assessment of the CentriMag-Novalung Adult ECMO Circuit in a Model of Acute Pulmonary Hypertension

“…Interestingly, the average number of platelets was similar throughout the study in both the groups as seen in Table 1. This is in contrast to previous studies in other oxygenator devices that show a sharp drop in platelet counts following initiation of ECMO 33 .…”

Twelve Hours In Vitro Biocompatibility Testing of Membrane Oxygenators

“…Furthermore, the results concerning the coagulation system and PLT counts, as well as pCO 2 and pH values, were comparable with in vivo settings after 12 hr. 19,20 These findings show that conditions comparable with in vivo settings could be achieved in vitro. Nonetheless, further investigations on the influence of the nutrient solution on the rheological properties of the blood (e.g., the dynamic viscosity) and also on the pH values are necessary.…”

Standardized methods to quantify thrombogenicity of blood‐contacting materials via thromboelastography

“…One of the major reasons for doing this is because the TEG analyzer has been widely used in studying the abnormality of blood in the clinical setting such as during cardio-pulmonary bypass surgery, vascular stent placement, and graft implantation as well as during the resuscitation using ECMO. 42,43 We propose that TEG be used as a standard in vitro assay for thrombogenicity as it holds promise to provide an in vitro assay that can be predictive of in vivo biocompatibility.…”