Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2

The KWS-2 SANS diffractometer is dedicated to the investigation of soft matter and biophysical systems covering a wide length scale, from nm to &#181;m. ...

Forschungszentrum Jülich GmbH

Several techniques have been discussed as alternatives to the intermittent bolus thermodilution cardiac output (COPAC) measurement by the pulmonary artery catheter (PAC). However, these techniques usually require a central venous line, an additional catheter, or a special calibration procedure. A new arterial pressure-based cardiac output (COAP) device (FloTractrade mark, Vigileotrade mark; Edwards Lifesciences, Irvine, CA, USA) only requires access to the radial or femoral artery using a standard arterial catheter and does not need an external calibration. We validated this technique in critically ill patients in the intensive care unit (ICU) using COPAC as the method of reference.

Evaluation of a new arterial pressure-based cardiac output device requiring no external calibration.

Severe pulmonary and cardiopulmonary failure resistant to critical care treatment leads to hypoxemia and hypoxia-dependent organ failure. New treatment options for cardiopulmonary failure are necessary even for patients in outlying medical facilities. If these patients are in need of specialized center treatment, additional emergency medical service has to be carried out quick and safely. We describe our experiences with a pumpless extracorporeal lung assist (PECLA/iLA) for out-of-center emergency treatment of hypercapnic respiratory failure and the use of a newly developed hand-held extracorporeal membrane oxygenation (ECMO) system in cardiac, pulmonary, and cardiopulmonary failure (EMERGENCY-LIFE Support System, ELS System, MAQUET Cardiopulmonary AG, Hechingen, Germany). Between March 2000 and April 2009, we used the PECLA System (n = 20) and the ELS System (n = 33) in adult patients. Cannulation was employed using percutaneous vessel access. The new hand-held ELS System consists of a centrifugal pump and a membrane oxygenator, both mounted on a special holder system for storing on a standard patient gurney for air or ground ambulance transfer. Bedside cannulation processes were uneventful. The PECLA System resulted in sufficient CO(2) removal. In all ECMO patients, oxygen delivery and systemic blood flow could be restored and vasopressor support was markedly down. Hospital survival rate in the PECLA group was 50%, and 61% in the ECMO group. Out-of-center emergency treatment of hypercapnic pulmonary failure with pumpless extracorporeal gas exchange and treatment of cardiac, pulmonary, and cardiopulmonary failure with this new hand-held ECMO device is safe and highlyeffective. Patient outcome in cardiopulmonary organ failure could be improved.

Emergency use of extracorporeal membrane oxygenation in cardiopulmonary failure.

In patients with severe cardiopulmonary failure extracorporeal assist devices are to support patients during resuscitation, for transportation, until organ recovery, and as bridge to further therapeutic modalities. We report on our first experience with the new Cardiohelp system for interhospital transfer of cardiopulmonarily compromised patients. The Cardiohelp system was used for transportation and in-house treatment in six male patients with a mean age of 41±17 years. Five patients suffered respiratory failure; one patient with acute myocardial infarction was in profound cardiogenic shock. Accordingly, the Cardiohelp system was implanted as a venovenous extracorporeal membrane oxygenation (ECMO) in five patients and as a venoarterial system in one patient. The preECMO ventilation time was 0.5-4 days. The patients were transported to our institution by car (n=1) or helicopter (n=5) over a distance of 80-5850 km. The subsequent in-house ECMO support was continued with the Cardiohelp and lasted for 5-13 days. PostECMO ventilation was one to 25 days. A 100% survival was achieved. The portable Cardiohelp system allows location-independent stabilization of cardiopulmonary compromised patients with consecutive interhospital transfer and in-house treatment. The integrated sensors, which register arterial and venous line pressure, blood temperature, hemoglobin as well as SvO(2), greatly alleviate its management and considerably increase safety.

First experience with the ultra compact mobile extracorporeal membrane oxygenation system Cardiohelp in interhospital transport.

Surgery of the ascending aorta and aortic arch has been challenging since its inception as neurological complications may occur significantly affecting the quality of life (QOL).

Quality of life following surgery of ascending aorta and aortic arch with selective antegrade cerebral perfusion.

The ECMOnet score: a useful tool not to be taken absolutely.

Extracorporeal membrane oxygenation (ECMO) is a very effective bridging therapy in patients with cardiogenic shock. To perform coronary angiography in these patients our group developed an unique system to get urgent vascular access with minimal additional vascular complication risk. The 6 Fr coronary catheters are introduced through a standard Y-connector, which is inserted into the arterial cannula of the ECMO-line close to the patient, the blind end of which is then equipped with a haemostatic valve (Check-Flo Performer accessory adapter, Cook Medical, USA). To the best of our knowledge, we here present the first patient, in whom this system had been used to insert an 8 Fr radiofrequency ablation catheter to treat incessant ventricular fibrillation.

A unique access for the ablation catheter to treat electrical storm in a patient with extracorporeal life support.

Based on continuous technical innovations and recent research, extracorporeal membrane oxygenation (ECMO) has become a promising tool in the treatment of patients with acute (cardio)pulmonary failure. Nevertheless, any extracorporeal technique requires a high degree of experience and knowledge, so that a restriction to specialized centres seems to be reasonable. As a consequence of this demand, the need for inter-hospital transfer of patients with severely impaired (cardio)pulmonary function is rising. Unfortunately, most of the ECMO devices used in the clinical setting are not suitable for inter-hospital transport because of their size, weight or complexity. In this article, we describe our first experiences with the airborne transport of 6 patients on a new portable, miniaturized and lightweight extracorporeal circulation system, the Medos deltastream® DP3.

First experience with the deltastream(R) DP3 in venovenous extracorporeal membrane oxygenation and air-supported inter-hospital transport.

We present a small-angle neutron scattering (SANS) structural characterization of n-alkyl-PEO polymer micelles in aqueous solution with special focus on the dependence of the micellar aggregation number on increasing concentration. The single micellar properties in the dilute region up to the overlap concentration ϕ* are determined by exploiting the well characterized unimer exchange kinetics of the model system in a freezing and diluting experiment. The micellar solutions are brought to thermodynamic equilibrium at high temperatures, where unimer exchange is fast, and are then cooled to low temperatures and diluted to concentrations in the limit of infinite dilution. At low temperatures the kinetics, and therefore the key mechanism for micellar rearrangement, is frozen on the experimental time scale, thus preserving the micellar structure in the dilution process. Information about the single micellar structure in the semidilute and concentrated region are extracted from structure factor analysis at high concentrations where the micelles order into fcc and bcc close packed lattices and the aggregation number can be calculated by geometrical arguments. This approach enables us to investigate the aggregation behavior in a wide concentration regime from dilute to 6·ϕ*, showing a constant aggregation number with concentration over a large concentration regime up to a critical concentration about three times ϕ*. When exceeding this critical concentration, the aggregation number was found to increase with increasing concentration. This behavior is compared to scaling theories for star-like polymer micelles.

Studying the concentration dependence of the aggregation number of a micellar model system by SANS.

Following demand from the user community regarding the possibility of improving the experimental resolution, the dedicated high-intensity/extended Q-range SANS diffractometer KWS-2 of the Jülich Centre for Neutron Science at the Heinz Maier-Leibnitz Center in Garching was equipped with a double-disc chopper with a variable opening slit window and time-of-flight (TOF) data acquisition option. The chopper used in concert with a dedicated high-intensity velocity selector enables the tuning at will of the wavelength resolution Δλ/λ within a broad range, from 20% (standard) down to 2%, in a convenient and safe manner following pre-planned or spontaneous decisions during the experiment. The new working mode is described in detail, and its efficiency is demonstrated on several standard samples with known properties and on a completely new crystallizable copolymer system, which were investigated using both the conventional (static) and TOF modes.

Matthias Amann

Jülich Centre for Neutron Science JCNS-1 & Institute of Complex Systems ICS-1

Forschungszentrum Jülich GmbH

Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2

Matthias Amann

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Jülich Centre for Neutron Science JCNS-1 & Institute of Complex Systems ICS-1

Forschungszentrum Jülich GmbH

Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2

Jülich Centre for Neutron Science JCNS-1 & Institute of Complex Systems ICS-1