First experience with the new extracorporeal membrane oxygenation system Colibrì.

INTRODUCTION: Extracorporeal membrane oxygenation (ECMO) is increasingly used for circulatory or pulmonary support not only in-hospital but also out-of-hospital. Small dimensions and a lightweight design are important, especially for out-of-hospital use but also for intra-hospital transportation of patients who require ECMO support. We share our first experience with the new Colibrì ECMO system. PATIENTS AND METHODS: From December 2022 to January 2023, we used the new Colibrì extracorporeal circulation (ECC) system in six patients with cardiac or pulmonary failure. RESULTS: The Colibrì system was used in-hospital in six patients with post-cardiac surgery low output syndrome, respiratory failure due to influenza or acute respiratory distress syndrome, cardiogenic shock, pulmonary embolism, and failed weaning from cardiopulmonary bypass. The system was implanted in venovenous (VV) and venoarterial (VA) fashion in 3 patients, respectively. In one patient, the configuration was switched from VA to VV after cardiac recovery. One patient received left-ventricular unloading using the IMPELLA®5.5. ECMO run time was 1 to 13 days. We did not notice any ECC system-associated complications. No ECMO system changes were required. CONCLUSION: Our case series concludes that the new Colibrì system is safe and effective for in-hospital ECMO indications. The small dimensions and lightweight design are very beneficial for the transportation of patients. It might be especially helpful for out-of-hospital situations.

Impact of Age on Endothelial Function of Saphenous Vein Grafts in Coronary Artery Bypass Grafting.

BACKGROUND: An intact and functionally preserved endothelial layer in the graft is crucial for myocardial perfusion and graft patency after coronary artery bypass grafting (CABG). We hypothesized that old age is a risk factor for decreased endothelial function of bypass grafts. Thus, we investigated the impact of age in patients treated with CABG on endothelial function in saphenous vein grafts. METHODS: We mounted the saphenous vein graft segments of CABG patients < 70 (n = 33) and ≥70 (n = 40) years of age in organ bath chambers and exposed them to potassium chloride (KCl) and phenylephrine (PE) to test the receptor-independent and -dependent contractility, followed by exposure to acetylcholine (ACh) and sodium nitroprusside (SNP) to test the endothelial-dependent and -independent relaxation. RESULTS: The maximal contraction induced by KCl (2.3 ± 1.8 vs. 1.8 ± 2 g) was stronger in patients ≥ 70 years of age. The relative contraction induced by PE in % of KCl (167 ± 64 vs. 163 ± 59%) was similar between groups. Patients aged < 70 years showed a higher endothelial-dependent relaxation induced by acetylcholine than patients ≥ 70 years (51 ± 27 vs. 42 ± 18%). The relaxation induced by SNP was similar between both groups. CONCLUSIONS: The endothelial function of saphenous vein bypass grafts decreases during aging. Thus, age should be considered when improving graft maintenance.

Proteins Adsorbed during Intraoperative Hemoadsorption and Their In Vitro Effects on Endothelium.

(1) Background: Hemoadsorption is a method of blood purification with a wide spectrum of indications. Pre-emptive use of hemoadsorption in patients undergoing heart surgery with cardiopulmonary bypass is considered to reduce the risk of postoperative systemic inflammatory response syndrome. The current study aimed to identify the spectrum of blood proteins adsorbed on the polymer matrix of the CytoSorb hemoadsorption system and to investigate their influence on cultured endothelial cells in vitro. (2) Methods: Adsorbers used for intraoperative hemoadsorption were obtained from patients undergoing on-pump valve surgery in acute endocarditis. Proteins were extracted from the adsorbers, purified, identified with mass-spectrometry and applied to cultured human aortic endothelial cells. (3) Results: A broad range of blood proteins were identified in the material eluted from the CytoSorb adsorber. When added to cultured ECs, these protein extracts caused severe reduction in cell viability and migration. After 24 h exposure, transcriptional changes with up-regulation of multiple metabolic regulators were observed and verified on the protein level. Genes responsible for control of mitosis were significantly down-regulated. (4) Conclusions: In summary, our data reveal that intraoperative hemoadsorption allows broad spectrum removal of a wide range of molecules eliciting endothelial damage.

On the Localization of Persistent Currents Due to Trapped Magnetic Flux at the Stacking Faults of Graphite at Room Temperature.

Granular superconductivity at high temperatures in graphite can emerge at certain two-dimensional (2D) stacking faults (SFs) between regions with twisted (around the c-axis) or untwisted crystalline regions with Bernal (ABA…) and/or rhombohedral (ABCABCA…) stacking order. One way to observe experimentally such 2D superconductivity is to measure the frozen magnetic flux produced by a permanent current loop that remains after removing an external magnetic field applied normal to the SFs. Magnetic force microscopy was used to localize and characterize such a permanent current path found in one natural graphite sample out of ∼50 measured graphite samples of different origins. The position of the current path drifts with time and roughly follows a logarithmic time dependence similar to the one for flux creep in type II superconductors. We demonstrate that a ≃10 nm deep scratch on the sample surface at the position of the current path causes a change in its location. A further scratch was enough to irreversibly destroy the remanent state of the sample at room temperature. Our studies clarify some of the reasons for the difficulties of finding a trapped flux in a remanent state at room temperature in graphite samples with SFs.

Cardiogenic shock with highly complicated course after influenza A virus infection treated with vva-ECMO and Impella CP (ECMELLA): a case report.

BACKGROUND: The value of mechanical circulatory support (MCS) in cardiogenic shock, especially the combination of the ECMELLA approach (Impella combined with ECMO), remains controversial. CASE PRESENTATION: A previously healthy 33-year-old female patient was submitted to a local emergency department with a flu-like infection and febrile temperatures up to 39 °C. The patient was tested positive for type-A influenza, however negative for SARS-CoV-2. Despite escalated invasive ventilation, refractory hypercapnia (paCO2: 22 kPa) with severe respiratory acidosis (pH: 6.9) and a rising norepinephrine rate occurred within a few hours. Due to a Horovitz-Index < 100, out-of-centre veno-venous extracorporeal membrane oxygenation (vv-ECMO)-implantation was performed. A CT-scan done because of anisocoria revealed an extended dissection of the right vertebral artery. While the initial left ventricular function was normal, echocardiography revealed severe global hypokinesia. After angiographic exclusion of coronary artery stenoses, we geared up LV unloading by additional implantation of an Impella CP and expanded the vv-ECMO to a veno-venous-arterial ECMO (vva-ECMO). Clinically relevant bleeding from the punctured femoral arteries resulted in massive transfusion and was treated by vascular surgery later on. Under continued MCS, LVEF increased to approximately 40% 2 days after the initiation of ECMELLA. After weaning, the Impella CP was explanted at day 5 and the vva-ECMO was removed on day 9, respectively. The patient was discharged in an unaffected neurological condition to rehabilitation 25 days after the initial admission. CONCLUSIONS: This exceptional case exemplifies the importance of aggressive MCS in severe cardiogenic shock, which may be especially promising in younger patients with non-ischaemic cardiomyopathy and potentially reversible causes of cardiogenic shock. This case impressively demonstrates that especially young patients may achieve complete neurological restoration, even though the initial prognosis may appear unfavourable.

Positive impact of retrograde autologous priming in adult patients undergoing cardiac surgery: a randomized clinical trial.

BACKGROUND: Adult cardiac surgery with extracorporeal circulation is known to be associated with increased risk of blood transfusion leading to adverse outcomes. Procedures like retrograde autologous priming (RAP) may reduce these negative side effects. This randomized prospective study was initiated to assess whether RAP using specifically designed RAP bag (Terumo) has immediate effects on patient outcome. METHODS: One hundred eighteen adults undergoing elective CABG or elective aortic valve replacement were randomly assigned by a computer program into two groups: the RAP group (n = 54) in which the retrograde autologous priming was applied and the non-RAP (n = 64) group in which the same setting was used without the possibility to save priming volume. Patient demographics, preoperative characteristics and postoperative outcomes were analyzed for both groups. RESULTS: The primary endpoint defined as rate of intraoperative blood transfusion was significantly reduced in the RAP-group (p = 0.04). The absolute risk reduction for RAP managed patients was 13.5 percent points. There were no significant differences in operation time and blood loss. No deaths and no myocardial infarctions were observed. The number of patients needed to treat to prevent at least one red blood cell transfusion was around 8 (NNT = 7.42). CONCLUSIONS: Retrograde autologous priming is a safe and less invasive procedure which achieves clear benefits for adult cardiac surgery patients. In the light of increasing red blood cell transfusion risks and costs and the wish of patients to avoid a transfusion implementation of retrograde autologous priming is an interesting option. TRIAL REGISTRATION: German Clinical Trials Register ID: DRKS00013512 , registered 04 December 2017.

Electrical properties of ZnO single nanowires.

We have investigated the electrical resistance R(T) of ZnO nanowires of ≈ 400 nm diameter as a function of temperature, between 30 K and 300 K, and frequency in the range 40 Hz to 30 MHz. The measurements were done on the as-prepared and after low-energy proton implantation at room temperature. The temperature dependence of the resistance of the wire, before proton implantation, can be well described by two processes in parallel. One process is the fluctuation induced tunneling conductance (FITC) and the other the usual thermally activated process. The existence of a tunneling conductance was also observed in the current-voltage ([Formula: see text]) results, and can be well described by the FITC model. Impedance spectroscopy measurements in the as-prepared state and at room temperature, indicate and support the idea of two contributions of these two transport processes in the nanowires. Electron backscatter diffraction confirms the existence of different crystalline regions. After the implantation of H(+) a third thermally activated process is found that can be explained by taking into account the impurity band splitting due to proton implantation.

EuroSCORE directed intraaortic balloon pump placement in high-risk patients undergoing cardiac surgery--retrospective analysis of 267 patients.

OBJECTIVES: Intraaortic balloon pump replacement (IABP) is the most widely used circulatory assist device today and is utilized in a wide range of serious cardiovascular conditions. We examined the effects on mortality of pre-, intra-, or postoperative IABP support in patients undergoing cardiac surgery compared to high-risk patients without IABP support. METHODS: Between June 2001 and April 2004, 267 patients either received preoperative IABP support (n=62), an intra- or postoperative IABP (n=113) or had no IABP (n=92). Perioperative mortality was calculated with the EuroSCORE. RESULTS: Patients with preoperative IABP and without IABP support had a lower ejection fraction [37 (29; 50) % and (39 (30; 53)) % vs. (50 (39; 65)) %, P = 0.0001], more frequent unstable angina (38/62 and 53/92 vs. 37/113, P = 0.0004) and recent myocardial infarctions (33/62 and 51/92 vs. 26/113, P = 0.0001). The number of emergency procedures was also significantly higher (36/62 and 65/92 vs. 27/113, P < or = 0.01). Patients with intra-, or postoperative IABP support and patients without IABP support had a longer ICU-stay [7.5 (5; 17.75)) and (7 (5; 15.5)) days vs. (6 (3; 10) days, P = 0.023, P = 0.015]. The overall hospital stay of patients without IABP [18.5 (14; 29) days] and intra-/postoperative IABP support [19, (14; 28) days] were significantly longer (P = 0.007) compared to patients with preoperative support [14 (11.5; 20.5) days]. Whereas we found a trend towards reduced mortality in high-risk non-emergency patients with preoperative support, emergency patients and patients receiving intra- and postoperative support had significantly higher mortality rates than predicted by the EuroSCORE. Both emergency and non-emergency patients without IABP insertion had a significantly higher actual mortality than predicted (29.5% vs. 13.7%, P = 0.03 and 38.1% vs. 26.3%, P < 0.0001). The overall actual mortality between patients with preoperative IABP insertion and patients without preoperative IABP did not significantly differ (14/62 vs. 29/92, P = 0.27). The EuroSCORE proved to be a valid predictor for perioperative mortality among high-risk non-emergency and emergency patients with preoperative IABP support at lower score sums, but failed at higher score sums (>8) and among patients with intra- and postoperative IABP insertion. CONCLUSION: Preoperative IABP support is indicated in high-risk non-emergency patients. The benefit of preoperative IABP insertion in emergency patients and intra- and postoperative IABP support still remains controversial and needs to be elucidated in further prospective, randomized studies.