Literature-based considerations regarding organizing and performing cardiac surgery against the backdrop of the coronavirus pandemic

Background: The ongoing coronavirus disease 2019 (Covid-19) pandemic presents challenges for surgeons of all disciplines, including cardiologists. The volume of cardiac surgery cases has to comply with the mandatory constraints of healthcare capacities. The treatment of Covid-19-positive patients must also be considered. Unfortunately, no scientific evidence is available on this issue. Therefore, this study aimed to offer some consensus-based considerations, derived from available scientific papers, regarding the organization and performance of cardiac surgery against the backdrop of the Covid-19 pandemic. Methods Key recommendations were extracted from recent literature concerning cardiac surgery. RESULTS: Reducing elective cardiac procedures should be based on frequent clinical assessment of patients on the waiting list (every one or two weeks) and the current local status of the Covid-19 pandemic. Screening tests at admission for every patient are broadly recommended. Where appropriate, alternative treatment methods can be considered, including percutaneous techniques and minimally invasive surgery, if performed by experienced cardiac surgery teams. Conclusions There is little evidence on the strategies to organize cardiac surgery in the Covid-19 pandemic. Most authors agree on reducing elective operations based on patients' clinical condition and the status of the Covid-19 pandemic. Admission screenings and the use of percutaneous or minimally invasive approaches should be preferred to reduce in-hospital stays

Prevalence and management of driveline infections in mechanical circulatory support - a single center analysis

Background: Driveline infections in continuous-flow left ventricular assist devices (cf-LVAD) remain the most common adverse event. This single-center retrospective study investigated the risk factors, prevalence and management of driveline infections. :Methods Patients treated after cf-LVAD implantation from December 2014 to January 2020 were enrolled. Baseline data were collected and potential risk factors were elaborated. The multi-modal treatment was based on antibiotic therapy, daily wound care, surgical driveline reposition, and heart transplantation. Time of infection development, freedom of reinfection, freedom of heart transplantation, and death in the follow-up time were investigated. Results: Of 75 observed patients, 26 (34.7%) developed a driveline infection. The mean time from implantation to infection diagnosis was 463 (+/- 399; range, 35-1400) days. The most common pathogen was Staphylococcus aureus (n = 15, 60%). First-line therapy was based on antibiotics, with a primary success rate of 27%. The majority of patients (n = 19; 73.1%) were treated with surgical reposition after initial antibiotic therapy. During the follow-up time of 569 (+/- 506; range 32-2093) days, the reinfection freedom after surgical transposition was 57.9%. Heart transplantation was performed in eight patients due to resistant infection. The overall mortality for driveline infection was 11.5%. Conclusions: Driveline infections are frequent in patients with implanted cf-LVAD, and treatment does not efficiently avoid reinfection, leading to moderate mortality rates. Only about a quarter of the infected patients were cured with antibiotics alone. Surgical driveline reposition is a reasonable treatment option and does not preclude subsequent heart transplantation due to limited reinfection freedom

Hysteresis and synchronization in a two-level system driven by external noise

The paper discusses a combined effect of periodic and random perturbations on the onset of hysteresis in a generic two-state system. The interplay of both noises is investigated pointing out variations in signal tuning to the external driving force and their influence on the area and shape of the hysteresis. As an extension to former studies relating dynamic hysteresis to stochastic resonance and synchronization of passages in a double well system, in the present work the effect of the field asymmetry on the response of the system is analyzed

Temperature Dependence of the Lower Critical Field of the Noncentrosymmetric Superconductor <i>α</i> ‐BiPd

International audienceTemperature variation of the lower critical H c1 field in the noncentrosymmetric superconductor α-BiPd is probed by local magnetization measurements using Hall micromagnetometry, performed down to 0.3 K in a magnetic field applied along the crystallographic b axis. Below a critical temperature T c ≃ 3.8 K, a conventional H c1 ðTÞ dependence is found, typical for a single-band s-wave superconductor. The obtained data imply an absence of spin-triplet component in the superconducting wavefunction and marginal multiband effects in this material, which contradicts some literature reports

Wheat Straw Biochar and NPK Fertilization Efficiency in Sandy Soil Reclamation

Intensive land use including cultivation may result in soil degradation. Restoring natural conditions or utility values called reclamation usually requires prior improvement of soil properties by using fertilizers or soil amendments. Special attention is paid to biochar, as it can improve soil physical and chemical properties. Therefore, amendment is potentially useful for preparation of degraded soil for future vegetation. In pot experiments, we studied the effect of wheat straw biochar (5% v/w) (soil with biochar (S + BC)), two rates of mineral fertilizer (no fertilizer as a control set (SC) and single initial dose of fertilizer (S + NPK)), and combination of biochar and fertilizer (S + B C + NPK) on sandy soil properties and grass growth. Biochar significantly increased soil pH, total organic carbon content (TOC), and volumetric water content (VWC, +24% after one week of measurements). However, dry mass of grass shoots was lower in S + BC than in SC (&minus;38%). It was also observed that, in fertilizer, applied sets high concentrations of salts caused crust formation, surface cracking, and overdrying. Considering the results, biochar may be useful for increasing sandy substrate fertility, providing proper conditions for revegetation during reclamation