25 research outputs found
In Vitro and in Vivo Study of Sustained Nitric Oxide Release Coating Using Diazeniumdiolate-doped Poly(vinyl chloride) Matrix with Poly(lactide-co-glycolide) Additive
Nitric oxide (NO) is an endogenous vasodilator as well as natural inhibitor of platelet adhesion and activation that can be released from a NO donor species, such as diazeniumdiolated dibutylhexanediamine (DBHD/N2O2) within a polymer coating. In this study, various Food and Drug Administration approved poly(lactic-co-glycolic acid) (PLGA) species were evaluated as additives to promote a prolonged NO release from DBHD/N2O2 within a plasticized poly(vinyl chloride) (PVC) matrix. When using an ester-capped PLGA additive with a slow hydrolysis time, the resulting coatings continuously release between 7 and 18 × 10−10 mol cm−2 min−1 NO for 14 days at 37 °C in PBS buffer. The corresponding pH changes within the polymer films were visualized using pH sensitive indicators and are shown to correlate with the extended NO release pattern. The optimal combined diazeniumdiolate/PLGA-doped NO release (NOrel) PVC coating was evaluated in vitro and its effect on the hemodynamics was also studied within a 4 h in vivo extracorporeal circulation (ECC) rabbit model of thrombogenicity. Four out of 7 control circuits clotted within 3 h, whereas all the NOrel coated circuits were patent after 4 h. Platelet counts on the NOrel ECC were preserved (79 ± 11% compared to 54 ± 6% controls). The NOrel coatings showed a significant decrease in the thrombus area as compared to the controls. Results suggest that by using ester-capped PLGAs as additives to a conventional plasticized PVC material containing lipophilic diazeniumdiolates, the NO release can be prolonged for up to 2 weeks by controlling the pH within the organic phase of the coating
Extra-corporeal membrane oxygenation for refractory cardiogenic shock after adult cardiac surgery:a systematic review and meta-analysis
Background - Postcardiotomy cardiogenic shock (PCCS) refractory to inotropic support and intra-aortic balloon pump (IABP) occurs rarely but is almost universally fatal without mechanical circulatory support. In this systematic review and meta-analysis we looked at the evidence behind the use of veno-arterial extra-corporeal membrane oxygenation (VA ECMO) in refractory PCCS from a patient survival rate and determinants of outcome viewpoint.
Methods - A systematic review was performed in January 2017 using PubMed (with no defined time period) using the keywords “postcardiotomy”, “cardiogenic shock”, “extracorporeal membrane oxygenation” and “cardiac surgery”. We excluded papers pertaining to ECMO following paediatric cardiac surgery, medical causes of cardiogenic shock, as well as case reports, review articles, expert opinions, and letters to the editor. Once the studies were collated, a meta-analysis was performed on the proportion of survivors in those papers that met the inclusion criteria. Meta-regression was performed for the most commonly reported adverse prognostic indicators (API).
Results - We identified 24 studies and a cumulative pool of 1926 patients from 1992 to 2016. We tabulated the demographic data, including the strengths and weaknesses for each of the studies, outcomes of VA ECMO for refractory PCCS, complications, and APIs. All the studies were retrospective cohort studies. Meta-analysis of the moderately heterogeneous data (95% CI 0.29 to 0.34, p 70 years, 95% CI −0.057 to 0.001, P = 0.058), and long ECMO support (95% CI −0.068 to 0.166, P = 0.412). Postoperative renal failure, high EuroSCORE (>20%), diabetes mellitus, obesity, rising lactate whilst on ECMO, gastrointestinal complications had also been reported.
Conclusion - Haemodynamic support with VA ECMO provides a survival benefit with reasonable intermediate and long-term outcomes. Many studies had reported advanced age, renal failure and prolonged VA ECMO support as the most likely APIs for VA ECMO in PCCS. EuroSCORE can be utilized to anticipate the need for prophylactic perioperative VA ECMO in the high-risk category. APIs can be used to aid decision-making regarding both the institution and weaning of ECMO for refractory PCCS
Contexte géodynamique et pics métallogéniques au Maroc en liaison avec plutonisme, volcanisme et hydrothermalismes associés
U/Pb ages of magmatism in the Zgounder epithermal Ag-Hg deposit, Sirwa window, Anti-Atlas, Morocco
International audienc