Blood management in fast-track orthopedic surgery: An evidence-based narrative review

Background and purpose: Innovations able to maintain patient safety while reducing the amount of transfusion add value to orthopedic procedures. Opportunities for improvement arise especially in elective procedures, as long as room for planning is available. Although many strategies have been proposed, there is no consensus about the most successful combination. The purpose of this investigation is to identify information to support blood management strategies in fast-track total joint arthroplasty (TJA) pathway, to (i) support clinical decision making according to current evidence and best practices, and (ii) identify critical issues which need further research. Methods and materials: We identified conventional blood management strategies in elective orthopedic procedures. We performed an electronic search about blood management strategies in fast-track TJA. We designed tables to match every step of the former with the latter. We submitted the findings to clinicians who operate using fast-track surgery protocols in TJA at our research hospital. Results: Preoperative anemia detection and treatment, blood anticoagulants/aggregants consumption, transfusion trigger, anesthetic technique, local infiltration analgesia, drainage clamping and removals, and postoperative multimodal thromboprophylaxis are the factors which can add best value to a fast-track pathway, since they provide significant room for planning and prediction. Conclusion: The difference between conventional and fast-track pathways does not lie in the contents of blood management, which are related to surgeons/surgeries, materials used and patients, but in the way these contents are integrated into each other, since elective orthopedic procedures offer significant room for planning. Further studies are needed to identify optimal regimens

Normal endothelial function in carriers of the apolipoprotein A-IMilano mutant despite low HDL-cholesterol levels

Carriers of the apolipoprotein A-IMilano (apoA-IM) mutant show severe reductions in the plasma concentration of antiatherogenic HDL but do not present with preclinical atherosclerosis and premature CHD. Aim of the present study was to investigate endothelial function in A-IM carriers, since low HDL-C levels have been associated with features of endothelial dysfunction. Plasma concentrations of soluble cell adhesion molecules (sCAMs) and forearm arterial compliance (FAC) during reactive hyperemia were evaluated in 21 A-IM carriers, 21 healthy subjects with low HDL-C, and 42 controls. Low HDL-C subjects had significantly higher plasma sCAM levels than controls (sVCAM-1: 656.3\ub149.3 vs 502.6\ub125.5 ng/ml; sICAM-1: 335.6\ub121.5 vs 267.0\ub18.9 ng/ml; sE-selectin: 62.9\ub14.1 vs 47.9\ub13.0 ng/ml); on the contrary, no differences were detected between A-IM carriers (sVCAM-1: 550.6\ub132.1 ng/ml; sICAM-1: 309.8\ub126.9 ng/ml; sE-selectin: 52.3\ub14.3 ng/ml) and controls. Low HDL-C subjects had lower FAC than controls, while no differences were detected between A-IM carriers and controls. These results suggest that HDL from A-IM carriers may be more efficient than control HDL in modulating endothelial function. To test this hypothesis, plasma HDL were isolated from 6 A-IM carriers and 6 controls, and their ability to inhibit VCAM-1 expression and to induce eNOS was tested in cultured endothelial cells. A-IM HDL were two times more effective than control HDL in reducing TNFalpha-induced VCAM-1 expression; the inhibition occurred at a transcriptional level, as demonstrated by RT-PCR. In addition, cells exposed to A-IM HDL showed higher expression of eNOS than cells treated with control HDL. In conclusion, despite the very low HDL-C levels, A-IM carriers do not display features of endothelial dysfunction, such as the increase of circulating sCAM levels and the impairment of arterial compliance, probably because of a superior ability of A-IM HDL to protect the endothelium

Electrically Switchable Photonic Molecule Laser

We have studied the coherent intercavity coupling of the evanescent fields of the whispering gallery modes of two terahertz quantum-cascade lasers implemented as microdisk cavities. The electrically pumped single-mode operating microcavities allow to electrically control the coherent mode coupling for proximity distances of the cavities up to 30-40 \mu\m. The optical emission of the strongest coupled photonic molecule can be perfectly switched by the electrical modulation of only one of the coupled microdisks. The threshold characteristics of the strongest coupled photonic molecule demonstrates the linear dependence of the gain of a quantum-cascade laser on the applied electric field.Comment: 4 pages, 4 figure

Nonequilibrium Green's function theory for transport and gain properties of quantum cascade structures

The transport and gain properties of quantum cascade (QC) structures are investigated using a nonequilibrium Green's function (NGF) theory which includes quantum effects beyond a Boltzmann transport description. In the NGF theory, we include interface roughness, impurity, and electron-phonon scattering processes within a self-consistent Born approximation, and electron-electron scattering in a mean-field approximation. With this theory we obtain a description of the nonequilibrium stationary state of QC structures under an applied bias, and hence we determine transport properties, such as the current-voltage characteristic of these structures. We define two contributions to the current, one contribution driven by the scattering-free part of the Hamiltonian, and the other driven by the scattering Hamiltonian. We find that the dominant part of the current in these structures, in contrast to simple superlattice structures, is governed mainly by the scattering Hamiltonian. In addition, by considering the linear response of the stationary state of the structure to an applied optical field, we determine the linear susceptibility, and hence the gain or absorption spectra of the structure. A comparison of the spectra obtained from the more rigorous NGF theory with simpler models shows that the spectra tend to be offset to higher values in the simpler theories.Comment: 44 pages, 16 figures, appearing in Physical Review B Dec 200

Osteocalcin as a potential risk biomarker for cardiovascular and metabolic diseases

Clear evidence supports a role for circulating and locally-produced osteocalcin (OC) in the pathophysiology of cardiovascular (CV) lesions and CV risk, also in combination with metabolic changes, including type 2 diabetes mellitus (T2DM). Reduced plasma OC levels are associated with greater incidence of pathological CV changes, like arterial and valvular calcification, coronary and carotid atherosclerosis and increased carotid intima-media thickness. The actual relationship between OC levels and incidence of major CV events is, however, still unclear. Moreover, reduced circulating OC levels have been mostly associated with insulin resistance, metabolic syndrome or T2DM, indicating relevant OC actions on pancreatic \u3b2-cells and insulin secretion and activity. Based on these observations, this review article will attempt to summarize the current evidence on the potential usefulness of circulating OC as a biomarker for CV and metabolic risk, also evaluating the currently open issues in this area of research