Risk of Hemorrhage during Needle-Based Ophthalmic Regional Anesthesia in Patients Taking Antithrombotics: A Systematic Review.

BACKGROUND:Patients undergoing ophthalmic surgery are usually elderly and, due to systemic disease, may be on long-term therapy, such as antithrombotic agents. Rates of hemorrhagic complications associated with invasive procedures may be increased by the use of anticoagulants and antiplatelet agents. OBJECTIVE:To compare the incidence of hemorrhagic complications in patients undergoing needle-based ophthalmic regional anesthesia between patients on antithrombotic therapy and those not on such therapy. METHODS:A systematic review was conducted by two independent reviewers based on searches of Cochrane, LILACS, PubMed, Scopus, Web of Science, and the "gray" literature (Google Scholar). The end search date was May 8, 2015, across all databases. RESULTS:Five studies met the eligibility criteria. In three studies, individual risk of bias was low, and in two of them, moderate. In all studies, no differences regarding mild to moderate incidence of hemorrhagic complications were found between patients using antithrombotics (aspirin, clopidogrel, and warfarin) and those not using them. Rates of severe hemorrhagic complication were very low (0.04%) in both groups, supporting the safety of needle blocks, even in patients using antithrombotics. High heterogeneity across studies prevented meta-analysis. Limitations to these results include low statistical power in three experimental studies and a large 95% confidence interval in the two retrospective cohorts. CONCLUSION:In this review, none of the selected studies showed significant bleeding related to needle-based ophthalmic regional anesthesia in association with the use of aspirin, clopidogrel, or vitamin K inhibitors. Since the available data is not powerful enough to provide a reliable evaluation of the true effect of antithrombotics in this setting, new studies to address these limitations are necessary

Flow diagram of literature search and selection criteria.

<p>Flow diagram of literature search and selection criteria.</p

Precision measurement of the structure of the CMS inner tracking system using nuclear interactions

The structure of the CMS inner tracking system has been studied using nuclear interactions of hadrons striking its material. Data from proton-proton collisions at a center-of-mass energy of 13 TeV recorded in 2015 at the LHC are used to reconstruct millions of secondary vertices from these nuclear interactions. Precise positions of the beam pipe and the inner tracking system elements, such as the pixel detector support tube, and barrel pixel detector inner shield and support rails, are determined using these vertices. These measurements are important for detector simulations, detector upgrades, and to identify any changes in the positions of inactive elements

Description and performance of track and primary-vertex reconstruction with the CMS tracker

A description is provided of the software algorithms developed for the CMS tracker both for reconstructing charged-particle trajectories in proton-proton interactions and for using the resulting tracks to estimate the positions of the LHC luminous region and individual primary-interaction vertices. Despite the very hostile environment at the LHC, the performance obtained with these algorithms is found to be excellent. For tbar t events under typical 2011 pileup conditions, the average track-reconstruction efficiency for promptly-produced charged particles with transverse momenta of p(T) > 0.9GeV is 94% for pseudorapidities of |η| < 0.9 and 85% for 0.9 < |η| < 2.5. The inefficiency is caused mainly by hadrons that undergo nuclear interactions in the tracker material. For isolated muons, the corresponding efficiencies are essentially 100%. For isolated muons of p(T) = 100GeV emitted at |η| < 1.4, the resolutions are approximately 2.8% in p(T), and respectively, 10μm and 30μm in the transverse and longitudinal impact parameters. The position resolution achieved for reconstructed primary vertices that correspond to interesting pp collisions is 10–12μm in each of the three spatial dimensions. The tracking and vertexing software is fast and flexible, and easily adaptable to other functions, such as fast tracking for the trigger, or dedicated tracking for electrons that takes into account bremsstrahlung