Does the continuation of low-dose acetylsalicylic acid during the perioperative period of thyroidectomy increase the risk of cervical haematoma? A 1-year experience of two Italian centers

Background: A growing number of patients taking antiplatelet drugs, mainly low-dose acetylsalicylic acid (ASA) (75–150 mg/day), for primary or secondary prevention of thrombotic events, are encountered in every field of surgery. While the bleeding risk due to the continuation of these medications during the perioperative period has been adequately investigated in several surgical specialties, in thyroid surgery it still needs to be clarified. The main aim of this study was to assess the occurrence of cervical haematoma in patients receiving low-dose acetylsalicylic acid, specifically ASA 100 mg/day, during the perioperative period of thyroidectomy. Methods: Patients undergoing thyroidectomy in two high-volume thyroid surgery centers in Italy, between January 2021 and December 2021, were retrospectively analysed. Enrolled patients were divided into two groups: those not taking ASA were included in Group A, while those receiving this drug in Group B. Univariate analysis was performed to compare these two groups. Moreover, multivariate analysis was employed to evaluate the use of low-dose ASA as independent risk factor for cervical haematoma. Results: A total of 412 patients underwent thyroidectomy during the study period. Among them, 29 (7.04%) were taking ASA. Based on the inclusion criteria, 351 patients were enrolled: 322 were included in Group A and 29 in Group B. In Group A, there were 4 (1.24%) cervical haematomas not requiring surgical revision of haemostasis and 4 (1.24%) cervical haematomas requiring surgical revision of haemostasis. In Group B, there was 1 (3.45%) cervical haematoma requiring surgical revision of haemostasis. At univariate analysis, no statistically significant difference was found between the two groups in terms of occurrence of cervical haematoma, nor of the other early complications of thyroidectomy. At multivariate analysis, the use of low-dose ASA did not prove to be an independent risk factor for cervical haematoma. Conclusions: Based on our findings, we believe that in patients receiving this drug, either for primary or secondary prevention of thrombotic events, its discontinuation during the perioperative period of thyroidectomy is not necessary

An X-ray polarimeter for hard X-ray optics

Development of multi-layer optics makes feasible the use of X-ray telescope at energy up to 60-80 keV: in this paper we discuss the extension of photoelectric polarimeter based on Micro Pattern Gas Chamber to high energy X-rays. We calculated the sensitivity with Neon and Argon based mixtures at high pressure with thick absorption gap: placing the MPGC at focus of a next generation multi-layer optics, galatic and extragalactic X-ray polarimetry can be done up till 30 keV.Comment: 12 pages, 7 figure

Characterization of the NNVT capillary plate collimators

In this paper, we report the results of the characterization campaign of two prototypes of Micro-Channel Plates (MCPs), designed as the X-ray collimators for the Large Area Detector on board the eXTP mission. The devices were developed ad-hoc by North Night Vision Technology Co., Ltd. (Nanjing, China). Measurements involved the study of the angular response (rocking curve) of each device to X-rays of different energies. The study evidenced how the angular response of a collimator changes with the energy of the incoming photons, with the onset of side lobes at high energy, which enlarge the effective field of view of the device, causing a potential contamination of the on-axis signal. Nevertheless, the magnitude of this effect is proven to be acceptable in most situations of astrophysical interest. On the lower hand of the energy spectrum, photons may also modify the angular response due to grazing reflection on the inner walls of the collimator, a phenomenon strongly dependent on the degree of roughness of the surfaces involved. The whole campaign took place at the INAF/IAPS laboratories in Rome

POLARIX: a pathfinder mission of X-ray polarimetry

Since the birth of X-ray astronomy, spectral, spatial and timing observation improved dramatically, procuring a wealth of information on the majority of the classes of the celestial sources. Polarimetry, instead, remained basically unprobed. X-ray polarimetry promises to provide additional information procuring two new observable quantities, the degree and the angle of polarization. POLARIX is a mission dedicated to X-ray polarimetry. It exploits the polarimetric response of a Gas Pixel Detector, combined with position sensitivity, that, at the focus of a telescope, results in a huge increase of sensitivity. Three Gas Pixel Detectors are coupled with three X-ray optics which are the heritage of JET-X mission. POLARIX will measure time resolved X-ray polarization with an angular resolution of about 20 arcsec in a field of view of 15 arcmin $\times$ 15 arcmin and with an energy resolution of 20 % at 6 keV. The Minimum Detectable Polarization is 12 % for a source having a flux of 1 mCrab and 10^5 s of observing time. The satellite will be placed in an equatorial orbit of 505 km of altitude by a Vega launcher.The telemetry down-link station will be Malindi. The pointing of POLARIX satellite will be gyroless and it will perform a double pointing during the earth occultation of one source, so maximizing the scientific return. POLARIX data are for 75 % open to the community while 25 % + SVP (Science Verification Phase, 1 month of operation) is dedicated to a core program activity open to the contribution of associated scientists. The planned duration of the mission is one year plus three months of commissioning and SVP, suitable to perform most of the basic science within the reach of this instrument.Comment: 42 pages, 28 figure

Risk factors for postoperative cervical haematoma in patients undergoing thyroidectomy: a retrospective, multicenter, international analysis (REDHOT study)

Background Postoperative cervical haematoma represents an infrequent but potentially life-threatening complication of thyroidectomy. Since this complication is uncommon, the assessment of risk factors associated with its development is challenging. The main aim of this study was to identify the risk factors for its occurrence.Methods Patients undergoing thyroidectomy in seven high-volume thyroid surgery centers in Europe, between January 2020 and December 2022, were retrospectively analysed. Based on the onset of cervical haematoma, two groups were identified: Cervical Haematoma (CH) Group and No Cervical Haematoma (NoCH) Group. Univariate analysis was performed to compare these two groups. Moreover, employing multivariate analysis, all potential independent risk factors for the development of this complication were assessed.Results Eight thousand eight hundred and thirty-nine patients were enrolled: 8,561 were included in NoCH Group and 278 in CH Group. Surgical revision of haemostasis was performed in 70 (25.18%) patients. The overall incidence of postoperative cervical haematoma was 3.15% (0.79% for cervical haematomas requiring surgical revision of haemostasis, and 2.35% for those managed conservatively). The timing of onset of cervical haematomas requiring surgical revision of haemostasis was within six hours after the end of the operation in 52 (74.28%) patients. Readmission was necessary in 3 (1.08%) cases. At multivariate analysis, male sex (P < 0.001), older age (P < 0.001), higher BMI (P = 0.021), unilateral lateral neck dissection (P < 0.001), drain placement (P = 0.007), and shorter operative times (P < 0.001) were found to be independent risk factors for cervical haematoma.Conclusions Based on our findings, we believe that patients with the identified risk factors should be closely monitored in the postoperative period, particularly during the first six hours after the operation, and excluded from outpatient surgery

A photoelectric polarimeter for XEUS: a new window in x-ray sky

XEUS is a large area telescope aiming to rise X-ray Astronomy to the level of Optical Astronomy in terms of collecting areas. It will be based on two satellites, locked on a formation flight, one with the optics, one with the focal plane. The present design of the focal plane foresees, as an auxiliary instrument, the inclusion of a Polarimeter based on a Micropattern Chamber. We show how such a device is capable to solve open problems on many classes of High Energy Astrophysics objects and to use X-ray sources as a laboratory for a substantial progress on Fundamental Physics.Comment: 12 pages, 7 figure

POLARIX: a small mission of x-ray polarimetry

X-Ray Polarimetry can be now performed by using a Micro Pattern Gas Chamber in the focus of a telescope. It requires large area optics for most important scientific targets. But since the technique is additive a dedicated mission with a cluster of small telescopes can perform many important measurements and bridge the 40 year gap between OSO-8 data and future big telescopes such as XEUS. POLARIX has been conceived as such a pathfinder. It is a Small Satellite based on the optics of JET-X. Two telescopes are available in flight configuration and three more can be easily produced starting from the available superpolished mandrels. We show the capabilities of such a cluster of telescopes each equipped with a focal plane photoelectric polarimeter and discuss a few alternative solutions.Comment: 9 pages, 5 figure

PixDD: a multi-pixel silicon drift detector for high-throughput spectral-timing studies

The Pixelated silicon Drift Detector (PixDD) is a two-dimensional multi-pixel X-ray sensor based on the technology of Silicon Drift Detectors, designed to solve the dead time and pile-up issues of photon-integrating imaging detectors. Read out by a two-dimensional self-triggering Application-Specific Integrated Circuit named RIGEL, to which the sensor is bump-bonded, it operates in the 0:5 — 15 keV energy range and is designed to achieve single-photon sensitivity and good spectroscopic capabilities even at room temperature or with mild cooling (< 150 eV resolution at 6 keV at 0 °C). The paper reports on the design and performance tests of the 128-pixel prototype of the fully integrated system