1,720,990 research outputs found
Measurements 2: space-time measurements of freak waves
No full textThis chapter focuses on the observation of freak waves made from instruments capable of retrieving the 3-D geometry of the evolving wave fields. The basis for identifying freak waves in the 2-D space and time is described, and the present state of the art of the sensors and related hardware is summarized. Also briefly discussed is the statistical basis for interpreting space-time freak wave events. Examples of measured freak waves complete the chapter
The 29 October 2018 storm in Northern Italy: Its multiple actions in the Ligurian Sea
No full textWe analyse the storm that hit the Ligurian Sea in the afternoon of 29 October 2018. Although not a historical extreme, the event was unique in itself for the superposition of an explosive cyclogenesis on a preexisting southerly flow. Combined with the general meteorological pattern, this led in the range of a few hours to quite different, similarly severe wind and wave conditions. The storm has been analysed using both the models of the European Centre for Medium-Range Weather Forecasts and a nested WRF + WW3 one. The orography of Corsica has been instrumental in shaping the local fields. The storm, and in particular the cyclogenesis, were well forecast. However, as evidenced especially by the different ensemble members, minor differences in the position of the minimum could lead to substantial differences at specific locations, also where major damages were reported
SUGAMMADEX versus neostigmine after ROCURONIUM continuous infusion in patients undergoing liver transplantation
Full text linkBackground: Rapid neuromuscular block reversal at the end of major abdominal surgery is recommended to avoid any postoperative residual block. To date, no study has evaluated sugammadex performance after rocuronium administration in patients undergoing liver transplantation. This is a randomized controlled trial with the primary objective of assessing the neuromuscular transmission recovery time obtained with sugammadex versus neostigmine after rocuronium induced neuromuscular blockade in patients undergoing orthotopic liver transplantation. Methods: The TOF-Watch SX®, calibrated and linked to a portable computer equipped with TOF-Watch SX Monitor Software®, was used to monitor and record intraoperative neuromuscular block maintained with a continuous infusion of rocuronium. Anaesthetic management was standardized as per our institution's internal protocol. At the end of surgery, neuromuscular moderate block reversal was obtained by administration of 2 mg/kg of sugammadex or 50 mcg/kg of neostigmine (plus 10 mcg/kg of atropine). Results: Data from 41 patients undergoing liver transplantation were analysed. In this population, recovery from neuromuscular block was faster following sugammadex administration than neostigmine administration, with mean times±SD of 9.4 ± 4.6 min and 34.6 ± 24.9 min, respectively (p < 0.0001). Conclusion: Sugammadex is able to reverse neuromuscular block maintained by rocuronium continuous infusion in patients undergoing liver transplantation. The mean reversal time obtained with sugammadex was significantly faster than that for neostigmine. It is important to note that the sugammadex recovery time in this population was found to be considerably longer than in other surgical settings, and should be considered in clinical practice. Trial registration: ClinicalTrials.gov NCT02697929 (registered 3rd March 2016)
OUR EXPERIENCE OF INCIDENT REPORTING IN ANESTHESIA: EFFECTIVENESS OF AN AWARENESS CAMPAIGN
No full textcarotid vs. aortic velocity time integral and peak velocity to predict fluid responsiveness in mechanically ventilated patients. A comparative study
No full textBACKGROUND: The carotid artery velocity-time integral (cVTI) and the carotid Doppler peak velocity (cDPV), as well as measures of their variation induced by the respiratory cycle, have been proposed as fast and easy to obtain ultrasound measures for assessing fluid responsiveness in intensive care unit patients. To investigate this possibility, we conducted a prospective observational study in hemodynamically unstable patients under mechanical ventilation. METHODS: From May 1 to December 31, 2019, we conducted a prospective observational study involving 50 hemodynamically unstable patients under mechanical ventilation. We obtained a total of 800 Doppler ultrasound measurements from the left common carotid artery and at the level of the aortic annulus in the apical five-chamber view. The two measurements were performed before and after a 7 mL/kg fluid challenge and within the first hour of the onset of hemodynamic instability. The maximum Doppler peak velocity, the minimum Doppler peak velocity, and the maximum and minimum VTI at both the aortic and carotid level were acquired. RESULTS: Twenty-eight (56%) patients showed a ≥15% increase in aoVTI after the fluid challenge, and were therefore identified as “fluid responders”. All Doppler measurements were always significantly greater (P<0.0001) in fluid responders in relation to both carotid and aortic parameters. Good agreement between the above-mentioned measurements was found: Cohen’s kappa coefficient between the carotid and aortic ΔDPV was 0.76 (95% CI 0.58-0.94); and between the Carotid and Aortic ΔVTI it was 0.84 (95% CI 0.68-0.99). CONCLUSIONS: cDPV was found to predict fluid responsiveness in unstable mechanically ventilated patients
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Our Italian experience using lung ultrasound for identification, grading and serial follow-up of severity of lung involvement for management of patients with COVID-19
No full textLung ultrasound (LU) has rapidly become a tool for assessment of patients stricken by the novel coronavirus 2019 (COVID-19). Over the past two and a half months (January, February, and first half of March 2020) we have used this modality for identification of lung involvement along with pulmonary severity in patients with suspected or documented COVID-19 infection. Use of LU has helped us in clinical decision making and reduced the use of both chest x-rays and computed tomography (CT)
On the extreme value statistics of spatio-temporal maximum sea waves under cyclone winds
Full text linkPrinciples of the spatio-temporal statistics are used to investigate the characteristics of short-term/range extreme sea waves and related sea-state parameters under cyclone winds (northern hemisphere). We base our analysis upon consistent stereo-imaging observations of the 3D (2D space + time) sea surface elevation field, and spectral wave model results in the Northwestern Pacific during tropical storm Kong-rey (2018). The focus is on the extreme value analysis of individual maximum sea surface elevations (crest heights) and maximum crest-to-trough wave heights. Results highlight the sea areas around the storm centre where the spatio-temporal highest waves are more likely, and, via scale analysis, the principal mechanisms responsible for the occurrence of extreme conditions in bimodal (composed of wind-sea and swell) and short-crested storm seas. We find that individual waves are the highest to the north-east of the translating cyclone, where sea states are more energetic. However, in the south/south-west of the centre, where opposing wind-sea/swell sea states dominate, directional spread and bound nonlinear interactions are enhanced. In this area, more extreme waves may occur, having the maximum crest and wave heights mean values in excess of 1.3 and 2.1 times the significant wave height, respectively. This set of results provides insights into the role of the dispersive and directional focusing enhanced by nonlinearities up to the second order as an effective mechanism for the formation of extreme waves under cyclone winds. To examine what physical mechanism is behind the generation of extreme waves in different regions around the cyclone, we also explore for comparison areas where nonlinear four-wave interactions are more likely to occur
- …
