We use Open Geospace General Circulation Model global MHD simulations to study the nightside magnetospheric, magnetotail, and ionospheric responses to interplanetary (IP) fast forward shocks. Three ...cases are presented in this study: two inclined oblique shocks, hereafter IOS‐1 and IOS‐2, where the latter has a Mach number twice stronger than the former. Both shocks have impact angles of 30° in relation to the Sun‐Earth line. Lastly, we choose a frontal perpendicular shock, FPS, whose shock normal is along the Sun‐Earth line, with the same Mach number as IOS‐1. We find that, in the IOS‐1 case, due to the north‐south asymmetry, the magnetotail is deflected southward, leading to a mild compression. The geomagnetic activity observed in the nightside ionosphere is then weak. On the other hand, in the head‐on case, the FPS compresses the magnetotail from both sides symmetrically. This compression triggers a substorm allowing a larger amount of stored energy in the magnetotail to be released to the nightside ionosphere, resulting in stronger geomagnetic activity. By comparing IOS‐2 and FPS, we find that, despite the IOS‐2 having a larger Mach number, the FPS leads to a larger geomagnetic response in the nightside ionosphere. As a result, we conclude that IP shocks with similar upstream conditions, such as magnetic field, speed, density, and Mach number, can have different geoeffectiveness, depending on their shock normal orientation.
Key Point
Investigation of the impact shock angles in their geoeffectiveness
Summary
The aim of this systematic review was to develop recommendations for the management of postoperative pain after primary elective total hip arthroplasty, updating the previous ...procedure‐specific postoperative pain management (PROSPECT) guidelines published in 2005 and updated in July 2010. Randomised controlled trials and meta‐analyses published between July 2010 and December 2019 assessing postoperative pain using analgesic, anaesthetic, surgical or other interventions were identified from MEDLINE, Embase and Cochrane databases. Five hundred and twenty studies were initially identified, of which 108 randomised trials and 21 meta‐analyses met the inclusion criteria. Peri‐operative interventions that improved postoperative pain include: paracetamol; cyclo‐oxygenase‐2‐selective inhibitors; non‐steroidal anti‐inflammatory drugs; and intravenous dexamethasone. In addition, peripheral nerve blocks (femoral nerve block; lumbar plexus block; fascia iliaca block), single‐shot local infiltration analgesia, intrathecal morphine and epidural analgesia also improved pain. Limited or inconsistent evidence was found for all other approaches evaluated. Surgical and anaesthetic techniques appear to have a minor impact on postoperative pain, and thus their choice should be based on criteria other than pain. In summary, the analgesic regimen for total hip arthroplasty should include pre‐operative or intra‐operative paracetamol and cyclo‐oxygenase‐2‐selective inhibitors or non‐steroidal anti‐inflammatory drugs, continued postoperatively with opioids used as rescue analgesics. In addition, intra‐operative intravenous dexamethasone 8–10 mg is recommended. Regional analgesic techniques such as fascia iliaca block or local infiltration analgesia are recommended, especially if there are contra‐indications to basic analgesics and/or in patients with high expected postoperative pain. Epidural analgesia, femoral nerve block, lumbar plexus block and gabapentinoid administration are not recommended as the adverse effects outweigh the benefits. Although intrathecal morphine 0.1 mg can be used, the PROSPECT group emphasises the risks and side‐effects associated with its use and provides evidence that adequate analgesia may be achieved with basic analgesics and regional techniques without intrathecal morphine.
요약
이 체계적 문헌 고찰의 목적은 2005년에 출판되고 2010년 7월에 업데이트된 시술별로 특화 된 수 술 후 통 증 관 리 (PROSPECT)의 이전 지침을 업데이트하여 인공 고관절 전치 환술 후의 통증 관리에 대한 권고사항을 개발하는 것이었다. 진통제, 마취, 수술 또는 다른 중재를 사용하고 수술 후 통증을 평가한, 2010년 7월과 2019년 12월 사이에 출판된 무작위 대조 시험들과 메타분석들을 MEDLINE, Embase, Cochrane 데이 터베이스로부터 검색하였다. 일차적으로 520건의 연구가 확인 되었고, 그중 108건의 무작위 시험과 21건의 메타분석이 기준 을 충족하였다. 수술 후 통증을 개선한 주술기 중재들은 파라 세타몰(paracetamol), 사이클로옥시게나제‐2 (COX‐2) 선택 적 억제제, 비스테로이드성 소염제, 덱사메타손(dexametha‐ sone) 정맥 주입 등이 있다. 또한, 말초신경차단(대퇴신경차 단, 요추신경총차단, 장골근막차단), 일회성 국소침윤마취, 경 막내 모르핀과 경막외 진통제 투여도 통증을 개선시켰다. 이 외에 평가된 다른 모든 진통 방법들에 대해서는 증거가 불충 분하였다. 수술과 마취 방법들이 수술 후 통증에 미치는 영향 은 미미한 것으로 보이므로, 이들의 선택은 통증 이외 기준에 따라 이루어져야 한다. 요약하면, 인공 고관절 전치환술을 위 한 진통 요법은 수술 전 또는 수술 중 파라세타몰과 사이클로 옥시제나제‐2 선택적 억제제 또는 비스테로이드성 소염제를 포함해야 하며, 수술 후에는 이들의 지속적인 복용 및 구조 진통 요법으로 아편유사제 사용이 동반되어야 한다. 또한, 수 술 중 8‐10 mg의 덱사메타손 정맥 주사가 권장된다. 특히 기 본 진통제에 대한 금기사항이 있거나 수술 후 강한 통증이 예 상되는 환자들의 경우, 장골근막차단이나 국소침윤마취와 같 은 부위 진통 기술들이 권장된다. 경막외 진통제, 대퇴신경차 단, 요추신경총차단과 가바펜티노이드(gabapentinoid) 투여 는 부작용이 이점보다 크기 때문에 권장되지 않는다. 경막내 모르핀 0.1 mg이 사용될 수는 있지만, PROSPECT 그룹은 이 러한 사용과 관련된 위험과 부작용들을 강조하고, 경막내 모 르핀 없이도 기본적 진통제와 부위 진통 기법들로 충분한 진 통이 이루어질 수 있다는 증거를 제공한다.
Kelvin-Helmholtz Instability is ubiquitous at Earth's magnetopause and plays an important role in plasma entry into the magnetosphere during northward interplanetary magnetic fields. Here, using one ...solar cycle of data from NASA THEMIS (Time History of Events and Macro scale Interactions during Substorms) and MMS (Magnetospheric Multiscale) missions, we found that KHI occurrence rates show seasonal and diurnal variations with the rate being high near the equinoxes and low near the solstices. The instability depends directly on the Earth's dipole tilt angle. The tilt toward or away from the Sun explains most of the seasonal and diurnal variations, while the tilt in the plane perpendicular to the Earth-Sun line explains the difference between the equinoxes. The results reveal the critical role of dipole tilt in modulating KHI across the magnetopause as a function of time, highlighting the importance of Sun-Earth geometry for solar wind-magnetosphere interaction and for space weather.
Summary
Caesarean section is associated with moderate‐to‐severe postoperative pain, which can influence postoperative recovery and patient satisfaction as well as breastfeeding success and ...mother‐child bonding. The aim of this systematic review was to update the available literature and develop recommendations for optimal pain management after elective caesarean section under neuraxial anaesthesia. A systematic review utilising procedure‐specific postoperative pain management (PROSPECT) methodology was undertaken. Randomised controlled trials published in the English language between 1 May 2014 and 22 October 2020 evaluating the effects of analgesic, anaesthetic and surgical interventions were retrieved from MEDLINE, Embase and Cochrane databases. Studies evaluating pain management for emergency or unplanned operative deliveries or caesarean section performed under general anaesthesia were excluded. A total of 145 studies met the inclusion criteria. For patients undergoing elective caesarean section performed under neuraxial anaesthesia, recommendations include intrathecal morphine 50–100 µg or diamorphine 300 µg administered pre‐operatively; paracetamol; non‐steroidal anti‐inflammatory drugs; and intravenous dexamethasone administered after delivery. If intrathecal opioid was not administered, single‐injection local anaesthetic wound infiltration; continuous wound local anaesthetic infusion; and/or fascial plane blocks such as transversus abdominis plane or quadratus lumborum blocks are recommended. The postoperative regimen should include regular paracetamol and non‐steroidal anti‐inflammatory drugs with opioids used for rescue. The surgical technique should include a Joel‐Cohen incision; non‐closure of the peritoneum; and abdominal binders. Transcutaneous electrical nerve stimulation could be used as analgesic adjunct. Some of the interventions, although effective, carry risks, and consequentially were omitted from the recommendations. Some interventions were not recommended due to insufficient, inconsistent or lack of evidence. Of note, these recommendations may not be applicable to unplanned deliveries or caesarean section performed under general anaesthesia.
Summary
Video‐assisted thoracoscopic surgery has become increasingly popular due to faster recovery times and reduced postoperative pain compared with thoracotomy. However, analgesic regimens for ...video‐assisted thoracoscopic surgery vary significantly. The goal of this systematic review was to evaluate the available literature and develop recommendations for optimal pain management after video‐assisted thoracoscopic surgery. A systematic review was undertaken using procedure‐specific postoperative pain management (PROSPECT) methodology. Randomised controlled trials published in the English language, between January 2010 and January 2021 assessing the effect of analgesic, anaesthetic or surgical interventions were identified. We retrieved 1070 studies of which 69 randomised controlled trials and two reviews met inclusion criteria. We recommend the administration of basic analgesia including paracetamol and non‐steroidal anti‐inflammatory drugs or cyclo‐oxygenase‐2‐specific inhibitors pre‐operatively or intra‐operatively and continued postoperatively. Intra‐operative intravenous dexmedetomidine infusion may be used, specifically when basic analgesia and regional analgesic techniques could not be given. In addition, a paravertebral block or erector spinae plane block is recommended as a first‐choice option. A serratus anterior plane block could also be administered as a second‐choice option. Opioids should be reserved as rescue analgesics in the postoperative period.
Summary
Rebound pain after brachial plexus block resolution and development of long‐lasting pain are problems associated with volar plate fixation for distal radius fractures. The aim of this ...double‐blind study was to evaluate the effect of a single prophylactic intravenous dose of dexamethasone in this setting. The primary endpoint was highest pain score during the first 24 hours after surgery. We included 51 adults of ASA physical status 1–2 due to undergo planned acute fixation of the radius. All received premedication with oral paracetamol and etoricoxib, and a pre‐operative brachial plexus block with ropivacaine. Patients were randomly allocated into two groups: a dexamethasone group receiving 16 mg dexamethasone intravenously at start of surgery and a control group receiving 4 ml saline. After surgery, all patients received fixed doses of paracetamol, etoricoxib and oxycodone, with further oxycodone added as needed in the first 48 hours. Pain, analgesic consumption and daily function were registered at predefined times up to 1 year after surgery. Median (IQR range) worst pain score in the first 24 hours, as assessed by verbal numeric rating scale (0–10), was 4 (2‐6 0–7) in the dexamethasone group compared with 8 (5–8 2–10) in the placebo group (p < 0.001). Average pain score, 2 (1–4 0–5) vs. 5 (3–6 0–8), p = 0.001 and rescue oxycodone consumption, 5 (0‐10 0‐35) mg vs. 10 (5‐15 0‐50) mg, p = 0.037), respectively, were both significantly lower in the dexamethasone group compared with control from 8 to 24 hours. Brachial plexus block duration was 69% longer in the dexamethasone group, 21.5 (19.1‐23.4 12.9‐24.1) hours vs. 12.7 (11.9‐15.3 7.4‐26.6) hours, p < 0.001. Two patients (9%) in the dexamethasone group compared with 12 (50%) in the placebo group experienced worst pain scores of 8‐10 during the first 36 hours (p = 0.002). At 3 and 7 days postoperatively, there were no significant differences between groups for pain scores or opioid consumption. At 6 months, 27 patients (57%) reported pain at the site of surgery, with significantly higher average pain score (p = 0.024) in the placebo group. At 1 year, two patients in the dexamethasone group reported pain compared with 10 in the placebo group (p = 0.015), and worst pain score was significantly higher in the placebo group (p = 0.018). We conclude that intravenous dexamethasone improves early postoperative analgesia and may also improve clinical outcomes after 6 and 12 months.
Plasma sheet injections associated with low flux tube entropy bubbles have been found to be the primary means of mass transport from the plasma sheet to the inner magnetosphere. This phenomenon has ...been primarily studied with satellite data and stand‐alone ring current models with artificial boundary conditions. This study introduces a new two‐way coupling between a kinetic ring current model (Rice Convection Model, or RCM) and a global magnetosphere MHD model (Open Geospace General Circulation Model, or OpenGGCM). Multiple geomagnetic storms and one period of quiet are modeled to track and characterize inward flow behavior. Simulations show that (1) there is a clear association of plasma sheet injections with bubbles, (2) the majority of inward plasma transport in the magnetotail beyond 6.6 RE is due to bubbles, regardless of storm activity, and (3) the average peak velocity of injections is higher for increasing downtail distances, stronger storms (when compared with storms having similar drivers), and storms driven by corotating interaction regions (when compared with coronal mass ejection‐driven storms of similar strength).
Plain Language Summary
Disturbances in the solar wind, most notably coronal mass ejections from the Sun, impact the plasma environment within the Earth's magnetosphere, the region where Earth's geomagnetic field dominates. This so‐called “space weather” transfers energy and plasma into the magnetosphere, which ultimately affects the near‐Earth plasma environment, or “inner magnetosphere.” Plasma is injected into this region from the nightside magnetosphere, or magnetotail, through a combination of steady and transient injections. There is significant debate about the relative importance of these processes, and the character of the injections themselves. In this study, we use simulations of the global magnetosphere to investigate transient injections to determine their relative importance in transporting plasma into the inner magnetosphere as well as the effect that different types of solar wind disturbances have. We find that transient injections are responsible for the vast majority of the plasma injected into the inner magnetosphere and that the velocity of these injections is dependent on the strength of the geomagnetic storm response and the type of solar wind disturbance.
Key Points
There is a clear association of plasma sheet injections with bubbles
The majority of inward plasma transport in the magnetotail beyond geosynchronous orbit is due to bubbles, regardless of storm activity
The average peak velocity of injections is higher for increasing downtail distances, stronger storms, and storms driven by CIRs
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