Systematic review of the safety and efficacy of foam sclerotherapy for venous disease of the lower limbs

Background: Foam sclerotherapy is a potential treatment for lower limb venous disease. Methods: A systematic review, with no restriction on study design, to assess the safety and efficacy of foam sclerotherapy. Results: 69 studies were included. For serious adverse events including pulmonary embolism and deep vein thrombosis, the median event rates were less than 1%. Median rate for visual disturbance was 1.4%. Median rates for some other adverse events were more common, including headache (4.2%), thrombophlebitis (4.7%), matting/skin staining/pigmentation (17.8%) and pain at the site of injection (25.6%). Median rate for complete occlusion of treated veins was 87.0% and for recurrence or development of new veins was 8.1%. Evidence from meta-analysis for complete occlusion suggests that foam sclerotherapy is associated with a lower rate compared with surgery (RR 0.86, 95% CI 0.67 to 1.10) and a higher rate compared with liquid sclerotherapy (RR 1.39, 95% CI 0.91 to 2.11). However, there was substantial heterogeneity across the studies in the meta-analysis. Conclusion: Serious adverse events were rare. There is insufficient evidence to reliably compare the effectiveness of foam sclerotherapy with other minimally invasive therapies or surgery. Evidence from high quality randomised controlled trials is required.This manuscript is based on a systematic review commissioned and funded by the National Institute for Health and Clinical Excellence (NICE) through its Interventional Procedures Programme. The Health Services Research Unit is supported by a core grant from the Chief Scientist Office of the Scottish Executive Health Department

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Analyzing the performance of asynchronous disk arrays for multimedia retrieval

Due to the periodic nature of media playback, a multimedia server can service multipleclients simultaneouslyby proceeding in rounds, retrieving a fixed number of media units (e.g., video frames) for each client during each round. In this paper, we analyze the performance of a conservative and an aggressive policy for retrieving media units from an asynchronous disk array. In the conservative servicing policy, a server completely retrieves all the required media units during a round prior to initiating the next round. A server employing the aggressive servicing policy, on the other hand, requires the disks to synchronize only over a finite sequence of rounds. We have carried out extensive simulations to measure the effectiveness of the conservative and the aggressive servicing policies on the utilization of asynchronous disk arrays. We present and analyze our simulation results

The Cost of Recovery in Message Logging Protocols

Past research in message logging has focused on studying the relative overhead imposed by pessimistic, optimistic, and causal protocols during failure-free executions. In this paper, we give the first experimental evaluation of the performance of these protocols during recovery. We discover that, if a single failure is to be tolerated, pessimistic and causal protocols perform best, because they avoid rollbacks of correct processes. For multiple failures, however, the dominant factor in determining performance becomes where the recovery information is logged (i.e. at the sender, at the receiver, or replicated at a subset of the processes in the system) rather than when this information is logged (i.e. if logging is synchronous or asynchronous). 1 Introduction Message-logging protocols (for example, [2, 3, 4, 6, 9, 10, 14, 15]) are popular techniques for building systems that can tolerate process crash failures. These protocols are built on the assumption that the state of a process is..

Comparative Evaluation of Server-push and Client-pull Architectures for Multimedia Servers

Realizing a wide range of multimedia services will require the development of high performance, integrated multimedia servers (or file systems) which can efficiently manage the storage, access, and transmission of audio, video, and textual objects. Traditionally storage servers have employed fundamentally different mechanisms for managing the storage and access of each of these objects. Whereas most conventional text file systems employ a client-pull architecture, most video servers proposed in the literature employ a server-push architecture. Hence, the most fundamental question is: what is an appropriate architecture for integrated multimediaservers? In this paper, we take a step towards addressing this question by outlining the qualitative and quantitative differences between the server-push and client-pull architectures. 1 Introduction Recent advances in computing and communication technologies have made it feasible as well as economically viable to provide on-line access to a var..

Egida: An Extensible Toolkit for Low-overhead Fault-tolerance

We discuss the design and implementation of Egida, an object-oriented toolkit designed to support transparent rollback-recovery. Egida exports a simple specification language that can be used to express arbitrary rollback recovery protocols. From this specification, Egida automatically synthesizes an implementation of the specified protocol by glueing together the appropriate objects from an available library of “building blocks”. Egida is extensible and facilitates rapid implementation of rollback recovery protocols with minimal programming effort. We have integrated Egida with the MPICH implementation of the MPI standard. Existing MPI applications can take advantage of Egida without any modifications: fault-tolerance is achieved transparently—all that is needed is a simple re-link of the MPI application with Egida. We demonstrate Egida’s versatility both as a testbed as well as an environment for developing new protocols by generating a few message logging protocols and evaluating their performance with a set of NAS benchmarks on a network of workstations.