Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

A note on bandits with a twist

Abstract. A variant of the multi-armed bandit problem was recently introduced by Dimitriu, Tetali and Winkler. For this model (and a mild generalization) we propose faster algorithms to compute the Gittins index. The indexability of such models follows from earlier work of Nash on generalized bandits. Key words. Multiarmed bandit problem, generalized bandit problem, stochastic scheduling, priority rule, Gittins index, game AMS subject classifications. 60J10, 66C99, 60G40, 90B35, 90C40 1. Introduction. Th

Pricing strategies and service differentiation in queues — A profit maximization perspective

We consider the problem of pricing and scheduling the customers arriving at a service facility, with the objective of maximizing the profits of the facility, when the value of service and time-sensitivity of a customer are his private information. First we consider the ‘discrete types ’ problem where each customer belongs to one of N types, type i being characterized by its value for service Ri and cost of waiting per unit time ci. For the special case when Ri ci is decreasing in ci, we characterize the structure of the optimal pricing-scheduling policy and design a polynomial-time algorithm to find it. We then analyze the same problem under the additional restriction of at most m different levels of service, characterize the optimal pricing-scheduling policy, and provide an efficient way to find it. Finally, we consider the case where the types of customers form a continuum and the customers have a generalized delay cost structure. Using the insights from the discrete types case, we characterize the conditions under which the optimal mechanism schedules the customers according to the cµ rule

Cooperation in Queues ∗

A set of agents arrive simultaneously to a service facility. Each agent requires the facility for a certain length of time and incurs a cost for each unit of time spent in queue. Attached to each agent is an index, which is the ratio of her waiting cost rate to processing time. Efficiency dictates that the agents be served in decreasing order of their indices. If monetary compensations are disallowed, fairness suggests that agents be served in a random order, each ordering of the agents being equally likely. The efficient ordering is unfair to agents with low indices; the random service order is typically extremely inefficient. It is well-known that this gap can be bridged by using monetary compensations. This paper is motivated by the need to design compensation schemes that are fair to all the agents. Assuming quasi-linear preferences, we find money transfers for the efficient ordering of the agents so that every coalition of agents is at least as well off in the proposed solution as they are in the random service order. To that end, we propose two solution concepts (RP and CRP core), which serve to place upper bounds on the cost share of any coalition of agents. The solutions differ in the definition of the expected worth of a coalition, when the agents are served in a random order. A detailed study of these two concepts as well as their compatibility with other fairness criteria are the main focus of this paper. We show that the RP core is not convex, and that the CRP core is. Furthermore, we show that standard solution concepts like the Shapley solution (of a related game) and the equal gains solution are also in the CRP core. We describe an efficient algorithm to find the equal costs solution in this core. Finally, we axiomatically characterize the Shapley solution

Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study (vol 46, pg 2021, 2022)

N/

Global attitudes in the management of acute appendicitis during COVID-19 pandemic: ACIE Appy Study

Background: Surgical strategies are being adapted to face the COVID-19 pandemic. Recommendations on the management of acute appendicitis have been based on expert opinion, but very little evidence is available. This study addressed that dearth with a snapshot of worldwide approaches to appendicitis. Methods: The Association of Italian Surgeons in Europe designed an online survey to assess the current attitude of surgeons globally regarding the management of patients with acute appendicitis during the pandemic. Questions were divided into baseline information, hospital organization and screening, personal protective equipment, management and surgical approach, and patient presentation before versus during the pandemic. Results: Of 744 answers, 709 (from 66 countries) were complete and were included in the analysis. Most hospitals were treating both patients with and those without COVID. There was variation in screening indications and modality used, with chest X-ray plus molecular testing (PCR) being the commonest (19\ub78 per cent). Conservative management of complicated and uncomplicated appendicitis was used by 6\ub76 and 2\ub74 per cent respectively before, but 23\ub77 and 5\ub73 per cent, during the pandemic (both P < 0\ub7001). One-third changed their approach from laparoscopic to open surgery owing to the popular (but evidence-lacking) advice from expert groups during the initial phase of the pandemic. No agreement on how to filter surgical smoke plume during laparoscopy was identified. There was an overall reduction in the number of patients admitted with appendicitis and one-third felt that patients who did present had more severe appendicitis than they usually observe. Conclusion: Conservative management of mild appendicitis has been possible during the pandemic. The fact that some surgeons switched to open appendicectomy may reflect the poor guidelines that emanated in the early phase of SARS-CoV-2