Applying MILP-based algorithms to automated job-shop scheduling problems in aircraft-part manufacturing

This work presents efficient algorithms based on Mixed-Integer Linear Programming (MILP) for complex job-shop scheduling problems raised in Automated Manufacturing Systems. The aim of this work is to find alternative solution approaches of production and transportation operations in a multi-product multistage production process that can be used to solve industrial-scale problems with reasonable computational effort. The MILP model developed must take into account; dissimilar recipes, single unit per production stage, re-entrant flows, sequence- dependent free transferring times and load transfer movements in a single automated material-handling device. In addition, logical-based strategies are proposed to iteratively find and improve the solutions generated over time. These approaches were tested in different real-world problems appeared in the surfacetreatment process of metal components in aircraft manufacturing industry.Sociedad Argentina de Informática e Investigación Operativ

Applying MILP-based algorithms to automated job-shop scheduling problems in aircraft-part manufacturing

This work presents efficient algorithms based on Mixed-Integer Linear Programming (MILP) for complex job-shop scheduling problems raised in Automated Manufacturing Systems. The aim of this work is to find alternative solution approaches of production and transportation operations in a multi-product multistage production process that can be used to solve industrial-scale problems with reasonable computational effort. The MILP model developed must take into account; dissimilar recipes, single unit per production stage, re-entrant flows, sequence- dependent free transferring times and load transfer movements in a single automated material-handling device. In addition, logical-based strategies are proposed to iteratively find and improve the solutions generated over time. These approaches were tested in different real-world problems appeared in the surfacetreatment process of metal components in aircraft manufacturing industry.Sociedad Argentina de Informática e Investigación Operativ

Applying MILP-based algorithms to automated job-shop scheduling problems in aircraft-part manufacturing

This work presents efficient algorithms based on Mixed-Integer Linear Programming (MILP) for complex job-shop scheduling problems raised in Automated Manufacturing Systems. The aim of this work is to find alternative solution approaches of production and transportation operations in a multi-product multistage production process that can be used to solve industrial-scale problems with reasonable computational effort. The MILP model developed must take into account; dissimilar recipes, single unit per production stage, re-entrant flows, sequence- dependent free transferring times and load transfer movements in a single automated material-handling device. In addition, logical-based strategies are proposed to iteratively find and improve the solutions generated over time. These approaches were tested in different real-world problems appeared in the surfacetreatment process of metal components in aircraft manufacturing industry.Sociedad Argentina de Informática e Investigación Operativ

Managing daily surgery schedules in a teaching hospital: a mixed-integer optimization approach

Background: This study examined the daily surgical scheduling problem in a teaching hospital. This problem relates to the use of multiple operating rooms and different types of surgeons in a typical surgical day with deterministic operation durations (preincision, incision, and postincision times). Teaching hospitals play a key role in the health-care system; however, existing models assume that the duration of surgery is independent of the surgeon's skills. This problem has not been properly addressed in other studies. We analyze the case of a Spanish public hospital, in which continuous pressures and budgeting reductions entail the more efficient use of resources. Methods: To obtain an optimal solution for this problem, we developed a mixed-integer programming model and user-friendly interface that facilitate the scheduling of planned operations for the following surgical day. We also implemented a simulation model to assist the evaluation of different dispatching policies for surgeries and surgeons. The typical aspects we took into account were the type of surgeon, potential overtime, idling time of surgeons, and the use of operating rooms. Results: It is necessary to consider the expertise of a given surgeon when formulating a schedule: such skill can decrease the probability of delays that could affect subsequent surgeries or cause cancellation of the final surgery. We obtained optimal solutions for a set of given instances, which we obtained through surgical information related to acceptable times collected from a Spanish public hospital. Conclusions: We developed a computer-aided framework with a user-friendly interface for use by a surgical manager that presents a 3-D simulation of the problem. Additionally, we obtained an efficient formulation for this complex problem. However, the spread of this kind of operation research in Spanish public health hospitals will take a long time since there is a lack of knowledge of the beneficial techniques and possibilities that operational research can offer for the health-care system

Patient safety walkrounds with hospital managers: a tool for improving the care of critical patients

Introducción y Objetivos: 1) Describir el proceso de implantación de las Rondas de Seguridad (RS) con Directivos en el área de Cuidados Intensivos de un hospital de tercer nivel; 2) Analizar si hubo diferencias entre las RS en la Unidad de Cuidados Intensivos de adultos (UCI) y la Unidad de Cuidados Intensivos pediátrica (UCIp); 3) Conocer las opiniones de los participantes sobre la herramienta utilizada. Metodología: Estudio analítico longitudinal realizado entre 2009 y 2011. Se utilizó una hoja de registro compuesta por 6 ítems: 1) Presencia de pulsera identificativa; 2) Apósitos de las vías en buen estado; 3) Cabecera de la cama elevada a 30º; 4) Colchón adaptado a paciente con úlcera por presión; 5) Hoja de tratamiento médico sin dudas para enfermería y 6) Hoja de Objetivos Diarios cubierta. Se empleó el estadístico U-Mann Whitney para muestras no paramétricas. Resultados: Se observaron un total de 167 pacientes en 7 RS. La inicial de la UCI los ítems “colchón para paciente con úlceras por presión” y “hoja de objetivos diarios cubierta” registraban un cumplimiento inferior al 60%. En el caso de la UCIp se encontró el 0% de cumplimiento para la pulsera identificativa. Hubo diferencias estadísticamente significativas entre la UCI y la UCIp para los ítems anteriormente citados. Conclusión: Las RS con Directivos aplicadas a las UCI del Hospital Universitario Central de Asturias mejoraron aspectos importantes de Seguridad del Paciente. La implicación de los Directivos fue lo mejor valorado por parte de los profesionales y garantizó el éxito en la implantación de la herramienta.Objectives: 1) To describe the process of implementation of walkrounds with hospital managers in the Intensive Care Unit (ICU) at a tertiary hospital ; 2) To examine whether there were differences between the WR in the Adult Intensive Care Unit (AICU) and the Pediatric Intensive Care Unit (PICU ); 3) To know the opinion of the participants about the tool. Methodology: It is an analytic and longitudinal study done between 2009 and 2011. It was used a sheet with 6 items: 1) Presence of wristband ; 2) Dressings roads in good condition; 3) Headboard at 30º; 4) Special mattress adapted to patients with pressure ulcers ; 5 ) Sheet for medical treatments without any doubts for nurses and 6) Daily goal sheet fulfilled. It was used Statistical U Mann – Whitney for nonparametric samples. Results: A total of 167 patients were seen in 7. walkrounds At the beginning, items “mattress for patients with pressure ulcers” and “daily goal sheet fulfilled” had less than 60% of compliance in AICU. For the PICU, we found 0 % of compliance in the presence of wristband. There were statistically significant differences between the AICU and the PICU for those items. Conclusion: Walkrounds with hospital managers applied to ICUs at our hospital improved important aspects of patient safety. The involvement of hospital managers was the most important thing for the rest of health care workers and it ensured the successful implementation of the tool

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock, 2012

OBJECTIVE: To provide an update to the "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," last published in 2008. DESIGN: A consensus committee of 68 international experts representing 30 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict of interest policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independent of any industry funding. A stand-alone meeting was held for all subgroup heads, co- and vice-chairs, and selected individuals. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development. METHODS: The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations as strong (1) or weak (2). The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized. Recommendations were classified into three groups: (1) those directly targeting severe sepsis; (2) those targeting general care of the critically ill patient and considered high priority in severe sepsis; and (3) pediatric considerations. RESULTS: Key recommendations and suggestions, listed by category, include: early quantitative resuscitation of the septic patient during the first 6 h after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm a potential source of infection (UG); administration of broad-spectrum antimicrobials therapy within 1 h of the recognition of septic shock (1B) and severe sepsis without septic shock (1C) as the goal of therapy; reassessment of antimicrobial therapy daily for de-escalation, when appropriate (1B); infection source control with attention to the balance of risks and benefits of the chosen method within 12 h of diagnosis (1C); initial fluid resuscitation with crystalloid (1B) and consideration of the addition of albumin in patients who continue to require substantial amounts of crystalloid to maintain adequate mean arterial pressure (2C) and the avoidance of hetastarch formulations (1B); initial fluid challenge in patients with sepsis-induced tissue hypoperfusion and suspicion of hypovolemia to achieve a minimum of 30 mL/kg of crystalloids (more rapid administration and greater amounts of fluid may be needed in some patients (1C); fluid challenge technique continued as long as hemodynamic improvement is based on either dynamic or static variables (UG); norepinephrine as the first-choice vasopressor to maintain mean arterial pressure ≥65 mmHg (1B); epinephrine when an additional agent is needed to maintain adequate blood pressure (2B); vasopressin (0.03 U/min) can be added to norepinephrine to either raise mean arterial pressure to target or to decrease norepinephrine dose but should not be used as the initial vasopressor (UG); dopamine is not recommended except in highly selected circumstances (2C); dobutamine infusion administered or added to vasopressor in the presence of (a) myocardial dysfunction as suggested by elevated cardiac filling pressures and low cardiac output, or (b) ongoing signs of hypoperfusion despite achieving adequate intravascular volume and adequate mean arterial pressure (1C); avoiding use of intravenous hydrocortisone in adult septic shock patients if adequate fluid resuscitation and vasopressor therapy are able to restore hemodynamic stability (2C); hemoglobin target of 7-9 g/dL in the absence of tissue hypoperfusion, ischemic coronary artery disease, or acute hemorrhage (1B); low tidal volume (1A) and limitation of inspiratory plateau pressure (1B) for acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure (PEEP) in ARDS (1B); higher rather than lower level of PEEP for patients with sepsis-induced moderate or severe ARDS (2C); recruitment maneuvers in sepsis patients with severe refractory hypoxemia due to ARDS (2C); prone positioning in sepsis-induced ARDS patients with a PaO (2)/FiO (2) ratio of ≤100 mm Hg in facilities that have experience with such practices (2C); head-of-bed elevation in mechanically ventilated patients unless contraindicated (1B); a conservative fluid strategy for patients with established ARDS who do not have evidence of tissue hypoperfusion (1C); protocols for weaning and sedation (1A); minimizing use of either intermittent bolus sedation or continuous infusion sedation targeting specific titration endpoints (1B); avoidance of neuromuscular blockers if possible in the septic patient without ARDS (1C); a short course of neuromuscular blocker (no longer than 48 h) for patients with early ARDS and a PaO (2)/FI O (2) 180 mg/dL, targeting an upper blood glucose ≤180 mg/dL (1A); equivalency of continuous veno-venous hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1B); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding in patients with bleeding risk factors (1B); oral or enteral (if necessary) feedings, as tolerated, rather than either complete fasting or provision of only intravenous glucose within the first 48 h after a diagnosis of severe sepsis/septic shock (2C); and addressing goals of care, including treatment plans and end-of-life planning (as appropriate) (1B), as early as feasible, but within 72 h of intensive care unit admission (2C). Recommendations specific to pediatric severe sepsis include: therapy with face mask oxygen, high flow nasal cannula oxygen, or nasopharyngeal continuous PEEP in the presence of respiratory distress and hypoxemia (2C), use of physical examination therapeutic endpoints such as capillary refill (2C); for septic shock associated with hypovolemia, the use of crystalloids or albumin to deliver a bolus of 20 mL/kg of crystalloids (or albumin equivalent) over 5-10 min (2C); more common use of inotropes and vasodilators for low cardiac output septic shock associated with elevated systemic vascular resistance (2C); and use of hydrocortisone only in children with suspected or proven "absolute"' adrenal insufficiency (2C). CONCLUSIONS: Strong agreement existed among a large cohort of international experts regarding many level 1 recommendations for the best care of patients with severe sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for this important group of critically ill patients

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries