scholarly journals Analysis and Optimization of a Combined Make-to-Stock and Make-to-Order Multiproduct Manufacturing System

2009 ◽  
Vol 2009 ◽  
pp. 1-27 ◽  
Author(s):  
Khaled Hadj Youssef ◽  
Christian van Delft ◽  
Yves Dallery
Keyword(s):  
Lead Time ◽  
High Volume ◽  
Service Level ◽  
Time Service ◽  
Inventory Costs ◽  
Make To Order ◽  
End Products ◽  
Low Volume ◽  
Multiproduct Manufacturing ◽  
The Impact

We consider a single-stage multiproduct manufacturing facility producing several end-products for delivery to customers with a required customer lead-time. The end-products can be split in two classes: few products with high volume demands and a large number of products with low-volume demands. In order to reduce inventory costs, it seems efficient to produce the high-volume products according to an MTS policy and the low volume products according to an MTO policy. The purpose of this paper is to analyze and compare the impact of the scheduling policy on the overall inventory costs, under customer lead-time service level constraints. We consider two policies: the classical FIFO policy and a priority policy (PR) which gives priority to low volume products over high volume products. We show that for some range of parameters, the PR rule can significantly outperform the FIFO rule. In these ranges, the service level constraints are satisfied by the PR rule with much lower inventory costs.

scholarly journals Comparison of particular logistic models’ adoption in the Czech Republic

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Petra Vrbová ◽  
Václav Cempírek
Keyword(s):  
Supply Chain ◽  
Czech Republic ◽  
Lead Time ◽  
Logistic Model ◽  
Logistic Models ◽  
Service Level ◽  
Time Service ◽  
The Czech Republic ◽  
Total Cost ◽  
Challenging Tasks

Abstract Managing inventory is considered as one of the most challenging tasks facing supply chain managers and specialists. Decisions related to inventory locations along with level of inventory kept throughout the supply chain have a fundamental impact on the response time, service level, delivery lead-time and the total cost of the supply chain. The main objective of this paper is to identify and analyse the share of a particular logistic model adopted in the Czech Republic (Consignment stock, Buffer stock, Safety stock) and also compare their usage and adoption according to different industries. This paper also aims to specify possible reasons of particular logistic model preferences in comparison to the others. The analysis is based on quantitative survey held in the Czech Republic.

scholarly journals Safety of endovascular therapy for symptomatic intracranial artery stenosis: a national prospective registry

2021 ◽  
pp. svn-2021-000979
Author(s):  
Yabing Wang ◽  
Tao Wang ◽  
Adam Andrew Dmytriw ◽  
Kun Yang ◽  
Liqun Jiao ◽  
...  
Keyword(s):  
Endovascular Therapy ◽  
Real World ◽  
High Volume ◽  
Artery Stenosis ◽  
Arterial Stenosis ◽  
Intracranial Artery ◽  
Moderate Volume ◽  
Intracranial Artery Stenosis ◽  
Low Volume ◽  
The Impact

IntroductionThe safety outcomes of endovascular therapy for intracranial artery stenosis in a real-world stetting are largely unknown. The Clinical Registration Trial of Intracranial Stenting for Patients with Symptomatic Intracranial Artery Stenosis (CRTICAS) was a prospective, multicentre, real-world registry designed to assess these outcomes and the impact of centre experience.Methods1140 severe, symptomatic intracranial arterial stenosis (ICAS) patients treated with endovascular therapy were included from 26 centres, further divided into three groups according to the annual centre volume of intracranial angioplasty and stent placement procedures over 2 years: (1) high volume for ≥25 cases/year; (2) moderate volume for 10–25 cases/year and (3) low volume for <10 cases/year.ResultsThe rate of 30-day stroke, transient ischaemic attack or death was 9.7% (111), with 5.4%, 21.1% and 9.7% in high-volume, moderate-volume and low-volume centres, respectively (p<0.05). Multivariable logistic regression confirmed high-volume centres had a significantly lower primary endpoint compared with moderate-volume centres (OR=0.187, 95% CI: 0.056 to 0.627; p≤0.0001), while moderate-volume and low-volume centres showed no significant difference (p=0.8456).ConclusionCompared with the preceding randomised controlled trials, this real-world, prospective, multicentre registry shows a lower complication rate of endovascular treatment for symptomatic ICAS. Non-uniform utilisation in endovascular technology, institutional experience and patient selection in different volumes of centres may have an impact on overall safety of this treatment.

Institutional volume affects long-term survival following lung transplantation in the USA

2019 ◽  
Vol 56 (2) ◽  
pp. 271-276 ◽  
Author(s):  
Arman Kilic ◽  
Thomas G Gleason ◽  
Hiroshi Kagawa ◽  
Ahmet Kilic ◽  
Ibrahim Sultan
Keyword(s):  
Lung Transplantation ◽  
High Volume ◽  
Term Survival ◽  
Long Term Survival ◽  
Kaplan Meier ◽  
The Usa ◽  
Institutional Volume ◽  
Low Volume ◽  
The Impact

Abstract OBJECTIVES The aim of this study was to evaluate the impact of institutional volume on long-term outcomes following lung transplantation (LTx) in the USA. METHODS Adults undergoing LTx were identified in the United Network for Organ Sharing registry. Patients were divided into equal size tertiles according to the institutional volume. All-cause mortality following LTx was evaluated using the risk-adjusted multivariable Cox regression and the Kaplan–Meier analyses, and compared between these volume cohorts at 3 points: 90 days, 1 year (excluding 90-day deaths) and 10 years (excluding 1-year deaths). Lowess smoothing plots and receiver-operating characteristic analyses were performed to identify optimal volume thresholds associated with long-term survival. RESULTS A total of 13 370 adult LTx recipients were identified. The mean annual centre volume was 33.6 ± 20.1. After risk adjustment, low-volume centres were found to be at increased risk for 90-day mortality, [hazard ratio (HR) 1.56, P < 0.001], 1-year mortality excluding 90-day deaths (HR 1.46, P < 0.001) and 10-year mortality excluding 1-year deaths (HR 1.22, P < 0.001). These findings persisted when the centre volume was modelled as a continuous variable. The Kaplan–Meier analysis also demonstrated significant reductions in survival at each of these time points for low-volume centres (each P < 0.001). The 10-year survival conditional on 1-year survival was 37.4% in high-volume centres vs 28.0% in low-volume centres (P < 0.001). The optimal annual volume threshold for long-term survival was 26 LTx/year. CONCLUSIONS The institutional volume impacts long-term survival following LTx, even after excluding deaths within the first post-transplant year. Identifying the processes of care that lead to longer survival in high-volume centres is prudent.

scholarly journals Trends in hospital procedure volumes for intra-arterial treatment of acute ischemic stroke: results from the paul coverdell national acute stroke program

2020 ◽  
Vol 12 (11) ◽  
pp. 1076-1079
Author(s):  
Ganesh Asaithambi ◽  
Xin Tong ◽  
Kamakshi Lakshminarayan ◽  
Sallyann M Coleman King ◽  
Mary G George
Keyword(s):  
Ischemic Stroke ◽  
Acute Stroke ◽  
Acute Ischemic Stroke ◽  
Patient Outcomes ◽  
High Volume ◽  
Favorable Outcome ◽  
Stroke Registry ◽  
The Usa ◽  
Low Volume ◽  
The Impact

BackgroundRates of intra-arterial revascularization treatments (IAT) for acute ischemic stroke (AIS) are increasing in the USA. Using a multi-state stroke registry, we studied the trend in IAT use among patients with AIS over a period spanning 11 years. We examined the impact of IAT rates on hospital procedure volumes and patient outcome after stroke.MethodsWe used data from the Paul Coverdell National Acute Stroke Program (PCNASP) and explored trends in IAT between 2008 and 2018. Patient outcomes were examined by rates of IAT procedures across hospitals. Specifically, outcomes were compared across low-volume (<15 IAT per year), medium-volume (15–30 IAT per year), and high-volume hospitals (>30 IAT per year). Favorable outcome was defined as discharge to home.ResultsThere were 612 958 patients admitted with AIS to 687 participating hospitals within the PCNASP during this study. Only 2.9% of patients (mean age 68.5 years, 49.3% women) received IAT. The percent of patients with AIS receiving IAT increased from 1% in 2008 to 5.3% in 2018 (p<0.001). The proportion of low-volume hospitals decreased over time (p<0.001), and the proportions of medium-volume (p=0.007) and high-volume hospitals (p<0.001) increased between 2008 and 2018. When compared with medium-volume hospitals, high-volume hospitals had a higher (p<0.0001) and low-volume hospitals had a lower (p<0.0001) percent of patients discharged to home.ConclusionHigh-volume hospitals were associated with a higher rate of favorable outcome. With the increased use of IAT among patients with AIS, the proportion of low-volume hospitals performing IAT significantly decreased.

The Impact of Regionalization of Pancreaticoduodenectomy for Pancreatic Cancer in North Carolina since 2004

2014 ◽  
Vol 80 (6) ◽  
pp. 561-566 ◽  
Author(s):  
Ryan Z. Swan ◽  
David J. Niemeyer ◽  
Ramanathan M. Seshadri ◽  
Kyle J. Thompson ◽  
Amanda Walters ◽  
...  
Keyword(s):  
North Carolina ◽  
Significant Risk ◽  
High Volume ◽  
Major Morbidity ◽  
The North ◽  
Time Period ◽  
Improved Outcomes ◽  
Before And After ◽  
Low Volume ◽  
The Impact

Pancreaticoduodenectomy (PD) carries a significant risk. High-volume centers (HVCs) provide improved outcomes and regionalization is advocated. Rapid regionalization could, however, have detrimental effects. North Carolina has multiple HVCs, including an additional HVC added in late 2006. We investigated regionalization of PD and its effects before, and after, the establishment of this fourth HVC. The North Carolina Hospital Discharge Database was queried for all PDs performed during 2004 to 2006 and 2007 to 2009. Hospitals were categorized by PD volume as: low (one to nine/year), medium (10 to 19/year), and high (20/year or more). Mortality and major morbidity was assessed by comparing volume groups across time periods. Number of PDs for cancer increased 91 per cent (129 to 246 cases) at HVCs, whereas decreasing at low-volume (62 to 58 cases) and medium-volume (80 to 46 cases) centers. Percentage of PD for cancer performed at HVCs increased significantly (47.6 to 70.3%) while decreasing for low- and medium-volume centers ( P < 0.001). Mortality was significantly less at HVCs (2.8%) compared with low-volume centers (10.3%) for 2007 to 2009. Odds ratio for mortality was significantly lower at HVCs during 2004 to 2006 (0.31) and 2007 to 2009 (0.34). Mortality for PD performed for cancer decreased from 6.6 to 4.6 per cent ( P = 0.31). Major morbidity was not significantly different between groups within either time period; however, there was a significant increase in major morbidity at low-volume centers ( P = 0.018). Regionalization of PD for cancer is occurring in North Carolina. Mortality was significantly lower at HVCs, and rapid regionalization has not detracted from the superior outcomes at HVCs.

scholarly journals Influence of Individual Surgeon Volume on Oncological Outcome of Colorectal Cancer Surgery

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Marleen Buurma ◽  
Hidde M. Kroon ◽  
Marlies S. Reimers ◽  
Peter A. Neijenhuis
Keyword(s):  
Colorectal Cancer ◽  
Multivariate Analysis ◽  
Disease Free Survival ◽  
High Volume ◽  
Free Survival ◽  
Significant Difference ◽  
Low Volume ◽  
The Impact ◽  
Disease Free

Background. Surgery performed by a high-volume surgeon improves short-term outcomes. However, not much is known about long-term effects. Therefore we performed the current study to evaluate the impact of high-volume colorectal surgeons on survival.Methods. We conducted a retrospective analysis of our prospectively collected colorectal cancer database between 2004 and 2011. Patients were divided into two groups: operated on by a high-volume surgeon (>25 cases/year) or by a low-volume surgeon (<25 cases/year). Perioperative data were collected as well as follow-up, recurrence rates, and survival data.Results. 774 patients underwent resection for colorectal malignancies. Thirteen low-volume surgeons operated on 453 patients and 4 high-volume surgeons operated on 321 patients. Groups showed an equal distribution for preoperative characteristics, except a higher ASA-classification in the low-volume group. A high-volume surgeon proved to be an independent prognostic factor for disease-free survival in the multivariate analysisP=0.04. Although overall survival did show a significant difference in the univariate analysisP<0.001it failed to reach statistical significance in the multivariate analysisP=0.09.Conclusions. In our study, a higher number of colorectal cases performed per surgeon were associated with longer disease-free survival. Implementing high-volume surgery results in improved long-term outcome following colorectal cancer.

Impact of Surgeon Volume on Incidence of Neck Hematoma after Thyroid and Parathyroid Surgery: Ten Years’ Analysis of Nationwide In-patient Sample Database

2014 ◽  
Vol 80 (10) ◽  
pp. 948-952 ◽  
Author(s):  
Ahmed Dehal ◽  
Ali Abbas ◽  
Mohammed Al-Tememi ◽  
Farabi Hussain ◽  
Samir Johna
Keyword(s):  
High Volume ◽  
International Classification Of Diseases ◽  
Surgeon Volume ◽  
Administrative Database ◽  
Parathyroid Surgery ◽  
Patient Sample ◽  
Surgeon Experience ◽  
Classification Of Diseases ◽  
Low Volume ◽  
The Impact

The study's objective is to examine the impact of surgeon experience on the incidence and the severity of neck hematoma after thyroid and parathyroid surgery using a nationwide database. The Nationwide In-patient Sample is a nationwide clinical and administrative database. We used the International Classification of Diseases, 9th Revision diagnosis and procedures codes to identify adult patients who underwent thyroid and parathyroid surgery and subsequently developed neck hematoma. Patient and hospital characteristics were collected along with surgeon volume to predict patient outcomes. Surgical procedures were stratified into three groups according to surgeon volume: low (less than 10 operations), intermediate (10 to 99), and high (100 or more). We identified 147,344 thyroid and parathyroid surgery performed between 2000 and 2009 nationwide. Overall incidence of postoperative neck hematoma was 1.5 per cent (n = 2210). This was 2.1, 1.4, and 0.9 per cent among procedures performed by low-volume, intermediate-volume, and high-volume surgeons, respectively. After adjusting for other confounders, compared with procedures performed by low-volume surgeons, those performed by intermediate- (odds ratio [OR], 0.7; 95% confidence interval [CI], 0.6 to 0.8; P < 0.01) and high-volume surgeons (OR, 0.5; 95% CI, 0.4 to 0.6; P < 0.01) were less to likely to develop neck hematoma. Surgeon experience is significantly associated with the development of neck hematoma after thyroid and parathyroid surgery.

scholarly journals A High-Volume, Academic Orthopedic Specialty Hospital Provides the Shortest Operative Times in Total Hip Arthroplasty

2021 ◽  
Author(s):  
Stephen G. Zak ◽  
Jenna Bernstein ◽  
Alex Tang ◽  
James Slover ◽  
Ran Schwarzkopf ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Operative Time ◽  
High Volume ◽  
Community Hospitals ◽  
Total Hip ◽  
Revision Tha ◽  
Orthopedic Care ◽  
Low Volume ◽  
The Impact

AbstractOperative time is a potential modifiable target for reducing cost and optimizing efficiency in total hip arthroplasty (THA). Shorter operative times are associated with decreased costs and complications. One proposed solution for reducing operating room (OR) times is to preferentially perform THAs at a higher volume center. The purpose of this study is to investigate the impact of different hospital settings on mean operative time in THA. A retrospective analysis of 7,694 consecutive primary and revision THA cases across four different hospitals was conducted. The hospitals reviewed in this study include a high-volume academic (HVA) orthopedic hospital, a large tertiary, low-volume academic (LVA) center, a high-volume community (HVC) hospital, and a low-volume community (LVC) hospital. Operative times, patient baseline demographics, and procedure classification (inpatient vs. outpatient) were collected. For primary THA, the HVA hospital maintained the statistically lowest total OR times followed by the HVC hospital (155.96 vs. 167.27 minutes, p < 0.0001). The LVC and HVC centers had similar total OR times (175.48 vs. 167.27 minutes, p = 0.578). For revision THA, the LVC center had the shortest total OR time followed by the HVA, LVA, and HVC sites (194.85 vs. 224.69 vs. 244.07 vs. 279.54 minutes). However, there were a larger amount of revision cases performed at our HVA sites than our community hospitals (523 vs. 123 cases). Our HVA hospital specialized in orthopedic care experiences shorter primary THA OR times than community hospitals. These findings suggest that in addition to hospital volume, factors such as specialized staffing, standardized OR protocols, and additional resources affect operative times, making HVA centers better equipped to handle primary THA.

scholarly journals Effective Investment to Reduce Setup Cost in a Mixture Inventory Model Involving Controllable Backorder Rate and Variable Lead Time with a Service Level Constraint

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Hsien-Jen Lin
Keyword(s):  
Cost Reduction ◽  
Lead Time ◽  
Service Level ◽  
Inventory Model ◽  
Optimal Order ◽  
Order Quantity ◽  
Setup Cost ◽  
System Parameters ◽  
Decision Variables ◽  
The Impact

This paper investigates the impact of setup cost reduction on an inventory policy for a continuous review mixture inventory model involving controllable backorder rate and variable lead time with a service level constraint, in which the order quantity, setup cost, and lead time are decision variables. Our objective is to develop an algorithm to determine the optimal order quantity, setup cost, and lead time simultaneously, so that the total expected annual cost incurred has a minimum value. Furthermore, four numerical examples are provided to illustrate the results, and the effects of system parameters are also included for decision making.

Outcomes of transcatheter aortic valve implantations in high-volume or low-volume centres in Germany

Heart ◽  
2020 ◽  
Vol 106 (20) ◽  
pp. 1604-1608
Author(s):  
Vera Oettinger ◽  
Klaus Kaier ◽  
Timo Heidt ◽  
Markus Hortmann ◽  
Dennis Wolf ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Hospital Mortality ◽  
Pacemaker Implantation ◽  
High Volume ◽  
Bleeding Events ◽  
Hospital Outcomes ◽  
Minimum Requirement ◽  
Transcatheter Aortic Valve ◽  
Low Volume ◽  
The Impact

ObjectiveTranscatheter aortic valve implantation (TAVI) is the most common aortic valve replacement in Germany. Since 2015, to ensure high-quality procedures, hospitals in Germany and other countries that meet the minimum requirement of 50 interventions per centre are being certified to perform TAVI. This study analyses the impact of these requirements on case number and in-hospital outcomes.MethodsAll isolated TAVI procedures and in-hospital outcomes between 2008 and 2016 were identified by International Classification of Diseases (ICD) and the German Operation and Procedure Classification codes.Results73 467 isolated transfemoral and transapical TAVI procedures were performed in Germany between 2008 and 2016. During this period, the number of TAVI procedures per year rose steeply, whereas the overall rates of hospital mortality and complications declined. In 2008, the majority of procedures were performed in hospitals with fewer than 50 cases per year (54.63%). Until 2014, the share of patients treated in low-volume centres constantly decreased to 5.35%. After the revision of recommendations, it further declined to 1.99%. In the 2 years after the introduction of the minimum requirements on case numbers, patients were at decreased risk for in-hospital mortality when treated in a high-volume centre (risk-adjusted OR 0.62, p=0.012). The risk for other in-hospital outcomes (stroke, permanent pacemaker implantation and bleeding events) did not differ after risk adjustment (p=0.346, p=0.142 and p=0.633).ConclusionA minimum volume of 50 procedures per centre and year appears suitable to allow for sufficient routine and thus better in-hospital outcomes, while ensuring nationwide coverage of TAVI procedures.

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