Consumers often incur costs when switching from one product to another. Recently, there has been renewed debate within the literature about whether these switching costs lead to higher prices. We ...build a theoretical model of dynamic competition and solve it analytically for a wide range of switching costs. We provide a simple condition which determines whether switching costs raise or lower long-run prices. We also show that even if switching costs reduce prices in the long run, they may still increase prices in the short run. Finally, switching costs redistribute surplus across time, and as such are shown to sometimes increase consumer welfare.
A puzzling feature of many retail markets is the coexistence of large multiproduct firms and smaller firms with narrow product ranges. This paper provides a possible explanation for this puzzle, by ...studying how consumer search frictions influence the structure of retail markets. In our model, single-product firms that supply different products can merge to form a multiproduct firm. Consumers wish to buy multiple products and, due to search frictions, value the one-stop shopping convenience associated with a multiproduct firm. We find that, when search frictions are relatively large, all firms are multiproduct in equilibrium. However, when search frictions are smaller, the equilibrium market structure is asymmetric, with different retail formats coexisting. This allows firms to better segment the market and, as such, typically leads to the weakest price competition. When search frictions are low, this asymmetric market structure is also the worst for consumers. Moreover, due to the endogeneity of market structure, a reduction in the search friction can increase market prices and harm consumers.
The online appendix is available at
https://doi.org/10.1287/mnsc.2018.3058
.
This paper was accepted by Eric Anderson, marketing.
Complications from major surgery are undesirable, common, and potentially avoidable. The long-term consequences of short-term surgical complications have recently been recognized to have a profound ...influence on longevity and quality of life in survivors. In the past 30 years, there have been a number of studies conducted attempting to reduce surgical mortality and morbidity by deliberately and preemptively manipulating perioperative hemodynamics. Early studies had a high control-group mortality rate and were criticized for this as being unrepresentative of current practice and raised opposition to its implementation as routine care. We performed this review to update this body of literature and to examine the effect of changes in current practice and quality of care to see whether the conclusions from previous quantitative analyses of this field remain valid.
Randomized clinical trials evaluating the use of preemptive hemodynamic intervention to improve surgical outcome were identified using multiple methods. Electronic databases (MEDLINE, EMBASE, and the Cochrane Controlled Clinical Trials register) were screened for potential trials, reference lists of identified trials were examined, and additional sources were sought from experts and industry representatives. Identified studies that fulfilled the entry criteria were examined in full and subjected to quantifiable analysis, subgroup analysis, and sensitivity analysis where possible.
There were 29 studies identified, 23 of which reported surgical complications. In total, the 29 trials involved 4805 patients with an overall mortality of 7.6%. The use of preemptive hemodynamic intervention significantly reduced mortality (pooled odds ratio 95% confidence interval of 0.48 0.33-0.78; P = 0.0002) and surgical complications (odds ratio 0.43 0.34-0.53; P < 0.0001). Subgroup analysis showed significant reductions in mortality for studies using a pulmonary artery catheter, supranormal resuscitation targets, studies using cardiac index or oxygen delivery as goals, and the use of fluids and inotropes as opposed to fluids alone. By contrast, there was a significant reduction in morbidity for each of the 4 subgroups analyzed.
The use of a preemptive strategy of hemodynamic monitoring and coupled therapy reduces surgical mortality and morbidity.
Summary Background Mortality from severe sepsis and septic shock differs across continents, countries, and regions. We aimed to use data from the Surviving Sepsis Campaign (SSC) to compare models of ...care and outcomes for patients with severe sepsis and septic shock in the USA and Europe. Methods The SSC was introduced into more than 200 sites in Europe and the USA. All patients identified with severe sepsis and septic shock in emergency departments or hospital wards and admitted to intensive care units (ICUs), and those with sepsis in ICUs were entered into the SSC database. Patients entered into the database from its launch in January, 2005, through January, 2010, in units with at least 20 patients and 3 months of enrolment of patients were included in this analysis. Patients included in the cohort were limited to those entered in the first 4 years at every site. We used random-effects logistic regression to estimate the hospital mortality odds ratio (OR) for Europe relative to the USA. We used random-effects linear regression to find the relation between lengths of stay in hospital and ICU and geographic region. Findings 25 375 patients were included in the cohort. The USA included 107 sites with 18 766 (74%) patients, and Europe included 79 hospital sites with 6609 (26%) patients. In the USA, 12 218 (65·1%) were admitted to the ICU from the emergency department whereas in Europe, 3405 (51·5%) were admitted from the wards. The median stay on the hospital wards before ICU admission was longer in Europe than in the USA (1·0 vs 0·1 days, difference 0·9, 95% CI 0·8–0·9). Raw hospital mortality was higher in Europe than in the USA (41·1% vs 28·3%, difference 12·8, 95% CI 11·5–14·7). The median length of stay in ICU (7·8 vs 4·2 days, 3·6, 3·3–3·7) and hospital (22·8 vs 10·5 days, 12·3, 11·9–12·8) was longer in Europe than in the USA. Adjusted mortality in Europe was not significantly higher than that in the USA (32·3% vs 31·3%, 1·0, −1·7 to 3·7, p=0·468). Complete compliance with all applicable elements of the sepsis resuscitation bundle was higher in the USA than in Europe (21·6% vs 18·4%, 3·2, 2·2–4·4). Interpretation The significant difference in unadjusted mortality and the fact that this difference disappears with severity adjustment raise important questions about the effect of the approach to critical care in Europe compared with that in the USA. The effect of ICU bed availability on outcomes in patients with severe sepsis and septic shock requires further investigation. Funding Eli Lilly Co, Baxter Lifesciences, Philips Medical Systems, the Society of Critical Care Medicine, and the European Society of Intensive Care Medicine.
Objective
Circulatory shock is a life-threatening syndrome resulting in multiorgan failure and a high mortality rate. The aim of this consensus is to provide support to the bedside clinician ...regarding the diagnosis, management and monitoring of shock.
Methods
The European Society of Intensive Care Medicine invited 12 experts to form a Task Force to update a previous consensus (Antonelli et al.: Intensive Care Med 33:575–590, 2007). The same five questions addressed in the earlier consensus were used as the outline for the literature search and review, with the aim of the Task Force to produce statements based on the available literature and evidence. These questions were: (1) What are the epidemiologic and pathophysiologic features of shock in the intensive care unit? (2) Should we monitor preload and fluid responsiveness in shock? (3) How and when should we monitor stroke volume or cardiac output in shock? (4) What markers of the regional and microcirculation can be monitored, and how can cellular function be assessed in shock? (5) What is the evidence for using hemodynamic monitoring to direct therapy in shock? Four types of statements were used: definition, recommendation, best practice and statement of fact.
Results
Forty-four statements were made. The main new statements include: (1) statements on individualizing blood pressure targets; (2) statements on the assessment and prediction of fluid responsiveness; (3) statements on the use of echocardiography and hemodynamic monitoring.
Conclusions
This consensus provides 44 statements that can be used at the bedside to diagnose, treat and monitor patients with shock.
Introduction
Despite evidence demonstrating the value of performance initiatives, marked differences remain between hospitals in the delivery of care for patients with sepsis. The aims of this study ...were to improve our understanding of how compliance with the 3-h and 6-h Surviving Sepsis Campaign (SSC) bundles are used in different geographic areas, and how this relates to outcome.
Methods
This was a global, prospective, observational, quality improvement study of compliance with the SSC bundles in patients with either severe sepsis or septic shock.
Results
A total of 1794 patients from 62 countries were enrolled in the study with either severe sepsis or septic shock. Overall compliance with all the 3-h bundle metrics was 19 %. This was associated with lower hospital mortality than non-compliance (20 vs. 31 %,
p
< 0.001). Overall compliance with all the 6-h bundle metrics was 36 %. This was associated with lower hospital mortality than non-compliance (22 vs. 32 %,
p
< 0.001). After adjusting the crude mortality differences for ICU admission, sepsis status (severe sepsis or septic shock), location of diagnosis, APACHE II score and country, compliance remained independently associated with improvements in hospital mortality for both the 3-h bundle (OR = 0.64 (95 % CI 0.47−0.87),
p
= 0.004)) and 6-h bundle (OR = 0.71 (95 % CI 0.56−0.90),
p
= 0.005)).
Discussion
Compliance with all of the evidence-based bundle metrics was not high. Patients whose care included compliance with all of these metrics had a 40 % reduction in the odds of dying in hospital with the 3-h bundle and 36 % for the 6-h bundle.
Patients with limited cardiac reserve are less likely to survive and develop more complications following major surgery. By augmenting oxygen delivery index (DO2I) with a combination of intravenous ...fluids and inotropes (goal directed therapy (GDT)), postoperative mortality and morbidity of high-risk patients may be reduced. However, although most studies suggest that GDT may improve outcome in high-risk surgical patients, it is still not widely practiced. We set out to test the hypothesis that GDT results in greatest benefit in terms of mortality and morbidity in patients with the highest risk of mortality and have undertaken a systematic review of the current literature to see if this is correct. We performed a systematic search of Medline, Embase and CENTRAL databases for randomized controlled trials (RCTs) and reviews of GDT in surgical patients. To minimize heterogeneity we excluded studies involving cardiac, trauma, and paediatric surgery. Extremely high risk, high risk and intermediate risks of mortality were defined as >20%, 5 to 20% and <5% mortality rates in the control arms of the trials, respectively. Meta analyses were performed and Forest plots drawn using RevMan software. Data are presented as odd ratios (OR; 95% confidence intervals (CI), and P-values). A total of 32 RCTs including 2,808 patients were reviewed. All studies reported mortality. Five studies (including 300 patients) were excluded from assessment of complication rates as the number of patients with complications was not reported. The mortality benefit of GDT was confined to the extremely high-risk group (OR = 0.20, 95% CI 0.09 to 0.41; P < 0.0001). Complication rates were reduced in all subgroups (OR = 0.45, 95% CI 0.34 to 0.60; P < 0.00001). The morbidity benefit was greatest amongst patients in the extremely high-risk subgroup (OR = 0.27, 95% CI 0.15 to 0.51; P < 0.0001), followed by the intermediate risk subgroup (OR = 0.43, 95% CI 0.27 to 0.67; P = 0.0002), and the high-risk subgroup (OR 0.56, 95% CI 0.36 to 0.89; P = 0.01). Despite heterogeneity in trial quality and design, we found GDT to be beneficial in all high-risk patients undergoing major surgery. The mortality benefit of GDT was confined to the subgroup of patients at extremely high risk of death. The reduction of complication rates was seen across all subgroups of GDT patients.
The fluid challenge is considered the gold standard for diagnosis of fluid responsiveness. The objective of this study was to describe the fluid challenge techniques reported in fluid responsiveness ...studies and to assess the difference in the proportion of 'responders,' (PR) depending on the type of fluid, volume, duration of infusion and timing of assessment.
Searches of MEDLINE and Embase were performed for studies using the fluid challenge as a test of cardiac preload with a description of the technique, a reported definition of fluid responsiveness and PR. The primary outcome was the mean PR, depending on volume of fluid, type of fluids, rate of infusion and time of assessment.
A total of 85 studies (3601 patients) were included in the analysis. The PR were 54.4% (95% CI 46.9-62.7) where <500 ml was administered, 57.2% (95% CI 52.9-61.0) where 500 ml was administered and 60.5% (95% CI 35.9-79.2) where >500 ml was administered (p = 0.71). The PR was not affected by type of fluid. The PR was similar among patients administered a fluid challenge for <15 minutes (59.2%, 95% CI 54.2-64.1) and for 15-30 minutes (57.7%, 95% CI 52.4-62.4, p = 1). Where the infusion time was ≥30 minutes, there was a lower PR of 49.9% (95% CI 45.6-54, p = 0.04). Response was assessed at the end of fluid challenge, between 1 and 10 minutes, and >10 minutes after the fluid challenge. The proportions of responders were 53.9%, 57.7% and 52.3%, respectively (p = 0.47).
The PR decreases with a long infusion time. A standard technique for fluid challenge is desirable.
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