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103
result(s) for
"Geisler, Benjamin"
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Structural transitions, octahedral rotations, and electronic properties of A3Ni2O7 rare-earth nickelates under high pressure
by
Hennig, Richard G
,
Geisler, Benjamin
,
Hirschfeld, P. J
in
Earth rotation
,
External pressure
,
Fermi surfaces
2024
Motivated by the recent observation of superconductivity with Tc ~ 80 K in pressurized La3Ni2O71, we explore the structural and electronic properties of A3Ni2O7 bilayer nickelates (A = La-Lu, Y, Sc) as a function of pressure (0–150 GPa) from first principles including a Coulomb repulsion term. At ~ 20 GPa, we observe an orthorhombic-to-tetragonal transition in La3Ni2O7 at variance with x-ray diffraction data, which points to so-far unresolved complexities at the onset of superconductivity, e.g., charge doping by variations in the oxygen stoichiometry. We compile a structural phase diagram that establishes chemical and external pressure as distinct and counteracting control parameters. We find unexpected correlations between Tc and the in-plane Ni-O-Ni bond angles for La3Ni2O7. Moreover, two structural phases with significant c+ octahedral rotations and in-plane bond disproportionations are uncovered for A = Nd-Lu, Y, Sc that exhibit a pressure-driven electronic reconstruction in the Ni eg manifold. By disentangling the involvement of basal versus apical oxygen states at the Fermi surface, we identify Tb3Ni2O7 as an interesting candidate for superconductivity at ambient pressure. These results suggest a profound tunability of the structural and electronic phases in this novel materials class and are key for a fundamental understanding of the superconductivity mechanism.
Journal Article
Use of Observation Care in US Emergency Departments, 2001 to 2008
by
Baugh, Christopher W.
,
Schuur, Jeremiah D.
,
Geisler, Benjamin P.
in
Adolescent
,
Adult
,
Analysis
2011
Observation care is a core component of emergency care delivery, yet, the prevalence of emergency department (ED) observation units (OUs) and use of observation care after ED visits is unknown. Our objective was to describe the 1) prevalence of OUs in United States (US) hospitals, 2) clinical conditions most frequently evaluated with observation, and 3) patient and hospital characteristics associated with use of observation.
Retrospective analysis of the proportion of hospitals with dedicated OUs and patient disposition after ED visit (discharge, inpatient admission or observation evaluation) using the National Hospital Ambulatory Medical Care Survey (NHAMCS) from 2001 to 2008. NHAMCS is an annual, national probability sample of ED visits to US hospitals conducted by the Center for Disease Control and Prevention. Logistic regression was used to assess hospital-level predictors of OU presence and polytomous logistic regression was used for patient-level predictors of visit disposition, each adjusted for multi-level sampling data. OU analysis was limited to 2007-2008.
In 2007-2008, 34.1% of all EDs had a dedicated OU, of which 56.1% were under ED administrative control (EDOU). Between 2001 and 2008, ED visits resulting in a disposition to observation increased from 642,000 (0.60% of ED visits) to 2,318,000 (1.87%, p<.05). Chest pain was the most common reason for ED visit resulting in observation and the most common observation discharge diagnosis (19.1% and 17.1% of observation evaluations, respectively). In hospital-level adjusted analysis, hospital ownership status (non-profit or government), non-teaching status, and longer ED length of visit (>3.6 h) were predictive of OU presence. After patient-level adjustment, EDOU presence was associated with increased disposition to observation (OR 2.19).
One-third of US hospitals have dedicated OUs and observation care is increasingly used for a range of clinical conditions. Further research is warranted to understand the quality, cost and efficiency of observation care.
Journal Article
Impact of Hurricanes and Associated Extreme Weather Events on Cardiovascular Health: A Scoping Review
by
Setoguchi, Soko
,
Abramson, David
,
Ssebyala, Shakirah N.
in
At risk populations
,
Cardiovascular disease
,
Cardiovascular diseases
2022
The frequency and destructiveness of hurricanes and related extreme weather events (e.g., cyclones, severe storms) have been increasing due to climate change. A growing body of evidence suggests that victims of hurricanes have increased incidence of cardiovascular disease (CVD), likely due to increased stressors around time of the hurricane and in their aftermath.
The objective was to systematically examine the evidence of the association between hurricanes (and related extreme weather events) and adverse CVD outcomes with the goal of understanding the gaps in the literature.
A comprehensive literature search of population-level and cohort studies focused on CVD outcomes (i.e., myocardial infarction, stroke, and heart failure) related to hurricanes, cyclones, and severe storms was performed in the following databases from inception to December 2021: Ovid MEDLINE, Ovid EMBASE, Web of Science, and The Cochrane Library. Studies retrieved were then screened for eligibility against predefined inclusion/exclusion criteria. Studies were then qualitatively synthesized based on the time frame of the CVD outcomes studied and special populations that were studied. Gaps in the literature were identified based on this synthesis.
Of the 1,103 citations identified, 48 met our overall inclusion criteria. We identified articles describing the relationship between CVD and extreme weather, primarily hurricanes, based on data from the United States (42), Taiwan (3), Japan (2), and France (1). Outcomes included CVD and myocardial infarction-related hospitalizations (30 studies) and CVVD-related mortality (7 studies). Most studies used a retrospective study design, including one case-control study, 39 cohort studies, and 4 time-series studies.
Although we identified a number of papers that reported evaluations of extreme weather events and short-term adverse CVD outcomes, there were important gaps in the literature. These gaps included
) a lack of rigorous long-term evaluation of hurricane exposure,
) lack of investigation of hurricane exposure on vulnerable populations regarding issues related to environmental justice,
) absence of research on the exposure of multiple hurricanes on populations, and
) absence of an exploration of mechanisms leading to worsened CVD outcomes. Future research should attempt to fill these gaps, thus providing an important evidence base for future disaster-related policy. https://doi.org/10.1289/EHP11252.
Journal Article
COVID-19 isolation and quarantine orders in Berlin-Reinickendorf (Germany): How many, how long and to whom?
2024
Isolating COVID-19 cases and quarantining their close contacts can prevent COVID-19 transmissions but also inflict harm. We analysed isolation and quarantine orders by the local public health agency in Berlin-Reinickendorf (Germany) and their dependence on the recommendations by the Robert Koch Institute, the national public health institute. Between 3 March 2020 and 18 December 2021 the local public health agency ordered 24 603 isolations (9.2 per 100 inhabitants) and 45 014 quarantines (17 per 100 inhabitants) in a population of 266 123. The mean contacts per case was 1.9. More days of quarantine per 100 inhabitants were ordered for children than for adults: 4.1 for children aged 0-6, 5.2 for children aged 7-17, 0.9 for adults aged 18-64 and 0.3 for senior citizens aged 65-110. The mean duration for isolation orders was 10.2 and for quarantine orders 8.2 days. We calculated a delay of 4 days between contact and quarantine order. 3484 contact persons were in quarantine when they developed an infection. This represents 8% of all individuals in quarantine and 14% of those in isolation. Our study quantifies isolation and quarantine orders, shows that children had been ordered to quarantine more than adults and that there were fewer school days lost to isolation or quarantine as compared to school closures. Our results indicate that the recommendations of the Robert Koch Institute had an influence on isolation and quarantine duration as well as contact identification and that the local public health agency was not able to provide rigorous contact tracing, as the mean number of contacts was lower than the mean number of contacts per person known from literature. Additionally, a considerable portion of the population underwent isolation or quarantine, with a notable number of cases emerging during the quarantine period.
Journal Article
Cost associated with diverting ostomy after rectal cancer surgery: a transnational analysis
by
Geisler, Benjamin P
,
Cao, Khoa N
,
Pietzsch, Jan B
in
Cancer surgery
,
Colorectal cancer
,
Cost control
2023
BackgroundDiverting ileostomy and colostomy after total mesorectal excision reduces the risk of complications related to anastomotic leakages but is associated with a reduction in health-related quality of life and long-term economic consequences that are unknown. Our objective was to estimate the lifetime costs of stoma placement after rectal cancer resection in the U.S., England, and Germany.MethodsInput parameters were derived from quasi-systematic literature searches. Decision-analytic models with survival from colorectal cancer-adjusted life tables and country-specific stoma reversal proportions were created for the three countries to calculate lifetime costs. Main cost items were stoma maintenance costs and reimbursement for reversal procedures. Discounting was applied according to respective national guidelines. Sensitivity analysis was conducted to explore the impact of parameter uncertainty onto the results.ResultsThe cohort starting ages and median survival were 63 and 11.5 years for the U.S., 69 years and 8.5 years for England, and 71 and 6.5 years for Germany. Lifetime discounted stoma-related costs were $26,311, £9512, and €10,021, respectively. All three models were most sensitive to the proportion of ostomy reversal, age at baseline, and discount rate applied.ConclusionConservative model-based projections suggest that stoma care leads to significant long-term costs. Efforts to reduce the number of patients who need to undergo a diverting ostomy could result in meaningful cost savings.
Journal Article
The Effect of Standardized Hospitalist Information Cards on the Patient Experience: a Quasi-Experimental Prospective Cohort Study
by
Lucier, David J
,
Geisler, Benjamin P
,
Abid, Muhammad Hasan
in
Cards
,
Cohort analysis
,
Communication
2022
BackgroundCommunication with clinicians is an important component of a hospitalized patient’s experience.ObjectiveTo test the impact of standardized hospitalist information cards on the patient experience.DesignQuasi-experimental study in a U.S. tertiary-care center.ParticipantsAll-comer medicine inpatients.InterventionsStandardized hospitalist information cards containing name and information on a hospitalist’s role and availability vs. usual care.Main MeasuresPatients’ rating of the overall communication as excellent (“top-box” score); qualitative feedback summarized via inductive coding.Key ResultsFive hundred sixty-six surveys from 418 patients were collected for analysis. In a multivariate regression model, standardized hospitalist information cards significantly improved the odds of a “top-box” score on overall communication (odds ratio: 2.32; 95% confidence intervals: 1.07–5.06). Other statistically significant covariates were patient age (0.98, 0.97–0.99), hospitalist role (physician vs. advanced practice provider, 0.56; 0.38–0.81), and hospitalist-patient gender combination (female-female vs. male-male, 2.14; 1.35–3.40). Eighty-seven percent of patients found the standardized hospitalist information cards useful, the perceived most useful information being how to contact the hospitalist and knowing their schedule.ConclusionsHospitalized patients’ experience of their communication with hospitalists may be improved by using standardized hospitalist information cards. Younger patients cared for by a team with an advanced practice provider, as well as female patients paired with female providers, were more likely to be satisfied with the overall communication. Assessing the impact of information cards should be studied in other settings to confirm generalizability.
Journal Article
Comparing supervised machine learning algorithms for the prediction of partial arterial pressure of oxygen during craniotomy
2025
Background and Objectives
Brain tissue oxygenation is usually inferred from arterial partial pressure of oxygen (paO
2
), which is in turn often inferred from pulse oximetry measurements or other non-invasive proxies. Our aim was to evaluate the feasibility of continuous paO
2
prediction in an intraoperative setting among neurosurgical patients undergoing craniotomies with modern machine learning methods.
Methods
Data from routine clinical care of lung-healthy neurosurgical patients were extracted from databases of the respective clinical systems and normalized. We used recursive feature elimination to identify relevant features for the prediction of paO
2
. Six machine learning regression algorithms (gradient boosting, k-nearest neighbors, random forest, support vector, neural network, linear model with stochastic gradient descent) and a multivariable linear regression were then tuned and fitted to the selected features. A performance matrix consisting of standard deviation of absolute errors (
σ
ae
), mean absolute percentage error (MAPE), adjusted R
2
, root mean squared error (RMSE), mean absolute error (MAE) and Spearman’s
ρ
was finally computed based on the test set, and used to compare and rank each algorithm.
Results
We analyzed
N
= 4,581 patients with
n
= 17,821 observations. Between 5 and 22 features were selected from the analysis of the training dataset comprising 3,436 patients with 13,257 observations. The best algorithm, a regularized linear model with stochastic gradient descent, could predict paO
2
values with σ
ae
= 86.4 mmHg, MAPE = 16 %, adjusted R
2
= 0.77, RMSE = 44 mmHg and Spearman’s ρ = 0.83. Further improvement was possible by calibrating the algorithm with the first measured paO
2
/FiO
2
(p/F) ratio during surgery.
Conclusion
PaO
2
can be predicted by perioperative routine data in neurosurgical patients even before blood gas analysis. The prediction improves further when including the first measured p/F ratio, realizing quasi-continuous paO
2
monitoring.
Journal Article
Economic analysis of endovascular drug-eluting treatments for femoropopliteal artery disease in the UK
by
Garner, Abigail M
,
Geisler, Benjamin P
,
Zayed, Hany
in
Angioplasty
,
Angioplasty, Balloon - economics
,
Angioplasty, Balloon - instrumentation
2016
ObjectivesTo estimate the clinical and economic impact of drug-eluting endovascular treatment strategies for femoropopliteal artery disease compared with current standard of care.DesignSystematic literature search to pool target lesion revascularisations (TLR). Model-based per-patient cost impact and quasi-cost-effectiveness projection over 24 months based on pooled TLRs and current reimbursement.SettingThe UK's National Health Service (NHS).ParticipantsPatients presenting with symptomatic femoropopliteal disease eligible for endovascular treatment.InterventionsCurrent National Institute for Health and Care Excellence (NICE) guideline-recommended treatment with percutaneous transluminal balloon angioplasty (PTA) and bailout bare metal stenting (BMS) versus primary BMS placement, or drug-coated balloon (DCB), or drug-eluting stent (DES) treatment.Primary and secondary outcome measures24-month per-patient cost impact to NHS (primary outcome). Secondary outcomes: pooled 24-month TLR rates; numbers needed to treat (NNTs); cost per TLR avoided and estimated incremental cost-effectiveness ratio (ICER) in £ per quality-adjusted life year (QALY).ResultsN=28 studies were identified, reporting on 5167 femoropopliteal lesions. Over 24 months, DCB, DES and BMS reduced TLRs of de novo lesions from 36.2% to 17.6%, 19.4% and 26.9%, respectively, at an increased cost of £43, £44 and £112. NNTs to avoid 1 TLR in 24 months were 5.4, 6.0 and 10.8, resulting in cost per TLR avoided of £231, £264 and £1204. DCB was estimated to add 0.011 QALYs, DES 0.010 QALYs and BMS 0.005 QALYs, resulting in estimated ICERs of £3983, £4534 and £20 719 per QALY gained. A subset analysis revealed more favourable clinical and economic outcomes for a 3.5 µg/mm2 DCB with urea excipient, compared with the rest of DCBs. A modest reduction of 10% in DCB and DES prices made drug-eluting treatments dominant.ConclusionsWidespread adoption of drug-eluting endovascular therapies for femoropopliteal disease would add meaningful clinical benefit at reasonable additional costs to the NHS. Based on currently available data, DCBs offer the highest clinical and economic value.
Journal Article
Principles of Economic Evaluation in a Pandemic Setting: An Expert Panel Discussion on Value Assessment During the Coronavirus Disease 2019 Pandemic
by
Garrison, Louis P.
,
Asukai, Yumi
,
Geisler, Benjamin P.
in
Coronaviruses
,
Cost analysis
,
Cost-Benefit Analysis
2021
As the coronavirus disease 2019 (COVID-19) pandemic continues to generate significant morbidity and mortality as well as economic and societal impacts, the landscape of potential treatments has slowly begun to broaden. In the case of a novel disease with widespread consequences, society is more likely to place significant value on interventions that reduce the outsized economic burden of COVID-19. Treatments for severe disease will have a different value profile to that of large-scale vaccines because of their application in targeted and potentially small subsets of those with symptomatic disease vs broad deployment as a preventative measure. Where vaccines reduce transmissibility of COVID-19, use of therapeutics will target symptoms, up to and including death for infected individuals. This paper describes discussions from a virtual expert panel that met to attempt a consensus on how existing principles of economic evaluation should be applied to therapeutics that emerge in a pandemic setting, with specific focus on severe hospitalised cases of COVID-19. The panel concluded that the core principles of economic evaluation do not need to be drastically overhauled to meet the challenges of a pandemic, but that there are several additional elements of value such as equity, disease severity, insurance value, and scientific and family spillover effects that should be considered when presenting results to decision makers. The panel also highlighted the persistent challenges on how society should value novel therapies, such as the appropriate cost-effectiveness threshold to apply, which are particularly salient during a pandemic.
Journal Article
Clinical and Economic Benefits of Upper Airway Stimulation for Obstructive Sleep Apnea in a European Setting
by
Wasem, Jürgen
,
Pietzsch, Jan Benjamin
,
Steffen, Armin
in
Analysis
,
Care and treatment
,
Clinical Investigations
2019
Background: Upper airway stimulation (UAS) is a treatment approach for patients with moderate-to-severe obstructive sleep apnea who cannot adhere to continuous positive airway pressure therapy. Objective: The objective was to evaluate added patient benefit and cost-effectiveness of UAS in the German health care system. Methods: We used a decision-analytic Markov model to project major adverse cardiovascular or cerebrovascular events (myocardial infarction [MI] or stroke), motor vehicle collision (MVC), mortality, quality-adjusted life years (QALYs), and costs. The assumed reduction in the apnea-hypopnea index with UAS compared to no treatment is based on German real-world data. Other input data were derived from the literature, public statistics, and multivariate regression. Cost-effectiveness was evaluated in Euros per QALY gained, both discounted at 3%. Results: UAS was projected to reduce event risks (10-year relative risk for stroke, MI, cardiovascular death, and MVC: 0.76, 0.64, 0.65, and 0.34, respectively), and to increase survival by 1.27 years. While the UAS strategy incurred an additional 1.02 QALYs within the patient lifetime, there were also additional costs of EUR 45,196, resulting in an incremental cost-effectiveness ratio of EUR 44,446 per QALY gained. Conclusions: In the present model-based analysis, UAS therapy provides meaningful benefit to patient-relevant endpoints and is a cost-effective therapy in the German setting.
Journal Article