To pool or not to pool in hospitals: a theoretical and practical comparison for a radiotherapy outpatient department

This paper examines whether urgent and regular patients waiting for a consultation at a radiotherapy outpatient department should be pooled or not. Both queuing theory and discrete event simulation were applied to a realistic case study. The theoretical approach shows that pooling is not always beneficial with regard to the waiting times of urgent patients. Furthermore, the practical approach indicates that the separation of queues may require less capacity to meet the waiting time performance target for urgent as well as regular patients. The results seem to be of general interest for hospital

How to juggle priorities? An interactive tool to provide quantitative support for strategic patient-mix decisions: an ophthalmology case

An interactive tool was developed for the ophthalmology department of the Academic Medical Center to quantitatively support management with strategic patient-mix decisions. The tool enables management to alter the number of patients in various patient groups and to see the consequences in terms of key performance indicators. In our case study, we focused on the bottleneck: the operating room. First, we performed a literature review to identify all factors that influence an operating room's utilization rate. Next, we decided which factors were relevant to our study. For these relevant factors, two quantitative methods were applied to quantify the impact of an individual factor: regression analysis and computer simulation. Finally, the average duration of an operation, the number of cancellations due to overrun of previous surgeries, and the waiting time target for elective patients all turned out to have significant impact. Accordingly, for the case study, the interactive tool was shown to offer management quantitative decision support to act proactively to expected alterations in patient-mix. Hence, management can anticipate the future situation, and either alter the expected patient-mix or expand capacity to ensure that the key performance indicators will be met in the future

Molecular mechanisms involved in pulmonary arterial hypertension development

Pulmonary arterial hypertension (PAH) is an elevation in pulmonary arterial pressure, characterized by symptoms of dyspnea, chest pain, decrease in exercise tolerance-fatigue, syncope and, if untreated, PAH leads to right heart failure. In PAH, there is an imbalance between mediators of vasodilation and vasoconstriction (e.g. nitric oxide and prostacycline – potent vasodilators, platelet inhibitor and antimitogens are decreased in PAH, while thromboxane, vasoconstrictor and platelet activator is increased in PAH, resulting in smooth muscle hypertrophy of small vessels, adventitial and intimal proliferation, and plexiform vascular lesions with vascular thrombosis). Standard diagnostic procedures for PAH include physical examination, pulmonary function testing, radiographic imaging, transthoracic echocardiography, right heart catheterization. Current drugs include synthet c prostanoids (iloprost, epoprostenil, beraprost, treprostinil) – vasodilators and antiplatelet agents. Phosphodiesterase-5 inhibitors decrease the breakdown of cGMP, increasing its intracellular levels, leukotriene receptor antagonist, – zafirlukast, decreases pulmonary arterial and venous pressure. Endothelin receptor blockers, bosentan, decrease pulmonary vascular resistance and improve results of functional tests. Other treatments are: anticoagulants, calcium-channel blockers, positive airway pressure therapy for obstructive sleep apnea, or oxygen for hypoxemia, and surgery. In conclusion, although there are some promising drugs in therapy of PAH, there is a need to develop new ones, together with surgical approaches, in order to increase the survival of patients with PAH. Gene and cell therapy could be expected as future perspectives

Can Statisticians Beat Surgeons at the Planning of Operations, Discussion paper 2010/06

Abstract The planning of operations in the Academic Medical Center is primarily based on the assessments of the length of the operation by the surgeons. We investigate whether duration models employing the information available at the moment the planning is made, offer a better alternative. We conclude that substantial cost reductions can be achieved by employing statistical techniques. This does not imply that the surgeons' predictions do not contain valuable information. This information is a key explanatory variable in our statistical models. What our conclusion does entail is that a correction of the predictions of surgeons is possible because they are often underestimating the actual length of operations. 1 All ML-routines used in this paper are either performed by using standard routines from Stata or are carried out using R (free software, for information see http://www.r-project.org/)

UvA-DARE (Digital Academic Repository) Can statisticians beat surgeons at the planning of operations? Can statisticians beat surgeons at the planning of operations? Can statisticians beat surgeons at the planning of operations?

Abstract The planning of operations in the Academic Medical Center is primarily based on the assessments of the length of the operation by the surgeons. We investigate whether duration models employing the information available at the moment the planning is made, offer a better alternative. We conclude that substantial cost reductions can be achieved by employing statistical techniques. This does not imply that the surgeons' predictions do not contain valuable information. This information is a key explanatory variable in our statistical models. What our conclusion does entail is that a correction of the predictions of surgeons is possible because they are often underestimating the actual length of operations. 1 All ML-routines used in this paper are either performed by using standard routines from Stata or are carried out using R (free software, for information see http://www.r-project.org/)

UvA-DARE (Digital Academic Repository) Can statisticians beat surgeons at the planning of operations? Can statisticians beat surgeons at the planning of operations?

Abstract The planning of operations in the Academic Medical Center is primarily based on the assessments of the length of the operation by the surgeons. We investigate whether duration models employing the information available at the moment the planning is made, offer a better alternative. Our empirical results indicate that statistical methods often do better than surgeons. This does not imply that the surgeons' predictions do not contain valuable information. This information is a key explanatory variable in our statistical models. What our conclusion does entail is that a correction of the predictions of surgeons is possible because they are often under-or overestimating the actual length of operations. All ML-routines used in this paper are either performed by using standard routines from Stata or are carried out using R (free software, for information see http://www.r-project.org/)

Reducing MRI access times by tackling the appointment-scheduling strategy

BACKGROUND: High access times for MRI facilities have a negative impact on quality of care and patient service. Since these resources are both scarce and expensive, better utilising the capacity is the most economical way of reducing these access times. As a rule, patient appointments are not scheduled efficiently. Consequently, the most promising way of reducing access times is to optimise the scheduling strategy. The aim of this study was to reduce MRI access times by optimising the scheduling strategy and by implementing this strategy in practice in a university hospital in the Netherlands. ASSESSMENT OF PROBLEMS: The scheduling process was analysed to define the improvement potentials and to simulate the process. Computer simulation was used to copy the process and experiment with scheduling strategies in theory. Promising scenarios were defined and run in the simulation model. Based on the simulation results, a new scheduling strategy was designed and implemented. RESULTS OF ASSESSMENT: The simulation experiments showed that block reduction leads to a maximum decrease in access time of 93%. STRATEGIES FOR CHANGE: Implementing a scheduling strategy with a practically applicable minimum number of blocks resulted in an actual decrease from 36, 22, 28, 9 and 9 to 7, 2, 10, 3 and 1 calendar days, respectively, depending on the patient group. LESSONS AND MESSAGES: This study proved that modelling the scheduling process can contribute to optimising the scheduling strategy, which can lead to a reduction in access times for imaging facilities such as MRI scanner

IGSF1 Deficiency Results in Human and Murine Somatotrope Neurosecretory Hyperfunction.

CONTEXT: The X-linked immunoglobulin superfamily, member 1 (IGSF1), gene is highly expressed in the hypothalamus and in pituitary cells of the POU1F1 lineage. Human loss-of-function mutations in IGSF1 cause central hypothyroidism, hypoprolactinemia, and macroorchidism. Additionally, most affected adults exhibit higher than average IGF-1 levels and anecdotal reports describe acromegaloid features in older subjects. However, somatotrope function has not yet been formally evaluated in this condition. OBJECTIVE: We aimed to evaluate the role of IGSF1 in human and murine somatotrope function. PATIENTS, DESIGN, AND SETTING: We evaluated 21 adult males harboring hemizygous IGSF1 loss-of-function mutations for features of GH excess, in an academic clinical setting. MAIN OUTCOME MEASURES: We compared biochemical and tissue markers of GH excess in patients and controls, including 24-hour GH profile studies in 7 patients. Parallel studies were undertaken in male Igsf1-deficient mice and wild-type littermates. RESULTS: IGSF1-deficient adult male patients demonstrated acromegaloid facial features with increased head circumference as well as increased finger soft-tissue thickness. Median serum IGF-1 concentrations were elevated, and 24-hour GH profile studies confirmed 2- to 3-fold increased median basal, pulsatile, and total GH secretion. Male Igsf1-deficient mice also demonstrated features of GH excess with increased lean mass, organ size, and skeletal dimensions and elevated mean circulating IGF-1 and pituitary GH levels. CONCLUSIONS: We demonstrate somatotrope neurosecretory hyperfunction in IGSF1-deficient humans and mice. These observations define a hitherto uncharacterized role for IGSF1 in somatotropes and indicate that patients with IGSF1 mutations should be evaluated for long-term consequences of increased GH exposure.: We acknowledge support from the Wellcome Trust to NS (100585/Z/12/A), GRW and JHDB (Strategic Award 101123/Z/13/A; Joint Investigator Awards 110140/Z/15/Z and 110141/Z/15/Z) and The National Institute for Health Research Biomedical Research Centre Cambridge (MG, NS). The Disease Model Core is supported by the UK MRC Metabolic Diseases Unit [MC_UU_00014/5] and the Wellcome Trust Major Award [208363/Z/17/Z]). PLT was funded by the UK MRC (U117562207). The Core biochemical Assay Laboratory is supported by MRC Metabolic Diseases Unit [MC_UU_00014/5]. DJB was supported by grants from the Canadian Institutes of Health Research (MOP-133557) and the Natural Sciences and Engineering Research Council of Canada (2015-05178)