Impact of Mesh Use on Morbidity Following Ventral Hernia Repair With a Simultaneous Bowel Resection

Objective: To evaluate the impact of mesh use on outcomes following ventral hernia repairs and simultaneous bowel resection. Design: Retrospective review. Setting: Teaching academic hospital. Patients: We studied 177 patients who underwent a ventral hernia repair with a bowel resection between May 1, 1992, and May 30, 2007. A prosthesis was used in 51 repairs (mesh group), while 126 repairs were primary (mesh-free group). Main Outcome Measures: Demographic characteristics, comorbidities, mesh type, bowel resection type (colon vs small bowel), defect size, drain use, and length of hospital stay were compared between groups with Fisher exact test and multivariate analysis. Results: There were no statistically significant differences between patient characteristics and relevant comorbidities. The incidence of postoperative infection (superficial or deep) was 22% in the mesh group vs 5% in the mesh-free group (P = .001). Other complications (fistula, seroma, hematoma, bowel obstruction) occurred in 24% of patients in the mesh group vs 8% of patients in the mesh-free group (P = .009). Focusing on the patients who developed an infection, prosthetic mesh use was the only significant risk factor on multivariate regression analysis, irrespective of drain use, defect size, and type of bowel resection. Conclusions: We recommend caution in using mesh when performing a ventral hernia repair with a simultaneous bowel resection because of significantly increased postoperative infectious complications. Drain use, defect size, and bowel resection type did not influence outcomes

A systems framework for remedying dysfunction in U.S. democracy

Democracy often fails to meet its ideals, and these failures may be made worse by electoral institutions. Unwanted outcomes include polarized institutions, unresponsive representatives, and the ability of a faction of voters to gain power at the expense of the majority. Various reforms have been proposed to address these problems, but their effectiveness is difficult to predict against a backdrop of complex interactions. Here we outline a path for systems-level modeling to help understand and optimize repairs to U.S. democracy. Following the tradition of engineering and biology, models of systems include mechanisms with dynamical properties that include nonlinearities and amplification (voting rules), positive feedback mechanisms (single-party control, gerrymandering), negative feedback (checks and balances), integration over time (lifetime judicial appointments), and low dimensionality (polarization). To illustrate a systems-level approach we analyze three emergent phenomena: low dimensionality, elite polarization, and anti-majoritarianism in legislatures. In each case, long-standing rules now contribute to undesirable outcomes as a consequence of changes in the political environment. Theoretical understanding at a general level will also help evaluate whether a proposed reform's benefits will materialize and be lasting, especially as conditions change again. In this way, rigorous modeling may not only shape new lines of research, but aid in the design of effective and lasting reform

Audit-identified avoidable factors in maternal and perinatal deaths in low resource settings: a systematic review

Background: Audits provide a rational framework for quality improvement by systematically assessing clinical practices against accepted standards with the aim to develop recommendations and interventions that target modifiable deficiencies in care. Most childbirth-associated mortality audits in developing countries are focused on a single facility and, up to now, the avoidable factors in maternal and perinatal deaths cataloged in these reports have not been pooled and analyzed. We sought to identity the most frequent avoidable factors in childbirth-related deaths globally through a systematic review of all published mortality audits in low and lower-middle income countries. Methods: We performed a systematic review of published literature from 1965 to November 2011 in Pubmed, Embase, CINAHL, POPLINE, LILACS and African Index Medicus. Inclusion criteria were audits from low and lower-middle income countries that identified at least one avoidable factor in maternal or perinatal mortality. Each study included in the analysis was assigned a quality score using a previously published instrument. A meta-analysis was performed for each avoidable factor taking into account the sample sizes and quality score from each individual audit. The study was conducted and reported according to PRISMA guidelines for systematic reviews. Results: Thirty-nine studies comprising 44 datasets and a total of 6,205 audited deaths met inclusion criteria. The analysis yielded 42 different avoidable factors, which fell into four categories: health worker-oriented factors, patient-oriented factors, transport/referral factors, and administrative/supply factors. The top three factors by attributable deaths were substandard care by a health worker, patient delay, and deficiencies in blood transfusion capacity (accounting for 688, 665, and 634 deaths attributable, respectively). Health worker-oriented factors accounted for two-thirds of the avoidable factors identified. Conclusions: Audits provide insight into where systematic deficiencies in clinical care occur and can therefore provide crucial direction for the targeting of interventions to mitigate or eliminate health system failures. Given that the main causes of maternal and perinatal deaths are generally consistent across low resource settings, the specific avoidable factors identified in this review can help to inform the rational design of health systems with the aim of achieving continued progress towards Millennium Development Goals Four and Five. Electronic supplementary material The online version of this article (doi:10.1186/1471-2393-14-280) contains supplementary material, which is available to authorized users

Comparison of techniques for handling missing covariate data within prognostic modelling studies: a simulation study

Background: There is no consensus on the most appropriate approach to handle missing covariate data within prognostic modelling studies. Therefore a simulation study was performed to assess the effects of different missing data techniques on the performance of a prognostic model. Methods: Datasets were generated to resemble the skewed distributions seen in a motivating breast cancer example. Multivariate missing data were imposed on four covariates using four different mechanisms; missing completely at random (MCAR), missing at random (MAR), missing not at random (MNAR) and a combination of all three mechanisms. Five amounts of incomplete cases from 5% to 75% were considered. Complete case analysis (CC), single imputation (SI) and five multiple imputation (MI) techniques available within the R statistical software were investigated: a) data augmentation (DA) approach assuming a multivariate normal distribution, b) DA assuming a general location model, c) regression switching imputation, d) regression switching with predictive mean matching (MICE-PMM) and e) flexible additive imputation models. A Cox proportional hazards model was fitted and appropriate estimates for the regression coefficients and model performance measures were obtained. Results: Performing a CC analysis produced unbiased regression estimates, but inflated standard errors, which affected the significance of the covariates in the model with 25% or more missingness. Using SI, underestimated the variability; resulting in poor coverage even with 10% missingness. Of the MI approaches, applying MICE-PMM produced, in general, the least biased estimates and better coverage for the incomplete covariates and better model performance for all mechanisms. However, this MI approach still produced biased regression coefficient estimates for the incomplete skewed continuous covariates when 50% or more cases had missing data imposed with a MCAR, MAR or combined mechanism. When the missingness depended on the incomplete covariates, i.e. MNAR, estimates were biased with more than 10% incomplete cases for all MI approaches. Conclusion: The results from this simulation study suggest that performing MICE-PMM may be the preferred MI approach provided that less than 50% of the cases have missing data and the missing data are not MNAR

Euglycemic Hyperinsulinemia Alters the Response to Orthostatic Stress in Older Adults With Type 2 Diabetes

OBJECTIVE—Insulin has opposing influences on blood pressure by simultaneously increasing adrenergic activity and vasodilatating peripheral blood vessels. In this study, we sought to determine whether hyperinsulinemia affects tilt table responses in older adults with type 2 diabetes not complicated by orthostatic hypotension

Geographic Variation Within the Military Health System

Background: This study seeks to quantify variation in healthcare utilization and per capita costs using system-defined geographic regions based on enrollee residence within the Military Health System (MHS). Methods: Data for fiscal years 2007 – 2010 were obtained from the Military Health System under a data sharing agreement with the Defense Health Agency (DHA). DHA manages all aspects of the Department of Defense Military Health System, including TRICARE. Adjusted rates were calculated for per capita costs and for two procedures with high interest to the MHS- back surgery and Cesarean sections for TRICARE Prime and Plus enrollees. Coefficients of variation (CoV) and interquartile ranges (IQR) were calculated and analyzed using residence catchment area as the geographic unit. Catchment areas anchored by a Military Treatment Facility (MTF) were compared to catchment areas not anchored by a MTF. Results: Variation, as measured by CoV, was 0.37 for back surgery and 0.13 for C-sections in FY 2010- comparable to rates documented in other healthcare systems. The 2010 CoV (and average cost) for per capita costs was 0.26 ($3,479.51). Procedure rates were generally lower and CoVs higher in regions anchored by a MTF compared with regions not anchored by a MTF, based on both system-wide comparisons and comparisons of neighboring areas. Conclusions: In spite of its centrally managed system and relatively healthy beneficiaries with very robust health benefits, the MHS is not immune to unexplained variation in utilization and cost of healthcare

Is elevated creatinine level a contraindication to endovascular aneurysm repair?

AbstractPurposeIt is widely believed that chronic renal insufficiency (CRI) greatly increases the risk associated with endovascular abdominal aortic aneurysm repair (EVAR) and is a relative contraindication to the procedure and to the use of intra-arterial contrast agents (IACA). We reviewed a 5-year EVAR experience to determine whether the procedure and use of IACA have an important deleterious effect on renal function in patients with and without pre-existing CRI.MethodsEndovascular aneurysm repair (EVAR) was performed in 200 patients with a variety of endografts, with intra-arterial contrast agents. The patients were retrospectively assigned to three groups on the basis of preoperative serum creatinine concentration (Cr): group 1 (n = 108), Cr less than 1.5 mg/dL (normal range); group 2 (n = 65), Cr 1.5 to 2.0 mg/dL; group 3 (n = 27), Cr 2.1 to 3.5 mg/dL. No patients had undergone hemodialysis. In groups 2 and 3, patients received hydration perioperatively, and received mannitol intraoperatively; no nephrotoxic drugs were administered during the procedure, other than nonionic contrast agent (Omnipaque 350).ResultsThe incidence of postoperative complications between the three study groups was not statistically different. In group 1 a transient increase in serum Cr (>30% over baseline and >1.4 mg/dL) was noted in three patients (2.7%), two of whom (1.9%) required temporary hemodialysis and one (0.9%) who died of renal failure. In group 2 a transient increase in serum Cr was noted in two patients (3.1%); both patients (3.1%) required temporary hemodialysis, and one patient (1.5%) died of renal failure. In group 3 a transient increase in serum Cr was noted in two patients (7.4%); one patient (3.7%) required temporary hemodialysis, and one patient (3.7%) died of renal failure. Perioperative hypotension significantly increased the risk for elevated serum Cr and death (P < .05), and larger contrast volume was associated with an increase in serum Cr (P < .05) during the postoperative period.ConclusionsEVAR with intra-arterial contrast agents can be accomplished in patients with chronic renal insufficiency who do not require dialysis, with limited and acceptable morbidity and mortality, similar to that observed with open aneurysm repair. Contrary to other reports in which perioperative precautions were not used, our study shows that with EVAR the risk for worsening renal failure, dialysis, and death is only slightly, and not significantly, greater in patients with preoperative chronic renal insufficiency compared with patients with normal renal function. Perioperative hypotension and increased contrast volume are significant risk factors for postoperative increase in serum Cr and death. With appropriate precautions such as averting perioperative hypotension and limiting the volume of nonionic contrast agents, elevated Cr need not be a contraindication to EVAR with intra-arterial contrast agents

The increase of the functional entropy of the human brain with age

We use entropy to characterize intrinsic ageing properties of the human brain. Analysis of fMRI data from a large dataset of individuals, using resting state BOLD signals, demonstrated that a functional entropy associated with brain activity increases with age. During an average lifespan, the entropy, which was calculated from a population of individuals, increased by approximately 0.1 bits, due to correlations in BOLD activity becoming more widely distributed. We attribute this to the number of excitatory neurons and the excitatory conductance decreasing with age. Incorporating these properties into a computational model leads to quantitatively similar results to the fMRI data. Our dataset involved males and females and we found significant differences between them. The entropy of males at birth was lower than that of females. However, the entropies of the two sexes increase at different rates, and intersect at approximately 50 years; after this age, males have a larger entropy

Mixed-Methods Evaluation of Real-Time Safety Reporting by Hospitalized Patients and Their Care Partners:The MySafeCare Application

OBJECTIVE: To evaluate the amount and content of data patients and carepartners reported using a real-time electronic safety tool compared to other reporting mechanisms, and understand their perspectives on safety concerns and reporting in the hospital. METHODS: Mixed-methods study including 20 month pre- and post-implementation trial evaluating MySafeCare, a web-based application which allows hospitalized patients/carepartners to report safety concerns in real-time. Comparison of MySafeCare submission rates for three hospital units (oncology acute care; vascular intermediate care; medical intensive care) to submissions rates of Patient Family Relations (PFR) Department, a hospital service to address patient/family concerns. Triangulation of quantitative data with thematic analysis of safety concern submissions and patient/carepartner interviews to understand submission content and perspectives on safety reporting. RESULTS: Thirty-two MySafeCare submissions were received with an average rate of 1.7 submissions per 1,000 patient-days and a range of 0.3 to 4.8 submissions per 1,000 patient-days across all units, indicating notable variation between units. MySafeCare submission rates were significantly higher than PFR submission rates during the post-intervention period on the vascular unit (4.3 [95% CI 2.8 – 6.5] versus 1.5 [95% CI 0.7 – 3.1], Poisson) (P=0.01). Overall trends indicated a decrease in PFR submissions after MySafeCare implementation. Triangulated data indicated patients preferred to report anonymously and did not want concerns submitted directly to their care team. CONCLUSIONS: MySafeCare evaluation confirmed the potential value of providing an electronic, anonymous reporting tool in the hospital to capture safety concerns in real-time. Such applications should be tested further as part of patient safety programs