Clinical judgement vs. evidence-based practice: two models to predict postoperative hematocrit following uncomplicated hysterectomy

BACKGROUND: Hysterectomies are one of the most frequently performed surgical procedures in the United States. There are a wide variety of diagnoses that require a patient to obtain this procedure, but the majority of hysterectomies are performed for benign indications. Currently, gynecologists do not follow a standardized protocol surrounding postoperative laboratory ordering, and healthcare professionals can order a wide range of tests as often as they choose. Extraneous laboratory orders are disruptive to the patients’ well-being and risk their health following surgery. These orders are costly for hospital systems, take up precious time of hospital employees, and influence the course of patient treatment only in extremely rare circumstances. There are few studies that develop exclusion criteria for patients who may not require a laboratory test following surgery. Though systems to predict postoperative hematocrit have been created, they are complicated and difficult to use. The few studies that were performed are yet to be accepted by the medical community, in part because of their limited scope. This study will be the first to incorporate the results of robotic surgery in the analysis. OBJECTIVE: The purpose of this study is to determine concrete parameters to indicate that a patient is in need of postoperative laboratory work and at risk for anemia or transfusion. We aim to develop two comprehensive models that guide surgical practitioners to identify the cases which do not require laboratory data. METHODS: A total of 1027 gynecologic surgeries were performed at Saint Francis Hospital and Medical Center between April 1, 2014 and May 31, 2016. This retrospective study extracted data from EPIC EMR according to 42 variables preconceived to be the leading indicators of postoperative hematocrit and overall healing. Five healthcare professionals were surveyed to identify the variables that influence their postsurgical patient assessments and their decisions to order blood testing. This information was developed into score sheets with differing levels of stringency. Correlation highlighted 14 of the initial 42 variables as contributors to postoperative hematocrit and an equation model was built. Stepwise linear regression was used for univariate and multivariate analyses, from which we created our equation to predict all patients’ postoperative hematocrit. RESULTS: Out of the 1027 initial cases, a total of 602 cases were identified as hysterectomies for benign indications. Survey data gave the highest value to urine output and heart rate as key indicators of postoperative anemia. From the survey data, two clinical scoring sheets with differing stringency were created to guide practitioner laboratory ordering. These sheets gave parameters of heart rate and urine output the largest correlative weight in determining postoperative hematocrit. However, based on regression analysis, parameters of age (AGE), body mass index (BMI), preoperative platelet count (PPC), estimated blood loss during surgery (IO EBL), preoperative hematocrit (PHCT) and postoperative fluid bolus orders (POSTOP FB) proved to be the key variables impacting postoperative hematocrit (POSTOP HCT). These items were translated into the equation: POSTOP HCT = 22.51 – 0.40*POSTOP FB – 0.01*IO EBL + 0.25 PHCT + 0.09*BMI + 0.06*AGE – 0.01*PPC (R-squared = 0.310). CONCLUSIONS: This study aims to decrease superfluous laboratory testing, as well as to contribute to a larger conversation considering the potential merits of clinical judgement in a data-driven healthcare system. We have created a number of comparable strategies in order to reduce the number of unnecessary blood draws: two clinical scoring sheets and an equation. The score sheets indicate when to order additional testing. These sheets are representative of a range of surgical practitioners’ conventional clinical judgement. The equation serves as an evidence-based guide for determining postoperative hematocrit following benign gynecologic surgery. These predictive mechanisms will be validated and a superior method determined as our research continues with prospective application. We eventually expect to use the most accurate mechanism to reduce postoperative blood testing following all surgeries

VUV photo-processing of PAH cations: quantitative study on the ionization versus fragmentation processes

Interstellar polycyclic aromatic hydrocarbons (PAHs) are strongly affected by the absorption of vacuum ultraviolet (VUV) photons in the interstellar medium (ISM), yet the branching ratio between ionization and fragmentation is poorly studied. This is crucial for the stability and charge state of PAHs in the ISM in different environments, affecting in turn the chemistry, the energy balance, and the contribution of PAHs to the extinction and emission curves. We studied the interaction of PAH cations with VUV photons in the 7-20 eV range from the synchrotron SOLEIL beamline, DESIRS. We recorded by action spectroscopy the relative intensities of photo-fragmentation and photo-ionization for a set of eight PAH cations ranging in size from 14 to 24 carbon atoms, with different structures. At photon energies below ~13.6 eV fragmentation dominates for the smaller species, while for larger species ionization is immediately competitive after the second ionization potential (IP). At higher photon energies, all species behave similarly, the ionization yield gradually increases, leveling off between 0.8 and 0.9 at ~18 eV. Among isomers, PAH structure appears to mainly affect the fragmentation cross section, but not the ionization cross section. We also measured the second IP for all species and the third IP for two of them, all are in good agreement with theoretical ones confirming that PAH cations can be further ionized in the diffuse ISM. Determining actual PAH dication abundances in the ISM will require detailed modeling. Our measured photo-ionization yields for several PAH cations provide a necessary ingredient for such models

Students\u27 Knowledge Regarding the Dynamics of HPV at Secular and Christian Colleges

Purpose: No studies have been identified that analyze the association between religious affiliation and college students\u27 awareness of human papillomavirus (HPV) and its possible consequences. The purpose of this study was to investigate the relationship between knowledge of HPV and the type of college (Christian or secular) a student attends. Methods: The study sample included 195 college students, 18 years of age or older, attending either La Sierra University, Loma Linda University, San Bernardino Valley College, or University of La Verne. The survey assessed six areas of know ledge of HPV including general know ledge, natural history and symptoms, risk and transmission, sequelae and consequences, the role of Pap smears and viral detection, and treatment of HPV. The survey consisted of 31 questions with response categories based on a five-point Likert scale. Results: Forty percent of the students were Seventh-day Adventist, 23% were nondenominational Christians, and 17% were Catholics. Only 29% of the respondents indicated they knew how HPV is transmitted and only 23% of the students were familiar with the risk factors of contracting HPV. The majority of college students are poorly educated about the risk factors and routes of transmission ofHPV. Forty-five percent of students surveyed were not aware that HPV can be transmitted through sexual contact. Students attending Christian colleges had more knowledge regarding HPV than students at secular colleges (p=.02). Conclusion: Results of this study indicated a significant lack of knowledge among college students regarding the risks of transmission of HPV, the relationship between Pap smears and cervical cancer, and the consequences ofHPV

How to Determine the Environmental Exposure of PAHs Originating from Biochar

Biochars are obtained by pyrolyzing biomass materials and are increasingly used within the agricultural sector. Owing to the production process, biochars can contain polycyclic aromatic hydrocarbons (PAHs) in the high mg/kg range, which makes the determination of the environmental exposure of PAHs originating from biochars relevant. However, PAH sorption to biochar is characterized by very high (10⁴–10⁶ L/kg) or extreme distribution coefficients (<i>K</i>_D) (>10⁶ L/kg), which makes the determination of exposure scientifically and technically challenging. Cyclodextrin extractions, sorptive bioaccessibility extractions, Tenax extractions, contaminant traps, and equilibrium sampling were assessed and selected methods used for the determination of bioavailability parameters for PAHs in two model biochars. Results showed that: (1) the <i>K</i>_D values of typically 10⁶–10⁹ L/kg made the biochars often act as sinks, rather than sources, of PAHs. (2) Equilibrium sampling yielded freely dissolved concentrations (pg–ng/L range) that were below or near environmental background levels. (3) None of the methods were found to be suitable for the direct measurement of the readily desorbing fractions of PAHs (i.e., bioacessibility) in the two biochars. (4) The contaminant-trap method yielded desorption-resistant PAH fractions of typically 90–100%, implying bioaccessibility in the high μg/kg to low mg/kg range

Faint dwarfs as a test of DM models: WDM vs. CDM

We use high resolution Hydro$+$N-Body cosmological simulations to compare the assembly and evolution of a small field dwarf (stellar mass ~ 10$^{6-7}$ M$\odot$, total mass 10$^{10}$ M$\odot$ in $\Lambda$ dominated CDM and 2keV WDM cosmologies. We find that star formation (SF) in the WDM model is reduced and delayed by 1-2 Gyr relative to the CDM model, independently of the details of SF and feedback. Independent of the DM model, but proportionally to the SF efficiency, gas outflows lower the central mass density through `dynamical heating', such that all realizations have circular velocities $<$ 20kms at 500$~$pc, in agreement with local kinematic constraints. As a result of dynamical heating, older stars are less centrally concentrated than younger stars, similar to stellar population gradients observed in nearby dwarf galaxies. Introducing an important diagnostic of SF and feedback models, we translate our simulations into artificial color-magnitude diagrams and star formation histories in order to directly compare to available observations. The simulated galaxies formed most of their stars in many $\sim$10 Myr long bursts. The CDM galaxy has a global SFH, HI abundance and Fe/H and alpha-elements distribution well matched to current observations of dwarf galaxies. These results highlight the importance of directly including `baryon physics' in simulations when 1) comparing predictions of galaxy formation models with the kinematics and number density of local dwarf galaxies and 2) differentiating between CDM and non-standard models with different DM or power spectra.Comment: 13 pages including Appendix on Color Magnitude Diagrams. Accepted by MNRAS. Added one plot and details on ChaNGa implementation. Reduced number of citations after editorial reques

Public Verification for Private Hash Matching

End-to-end encryption (E2EE) prevents online services from accessing user content. This important security property is also an obstacle for content moderation methods that involve content analysis. The tension between E2EE and efforts to combat child sexual abuse material (CSAM) has become a global flashpoint in encryption policy, because the predominant method of detecting harmful content---server-side perceptual hash matching on plaintext images---is unavailable. Recent applied cryptography advances enable private hash matching (PHM), where a service can match user content against a set of known CSAM images without revealing the hash set to users or nonmatching content to the service. These designs, especially a 2021 proposal for identifying CSAM in Apple\u27s iCloud Photos service, have attracted widespread criticism for creating risks to security, privacy, and free expression. In this work, we aim to advance scholarship and dialogue about PHM by contributing new cryptographic methods for system verification by the general public. We begin with motivation, describing the rationale for PHM to detect CSAM and the serious societal and technical issues with its deployment. Verification could partially address shortcomings of PHM, and we systematize critiques into two areas for auditing: trust in the hash set and trust in the implementation. We explain how, while these two issues cannot be fully resolved by technology alone, there are possible cryptographic trust improvements. The central contributions of this paper are novel cryptographic protocols that enable three types of public verification for PHM systems: (1) certification that external groups approve the hash set, (2) proof that particular lawful content is not in the hash set, and (3) eventual notification to users of false positive matches. The protocols that we describe are practical, efficient, and compatible with existing PHM constructions

In Vitro Assay and Characterization of the Farnesylation-Dependent Prelamin a Endoprotease

The 72-kDa nuclear lamina protein lamin A is synthesized as a 74-kDa farnesylated precursor. Conversion of this precursor to mature lamin A appears to be mediated by a specific endoprotease. Prior studies of overexpressed wild-type and mutant lamin A proteins in cultured cells have indicated that the precursor possesses the typical carboxyl-terminal S- farnesylated, cysteine methyl ester and that farnesylation is required for endoproteolysis to occur. In this report, we describe the synthesis of an S- farnesyl, cysteinyl methyl ester peptide corresponding to the carboxyl- terminal 18 amino acid residues of human prelamin A. This peptide acts as a substrate for the prelamin A endoprotease in vitro, with cleavage of the synthetic peptide at the expected site between Tyr657 and Leu658. Endoproteolytic cleavage requires the S-prenylated cysteine methyl ester and, in agreement with transfection studies, is more active with the farnesylated than geranylgeranylated cysteinyl substrate. N-Acetyl farnesyl methyl cysteine is shown to be a noncompetitive inhibitor of the enzyme. Taken together, these observations suggest that there is a specific farnesyl binding site on the enzyme which is not at the active site