Anion gap physiology and faults of the correction formula

Disclaimer In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. Purpose The anion gap is a calculated fundamental laboratory parameter used to identify and monitor acid-base disturbances. A recently popularized correction formula transforms the resulting integer to compensate for hypoalbuminemia and improve diagnostic yield. Clinical pharmacists should be aware of the underlying biochemistry, interpretation, and limitations of this formula to discern drug- and disease-related etiologies. Summary The anion gap is utilized in most care settings, ranging from outpatient monitoring to inpatient intensive care units. Supported by decades of experience, the original anion gap derives its value from its simplicity. Applying the anion gap in metabolic acidosis can help narrow differential diagnosis and detect concomitant acid-base disorders. To account for hypoalbuminemia and potential missed diagnoses, a correction formula was developed to improve sensitivity. Yet, the law of electroneutrality ensures that hypoalbuminemia is already accounted for in the original anion gap, and the proposed correction formula was derived from samples unrepresentative of human physiology. Evidence from clinical trials shows no benefit from applying the correction formula. Conclusion There is no advantage to correcting the anion gap, and such correction may increase the risk of misinterpretation or error. Clinicians should understand these limitations when diagnosing or trending acid-base disturbances.

Neutrino energy-loss rate in 331β model

We evaluate the stellar energy-loss rates [Formula: see text] due to the production of neutrino pair in 3-3-1 models. The energy loss rate [Formula: see text] is evaluated for different values of [Formula: see text] in which [Formula: see text] is a parameter used to define the charge operator in the 331 models. We show that the contribution of dipole moment to the energy loss rate is small compared to the contribution of new natural gauge boson [Formula: see text]. The correction [Formula: see text] compared with that of Standard Model is evaluated and do not exceed 14% and is highest with [Formula: see text]. Of all the evaluated models, model with [Formula: see text] give a relative large [Formula: see text] correction for the mass of [Formula: see text][Formula: see text] GeV. This mass range is within the searching range for [Formula: see text] boson at LHC.

Is it Possible to Derive the Dresdner Correction Formula Using a Finite Element Program?

Introduction The aim was to construct a model cornea by CAD and finite element software to find out how the intraocular pressure compares to the forces for applanation at the outside of the model cornea. These data were to be compared to the Dresdner correction formula. Thereby, it was possible to find out whether the model was plausible and to find hints as to why a correction for how the intraocular pressure depends on the corneal thickness is necessary at all. Methods Using the open-source software FreeCad and geometrical data for the cornea of the literature, an average cornea was constructed. On this average cornea, a finite element analysis was performed using the free software z88aurora. The intraocular pressure was measured by applanation of the outer cornea. The necessary forces were analysed. Results In this model, the intraocular pressure had to be corrected depending on the corneal thickness. The correction factor was kmean; finite elements = 19.17 – 0.0334*corneal thickness. The necessary correction did not exclusively depend on the relation between the endothelial area and the area of the outer cornea: for this relation alone the correction would have been karea-relation = 1.0361 – 0.0006*corneal thickness. Discussion The model correction formula was close to the Dresdner formula. The relation between endothelial area and the area of the outer cornea could only explain about half of the necessary correction.

Proposal of accurate cup placement procedure during total hip arthroplasty based on pelvic tilt discrepancies in the lateral position

By combining the anatomical-pelvic-plane (APP) positioner with a newly improved navigation system during total hip arthroplasty (THA), it is theoretically possible to determine cup orientation based on the APP while tracking pelvic movement. The purpose of this study was to determine the navigation accuracy and whether the error is related to the pelvic position fixed by the positioner. Fifty hips that underwent primary THA between 2018 and 2020 were analysed. The accuracy was 2.34° at radiographic inclination (RI) and − 5.01° at radiographic anteversion (RA), and the error was within 10° at both RI and RA in only 40 of 50 hips (80.0%). The discrepancy in pelvic sagittal tilt was correlated with the cup orientation error and especially strongly correlated with the RA error (r = − 0.751, p < 0.001). When RI and RA were calculated using a correction formula to determine the true cup orientation based on the pelvic tilt discrepancies, the error in both RI and RA was within 10° in all cases (100%). The navigation accuracy is related to the pelvic position fixed by the positioner, and the correction formula for the target angle that considers pelvic tilt discrepancies can lead to accurate cup placement in the future.

Prevalence of discordant QTc values among cancer patients by the Bazett, Fridericia, and Framingham formulae: Evidence for a standardized approach.

6575 Background: Many chemotherapies have the potential to prolong the QT interval, requiring monitoring of the corrected QT (QTc) to prevent life-threatening arrhythmias. Most clinical guidelines recommend adjusting/holding chemotherapy with Grade 3 or higher toxicity by CTCAE (QTc≥500). Several formulae are used for QTc monitoring including Bazett, Fridericia, and Framingham. The most commonly used formula, Bazett, is well-documented to result in inappropriately high QTc values although the potential impact of this overcorrection on cancer treatment is unknown. We aimed to describe the prevalence of QTc prolongation among cancer patients and the effects on CTCAE adverse event grading by various QTc formulae to determine the potential impact on clinical management. Methods: We performed a single-center retrospective analysis of QT values from electrocardiograms (ECGs) collected January 2010-April 2020 and evaluated associations between QTc values, medications, and patient characteristics. QTc prolonging agents were determined by FDA package insert and cross-referenced with CredibleMeds.org. Results: 20,017 ECGs were evaluated. 18.6% (3,730) met ACC/ACCF/HRS criteria for prolonged QTc by ≥1 QT correction formula (either Bazett, Fridericia, or Framingham). 7.5% (1,494) were prolonged with all three formulae, and 8.6% (1,635) were prolonged only with Bazett. The CTCAE classification using the Bazett formula differed from both Fridericia and Framingham in 37.9% (7,583) of the ECGs. In contrast, Fridericia and Framingham formulae resulted in the same CTCAE classification in 94.5% (18,912). Of 1,789 ECGs classified as Grade 3 toxicity by Bazett, 72.0% (1,288, 6.4% of all ECGs) were classified as Grade 2 or less by both Fridericia and Framingham. 12.0% (2,340) of all ECGs were taken from patients (n = 421) on 24 different QT-prolonging chemotherapies. In 38.8% (909) of the ECGs, the CTCAE classification using the Bazett formula differed from both Fridericia and Framingham while use of Fridericia and Framingham formulae resulted in the same classification in 93.0% (2,176) of the ECGs. Of 293 ECGs classified as Grade 3 toxicity by Bazett, 65.2% (191) were classified as Grade 2 or less by both Fridericia and Framingham. Conclusions: To our knowledge, this is the largest analysis of discrepancies between different QTc formulae in patients receiving chemotherapy. These findings demonstrate an unacceptably high rate of discordance between formulae. Discordant data can lead to inconsistent clinical management and adverse event grading underscoring the urgent need to standardize QTc monitoring and reporting. These findings support the discontinuation of the routine use of the Bazett correction formula among cancer patients as CTCAE Grade 3 reporting from the Bazett formula is unreliable in over 65% of cases.

Dynamic change of serum CA19–9 levels in benign and malignant patients with obstructive jaundice after biliary drainage and new correction formulas

Background CA19–9 is one of the most widely used tumor markers in biliary-pancreatic diseases. The measured value may not factually reflect the genuine CA19–9 level secreted by tumor, which affected by biliary obstruction. There is an urgent need of developing a correction formula of CA19–9 in biliary obstructive patients to guide clinical practice and avoid making improper clinical decision. Methods Clinical characteristics were collected among patients undergoing biliary drainage in our hospital between January 2014 and January 2019. By comparing the malignant and benign patients statistically, dynamic change trend of CA19–9 levels after biliary drainage was obtained. The correction formulas of CA19–9 were generated by means of linear regression. Results 121 patients, including 102 malignant and 19 benign patients, were enrolled in this study. The baseline CA19–9 level of malignant patients is much higher than that of benign patients. Total bilirubin (TB) level was found to be not related with CA19–9 value (p = 0.109). The drop proportion of the average CA19–9 level in the malignant patients (39.2%, IQR -18.4-78.6%) was much lower than that in the benign patients (75.7%, IQR 58.1–86.6%) (p = 0.014). The correction formula, CA19–9True = 0.63 × CA19–9Measured - 20.3 (R2 = 0.693, p<0.001), was generated based on the linear relation between CA19–9 after drainage and CA19–9 before drainage in malignant patients, which had similar diagnostic value with true CA19–9 value. Conclusions Quantitative correction formulas of CA19–9 considering the effect of biliary decompression was first proposed in this study, aiming to provide a more accurate CA19–9 level to make more accurate clinical decision and avoid making improper therapeutic schedule.

PROCESSING RESONANCE SELF-SHIELDING EFFECT OF GADOLINIA BASED ON IMPTOVED SUPERCELL SCHEME

An improved supercell scheme has been proposed in this paper to efficiently and accurately process resonance self-shielding effect of gadolinia. Resonance effects are classified into global shadowing effect and local effects involving resonance interference, spatial self-shielding effects. Two categories of effects are decoupled and treated respectively based on different 1-D cylindrical pins. Hyperfine group method is applied to obtain multi-group cross sections for each 1-D pin. Afterwards, two categories of effects are coupled based on a correction formula. Because of the low efficiency for Carlvik method to compute collision probabilities in hyperfine group method, online tabulation and interpolation method is developed to accelerate gaining collision probabilities. The proposed scheme is verified against the problems of 3×3 pins with gadolinia rod, VERA 2O assembly with 12 gadolinia rods and VERA 2P with 24 gadolinia rods. The numerical results suggest promising consistence of multi-group cross sections and eigenvalues between the proposed scheme and reference solutions.