Managing Chloride and Bicarbonate in the Prevention and Treatment of Acute Kidney Injury

A Gradual Positive Bias in Chloride Measurements with a Major Automated Chemistry Platform

BACKGROUND

Chloride is an extracellular anion commonly measured using ion-selective electrode methods standardized to traceable reference materials. This study investigates the gradual appearance of a positive bias in chloride measurements using the Siemens Healthineers Atellica CH platform that was undetectable via routine quality control or proficiency testing.

METHODS

The bias was characterized using retrospective analysis of laboratory values from presumable healthy outpatients (ICD-10 code Z00.00), reference interval verifications, peer group means from the College of American Pathologists' proficiency testing C survey, and a method comparison study with an alternate platform.

RESULTS

Retrospective analysis of patient data (2017-2024) revealed a gradual shift in median patient chloride concentrations distinct from stable trends observed for other electrolytes. In 2024, reference interval verification revealed that 64.3% of chloride results were above the reference interval, even though the verification was successful in 2021. Proficiency testing results were acceptable compared to peer method; however, revealed a mean positive bias of 3.19 mmol/L when compared to other indirect ISE methods (2019-2024). A method comparison with an alternate chemistry platform demonstrated a mean bias of +4.3 mmol/L using remnant patient samples.

CONCLUSIONS

The use of peer targets for quality control and proficiency testing concealed the detection of a gradual drift in chloride measurements in our laboratory. Analysis of aggregate patient data using ICD-10 codes represents a powerful tool for laboratories when assay performance is questioned. These findings highlight the need for vigilant monitoring of assay drift even for routine analytes to avert potential impact on patient care.

Selection of intraoperative fluid for kidney transplantation

The kidney, the most frequently transplanted organ, represents the optimal treatment for end-stage renal disease. Transplanted kidneys are highly vulnerable to perioperative injuries such as hypotension and hypovolemia, which can be influenced by perioperative fluid management. Postoperatively, delayed graft function increases the risk of graft failure. Although adequate volume administration can reduce delayed graft function, the type of intraoperative fluid most likely to benefit and support graft function remains unclear. Traditionally, crystalloids have been the primary choice for fluid management during kidney transplantation. Among these, 0.9% sodium chloride is the most commonly used, as its potassium-free composition minimizes the risk of hyperkalemia in patients with end-stage renal disease. Albumin is not routinely used, whereas synthetic colloids are discouraged owing to their nephrotoxicity. To date, 0.9% sodium chloride has demonstrated fewer advantages compared with balanced crystalloids, particularly regarding acid-base homeostasis, electrolyte balance, and delayed graft function. This review aims to examine the existing evidence on the effect of crystalloids and colloids on postoperative graft function and to recommend an appropriate fluid regimen, including balanced crystalloids, for kidney transplantation.

Development and Characterization of Sodium Bicarbonate-Based Gel for Cytolytic Vaginosis

Background/Objectives: Cytolytic vaginosis or, classically, Doderlein's cytolysis is characterized by significant growth of species of the Lactobacillus genus, which leads to high amounts of lactic acid in the vaginal environment. Lactobacillus crispatus has been proposed as a key pathogen in this clinical condition. The symptomatology of cytolytic vaginosis is commonly confused with that of vulvovaginal candidosis, leading to inadequate and ineffective azole therapies. Nevertheless, historically, the use of sodium bicarbonate intimate baths was an effective way to reduce the symptoms of cytolytic vaginosis. Methods: In this study, four HPMC gel prototypes were developed, containing sodium bicarbonate concentrations ranging from 4% to 7% (w/w). These gels were evaluated for their physicochemical properties, antimicrobial activity, interference with lactobacilli adhering to cells, and cellular and tissue biocompatibility. Results: The gels presented pH values of around 9.0, and osmolality between 706 mOsm/kg (F4) and 1065 mOsm/kg (F7). The viscosity upon heating to physiologic temperature and dilution with simulated vaginal fluid was highly affected by the concentration of sodium bicarbonate. Gels with higher sodium bicarbonate concentrations (F6 and F7) were not shown to be stable in these conditions. All formulations exhibited effective antimicrobial activity against seven L. crispatus strains, with MIC values ranging from 6.25% to 25% (v/v) in terms of dilution. Additionally, the 4% (w/w) gel significantly interfered with the adhesion of L. crispatus to epithelial cells in competition and exclusion assays, reducing adhesion by more than 90% in relation to the control. Cytotoxicity tests on the Hec-1A, HeLa, and VK2/E6E7 cell lines indicated that the F4 and F5 gels demonstrated lower cytotoxicity levels compared to those with higher concentrations. Furthermore, ex vivo assays using porcine vaginal tissue confirmed that the 4% gel was non-toxic at a 25% (v/v) dilution. Conclusions: Based on these results, the 4% (w/w) sodium bicarbonate gel (F4) emerges as a promising therapeutic option for cytolytic vaginosis, offering effective bacterial interference, favourable physicochemical properties, and biocompatibility suitable for vaginal application.

Acetazolamide-Associated Acute Kidney Injury in Critically Ill Pediatric Patients

OBJECTIVE

Our objective was to determine the incidence and risk factors for intravenous acetazolamide-associated acute kidney injury (AKI).

METHODS

We utilized a retrospective cohort study including patients <19 years of age initiated on intravenous acetazolamide while admitted to an ICU. Data collection included patient demographics, clinical variables, acetazolamide dosing, and serum creatinine (SCr) values. Incidence of AKI was assessed per Kidney Disease Improving Global Outcomes criteria. Descriptive statistical analysis and ordinal logistic regression analysis were performed to determine the incidence of AKI and variables associated with AKI.

RESULTS

A total of 868 patients met study criteria (male 55.8%, median age 0.66 years [IQR 0.19, 3.0 years]). Intravenous acetazolamide was administered at 5.1 ± 2.8 mg/kg/dose for a median of 4 doses (IQR 2, 6). Median baseline SCr was 0.28 mg/dL (IQR 0.22, 0.37), corresponding to a creatinine clearance of 115 ± 55 mL/min/1.73 m². Acute kidney injury occurred in 26.8% (n = 233) of patients (stage I = 20.1%, stage II = 3.7%, stage III 3.1%), and no patients received renal replacement therapy. An ordinal logistic regression model identified an increased odds of AKI with cyclosporine, ethacrynic acid, and piperacillin-tazobactam administration.

CONCLUSIONS

Acute kidney injury occurs frequently in critically ill pediatric patients receiving intravenous acetazolamide.

Crystalloid and Colloid Compositions and Their Impact

This manuscript will review crystalloid (hypo-, iso-, and hyper-tonic) and colloid (synthetic and natural) fluids that are available for intravenous administration with a focus on their electrolyte, acid-base, colligative, and rheological effects as they relate to each solution's efficacy and safety. The goal is for the reader to better understand the differences between each fluid and the influence on plasma composition, key organ systems, and their implications when used therapeutically in animals with critical illness.

Sodium bicarbonate gels: a new promising strategy for the treatment of vulvovaginal candidosis

Vulvovaginal candidosis (VVC), caused mainly by the yeast Candida albicans, is the second most prevalent vaginal infection. It has been found to have a large impact on women's quality of life, self-esteem and routines. The prevalence of recurrent vulvovaginal candidosis (RVVC) remains high so the development of alternative treatments is needed. The main objective of this study was to develop and characterize sodium bicarbonate gels to treat VVC. We described key formulation characteristics and analyzed their influence on in vitro performance evaluations. The potential to inhibit Candida albicans's growth, the pH, osmolality, viscosity and rheological performance in contact with vaginal fluid simulant and the bioadhesion's profile (using a vaginal ex vivo porcine model) were studied for all formulations. Among the formulations, formulation C (5% sodium bicarbonate, 1% carbomer and 94% water) was the most effective in inhibiting the C. albicans' growth. This gel presented the same potential (the same MIC 2.5%) to inhibit other etiological agents of VVC (C. glabrata, C. krusei, C. tropicalis and C. parapsilosis) for all species tested. Additionally, sensorial characteristics of gel C were in accord with users' preferences. This gel exhibited physicochemical characteristics acceptable for short term treatments, suggesting good overall performance for the treatment of VVC. Furthermore, Gel C was biocompatible with the HeLa cell line (MTT assay) and was classified as a non-severe irritant in the HET-CAM assay (irritation score 4 ± 1). Overall, gel C was deemed the best performing of the set tested, and suitable for further development.