Serum Vancomycin Concentrations Research Articles

Comparing Two Vancomycin Loading Dose Regimens in Patients With Obesity: A Single-Center Prospective Clinical Trial.

Obesity can significantly influence the pharmacokinetics of several medications, including vancomycin. Consequently, specialized dosing strategies may be required to ensure efficacy and safety in patients with obesity(PwO) requiring treatment with vancomycin. This single-center, prospective study evaluated two vancomycin loading dose regimens in PwO, comparing serum vancomycin concentrations, adverse events, and the impact on renal function. Adult patients weighing over 100 kg were randomized into two study groups. A 20 mg/kg loading dose of vancomycin was administered to both groups, with one group restricted to a maximum dose of 2000 mg (n=33) and the other group receiving up to 4000 mg (n=34). Patients receiving the 4000 mg maximal dose achieved significantly higher median vancomycin concentrations at the initial trough (9.1 mg/L vs. 11.3 mg/L, p=0.0497), mean concentrations at the 7.5-hour interval trough (14.4 mg/L vs. 17.1 mg/L, p=0.0151), and mean concentrations at the post-load peak (23.9 mg/L vs. 30.9 mg/L, p=0.0023), without a corresponding increase in adverse renal outcomes, hospital length of stay, or mortality as compared with the 2000 mg maximum dose group. The study's findings demonstrate that higher vancomycin doses in PwO are safely tolerated and do not result in short-term adverse effects on renal function. This study helps us better understand vancomycin pharmacotherapy in PwO, supporting the need for further research to refine dosing guidelines for these patients.

Comparison of vancomycin assays in patients undergoing hemodialysis

Vancomycin is a glycopeptide antibiotic mainly excreted by glomerular filtration. Therefore, patients undergoing hemodialysis tend to accumulate its crystalline degradation product, which has been associated with cross-reaction in commercial immunoassays. The aim of this study was to assess the performance of two commercial immunoassays for measuring vancomycin levels in patients undergoing hemodialysis. This method-comparison study enrolled patients undergoing hemodialysis at two hospitals in Porto Alegre, Brazil. Vancomycin serum concentrations measured by Chemiluminescent Microparticle Assay (CMIA) and measured by Kinetic Interaction of Microparticles in Solution (KIMS) were compared with Liquid Chromatography coupled with Tandem Mass Spectrometry (LC-MS/MS). A total of 64 samples from 42 patients and 54 samples from 23 patients were included in CMIA and KIMS groups. Both measurements were highly correlated with LC-MS/MS, with Spearman rank correlation coefficient r = 0.840 (p < 0.001) and r = 0.926 (p < 0.001), respectively. No deviation of linearity was observed (p = 0.81 and p = 0.49, respectively). The mean difference between CMIA and LC-MS/MS was -1.19 μg/mL and between KIMS and LC-MS/MS was -2.28 μg/mL. LC-MS/MS measured levels were, on average, 2.64 % higher than CMIA and 8.81 % higher than KIMS. CMIA and KIMS revealed accurate commercial methods to measure vancomycin serum concentrations in patients undergoing hemodialysis.

Recommended doses of endovenous vancomycin are insufficient to achieve therapeutic concentrations in paediatric patients

ObjectivesVancomycin therapeutic drug monitoring is challenging, especially in the paediatric population where evidence is scarce. The main objective of this study was to analyse the achievement of therapeutic concentrations of...

Retrospective Study of Factors Affecting the Accuracy of Predicting Vancomycin Concentrations in Patients Aged 75 Years and Above.

Background and Objectives: The predicted serum concentrations of vancomycin are determined using population pharmacokinetic parameters. However, the accuracy of predicting vancomycin serum concentrations in the older population remains unclear. Therefore, this study aimed to investigate the accuracy of predicting vancomycin serum concentrations and identifying elements that diminish the prediction accuracy in older people. Materials and Methods: A total of 144 patients aged 75 years or older were included. The serum vancomycin concentrations in the patients were predicted based on population pharmacokinetic parameters common in Japan. We examined the accuracy of serum vancomycin concentration prediction in elderly individuals by comparing the predicted and measured serum vancomycin concentrations in each patient. The prediction accuracy was evaluated using the mean prediction error (ME) and mean absolute error of prediction (MAE) calculated from the measured and predicted serum vancomycin concentrations in each patient. Results: The ME for all patients was 0.27, and the 95% CI included 0, indicating that the predicted values were not significantly biased compared to the measured values. However, the predicted serum concentrations in the <50 kg body weight and serum creatinine (Scr) < 0.6 mg/dL groups were significantly biased compared to the measured values. The group with a history of intensive care unit (ICU) admission showed the largest values for the ME and MAE. Conclusions: Our prediction accuracy was satisfactory but tended to be lower in underweight patients, those with low creatinine levels, and patients admitted to the ICU. Patients with multiple of these factors may experience a greater degree of decreased predictive accuracy.

Physiologically Based Pharmacokinetic Modeling of Vancomycin in Critically Ill Neonates: Assessing the Impact of Pathophysiological Changes.

Dosing vancomycin for critically ill neonates is challenging owing to substantial alterations in pharmacokinetics (PKs) caused by variability in physiology, disease, and clinical interventions. Therefore, an adequate PK model is needed to characterize these pathophysiological changes. The intent of this study was to develop a physiologically based pharmacokinetic (PBPK) model that reflects vancomycin PK and pathophysiological changes in neonates under intensive care. PK-sim software was used for PBPK modeling. An adult model (model 0) was established and verified using PK profiles from previous studies. A neonatal model (model 1) was then extrapolated from model 0 by scaling age-dependent parameters. Another neonatal model (model 2) was developed based not only on scaled age-dependent parameters but also on quantitative information on pathophysiological changes obtained via a comprehensive literature search. The predictive performances of models 1 and 2 were evaluated using a retrospectively collected dataset from neonates under intensive care (chictr.org.cn, ChiCTR1900027919), comprising 65 neonates and 92 vancomycin serum concentrations. Integrating literature-based parameter changes related to hypoalbuminemia, small-for-gestational-age, and co-medication, model 2 offered more optimized precision than model 1, as shown by a decrease in the overall mean absolute percentage error (50.6% for model 1; 37.8% for model 2). In conclusion, incorporating literature-based pathophysiological changes effectively improved PBPK modeling for critically ill neonates. Furthermore, this model allows for dosing optimization before serum concentration measurements can be obtained in clinical practice.

Safety and efficacy of intrawound vancomycin powder in the prevention of lumbar surgical site infection: A prospective, double-blind, randomized controlled study.

To evaluate the safety and efficacy of intra-wound vancomycin powder in reducing surgical site infections (SSIs) after spine surgery. A prospective, double-blind, randomized controlled study. Patients who underwent posterior lumbar interbody fusion (PLIF) surgery from May 2021 to September 2022. Patients who underwent posterior lumbar interbody fusion (PLIF) surgery between May 2021 and September 2022 were included. Participants were randomized to the vancomycin treatment or control groups using block randomization (block size 4). Except for baseline and surgical data, the plasma levels of white blood cells, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), aspartate aminotransferase, alanine aminotransferase, and serum vancomycin concentration in the groups were analyzed on postoperative days (PODs) 1, 3, and 5. Vancomycin concentration was measured daily until the drainage tubes were removed. The primary outcomes were the 90-day vancomycin-related adverse reactions and SSI rates. Secondary outcomes were perioperative hematological parameters and vancomycin serum (drain) concentrations. A total of 156 participants (78 each in each group) were analyzed by an independent researcher. The follow-up rate was 91%. All participants were followed up for at least 90 days. The 90-day SSI rate in the vancomycin group was 1.3% (1/78), comprising one case of superficial infection. The SSI rate in the control group was 10.3% (8/78), comprising seven cases of superficial infection and one case of deep infection. Compared with that in the control group, the SSI rate in the vancomycin group was decreased by 87.5%, with a statistically significant difference (RR=0.125, 95% CI=0.016-0.976). Additionally, the vancomycin group demonstrated a statistically significant decrease in serum ESR on POD 3 (P=0.039) and CRP on POD 5 (P=0.024) compared to the control group. The local plasma concentration of vancomycin remained elevated for at least 4 days postoperatively, while the serum concentration of vancomycin remined low. Vancomycin-associated adverse reactions were not observed. Intra-wound application of vancomycin powder is a safe and effective procedure for reducing the risk of SSI during PLIF surgery.

Association between prolonged vancomycin infusion and trough concentrations in children. Retrospective study.

Introduction: This study investigated the serum concentration of vancomycin during prolonged infusion in children. Population and methods: This retrospective cohort study included pediatric patients who received vancomycin from June 2017 to June 2020 at a tertiary referral hospital. The patients were divided into two groups according to infusion strategy, the SII (standard intermittent infusion) group and the PI (prolonged infusion) group. Demographic details, infusion period, serum creatinine, duration of vancomycin therapy, trough concentration of vancomycin, and pediatric intensive care unit stay were reviewed. Differences of the concentrations were measured. Results: Sixty-eight patients were included: 31 in the SII group and 37 in the PI group. The trough concentration of vancomycin was significantly higher in the PI group than in SII group (11.2 mg/L [5.9-13.7] vs. 7 mg/L [3.5- 9.3]; p = 0.02). The target attainment rate was higher in the PI group than in the SII group (59.4% and 19.3%, respectively; p = 0.001). There were no significant differences between the SII and PI groups regarding the peak concentrations of vancomycin, final creatinine and peak creatinine. There were no differences between the SII and PI groups regarding the failure events, PICU stay and duration of vancomycin therapy. The multivariable analysis showed that PI was significantly associated with higher trough serum concentrations of vancomycin (OR = 2.27; p = 0.005). Conclusion: Compared to the SII strategy, the PI strategy may be an optimized option to children with severe infection, as it can achieve higher trough concentrations and target concentration attainment.

In Vitro Performance of a Long-Range Surface Plasmon Hydrogel Aptasensor for Continuous and Real-Time Vancomycin Measurement in Human Serum.

This study investigated the suitability of surface modification for a long-range surface plasmon (LRSP) aptasensor using two different hydrogels, aiming at real-time monitoring of vancomycin (VCM) in undiluted serum and blood. Three different layer structures were formed on a gold surface of LRSP sensor chip using poly[2-methacryloyloxyethyl phosphorylcholine (MPC)-co-N-methacryloyl-(L)-tyrosinemethylester (MAT)] (PMM) and poly[MPC-co-2-ethylhexyl methacrylate (EHMA)-co-MAT] (PMEM). The peptide aptamer for VCM was immobilized in PMM and PMEM via MAT. Among four differently prepared sensor chips, the LRSP hydrogel aptasensor with PMM, referred to as the PMM hydrogel, exhibited the highest sensor output and superior antifouling properties. Following the optimization of the PMM hydrogel preparation conditions, the shelf life of the PMM hydrogel was determined to exceed 2 weeks, and the same sensor chip could be used for 102 days without significant performance deterioration. The PMM hydrogel was then applied for VCM measurement in undiluted serum in vitro, where it demonstrated a limit of detection of 0.098 μM and a dynamic range of 0.18-100 μM, covering the therapeutic range. Additionally, the PMM hydrogel enabled the continuous measurement of various VCM concentrations in serum without rinsing and showed a concentration-dependent output in undiluted blood. These findings underscore the potential of the PMM hydrogel for real-time and direct monitoring of VCM in body fluids.

Determination of vancomycin and meropenem in serum and synovial fluid of patients with prosthetic joint infections using UPLC-MS/MS.

Numerous studies have suggested that intra-articular administration of antibiotics following primary revision surgery may be one of the methods for treating prosthetic joint infection (PJI). Vancomycin and meropenem are the two most commonly used antibiotics for local application. Determining the concentrations of vancomycin and meropenem in the serum and synovial fluid of patients with PJI plays a significant role in further optimizing local medication schemes and effectively eradicating biofilm infections. This study aimed to establish a rapid, sensitive, and accurate ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determining the concentrations of vancomycin and meropenem in human serum and synovial fluid. Serum samples were processed using acetonitrile precipitation of proteins and dichloromethane extraction, while synovial fluid samples were diluted before analysis. Chromatographic separation was achieved in 6min on a Waters Acquity UPLC BEH C18 column, with the mobile phase consisting of 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). Quantification was carried out using a Waters XEVO TQD triple quadrupole mass spectrometer with an electrospray ionization (ESI) source in positive ion mode. The multiple reaction monitoring (MRM) mode was employed to detect the following quantifier ion transitions: 717.95-99.97 (norvancomycin), 725.90-100.04 (vancomycin), 384.16-67.99 (meropenem). The method validation conformed to the guidelines of the FDA and the Chinese Pharmacopoeia. The method demonstrated good linearity within the range of 0.5-50 μg/ml for serum and 0.5-100 μg/ml for synovial fluid. Selectivity, intra-day and inter-day precision and accuracy, extraction recovery, matrix effect, and stability validation results all met the required standards. This method has been successfully applied in the pharmacokinetic/pharmacodynamic (PK/PD) studies of patients with PJI.

Comparison of the Areas Under the Curve of Vancomycin Continuous vs. Intermittent Infusion in Critically Ill Pediatrics: A Randomized Clinical Trial.

Providing data on the superior efficacy of vancomycin administered based on the area under the curve over 24 hours to the minimum inhibitory concentration of vancomycin (AUC24/MIC) is crucial. However, data on dosing and monitoring of vancomycin pharmacokinetics in the pediatric population are limited. Previous findings have showed that intermittent infusion of vancomycin (IIV) may not achieve the desired levels, continous infusions of vancomycin (CIV) reach the desired serum concentration faster than IIV and are associated with reduced nephrotoxicity. This study aimed to compare the serum concentrations, AUC24, clinical variables, and adverse effects of two vancomycin administration methods in the pediatric population. This study was a double-blind, randomized, controlled clinical trial conducted at a tertiary children's teaching hospital. Inclusion criteria were age between 2 months and 15 years and weight less than 67 kilograms, with exclusion criteria including renal impairment. Participants were divided into CIV and IIV groups following distinct administration protocols. Demographic, clinical, and laboratory data, including vancomycin serum concentrations, were compiled. Assessments included pediatric mortality risk, pediatric sequential organ failure assessment, and regular temperature monitoring. Pharmacokinetic analysis was conducted using Monolix software 2023R1. Primary endpoints were vancomycin serum levels and AUC24 between cohorts on day three, with nephrotoxicity and additional adverse drug responses evaluated. Sixty-eight patients in the pediatric intensive care unit (PICU) were allocated to either CIV (33) or IIV (35) for vancomycin treatment. In the CIV group, 82% of patients achieved an AUC24 ≥ 400 mg.h/L, compared to 23% in the IIV group. Continuous infusions of vancomycin demonstrated a greater AUC24 (587.7 ± 184.4 mg.h/L vs. 361.9 ± 113.2 mg.h/L, P < 0.05) compared to IIV. Two cases of nephrotoxicity were reported, one in each group, with mortality and adverse events being comparable between the two groups. This study demonstrated that continuous vancomycin infusion has a higher success rate in safely achieving therapeutic vancomycin levels in PICU patients compared to intermittent vancomycin infusion.

Association between trough serum vancomycin concentration and vancomycin-associated acute kidney injury and 30-day mortality in critically ill elderly adults

BackgroundVancomycin-associated acute kidney injury (VA-AKI) is the most clinically relevant side effect of vancomycin. The objective of this study was to investigate the association between VTC and VA-AKI as well as 30-day mortality in critically ill elderly adults.MethodElderly patients with trough serum vancomycin concentration records(VTC) in the Medical Information Mart-IV (MIMIC-IV) and eICU databases were retrospectively studied.ResultsA total of 3,146 critically ill elderly adults were finally enrolled. The incidence of VA-AKI in the elderly population was 76.5%. Logistic regression analysis revealed significant relationships between VA-AKI and various factors, including VTC, comorbidities, and laboratory indicators, and SOFA, and GCS score. For each mg/L increase, the OR for VA-AKI increased by 2.5%. The association between VTC and 30-day mortality was found to be statistically significant (odds ratio (OR): 1.021, 95% CI: 1.010–1.031), P < 0.001). The Restricted cubic splines (RCS) curves revealed that VTC ranged of 19.67 to 35.72 mg/l for AKI and 19.17 to 42.86 mg/l for 30-day mortality exhibit OR with 95% CI above 1, indicating statistically significant associations with an increased risk of AKI and 30-day mortality, respectively. In the subgroup analysis, VTC was identified as a risk factor for VA-AKI in specific patient groups, including white individuals, female patients, those with shock, patients with SOFA > 6, patients with baseline creatinine > 1.2 mg/dl and patients with or without exposed to other nephrotoxic medications.ConclusionThis study found the significant association between VTC and the incidence of VA-AKI and 30-day mortality in critically ill elderly adults. The RCS curves indicated concentration ranges for AKI (19.67–35.72 mg/L) and 30-day mortality (19.17–42.86 mg/L), signifying increased risk.

Development of a model to predict vancomycin serum concentration during continuous infusion of vancomycin in critically ill pediatric patients.

Vancomycin is a frequently used antibiotic in intensive care units, and the patient's renal clearance affects the pharmacokinetic characteristics of vancomycin. Several advantages have been reported for vancomycin continuous intravenous infusion, but studies on continuous dosing regimens based on patients' renal clearance are insufficient. The aim of this study was to develop a vancomycin serum concentration prediction model by factoring in a patient's renal clearance. Children admitted to our institution between July 1, 2021, and July 31, 2022 with records of continuous infusion of vancomycin were included in the study. Sex, age, height, weight, vancomycin dose by weight, interval from the start of vancomycin administration to the time of therapeutic drug monitoring sampling, and vancomycin serum concentrations were analyzed with the linear regression analysis of the mixed effect model. Univariable regression analysis was performed using the vancomycin serum concentration as a dependent variable. It showed that vancomycin dose (p < 0.001) and serum creatinine (p = 0.007) were factors that had the most impact on vancomycin serum concentration. Vancomycin serum concentration was affected by vancomycin dose (p < 0.001) and serum creatinine (p = 0.001) with statistical significance, and a multivariable regression model was obtained as follows: Vancomycin serum concentration (mg/l) = -1.296 + 0.281 × vancomycin dose (mg/kg) + 20.458 × serum creatinine (mg/dl) (adjusted coefficient of determination, R2 = 0.66). This prediction model is expected to contribute to establishing an optimal continuous infusion regimen for vancomycin.

Impact of physical build on serum vancomycin concentrations of patients undergoing hemodialysis: A retrospective cohort study at an acute care hospital

IntroductionEstimating the serum vancomycin (VCM) concentrations of lean and patients with obesity is challenging. Additionally, VCM dosing for Japanese patients undergoing hemodialysis remains particularly unclear. This study aimed to determine the impact of the physical build on serum VCM concentrations of Japanese patients undergoing hemodialysis. MethodsThis retrospective cohort study included hospitalized patients undergoing hemodialysis, who received treatment with VCM between May 1, 2019, and December 31, 2021, at Kansai Rosai Hospital, which is a 642-bed acute care hospital in Japan. Patients were divided into the following three groups based on their body mass index (BMI): lean group (≤18.5 kg/m2), normal group (18.5–25 kg/m2), and obese group (≥25 kg/m2). The VCM dose and predialysis serum VCM concentration (PVC) were compared. ResultsThis study included 191 patients. There were 50 patients in the lean group, 85 in the normal group, and 56 in the obese group. The median loading doses per body weight were 24.0, 22.1, and 21.2 mg/kg for the lean, normal, and obese groups, respectively. The VCM dose per body weight decreased significantly with increasing BMI. The median PVCs of the lean and normal groups were approximately 15 mg/L (not significantly different). However, the median PVC of the obese group was 18.3 mg/L, which was significantly higher (P < 0.001). ConclusionsThe VCM dose per body weight for Japanese patients undergoing hemodialysis should be adjusted based on the BMI.

Model-Informed Precision Dosing Improves Outcomes in Patients Receiving Vancomycin for Gram-Positive Infections.

Consensus guidelines for dosing and monitoring of vancomycin recommend collection of 2 serum concentrations to estimate an area under the curve/minimum inhibitory concentration ratio (AUC/MIC). Use of Bayesian software for AUC estimation and model-informed precision dosing (MIPD) enables pre-steady state therapeutic drug monitoring using a single serum concentration; however, data supporting this approach are limited. Adult patients with culture-proven gram-positive infections treated with vancomycin ≥72 hours receiving either trough-guided or AUC-guided therapy were included in this retrospective study. AUC-guided therapy was provided using MIPD and single-concentration monitoring. Treatment success, vancomycin-associated acute kidney injury (VA-AKI), and inpatient mortality were compared using a desirability of outcome ranking analysis. The most desirable outcome was survival with treatment success and no VA-AKI, and the least desirable outcome was death. The study population (N = 300) was comprised of an equal number of patients receiving AUC-guided or trough-guided therapy. More patients experienced the most desirable outcome in the AUC-guided group compared to the trough-guided group (58.7% vs 46.7%, P = .037). Rates of VA-AKI were lower (21.3% vs 32.0%, P = .037) and median hospital length of stay was shorter (10 days [interquartile range {IQR}, 8-20] vs 12 days [IQR, 8-25]; P = .025) among patients receiving AUC-guided therapy. AUC-guided vancomycin therapy using MIPD and single-concentration monitoring improved outcomes in patients with culture-proven gram-positive infections. Safety was improved with reduced incidence of VA-AKI, and no concerns for reduced efficacy were observed. Moreover, MIPD allowed for earlier assessment of AUC target attainment and greater flexibility in the collection of serum vancomycin concentrations.

Association of piperacillin and vancomycin exposure on acute kidney injury during combination therapy.

Acute kidney injury (AKI) is a well-documented adverse effect observed with piperacillin/tazobactam in combination with vancomycin. The pharmacokinetics of these antibiotics when given in combination have not been previously evaluated. The purpose of this study was to compare the exposure of vancomycin + piperacillin/tazobactam in patients with and without AKI. Ninety adult patients, who received at least 72 h of vancomycin + piperacillin/tazobactam combination therapy and had available serum concentrations of vancomycin and piperacillin were included in the study. Nephrotoxicity was defined as a 1.5-fold increase in serum creatinine within 7 days from baseline. Median daily AUCs were calculated in those with nephrotoxicity (vancomycin + piperacillin/tazobactam 'N') versus those without nephrotoxicity (vancomycin + piperacillin/tazobactam 'WN') during the first 7 days of combination therapy. The overall incidence of AKI in those receiving vancomycin + piperacillin/tazobactam was 20% (18/90). The median daily vancomycin AUCs did not differ between the vancomycin + piperacillin/tazobactam 'WN' and vancomycin + piperacillin/tazobactam 'N' groups. Although not statistically significant, the median daily vancomycin AUCs in the vancomycin + piperacillin/tazobactam 'N' group were numerically greater on Day 5 and trended downwards thereafter. For the piperacillin group, the median daily AUCs did not vary between groups, except on Day 7 where the vancomycin + piperacillin/tazobactam 'WN' group had statistically greater median piperacillin AUC than the vancomycin + piperacillin/tazobactam 'N' group (P = 0.046). Utilizing serum creatinine-defined AKI, our study did not find any significant differences in vancomycin and piperacillin/tazobactam exposure between the groups with and without nephrotoxicity. These data indicate that vancomycin + piperacillin/tazobactam should not be avoided due to the risk of overexposure; instead, clinicians should continue to use these therapies cautiously.

Toward Model-Based Informed Precision Dosing of Vancomycin in Hematologic Cancer Patients: A First Step.

There is no consensus on the optimal vancomycin dose to achieve pharmacokinetic/pharmacodynamic (PK/PD) target in patients with hematologic cancer or in hematopoietic stem cell transplant (HSCT) recipients. A 24-h area under the concentration-time curve (AUC) >400 mg*h/L must be achieved early for successful treatment of severe methicillin-resistant Staphylococcus aureus (MRSA) infections. Current nomograms derived from general population data are not sufficiently accurate to allow AUC-based model-informed precision dosing. The objective of this study was to characterize vancomycin PK in patients with hematologic cancer or in HSCT recipients and to develop a model-informed dosing tool based on PK/PD target requirements. Pooled retrospective and prospective vancomycin serum concentrations were analyzed using NONMEM® to evaluate the performance of previously published population PK (popPK) models built from hematologic cancer datasets and to develop a novel Bayesian PK model. Patients' characteristics and clinical data were tested as potential covariates. The popPK model was validated internally and externally. Predictions of vancomycin concentrations for different dosing regimens were made using Monte-Carlo simulations, and a nomogram strategy was proposed according to selected probability of target attainment (PTA). The predictive performance of the published popPK models was found to be suboptimal for our population. A novel popPK model was developed using 240 vancomycin concentrations (60 patients). A two-compartment structural model with an additive error model best described the data. Ideal body weight and estimated glomerular filtration rate (eGFR) [Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)] were selected as covariates for volume of distribution (V) and clearance (CL). Bootstrapping confirmed the stability and precision of the popPK parameters. The volume of distribution was V1=46.8 L and V2=56.1L, while CL=5.63L/h. External validation using 107 vancomycin concentrations (24 patients) demonstrated the predictivity of the model. A nomogram was developed to reach minimally PTA >50% for 400 < AUC < 600 mg*h/L. To our knowledge, this study provides the first model-informed AUC-based strategy in North American hematologic cancer patients with or without HSCT. The resulting nomogram generated provides a simplified approach to improving the accuracy of initial vancomycin dosing in this population.

Model-Informed Vancomycin Dosing Optimization to Address Delayed Renal Maturation in Infants and Young Children with Critical Congenital Heart Disease.

Ensuring safe and effective drug therapy in infants and young children often requires accounting for growth and organ development; however, data on organ function maturation are scarce for special populations, such as infants with congenital diseases. Children with critical congenital heart disease (CCHD) often require multiple staged surgeries depending on their age and disease severity. Vancomycin (VCM) is used to treat postoperative infections; however, the standard pediatric dose (60-80 mg/kg/day) frequently results in overexposure in children with CCHD. In this study, we characterized the maturation of VCM clearance in pediatric patients with CCHD and determined the appropriate dosing regimen using population pharmacokinetic (PK) modeling and simulations. We analyzed 1,254 VCM serum concentrations from 152 postoperative patients (3 days-13 years old) for population PK analysis. The PK model was developed using a two-compartment model with allometrically scaled body weight, estimated glomerular filtration rate (eGFR), and postmenstrual age as covariates. The observed clearance in patients aged ≤ 1 year and 1-2 years was 33% and 40% lower compared with that of non-CCHD patients, respectively, indicating delayed renal maturation in patients with CCHD. Simulation analyses suggested VCM doses of 25 mg/kg/day (age ≤ 3 months, eGFR 40 mL/min/1.73 m2 ) and 35 mg/kg/day (3 months < age ≤ 3 years, eGFR 60 mL/min/1.73 m2 ). In conclusion, this study revealed delayed renal maturation in children with CCHD, could be due to cyanosis and low cardiac output. Model-informed simulations identified the lower VCM doses for children with CCHD compared with standard pediatric guidelines.

Vancomycin removal and pharmacokinetics during accelerated venovenous hemofiltration.

Vancomycin pharmacokinetics are affected by renal replacement therapy and physiologic changes in critically ill patients. Literature regarding vancomycin removal and pharmacokinetics during accelerated venovenous hemofiltration (AVVH), a form of prolonged intermittent renal replacement therapy, is limited. To describe the removal and pharmacokinetics of vancomycin during AVVH. Eighteen critically ill adults receiving vancomycin and AVVH were included. Vancomycin serum concentrations were obtained within 4 h before and 2-6 h after the AVVH session. Patients' serum concentrations were plotted against time, and individual pharmacokinetic parameters were determined by a one-compartmental analysis. Continuous data are reported as a median (interquartile range [IQR]) and categorical data as a percentage. The median AVVH effluent rate was 39.3 mL/kg/h (IQR 35.5-48 mL/kg/h) for a duration of 9 h (IQR 8-9.75 h). AVVH decreased vancomycin concentrations by 29.8% (IQR 24.9%-35.9%), at a rate of 3.4% per hour (IQR 3.1%-4.3% per hour) of AVVH. The vancomycin elimination rate constant and half-life were 0.039 h-1 (IQR 0.036-0.053 h-1 ) and 17.6 h (IQR 13.1-18.8 h), respectively. The area under the curve during AVVH was 171.7 mg*h/L (IQR 149.1-190 mg*h/L). The volume of distribution in 10 patients was 1 L/kg (IQR 0.73-1.1 L/kg). After AVVH, vancomycin 1000 mg (IQR 750-1000 mg) was needed to maintain a serum trough concentration ≥15 mg/L. Vancomycin is significantly removed by AVVH, which requires supplemental dosing after completion of the AVVH session to maintain desired serum concentrations. Therapeutic drug monitoring of vancomycin serum concentrations is recommended for patients undergoing AVVH.

Comparison of Vancomycin Trough-Based and 24-Hour Area Under the Curve Over Minimum Inhibitory Concentration (AUC/MIC)-Based Therapeutic Drug Monitoring in Pediatric Patients.

Vancomycin 24-hour area under the curve over minimum inhibitory concentration (AUC/MIC) monitoring has been recommended over trough-based monitoring in pediatric patients. This study compared the proportion of target attainment between vancomycin AUC/MIC and trough-based methods, and identified risk factors for subtherapeutic initial extrapolated targets. This was a retrospective, observational study conducted at KK Women's and Children's Hospital (KKH), Singapore. Patients aged 1 month to 18 years with stable renal function who received intravenous vancomycin between January 2014 and October 2017, with at least 2 vancomycin serum concentrations obtained after the first dose of vancomycin, were included. Using a pharmacokinetic software, namely Adult and Pediatric Kinetics (APK), initial extrapolated steady-state troughs and 24-hour AUC were determined by using a one-compartmental model. Statistical tests included Wilcoxon rank sum test, McNemar test, logistic regression, and classification and regression tree (CART) analysis. Of the 82 pediatric patients included, a significantly larger proportion of patients achieved therapeutic targets when the AUC/MIC-based method (24, 29.3%) was used than with the trough-based method (9, 11.0%; p < 0.01). Patients with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 or with age <13 years had an increased risk of obtaining subtherapeutic targets. However, empiric vancomycin doses of 60 mg/kg/day would be sufficient to achieve serum therapeutic targets, using the AUC/MIC-based method. The AUC/MIC-based vancomycin monitoring may be preferred because a larger proportion of patients could achieve initial therapeutic targets. Future prospective studies with larger sample size will be required to determine the optimal vancomycin strategy for pediatric patients.

Effectiveness of a low trough serum concentration of vancomycin on acute kidney injury in infants and toddlers in the paediatric intensive care unit

ObjectiveThis study aimed to assess the effectiveness of a low trough serum concentration of vancomycin on acute kidney injury in infants and toddlers in the paediatric intensive care unit (PICU).MethodsA...