An evaluation of vancomycin dosing for complicated infections in pediatric patients

Practical approaches to improve vancomycin-related patient outcomes in pediatrics- an alternative strategy when AUC/MIC is not feasible

Background

Anecdotal experience and studies have shown that most pediatric patients fail to reach target therapeutic vancomycin trough levels (VTLs) and required higher total daily doses (TDD). This retrospective study aims to evaluate the frequency of hospitalized children who achieved target VTLs with a vancomycin (VNCO) dosing regimen of 40-60 mg/kg/d q6h and to assess the VNCO-TDD required to attain the target and their effects on clinical outcomes in pediatric patients.

Methods

After ethical approval, patients of 3 month-12 years were evaluated in this chart review study who received ≥ 3 intravenous-VNCO doses and appropriately drawn blood samples of VTLs between October 2019 to June 2020. Data were retrieved for demographic and clinical characteristics, culture reports, VNCO-regimen, subsequent steady-state VTLs, concomitant nephrotoxic medications, and serum creatinine. Clinical pharmacists made interventions in VNCO therapy and higher VNCO-TDD were used. Safety of higher vs standard daily doses and their clinical impact on duration of therapy, hospital stay, and survival were evaluated.

Results

A total of 89 (39.1%) patients achieved target VTLs (SD-group). The smallest proportion (18.2%) of 2–6 years patients achieved target VTLs and reported the lowest mean value of 10.1 ± 0.2 mg/L which was a significant difference (p < 0.05) from all subgroups. Subtherapeutic VTLs were observed in 139 (60.9%) cases (HD-group), who received higher VNCO-TDD of 72 ± 8.9 mg/kg/d q6h to achieve the targets. Duration of therapy in culture-proven septic patients was significantly (p = 0.025) longer in SD-group [18.4 ± 12.2 days] than HD-group [15.1 ± 8.9 days]. Nephrotoxicity and electrolyte imbalance were comparable in groups. Length of hospital stay was significantly (p = 0.011) longer [median 22 (range 8–55) days] in SD-group compared to HD-group [median 16 (range 8–37) days]. Number of patients survived in HD-group were significantly (p = 0.008) higher than SD-group [129 (92.8%) vs 75 (84.3%)].

Conclusion

Initial Vancomycin doses of 72 ± 8.9 mg/kg/day q6h are required to achieve therapeutic target in 3 months to 12 years patients. High doses are not associated with higher nephrotoxicity than reported with low doses. In addition, efficient pharmacist intervention for the use of higher VNCO-TDD may improve clinical outcomes in terms of duration of therapy, hospital stay, and survival.

A Multicenter Retrospective Study of Vancomycin Dosing by Weight Measures in Children

OBJECTIVE

Vancomycin carries risks of treatment failure and emergent resistance with underexposure and renal toxicity with overexposure. Children with overweight or obesity may have altered pharmacokinetics. We aimed to examine how body weight metrics influence vancomycin serum concentrations and to evaluate alternative dosing strategies.

METHODS

This was a multicenter retrospective cohort study across 3 large, academic hospitals. Patients aged 2 to 18 years old who received ≥3 doses of intravenous vancomycin were included. Weight metrics included total body weight, adjusted body weight, ideal body weight, body surface area, and allometric weight. Outcomes included vancomycin concentration and ratios of area under the curve (AUC) to minimum inhibitory concentration (MIC). Regression analyses were used to examine which body-weight identifier predicted outcomes.

RESULTS

Of the 1099 children, 45% were girls, mean age was 9.0 (SD = 5.4) years, 14% had overweight, and 17% had obesity. Seventy-five percent of children had vancomycin concentrations in the subtherapeutic range by trough <10 µg/mL, and 63% had a ratio of AUC to MIC <400 μg-hr/mL. Three percent had a supratherapeutic initial trough >20 µg/mL or ratio of AUC to MIC >600 μg-hr/mL. Serum vancomycin concentrations were higher in children with overweight or obesity compared with children who were at a normal weight or underweight; the mean ratio of AUC to MIC also trended higher in the groups with overweight or obesity.

CONCLUSIONS

Most children received vancomycin regimens that produced suboptimal trough levels. Children with overweight or obesity experienced higher vancomycin trough levels than children of normal weight despite receiving lower total body weight dosing. Using the ratio of AUC to MIC was a better measure of drug exposure.

Pediatric Antibiotic Stewardship: Optimization of Vancomycin Therapy Based on Individual Pharmacokinetics

BACKGROUND

Vancomycin has been a first-line treatment for Gram-positive infections for decades. However, strategies for therapeutic drug monitoring (TDM) and dose-optimization in pediatrics remain controversial. In this study, we analyzed the impact of specific antibiotic stewardship interventions on efficacy and safety of vancomycin therapy.

METHODS

From September 2014 to May 2017, we conducted a prospective study to compare a control and a TDM intervention group in our tertiary care center. As part of an antibiotic stewardship program, we implemented internal guidelines on correct vancomycin dosing, TDM timing, as well as targeted trough level range and installed a pharmacokinetic (PK) consultation service to adapt vancomycin dosing to individually calculated PK parameters. As primary clinical outcomes, the percentage of patients with sustained therapeutic vancomycin trough levels and treatment days with therapeutic vancomycin trough levels, that is, 10-15 mg/L were analyzed. Secondary outcomes included nephrotoxicity, readmission rate and mortality. Median daily dose required to achieve therapeutic trough levels was examined.

RESULTS

Clinical outcomes for 90 control patients were compared with outcomes for 19 patients guided by a PK consultation service. Percentage of patients with sustained therapeutic vancomycin trough levels increased from 17.8% to 94.7% (P < 0.001) and percentage of treatment days with therapeutic vancomycin trough levels increased from 18.4% (117/637) to 665% (155/233, P < 0.001). Readmission rate decreased from 24.4% to 5.3% (P = 0.07). No differences in nephrotoxicity or mortality rate were observed between groups. A median daily dose of 72 mg/kg/d was required to achieve therapeutic trough levels.

CONCLUSIONS

Our data demonstrate that implementation of internal guidelines and a PK consultation service was associated with a profound improvement of vancomycin therapy and, therefore, patient safety.

Impact of the Implementation of a Vancomycin Protocol on Trough Serum Vancomycin Concentrations in a Pediatric Intensive Care Unit

BACKGROUND

Vancomycin is an antibiotic that is widely used in pediatric intensive care, but the safe and effective use of this drug is challenging.

OBJECTIVE

This study aimed to assess the impact of a vancomycin protocol on trough serum concentrations.

METHODS

We conducted a retrospective quasiexperimental study in patients aged ≤ 18 years in intensive care who received vancomycin for at least 5 days. Patients were divided into two groups: before and after a protocol implemented in 2017 that suggested an initial vancomycin dose of 60 mg/kg/day, target serum levels of 15-20 μg/mL, and dose adjustments. We compared patient characteristics, target serum level achievement, and vancomycin levels over time.

RESULTS

Each group contained 65 patients; most were male infants with heart disease as the main reason for hospitalization. Only 29.2% of the patients had pretreatment cultures for bacteria identification recorded, with 1.5% identified as methicillin-resistant Staphylococcus aureus. For the first serum levels, 10.8% of patients in the pre-protocol group and 21.5% in the post-protocol group achieved the 15-20 μg/mL target (p = 0.153); during the first 5 days of treatment, this proportion significantly increased from 52.3 to 73.8% (p = 0.018). We observed a difference between the first and fifth levels: 8.9 μg/mL (95% confidence interval [CI] - 3.1 to 21) pre-protocol and 0.4 μg/mL (95% CI - 6.1 to 6.9) post-protocol (p = 0.175).

CONCLUSIONS

Reaching adequate trough vancomycin concentrations in critically ill pediatric patients remains a challenge, and clinical practice protocols allow better dose adjustment and control even when monitoring technologies are unavailable.

Population pharmacokinetics and dose optimization of vancomycin in neonates

The pharmacokinetics of vancomycin vary among neonates, and we aimed to conduct population pharmacokinetic analysis to determine the optimal dosage of vancomycin in Korean neonates. From a retrospective chart review, neonates treated with vancomycin from 2008 to 2017 in a neonatal intensive care unit (NICU) were included. Vancomycin concentrations were collected based on therapeutic drug monitoring, and other patient characteristics were gathered through electronic medical records. We applied nonlinear mixed-effect modeling to build the population pharmacokinetic model. One- and two-compartment models with first-order elimination were evaluated as potential structural pharmacokinetic models. Allometric and isometric scaling was applied to standardize pharmacokinetic parameters for clearance and volume of distribution, respectively, using fixed powers (0.75 and 1, respectively, for clearance and volume). The predictive performance of the final model was developed, and dosing strategies were explored using Monte Carlo simulations with AUC_0–24 targets 400–600. The patient cohort included 207 neonates, and 900 vancomycin concentrations were analyzed. Only 37.4% of the analyzed concentrations were within trough concentrations 5–15 µg/mL. A one-compartment model with first-order elimination best described the vancomycin pharmacokinetics in neonates. Postmenstrual age (PMA) and creatinine clearance (CLcr) affected the clearance of vancomycin, and model evaluation confirmed the robustness of the final model. Population pharmacokinetic modeling and dose optimization of vancomycin in Korean neonates showed that vancomycin clearance was related to PMA and CLcr, as well as body weight. A higher dosage regimen than the typical recommendation is suggested.

Dose Optimization of Vancomycin Using a Mechanism-based Exposure-Response Model in Pediatric Infectious Disease Patients

PURPOSE

This study aimed to determine the appropriate vancomycin dosage, considering patient size and organ maturation, by simulating the bacterial count and biomarker level for drug administration in pediatric patients with gram-positive bacterial (GPB) infections.

METHODS

Natural language processing for n-gram analysis was used to detect appropriate pharmacodynamic (PD) markers in infectious disease patients. In addition, a mechanism-based model was established to describe the systemic exposure and evaluate the PD marker simultaneously in pediatric patients. A simulation study was then conducted by using a mechanism-based model to evaluate the optimal dose of vancomycin in pediatric patients.

FINDINGS

C-reactive protein (CRP) was selected as a PD marker from an analysis of ~270,000 abstracts in PubMed. In addition, clinical results, including the vancomycin plasma concentrations and CRP levels of pediatric patients (n = 93), were collected from electronic medical records. The vancomycin pharmacokinetic model with allometric scaling and a maturation function was built as a one-compartment model, with an additional compartment for bacteria. Both the effects of vancomycin plasma concentrations on the destruction of bacteria and those of bacteria on CRP production rates were represented by using a maximum achievable effect model (E_max model). Simulation for dose optimization was conducted not only by using the final model but also by exploring the possibility of therapeutic failure based on the MICs of vancomycin for GPB. Clinical cure was defined as when the CRP level fell below the upper limit of the normal range. Our dose optimization simulations suggested a vancomycin dosage of 10 mg/kg every 8 h as the optimal maintenance dose for pediatric patients with a postconceptual age <30 weeks and 10 mg/kg every 6 h for older children, aged up to 12 years. In addition, the MIC of 3 μg/mL was assessed as the upper concentration limit associated with successful vancomycin treatment of GPB infections.

IMPLICATIONS

This study confirmed that the changes in bacterial counts and CRP levels were well described with mechanistic exposure-response modeling of vancomycin. This model can be used to determine optimal empiric doses of vancomycin and to improve therapeutic outcomes in pediatric patients with GPB.

Evaluation of vancomycin initial trough levels in children: A 1-year retrospective study

Background and objectives

Achieving vancomycin therapeutic levels is essential for antibacterial success and resistance prevention. Multiple studies have shown that most of the children fail to reach therapeutic trough levels (10-20 µg/mL). This study aims to determine the frequency of achieving therapeutic vancomycin initial trough levels in children, evaluate the effect of age on that achievement and the mean initial trough levels, and the frequency of supratherapeutic levels.

Methods

Children aged 1 month to 12 years who received three or more vancomycin doses 15 mg/kg every 6 h while admitted at our hospital from February 2016 to January 2017, and had a level before the fourth dose were included. Cases with high baseline serum creatinine, acute kidney injury, and congenital heart disease were excluded.

Results

Out of 75 included cases, one third, 28/75 (37.3%), achieved goal. The lowest frequency was 6/28 (21.4%) of the 2-5 years group, which were statistically less likely to achieve, and had significantly lower mean initial trough than the 1-23 months group (P = 0.026 and 0.013, respectively). Mean initial trough levels were 10.1, 7.3, and 8.2 µg/mL in the 1-23 months, 2-5 years, and 6-12 years groups, respectively (P = 0.014). No supratherapeutic levels were observed.

Conclusion

Vancomycin dose of 60 mg/kg/day is insufficient to attain target levels for most of the children. Children aged 2-5 years are the least likely to achieve and have the lowest mean levels. More intensified doses are warranted to be studied prospectively to identify the most effective empiric dose for children.

Effect of Vancomycin Loading Doses on the Attainment of Target Trough Concentrations in Hospitalized Children

OBJECTIVE

Subtherapeutic vancomycin trough concentrations are common in children and may be associated with suboptimal therapeutic response. Our objective was to determine if vancomycin loading doses safely increase the frequency of target trough attainment in hospitalized children.

METHODS

Patients (≥6 months and <18-years-old) who received a vancomycin loading dose between February 1, 2018, and January 30, 2019, were retrospectively enrolled. These patients were compared to a convenience cohort of patients hospitalized between January 1, 2015, and December 31, 2015, who received vancomycin without a loading dose. Target trough concentrations were defined as >15 mg/dL for invasive infections and >10 mg/dL for non-invasive infections.

RESULTS

A total of 151 patients were enrolled, with 77 in the control arm and 74 in the loading dose arm. There was no significant difference in the frequency of comorbidities or need for intensive care unit admission between the two arms. Those receiving a vancomycin loading dose were older (mean age 9.1 vs 5.2 years, p < 0.0001). Patients given a loading dose achieved higher mean initial trough values (13.0 mg/dL vs 9.2 mg/dL, p < 0.0001), were more likely to have an initial trough at or above target (37.0% vs 10.4%, p = 0.0001), were more likely to reach target trough values at any point during therapy (52.1% vs 32.9%, p = 0.0081), and attained a target trough concentration more quickly (mean 41.1 hours vs 58.8 hours, p = 0.0118). There were no significant differences in the frequency of serum creatinine elevation or oliguria at the end of therapy.

CONCLUSIONS

Vancomycin loading doses may improve the ability to safely obtain target trough values in hospitalized children.

Vancomycin Dosage and Its Association with Clinical Outcomes in Pediatric Patients with Gram-Positive Bacterial Infections

Aim

The aim of this study was to evaluate whether vancomycin trough concentrations at initial steady state are associated with clinical and microbiological outcomes along with vancomycin-related nephrotoxicity in pediatric patients with Gram-positive bacterial (GPB) infections.

Methods

A retrospective cohort study of pediatric patients who received vancomycin for ≥72 hours during 2008–2016 was conducted. Study patients were divided into three cohorts in accordance with their first trough levels at steady state: <5 mg/L (lower-trough), 5–10 mg/L (low-trough), and >10 mg/L (high-trough; reference) cohorts.

Results

Of the 201 patients eligible for study inclusion, 60 patients in the lower- and low-trough cohorts, respectively, were idect 3ntified via propensity score matching and analyzed against 30 high-trough patients in each comparison pair (neonates were excluded due to small sample size). Lower-trough patients were at a greater risk for prolonged therapy, retreatment, and dose adjustment than high-trough patients. Final steady-state troughs remained substantially lower in both the lower- and low-trough cohorts (p<0.001 and p=0.005, respectively), despite greater dose up-titration in the lower-trough cohort and percent change in daily dose in both the lower- and low-trough cohorts than in the high-trough cohort (p<0.001 for all). Clinical cure and death risk, along with the risks of isolation of resistant strains and renal events, were not significantly different between cohorts in both comparison pairs.

Conclusion

Vancomycin troughs of <5 mg/L at initial steady state were associated with significantly compromised clinical outcomes in terms of risk of therapy prolongation, retreatment, and aggressive dose up-titration, compared to >10 mg/L troughs in pediatric patients with GPB infections.

Practice survey on the use of vancomycin in pediatrics in the New Aquitaine region and guidelines of learned societies

INTRODUCTION

Vancomycin is an old antibiotic whose use is still being debated today. The objective of this work was to establish an inventory of the use of vancomycin in the various pediatric and neonatal hospital services in the New Aquitaine region.

MATERIALS AND METHODS

A declaratory practice survey was conducted in 49 pediatric and neonatal hospital units. These practices were compared with the guidelines of several learned societies.

RESULTS

A total of 36 responses could be analyzed: 12 units (33%) used vancomycin in discontinuous administration, 18 (50%) had opted for continuous infusion, and six used it in both modalities (17%). The reported dosages were highly variable. Blood tests were performed by 26 units (72%), but the target values of the trough serum concentration were also highly variable. After dosing, all units reported adjusting the dosage and re-dosing after modification (26/26). Finally, 21 units (58%) reported taking into account the MIC of the possibly isolated bacterium.

CONCLUSION

Our study shows that vancomycin is used in very different ways from one unit to another, within the same region, including in ways not recommended by the main learned societies. Much work remains to be done to determine the optimal dosages of vancomycin in pediatrics, to set the serum trough concentration of vancomycin values, and to determine whether continuous infusion use is comparable to discontinuous administration in terms of efficacy.

Vancomycin Dosing in Children With Overweight or Obesity: A Systematic Review and Meta-analysis

CONTEXT

Vancomycin is a medication with potential for significant harm with both overdosing and underdosing. Obesity may affect vancomycin pharmacokinetics and is increasingly common among children.

OBJECTIVE

We aimed to determine if children with overweight or obesity have increased vancomycin trough concentrations with total body weight (TBW) dosing compared with children with normal weight.

DATA SOURCES

We conducted a search of Medline and Medline In-Process & Other Non-Indexed Citations from 1952 (the year vancomycin was discovered) to November 2017.

STUDY SELECTION

Search terms included vancomycin, body weight, and body composition terms and were limited to children. Studies were reviewed and screened by ≥2 reviewers.

DATA EXTRACTION

The primary outcome was vancomycin level. Data were extracted by 2 reviewers. We performed quality assessment using the Newcastle-Ottawa quality assessment scale.

RESULTS

We identified 271 records. After abstract and full-text screening, we identified 7 studies for full review. Six of the 7 studies used a matched case-control design, although there was significant variation in study methodology. Four of the 7 studies were included in a meta-analysis, which revealed a small but significant difference in vancomycin trough levels between children with normal weight and children with overweight or obesity when dosed by using TBW (N = 521; mean difference 2.2 U [95% confidence interval: 1.0-3.4]).

CONCLUSIONS

High-quality data to guide vancomycin dosing in children with obesity are lacking. More studies evaluating dosing strategies in children with obesity are warranted because using TBW to dose vancomycin may lead to higher vancomycin concentrations and potential toxicity.

Vancomycin Monotherapy May Be Insufficient to Treat Methicillin-resistant Staphylococcus aureus Coinfection in Children With Influenza-related Critical Illness

Background

Coinfection with influenza virus and methicillin-resistant Staphylococcus aureus (MRSA) causes life-threatening necrotizing pneumonia in children. Sporadic incidence precludes evaluation of antimicrobial efficacy. We assessed the clinical characteristics and outcomes of critically ill children with influenza–MRSA pneumonia and evaluated antibiotic use.

Methods

We enrolled children (<18 years) with influenza infection and respiratory failure across 34 pediatric intensive care units 11/2008–5/2016. We compared baseline characteristics, clinical courses, and therapies in children with MRSA coinfection, non-MRSA bacterial coinfection, and no bacterial coinfection.

Results

We enrolled 170 children (127 influenza A, 43 influenza B). Children with influenza–MRSA pneumonia (N = 30, 87% previously healthy) were older than those with non-MRSA (N = 61) or no (N = 79) bacterial coinfections. Influenza–MRSA was associated with increased leukopenia, acute lung injury, vasopressor use, extracorporeal life support, and mortality than either group (P ≤ .0001). Influenza-related mortality was 40% with MRSA compared to 4.3% without (relative risk [RR], 9.3; 95% confidence interval [CI], 3.8–22.9). Of 29/30 children with MRSA who received vancomycin within the first 24 hours of hospitalization, mortality was 12.5% (N = 2/16) if treatment also included a second anti-MRSA antibiotic compared to 69.2% (N = 9/13) with vancomycin monotherapy (RR, 5.5; 95% CI, 1.4, 21.3; P = .003). Vancomycin dosing did not influence initial trough levels; 78% were <10 µg/mL.

Conclusions

Influenza–MRSA coinfection is associated with high fatality in critically ill children. These data support early addition of a second anti-MRSA antibiotic to vancomycin in suspected severe cases.

Steady-state Pharmacokinetics of Vancomycin in Children Admitted to Pediatric Intensive Care Unit of a Tertiary Referral Center

Aims and objectives

Vancomycin is a drug of choice for various gram-positive bacterial (GPB) infections and is largely prescribed to pediatric intensive care unit (PICU) patients. Despite the different pathophysiology of these patients, limited data are available on pharmacokinetics of vancomycin. There are lack of data for critically ill Indian children; hence, study was conducted to assess the steady-state pharmacokinetics in children admitted to PICU.

Materials and methods

Twelve subjects (seven males, five females) aged 1–12 years were enrolled. Vancomycin (dose of 20 mg/kg per 8 hours) was infused for over 1 hour and steady-state pharmacokinetics was performed on day 3. Vancomycin concentrations were measured by the validated liquid chromatography mass spectrometry method. Pharmacokinetic parameters were calculated using Winnonlin (Version 6.3; Pharsight, St. Louis, MO).

Results

The steady-state mean C_ssmax was 40.94 μg/mL (±15.07), and mean AUC_{0–8 hours} was 124.15 μg/mL (±51.27). The mean t_1/2 was 4.82 hours (±2.71), Vd was 12.48 L (±4.43), and Cl was 2.08 mL/minute (±0.89). The mean AUC_0–24 among 12 subjects was 372.44 μg/mL (±153.82). Among 35 measured trough concentrations, 23 (65.71%) were below, 11 (31.43%) were within, and 1 (2.86%) was above the recommended range.

Conclusion

The pharmacokinetic parameters of vancomycin were comparable with previously reported studies. However, recommended trough levels (10–20 μg/mL) were not achievable with current recommended dosing of 60 mg/kg/day.

How to cite this article

Mali NB, Tullu MS, Wandalkar PP, Deshpande SP, Ingale VC, Deshmukh CT, et al. Steady-state Pharmacokinetics of Vancomycin in Children Admitted to Pediatric Intensive Care Unit of a Tertiary Referral Center. IJCCM 2019;23(11):497–502.

Treatment of Methicillin-Resistant Staphylococcus aureus (MRSA) Infections in Children: a Reappraisal of Vancomycin

PURPOSE OF REVIEW

In the last 50 years, vancomycin has been the agent of choice to treat infections due to methicillin-resistant Staphylococcus aureus (MRSA). However, vancomycin treatment failure is not uncommon, even when MRSA strains are fully susceptible to vancomycin. Treatment with vancomycin requires careful monitoring of drug levels as there is a potential for nephrotoxicity. Resistance to clindamycin is not infrequent, which also limits therapeutic options for treating infections due to MRSA in children. This paper reviews the current data on pharmacokinetics and pharmacodynamics and clinical efficacy of vancomycin in children.

RECENT FINDINGS

Resistance to vancomycin in MRSA (MIC >2 mg/L) is infrequent; there is increasing evidence in the literature that vancomycin maybe ineffective against increasing proportion of isolates with MICs between 1 and 2 mg/L. Recent studies and meta-analyses have demonstrated that strains with high vancomycin MICs are associated with poor outcomes especially in patients with bacteremia and deep tissue infections due to MRSA. This gradual increase in vancomycin MIC has been reported as MIC creep or vancomycin heteroresistance. Patients infected with MRSA isolates that exhibit MIC creep experience poorer clinical outcomes, including delayed treatment response, increased mortality, increase rate of relapse, and extended hospitalization. There are limited data to guide vancomycin dosing in children with MRSA. Although the vancomycin area under the curve AUC₂₄/MIC ratio > 400 has been shown to predict clinical efficacy in adults, this relationship has not been documented very well for treatment outcomes in MRSA infections in children. Use of higher vancomycin dosages in attempts to achieve higher trough concentrations has been associated with increased nephrotoxicity. New recently approved antibiotics including ceftaroline, dalbavancin, and tedizolid offer a number of advantages over vancomycin to treat staphylococcal infections: improved antimicrobial activity, superior pharmacokinetics, pharmacodynamics, tolerability, and dosing, including once-daily and weekly regimens, and less need for monitoring drug levels.

Vancomycin Use in a Paediatric Intensive Care Unit of a Tertiary Care Hospital

BACKGROUND

Vancomycin is one of the commonly used anti-microbial drugs in intensive care units (ICUs). Guidelines recommend maintaining therapeutic trough levels of vancomycin (10-20 mg/L). The success of achieving the recommended therapeutic concentration of vancomycin is influenced by several factors, and this is even more complex in children, particularly those admitted in the ICU. Hence, we carried out the present study in children admitted in the ICU who were administered vancomycin.

METHODS

We carried out a chart review of children admitted in the paediatric ICU unit of a tertiary care hospital over a period of 3 years. Information on their demographic factors, diagnoses, duration of hospital stay, vancomycin treatment (dose, frequency and time of administration) and concomitant drugs, and vancomycin trough levels were retrieved. Descriptive statistics were used for representing the demographic factors, and multivariable logistic regression analyses were carried out to assess the determining factors.

RESULTS

One-hundred and two children were identified, of whom 13 had renal dysfunction. Two-hundred and fifty-two vancomycin trough levels were available, of which only 25% were observed in the recommended range (10-20 mg/L) amongst patients without any renal dysfunction and 22% amongst patients with renal dysfunction. Vancomycin was administered intravenously at an average [standard deviation (SD)] dose (mg/dose) of 13 (3.9) mostly either thrice or four times daily. Even in patients receiving vancomycin as a definitive therapy, only 40.9% achieved the recommended trough levels. Lower trough levels were associated with an increased risk of mortality. Nearly 4% of the levels were above 20 mg/L (toxic range). Seven children were suspected to have acute kidney injury (AKI) during the course of therapy where the cumulative vancomycin dose and mortality rate was higher. Only one serum vancomycin level during augmented renal clearance was observed in the recommended range. All the patients received at least one concomitant drug that either had nephrotoxic potential or predominant renal elimination, and use of a greater number of such drugs was associated with an increased risk of AKI.

CONCLUSION

The current vancomycin dosing strategy is ineffective in achieving therapeutic trough levels in children admitted to the ICU. Sub-therapeutic vancomycin trough levels significantly increase the risk of mortality.

Continuous intravenous vancomycin in children with normal renal function hospitalized in hematology-oncology: prospective validation of a dosing regimen optimizing steady-state concentration

Continuous intravenous (IV) infusion has been shown to be the best option to administer vancomycin because of its time-dependent bactericidal activity. Available IV vancomycin dosing guidelines in pediatrics with normal renal function leads to less than 50% of patients achieving a vancomycin serum concentration (Css) in the target range (15-20 mg/L). The primary objective of this study was to prospectively validate an age-based dosing regimen in pediatric oncology-hematology. The secondary objective was to investigate the influence on Css attainment of different variables. A continuous IV dosing nomogram was built by retrospective study (2000-2010) on Bayesian dosing adjustments performed in 161 patients. This study assessed the prospective validation of this age-based nomogram and the influence on Css attainment of variables as the gender, underlying disease (oncology or hematology), and hematopoietic stem cell transplantation (HSCT) before receiving vancomycin therapy. A total of 94 patients aged from 4.3 months to 17.9 years old with normal renal function were eligible for the prospective validation. Fifty-five of those patients (58.5%) achieved the target range of vancomycin Css. There was no significant difference between age groups (P = 0.816) and no influence of gender (P = 0.500). There was a nonsignificant trend to a better target attainment in oncology patients (69.2% vs. hematology 54.4%, P = 0.142) and patients who did not undergo HSCT (63.3% vs. 33.3%, P = 0.031). This study proposed an age-based nomogram prospectively validated which near 60% of patients of each age class achieving the target range of Css.

Prediction of Vancomycin Dose for Recommended Trough Concentrations in Pediatric Patients With Cystic Fibrosis

Vancomycin is a key antibiotic used in the treatment of multiple conditions including infections associated with cystic fibrosis and methicillin-resistant Staphylococcus aureus. The present study sought to develop a model based on empirical evidence of optimal vancomycin dose as judged by clinical observations that could accelerate the achievement of desired trough level in children with cystic fibrosis. Transformations of dose and trough were used to arrive at regression models with excellent fit for dose based on weight or age for a target trough. Results of this study indicate that the 2 proposed regression models are robust to changes in age or weight, suggesting that the daily dose on a per-kilogram basis is determined primarily by the desired trough level. The results show that to obtain a vancomycin trough level of 20 μg/mL, a dose of 80 mg/kg/day is needed. This analysis should improve the efficiency of vancomycin usage by reducing the number of titration steps, resulting in improved patient outcome and experience.

The Impact of Pediatric-Specific Vancomycin Dosing Guidelines: A Quality Improvement Initiative

BACKGROUND AND OBJECTIVES

There are limited data guiding vancomycin dosing practices in the pediatric population to target the goal troughs recommended by national vancomycin guidelines. In this study, we sought to improve adherence to guideline trough targets through a quality improvement intervention.

METHODS

A retrospective analysis was first conducted to assess baseline performance. A multidisciplinary team then developed and implemented a standardized dosing algorithm recommending 15 mg/kg per dose for mild and moderate infections (goal trough: 10-15 µg/mL) and 20 mg/kg per dose for severe infections (goal trough: 15-20 µg/mL), both delivered every 6 hours (maximum single dose: 750 mg). The impact of the intervention was evaluated prospectively using standard statistics and quality improvement methodology. The outcome measures included the percentage of patients with an initial therapeutic trough and the time to therapeutic trough.

RESULTS

A total of 116 patients (49 preintervention, 67 postintervention) were included. Postintervention, there was a significant increase in the percentage of patients with an initial therapeutic trough (6.1% to 20.9%, P = .03) and in the percentage of patients with initial troughs between 10 and 20 µg/mL (8.2% to 40.3%, P < .001). The time to therapeutic trough decreased from 2.78 to 1.56 days (P = .001), with the process control chart showing improved control postintervention. Vancomycin-related toxicity was unchanged by the intervention (6.1% versus 4.5%; P = .70).

CONCLUSIONS

Using quality improvement methodology with standardized higher initial vancomycin doses, we demonstrated improved adherence to national trough guidelines without noted safety detriment.