[Augmented renal clearance in critically ill patients: incidence, associated factors and effects on vancomycin treatment]

Determining steady-state trough range in vancomycin drug dosing using machine learning

BACKGROUND

Vancomycin is a renally eliminated, nephrotoxic, glycopeptide antibiotic with a narrow therapeutic window, widely used in intensive care units (ICU). We aimed to predict the risk of inappropriate vancomycin trough levels and appropriate dosing for each ICU patient.

METHODS

Observed vancomycin trough levels were categorized into sub-therapeutic, therapeutic, and supra-therapeutic levels to train and compare different classification models. We included adult ICU patients (≥ 18 years) with at least one vancomycin concentration measurement during hospitalization at Mayo Clinic, Rochester, MN, from January 2007 to December 2017.

RESULT

The final cohort consisted of 5337 vancomycin courses. The XGBoost models outperformed other machine learning models with the AUC-ROC of 0.85 and 0.83, specificity of 53% and 47%, and sensitivity of 94% and 94% for sub- and supra-therapeutic categories, respectively. Kinetic estimated glomerular filtration rate and other creatinine-based measurements, vancomycin regimen (dose and interval), comorbidities, body mass index, age, sex, and blood pressure were among the most important variables in the models.

CONCLUSION

We developed models to assess the risk of sub- and supra-therapeutic vancomycin trough levels to improve the accuracy of drug dosing in critically ill patients.

Estimated glomerular filtration rate as a tool for early identification of patients with insufficient exposure to beta-lactam antibiotics in intensive care units

BACKGROUND

Only about 50% of intensive care unit (ICU) patients reach a free trough concentration above MIC (100% fT > MIC) of beta-lactam antibiotics. Although dose adjustments based on therapeutic drug monitoring (TDM) could be beneficial, TDM is not widely available. We investigated serum creatinine-based estimated GFR (eGFR) as a rapid screening tool to identify ICU patients at risk of insufficient exposure.

METHOD

Ninety-three adult patients admitted to four ICUs in southeast Sweden treated with piperacillin/tazobactam, meropenem, or cefotaxime were included. Beta-lactam trough concentrations were measured. The concentration target was set to 100% fT > MICECOFF (2, 4, and 16 mg/L based on calculated free levels for meropenem, cefotaxime, and piperacillin, respectively). eGFR was primarily determined via Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) and compared to three other eGFR equations. Data was analysed using logistic regression and receiver operative characteristic (ROC) curves.

RESULTS

With intermittent standard dosing, insufficient exposure was common in patients with a relative eGFR ≥48mL/min/1.73m2 [85%, (45/53)], particularly when treated with cefotaxime [96%, (24/25)]. This eGFR cut-off had a sensitivity of 92% and specificity of 82% (AUC 0.871, p < 0.001) in identifying insufficient exposure. In contrast, patients with eGFR <48mL/min/1.73m2 had high target attainment [90%, (36/40)] with a wide variability in drug exposure. There was no difference between the four eGFR equations (AUC 0.866-0.872, cut-offs 44-51 ml/min/1.73m2).

CONCLUSION

Serum creatinine-based eGFR is a simple and widely available surrogate marker with potential for early identification of ICU patients at risk of insufficient exposure to piperacillin, meropenem, and cefotaxime.

The Impact of Augmented Renal Clearance on Vancomycin Pharmacokinetics and Pharmacodynamics in Critically Ill Patients

Augmented renal clearance (ARC), defined as a creatinine clearance (CrCl) > 130 mL/min/1.73 m2, is observed in 30-65% of critically ill patients. When following standard dosage guidelines, patients with ARC often experience subtherapeutic vancomycin levels, resulting in treatment failure due to accelerated drug elimination. This review aims to explore ARC's impact on vancomycin pharmacokinetics and pharmacodynamics (PK/PD) indices in ARC patients, seeking to identify an accurate dose adjustment method for this patient population. In September 2023, a comprehensive literature search was conducted on the MEDLINE and EMBASE databases to include all available studies providing information on the impact of ARC on vancomycin therapy in critically ill adults. Articles that studied the pediatric population and those with insufficient PK data were excluded. A total of 21 articles met the inclusion criteria. The findings revealed a positive correlation between CrCl and vancomycin clearance, indicating low serum concentrations. Therefore, upward dosing adjustments are necessary to improve treatment success. Younger age consistently emerged as a major contributor to ARC and vancomycin PK/PD alterations. This study summarizes the PK/PD alterations, current dosage recommendations and proposes preliminary recommendations on possible dosing approaches to decrease the risk of subtherapeutic exposure in this patient population.

Population pharmacokinetics of a combination of miltefosine and paromomycin in Eastern African children and adults with visceral leishmaniasis

OBJECTIVES

To improve visceral leishmaniasis (VL) treatment in Eastern Africa, 14- and 28-day combination regimens of paromomycin plus allometrically dosed miltefosine were evaluated. As the majority of patients affected by VL are children, adequate paediatric exposure to miltefosine and paromomycin is key to ensuring good treatment response.

METHODS

Pharmacokinetic data were collected in a multicentre randomized controlled trial in VL patients from Kenya, Sudan, Ethiopia and Uganda. Patients received paromomycin (20 mg/kg/day for 14 days) plus miltefosine (allometric dose for 14 or 28 days). Population pharmacokinetic models were developed. Adequacy of exposure and target attainment of paromomycin and miltefosine were evaluated in children and adults.

RESULTS

Data from 265 patients (59% ≤12 years) were available for this pharmacokinetic analysis. Paromomycin exposure was lower in paediatric patients compared with adults [median (IQR) end-of-treatment AUC0-24h 187 (162-203) and 242 (217-328) µg·h/mL, respectively], but were both within the IQR of end-of-treatment exposure in Kenyan and Sudanese adult patients from a previous study. Cumulative miltefosine end-of-treatment exposure in paediatric patients and adults [AUCD0-28 517 (464-552) and 524 (456-567) µg·day/mL, respectively] and target attainment [time above the in vitro susceptibility value EC90 27 (25-28) and 30 (28-32) days, respectively] were comparable to previously observed values in adults.

CONCLUSIONS

Paromomycin and miltefosine exposure in this new combination regimen corresponded to the desirable levels of exposure, supporting the implementation of the shortened 14 day combination regimen. Moreover, the lack of a clear exposure-response and exposure-toxicity relationship indicated adequate exposure within the therapeutic range in the studied population, including paediatric patients.

Creatinine Clearance in Acute Brain Injury: A Comparison of Methods

BACKGROUND

Currently, the measurement of glomerular filtration rate is very complex and costly, so its daily evaluation is performed using endogenous markers, of which creatinine is the most frequently used. It allows the estimation of glomerular filtration rate by means of its clearance or by formulas based on its serum and urine concentration. Augmented renal clearance (ARC) is frequent among critically ill patients and is defined as creatinine clearance (CrCl) > 130 ml/min/1.73 m2. The aim of this study was to compare measured CrCl (MCC) and estimated CrCl obtained with the Cockcroft-Gault formula (CG), the Modification of Diet in Renal Disease Study equation (MDRD), and the Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI) in patients with severe traumatic brain injury and nontraumatic subarachnoid hemorrhage. The second aim was to assess the incidence of ARC in this population of neurocritical patients.

METHODS

This was a prospective, observational, single center study from a cohort of 74 patients admitted to the neurocritical intensive care unit due to traumatic brain injury or subarachnoid hemorrhage. Serum creatinine (at 7 a.m.) and a 6-h urine collection were analyzed, and CrCl was measured and estimated by using CG, MDRD, and CKD-EPI. The intraclass correlation coefficient (ICC) was evaluated for each pair, and Bland-Altman plots were used to assess clinical significance.

RESULTS

Among 74 patients, the median age was 53 (interquartile range [IQR] 36-65), and the median Glasgow Coma Scale score at admission was 6. The median MCC at admission was 176 (IQR 135-214). The medians of CG, MDRD and CKD-EPI were, respectively, 129 ml/min/1.73 m2 (IQR 95-176), 158 (IQR 115-202), and 116 (97-132). An ICC was applied to evaluate the correlation between MCC and estimated methods and showed a weak correlation between MCC and estimated CrCl obtained with the three different methods. The strongest ICC statistical correlation was found between MCC and MDRD, and the weakest correlation was found between MCC and CKD-EPI. Bland-Altman plots showed that differences between each pair were not clinically acceptable. ARC was present in 78% of measurements, using MCC. A weak correlation was observed between MCC and calculated CrCl. CG, MDRD, and CKD-EPI overestimated MCC when MCC ≤ 130 ml/min/1.73 m2 and underestimated it when MCC > 130 ml/min/1.73 m2.

CONCLUSIONS

In this population, there was a weak statistical correlation between measured and estimated methods. In patients with ARC, formulas underestimated MCC. MCC should probably be the preferred methodology for renal function assessment in the clinical setting to better adjust drug dosage and guarantee drug effectiveness.

Individualized antibiotic dosage regimens for patients with augmented renal clearance

Objectives: Augmented renal clearance (ARC) is a state of enhanced renal function commonly observed in 30%-65% of critically ill patients despite normal serum creatinine levels. Using unadjusted standard dosing regimens of renally eliminated drugs in ARC patients often leads to subtherapeutic concentrations, poor clinical outcomes, and the emergence of multidrug-resistant bacteria. We summarized pharmaceutical, pharmacokinetic, and pharmacodynamic research on the definition, underlying mechanisms, and risk factors of ARC to guide individualized dosing of antibiotics and various strategies for optimizing outcomes. Methods: We searched for articles between 2010 and 2022 in the MEDLINE database about ARC patients and antibiotics and further provided individualized antibiotic dosage regimens for patients with ARC. Results: 25 antibiotic dosage regimens for patients with ARC and various strategies for optimization of outcomes, such as extended infusion time, continuous infusion, increased dosage, and combination regimens, were summarized according to previous research. Conclusion: ARC patients, especially critically ill patients, need to make individualized adjustments to antibiotics, including dose, frequency, and method of administration. Further comprehensive research is required to determine ARC staging, expand the range of recommended antibiotics, and establish individualized dosing guidelines for ARC patients.

Prevalence of Augmented Renal Clearance (ARC), Utility of Augmented Renal Clearance Scoring System (ARC score) and Augmented Renal Clearance in Trauma Intensive Care Scoring System (ARCTIC score) in Predicting ARC in the Intensive Care Unit: Proactive Study

Objectives

We aimed to study the prevalence of augmented renal clearance (ARC) and validate the utility of ARC and ARCTIC scores. We also aimed to assess the correlation and agreement between estimated GFR (eGFR-EPI) and 8-hour measured creatinine clearance (8 hr-mCL_cr).

Study design and methodology

This was a prospective, observational study done in the mixed medical-surgical intensive care unit (ICU) and 90 patients were recruited. 8 hr-mCL_cr, ARC, and ARCTIC scores and eGFR-EPI were calculated for all patients. ARC was said to be present if 8 hr-mCLcr was ≥ 130 mL/min.

Results

Four patients were excluded from the analysis. The prevalence of ARC was 31.4%. The sensitivity, specificity, and positive and negative predictive values of ARC and ARCTIC scores were found to be 55.6, 84.7, 62.5, 80.6, and 85.2, 67.8, 54.8, and 90.9 respectively. AUROC for ARC and ARCTIC scores were 0.802 and 0.765 respectively. A strong positive correlation and poor agreement were observed between eGFR-EPI and 8 hr-mCL_cr.

Conclusion

The prevalence of ARC was significant and the ARCTIC score showed good potential as a screening tool to predict ARC. Lowering the cut-off of ARC score to ≥5 improved its utility in predicting ARC. Despite its poor agreement with 8 hr-mCL_cr, eGFR-EPI with a cut-off ≥114 mL/min showed utility in predicting ARC.

How to cite this article

Kanna G, Patodia S, Annigeri RA, Ramakrishnan N, Venkataraman R. Prevalence of Augmented Renal Clearance (ARC), Utility of Augmented Renal Clearance Scoring System (ARC score) and Augmented Renal Clearance in Trauma Intensive Care Scoring System (ARCTIC score) in Predicting ARC in the Intensive Care Unit: Proactive Study. Indian J Crit Care Med 2023;27(6):433-443.

Critically Ill Patients with Renal Hyperfiltration: Optimizing Antibiotic Dose

Renal hyperfiltration (RHF) is a prevalent phenomenon in critically ill patients characterized by augmented renal clearance (ARC) and increased of elimination of renally eliminated medications. Multiple risk factors had been described and potential mechanisms may contribute to the occurrence of this condition. RHF and ARC are associated with the risk of suboptimal exposure to antibiotics increasing the risk of treatment failure and unfavorable patient outcomes. The current review discusses the available evidence related to the RHF phenomenon, including definition, epidemiology, risk factors, pathophysiology, pharmacokinetic variability, and considerations for optimizing the dosage of antibiotics in critically ill patients.

Augmented renal clearance in the ICU: estimation, incidence, risk factors and consequences-a retrospective observational study

Background

Augmented renal clearance (ARC) remains poorly evaluated in ICU. The objective of this study is to provide a full description of ARC in ICU including prevalence, evolution profile, risk factors and outcomes.

Methods

This was a retrospective, single-center, observational study. All the patients older than 18 years admitted for the first time in Medical ICU, Bichat, University Hospital, APHP, France, between January 1, 2017, and November 31, 2020 and included into the Outcomerea database with an ICU length of stay longer than 72 h were included. Patients with chronic kidney disease were excluded. Glomerular filtration rate was estimated each day during ICU stay using the measured creatinine renal clearance (CrCl). Augmented renal clearance (ARC) was defined as a 24 h CrCl greater than 130 ml/min/m².

Results

312 patients were included, with a median age of 62.7 years [51.4; 71.8], 106(31.9%) had chronic cardiovascular disease. The main reason for admission was acute respiratory failure (184(59%)) and 196(62.8%) patients had SARS-COV2. The median value for SAPS II score was 32[24; 42.5]; 146(44%) and 154(46.4%) patients were under vasopressors and invasive mechanical ventilation, respectively. The overall prevalence of ARC was 24.6% with a peak prevalence on Day 5 of ICU stay. The risk factors for the occurrence of ARC were young age and absence of cardiovascular comorbidities. The persistence of ARC during more than 10% of the time spent in ICU was significantly associated with a lower risk of death at Day 30.

Conclusion

ARC is a frequent phenomenon in the ICU with an increased incidence during the first week of ICU stay. Further studies are needed to assess its impact on patient prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01058-w.

Risk factors associated with augmented renal clearance in a mixed intensive care unit population: a retrospective study

BACKGROUND

Augmented renal clearance is increasingly recognized in critically ill patients. This condition may lead to suboptimal dosing of renally excreted medications.

AIM

Our primary objective was to identify demographic and clinical factors associated with augmented renal clearance in a mixed critically ill population.

METHOD

This retrospective single center observational cohort study evaluated patients admitted in a mixed adult intensive care unit for augmented renal clearance, defined as a creatinine clearance of ≥ 130 ml/min/1.73m²_, through weekly 24-h urine collection. Variables associated with augmented renal clearance were identified using univariate analysis, then served as covariates in a backward stepwise logistic regression. Goodness-of-fit of the model was assessed and receiver operating characteristic curve was generated.

RESULTS

Augmented renal clearance was observed in 25.3% of the study cohort (n = 324). Age below 50 years (adjusted odds ratio 7.32; 95% CI 4.03-13.29, p < 0.001), lower serum creatinine at intensive care admission (adjusted odds ratio 0.97; 95% CI 0.96-0.99, p < 0.001) and trauma admission (adjusted odds ratio 2.26; 95% CI 1.12-4.54, p = 0.022) were identified as independent risk factors. Our model showed acceptable discrimination in predicting augmented renal clearance (Area under receiver operating characteristic curve (0.810; 95% CI 0.756-0.864, p < 0.001)).

CONCLUSION

We identified age below 50 years, lower serum creatinine upon intensive care admission and trauma as independent risk factors for augmented renal clearance, consistent with the literature suggesting that patients with low serum creatinine upon admission could have a higher risk of developing augmented renal clearance.

Association between Augmented Renal Clearance and Inadequate Vancomycin Pharmacokinetic/Pharmacodynamic Targets in Chinese Adult Patients: A Prospective Observational Study

This study aimed to examine the risk factors of augmented renal clearance (ARC) and the association between ARC and vancomycin pharmacokinetic/pharmacodynamic (PK/PD) indices in Chinese adult patients. A prospective, observational, multicenter study was conducted, and 414 adult patients undergoing vancomycin therapeutic drug monitoring (TDM) were enrolled. Clinical and PK/PD data were compared between ARC and non-ARC groups. Independent risk factors were examined using a multivariate logistic regression analysis. The ARC and augmented renal clearance in trauma intensive care (ARCTIC) scoring systems were evaluated. Eighty-eight of the enrolled patients (88/414, 21.3%) had ARC before vancomycin therapy. Patients with ARC were more likely to have subtherapeutic vancomycin PK/PD indices, including trough concentration (p = 0.003) and 24 h area under the concentration−time curve (AUC24) to minimal inhibitory concentration (MIC) ratio (p < 0.001). Male sex (OR = 2.588), age < 50 years (OR = 2.713), overweight (OR = 2.072), receiving mechanical ventilation (OR = 1.785), enteral nutrition (OR = 2.317), neutrophil percentage (OR = 0.975), and cardiovascular diseases (OR = 0.281) were significantly associated with ARC. In conclusion, ARC is associated with subtherapeutic vancomycin trough concentration and AUC24/MIC; therefore, higher than routine doses may be needed. Risk factors and ARC risk scoring systems are valuable for early identification.

Validation of the Augmented Renal Clearance in Trauma Intensive Care scoring system for augmented renal clearance prediction in a trauma subgroup of a mixed ICU population

WHAT IS KNOWN AND OBJECTIVE

Augmented renal clearance is prevalent in trauma patients and leads to subtherapeutic levels of renally eliminated medications with potentially unfavourable clinical outcomes. The Augmented Renal Clearance of Trauma in Intensive Care (ARCTIC) score has been developed to predict augmented renal clearance in critically ill trauma patients. Our primary objective was to validate this score among the trauma subgroup of a mixed intensive care patient cohort.

METHODS

This single-centre, retrospective, observational cohort study assessed augmented renal clearance using a timed 24-h urine collection performed weekly. ARC was defined as a measured creatinine clearance of ≥130 ml/min/1.73 m² . ARCTIC score performance was evaluated through a receiver operator characteristic curves and analysis of sensitivities and specificities for the trauma subgroup, the medical/surgical subgroup and the pooled cohort.

RESULTS AND DISCUSSION

Augmented renal clearance was observed in 33.9% (n = 58) of trauma patients (n = 171) and 15.7% (n = 24) of medical/surgical patients (n = 153). Examination of different cutoffs for the ARCTIC score in our trauma population confirmed that the optimal cutoff score was ≥6. Comparison between ROC curves for ARCTIC score and for regression model based upon our data in trauma patients indicated validation of the score in this subgroup. Comparison of sensitivities and specificities for ARCTIC score between trauma (93.1% and 41.6%, respectively) and medical/surgical subjects (87.5% and 49.6%, respectively) showed no clinical nor statistical difference, suggesting validation for the medical/surgical subgroup as well.

WHAT IS NEW AND CONCLUSION

In our mixed ICU population, the ARCTIC score was validated in the trauma subgroup. We also found that the score performed well in the medical/surgical population. Future studies should assess the performance of the ARCTIC score prospectively.

Optimization of levetiracetam dosing regimen in critically ill patients with augmented renal clearance: a Monte Carlo simulation study

Background

Levetiracetam pharmacokinetics is extensively altered in critically ill patients with augmented renal clearance (ARC). Consequently, the dosage regimens commonly used in clinical practice may not be sufficient to achieve target plasma concentrations. The aim of this study is to propose alternative dosage regimens able to achieve target concentrations in this population. Furthermore, the feasibility of the proposed dosing regimens will be discussed from a clinical point of view.

Methods

Different dosage regimens for levetiracetam were evaluated in critically ill patients with ARC. Monte Carlo simulations were conducted with extended or continuous infusions and/or high drug doses using a previously developed population pharmacokinetic model. To assess the clinical feasibility of the proposed dosages, we carried out a literature search to evaluate the information on toxicity and efficacy of continuous administration or high doses, as well as the post-dilution stability of levetiracetam.

Results

According to the simulations, target concentrations in patients with CrCl of 160 or 200 mL/min can be achieved with the 3000 mg daily dose by prolonging the infusion time of levetiracetam. For patients with CrCl of 240 mL/min, it would be necessary to administer doses higher than the maximum recommended. Available evidence suggests that levetiracetam administration in continuous infusion or at higher doses than those approved seems to be safe. It would be desirable to re-examinate the current recommendations about drug stability and to achieve a consensus in this issue.

Conclusions

Conventional dosage regimens of levetiracetam (500–1500 mg twice daily in a short infusion) do not allow obtaining drug plasma concentrations among the defined target in critically ill patients with ARC. Therefore, new dosing guidelines with specific recommendations for patients in this subpopulation are needed. This study proposes new dosages for levetiracetam, including extended (4 or 6 h) infusions, continuous infusions or the administration of doses higher than the recommended in the summary of product characteristics (> 3000 mg). These new dosage recommendations take into account biopharmaceutical and pharmacokinetic aspects and meet feasibility criteria, which allow them to be transferred to the clinical environment with safety and efficacy. Nevertheless, further clinical studies are needed to confirm these results.

Augmented Renal Clearance in Severe Infections-An Important Consideration in Vancomycin Dosing: A Narrative Review

Vancomycin is a hydrophilic antibiotic widely used in severe infections, including bacteremia and central nervous system (CNS) infections caused by Gram-positive bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), coagulase-negative staphylococci and enterococci. Appropriate antimicrobial dosage regimens can help achieve the target exposure and improve clinical outcomes. However, vancomycin exposure in serum and cerebrospinal fluid (CSF) is challenging to predict due to rapidly changing pathophysiological processes and patient-specific factors. Vancomycin concentrations may be decreased for peripheral infections due to augmented renal clearance (ARC) and increased distribution caused by systemic inflammatory response syndrome (SIRS), increased capillary permeability, and aggressive fluid resuscitation. Additionally, few studies on vancomycin’s pharmacokinetics (PK) in CSF for CNS infections. The relationship between exposure and clinical response is unclear, challenging for adequate antimicrobial therapy. Accurate prediction of vancomycin pharmacokinetics/pharmacodynamics (PK/PD) in patients with high interindividual variation is critical to increase the likelihood of achieving therapeutic targets. In this review, we describe the interaction between ARC and vancomycin PK/PD, patient-specific factors that influence the achievement of target exposure, and recent advances in optimizing vancomycin dosing schedules for severe infective patients with ARC.

Prevalence and Risk Factors of Augmented Renal Clearance: A Systematic Review and Meta-Analysis

Kidney function assessment in the critically ill overlooks the possibility for hyperfunctioning kidneys, known as augmented renal clearance (ARC), which could contribute to therapeutic failures in the intensive care unit (ICU). The aim of this research is to conduct a systematic review and meta-analysis of prevalence and risk factors of ARC in the critically ill. MEDLINE, Embase, Cochrane Library, CINAHL, Scopus, ProQuest Dissertations and Theses Global databases were searched on 27 October 2020. We included studies conducted in critically ill adults who reported the prevalence and/or risk factors of ARC. We evaluated study quality using the Joanna Briggs Institute appraisal tool. Case reports, reviews, editorials and commentaries were excluded. We generated a random-effects meta-analytic model using the inverse variance method and visualized the pooled estimates using forest plots. Seventy studies were included. The pooled prevalence (95% CI) was 39% (34.9–43.3). Prevalence for neuro, trauma, mixed and sepsis ICUs were 74 (55–87), 58 (48–67), 36 (31–41) and 33 (21–48), respectively. Age, male sex and trauma were associated with ARC with pooled OR (95% CI) of 0.95 (0.93–0.96), 2.36 (1.28–4.36), 2.60 (1.21–5.58), respectively. Limitations included variations in ARC definition, inclusion and exclusion criteria and studies design. In conclusion, ARC is prevalent in critically ill patients, especially those in the neurocritical care and trauma ICU population. Young age, male sex and trauma are risk factors for ARC in those with apparently normal renal function. Further research on optimal dosing of drugs in the setting of ARC is warranted. (Prospero registration: CRD42021246417).

Population Pharmacokinetics of Vancomycin in Adult Patients with Long Bones’ Fractures

Vancomycin is a tricyclic glycopeptide antibiotic, mostly used in the treatment of severe staphylococcal and enterococcal infections, especially in orthopedic surgery.

The purpose of this analysis was to develop a population pharmacokinetic (PPK) model of vancomycine in hospitalized patients with bone fractures and identify important factors which influence its clearance (CL).

A total of ninety-nine measurements of vancomycin serum concentrations were used in our population modeling. A two-compartment model was applied to describe the pharmacokinetics of vancomycin using subroutines ADVAN3 and TRANS4.

The study population included patients of both sexes, with the mean age of 62.12±14.69 years and body weight of 80.32±12.44kg. Vancomycin was administered as intravenous infusion with average daily dose of 1772.73±521.34mg. Out of twenty different factors evaluated in the study (including demographic, clinical and laboratory data), only daily dose of vancomycin (DD) and co-medication with piperacillin/tazobactam (PT) showed significant effect on clearance of vancomycin. The final model was described by the following equation: CL (l/h) = 0.03 + 0.000468 x DD + 0.675 x PT. Bootstrapping was used for validation of the final model.

In conclusion, the main causes of variability in the clearance of vancomycin among adult patients with bone fractures are daily dose of vancomycin and co-medication with piperacillin/tazobactam.

Augmented Renal Clearance: What Have We Known and What Will We Do?

Augmented renal clearance (ARC) is a phenomenon of increased renal function in patients with risk factors. Sub-therapeutic drug concentrations and antibacterial exposure in ARC patients are the main reasons for clinical treatment failure. Decades of increased research have focused on these phenomena, but there are still some existing disputes and unresolved issues. This article reviews information on some important aspects of what we have known and provides suggestion on what we will do regarding ARC. In this article, we review the current research progress and its limitations, including clinical identification, special patients, risk factors, metabolism, animal models and clinical treatments, and provide some promising directions for further research in this area.

Population Pharmacokinetics of Levetiracetam and Dosing Evaluation in Critically Ill Patients with Normal or Augmented Renal Function

Levetiracetam is a broad-spectrum antiepileptic drug commonly used in intensive care units (ICUs). The objective of this study is to evaluate the adequacy of levetiracetam dosing in patients with normal or augmented renal clearance (ARC) admitted to the ICU by population modelling and simulation. A multicentre prospective study including twenty-seven critically ill patients with urinary creatinine clearance (CrCl) > 50 mL/min and treated with levetiracetam was developed. Levetiracetam plasma concentrations were best described by a two-compartment model. The parameter estimates and relative standard errors (%) were clearance (CL) 3.5 L/h (9%), central volume of distribution (V1) 20.7 L (18%), intercompartmental clearance 31.9 L/h (22%), and peripheral volume of distribution 33.5 L (13%). Interindividual variability estimates were, for the CL, 32.7% (21%) and, for V1, 56.1% (29%). The CrCl showed significant influence over CL. Simulations showed that the administration of at least 500 mg every 8 h or 1000 mg every 12 h are needed in patients with normal renal function. Higher doses (1500 or 2000 mg, every 8 h) are needed in patients with ARC. Critically ill patients with normal or ARC treated with levetiracetam could be at high risk of being underdosed.

Scoping review of augmented renal clearance in critically ill pediatric patients

Augmented renal clearance (ARC), a phenomenon of enhanced elimination of renal solutes, has been described in adult critically ill patients, but little is known about the phenomenon in children. The aim of this scoping review was to gather and summarize all evidence on ARC in pediatric patients to examine its breadth and depth including prevalence, risk factors, and pharmacokinetic alterations and identify any gaps for further areas of inquiry. PubMed, Embase, and Web of Science were searched for titles, abstracts, or keywords that focused on ARC. Non-English studies, reviews, and nonhuman studies were excluded. Reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR) guidelines. Data were extracted on article type, study details, patient population, ARC definition and prevalence, methods of renal function assessment, and study results. A total of 215 citations were found with 25 citations meeting the criteria for inclusion in pediatrics (2102 total patients); the majority of studies (84%) focused on pharmacokinetics (PK) of antimicrobial agents. The median/mean age range was 1.25-12 years. There were a total of 10 different definitions of ARC. The prevalence of ARC ranged from 7.8% to 78%. The most common method for documenting creatinine clearance (CrCl) was the modified Schwartz equation (64%). Only 20% of studies reported risk factors for ARC including low serum creatinine, increasing age, febrile neutropenia, male, septic shock, and treatment with antibiotics. Glycopeptide antimicrobials were the most evaluated class (42.9%) among the 21 antimicrobial drug studies. All studies reported increased drug clearance and/or poor probability of achieving target concentrations of the agents studied. ARC showed variable prevalence in pediatric patients likely due to the lack of a standard definition and many studies not considering age-related changes in CrCl with pediatric intensive care unit (PICU) patients. ARC was shown to impact PK of antibiotics commonly administered to pediatric patients, which may necessitate changes in standard dosing regimens.

Knowledge, attitudes, and practices related to augmented renal clearance among pediatricians in China: A cross-sectional study

Our purpose was to assess pediatricians' knowledge of augmented renal clearance (ARC).We conducted cross-sectional analyses of 500 pediatricians from 16 tertiary hospitals in Anhui Province, China. Pediatricians provided demographic information and were asked questions about their knowledge of ARC, including risk factors, evaluation tools, and the impact on patient prognosis, with a focus on the attitude and practice of pediatricians related to adjusting vancomycin regimens when ARC occurs.A total of 491 valid questionnaires were finally included, only 276 pediatricians stated that they "know about ARC." Compared with the "do not know about ARC" group, the "know about ARC" group was younger (43.7 ± 8.0 vs 48.0 ± 7.9, P < .001), and their main source of ARC knowledge was from social networking platforms. A total of 193 (70%) chose at least 4 of the following factors as risk factors for children with ARC: severe trauma, sepsis, burns, major surgery, lower disease severity, and hematological malignancies. A total of 110 (40%) and 105 (38%) pediatricians chose the Schwartz formula and cystatin C, respectively, as the indicators to evaluate the renal function of ARC children. Concerning the estimated glomerular filtration rate threshold to identify ARC children, 201 (73%) pediatricians chose 130 mL/min/1.73 m2, while 55 (20%) chose "age-dependent ARC thresholds." Overall, 220 (80%) respondents indicated that ARC would impact the treatment effect of vancomycin, but 149/220 (68%) were willing to adjust the vancomycin regimen; only 22/149 (8%) considered that the dose should be increased, but no one knew how to increase. Regarding the prognosis of ARC children, all respondents chose "unclear."ARC is relatively common in critically ill children, but pediatricians do not know much about it, as most of the current knowledge is based on adult studies. Furthermore, ARC is often confused with acute kidney injury, which would lead to very serious treatment errors. Therefore, more pediatric studies about ARC are needed, and ARC should be written into official pediatric guidelines as soon as possible to provide reference for pediatricians.

Augmented renal clearance: a retrospective, cohort study of urinary creatinine clearance in critically ill patients in the United Kingdom

OBJECTIVE

Augmented renal clearance (ARC) is associated with sub-therapeutic antibiotic, anti-epileptic, and anticoagulant serum concentrations leading to adverse patient outcomes. We aimed to describe the prevalence and associated risk factors for ARC development in a large, single-centre cohort in the United Kingdom.

METHODS

We conducted a retrospective observational study of critically unwell patients admitted to intensive care between 2014 and 2016. Urinary creatinine clearance was used to determine the ARC prevalence during the first 7 days of admission. Repeated measures logistic regression was used to determine risk factors for ARC development.

RESULTS

The ARC prevalence was 47.0% (95% confidence interval [95%CI]: 44.3%-49.7%). Age, sex, Acute Physiology and Chronic Health Evaluation (APACHE) II score, and sepsis diagnosis were significantly associated with ARC. ARC was more prevalent in younger vs. older (odds ratio [OR] 0.95 [95%CI: 0.94-0.96]), male vs. female (OR 0.32 [95%CI: 0.26-0.40]) patients with lower vs. higher APACHE II scores (OR 0.94 [95%CI: 0.92-0.96]).

CONCLUSIONS

This patient group probably remains unknown to many clinicians because measuring urinary creatinine clearance is not usually indicated in this group. Clinicians should be aware of the ARC risk in this group and consider measurement of urinary creatinine clearance.

The Development of a Juvenile Porcine Augmented Renal Clearance Model Through Continuous Infusion of Lipopolysaccharides: An Exploratory Study

Augmented renal clearance (ARC) as observed in the critically ill (pediatric) population can have a major impact on the pharmacokinetics and posology of renally excreted drugs. Although sepsis has been described as a major trigger in the development of ARC in human critically ill patients, mechanistic insights on ARC are currently lacking. An appropriate ARC animal model could contribute to reveal these underlying mechanisms. In this exploratory study, a state of ARC was induced in 8-week-old piglets. Conscious piglets were continuously infused over 36 h with lipopolysaccharides (LPS) from Escherichia coli (O111:B4) to induce sepsis and subsequently trigger ARC. To study the dose-dependent effect of LPS on the renal function, three different doses (0.75, 2.0, 5.0 μg/kg/h) were administered (two ♂ piglets/dose, one sham piglet), in combination with fluid administration (0.9% NaCl) at 6 ml/kg/h. Single boluses of renal markers, i.e., creatinine [40 mg/kg body weight (BW)], iohexol (64.7 mg/kg BW), and para-aminohippuric acid (PAH, 10 mg/kg BW) were administered intravenously to evaluate the effect of LPS on the renal function. Clinical parameters were monitored periodically. Blood sampling was performed to determine the effect on hematology, neutrophil gelatinase-associated lipocalin, and prostaglandin E₂ plasma levels. All piglets that were continuously infused with LPS displayed an elevated body temperature, heart rhythm, and respiratory rate ~1-3 h after start of the infusion. After infusion, considerably higher total body clearances of iohexol, creatinine, and PAH were observed, independent of the administration of LPS and/or its dose. Since also the sham piglet, receiving no LPS, demonstrated a comparable increase in renal function, the contribution of fluid administration to the development of ARC should be further evaluated.

Unraveling the Contribution of Fluid Therapy to the Development of Augmented Renal Clearance in a Piglet Model

Augmented renal clearance (ARC) observed in the critically ill pediatric population has received an increased attention over the last years due to its major impact on the disposition and pharmacokinetics of mainly renally excreted drugs. Apart from an important inflammatory trigger, fluid administration has been suggested to contribute to the development of ARC. Therefore, the primary objective of this study was to evaluate the effect of continuous intravenous fluid administration on renal function using a conventional piglet animal model and to quantify the impact of fluid administration on the pharmacokinetics of renally excreted drugs. At baseline, twenty-four piglets (12 treatment/12 control; 7 weeks old, all ♂) received the marker drugs iohexol (64.7 mg/kg body weight (BW)) and para-aminohippuric acid (10 mg/kg BW) to quantify glomerular filtration rate and effective renal plasma flow, respectively. In addition, the hydrophilic antibiotic amikacin (7.5 mg/kg BW) was administered. Following this baseline measurement, the treatment group received fluid therapy as a constant rate infusion of 0.9% saline at 6 mL/kg/h over 36 h. After 24 h of fluid administration, the marker drugs and amikacin were administered again. When comparing both groups, a significant effect of fluid administration on the total body clearances of iohexol (p = 0.032) and amikacin (p = 0.0014) was observed. Clearances of iohexol and amikacin increased with on average 15 and 14%, although large interindividual variability was observed. This led to decreased systemic exposure to amikacin, which was manifested as decrease in area under the plasma concentration-time curve from time 0 h to infinity from 34,807 to 30,804 ng.h/mL. These results suggest that fluid therapy is a key factor involved in the development of ARC and should be taken into account when administering mainly renally excreted drugs. However, further research is necessary to confirm these results in children.

An individualized administration model of vancomycin in elderly patients with sepsis and factors influencing augmented renal clearance

WHAT IS KNOWN AND OBJECTIVE

Vancomycin efficacy is dependent on appropriate dosing, which should aim to achieve a target serum trough level. The purpose of this study was to determine the variables that predicted vancomycin serum trough concentrations in elderly patients with sepsis.

METHODS

This retrospective cohort study, which was conducted in the medical ICU of a university-affiliated teaching hospital in China, included 87 medical patients with sepsis who were enrolled from January 2014 to December 2017.

RESULTS AND DISCUSSION

All the patients were at least 60 years old (mean age = 74.8 ± 8.2 years), and 51.7% (n = 45) of them were male. The most common primary site of infection was the lungs (67.8%), followed by the abdomen (12.6%). Patients with septic shock accounted for 21.8% (n = 19) of the cases. The proportion of patients with vancomycin serum trough concentrations reaching target concentrations (≥15 mg/L) was 47.1% (41 cases). Multivariate linear regression showed that the creatinine clearance rate (CCR) and the daily dosage of vancomycin were independent predictors of vancomycin serum trough concentrations (both p's < 0.05), and the model for predicting vancomycin trough concentrations should be: serum trough concentration (mg/L) = 15.942 - 0.101 × CCR (mL/min) + 0.347 × vancomycin daily doses (mg/kg/d). Augmented renal clearance (ARC) was present in 13 patients (14.9%), and logistic regression revealed body mass index (OR = 1.420, p = .002) and serum creatinine level (OR = 0.883, p = .002) were independent predictors of ARC.

WHAT IS NEW AND CONCLUSION

The CCR and daily dosage of vancomycin were significantly correlated with vancomycin serum trough concentrations in elderly patients with sepsis, and the individualized administration model should be verified through further clinical trials. BMI and serum creatinine level were identified to be independent predictors of ARC in elderly patients.

Optimization of Vancomycin Dosing Regimen in Cancer Patients using Pharmacokinetic/Pharmacodynamic Modeling

BACKGROUND

Gram-positive bacterial infections are considered one of the major causes of mortality and morbidity in patients with cancer. Hence, the challenge lies in regulating the pervasive use of vancomycin in the management of infections facing such patients due to the anomalous vancomycin pharmacokinetics (PKs) and pharmacodynamics (PDs). Inappropriate vancomycin exposure is associated with toxicity, pathogen resistance, and therapeutic failure.

OBJECTIVE

The aim of this study was to estimate vancomycin PK in patients with cancer and without cancer. The standard dosage regimens of vancomycin were then evaluated using data from PK modeling.

METHODS

In this observational PK study, the data were extracted from a matched patient cohort of those with cancer and those without cancer. Pharmacokinetic analysis was performed using Monolix version 4.4, and the PK parameters were compared in both groups (cancer vs noncancer). The standard and suggested vancomycin dosing regimens were evaluated using PK/PD modeling and Monte Carlo Simulations.

RESULTS

In total, 448 blood samples were analyzed from 147 patients enrolled in this study, of which 73 patients had cancer and 74 patients were noncancer patients. In general, no significant differences were observed between the two groups (cancer vs noncancer) in all characteristics except for the vancomycin levels, which were significantly lower in patients with cancer (p = 0.00104). This analysis showed that patients with cancer showed a significantly higher vancomycin clearance than noncancer patients (p = 0.002), whereas the volume of distribution (V) was found to be similar in both groups (p = 0.83).This resulted in most of the patients failing to achieve the target area under the curve from zero to 24 hours (AUC_0-2 ) to the minimum inhibitory concentration. These data showed that a higher maintenance dose of vancomycin is required to achieve the PD target.

CONCLUSIONS

The findings of this study showed that the patients with cancer have lower levels of vancomycin due to higher clearance than noncancer patients. Thus, higher doses than the standard vancomycin doses may be needed to treat invasive Methicillin-resistant Staphylococcus aureus infections in patients with cancer.

Factors increasing the risk of inappropriate vancomycin therapy in ICU patients: A prospective observational study

BACKGROUND

Vancomycin trough levels are frequently subtherapeutic in intensive care unit (ICU) patients. The aim of this study was to identify patients at risk of therapeutic failure defined as vancomycin area-under-the-curve_0-24 /minimum inhibitory concentration (AUC_0-24 /MIC) <400, and to examine possible effects of different MICs, the variability in renal clearance and continuous renal replacement therapy (CRRT), and the relevance of vancomycin therapy.

METHODS

A prospective observational study of ICU patients ≥ 18 years at initiation of vancomycin therapy was conducted from May 2013 to October 2015. The patients were divided into four groups according to renal function and CRRT-mode as follows: normal- or augmented renal clearance and continuous venovenous hemodialysis or -hemofiltration. Vancomycin peak and trough levels were measured at 24, 48, and 72 hours after therapy initiation. Relevance of vancomycin therapy was retrospectively evaluated based on microbiological results.

RESULTS

Eighty-three patients were included, median age 54.5 years, 74.5% male, SAPS II score 46, and 90 day mortality 28%. Vancomycin therapy was initiated on ICU-day 8 (IQR, 5-12), with a median treatment time of 7.5 (IQR, 5-12) days. AUC_0-24 /MIC > 400 was reached in 81% and 8% with MIC = 1 and 2 mg/L respectively. The CRRT groups had higher AUC_0-24 /MIC-ratios than the non-CRRT groups (P < .001). Augmented renal clearance increased the risk of AUC_0-24 /MIC < 400, independent of MIC-value. Initiation of vancomycin therapy was retrospectively considered relevant in 28 patients (34%).

CONCLUSION

A MIC-value >1 mg/L and augmented renal clearance, were factors increasing the risk of therapeutic failure. Vancomycin treatments could have been omitted or shortened in most of these patients.

Vancomycin dosing in critically ill trauma patients: The VANCTIC Study

BACKGROUND

Current guidelines from the Infectious Diseases Society of America and the American Society of Health-System Pharmacists recommend vancomycin troughs of 15 mg/L to 20 mg/L for serious methicillin-resistant Staphylococcus aureus infections. The pharmacokinetics of vancomycin are altered in critically ill patients, leading to inadequate serum levels. Rates of initial therapeutic vancomycin troughs have ranged from 17.6% to 33% using intermittent infusions (i.e., 15-20 mg/L) and approximately 60% using continuous infusions (i.e., 15-25 mg/L) in critically ill trauma patients (1-4). We hypothesized that our dosing protocol would achieve higher rates of initial therapeutic troughs compared with previously published reports due to more aggressive loading doses than those seen in previously published reports.

METHODS

This was a retrospective study of all critically ill trauma patients admitted to a Level I trauma intensive care unit over a 39-month period who had a suspected serious infection, who were treated with empiric vancomycin per the "pharmacy to dose" protocol, and who had an appropriately drawn steady state trough level. The primary outcome was the rate of initial therapeutic troughs, which was defined as 14.5 mg/L to 20.5 mg/L.

RESULTS

One hundred ninety-seven patients were screened. Seventy patients met inclusion criteria. The study cohort had a median age of 47.5 years and a median Injury Severity Score of 28. Augmented renal clearances were observed, with a median creatinine clearance of 159.1 mL/min and a median Augmented Renal Clearance in Trauma Intensive Care (ARCTIC) score of 7. The median vancomycin loading dose was 24.6 mg/kg with an initial maintenance dose of 17.71 mg/kg. An every eight hour dosing interval was initiated on 47.14% of the patients, and 45.71% of the patients were initially started on an every 12 hour dosing interval. Only 15.71% of the study patients achieved an initial therapeutic trough; 42.86% were less than 10 mg/L, and 8.57% were greater than 20.5 mg/L. Acute kidney injury occurred in 10% based on the Infectious Diseases Society of America/American Society of Health-System Pharmacists vancomycin guidelines and in 11.4% based on the Acute Kidney Injury Network criteria.

CONCLUSION

Our incidence of initial therapeutic troughs was slightly below previously reported studies. Based on our results, which are consistent with previous literature, it would appear that our guideline-adherent protocol of intermittent vancomycin is insufficient to achieve troughs of 15 mg/L to 20 mg/L.

LEVEL OF EVIDENCE

Therapeutic, level III.

Enhanced Renal Clearance in Patients With Hemorrhagic Stroke

OBJECTIVES

To evaluate enhanced renal clearance over time in patients with aneurysmal subarachnoid hemorrhage or intracerebral hemorrhage via measured creatinine clearance and to compare measured creatinine clearance to creatinine clearance calculated by the Cockcroft-Gault equation and estimated glomerular filtration rate calculated by the Modification of Diet in Renal Diseases equation.

DESIGN

Prospective, observational study.

SETTING

Neurosciences ICU in a tertiary care academic medical center.

PATIENTS

Study participants had an admission diagnosis of aneurysmal subarachnoid hemorrhage or intracerebral hemorrhage, an expected neurosciences ICU length of stay greater than 48 hours, no evidence of renal dysfunction (admission serum creatinine < 1.5 mg/dL), and no history of chronic kidney disease.

INTERVENTIONS

Eight-hour urine collections to measure creatinine clearance were collected daily as the primary method of measuring renal function. Creatinine clearance was also calculated using the Cockcroft-Gault equation and estimated glomerular filtration rate was calculated using the Modification of Diet in Renal Disease equation. Enhanced renal clearance was defined as a measured creatinine clearance greater than the calculated creatinine clearance via Cockcroft-Gault and estimated glomerular filtration rate via Modification of Diet in Renal Disease. Augmented renal clearance was defined by a measured creatinine clearance greater than or equal to 130 mL/min/1.73 m. Relevant demographic, clinical, and outcome data were recorded.

MEASUREMENTS AND MAIN RESULTS

Fifty aneurysmal subarachnoid hemorrhage patients and 30 intracerebral hemorrhage patients were enrolled, contributing 590 individual measurements. Patients with aneurysmal subarachnoid hemorrhage had a higher mean measured creatinine clearance compared with the mean calculated creatinine clearance based on the Cockcroft-Gault equation (147.9 ± 50.2 vs 109.1 ± 32.7 mL/min/1.73 m; p < 0.0001) and higher mean measured creatinine clearance compared with the mean calculated estimated glomerular filtration rate based on the Modification of Diet in Renal Disease equation (147.9 ± 50.2 vs 126.0 ± 41.9 mL/min/1.73 m; p = 0.04). Ninety-four percent of participants with aneurysmal subarachnoid hemorrhage experienced augmented renal clearance on at least 1 day. In patients with intracerebral hemorrhage, there was a higher mean measured creatinine clearance over the study period compared with the mean calculated creatinine clearance (119.5 ± 57.2 vs 77.8 ± 27.6 mL/min/1.73 m; p < 0.0001) and higher mean measured creatinine clearance compared with the mean calculated estimated glomerular filtration rate based on the Modification of Diet in Renal Disease equation (119.5 ± 57.2 vs 93.0.0 ± 32.8 mL/min/1.73 m; p = 0.02). Fifty percent of participants with intracerebral hemorrhage experienced augmented renal clearance on at least 1 day.

CONCLUSIONS

A substantial group of patients with aneurysmal subarachnoid hemorrhage or intracerebral hemorrhage experienced enhanced renal clearance, which may be otherwise unknown to clinicians. Enhanced renal clearance may lead to increased renal solute elimination over what is expected, resulting in subtherapeutic renally eliminated drug concentrations. This may result in underexposure to critical medications, leading to treatment failure and other medical complications.

Differences in Vancomycin Clearance between Trauma and Medical Intensive Care Unit Patients

Background

To identify the differences in the vancomycin pharmacokinetics between multiple trauma patients and medically ill patients in the intensive care unit (ICU) stratified by the use of continuous renal replacement therapy (CRRT), and the factors affecting vancomycin clearance (CL_van).

Materials and Methods

All the included patients received at least three consecutive doses of vancomycin, then, therapeutic drug monitoring was conducted. Patients' serum vancomycin trough levels and other clinical variables were identified retrospectively. The vancomycin pharmacokinetics and associated factors were compared and analyzed between trauma ICU (TICU) and medical ICU (MICU) patients.

Results

In the non-dialyzed group, the CL_van was higher among the TICU patients than the MICU patients. However, in the continuous renal replacement therapy group, there was no significant difference in the CL_van between the multiple trauma and medically ill patients. The only factor associated with CL_van in the non-dialyzed group was creatinine clearance; none of the factors was associated with CL_van in the CRRT group.

Conclusion

In the case of non-dialyzed patients in the TICU, vancomycin dosages must be adjusted, depending on the patient's actual body weight changes. In the case of patients undergoing CRRT in both ICUs, vancomycin can be infused with fixed doses regardless of the patients' characteristics.

Augmented renal clearance in pediatric intensive care: are we undertreating our sickest patients?

Many critically ill patients display a supraphysiological renal function with enhanced renal perfusion and glomerular hyperfiltration. This phenomenon described as augmented renal clearance (ARC) may result in enhanced drug elimination through renal excretion mechanisms. Augmented renal clearance seems to be triggered by systemic inflammation and therapeutic interventions in intensive care. There is growing evidence that ARC is not restricted to the adult intensive care population, but is also prevalent in critically ill children. Augmented renal clearance is often overlooked due to the lack of reliable methods to assess renal function in critically ill children. Standard equations to calculate glomerular filtration rate (GFR) are developed for patients who have a steady-state creatinine production and a stable renal function. Those formulas are not reliable in critically ill patients with acutely changing GFR and tend to underestimate true GFR in patients with ARC. Tools for real-time, continuous, and non-invasive measurement of fluctuating GFR are most needed to identify changes in kidney function during critical illness and therapeutic interventions. Such devices are currently being validated and hold a strong potential to become the standard of practice. In the meantime, urinary creatinine clearance is considered the most reliable method to detect ARC in critically ill patients. Augmented renal clearance is clearly associated with subtherapeutic antimicrobial concentrations and subsequent therapeutic failure. This warrants the need for adjusted dosing regimens to optimize pharmacokinetic and pharmacodynamic target attainment. This review aims to summarize current knowledge on ARC in critically ill children, to give insight into its possible pathophysiological mechanism, to evaluate screening methods for ARC in the pediatric intensive care population, and to illustrate the effect of ARC on drug exposure, therapeutic efficacy, and clinical outcome.

Enhanced renal clearance and impact on vancomycin pharmacokinetic parameters in patients with hemorrhagic stroke

BACKGROUND

The majority of patients with hemorrhagic stroke experience enhanced renal clearance or augmented renal clearance (ARC). The purpose of this study was to determine the impact of enhanced renal clearance or ARC on vancomycin pharmacokinetic (PK) parameters.

METHODS

This was a post hoc analysis of a prospective study of adult patients with aneurysmal subarachnoid hemorrhage (aSAH) or intracerebral hemorrhage (ICH) admitted to the neurosciences intensive care unit who received vancomycin. Creatinine clearance (CrCl) was measured and also estimated using the Cockcroft-Gault equation. Predicted PK parameters were compared with calculated PK parameters using serum peak and trough concentrations.

RESULTS

Seventeen hemorrhagic stroke patients met inclusion criteria. All patients experienced enhanced renal clearance on the day that the vancomycin concentrations were obtained, and 12 patients (71%) experienced ARC. The mean calculated elimination rate constant was significantly higher than the predicted value (0.141 ± 0.02 vs. 0.087 ± 0.01 h-1; p = 0.004) and the mean calculated half-life was significantly lower than the predicted half-life (6.5 ± 0.9 vs. 8.7 ± 0.6 h; p = 0.03).

CONCLUSIONS

Patients with hemorrhagic stroke and enhanced renal clearance displayed PK alterations favoring an increased elimination of vancomycin than expected. This may result in underexposure to vancomycin, leading to treatment failure.

[Effect of augmented renal clearance on plasma concentration of vancomycin and treatment outcome in children with methicillin-resistant Staphylococcus aureus infection]

OBJECTIVE

To investigate the effect of augmented renal clearance (ARC) on plasma concentration of vancomycin, bacteriological outcome, and clinical outcome in children with methicillin-resistant Staphylococcus aureus (MRSA) infection treated by vancomycin.

METHODS

A retrospective analysis was performed for the clinical data of 60 critically ill children who were treated with vancomycin due to MRSA infection from January 2013 to July 2017 and underwent plasma concentration monitoring. According to estimated glomerular filtration rate, these children were divided into an ARC group with 19 children and a normal renal function group with 41 children. The two groups were compared in terms of the use of vancomycin, plasma concentration of vancomycin, and treatment outcome.

RESULTS

The children in the ARC group had an age of 1-12 years, and the ARC group had significantly higher body weight and body surface area than the normal renal function group (P<0.05). Compared with the normal renal function group, the ARC group had a significantly lower initial trough concentration of vancomycin and a significantly lower proportion of children who achieved the effective trough concentration of vancomycin (10-20 mg/L) (P<0.05). There were no significant differences in bacteriological outcome and clinical outcome between the two groups (P>0.05), but the ARC group had significantly longer length of stay in the pediatric intensive care unit (PICU) and length of hospital stay than the normal renal function group (P<0.05).

CONCLUSIONS

ARC can significantly reduce the trough concentration of vancomycin and prolong the length of PICU stay and the length of hospital stay in children with MRSA infection. Idividualized medication should be administered to children with ARC.

Utilization of Augmented Renal Clearance in Trauma Intensive Care Scoring System to Improve Vancomycin Dosing in Trauma Patients at Risk for Augmented Renal Clearance

Background: The Augmented Renal Clearance in Trauma Intensive Care (ARCTIC) scoring system is a validated system to predict augmented renal clearance in trauma patients. This study examined the ability of the ARCTIC score to identify patients at risk for subtherapeutic vancomycin trough concentrations relative to estimated creatinine clearance (eCrCl) alone. Methods: Trauma patients admitted to the intensive care unit from September 2012 to December 2017 who received vancomycin and had a vancomycin trough concentration recorded were included. Patients were excluded if their serum creatinine concentration was >1.3 mg/dL, if they had received vancomycin doses <30 mg/kg per day, an improperly timed trough concentration measurement, or renal replacement therapy. The primary endpoint was an initial subtherapeutic vancomycin trough concentration (<10 mg/L). Classification and regression tree (CART) analysis was used to identify thresholds for the ARCTIC score and other continuous data where subtherapeutic troughs were more common. A step-wise logistic regression analysis was performed to control for confounders for subtherapeutic troughs whereby inclusion of ARCTIC was modeled sequentially after eCrCl. Results: A total of 119 patients with a mean age of 42 ± 17 years and eCrCl 142 ± 39 mL/min met the inclusion criteria. The mean daily vancomycin dose was 44 ± 9 mg/kg, and the incidence of subtherapeutic trough concentration was 46%. The CART analysis identified two variables creating three groups where subtherapeutic trough concentrations differed: eCrCl >105 mL/min and ARCTIC score ≥7, eCrCl >105 mL/min and ARCTIC score <7, and eCrCl ≤105 mL/min. The base logistic regression model identified eCrCl >105 mL/min and pelvic fracture as risk factors for subtherapeutic trough values. The final model included the addition of ARCTIC score ≥7, which improved the model significantly (p = 0.009). Predictors of subtherapeutic trough concentrations were (odds ratio [95% confidence interval]): eCrCl >105 mL/min (6.5 [1.66-25.07]), ARCTIC score ≥7 (3.26 [1.31-8.09]), and pelvic fracture (4.36 [1.27-14.93]). Conclusion: The ARCTIC score is useful when applied in conjunction with eCrCl. Patients with a eCrCl >105 mL/min and an ARCTIC score ≥7 may require a more aggressive dosing strategy.

Augmented renal clearance: a common condition in critically ill children

BACKGROUND

Augmented renal clearance (ARC), an increase in kidney function with enhanced elimination of circulating solute, has been increasingly recognized in critically ill adults. In a pediatric intensive care setting, data are scarce. The primary objective of this study was to investigate the prevalence of ARC in critically ill children. Secondary objectives included a risk factor analysis for the development of ARC and a comparison of two methods for assessment of renal function.

METHODS

In 105 critically ill children between 1 month and 15 years of age, glomerular filtration rate (GFR) was measured by means of a daily 24-h creatinine clearance (24 h Cl_Cr) and compared to an estimated GFR using the revised Schwartz formula. Logistic regression analysis was used to identify risk factors for ARC.

RESULTS

Overall, 67% of patients expressed ARC and the proportion of ARC patients decreased during consecutive days. ARC patients had a median Cl_Cr of 142.2 ml/min/1.73m² (IQR 47.1). Male gender and antibiotic treatment were independently associated with the occurrence of ARC. The revised Schwartz formula seems less appropriate for ARC detection.

CONCLUSIONS

A large proportion of critically ill children develop ARC during their stay at the intensive care unit. Clinicians should be cautious when using Schwartz formula to detect ARC. Our findings require confirmation from large study cohorts and investigation of the relationship with clinical outcome.

The effect of neutropenia on the clinical pharmacokinetics of vancomycin in adults

AIM

There is accumulating evidence that neutropenic patients require higher dosages of vancomycin. To prevent sub-therapeutic drug exposure, it is of utmost importance to obtain adequate exposure from the first dose onwards. We aimed to quantify the effect of neutropenia on the pharmacokinetics of vancomycin.

METHODS

Data were extracted from a matched patient cohort of patients known with (1) hematological disease, (2) solid malignancy, and (3) patients not known with cancer. Pharmacokinetic analysis was performed using non-linear mixed effects modeling with neutropenia investigated as a binary covariate on clearance and volume of distribution of vancomycin.

RESULTS

A total of 116 patients were included (39 hematologic patients, 39 solid tumor patients, and 38 patients not known with cancer). In total, 742 paired time-concentration observations were available for the pharmacokinetic analysis. Presence of neutropenia showed to significantly (p = 0.00157) increase the clearance of vancomycin by 27.7% (95% CI 10.2-46.2%), whereas it did not impact the volume of distribution (p = 0.704).

CONCLUSIONS

This study shows that vancomycin clearance is increased in patients with neutropenia by 27.7%. Therefore, the vancomycin maintenance dose should be pragmatically increased by 25% in neutropenic patients at the start of treatment. Since the volume of distribution appeared unaffected, no adjustment in loading dose is required. These dose adjustments do not rule out the necessity of further dose individualization by means of therapeutic drug monitoring.

Prevalence and Risk Factors for Augmented Renal Clearance in a Population of Critically Ill Patients

BACKGROUND

Critically ill patients show a high, albeit variable, prevalence of augmented renal clearance (ARC). This condition has relevant consequences on the elimination of hydrophilic drugs. Knowledge of risk factors for ARC helps in the early identification of ARC. The aims of this study were evaluation of (1) risk factors for ARC and (2) the prevalence of ARC in critically ill patients over a period of 1 year.

METHODS

A retrospective cohort study was performed for all consecutive patients admitted to our intensive care unit (ICU). Augmented renal clearance was defined by a creatinine clearance ≥130 mL/min/1.73 m². "Patient with ARC" was defined as a patient with a median of creatinine clearance ≥130 mL/min/1.73 m² over the period of admission. Four variables were tested, Simplified Acute Physiology Score II (SAPS II), male gender, age, and trauma as cause for ICU admission. An analysis (patient based and clearance based) was performed with logistic regression.

RESULTS

Of 475 patients, 446 were included in this study, contributing to 454 ICU admissions and 5586 8-hour creatinine clearance (8h-CL_CR). Overall, the prevalence of patients with ARC was 24.9% (n = 113). In a subset of patients with normal serum creatinine levels, the prevalence was 43.0% (n = 104). Of the set of all 8h-CL_CR measurements, 25.4% (1418) showed ARC. In the patient-based analysis, the adjusted odds ratio was: 2.0 (confidence interval [CI]:1.1-3.7; P < .05), 0.93 (CI: 0.91-0.94; P < .01), 2.7 (CI: 1.4-5.3; P < .01), and 0.98 (CI: 0.96 -1.01; P = .15), respectively, for trauma, age, male sex, and SAPS II. In the clearance-based analysis, the adjusted odds ratio were 1.7 (CI: 1.4-1.9; P < .01), 0.94 (CI: 0.932-0.942; P < .01), and 2.9 (CI: 2.4-3.4; P < .01), respectively, for trauma, age, and male sex.

CONCLUSIONS

Trauma, young age, and male sex were independent risk factors for ARC. This condition occurs in a considerable proportion of critical care patients, which was particularly prevalent in patients without evidence of renal dysfunction.

Pharmacokinetics of Vancomycin in Patients with Different Renal Function Levels

There are many determinants of vancomycin clearance, but these have not been analyzed separately in populations with different levels of renal function, which could be why some important factors have been missed. The aim of our study was to compare the pharmacokinetic parameters and factors that may affect vancomycin pharmacokinetics in groups of patients with normal renal function and in those with chronic kidney failure. The study used a population pharmacokinetic modeling approach, based on plasma vancomycin concentrations and other data from 78 patients with chronic kidney failure and 32 patients with normal renal function. The model was developed using NONMEM software and validated by bootstrapping. The final model for patients with impaired kidney function was described by the following equation: CL (L/h) = 0.284 + 0.000596 x DD + 0.00194 x AST, and that for the patients with normal kidney function by: CL (L/h) = 0.0727 + 0.205 x FIB. If our results are confirmed by new studies on two similar populations, these factors could be considered when dosing vancomycin in patients with chronically damaged kidneys, as well as in patients with normal kidneys who frequently require high doses of vancomycin.

Validation of a Nomogram for Achieving Target Trough Concentration of Vancomycin: Accuracy in Patients With Augmented Renal Function

BACKGROUND

Adjustment of initial vancomycin (VCM) dosage has been recommended on the basis of the renal function nomogram in therapeutic drug monitoring guidelines in Japan. However, this nomogram has not been clinically validated, and few studies have focused on its usefulness in patients with risk of augmented renal function. Therefore, this study aimed to evaluate the validity of the VCM nomogram and the association between patient conditions related to augmented renal function and its accuracy.

METHODS

In this retrospective study, we screened data of 398 patients who received VCM and had estimated glomerular filtration rates ≥30 mL·min·1.73 m. Patients who met nomogram dosing criteria were categorized into a nomogram group, and the associations of age, renal function, and individual conditions such as febrile neutropenia, solid tumor, blood cancer, and brain injury with subtherapeutic concentrations (<10.0 mcg/mL) of VCM were evaluated.

RESULTS

In total, 177 patients were categorized into the nomogram group, and 83 (47%), 81 (46%), and 13 patients (7%) had VCM trough concentrations of 10-20, <10, and >20 mcg/mL, respectively. Age <50 years was only significantly associated with subtherapeutic trough concentrations. Specific conditions of patients such as febrile neutropenia, solid tumor, and blood cancer were associated with elevated VCM clearance; however, there was no decline in trough VCM concentrations regardless of the presence of the specific conditions.

CONCLUSIONS

The Japanese VCM dosing nomogram was effective in minimizing the number of instances of supratherapeutic VCM serum concentrations; however, it lacked accuracy in achieving target trough concentrations. The accuracy of the nomogram could be enhanced by categorizing patients according to age. Nevertheless, this study provides novel evidence of the usefulness of this nomogram in avoiding subtherapeutic concentrations of VCM in patients with risk factors for augmented renal clearance.

β-Lactam Dosage Regimens in Septic Patients with Augmented Renal Clearance

Augmented renal clearance is commonly observed in septic patients and may result in insufficient β-lactam serum concentrations. The aims of this study were to evaluate potential correlations between drug concentrations or total body clearance of β-lactam antibiotics and measured creatinine clearance and to quantify the need for drug dosage adjustments in septic patients with different levels of augmented renal clearance.

Augmented renal clearance is commonly observed in septic patients and may result in insufficient β-lactam serum concentrations. The aims of this study were to evaluate potential correlations between drug concentrations or total body clearance of β-lactam antibiotics and measured creatinine clearance and to quantify the need for drug dosage adjustments in septic patients with different levels of augmented renal clearance. We reviewed 256 antibiotic measurements (512 drug concentrations) from a cohort of 215 critically ill patients who had a measured creatinine clearance of ≥120 ml/min and who received therapeutic drug monitoring of meropenem, cefepime, ceftazidime, or piperacillin from October 2009 until December 2014 at Erasme Hospital. Population pharmacokinetic (PK) analysis of the data was performed using the Pmetrics software package for R. Fifty-five percent of drug concentrations showed insufficient β-lactam serum concentrations to treat infections due to Pseudomonas aeruginosa. There were significant, yet weak, correlations between measured creatinine clearance and trough concentrations of meropenem (r = −0.21, P = 0.01), trough concentrations of piperacillin (r = −0.28, P = 0.0071), concentrations at 50% of the dosage interval (r = −0.41, P < 0.0001), and total body clearance of piperacillin (r = 0.39, P = 0.0002). Measured creatinine clearance adequately explained changes in drug concentrations in population pharmacokinetic models for cefepime, ceftazidime, and meropenem but not for piperacillin. Therefore, specific PK modeling can predict certain β-lactam concentrations based on renal function but not on absolute values of measured creatinine clearance, easily available for clinicians. Currently, routine therapeutic drug monitoring is required to adjust daily regimens in critically ill patients receiving standard dosing regimens.

A Randomized Pharmacokinetic and Pharmacodynamic Evaluation of Every 8-Hour and 12-Hour Dosing Strategies of Vancomycin and Cefepime in Neurocritically ill Patients

PURPOSE

Neurocritically ill patients have clinically significant alterations in pharmacokinetic parameters of renally eliminated medications that may result in subtherapeutic plasma and cerebrospinal fluid antibiotic concentrations.

METHODS

We conducted a prospective randomized open-label study of adult neurocritically ill patients treated with vancomycin and cefepime. Vancomycin 15 mg/kg and cefepime 2 g were dosed at every-8- or 12-hour intervals. The primary outcomes were the achievement of pharmacodynamic (PD) targets related to time of unbound drug above minimum inhibitory concentrations (MIC) for 60% or more of the dosing interval (fT > MIC ≥ 60%) for β-lactams and ratio of 24-hour area under the curve (AUC):MIC of 400 or greater for vancomycin.

RESULTS

Twenty patients were included in the study. They were divided equally between the every-12-hour and every-8-hour dosing groups. Patients (mean age 51.8 ± 11 yrs) were primarily male (60%) and white (95%), and most had an admission diagnosis of intracranial hemorrhage (80%). Compared with the every-12-hour group, the every-8-hour vancomycin group achieved target trough concentrations (higher than 15 μg/ml) significantly more frequently at initial measurement (0% vs 80%, p<0.01) and at 7-10 days (0% vs 90%, p=0.045) and achieved PD targets more frequently at increasing MICs. Similarly, compared with every-12-hour dosing, the every-8-hour cefepime dosing strategy significantly increased PD target attainment (fT > MIC ≥ 60%) at an MIC of 8 μg/ml (20% vs 70%, p=0.02).

CONCLUSIONS

This study demonstrated that more frequent dosing of vancomycin and cefepime is required to achieve optimal PD targets in adult neurocritically ill patients. The need for increased total daily doses is potentially secondary to the development of augmented renal clearance.

Reliability of serum creatinine-based formulae estimating renal function in non-critically ill surgery patients: Focus on augmented renal clearance

WHAT IS KNOWN AND OBJECTIVES

Formulae estimating glomerular filtration rate (GFR) are frequently used to guide drug dosing. The objectives of this prospective single-center study were to evaluate agreement between these equations and measured creatinine clearance (CrCl) in non-critically ill surgery patients with normal kidney function and augmented renal clearance (ARC, CrCl ≥ 130 mL/min/1.73 m²), to determine predictors for disagreement, define a GFR estimator cut-off value identifying ARC and determine the ARC prevalence and duration in non-critically ill surgical patients.

METHODS

Hospitalized adult non-critically ill abdominal and trauma surgery patients were eligible for inclusion. Measured CrCl based on an 8-hour urinary collection (CrCl_8h ) was used as the primary method for determining kidney function. Agreement between equations and measured CrCl_8h was assessed in terms of precision, defined as a bias within ±10 mL/min/1.73 m². Predictors for disagreement were identified for the most precise estimator using an ordinal logistic regression model with negative bias, agreement and positive bias as outcome variables. A receiver operating characteristic (ROC) analysis was performed to identify an estimator cut-off predicting ARC, which was subsequently applied for the daily proportion of patients displaying ARC and ARC duration.

RESULTS AND DISCUSSION

During the study period (14/11/2013 - 13/05/2014), in 232 adult non-critically ill abdominal and trauma surgery patients, all estimators tend to underestimate CrCl_8h (mean bias ranging from 17 to 22 mL/min/1.73 m²), especially in patients displaying ARC (mean bias ranging from 44 to 56 mL/min/1.73 m²). eGFR_CKD-EPI performed the best. Younger age and low ASA score independently predicted underestimation of CrCl_8h . Three different eGFR_CKD-EPI cut-offs with decreasing sensitivity and increasing specificity (84, 95 and 112 mL/min/1.73 m²) identified, respectively, 65%, 44% and 14% patients displaying ARC. The median ARC duration was 4, 4 and 3 days, respectively.

WHAT IS NEW AND CONCLUSION

In surgical patients, eGFR frequently underestimates measured CrCl, especially in young patients with low ASA score. eGFR cut-offs predicting ARC were identified.

Assessment of acute kidney injury in neurologically and traumatically injured intensive care patients receiving large vancomycin doses

Background:

Previous reports note that in a mixed patient population, vancomycin doses >4 g/day are associated with increased rates of acute kidney injury (AKI).

Objective:

The objective of the study is to determine if vancomycin regimens >4 g/day are associated with a higher incidence of AKI in neurocritical care unit (NCCU) and trauma/burn Intensive Care Unit (TBICU) patients.

Materials and Methods:

This single-centered, retrospective study enrolled adult patients initiated on vancomycin in the NCCU and TBICU at an academic medical center during 2016. Based on maximum steady-state dose exposure, patients were separated into two groups: ≤4 g/day and >4 g/day. The primary outcome of incidence of AKI was defined by the AKI Network criteria.

Results:

A total of 284 patients were screened for eligibility; 165 patients met inclusion criteria, 98 patients received ≤4 g/day and 67 patients received >4 g/day. The >4 g/day group had a lower mean age (32.6±11.1 vs. 47.8±16.2, P < 0.001), included more male patients (81% vs. 60%, P = 0.008), were more often treated for a central nervous system infection (31% vs. 11%, P = 0.001), had, on average, more concomitant use of nephrotoxic drugs (2.2±1.2 vs. 1.8±0.9, P = 0.02) and had a higher exposure to contrast (94% vs. 79%, P < 0.001). The primary outcome of AKI occurred in 14 patients receiving ≤4 g/day and five patients receiving >4 g/day which was not statistically significant (14% vs. 7%, P = 0.22).

Conclusions:

Our results indicate that administering >4 g/day of vancomycin to achieve therapeutic vancomycin troughs does not appear to lead to an increased incidence of AKI in a mixed NCCU and TBICU population.

Using Population Pharmacokinetic Modeling and Monte Carlo Simulations To Determine whether Standard Doses of Piperacillin in Piperacillin-Tazobactam Regimens Are Adequate for the Management of Febrile Neutropenia

Changes in the pharmacokinetics of piperacillin in febrile neutropenic patients have been reported to result in suboptimal exposures. This study aimed to develop a population pharmacokinetic model for piperacillin and perform dosing simulation to describe optimal dosing regimens for hematological malignancy patients with febrile neutropenia. Concentration-time data were obtained from previous prospective observational pharmacokinetic and interventional therapeutic drug monitoring studies. Nonparametric population pharmacokinetic analysis and Monte Carlo dosing simulations were performed with the Pmetrics package for R. A two-compartment model, with between-subject variability for clearance (CL), adequately described the data from 37 patients (21 males, age of 59 ± 12 years [means ± standard deviations] and weight of 77 ± 16 kg). Parameter estimates were CL of 18.0 ± 4.8 liters/h, volume of distribution of the central compartment of 14.3 ± 7.3 liters, rate constant for piperacillin distribution from the central to peripheral compartment of 1.40 ± 1.35 h^-1, and rate constant for piperacillin distribution from the peripheral to central compartment of 4.99 ± 7.81 h^-1 High creatinine clearance (CL_CR) was associated with reduced probability of target attainment (PTA). Extended and continuous infusion regimens achieved a high PTA of >90% for an unbound concentration of piperacillin remaining above the MIC (fT_>MIC) of 50%. Only continuous regimens achieved >90% PTA for 100% fT_>MIC when CL_CR was high. The cumulative fraction of response (FTA, for fractional target attainment) was suboptimal (<85%) for conventional regimens for both empirical and directed therapy considering 50% and 100% fT_>MIC FTA was maximized with prolonged infusions. Overall, changes in piperacillin pharmacokinetics and the consequences on therapeutic dosing requirements appear similar to those observed in intensive care patients. Guidelines should address the altered dosing needs of febrile neutropenic patients exhibiting high CL_CR or with known/presumed infections from high-MIC bacteria.

Augmented Renal Clearance in Critical Illness: An Important Consideration in Drug Dosing

Augmented renal clearance (ARC) is a manifestation of enhanced renal function seen in critically ill patients. The use of regular unadjusted doses of renally eliminated drugs in patients with ARC might lead to therapy failure. The purpose of this scoping review was to provide and up-to-date summary of the available evidence pertaining to the phenomenon of ARC. A literature search of databases of available evidence in humans, with no language restriction, was conducted. Databases searched were MEDLINE (1946 to April 2017), EMBASE (1974 to April 2017) and the Cochrane Library (1999 to April 2017). A total of 57 records were included in the present review: 39 observational studies (25 prospective, 14 retrospective), 6 case reports/series and 12 conference abstracts. ARC has been reported to range from 14-80%. ARC is currently defined as an increased creatinine clearance of greater than 130 mL/min/1.73 m² best measured by 8-24 h urine collection. Patients exhibiting ARC tend to be younger (<50 years old), of male gender, had a recent history of trauma, and had lower critical illness severity scores. Numerous studies have reported antimicrobials treatment failures when using standard dosing regimens in patients with ARC. In conclusion, ARC is an important phenomenon that might have significant impact on outcome in critically ill patients. Identifying patients at risk, using higher doses of renally eliminated drugs or use of non-renally eliminated alternatives might need to be considered in ICU patients with ARC. More research is needed to solidify dosing recommendations of various drugs in patients with ARC.