Identifying augmented renal clearance in trauma patients: Validation of the Augmented Renal Clearance in Trauma Intensive Care scoring system

Validation of Two Scoring Tools to Predict Risk of Augmented Renal Clearance in Trauma Patients

INTRODUCTION

Augmented renal clearance (ARC) is prevalent in trauma populations. Identification is underrecognized by calculated creatinine clearance or estimated glomerular filtration rate equations. Predictive scores may assist with ARC identification. The goal of this study was to evaluate validity of the ARCTIC score and ARC Predictor to predict ARC in critically ill trauma patients.

METHODS

This single center, retrospective study was performed at an academic level 1 trauma center. Critically ill adult trauma patients undergoing 24-h urine-collection were included. Patients with serum creatinine >1.5 mg/dL, kidney replacement therapy, suspected rhabdomyolysis, chronic kidney disease, or inaccurate urine collection were excluded. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for ARCTIC Score and ARC Predictor were calculated. Receiver operating characteristic curves were created for ARCTIC score and ARC Predictor models.

RESULTS

One-hundred and twenty-two patients with ARC and 78 patients without ARC were included. The ARCTIC score sensitivity, specificity, PPV, and NPV were 89%, 54%, 75%, and 75%, respectively. The ARC Predictor demonstrated sensitivity, specificity, PPV, and NPV of 77%, 88%, 91%, and 71%, respectively. Regression analyses revealed both ARCTIC score ≥6 and ARC Predictor threshold >0.5 as significant risk factors for ARC in presence of traumatic brain injury, obesity, injury severity score, and negative nitrogen balance (ARCTIC ≥6: odds ratio 8.59 [95% confidence interval 3.90-18.92], P < 0.001; ARC Predictor >0.5: odds ratio 20.07 [95% confidence interval 8.53-47.19], P < 0.001).

CONCLUSIONS

These findings corroborate validity of two pragmatic prediction tools to identify patients at high risk of ARC. Future studies evaluating correlations between ARCTIC score, ARC Predictor, and clinical outcomes are warranted.

Ampicillin-Sulbactam for Carbapenem-Susceptible Acinetobacter baumannii Pneumonia: A Case for High-Dose, Continuous Infusion Dosing Strategy in the Trauma ICU

Background: The optimal ampicillin-sulbactam dosing regimen for carbapenem-susceptible Acinetobacter baumannii isolates in critically ill trauma patients has not been clearly defined. One strategy to provide the adequate sulbactam dose includes high-dose continuous infusion. Case(s) Description: We present three cases of critically ill trauma patients with augmented renal clearance treated with high-dose ampicillin-sulbactam through an intravenous continuous infusion for ventilator-associated pneumonia. All A. baumannii isolates were susceptible to sulbactam with low minimum inhibitory concentrations. All achieved clinical cure at the end of therapy and no recurrent pneumonia was noted. No clinically substantial adverse effect attributable to ampicillin-sulbactam therapy occurred. Discussion: There is limited evidence to endorse high-dose, continuous infusion ampicillin-sulbactam for treatment of infections caused by carbapenem-susceptible A. baumannii. This report presents three critically ill trauma patients with augmented renal clearance that achieved positive clinical outcomes with higher doses of ampicillin-sulbactam administered through a continuous infusion.

Pharmacokinetics of Levetiracetam Seizure Prophylaxis in Severe Traumatic Brain Injury

BACKGROUND

Drug pharmacokinetics (PK) are altered in neurocritically ill patients, and optimal levetiracetam dosing for seizure prophylaxis is unknown.

OBJECTIVE

This study evaluates levetiracetam PK in critically ill patients with severe traumatic brain injury (sTBI) receiving intravenous levetiracetam 1000 mg every 8 (LEV8) to 12 (LEV12) hours for seizure prophylaxis.

METHODS

This prospective, open-label study was conducted at a level 1 trauma, academic, quaternary care center. Patients with sTBI receiving seizure prophylaxis with LEV8 or LEV12 were eligible for enrollment. Five sequential, steady-state, postdose serum levetiracetam concentrations were obtained. Non-compartmental analysis (NCA) and compartmental approaches were employed for estimating pharmacokinetic parameters and projecting steady-state trough concentrations. Pharmacokinetic parameters were compared between LEV8 and LEV12 patients. Monte Carlo simulations (MCS) were performed to determine probability of target trough attainment (PTA) of 6 to 20 mg/L. A secondary analysis evaluated PTA for weight-tiered levetiracetam dosing.

RESULTS

Ten male patients (5 LEV8; 5 LEV12) were included. The NCA-based systemic clearance and elimination half-life were 5.3 ± 1.2 L/h and 4.8 ± 0.64 hours. A one-compartment model provided a higher steady-state trough concentration for the LEV8 group compared with the LEV12 group (13.7 ± 4.3 mg/L vs 6.3 ± 1.7 mg/L; P = 0.008). Monte Carlo simulations predicted regimens of 500 mg every 6 hours, 1000 mg every 8 hours, and 2000 mg every 12 hours achieved therapeutic target attainment. Weight-tiered dosing regimens achieved therapeutic target attainment using a 75 kg breakpoint.

CONCLUSION AND RELEVANCE

Neurocritically ill patients exhibit rapid levetiracetam clearance resulting in a short elimination half-life. Findings of this study suggest regimens of levetiracetam 500 mg every 6 hours, 1000 mg every 8 hours, or 2000 mg every 12 hours may be required for optimal therapeutic target attainment. Patient weight of 75 kg may serve as a breakpoint for weight-guided dosing to optimize levetiracetam therapeutic target attainment for seizure prophylaxis.

Predictors of augmented renal clearance based on iohexol plasma clearance in critically ill children

BACKGROUND

Augmented renal clearance (ARC) holds a risk of subtherapeutic drug concentrations. Knowledge of patient-, disease-, and therapy-related factors associated with ARC would allow predicting which patients would benefit from intensified dosing regimens. This study aimed to identify ARC predictors and to describe ARC time-course in critically ill children, using iohexol plasma clearance (CLiohexol) to measure glomerular filtration rate (GFR).

METHODS

This is a retrospective analysis of data from the "IOHEXOL" study which validated GFR estimating formulas (eGFR) against CLiohexol. Critically ill children with normal serum creatinine were included, and CLiohexol was performed as soon as possible after pediatric intensive care unit (PICU) admission (CLiohexol1) and repeated (CLiohexol2) after 48-72 h whenever possible. ARC was defined as CLiohexol exceeding normal GFR for age plus two standard deviations.

RESULTS

Eighty-five patients were included; 57% were postoperative patients. Median CLiohexol1 was 122 mL/min/1.73 m2 (IQR 75-152). Forty patients (47%) expressed ARC on CLiohexol1. Major surgery other than cardiac surgery and eGFR were found as independent predictors of ARC. An eGFR cut-off value of 99 mL/min/1.73 m2 and 140 mL/min/1.73 m2 was suggested to identify ARC in children under and above 2 years, respectively. ARC showed a tendency to persist on CLiohexol2.

CONCLUSIONS

Our findings raise PICU clinician awareness about increased risk for ARC after major surgery and in patients with eGFR above age-specific thresholds. This knowledge enables identification of patients with an ARC risk profile who would potentially benefit from a dose increase at initiation of treatment to avoid underexposure.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05179564, registered retrospectively on January 5, 2022.

Exposure levels and target attainment of piperacillin/tazobactam in adult patients admitted to the intensive care unit: a prospective observational study

PURPOSE

The objective of this study was to evaluate the exposure and the pharmacodynamic target attainment of piperacillin/tazobactam (PTZ) in adult critically ill patients.

METHODS

We conducted a prospective observational study in the intensive care unit (ICU) of the Hôpital du Sacré-Cœur de Montréal (a Level I trauma centre in Montreal, QC, Canada) between January 2021 and June 2022. We included patients aged 18 yr or older admitted to the ICU who received PTZ by intravenous administration. Demographic and clinical characteristics were collected, and clinical scores were calculated. On study day 1 of antimicrobial therapy, three blood samples were collected at the following timepoints: one hour after PTZ dose administration and at the middle and at the end of the dosing interval. The sampling schedule was repeated on days 4 and 7 of therapy if possible. Samples were analyzed by ultra-high performance liquid chromatography with diode array detector to determine the total piperacillin concentration. Middle- and end-of-interval concentrations were used for target attainment analyses, and were defined as a concentration above the minimal inhibitory concentration of 16 mg·L-1, corresponding to the breakpoint of Enterobacteriaceae and Pseudomonas aeruginosa.

RESULTS

Forty-three patients were recruited and 202 blood samples were analyzed. The most prevalent dose was 3/0.375 g every six hours (n = 50/73 doses administered, 68%) with a 30-min infusion. We observed marked variability over the three sampling timepoints, and the median [interquartile range] piperacillin concentrations at peak, middle of interval, and end of interval were 109.4 [74.0-152.3], 59.3 [21.1-74.4], and 25.3 [6.8-44.6] mg·L-1, respectively. When assessing target attainment, 37% of patients did not reach the efficacy target of a trough concentration of 16 mg·L-1. The majority of patients who were underexposed were patients with normal to augmented renal clearance.

CONCLUSION

In this prospective observational study of adult ICU patients receiving intravenous PTZ, a large proportion had subtherapeutic concentrations of piperacillin. This was most notable in patients with normal to augmented renal clearance. More aggressive dosage regimens may be required for this subpopulation to ensure attainment of efficacy targets.

Enhanced renal clearance impacts levetiracetam concentrations in patients with traumatic brain injury with and without augmented renal clearance

BACKGROUND

The purpose of this study was to examine the impact of ARC on levetiracetam concentrations during the first week following acute TBI. The hypothesis was levetiracetam concentrations are significantly lower in TBI patients with augmented renal clearance (ARC) compared to those with normal renal clearance.

METHODS

This is a prospective cohort pharmacokinetic study of adults with moderate to severe TBI treated with levetiracetam during the first week after injury. Serial blood collections were performed daily for analysis of levetiracetam, cystatin C, and 12-hr creatinine clearance (CrCl) determinations. Patients were divided into two cohorts: with (CrCl ≥130 ml/min/1.73 m2) and without ARC.

RESULTS

Twenty-two patients with moderate to severe TBI were included. The population consisted primarily of young male patients with severe TBI (mean age 40 years old, 68% male, median admission GCS 4). Each received levetiracetam 1000 mg IV every 12 h for the study period. ARC was present in 77.3% of patients, with significantly lower levetiracetam concentrations in ARC patients and below the conservative therapeutic range (< 6mcg/mL) for all study days. In patients without ARC, the serum concentrations were also below the expected range on all but two study days (Days 4 and 5). Four of the 22 (18.2%) patients exhibited seizure activity during the study period (two of these patients exhibited ARC). Cystatin C concentrations were significantly lower in patients with ARC, though the mean for all patients was within the typical normal range.

CONCLUSIONS

ARC has a high prevalence in patients with moderate to severe TBI. Levetiracetam concentrations after standard dosing were low in all TBI patients, but significantly lower in patients with ARC. This study highlights the need to consider personalized drug dosing in TBI patients irrespective of the presence of ARC.

CLINICAL TRIAL REGISTRATION

This study was registered at cliicaltrials.gov (NCT02437838) Registered on 08/05/2015, https://clinicaltrials.gov/ct2/show/NCT02437838 .

Potential benefits of therapeutic drug monitoring for beta-lactam antibiotics in augmented renal clearance patients: a case report

Augmented renal clearance (ARC) is commonly described in critically ill patients, making drug pharmacokinetics even harder to predict in this population. This case report displays the value of therapeutic drug monitoring (TDM) of piperacillin/tazobactam (PTZ) in this population. We identified two patients with ARC and intermittent administration of PTZ who took part in a prospective, descriptive study conducted at Hôpital du Sacré-Cœur de Montréal. Both had plasma samples drawn at peak, middle, and end of their dosing intervals of PTZ. Minimal inhibitory concentrations (MICs) of 4 and 8 mg/L were chosen to evaluate therapeutic target attainment at middle and end of dosing interval. The first patient was a 52-year-old male with a renal clearance rate estimated at 147 mL/min who received 3.375 g PTZ every 6 h. The second patient, a 49-year-old male, had an estimated renal clearance rate of 163 mL/min and received the same regimen. Both patients had piperacillin concentrations above the target MICs at middle of the dosing interval, but they failed to reach a trough concentration above 8 mg/L. The present case report showcases two patients with subtherapeutic PTZ concentrations despite strict following of local administration protocols. This suboptimal administration could not only lead to treatment failure, but also to the selection and growth of resistant pathogens. Implementing TDM would offer the possibility to adjust drug regimens in real-time and prevent situations like these from occurring.

Augmented Renal Clearance in the Hematology and Oncology Populations: A Scoping Review for Pharmacists

INTRODUCTION

Until recently, interest in renal function has focused on impairment to limit drug toxicity and increase medication safety. Augmented renal clearance (ARC) has been increasingly studied in multiple patient populations, including oncology, and could lead to decreased drug efficacy from faster elimination resulting in subtherapeutic concentrations. This scoping review sought to summarize ARC literature in cancer and identify areas of research to better inform pharmacy practitioners.

DATA SOURCES

Electronic databases were searched for English articles related to augmented/enhanced renal function/clearance following a framework for scoping reviews.

DATA SYNTHESIS

Fourteen articles were analyzed, divided according to article objective: descriptive studies or ARC's impact on pharmacokinetics/pharmacodynamics. ARC was most defined as creatinine clearance >130 mL/min/1.73 m2, reported in 10%-100% of patients. Febrile neutropenia in adult and pediatric patients, and age <50-65 years, hematologic malignancy, and lower serum creatinine in adult patients were notable risk factors for ARC. The impact of ARC has only been evaluated with antimicrobial agents consistently resulting in lower than anticipated trough levels. Identified gaps include: elucidation of ARC's mechanism and associated biomarkers, an inclusive ARC definition for relative renal enhancement, and study of additional drug classes to ascertain the breadth of ARC impact on drug therapy.

CONCLUSIONS

ARC is proving to be a frequent phenomenon in patients with cancer which pharmacists could play a vital role. Further research is needed to better understand the impact of ARC in patient care and a potential need to stage ARC based on degree of renal enhancement to establish specific drug dosing recommendations.

Augmented Renal Function in Burn Patients: Occurrence and Discordance With Commonly Used Methods to Assess Renal Function

Augmented renal clearance (ARC) is defined by supraphysiologic renal function and is associated with drug failure due to subtherapeutic drug exposure. Burn patients are cited as being at high risk for ARC, yet rates of ARC have not been well described. This retrospective study described the prevalence and incidence of ARC, and compared 12-hour urine collection values (CrCl-12) vs. common estimates of renal function in assessed patients at an American Burn Association-verified burn center. All thermally injured burn patients with a CrCl-12 result were included. ARC was defined as a CrCl-12 >130 ml/min. Cockcroft-Gault, modification of diet in renal disease (MDRD), and CKD-EPI-2021 estimates were calculated. Over 13 months, 163 CrCl-12 results were collected in 68 patients at a median of 9 days from admission with an average value of 160 ml/min. The median total body surface area (total body surface area [TBSA]%) was 17.25%. ARC prevalence was 70.6% with an incidence of 66.3% in all CrCl-12 assessments. Those with ARC were less likely to have heart failure, P = .007. Age, TBSA%, and trauma were not different between those with or without ARC. ARC incidences in those with TBSAs of ≥20%, <20%, or <10%, were 70.5%, 58.6%, and 76.7%, respectively. Agreement of Cockcroft-Gault, MDRD, and CKD-EPI-2021 to CrCl-12 was moderate to weak and frequently failed to identify ARC. ARC is common in burn patients, regardless of TBSA%. Widely accepted estimations of renal function may be incorrect resulting in under-dosing of medications. Additional research is required to identify burn patients at greatest risk for ARC and subsequent dosing strategies to maintain pharmacologic efficacy without unduetoxicity.

Glomerular hyperfiltration in patients with severe trauma

BACKGROUND AND OBJECTIVE

Augmented renal clearance or glomerular hyperfiltration (GHF) can significantly affect the clinical outcomes of renally eliminated drugs by promoting subtherapeutic drug exposure. The aggression suffered in patients who suffer severe trauma is a predisposition to manifest GHF and the identification of these patients remains a clinical challenge. The main objective of this study was to describe the prevalence of GHF in a cohort of critically ill trauma patients.

MATERIALS AND METHODS

Prospective observational study of a cohort of adult patients admitted after suffering severe trauma or polytrauma in the Anesthesiology ICU of the University Hospital of Albacete (Spain). Creatinine clearance (ClCr) was calculated in a 4-h urine collection sample at 24, 72 and 168 h after admission applying the formula; CrCl: [Diuresis in ml (urine/4 h) × Creatinine in urine (mg/dl)] ÷ [240 (minutes) × Creatinine in plasma (mg/dl)]. A CrCl above 130 mL/min was considered GHF. The analyses were performed with the statistical software R version 4.0.4.

RESULTS

85 patients were included. The median age of the patients was 51 years (IQR 26), 78.82% male. 68 patients were male (78.82%). 75.29% of the patients were polytraumatized. 61 patients (71.76%) presented GHF at some point in the CrCl determination. At 24 h of admission, 56.34% of the patients presented GHF with a mean CrCl of 195.8 ml/min, 61.11% of the patients presented it at 72 h with a mean CrCl of /min and 56.52% presented GHF at 168 h of admission with a mean CrCl of 207 ml/min. A significant positive relationship (p = 0.07) was found between GHF manifested at 72 h and at 168 h. We observed a statistically significant relationship between this phenomenon with younger ages, lower ISS scores and lower plasma creatinines.

CONCLUSIONS

GHF are a common condition in critically ill patients admitted for severe trauma. We recommend the use of CrCl to assess renal function and make dosage adjustments. Studies are required to understand the clinical impact of these phenomena on drug elimination and to be able to establish the ideal dosage in those cases.

Performance of different body weights in the Cockcroft-Gault equation in critically ill patients with and without augmented renal clearance: A multicenter cohort

STUDY OBJECTIVE

The primary objective was to evaluate the performance of the Cockcroft-Gault (CG) equation with different body weights (BWs) compared to a measured creatinine clearance (mCrCl) in an intensive care unit (ICU) population with and without augmented renal clearance (ARC).

DESIGN

Multicenter, retrospective cohort.

SETTING

Two ICUs in the United States and four ICUs from a previous international observational analysis.

PATIENTS

Adult ICU patients admitted from January 1, 2010 to July 30, 2020 with at least one mCrCl collected within the initial 10 days of hospitalization were eligible for inclusion.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the performance of the CG equation in ARC (mCrCl≥130 ml/min/1.73 m2 ) and non-ARC (mCrCl<130 ml/min/1.73 m2 ) patients. Correlation was analyzed by Pearson's correlation coefficient, bias by mean difference, and accuracy by the percentage of patients within 30% of the mCrCl. A total of 383 patients were included, which provided 1708 mCrCl values. The majority were male (n = 239, 62%), median age of 55 years [IQR 40-65] with a surgical diagnosis (n = 239, 77%). ARC was identified in 229 (60%) patients. The ARC group had lower Scr values (0.6 [0.5-0.7] vs. 0.7 [0.6-0.9] mg/dl, p < 0.001) and higher mCrCl (172.8 (SD 39.1) vs. 89.9 mL/min/1.73 m2 (SD 25.4), p < 0.001) compared with the non-ARC group, respectively. Among non-ARC patients there was a moderate correlation (r = 0.33-0.39), moderate accuracy (range 48-58%), and low bias (range of -12.9 to 17.1) among the different BW estimations with the adjusted BW having the better performance. Among ARC patients there was low correlation (r = 0.24-0.28), low to moderate accuracy (range 38-70%), and high bias (range of -58.5 to -21.6).

CONCLUSIONS

The CG-adjusted BW had the best performance in the non-ARC patients, while CG performed poorly with any BW in ARC patients. Although the CG equation remains the standard equation for estimating CrCl in the ICU setting, a new, validated equation is needed for patients with ARC.

Concordance between glomerular filtration rate estimation equations and 4-hour urinary creatinine clearance in critically ill patients with severe trauma

BACKGROUND AND OBJECTIVE

There is a growing body of evidence that the equations used to estimate the glomerular filtration rate (GFR) are not suitable in critically ill patients, a population whose GFR fluctuates continuously. Glomerular filtration is usually estimated by measuring urine creatinine clearance (CrCl) at various time points. The aim of our study was to evaluate the performance of the most widely used GFR calculators in the subpopulation of critically ill patients admitted for severe trauma, and to compare the results against determinations of CrCl in urine collected over a 4-h period (4h-CrCl).

MATERIAL AND METHODS

Observational study in patients hospitalized for severe trauma. We measured the 4h-CrCl and estimated GFR using the Cockcroft-Gault, modified Jelliffe, MDRD, t-MDRD, and CKD-EPI equations, adjusting the results for body surface area (BSA) (ml/min/1.73m2). Data were analysed using R version 4.0.4.

RESULTS

A total of 85 patients were included. Median age was 51 years, and 68 were men (78.82%). The mean BSA-adjusted 4h-CrCl (4h-ClCr/1.73m2) was 84.5 ml/min/1.73m2. We found that GFR estimated using the t-MDRD equation correlated significantly with 4h-CrCl/1.73m2. The Cockcroft-Gault equation correlated significantly with 4h-CrCl/1.73m2 when GFR was greater than 130ml/min/m2.

CONCLUSIONS

In ICU patients, glomerular filtration can be reliably estimated by determining urine CrCl, but GFR calculators are not accurate in this population.

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.

Development and validation of the creatinine clearance predictor machine learning models in critically ill adults

BACKGROUND

In critically ill patients, measured creatinine clearance (CrCl) is the most reliable method to evaluate glomerular filtration rate in routine clinical practice and may vary subsequently on a day-to-day basis. We developed and externally validated models to predict CrCl one day ahead and compared them with a reference reflecting current clinical practice.

METHODS

A gradient boosting method (GBM) machine-learning algorithm was used to develop the models on data from 2825 patients from the EPaNIC multicenter randomized controlled trial database. We externally validated the models on 9576 patients from the University Hospitals Leuven, included in the M@tric database. Three models were developed: a "Core" model based on demographic, admission diagnosis, and daily laboratory results; a "Core + BGA" model adding blood gas analysis results; and a "Core + BGA + Monitoring" model also including high-resolution monitoring data. Model performance was evaluated against the actual CrCl by mean absolute error (MAE) and root-mean-square error (RMSE).

RESULTS

All three developed models showed smaller prediction errors than the reference. Assuming the same CrCl of the day of prediction showed 20.6 (95% CI 20.3-20.9) ml/min MAE and 40.1 (95% CI 37.9-42.3) ml/min RMSE in the external validation cohort, while the developed model having the smallest RMSE (the Core + BGA + Monitoring model) had 18.1 (95% CI 17.9-18.3) ml/min MAE and 28.9 (95% CI 28-29.7) ml/min RMSE.

CONCLUSIONS

Prediction models based on routinely collected clinical data in the ICU were able to accurately predict next-day CrCl. These models could be useful for hydrophilic drug dosage adjustment or stratification of patients at risk.

TRIAL REGISTRATION

Not applicable.

LC-MS/MS-Based Serum Metabolomics and Transcriptome Analyses for the Mechanism of Augmented Renal Clearance

Augmented Renal Clearance (ARC) refers to the increased renal clearance of circulating solute in critically ill patients. In this study, the analytical research method of transcriptomics combined with metabolomics was used to study the pathogenesis of ARC at the transcriptional and metabolic levels. In transcriptomics, 534 samples from 5 datasets in the Gene Expression Omnibus database were analyzed and 834 differential genes associated with ARC were obtained. In metabolomics, we used Ultra-Performance Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry to determine the non-targeted metabolites of 102 samples after matching propensity scores, and obtained 45 differential metabolites associated with ARC. The results of the combined analysis showed that purine metabolism, arginine biosynthesis, and arachidonic acid metabolism were changed in patients with ARC. We speculate that the occurrence of ARC may be related to the alteration of renal blood perfusion by LTB4R, ARG1, ALOX5, arginine and prostaglandins E2 through inflammatory response, as well as the effects of CA4, PFKFB2, PFKFB3, PRKACB, NMDAR, glutamate and cAMP on renal capillary wall permeability.

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.

External Validation of the Augmented Renal Clearance Predictor in Critically Ill COVID-19 Patients

The ARC predictor is a prediction model for augmented renal clearance (ARC) on the next intensive care unit (ICU) day that showed good performance in a general ICU setting. In this study, we performed a retrospective external validation of the ARC predictor in critically ill coronavirus disease 19 (COVID-19) patients admitted to the ICU of the University Hospitals Leuven from February 2020 to January 2021. All patient-days that had serum creatinine levels available and measured creatinine clearance on the next ICU day were enrolled. The performance of the ARC predictor was evaluated using discrimination, calibration, and decision curves. A total of 120 patients (1064 patient-days) were included, and ARC was found in 57 (47.5%) patients, corresponding to 246 (23.1%) patient-days. The ARC predictor demonstrated good discrimination and calibration (AUROC of 0.86, calibration slope of 1.18, and calibration-in-the-large of 0.14) and a wide clinical-usefulness range. At the default classification threshold of 20% in the original study, the sensitivity and specificity were 72% and 81%, respectively. The ARC predictor is able to accurately predict ARC in critically ill COVID-19 patients. These results support the potential of the ARC predictor to optimize renally cleared drug dosages in this specific ICU population. Investigation of dosing regimen improvement was not included in this study and remains a challenge for future studies.

Onset timing and duration of augmented renal clearance in a mixed intensive care unit

BACKGROUND

Augmented renal clearance (ARC) is associated with lower blood plasma concentrations of renally excreted drugs; however, its time course is unknown. The current study aimed to determine the onset timing/duration of ARC, its risk factors, and its association with clinical outcomes by continuous monitoring of urinary creatinine clearance (CrCl) in critically ill patients.

METHODS

Data were retrospectively obtained from the medical records of 2592 critically ill patients admitted to the intensive care unit (ICU) from January 2019 to June 2022 at a tertiary emergency hospital. Among these, patients with continuously measured urinary CrCl were selected and observed over time. We evaluated the onset timing and duration of ARC by plotting Kaplan-Meier curves. Furthermore, by multivariate analyses, factors associated with the onset and persistence of ARC were analyzed, and the association between the ARC time course and clinical outcomes was evaluated.

RESULTS

The prevalence of ARC was 33.4% (245/734). ARC onset was within 3 days of admission in approximately half of the cases, and within 1 week in most of the other cases. In contrast, the persistence duration of ARC varied widely (median, 5 days), and lasted for more than a month in some cases. Multivariate analysis identified younger age, male sex, lower serum creatinine at admission, admission with central nervous system disease, no medical history, use of mechanically assisted ventilation, and vasopressor use as onset factors for ARC. Furthermore, factors associated with ARC persistence such as younger age and higher urinary CrCl on ARC day 1 were detected. The onset of ARC was significantly associated with reduced mortality, but persistent of ARC was significantly associated with fewer ICU-free days.

CONCLUSIONS

Despite the early onset of ARC, its duration varied widely and ARC persisted longer in younger patients with higher urinary CrCl. Since the duration of ARC was associated with fewer ICU-free days, it may be necessary to consider a long-term increased-dose regimen of renally excreted drugs beginning early in patients who are predicted to have a persistent ARC.

Augmented Renal Clearance in Patients with Acute Ischemic Stroke: A Prospective Observational Study

BACKGROUND

Augmented renal clearance (ARC) is a phenomenon that has been demonstrated in many subsets of critically ill patients and is characterized by a creatinine clearance (CrCl) > 130 mL/min. Prior research has examined ARC prevalence in the presence of sepsis, traumatic brain injury, subarachnoid hemorrhage, and intracranial hemorrhage. However, to our knowledge, no studies have examined whether this phenomenon occurs in patients suffering from an acute ischemic stroke (AIS). The objective of this study was to evaluate whether patients experiencing an AIS exhibit ARC, identify potential contributing factors, and examine the precision of current renal clearance estimation methods in patients with AIS experiencing ARC.

METHODS

This was a single-center prospective observational study conducted in adult patients admitted to a neurocritical intensive care unit (ICU) at a community hospital. Once consent was gained, patients with an admitting diagnosis of an AIS underwent a 24-h urine collection to assess measured CrCl. The primary end point assessed for ARC, defined as a measured CrCl > 130 mL/min. The secondary end point evaluated length of stay in the neurocritical ICU.

RESULTS

Twenty-eight patients met enrollment criteria, and data was analyzed for 20 patients. ARC was present in 35% of enrolled patients. Mathematical estimations of renal function were inadequate in detecting ARC manifestation. Patients experiencing ARC were associated with nonsignificantly shorter ICU length of stay.

CONCLUSIONS

ARC appears to manifest in patients with AIS inconsistently. Patients experiencing ARC were associated with nonsignificantly shorter ICU length of stay.

Evaluation of vancomycin pharmacokinetics in patients with augmented renal clearances: A randomized clinical trial

Purpose: Vancomycin is a narrow therapeutic window glycopeptide antibiotic that acts against Gram-positive bacteria. As it is renally eliminated, therapeutic drug monitoring is recommended for vancomycin, especially in case of kidney function alteration. Augmented renal clearance (ARC), defined as a creatinine clearance of more than 130 ml/min, is a risk factor for sub-therapeutic concentrations of vancomycin. This study aimed to evaluate the vancomycin pharmacokinetics following the administration of two different regimens in ARC patients.

Methods: A randomized clinical trial (IRCT20180802040665N1) was conducted on patients in need of vancomycin therapy. Eight hours of urine was collected and 56 patients divided into two groups with creatinine clearance of more than 130 ml/min were included in the study. The first group received 15 mg/kg of vancomycin every 12 h and the second group 15 mg/kg every 8 h. After four doses, the peak and trough concentrations were measured from two blood samples. The primary outcome was the percentage of patients who attainted AUC more than 400. The occurrence of acute kidney injury also was evaluated after seven days.

Results: The mean age of patients in the every 12 h and every 8 h groups was 44.04 ± 16.55 and 42.86 ± 11.83 years, respectively. While neurosurgical issues were the most common causes of hospitalization, central nervous infections were the most common indications for vancomycin initiation. Urinary creatinine clearance was 166.94 ± 41.32 ml/min in the every 12 h group and 171.78 ± 48.56 ml/min in the every 8 h group. 46.42% of patients in the every 12 h group and 82.14% of patients in the every 8 h group attained AUC/MIC of more than 400 mg × hr/L. None of the patients in the every 12 h group reached more than 15 mcg/ml concentration. At the 7-day follow-up, 10.7% patients in the BD group and 28.6% patients in the TDS group developed acute kidney injury (p = 0.089).

Conclusion: Administration of vancomycin at a dose of 15 mg/kg every 8 h is associated with higher pharmacokinetic attainment in ARC patients. The occurrence of acute kidney injury also was not significantly higher in this therapeutic regimen. AUC/MIC monitoring is necessary in this population.

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.

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).

Investigation of pharmacokinetic and clinical outcomes of various meropenem regimens in patients with ventilator-associated pneumonia and augmented renal clearance

INTRODUCTION

Augmented renal clearance (ARC) defined as creatinine clearance (Clcr) above 130 mL/min/1.73m² may lead to suboptimal antibacterial treatment. The aim of this study was to determine a strategy for meropenem administration to achieve both pharmacodynamic-pharmacokinetic (PK-PD) target (50%fT > MIC) and better clinical outcomes in patients with VAP and ARC.

MATERIALS AND METHODS

In this randomized clinical trial, patients with VAP and high risk for ARC were recruited. An 8-h urine collection was performed on the 1st, 3rd, and 5th days of study to measure Clcr. Included patients were divided into three groups: (1) 1 g meropenem, 3-h infusion, (2) 2 g meropenem, 3-h infusion, (3) 1 g meropenem, 6-h infusion. On the 2nd, 3rd, and 5th days of treatment, peak and trough blood samples were collected to undergo HPLC assay. MICs were assessed using microdilution method. Patients were also clinically monitored for 14 days.

RESULTS

Forty-five patients were included. Group 3 showed significanty higher rate of patients achieving fT > MIC > 50% (100% for group 3 versus 40% for group 2 and 13% for group 1; p = 0.0001). Mean fT > MIC% was significantly higher in group 3 (78.77 ± 5.87 for group 3 versus 49.6 ± 7.38 for group 2 and 43.2 ± 7.98 for group 1; p = 0.0001). Statistical analysis showed no significant differences among groups regarding clinical improvement.

CONCLUSION

According to the findings of this trial, prolonged meropenem infusion is an appropriate strategy compared to dose elevation among ARC patients.

The impact of early target attainment of vancomycin in critically ill patients with confirmed Gram-positive infection: A retrospective cohort study

BACKGROUND

Vancomycin is a commonly used antibiotic in critically ill patients for various indications. Critical illness imposes pharmacokinetic-pharmacodynamics challenges, which makes optimizing vancomycin in this population cumbersome. Data are scarce on the clinical impact of time to therapeutic trough levels of vancomycin in critically ill patients.  This study aims to evaluate the timing to achieve therapeutic trough level of vancomycin on 30-day mortality in critically ill patients.

METHOD

A retrospective cohort study was conducted for all adult critically ill patients with confirmed Gram-positive infection who received IV vancomycin between January 1, 2017, and December 31, 2020. We compared early (< 48 h) versus late (≥ 48 h) attainment of vancomycin therapeutic trough levels. The primary outcome was the 30-day mortality in critically ill patients. Secondary outcomes were the development of resistant organisms, microorganisms eradication within 4-5 days of vancomycin initiation, acute kidney injury (AKI), and length of stay (LOS). Propensity score-matched (1:1 ratio) used based on patient's age, serum creatinine, and albumin values at baseline.

RESULTS

A total of 326 patients were included; 110 patients attained the therapeutic trough levels within 48 h of vancomycin initiation. Late achievement of the therapeutic trough levels was associated with higher 30-day mortality (HR: 2.54; 95% CI [1.24-5.22]; p = 0.01). Additionally, patients who achieved therapeutic trough levels of vancomycin late were more likely to develop AKI (OR = 2.59; 95% CI [1.01-6.65]; p = 0.04). Other outcomes were not statistically significant between the two groups.

CONCLUSION

Early achievement of vancomycin therapeutic levels in patients with confirmed Gram-positive infection was associated with possible survival benefits.

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.

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.

Development and External Validation of an Online Clinical Prediction Model for Augmented Renal Clearance in Adult Mixed Critically Ill Patients: The Augmented Renal Clearance Predictor

OBJECTIVES

Augmented renal clearance might lead to subtherapeutic plasma levels of drugs with predominant renal clearance. Early identification of augmented renal clearance remains challenging for the ICU physician. We developed and validated our augmented renal clearance predictor, a clinical prediction model for augmented renal clearance on the next day during ICU stay, and made it available via an online calculator. We compared its predictive performance with that of two existing models for augmented renal clearance.

DESIGN

Multicenter retrospective registry-based cohort study.

SETTING

Three Belgian tertiary care academic hospitals.

PATIENTS

Adult medical, surgical, and cardiac surgery ICU patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Development of the prediction model was based on clinical information available during ICU stay. Out of 33,258 ICU days, we found augmented renal clearance on 19.6% of all ICU days in the development cohort. We retained six clinical variables in our augmented renal clearance predictor: day from ICU admission, age, sex, serum creatinine, trauma, and cardiac surgery. We assessed performance by measuring discrimination, calibration, and net benefit. We externally validated the final model in a single-center population (n = 10,259 ICU days). External validation confirmed good performance with an area under the curve of 0.88 (95% CI 0.87-0.88) and a sensitivity and specificity of 84.1 (95% CI 82.5-85.7) and 76.3 (95% CI 75.4-77.2) at the default threshold probability of 0.2, respectively.

CONCLUSIONS

Augmented renal clearance on the next day can be predicted with good performance during ICU stay, using routinely collected clinical information that is readily available at bedside. Our augmented renal clearance predictor is available at www.arcpredictor.com.

Augmented Renal Clearance Following Traumatic Injury in Critically Ill Patients Requiring Nutrition Therapy

The intent of this study was to ascertain the prevalence of augmented renal clearance (ARC) in patients with traumatic injuries who require nutrition therapy and identify factors associated with ARC. Adult patients admitted to the trauma intensive care unit from January 2015 to September 2016 who received enteral or parenteral nutrition therapy and had a 24 h urine collection within 4 to 14 days after injury were retrospectively evaluated. Patients with a serum creatinine concentration > 1.5 mg/dL, required dialysis, or had an incomplete urine collection were excluded. ARC was defined as a measured creatinine clearance > 149 mL/min/1.73 m². Two hundred and three patients were evaluated. One hundred and two (50%) exhibited ARC. A greater proportion of patients with ARC were male (86% vs. 67%; p = 0.004), had traumatic brain injury (33% vs. 9%; p = 0.001), a higher injury severity score (30 ± 11 vs. 26 ± 12; p = 0.015), were younger (36 ± 15 vs. 54 ± 17 years; p = 0.001), had a lower serum creatinine concentration (0.7 ± 2 vs. 0.9 ± 0.2 mg/dL; p = 0.001) and were more catabolic (nitrogen balance of −10.8 ± 13.0 vs. −6.2 ± 9.2 g/d; p = 0.004). The multivariate analysis revealed African American race and protein intake were also associated with ARC. Half of critically ill patients with traumatic injuries experience ARC. Patients with multiple risk factors for ARC should be closely evaluated for dosing of renally-eliminated electrolytes, nutrients, and medications.

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.

Pharmacokinetics of levetiracetam in neurosurgical ICU patients

BACKGROUND/OBJECTIVES

The pharmacokinetics (PK) of drugs is dramatically altered in critical illness. Augmented renal clearance (ARC), a phenomenon characterized by creatinine clearance (CrCl) greater than 130 ml/min/1.73m², is commonly described in critically ill patients. Levetiracetam, an antiepileptic drug commonly prescribed for seizure prophylaxis in the neurosurgical ICU, undergoes predominant elimination via the kidneys. Hence, we hypothesize that current dosing practice of intravenous (IV) levetiracetam 500 mg twice daily is inadequate for critically ill patients due to enhanced drug elimination. The objectives of our study were to describe the population PK of levetiractam using a nonparametric approach to design an optimal dosing regimen for critically ill neurosurgical patients.

METHODS

This was a prospective, observational, population PK study. Serial blood samples were obtained from neurosurgical ICU patients who received at least one dose of IV levetiracetam. We used uHPLC to analyze these samples and Pmetrics™ software to perform PK analysis.

RESULTS

Twenty subjects were included, with a median age of 54 years and CrCl of 104 ml/min. A two-compartmental model with linear elimination adequately described the profile of levetiracetam. Mean clearance (CL) was 3.55 L/h and volume of distribution (V) was 18.8 L. No covariates were included in the final model. Monte Carlo simulations showed a low probability of target attainment (PTA, trough at steady state of ≥6 mg/L) with a standard dose of 500 mg twice daily. A dose of at least 1000 mg twice daily was required to achieve 80% PTA. Two subjects, both with subtherapeutic trough levels, developed early onset seizures.

CONCLUSION

Our study examined the population PK of levetiracetam in a critically ill neurosurgical population. We found that this population displayed higher clearance and required higher doses to achieve target levels.

Weight-Based Enoxaparin Achieves Adequate Anti-Xa Levels More Often in Trauma Patients: A Prospective Study

BACKGROUND

Previous research demonstrates that twice-daily enoxaparin is inadequate for venous thromboembolic (VTE) prophylaxis in critically ill trauma patients prompting dose adjustment based on anti-Xa levels. Most studies evaluate peak anti-Xa levels; however, data suggest that trough levels are associated with decreased VTE. We evaluated trough anti-Xa levels in noncritically ill trauma patients receiving fixed or weight-based enoxaparin.

METHODS

Peak and trough anti-Xa levels were prospectively collected from patients receiving at least 3 consecutive doses of enoxaparin (PRE). A performance improvement project prompted a change to weight-based dosing. Peak and trough levels were subsequently prospectively collected from the weight-based group (POST). Adequate peak was defined as ≥0.2 IU/mL and adequate trough as ≥0.1 IU/mL. PRE and POST groups were compared.

RESULTS

200 patients were evaluated (100 PRE, 100 POST). In the PRE group, only 34% of trough and 61% of peak anti-Xa levels were adequate compared with 82% and 97%, respectively, in the POST group (P < .01). Median trough improved from 0.07 IU/mL to 0.2 IU/mL (P < .01). Median peak improved from 0.22 IU/mL to 0.47 IU/mL (P < .01). More patients achieved adequate peak and trough levels in the POST group (79% vs 31%, P < .01). 95% of patients with adequate troughs also had adequate peaks, whereas 75% with adequate peaks had adequate troughs.

DISCUSSION

Traditional enoxaparin dosing in noncritically ill trauma patients results in suboptimal anti-Xa levels. Weight-based enoxaparin improves both trough and peak anti-Xa levels obviating dose adjustment. Furthermore, troughs better predict adequate anti-Xa levels.

Augmented Renal Clearance and How to Augment Antibiotic Dosing

Augmented renal clearance (ARC) refers to the state of heightened renal filtration commonly observed in the critically ill. Its prevalence in this patient population is a consequence of the body’s natural response to serious disease, as well as the administration of fluids and pharmacologic therapies necessary to maintain sufficient blood pressure. ARC is objectively defined as a creatinine clearance of more than 130 mL/min/1.73 m² and is thus a crucial condition to consider when administering antibiotics, many of which are cleared renally. Using conventional dosing regimens risks the possibility of subtherapeutic concentrations or clinical failure. Over the past decade, research has been conducted in patients with ARC who received a number of antibacterials frequently used in the critically ill, such as piperacillin-tazobactam or vancomycin. Strategies to contend with this condition have also been explored, though further investigations remain necessary.

A simple scoring method to predict augmented renal clearance in haematologic malignancies

WHAT IS KNOWN AND OBJECTIVE

Augmented renal clearance (ARC; hyperfiltration with over 130 mL/min/1.73 m² of creatinine clearance (CL_cr )) commonly occurs in critically ill patients. Recent reports indicate that ARC also occurs in haematologic malignancies. However, the risk factors for ARC in haematologic malignancies remain unknown, and there is no established method to predict ARC in haematologic malignancies. Our objective was to explore the risk factors for ARC retrospectively and develop a scoring method to predict ARC.

METHODS

A single-centre, retrospective, observational cohort study was conducted at the Sendai Medical Center (Sendai, Japan); 133 patients (April 2017-March 2019) and 41 patients (April-November 2019) with haematopoietic tumours who were administered vancomycin were enrolled in the analysis and validation cohorts, respectively. To define ARC, we calculated the vancomycin serum concentration when CL_cr  = 130 mL/min/1.73 m² using a one-compartment model. Patients with ARC were defined as those whose actual concentration of vancomycin remained lower than the calculated concentration. Using the analysis cohort, we explored risk factors of ARC and developed a scoring method to predict ARC in haematologic malignancies. The reproducibility of the scoring system was demonstrated using the validation cohort.

RESULTS AND DISCUSSION

Through multivariate analysis, young age (P < .001), leukaemia (P = .001) and low serum creatinine (P < .001) were identified as risk factors. According to this result, we established the ARC detection method: age ≤ 50 years = 3 points, 50 years < age ≤65 years = 1 point, leukaemia = 2 points, low SCr = 2 points; patients scoring ≥ 5 points represent the ARC high-risk group. Using this scoring system, we could detect ARC with a sensitivity and specificity of 60.0% and 89.7% in the analysis cohort and 90.0% and 90.9% in the validation cohort, respectively.

WHAT IS NEW AND CONCLUSION

Our scoring method could predict ARC in haematologic malignancies and is useful as a simple screening tool for ARC.

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.

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.

Increased β-Lactams dosing regimens improve clinical outcome in critically ill patients with augmented renal clearance treated for a first episode of hospital or ventilator-acquired pneumonia: a before and after study

Background

Augmented renal clearance (ARC) is recognized as a leading cause of β-lactam subexposure when conventional dosing regimens are used. The main objective was to compare the clinical outcome of ARC patients treated by conventional or increased β-lactam dosing regimens for a first episode of hospital or ventilator-acquired pneumonia (HAP-VAP).

Methods

In this single-center, retrospective study, every ARC patient treated by β-lactam for a first episode of HAP-VAP was included during two 15-month periods, before (Control period) and after (Treatment period) the modification of a local antibiotic therapy protocol. ARC was defined by a 24-h measured creatinine clearance ≥ 150 ml/min. The primary endpoint was defined as a therapeutic failure of the antimicrobial therapy or a HAP-VAP relapse within 28 days. Inverse probability of treatment weight (IPTW) was derived from a propensity score model. Cox proportional hazard models were used to evaluate the association between treatment period and clinical outcome.

Results

During the study period, 177 patients were included (control period, N = 88; treatment period, N = 89). Therapeutic failure or HAP-VAP relapse was significantly lower in the treatment period (10 vs. 23%, p = 0.019). The IPTW-adjusted hazard ratio of poor clinical outcome in the treatment period was 0.35 (95% CI 0.15–0.81), p = 0.014. No antibiotic side effect was reported during the treatment period.

Conclusions

Higher than licensed dosing regimens of β-lactams may be safe and effective in reducing the rate of therapeutic failure and HAP-VAP recurrence in critically ill augmented renal clearance (ARC) patients.

Incidence and Risk Factors Associated with Multi-Drug-Resistant Pathogens in a Critically Ill Trauma Population: A Retrospective Cohort Study

Background: Multi-drug resistance is considered a serious health threat particularly in the intensive care unit (ICU) setting. Studies evaluating multi-drug-resistant (MDR) pathogens in critically ill trauma patients are limited. The objectives were to describe the incidence of MDR, extensive-drug-resistant (XDR), and pan-drug-resistant (PDR) organism growth in ICU patients admitted with traumatic injuries and to identify any risk factors associated with MDR growth. Patients and Methods: This was a retrospective single-center cohort study of all ICU adult patients identified via the institution's trauma registry from January 1, 2016 to August 31, 2017. Patients were included if they had positive culture growth with susceptibility data taken during the index hospitalization. Patients were excluded if their cultures were drawn within 48 hours of emergency department triage. Study groups were defined based on the presence of at least one MDR pathogen during the index hospitalization. Results: A total of 2,578 charts were reviewed and 95 patients (mean age, 60 years; 66 males [69%]) with 201 total cultures were included. The majority of positive cultures were from respiratory (69%) and urinary (16%) sources. Of the 201 positive cultures, the majority of species identified was Enterobacteriaceae (47%), Staphylococcus (32%), Enterococcus (7%), Acinetobacter (5%), and Pseudomonas (3%). Of the 95 patients with positive cultures, the incidence of MDR, XDR, and PDR organisms was found to be 31%, 17%, and 0%, respectively. Augmented renal clearance (ARC) was the only risk factor associated with an increased risk for MDR organism growth (adjusted odds ratio 9.78, 95% confidence interval [CI] 2.56-37.41; p = 0.001). Conclusions: In this cohort of critically ill trauma patients, the incidence of an MDR pathogen occurred in 31% of patients. This is the first study to find an association of ARC and multi-drug resistance, which should be further validated as a potential cause for MDR organisms.

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.

Risk Factors and Clinical Outcomes Associated With Augmented Renal Clearance in Trauma Patients

BACKGROUND

Augmented renal clearance (ARC; i.e., creatinine clearance [CL_Cr] ≥ 130 mL/min) has an incidence of 14%-80% in critically ill patients and has been associated with therapy failures for renally cleared drugs. However, the clinical implications of ARC are poorly defined. We hypothesize that modifiable risk factors that contribute to ARC can be identified in severely injured trauma patients and that these risk factors influence clinical outcome.

METHODS

In 207 trauma intensive care unit patients, 24-h CL_Cr was correlated with clinical estimates of glomerular filtration rate (by Cockroft-Gault, modification of diet in renal disease, or chronic kidney disease epidemiology), and clinical outcomes (infection, venous thromboembolism [VTE], length of stay, and mortality).

RESULTS

The population was 45 ± 20 y, 68% male, 77% blunt injury with injury severity score of 24 (17-30). Admission serum creatinine was 1.02 ± 0.35 mg/dL, CL_Cr was 154 ± 77 mL/min, VTE incidence was 15%, ARC incidence was 57%, and mortality was 11%. Clinical estimates of glomerular filtration rate by Cockroft-Gault, modification of diet in renal disease, chronic kidney disease epidemiology underestimated actual CL_Cr by 20%, 22%, or 15% (all P < 0.01). CL_Cr was higher in males and those who survived, and lower in those with hypertension, diabetes, positive cultures, receiving transfusions, or pressors (all P < 0.05). On multivariate analysis, male gender (odds ratio [OR] 2.9 [1.4-6.1]), age (OR 0.97 [0.95-0.99]), and packed red blood cells transfusion (OR 0.31 [0.15-0.66]) were the only independent predictors of ARC.

CONCLUSIONS

ARC occurs in more than half of all high-risk trauma intensive care unit patients and is underestimated by standard clinical equations. ARC was not associated with increased incidence of VTE or infection but rather is associated with younger healthier males and reduced mortality. ARC seems to be a beneficial compensatory response to trauma.

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.

Augmented Renal Clearance

Augmented renal clearance (ARC) is a phenomenon in critically ill patients characterized by increased creatinine clearance and elimination of renally eliminated medications. Patients with severe neurologic injury, sepsis, trauma, and burns have been consistently identified as at risk of ARC, with mean creatinine clearances ranging from 170 ml/minute to more than 300 ml/minute. Several potential mechanisms may contribute to the occurrence of ARC including endogenous responses to increased metabolism and solute production, alterations in neurohormonal balance, and therapeutic maneuvers such as fluid resuscitation. Augmented renal clearance is associated with suboptimal exposure to critical medications, including β-lactams and vancomycin, increasing the risk of treatment failure. Although definitive screening tools are not yet known, critical care pharmacists must be vigilant in recognizing when ARC may be a contributing factor affecting expected treatment outcomes in individual patients. Optimizing dosing strategies in critically ill patients with ARC remains a goal of continued research. The current review discusses the clinical characteristics and methods of identifying patients at risk of ARC, potential mechanisms for ARC, and describes pharmacotherapy dosing considerations in patients with ARC.