Medication Dosing in Critically Ill Patients With Acute Kidney Injury Treated With Renal Replacement Therapy

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2024

The 2024 revised edition of the Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock (J-SSCG 2024) is published by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine. This is the fourth revision since the first edition was published in 2012. The purpose of the guidelines is to assist healthcare providers in making appropriate decisions in the treatment of sepsis and septic shock, leading to improved patient outcomes. We aimed to create guidelines that are easy to understand and use for physicians who recognize sepsis and provide initial management, specialized physicians who take over the treatment, and multidisciplinary healthcare providers, including nurses, physical therapists, clinical engineers, and pharmacists. The J-SSCG 2024 covers the following nine areas: diagnosis of sepsis and source control, antimicrobial therapy, initial resuscitation, blood purification, disseminated intravascular coagulation, adjunctive therapy, post-intensive care syndrome, patient and family care, and pediatrics. In these areas, we extracted 78 important clinical issues. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 42 GRADE-based recommendations, 7 good practice statements, and 22 information-to-background questions were created as responses to clinical questions. We also described 12 future research questions.

Antimicrobial dosing recommendations during continuous renal replacement therapy: different databases, different doses

Meticulous antimicrobial management is essential among critically ill patients with acute kidney injury, particularly if renal replacement therapy is needed. Many factors affect drug removal in patients undergoing continuous renal replacement therapy CRRT. In this study, we aimed to compare current databases that are frequently used to adjust CRRT dosages of antimicrobial drugs with the gold standard. The dosage recommendations from various databases for antimicrobial drugs eliminated by CRRT were investigated. The book 'Renal Pharmacotherapy: Dosage Adjustment of Medications Eliminated by the Kidneys' was chosen as the gold standard. There were variations in the databases. Micromedex, UpToDate, and Sanford had similar rates to the gold standard of 45%, 35%, and 30%, respectively. The Micromedex database shows the most similar results to the gold standard source. In addition, a consensus was reached as a result of the expert panel meetings established to discuss the different antimicrobial dose recommendations of the databases.

Electrolyte, acid-base, and medication management with renal replacement therapy

Fluid and electrolyte homeostasis exhibited by the kidneys is a complex process that is challenging to regulate with artificial renal replacement therapy (RRT). RRT has been used as a treatment modality for electrolyte and acid-base disturbances in patients with acute kidney injury and chronic kidney disease. This review highlights the management of electrolyte shifts, acid-base disturbances, and medication considerations in RRT, with a focus on intermittent hemodialysis and continuous RTT in the inpatient setting.

Antimicrobial safety considerations in critically ill patients: part I: focused on acute kidney injury

INTRODUCTION

Antibiotic prescription is a challenging issue in critical care settings. Different pharmacokinetic and pharmacodynamic properties, polypharmacy, drug interactions, and high incidence of multidrug-resistant microorganisms in this population can influence the selection, safety, and efficacy of prescribed antibiotics.

AREAS COVERED

In the current article, we searched PubMed, Scopus, and Google Scholar for estimating renal function in acute kidney injury, nephrotoxicity of commonly used antibiotics, and nephrotoxin stewardship in intensive care units.

EXPERT OPINION

Early estimation of kidney function with an accurate method may be helpful to optimize antimicrobial treatment in critically ill patients. Different antibiotic dosing regimens may be required for patients with acute kidney injury. In many low-resource settings, therapeutic drug monitoring is not available for antibiotics. Acute kidney injury may influence treatment effectiveness and patient outcome.

Correlation of antimicrobial fraction unbound and sieving coefficient in critically ill patients on continuous renal replacement therapy: a systematic review

Background

Fraction unbound has been used as a surrogate for antimicrobial sieving coefficient (SC) to predict extracorporeal clearance in critically ill patients on continuous renal replacement therapy (CRRT), but this is based largely on expert opinion.

Objectives

To examine relationships between package insert-derived fraction unbound (Fu-P), study-specific fraction unbound (Fu-S), and SC in critically ill patients receiving CRRT.

Methods

English-language studies containing patient-specific in vivo pharmacokinetic parameters for antimicrobials in critically ill patients requiring CRRT were included. The primary outcome included correlations between Fu-S, Fu-P, and SC. Secondary outcomes included correlations across protein binding quartiles, serum albumin, and predicted in-hospital mortality, and identification of predictors for SC through multivariable analysis.

Results

Eighty-nine studies including 32 antimicrobials were included for analysis. SC was moderately correlated to Fu-S (R2 = 0.55, P < 0.001) and Fu-P (R2 = 0.41, P < 0.001). SC was best correlated to Fu-S in first (<69%) and fourth (>92%) quartiles of fraction unbound and above median albumin concentrations of 24.5 g/L (R2 = 0.71, P = 0.07). Conversely, correlation was weaker in patients with mortality estimates greater than the median of 55% (R2 = 0.06, P = 0.84). SC and Fu-P were also best correlated in the first quartile of antimicrobial fraction unbound (R2 = 0.66, P < 0.001). Increasing Fu-P, flow rate, membrane surface area, and serum albumin, and decreasing physiologic charge significantly predicted increasing SC.

Conclusions

Fu-S and Fu-P were both reasonably correlated to SC. Caution should be taken when using Fu-S to calculate extracorporeal clearance in antimicrobials with 69%–92% fraction unbound or with >55% estimated in-hospital patient mortality. Fu-P may serve as a rudimentary surrogate for SC when Fu-S is unavailable.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members.As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Evaluation and Development of Vancomycin Dosing Schemes to Meet New AUC/MIC Targets in Intermittent Hemodialysis Using Monte Carlo Simulation Techniques

Published vancomycin dosing recommendations for patients receiving maintenance hemodialysis were not designed to meet newly recommended 24-hour area under the curve/minimum inhibitory concentration (AUC_24h /MIC) pharmacokinetic/pharmacodynamic targets. The aims of this study were to predict pharmacokinetic/pharmacodynamic target attainment rates with a commonly used vancomycin regimen and to design a new dosing scheme incorporating therapeutic drug monitoring (TDM) to maximize target attainment in patients receiving vancomycin and hemodialysis with high- or low-flux hemodialyzers. Vancomycin pharmacokinetic- and dialysis-specific parameters were incorporated into Monte Carlo simulations (MCS). A commonly used vancomycin regimen was modeled to determine its likelihood of attaining AUC_24h /MIC targets for 1 week of thrice-weekly hemodialysis treatments. MCS was then used to develop optimal initial vancomycin dosing for patients receiving intradialytic or postdialytic vancomycin administration with either high- or low-flux hemodialyzers. Finally, a new MCS model incorporating TDM was built to further optimize the probability of pharmacokinetic/pharmacodynamic target attainment. Traditional vancomycin dosing methods are unlikely to meet AUC_24h /MIC targets. Vancomycin doses necessary to attain AUC_24h /MIC targets are significantly influenced by hemodialyzer permeability and whether vancomycin is administered intradialytically or after hemodialysis. Depending on dialyzer type and whether vancomycin is administered during or after hemodialysis, loading doses of 25 to 35 mg/kg followed by maintenance doses of 7.5 to 15 mg/kg are necessary to reach minimum AUC_24h /MIC targets in 90% of virtual patients. For a 3-day interdialytic period, a 30% higher maintenance dose is required to maintain target attainment. Dosing based on a single vancomycin serum concentration obtained prior to the second dialysis session greatly enhances the probability of target attainment.

Pharmacologic optimization of antibiotics for Gram-negative infections

PURPOSE OF REVIEW

Antimicrobial resistance among Gram-negative organisms is a rapidly escalating global challenge. Pharmacologic dose optimization based on pharmacokinetic/pharmacodynamic principles is essential for managing Gram-negative infections. High-risk patient populations may receive nonoptimized antimicrobial dosing because pf physiologic changes in acute illness and/or medical interventions. The purpose of this review is to discuss opportunities for pharmacologic optimization of new agents and highlight patient populations that are often associated with poor drug exposure profiles.

RECENT FINDINGS

Dose optimization of the novel β-lactam-β-lactamase inhibitor combinations has been evaluated through optimizing exposure at the site of infection, evaluating target attainment of both the β-lactam and the β-lactamase-inhibitor in critically ill patients, and evaluating drug exposure to prevent the development of resistance. Plazomicin, a novel aminoglycoside, has pharmacodynamic optimization potential via therapeutic drug monitoring and nomogram-based dosing. Recent studies have evaluated the adequacy of dosing in varying degrees of renal function specifically acute kidney injury, continuous renal replacement therapy (CRRT), and augmented renal clearance (ARC).

SUMMARY

The application of fundamental pharmacokinetic/pharmacodynamic principles is required to optimize new antimicrobials in the treatment of serious Gram-negative infections. Exposure at the site of infection, pharmacokinetics in critically ill patients, and exposures to prevent resistance are all considerations to improve microbiologic and clinical outcomes. Therapeutic drug monitoring may be needed for high-risk patients.

Drug Dosing in Critically Ill Patients with Acute Kidney Injury and on Renal Replacement Therapy

Acute kidney injury (AKI) complicates in around 40-50% of patients in intensive care units (ICUs), and this can account for up to 80% mortality, especially in those patients requiring renal replacement therapy (RRT). Appropriate drug dosing in such patients is a challenge to the intensivists due to various factors such as patient related (appropriate body weight, organ clearance, serum protein concentration), drug related [molecular weight (MW), protein binding, volume of distribution (V d), hydrophilicity, or hydrophobicity], and RRT related (type, modality of solute removal, filter characteristics, dose, and duration). Therapeutic drug monitoring (TDM) of drugs can be a promising solution to this complex scenario to titrate a drug to its clinical response, but it is available only for a few drugs. In this review, we discussed drug dosing aspects of antimicrobials, sedatives, and antiepileptics in critically ill patients with AKI on RRT.

HOW TO CITE THIS ARTICLE

Saran S, Rao NS, Azim A. Drug Dosing in Critically Ill Patients with Acute Kidney Injury and on Renal Replacement Therapy. Indian J Crit Care Med 2020;24(Suppl 3):S129-S134.

Antibiotic Dosing for Critically Ill Adult Patients Receiving Intermittent Hemodialysis, Prolonged Intermittent Renal Replacement Therapy, and Continuous Renal Replacement Therapy: An Update

Objective: To summarize current antibiotic dosing recommendations in critically ill patients receiving intermittent hemodialysis (IHD), prolonged intermittent renal replacement therapy (PIRRT), and continuous renal replacement therapy (CRRT), including considerations for individualizing therapy. Data Sources: A literature search of PubMed from January 2008 to May 2019 was performed to identify English-language literature in which dosing recommendations were proposed for antibiotics commonly used in critically ill patients receiving IHD, PIRRT, or CRRT. Study Selection and Data Extraction: All pertinent reviews, selected studies, and references were evaluated to ensure appropriateness for inclusion. Data Synthesis: Updated empirical dosing considerations are proposed for antibiotics in critically ill patients receiving IHD, PIRRT, and CRRT with recommendations for individualizing therapy. Relevance to Patient Care and Clinical Practice: This review defines principles for assessing renal function, identifies RRT system properties affecting drug clearance and drug properties affecting clearance during RRT, outlines pharmacokinetic and pharmacodynamic dosing considerations, reviews pertinent updates in the literature, develops updated empirical dosing recommendations, and highlights important factors for individualizing therapy in critically ill patients. Conclusions: Appropriate antimicrobial selection and dosing are vital to improve clinical outcomes. Dosing recommendations should be applied cautiously with efforts to consider local epidemiology and resistance patterns, antibiotic dosing and infusion strategies, renal replacement modalities, patient-specific considerations, severity of illness, residual renal function, comorbidities, and patient response to therapy. Recommendations provided herein are intended to serve as a guide in developing and revising therapy plans individualized to meet a patient's needs.

A Guide to Understanding Antimicrobial Drug Dosing in Critically Ill Patients on Renal Replacement Therapy

A careful management of antimicrobials is essential in the critically ill with acute kidney injury, especially if renal replacement therapy is required. Acute kidney injury may lead per se to clinically significant modifications of drugs' pharmacokinetic parameters, and the need for renal replacement therapy represents a further variable that should be considered to avoid inappropriate antimicrobial therapy. The most important pharmacokinetic parameters, useful to determine the significance of extracorporeal removal of a given drug, are molecular weight, protein binding, and distribution volume. In many cases, the extracorporeal removal of antimicrobials can be relevant, with a consistent risk of underdosing-related treatment failure and/or potential onset of bacterial resistance. It should also be taken into account that renal replacement therapies are often not standardized in critically ill patients, and their impact on plasma drug concentrations may substantially vary in relation to membrane characteristics, treatment modality, and delivered dialysis dose. Thus, in this clinical scenario, the knowledge of the pharmacokinetic and pharmacodynamic properties of different antimicrobial classes is crucial to tailor maintenance dose and/or time interval according to clinical needs. Finally, especially for antimicrobials known for a tight therapeutic range, therapeutic drug monitoring is strongly suggested to guide dosing adjustment in complex clinical settings, such as septic patients with acute kidney injury undergoing renal replacement therapy.

Pharmacokinetics-pharmacodynamics issues relevant for the clinical use of beta-lactam antibiotics in critically ill patients

Antimicrobials are among the most important and commonly prescribed drugs in the management of critically ill patients and beta-lactams are the most common antibiotic class used. Critically ill patient's pathophysiological factors lead to altered pharmacokinetics and pharmacodynamics of beta-lactams.A comprehensive bibliographic search in PubMed database of all English language articles published from January 2000 to December 2017 was performed, allowing the selection of articles addressing the pharmacokinetics or pharmacodynamics of beta-lactam antibiotics in critically ill patients.In critically ill patients, several factors may increase volume of distribution and enhance renal clearance, inducing high intra- and inter-patient variability in beta-lactam concentration and promoting the risk of antibiotic underdosing. The duration of infusion of beta-lactams has been shown to influence the fT > minimal inhibitory concentration and an improved beta-lactam pharmacodynamics profile may be obtained by longer exposure with more frequent dosing, extended infusions, or continuous infusions.The use of extracorporeal support techniques in the critically ill may further contribute to this problem and we recommend not reducing standard antibiotic dosage since no drug accumulation was found in the available literature and to maintain continuous or prolonged infusion, especially for the treatment of infections caused by multidrug-resistant bacteria.Prediction of outcome based on concentrations in plasma results in overestimation of antimicrobial activity at the site of infection, namely in cerebrospinal fluid and the lung. Therefore, although no studies have assessed clinical outcome, we recommend using higher than standard dosing, preferably with continuous or prolonged infusions, especially when treating less susceptible bacterial strains at these sites, as the pharmacodynamics profile may improve with no apparent increase in toxicity.A therapeutic drug monitoring-guided approach could be particularly useful in critically ill patients in whom achieving target concentrations is more difficult, such as obese patients, immunocompromised patients, those infected by highly resistant bacterial strains, patients with augmented renal clearance, and those undergoing extracorporeal support techniques.

Inadequate antibiotic dosing in patients receiving sustained low efficiency dialysis

Background Patients requiring SLED are often critically ill and/or hemodynamically unstable, and often need antibiotic therapy for life-threatening infections. Antibiotic dosing recommendations for intermittent hemodialysis and continuous renal replacement therapy are not appropriate for SLED and there is substantial concern for under dosing. Objective To characterize the adequacy of antibiotic dosing during SLED. Setting: Inpatient adult acute care hospital. Methods A retrospective chart review was performed for the period of October 2010 to August 2013 to identify patients who received SLED and at least one of the selected antibiotics: cefepime, daptomycin, piperacillin/tazobactam, meropenem, and vancomycin. Dosing regimens were evaluated each day the patient was receiving one of these antibiotics concurrently with SLED. The administered antibiotic dosing regimens were defined as "adequate" or "inadequate" based on recommendations available in the literature. Main outcome measure The percentage of adequate antibiotic days for each antibiotic. Results Antibiotic regimens were evaluated for a total of 51 patients: 35 (69%) with acute kidney injury, 16 (31%) with end-stage renal disease, mean SLED duration 9.3 ± 1.7 h. The total percent of adequate antibiotic days were: vancomycin 86%, cefepime 62%, daptomycin 58%, meropenem 35%, and piperacillin/tazobactam 20%. Under dosing accounted for 63% of the days antibiotic dosing was considered inadequate. Conclusion: Antibiotic dosing was frequently inadequate, especially for antibiotics requiring more frequent dosing, suggesting a high potential for subtherapeutic levels during the majority of time critically ill patients are requiring SLED.

A Monte Carlo Simulation Approach for Beta-Lactam Dosing in Critically Ill Patients Receiving Prolonged Intermittent Renal Replacement Therapy

Cefepime, ceftazidime, and piperacillin/tazobactam are commonly used beta-lactam antibiotics in the critical care setting. For critically ill patients receiving prolonged intermittent renal replacement therapy (PIRRT), limited pharmacokinetic data are available to inform clinicians on the dosing of these agents. Monte Carlo simulations (MCS) can be used to guide drug dosing when pharmacokinetic trials are not feasible. For each antibiotic, MCS using previously published pharmacokinetic data derived from critically ill patients was used to evaluate multiple dosing regimens in 4 different prolonged intermittent renal replacement therapy effluent rates and prolonged intermittent renal replacement therapy duration combinations (4 L/h × 10 hours or 5 L/h × 8 hours in hemodialysis and hemofiltration modes). Antibiotic regimens were also modeled depending on whether drugs were administered during or well before prolonged intermittent renal replacement therapy therapy commenced. The probability of target attainment (PTA) was calculated using each antibiotic's pharmacodynamic target during the first 48 hours of therapy. Optimal doses were defined as the smallest daily dose achieving ≥90% probability of target attainment in all prolonged intermittent renal replacement therapy effluent and duration combinations. Cefepime 1 g every 6 hours following a 2 g loading dose, ceftazidime 2 g every 12 hours, and piperacillin/tazobactam 4.5 g every 6 hours attained the desired pharmacodynamic target in ≥90% of modeled prolonged intermittent renal replacement therapy patients. Alternatively, if an every 6-hours cefepime regimen is not desired, the cefepime 2 g pre-prolonged intermittent renal replacement therapy and 3 g post-prolonged intermittent renal replacement therapy regimen also met targets. For ceftazidime, 1 g every 6 hours or 3 g continuous infusion following a 2 g loading dose also met targets. These recommended doses provide simple regimens that are likely to achieve the pharmacodynamics target while yielding the least overall drug exposure, which should result in lower toxicity rates. These findings should be validated in the clinical setting.

Acetaminophen clearance during ex vivo continuous renal replacement therapies

Intravenous acetaminophen is an adjuvant to opioid use in critically ill and surgical patients requiring continuous renal replacement therapy (CRRT). The objective of this study was to determine the ex vivo transmembrane clearance of intravenous acetaminophen during continuous hemofiltration and hemodialysis. Transmembrane clearance was assessed using a validated ex vivo bovine blood model for CRRT using an F8 or HF1400 hemodiafilter. Ultrafiltrate and dialysate flow rates were 1, 2, and 3 L/h. Urea and acetaminophen clearances were calculated and compared. Acetaminophen was readily cleared by continuous hemofiltration with both hemodiafilters. Acetaminophen clearance rates were 92-98% of ultrafiltrate production rates. Similarly, dialytic acetaminophen clearances approximated dialysate flow rates for both hemodiafilters. Acetaminophen is readily cleared by CRRT. Patients receiving CRRT and acetaminophen may require increased doses for adequate pain control.

Renal Replacement Therapy in Acute Kidney Injury: Controversies and Consensus

Acute kidney injury (AKI) is a common complication among critically ill patents, and 5% of intensive care unit (ICU) patients require initiation of renal replacement therapy (RRT). In recent years, clinical trials have provided evidence-based guidance for some important aspects of RRT management in patients with AKI, such as dialysis dosing and approaches to anticoagulation in patients undergoing continuous RRT. However, there remain many areas of uncertainty, and delivery of RRT in the ICU requires clinical judgment, flexibility, and an understanding of dialysis principles. This article reviews the components of RRT prescription and provides an update on best practices.

Survey of pharmacists’ antibiotic dosing recommendations for sustained low-efficiency dialysis

BACKGROUND

The use of hybrid renal replacement therapies like sustained low efficiency dialysis (SLED) is increasing in ICUs worldwide. However, pharmacokinetic studies designed to inform therapeutic antibiotic dosing in critically ill patients receiving SLED are limited. SLED operational characteristics vary across institutions. Pharmacists in institutions that utilize SLED are challenged to recommend therapeutic doses for antibiotics.

OBJECTIVE

To characterize pharmacist-recommended antibiotic regimens for SLED.

METHODS

An electronic survey was sent to pharmacist members of the American College of Clinical Pharmacy in the Nephrology or Critical Care Practice and Research Network. Dosing recommendations for a hypothetical critically ill septic patient were collected for cefepime, ceftaroline, daptomycin, levofloxacin, meropenem, and piperacillin/tazobactam. Main outcome measure Antibiotic regimens for the six antibiotics, their frequency, pharmacist’s experience with renal replacement therapies (RRT), post-graduate training, years of clinical experience, number of staffed beds in their hospital, and RRT employed in their ICUs.

RESULTS

The survey was completed by 69 clinical pharmacists who had 8.5 ± 7.5 (mean ± SD) years of experience. All pharmacists had experience dosing medications for patients receiving RRT. The most frequently recommended regimen for each antibiotic was: cefepime 1000 mg every 24 h, ceftaroline 200 mg every 12 h, daptomycin 6 mg/kg every 24 h, levofloxacin 500 mg every 24 h, meropenem 1000 mg every 12 h, and piperacillin/tazobactam 2250 mg every 8 h. Up to nine distinct regimens were recommended for each antibiotic, and the total daily dose between these regimens ranged by as much as a 12-fold. Neither pharmacist’s experience with SLED, post-graduate training, nor years of clinical experience were significantly associated with particular dosing recommendations for the antibiotics.

CONCLUSION

Pharmacists working in institutions that utilize SLED make antibiotic dosing recommendations that vary 4–12-fold depending on the drug. Published research does not provide adequate guidance to optimally dose antibiotics in patients receiving SLED. More SLED pharmacokinetic trials, real-time serum concentration monitoring and advanced pharmacokinetic modeling techniques are necessary to ensure therapeutic dosing in patients receiving SLED.

Pharmacokinetics and pharmacodynamics of antibiotics in critically ill acute kidney injury patients

Sepsis is the most common cause of death in critically ill patients and is associated with multiorgan failure, including acute kidney injury (AKI). This situation can require acute renal support and increase mortality. Therefore, it is essential to administer antimicrobials in doses that achieve adequate serum levels, avoiding both overdosing and drug toxicity as well as underdosing and the risk of antibiotic resistance and higher mortality. Currently, there are no validated guidelines on antibiotic dose adjustments in septic patients with AKI. The current recommendations were extrapolated from studies conducted in noncritical patients with end‐stage chronic kidney disease receiving chronic renal replacement therapy. This study aimed to review and discuss the complexity of this issue, considering several factors related to drug metabolism, the characteristics of critically ill patients, the properties of antimicrobial drugs and dialysis methods.

Prolonged Intermittent Renal Replacement Therapy

Prolonged intermittent renal replacement therapy (PIRRT) is becoming an increasingly popular alternative to continuous renal replacement therapy in critically ill patients with acute kidney injury. There are significant practice variations in the provision of PIRRT across institutions, with respect to prescription, technology, and delivery of therapy. Clinical trials have generally demonstrated that PIRRT is non-inferior to continuous renal replacement therapy regarding patient outcomes. PIRRT offers cost-effective renal replacement therapy along with other advantages such as early patient mobilization and decreased nursing time. However, due to lack of standardization of the procedure, PIRRT still poses significant challenges, especially pertaining to appropriate drug dosing. Future guidelines and clinical trials should work toward developing consensus definitions for PIRRT and ensure optimal delivery of therapy.

We Underdose Antibiotics in Patients on CRRT

Appropriate antibiotic dosing in critically ill, infected, patients receiving continuous renal replacement therapy (CRRT) is crucial to improve patient outcomes. Severe sepsis and septic shock result in changes in pharmacokinetic parameters, including increased volume of distribution, hypoalbuminemia, and changes in renal and nonrenal clearances. The lack of CRRT standardization, nonrecognition of how CRRT variability affects antibiotic removal, fear of antibiotic toxicity, and limited drug dosing resources all contribute to suboptimal antibiotic therapy. Even when antibiotic CRRT pharmacokinetic studies are available, they are often based on old CRRT methodologies that do not exist in contemporary CRRT practice, resulting in unhelpful/inaccurate dosing recommendations. Application of these older doses in Monte Carlo simulation studies reveals that many of the recommended dosing regimens will never attain pharmacodynamic targets. In this review, using cefepime as an example, we illustrate whether clinicians are likely to achieve pharmacokinetic/pharmacodynamic targets when the recommended dosing regimens are prescribed in this patient population. We encourage clinicians to aggressively dose antibiotics with large loading dose and higher maintenance doses to reach the targets.

Antibiotic Dosing in Patients With Acute Kidney Injury: "Enough But Not Too Much"

Increasing evidence suggests that antibiotic dosing in critically ill patients with acute kidney injury (AKI) often does not achieve pharmacodynamic goals, and the continued high mortality rate due to infectious causes appears to confirm these findings. Although there are compelling reasons why clinicians should use more aggressive antibiotic dosing, particularly in patients receiving aggressive renal replacement therapies, concerns for toxicity associated with higher doses are real. The presence of multisystem organ failure and polypharmacy predispose these patients to drug toxicity. This article examines the pharmacokinetic and pharmacodynamic consequences of critical illness, AKI, and renal replacement therapy and describes potential solutions to help clinicians give "enough but not too much" in these very complicated patients.

Evolving practices in critical care and their influence on acute kidney injury

PURPOSE OF REVIEW

This review highlights the principal advances in critical care over the past year, and discusses the impact of these advances on the diagnosis and management of acute kidney injury (AKI).

RECENT FINDINGS

Recent literature has focused on assessment of volume status and fluid management, particularly in the setting of respiratory and cardiac failure. Other critical care topics are reviewed using a system-based approach.

SUMMARY

The incidence of AKI appears to be increasing, and despite advances in the provision of critical care and renal replacement therapies, there has been little improvement in its associated morbidity and mortality. Nonetheless, recent advances in critical care will impact the diagnosis and management of AKI, as well as shape the future research agenda. Continued work in the fields of critical care and nephrology will undoubtedly be centered on improved biomarkers for the detection of AKI, specific therapies to mitigate or reverse AKI, and techniques to prevent the development of AKI in the critically ill population.

Population pharmacokinetics and dose simulation of vancomycin in critically ill patients during high-volume haemofiltration

This study aimed to describe the population pharmacokinetics of vancomycin in critically ill patients with refractory septic shock undergoing continuous venovenous high-volume haemofiltration (HVHF) and to define appropriate dosing for these patients. This was a prospective pharmacokinetic study in the ICU of a university hospital. Eight blood samples were taken over one vancomycin dosing interval. Samples were analysed by a validated liquid chromatography-tandem mass spectrometry assay. Non-linear mixed-effects modelling was used to describe the population pharmacokinetics. Dosing simulations were used to define therapeutic vancomycin doses for different HVHF settings. Nine patients were included (five male). The mean weight and SOFA score were 70 kg and 11, respectively. Mean HVHF settings were: blood flow rate, 240 mL/min; and haemofiltration exchange rate, 100 mL/kg/h. A linear two-compartment model with zero-order input adequately described the data. Mean parameter estimates were: clearance, 2.9 L/h; volume of distribution of central compartment (V(1)), 11.8L; volume of distribution of peripheral compartment (V(2)), 18.0 L; and intercompartmental clearance, 9.3 L/h. HVHF intensity was strongly associated with vancomycin clearance (P < 0.05) and was a covariate in the final model. Simulations indicate that after a loading dose, vancomycin doses required for different HVHF intensities would be 750 mg every 12h (q12h) for 69 mL/kg/h, 1000 mg q12h for 100 mL/kg/h and 1500 mg q12h for 123 mL/kg/h. Continuous infusion would also be a valuable administration strategy. In conclusion, variable and much higher than standard vancomycin doses are required to achieve therapeutic concentrations during different HVHF settings.