Pharmacokinetics of meropenem in children with sepsis undergoing extracorporeal life support: A prospective observational study

The impact of extracorporeal support on antimicrobial pharmacokinetics in critically ill neonatal and paediatric patients: A systematic review

OBJECTIVES

Infections represent a major risk for critically ill neonatal and paediatric patients requiring extracorporeal life-saving support such as extracorporeal membrane oxygenation (ECMO) and/or continuous renal replacement therapies (CRRT). Patient outcomes rely on achieving target antimicrobial concentrations. In critically ill adults on extracorporeal support, suboptimal antimicrobial concentrations have been shown to be common. Our objective was to systematically review antimicrobial pharmacokinetic studies in critically ill term neonatal and paediatric patients receiving ECMO and/or CRRT and compare them to similar cohorts of patients not receiving ECMO or CRRT.

METHODS

Studies published between 1990 and 2022 were identified through systematic searches in PUBMED, Embase, Web of Science, Medline, Google Scholar and CINAHL. Studies were included which provided antimicrobial pharmacokinetic parameters (volume of distribution and clearance) in the neonatal and paediatric patients receiving ECMO and/or CRRT. Studies were excluded if no antimicrobial pharmacokinetic parameters were described or could be calculated.

RESULTS

Forty-four pharmacokinetic studies were identified describing 737 patients, with neonatal patients recruited in 70% of the ECMO studies and <1% of the CRRT studies. Of all the studies, 50% were case reports or case series. The pharmacokinetics were altered for gentamicin, daptomycin, ceftolozane, micafungin, voriconazole, cefepime, fluconazole, piperacillin, and vancomycin, although considerable patient variability was described.

CONCLUSION

Significant gaps remain in our understanding of the pharmacokinetic alterations in neonatal and paediatric patients receiving ECMO and CRRT support.

Optimizing the connection of CRRT and ECMO lines with additional pressure regulator on the therapeutic effect, filter life, and incidence of complications

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is used for severe cardiopulmonary failure, with veno-arterial ECMO for cardiogenic shock and veno-venous ECMO for acute respiratory failure. ECMO's application has expanded to ICUs, emergency departments, and operating rooms. ECMO patients are at high risk for complications, including acute kidney injury (AKI), often requiring renal replacement therapy (RRT), posing significant management challenges.

METHODS

From August 2015 to June 2022, 120 patients were cured with veno-venous ECMO (n = 60) or veno-arterial ECMO (VA-ECMO, n = 60) combined with CRRT in our hospital. In the control group (n = 60), the input end (arterial end) of CRRT was connected to the ECMO oxygenator. The reinfusion end (venous end) of CRRT was connected to the oxygenator of ECMO for CRRT + ECMO treatment. In the experimental group (n = 60), the input end (arterial end) of CRRT was connected to the oxygenator of ECMO, and an additional pressure regulating device was installed on the connection of the 2 lines. The observation indexes including clinical therapeutic effect, clinical therapeutic effect, the incidence of complications, and the incidence of complications were compared.

RESULTS

There was a notable decrease in serum creatinine, and the differences in blood urea nitrogen, procalcitonin, and C-reactive protein after operation were statistically significant (P < .05). The filter use time in the study group was notably longer (P < .01). There exhibited no remarkable difference in the incidences of bleeding, thrombosis, numbness of hands and feet, metabolic alkalosis, disseminated intravascular coagulation, organ dysfunction syndrome, hyperbilirubinemia, and infection.

CONCLUSION

This study demonstrates that additional pressure regulation devices are installed at the line connection between the CRRT input end and the CRRT return end to ensure that the flow rate of ECMO does not affect the CRRT treatment. ECMO and CRRT provide a safe pressure range so that the ECMO line can be safely connected to the CRRT machine at physiological pressure, reducing the occurrence of complications related to CRRT machine interruption and improving the efficiency of CRRT without affecting the efficiency of ECMO, ensuring patient safety.

Meropenem Disposition in Neonatal and Pediatric Extracorporeal Membrane Oxygenation and Continuous Renal Replacement Therapy

This study aimed to characterize the impact of extracorporeal membrane oxygenation (ECMO) on the pharmacokinetics (PK) of meropenem in neonates and children and to provide recommendations for meropenem dosing in this specific population of patients. Therapeutic drug monitoring (152 meropenem plasma concentrations) data from 45 patients (38 received ECMO) with a body weight (BW) of 7.88 (3.62-11.97) kg (median (interquartile range)) and postnatal age of 3 (0-465) days were collected. The population PK analysis was performed using NONMEM V7.3.0. Monte Carlo simulations were performed to assess the probability of target achievement (PTA) for 40% of time the free drug remained above the minimum inhibitory concentration (fT > MIC) and 100% fT > MIC. BW was found to be a significant covariate for the volume of distribution (Vd) and clearance (CL). Additionally, continuous renal replacement therapy (CRRT) was associated with a two-fold increase in Vd. In the final model, the CL and Vd for a typical patient with a median BW of 7.88 kg that was off CRRT were 1.09 L/h (RSE = 8%) and 3.98 L (14%), respectively. ECMO did not affect meropenem PK, while superimposed CRRT significantly increased Vd. We concluded that current dosing regimens provide acceptably high PTA for MIC ≤ 4 mg/L for 40% fT > MIC, but individual dose adjustments are needed for 100% fT > MIC.

How to use meropenem in pediatric patients undergoing CKRT? Integrated meropenem pharmacokinetic model for critically ill children

Standard dosing could fail to achieve adequate systemic concentrations in ICU children or may lead to toxicity in children with acute kidney injury. The population pharmacokinetic analysis was used to simultaneously analyze all available data (plasma, prefilter, postfilter, effluent, and urine concentrations) and provide the pharmacokinetic characteristics of meropenem. The probability of target fT > MIC attainment, avoiding toxic levels, during the entire dosing interval was estimated by simulation of different intermittent and continuous infusions in the studied population. A total of 16 critically ill children treated with meropenem were included, with 7 of them undergoing continuous kidney replacement therapy (CKRT). Only 33% of children without CKRT achieved 90% of the time when the free drug concentration exceeded the minimum inhibitory concentration (%fT > MIC) for an MIC of 2 mg/L. In dose simulations, only continuous infusions (60-120 mg/kg in a 24-h infusion) reached the objective in patients <30 kg. In patients undergoing CKRT, the currently used schedule (40 mg/kg/12 h from day 2 in a short infusion of 30 min) was clearly insufficient in patients <30 kg. Keeping the dose to 40 mg/kg q8h without applying renal adjustment and extended infusions (40 mg/kg in 3- or 4-h infusion every 12 h) was sufficient to reach 90% fT > MIC (>2 mg/L) in patients >10 kg. In patients <10 kg, only continuous infusions reached the objective. In patients >30 kg, 60 mg/kg in a 24-h infusion is sufficient and avoids toxicity. This population model could help with an individualized dosing approach that needs to be adopted in critically ill pediatric patients. Critically ill patients subjected to or not to CKRT may benefit from the administration of meropenem in an extended or continuous infusion.

Meropenem Clearance in a Child With End-stage Renal Disease Undergoing Prolonged Intermittent Renal Replacement Therapy: A Case Report and Literature Review

BACKGROUND

Meropenem is frequently used to treat severe infections in critically ill children. However, pharmacokinetic data on meropenem in children with end-stage renal disease (ESRD) undergoing prolonged intermittent renal replacement therapy (PIRRT) is limited. Our objectives were to evaluate meropenem clearance in a child with ESRD with and without PIRRT, compare the results to previous continuous renal replacement therapy studies in children, toddlers and neonates, and assess whether the currently used dose of meropenem is sufficient.

CASE DESCRIPTION

A 5-year-old girl with an estimated glomerular filtration rate of 12.8 mL/min/1.73 m 2 was diagnosed with pulmonary infection and treated with 300 mg meropenem once a day. PIRRT was performed for 8 hours every 2 days. We used WinNonlin to evaluate meropenem clearance with and without PIRRT.

RESULTS

Our case showed that PIRRT increased the clearance of meropenem from 1.39 (1.3) to 2.42 L/h (2.3 mL/kg/min) and caught up 42.6% of the total clearance. This result is in accordance with previous studies in children but slightly less than seen in toddlers and neonates under continuous renal replacement therapy. The current dose of 300 mg once a day is not sufficient to reach the therapeutic target.

CONCLUSIONS

Predicting meropenem clearance in children with ESRD undergoing PIRRT is difficult as clearance will be affected by renal function, PIRRT settings and other factors. Further studies are needed to explore the individual variability of meropenem clearance and optimize the dosing regimen.

β-lactam precision dosing in critically ill children: Current state and knowledge gaps

There has been emerging interest in implementing therapeutic drug monitoring and model-informed precision dosing of β-lactam antibiotics in critically ill patients, including children. Despite a position paper endorsed by multiple international societies that support these efforts in critically ill adults, implementation of β-lactam precision dosing has not been widely adopted. In this review, we highlight what is known about β-lactam antibiotic pharmacokinetics and pharmacodynamics in critically ill children. We also define the knowledge gaps that present barriers to acceptance and implementation of precision dosing of β-lactam antibiotics in critically ill children: a lack of consensus on which subpopulations would benefit most from precision dosing and the uncertainty of how precision dosing changes outcomes. We conclude with opportunities for further research to close these knowledge gaps.

Individual Meropenem Clearance in Infants on ECMO and CVVHDF is Difficult to Predict: A Case Report and Review of the Literature

OBJECTIVES

Meropenem is a broad-spectrum carbapenem antibiotic with mostly renal excretion. Conflicting data are available regarding meropenem pharmacokinetics in critically ill neonates on concomitant continuous renal replacement therapy (CRRT) and/or extracorporeal membrane oxygenation (ECMO). Our objectives were to assess meropenem clearance in a neonate on CRRT and ECMO, compare it to previously published data and assess whether dose recommendations can be generalized in this population.

CASE DESCRIPTION

A 2.5 kg male infant with a large diaphragmatic hernia was delivered by cesarean section at week 35 and immediately mechanically ventilated due to shock and respiratory insufficiency. He underwent surgical correction of the hernia, but developed recurrent sepsis, multiorgan failure and pulmonary hypertension. He remained mechanically ventilated and required ECMO and continuous venovenous hemodiafiltration. He was started on meropenem 40 mg/kg/dose, every 8 hs for Enterobacter cloacae bacteremia and sepsis, but due to lack of clinical and microbiologic response despite in vitro susceptibility, he was started on a continuous meropenem infusion of 240 mg/kg/d, based on dose recommendations in a similar case. We measured steady state meropenem plasma concentrations on 2 occasions, during ECMO and continuous venovenous hemodiafiltration (CVVHDF) and then on CVVHDF only.

RESULTS

Meropenem serum concentrations were 90 and 64 mg/L on the first and second occasion (therapeutic target concentration, 10 mg/L) corresponding to a clearance of 1.9 and 2.6 mL/kg/min. This clearance estimate was substantially lower than that reported in toddlers on CRRT and ECMO in some studies.

CONCLUSION

In neonates and infants, meropenem clearance is difficult to predict because of dynamic ontogenetic changes in renal function. This problem is further aggravated in acutely ill infants with decreased renal function, renal replacement therapy and/or ECMO. Therefore, Target Concentration Intervention based on meropenem plasma concentrations is indispensable to ensure therapeutic exposure in this population.

Pharmacokinetics of Commonly Used Medications in Children Receiving Continuous Renal Replacement Therapy: A Systematic Review of Current Literature

BACKGROUND AND OBJECTIVE

The use of continuous renal replacement therapy (CRRT) for renal support has increased substantially in critically ill children compared with intermittent modalities owing to its preferential effects on hemodynamic stability. With the expanding role of CRRT, the quantification of extracorporeal clearance and the effect on primary pharmacokinetic parameters is of the utmost importance. Within this review, we aimed to summarize the current state of the literature and compare published pharmacokinetic analyses of commonly used medications in children receiving CRRT to those who are not.

METHODS

A systematic search of the literature within electronic databases PubMed, EMBASE, Cochrane Library, and Web of Science was conducted. Published studies that were included contained relevant information on the use of commonly administered medications to children, from neonates to adolescents, receiving CRRT. Pharmacokinetic parameters that were analyzed included volume of distribution, total clearance, extracorporeal clearance, area under the curve, and elimination half-life. Information regarding CRRT circuit, flow rates, and membrane components was analyzed to investigate differences in pharmacokinetics between each modality.

RESULTS

Forty-five studies met the final inclusion criteria within this systematic review, totaling 833 pediatric patients, with 586 receiving CRRT. Antimicrobials were the most common pharmacological class represented within the literature, representing 81% (35/43) of studies analyzed. Children receiving CRRT largely had similar volume of distribution and total clearance to critically ill children not receiving CRRT, suggesting reno-protective dose adjustments may lead to subtherapeutic dosing regimens in these patients. Overall, there was a tendency for hydrophilic agents, with a low protein binding to undergo elevated total clearance in these children. However, results should be interpreted with caution because of the large variability amongst patient populations and heterogeneity with CRRT modalities, flow rates, and use of extracorporeal membrane oxygenation within studies. This review was able to identify that variation in solute removal, or CRRT modalities, properties (i.e., flow rates), and membrane composition, may have differing effects on the pharmacokinetics of commonly administered medications.

CONCLUSIONS

The current state of the literature regarding medications administered to children receiving CRRT largely focuses on antimicrobials. Significant gaps remain with other commonly used medications such as sedatives and analgesics. Overall reporting of patient clinical characteristics, CRRT settings, and circuit composition was poor, with only 10% of articles including all relevant information to assess the impact of CRRT on total clearance. Changes in pharmacokinetics because of CRRT often required higher than labeled doses, suggesting renally adjusted or reno-protective doses may lead to subtherapeutic dosing regimens. A thorough understanding of the interplay between patient, drug, and CRRT-circuit factors are required to ensure adequate delivery of dosing regimens to this vulnerable population.

Antimicrobial Dosing Recommendations in Pediatric Continuous Renal Replacement Therapy: A Critical Appraisal of Current Evidence

OBJECTIVES

Continuous renal replacement therapy (CRRT) is commonly employed in critically ill children and is known to affect antimicrobial pharmacokinetics. There is a lack of readily available, evidence-based antimicrobial dosing recommendations in pediatric CRRT. This study aims to quantify commonly used antimicrobial drugs in pediatric CRRT and identify gaps between contemporary literature-based dosing recommendations and those presented in a frequently used dosing reference.

METHODS

The Pediatric Health Information System (PHIS) database was queried from July 1, 2018 through June 30, 2021 to identify admissions in which antimicrobials were billed on the same day as CRRT. Drugs of interest were selected if at least 10% of admission involved administration on at least one CRRT day, with additional clinically important antimicrobials selected by the authors. A comprehensive literature search was performed to identify antimicrobial pharmacokinetic (PK) studies in children for each selected drug. For identified articles, dosing recommendations were extracted and compared to those in a popular tertiary dosing reference (Lexi-Comp Online database). The level of agreement of the dosing recommendations was assessed.

RESULTS

77 unique antimicrobial agents were identified amongst 812 admissions from 20 different PHIS hospitals. Fifteen antimicrobials were billed on the same day as CRRT in ≥10% of admissions, with 4 additional drugs deemed clinically relevant by the authors. Twenty PK studies were identified for these 19 drugs, and dosing recommendations were included in 8 (42.1%) of them. Seventeen agents (89.5%) had some type of CRRT-specific dosing guidance in Lexi-Comp, with only 1 directly based on a pediatric CRRT study. For the 8 agents with PK data available, Lexi-Comp recommendations matched primary literature dosing guidance in 3 (37.5%). Two (25%) lacked agreement between the Lexi-Comp and primary literature, and the remaining 3 (37.5%) had partial agreement with multiple dosing regimens suggested in the primary literature and at least one of these regimens recommended by Lexi-Comp.

CONCLUSION

Significant gaps exist in the data supporting antimicrobial dosing recommendations for children receiving CRRT. Future studies should focus on antimicrobial dosing in pediatric CRRT, emphasizing provision of robust data from which dosing recommendations can be promptly incorporated into tertiary dosing references.

Pharmacokinetics of Antibiotics in Pediatric Intensive Care: Fostering Variability to Attain Precision Medicine

Children show important developmental and maturational changes, which may contribute greatly to pharmacokinetic (PK) variability observed in pediatric patients. These PK alterations are further enhanced by disease-related, non-maturational factors. Specific to the intensive care setting, such factors include critical illness, inflammatory status, augmented renal clearance (ARC), as well as therapeutic interventions (e.g., extracorporeal organ support systems or whole-body hypothermia [WBH]). This narrative review illustrates the relevance of both maturational and non-maturational changes in absorption, distribution, metabolism, and excretion (ADME) applied to antibiotics. It hereby provides a focused assessment of the available literature on the impact of critical illness—in general, and in specific subpopulations (ARC, extracorporeal organ support systems, WBH)—on PK and potential underexposure in children and neonates. Overall, literature discussing antibiotic PK alterations in pediatric intensive care is scarce. Most studies describe antibiotics commonly monitored in clinical practice such as vancomycin and aminoglycosides. Because of the large PK variability, therapeutic drug monitoring, further extended to other antibiotics, and integration of model-informed precision dosing in clinical practice are suggested to optimise antibiotic dose and exposure in each newborn, infant, or child during intensive care.

Population Pharmacokinetics of Vancomycin and Meropenem in Pediatric Extracorporeal Membrane Oxygenation Support

Objective: Describe primary pharmacokinetic/pharmacodynamic (PK/PD) parameters of vancomycin and meropenem in pediatric patients undergoing ECMO and analyze utilized dosing to reach PK/PD target.

Design: Prospective, multicentric, population PK analysis.

Setting: Two hospitals with pediatric intensive care unit.

Patients: Pediatric patients (1 month - 15 years old) receiving vancomycin and meropenem for empiric or definitive infection treatment while ECMO support.

Measurements and Main Results: Four serum concentration were obtained for patients receiving vancomycin (n = 9) and three for meropenem (n = 9). The PK/PD target for vancomycin was a ratio of the area under the curve to the minimal inhibitory concentration (AUC/MIC) of >400, and for meropenem was 4 times above MIC for 50% of the dosing interval (fT_50% > 4xMIC). Pharmacokinetic modeling was performed using PMetrics 1.5.0. We included nine patients, with 11 PK profiles for each antimicrobial. The median age of patients was 4 years old (2 months - 13 years) and 45% were male. Creatinine clearance (CL) was 183 (30–550) ml/min/1.73 m². The median dose was 13.6 (range 10–15) mg/kg every 6–12 h and 40 mg/kg every 8–12 h for vancomycin and meropenem, respectively. Two compartment models were fitted. Weight was included as a covariate on volume of the central compartment (Vc) for meropenem. Weight was included as a covariate on both Vc and clearance (CL) and serum creatinine was also included as a covariate on CL for vancomycin. The pharmacokinetic parameters CL and Vc were 0.139 ± 0.102 L/h/kg and 0.289 ± 0.295 L/kg for meropenem and 0.060 ± 0.055 L/h/kg and 0.419 ± 0.280 L/kg for vancomycin, respectively. Across each dosing interval 91% of patients achieved the PK/PD targets for adequate exposure for meropenem and 63.6% for vancomycin.

Conclusion: Pharmacokinetic/pharmacodynamic objectives for vancomycin were achieved partially with conventional doses and higher dosing with extended infusion were needed in the case of meropenem.

Optimized Dosing Regimens of Meropenem in Septic Children Receiving Extracorporeal Life Support

Objectives: To develop a population pharmacokinetic model of meropenem in children with sepsis receiving extracorporeal life support (ECLS) and optimize the dosage regimen based on investigating the probability of target attainment (PTA). Methods: The children with sepsis were prospectively enrolled in a pediatric intensive care unit from January 2018 to December 2019. The concentration-time data were fitted using nonlinear mixed effect model approach by NONMEM program. The stochastic simulation considering various scenarios based on proposed population pharmacokinetics model were conducted, and the PTAs were calculated to optimize the dosage regimens. Results: A total of 25 children with sepsis were enrolled, of whom13 received ECMO, 9 received CRRT, and 4 received ECMO combined with CRRT. 12 children received a two-step 3-h infusion and 13 children received 1-h infusion. Bodyweight and creatinine clearance had significant impacts on the PK parameters. ECMO intervention was not related to the PK properties. If 100%T > MIC was chosen as target, children receiving 40 mg/kg q8h over a 3 h-infusion only reached the PTA up to 77.4%. If bacteria with MIC 2 mg/L were to be treated with meropenem and the PTA target was 50%T > MIC, a dose of 40 mg/kg q8h for 1 h infusion would be necessary. Conclusions: The PK properties of meropenem in septic children receiving extracorporeal life support were best described. We recommended the opitimized dosing regimens for septic children receiving ECLS depending on the PTA of PK target 50%T > MIC and 100%T > MIC, for children with sepsis during ECLS with different body weight, estimated creatinine clearance (eCRCL) and MIC of bacteria.